To Physiology (Neurophysiology) MIDDLESEX UNIVERSITY1 M00646922 MIDDLESEX

To compare the Somatosensory Evoked Potentials (SSEPs) and Motor Evoked Potentials (MEPs) of diabetic and non-diabetic patients during intraoperative monitoring of Scoliosis surgery DISSERTATION Module: Research Project BMS4997 Supervisor: Dr. Marc Rayan Date of submission: 10-09-2018 Student: MUHAMMAD ANEES SARWAR Student ID: M00646922 M.Sc. Clinical Physiology (Neurophysiology) MIDDLESEX UNIVERSITY1 M00646922 MIDDLESEX UNIVERSITY TABLE OF ABBREVIATIONS Abbreviation Terms 1.

DM Diabetes Mellitus 2. GDM Gestational Diabetes Mellitus 3. WHO World Health Organization 4.

IDF International Diabetes Federation 5. MODY Maturity-Onset Diabetes of the Young 6. CT Computed Tomography 7. MRI Medical Resonance Imaging 8. TIVA Total Intravenous Anaesthesia 9.

MIS Minimally Invasive Surgery 10. EP’s Evoked Potentials 11. MEPs Motor Evoked Potentials 12. SSEPs Somatosensory Evoked Potentials 13. IONM Intraoperative Neuromonitoring 14. SCEPs Spinal Cord Evoked Potentials 15. D-Waves Direct Waves 16.

EMG Electromyography 17. EEG Electroencephalography 18. SNAP Sensory Nerve Action Potentials 19. TcMEPs Transcranial Motor Evoked Potentials 20.

CMAP Compound Muscle Action Potential 21. APB Abductor Pollicis Brevis 22. ADM Abductor Digiti Minimi 23. TA Tibialis Anterior 24.

AH Abductor Hallucis 25. GCN Gastrocnemius 26. QUADS Quadriceps 27. amp Amplitude 28. OL Onset Latency 29.

PE Pulmonary Embolism 30. DVT Deep Vein Thrombosis 31. CMCT Central Motor Conduction Time 32.

PCT Peripheral Conduction Time 33. JOA Japanese Association Score 34. CCT Central Conduction Time 35. Ho Null Hypothesis 36.

H? Alternative Hypothesis 37. MAC Mean Alveolar Concentration2 M00646922 MIDDLESEX UNIVERSITY 38. N-DM Non-Diabetic Group 39.

PTN Posterior Tibial Nerve 40. MN Median Nerve 41. Fpz Prefrontal Region 42. Cz Central Region 43. ms Milliseconds 44.

µV Microvolts 45. RMN Right Median Nerve 46. LMN Left Median Nerve 47. RTN Right Posterior Tibial Nerve 48.

LTN Left Posterior Tibial Nerve 49. R-APB Right Abductor Pollicis Brevis 50. L-APB Left Abductor Pollicis Brevis 51. R-TA Right Tibialis Anterior 52.

L-TA Left Tibialis Anterior 53. R-AH Right Abductor Hallucis 54. L-AH Left Abductor Hallucis 55. R-QUAD Right Quadriceps 56.

L-QUAD Left Quadriceps 57. BAEPs Brainstem Auditory Evoked Potentials 58. VEPs Visual Evoked Potentials3 M00646922 MIDDLESEX UNIVERSITY LIST OF FIGURES Figure Page Figure-1 Diagnosis of Diabetes Mellitus. 12 Figure-2 Complications of diabetes.

13 Figure-3 Types of scoliosis according to the spine. 14 Figure-4 Measurement of Cobb angle with an inclinometer. 17 Figure-5 Dissimilar stages of scoliosis correction surgery. 19 Figure-6 Kyphoscoliosis before and after correction surgery. 20 Figure-7 MEPs during IONM of Scoliosis correction surgery. 22 Figure-8 SSEPs and Free-run EEG within good waveform during Scoliosis surgery. 23 Figure-9 Spinal SSEPs during Scoliosis surgery.

25 Figure-10 Lower limb muscles used for MEPs recording. 26 Figure-11 Upper limb muscles used for MEPs recording. 27 Figure-12 Free run EMG, EEG and TcMEPs during scoliosis correction surgery.

29 Figure-13 Effect of anaesthesia on MEPs during IONM. 32 Figure-14 Corkscrew, surface electrodes and placement of corkscrew electrodes according to the 10-20 international system. 44 Figure-15 Stimulation and recording sites of somatosensory evoked potentials. 45 Figure-16 Measurement method for amplitude and onset latency (OL). 47 Figure-17 Flowchart for analysis of the difference between interdependent data.

48 Figure-18 Flow Chart for an analysis of the difference between independent data. 49 Figure-19 Pie chart for percentage of gender distribution in sample size. 51 Figure-20 Bar chart for gender distribution among groups.

52 Figure-21 Bar chart representing age groups. 53 Figure-22 Bar chart illustrating age distribution according to diagnosis. 54 Figure-23 Bar chart for percentage change is SSEPs amplitude among both groups.

77 Figure-24 Bar chart for the percentage change in SSEPs onset latency among groups. 78 Figure-25 Bar chart for the percentage change in MEPs amplitude among groups. 79 Figure-26 Bar chart for the percentage change in MEPs onset latency among groups. 804 M00646922 MIDDLESEX UNIVERSITY LIST OF TABLES Table Page Table-1 Sample selection criteria. 41 Table-2 Non-Diabetic group median nerve SSEPs amplitude difference. 56 Table-3 Non-Diabetic group median nerve SSEPs onset latency difference.

57 Table-4 Non-Diabetic group posterior tibial nerve SSEPs amplitude difference. 59 Table-5 Non-Diabetic group posterior tibial nerve SSEPs onset latency difference. 60 Table-6 Diabetic group median nerve SSEPs amplitude difference. 52 Table-7 Diabetic group median nerve SSEPs onset latency difference. 63 Table-8 Diabetic group posterior tibial nerve SSEPs amplitude difference.

65 Table-9 Diabetic group posterior tibial nerve SSEPs onset latency difference. 66 Table-10 Non-Diabetic MEPs amplitude difference. 68 Table-11 Non-Diabetic MEPs onset latency difference. 70 Table-12 Diabetic group MEPs amplitude difference. 72 Table-13 Diabetic group MEPs onset latency difference.

74 Table-14 Comparison of SSEPs and MEPs among the Non-Diabetic and Diabetic group. 76 Table-15 Median Nerve SSEPs raw data. 99 Table-16 Posterior Tibial Nerve SSEPs raw data.

100 Table-17 MEPs amplitude (µ?) raw data. 101 Table-18 MEPs onset latency (OL) raw data. 1025 M00646922 MIDDLESEX UNIVERSITY TABLE OF CONTENTS TABLE OF ABBREVIATIONS ..

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……………………………………………………………………. 3 LIST OF TABLES …………………………………………………………………………………………………….. 4 ACKNOWLEDGEMENT ………………………………………………………………………………………….. 7 ABSTRACT ……………………………………………………………………………………………………………… 8 SECTION-I ………………………………………………………………………………………………………………. 9 INTRODUCTION:……………………………………………………………………………………………….. 10 1. Diabetes Mellitus (DM): …………………………………………………………………………………. 10 2. Scoliosis: ………………………………………………………………………………………………………. 14 3. Scoliosis Correction Surgery: ………………………………………………………………………….. 17 4. Intraoperative Neurophysiological monitoring (IONM): …………………………………….. 22 5. The rationale of the study: ………………………………………………………………………………. 33 6. Literature Review: …………………………………………………………………………………………. 33 7. The aim of the study: ……………………………………………………………………………………… 37 8. Hypothesis: …………………………………………………………………………………………………… 37 SECTION-II ……………………………………………………………………………………………………………. 38 MATERIALS AND METHODS: …………………………………………………………………………… 39 1. Study Design: ……………………………………………………………………………………………….. 39 2. Sampling Technique: ……………………………………………………………………………………… 39 3. Study Setting: ……………………………………………………………………………………………….. 39 4. Study Duration:……………………………………………………………………………………………… 40 5. Sample Size Estimation: …………………………………………………………………………………. 40 6. Sample Selection Criteria: ………………………………………………………………………………. 40 7. Ethical Consideration: ……………………………………………………………………………………. 42 8. Methodology and material used: ……………………………………………………………………… 42 9. Data Collection and Data Analysis:………………………………………………………………….. 46 SECTION-III ………………………………………………………………………………………………………….. 50 RESULTS: ………………………………………………………………………………………………………….. 51 1. Percentage of gender distribution in sample size: ………………………………………………. 51 2. The frequency of gender distribution in the groups: …………………………………………… 526 M00646922 MIDDLESEX UNIVERSITY 3. Patients distribution in different age groups: ……………………………………………………… 53 4. Patients distribution in age groups according to diagnosis: …………………………………. 54 5. Question 1: Difference between baseline and closing SSEPs of Median nerve among the non-diabetic group? ……………………………………………………………………………………… 55 6. Question 2: Difference between baseline and closing SSEPs of Posterior Tibial nerve among the non-diabetic group? …………………………………………………………………………… 58 7. Question 3: Difference between baseline and closing SSEPs of Median nerve among the diabetic group? …………………………………………………………………………………………….. 61 8. Question 4: Difference between baseline and closing SSEPs of Posterior Tibial nerve among the diabetic group? ………………………………………………………………………………….. 64 9. Question 5: Difference between baseline and closing MEPs among the non-diabetic group? ……………………………………………………………………………………………………………… 67 10. Question 6: Difference between baseline and closing MEPs among the Diabetic group? ……………………………………………………………………………………………………………… 71 11. Question 7: Can Diabetes Mellitus lead to increase in onset latency and decrease in amplitude during intraoperative monitoring of scoliosis correction surgery? …………….. 75 12. Percentage change in SSEPS amplitude: …………………………………………………………. 77 13. Percentage change in SSEPs onset latency: …………………………………………………….. 78 14. Percentage Change in MEPs amplitude: …………………………………………………………. 79 15. Percentage change is MEPs onset latency: ………………………………………………………. 80 SECTION-IV ………………………………………………………………………………………………………. 81 DISCUSSION: …………………………………………………………………………………………………….. 82 Limitations: …………………………………………………………………………………………………………. 89 Recommendation: …………………………………………………………………………………………………. 89 CONCLUSION: …………………………………………………………………………………………………… 90 SECTION-V …………………………………………………………………………………………………………… 91 REFERENCES: ……………………………………………………………………………………………………. 92 SECTION-VI ………………………………………………………………………………………………………….. 96 APPENDIX-I: MIDDLESEX UNIVERSITY ETHICAL FORM: ………………………………. 97 APPENDIX-II: GHURKI TRUST TEACHING HOSPITAL ETHICAL REVIEW COMMITTEE (ERC) CERTIFICATE: …………………………………………………………………… 98 APPENDIX-III: SSEPs and MEPs raw data: ……………………………………………………………. 997 M00646922 MIDDLESEX UNIVERSITY ACKNOWLEDGEMENT I owe an massive debt of gratitude to my supervisors, Mrs Linda Howard, Clinical Neurophysiologist at Harley Street Clinic and Princess Grace Hospital London, and Mr Kamran Ayoob, Clinical Neurophysiologist, Ghurki Trust Teaching Hospital Lahore Pakistan, for their support from the formative stages of this dissertation to its final draft. Their sound advice and careful guidance were irreplaceable. I outspread my sincere appreciation to them for their pastoral heart, insight, patience, encouragement, positive criticism and support in bringing this work to completion. I also extend my gratitude and appreciation to my mentor Dr Marc Rayan, Course Leader, M.Sc. Clinical Physiology (Neurophysiology) Middlesex University London, for the deft ways in which he lovingly supported me throughout the whole of this work. His extreme generosity will be remembered always. I thankfully acknowledge the Ethical Review Committee (ERC) Ghurki Trust Teaching Hospital, chairman Professor Amir Aziz, for their kind assistance and supervision in data collection.8 M00646922 MIDDLESEX UNIVERSITY ABSTRACT Diabetes is a collection of metabolic syndromes categorised by the elevated level of the glucose in the body or hyperglycemia due to the shortcoming insulin secretions from the pancreas, defect in insulin action or both together. Scoliosis is a structural spinal deformity and three-dimensional deviation of the spinal axis with coronal curvature beyond 10º anteroposteriorly along with vertebral rotation and reduced kyphosis (irregular apparent shape of the spine) in thoracic curves. Scoliosis correction surgery is used to correct the spinal deformity. Intraoperative neurophysiological monitoring is a diagnostic method used during brain and spinal cord surgeries to halt all possible neurological damage, to detect significant neural structures, e.g. sensory and motor nerves during the operation and to decrease any substantial postoperative impairment with the help of somatosensory and motor evoked potentials. Twenty-six patients were analysed for selection criteria and allocated for diabetic and non-diabetic groups. Amplitude and onset latency of somatosensory and motor evoked potentials were measured from the limbs at the start of scoliosis surgery and statically compared with the closing amplitude and onset latency for both groups to find out differences. Wilcoxon Signed-rank and Paired T-test were used for this comparison. Variations of these results were statically compared between diabetic and non-diabetic groups with the help of Mann Whitney and Two-Sample T-test. P-value of the somatosensory and motor evoked potentials amplitude and onset latency was lower than the value of alpha (? = 0.05). The amplitude of the both somatosensory evoked potentials and motor evoked potentials were decreased (-1.78% to -14.92%) among diabetic patients as compared to the non-diabetic patients. Likewise, onset latency (OL) of somatosensory and motor evoked potentials was increased among both diabetic and non-diabetic groups. But, this increase in onset latency was significantly enlarged (0.08% to 9.79%) among people with diabetes than non-diabetic patients. It was concluded that diabetes mellitus does affect amplitude and onset latency, but these variations are not clinically noteworthy. These results will be helpful clinically to prevent false alarms during spinal cord surgical procedure among diabetic patients, to facilitate the surgical procedure precisely, and to plan the postoperative management according to the neuromuscular status of the nerve and muscles.9 M00646922 MIDDLESEX UNIVERSITY SECTION-I10 M00646922 MIDDLESEX UNIVERSITY INTRODUCTION: 1. Diabetes Mellitus (DM): Diabetes Mellitus is defined as a collection of metabolic syndromes categorised by the elevated level of the glucose in the body or hyperglycemia due to the shortcoming insulin secretions from the pancreas, defect in insulin action or both together. Chronic diabetes is mostly related to the continuing damage, malfunctioning and organ failure. Diabetes frequently affects the nerves, eyes, blood vessels, kidneys and heart in the body. Patient presents with the sign and symptoms of weight loss, polyuria, blurred vision, polydipsia and occasionally with the polyphagia. If diabetes remains untreated these problems convert into more severe types, for example, peripheral neuropathy, nephropathy, retinopathy and autonomic neuropathy. Diabetes Mellitus is mainly classified as Type-I Diabetes, Type-II diabetes and Gestational Diabetes Mellitus (GDM) (Association, 2014). Conferring to the World Health Organization (WHO), 108 million people were living with diabetes in 1980, which was increased four times in 2014. The International Diabetes Federation (IDF) estimated 151 million population with diabetes globally in 2000, which became 194 million in just three years. This number raised to 246, 285, 366, 382 and 415 million in 2006, 2009, 2011, 2013 and 2015 respectively. This data predicts how the prevalence of diabetes has been growing over current decades. A study assessed the prevalence of diagnosed diabetes in 2017 as 425 to 451 million depending upon age groups. They also founded that almost 49.7% people, over 224 million adults are living with undiagnosed diabetes (Cho et al., 2018, Khawaja et al., 2018). 1.1- Type-1 Diabetes Mellitus: Type-I Diabetes is defined as glucose intolerance due to the insulin deficiency resulting from the destruction of the beta cells of the pancreas. This type accounts for 5-10% of diabetes. The known aetiology behind this type is an autoimmune pathologic process which destroys the pancreatic beta cells and leads to the insulin deficiency. Type-1 diabetes is also known as Juvenile diabetes because it mostly affects the young adults and children. It’s also called insulin-dependent diabetes because patients’ needs subdermal insulin injections to maintain glucose concentration in the blood (Association, 2014). The incidence rate of type-I diabetes11 M00646922 MIDDLESEX UNIVERSITY is 40/1000000 in Finland, 1-8/1000000 in Pakistan and Egypt respectively and 0.1/1000000 in China (Amiri et al., 2016, Patterson et al., 2014). 1.2- Type-II Diabetes Mellitus: Type-II Diabetes is defined as glucose intolerance either due to the insulin resistance to its action or due to insufficient insulin secretion from the pancreas eventually lead to the hyperglycemia. This type of diabetes accounts for 90-95%. The possible aetiology behind this type is obesity, increased percentage of the body fat and poor lifestyle. Type-II diabetes is also known as non-insulin-dependent diabetes because drugs can increase the insulin secretion from the pancreas or they also can decrease the insulin resistance against glucose. It’s also called adult-onset diabetes because it mostly affects adults and old age population (Association, 2014). Prevalence of type-II diabetes in Pakistan is 11.7%. Males are more likely to get this type of diabetes with the prevalence of 11.20% than females 9.19% (Meo et al., 2016). 1.3- Gestational Diabetes (GDM): Gestational Diabetes Mellitus (GDM) is defined as glucose intolerance in the females during the pregnancy which habitually disappears afterwards the birth of the child. This type of diabetes can occur at any stage of the pregnancy but mostly recorded in the second half (Association, 2014). A study proposed that in 2017 almost 21.3 million live births were affected by hyperglycemia and 18.4 million cases were due to gestational diabetes mellitus (Cho et al., 2018). 1.4- Uncommon Variants of Diabetes: Diabetes mellitus has some other uncommon variants also. The glucose intolerance characterizes Maturity-Onset Diabetes of the Young (MODY) due to impaired insulin secretion without any problem with insulin action. The known cause for this variant is monogenetic defects of the beta-cells function in the pancreas. The other pathologies which can also lead to hyperglycemia and later diabetes include genetic defects in insulin action, e.g. Lipoatrophic diabetes, diseases of the exocrine pancreas, e.g. Pancreatitis, endocrinopathies, e.g. Acromegaly, Cushing syndrome, Hyperthyroidism. Drugs or chemical induced pathologies, e.g. glucocorticoids, Thiazides, Infections, e.g. Cytomegalovirus and other genetic syndromes, e.g. Down, Klinefelter and Turner syndrome etc. (Association, 2014).12 M00646922 MIDDLESEX UNIVERSITY 1.5- Diagnosis of Diabetes: Blood glucose concentration in the blood diagnoses of diabetes. Normal fasting levels of the blood glucose concentration are 80-100 mg/dl and normal levels after 2-3 hours taking meal are 120-140 mg/dl. In contrast, fasting blood glucose concentration for diabetic patients are 126+ and 2-3 hours after taking meal is 200 plus. Hb1ac is another laboratory test for diagnosis of diabetes which measures the blood glucose concentration. Normal levels are 5% or less than 5%, and for diabetics, this value is more than 6.5% (Gangwar et al., 2018). Patients experience serious complications of diabetes, and these complications become more severe as the disease progresses. A study in 2017 estimated that diabetes accounts for 9.9% of all types of the deaths and almost 5.0 million people die each year due to diabetes (Cho et al., 2018). Figure 1: Diagnosis of Diabetes Mellitus (Jiang, 2017). 1.7- Complications of Diabetes: Diabetic complications are divided into macrovascular and microvascular. Diabetic retinopathy is a microvascular complication which damages the small blood vessels to the eye leading to visual disability or blindness. Diabetic nephropathy is another chronic microvascular problem which affects the capillaries of the kidneys and disturbs the reabsorption, eventually causing renal failure or even death. Diabetic neuropathy is the utmost communal microvascular complication which arises either due to direct damage to the sensory nerves or either due to the damage to the blood vessels supplying the nerves. This complication cause burning sensations in hand and feet or complete sensory loss, diabetic ulcers, damage the limbs and13 M00646922 MIDDLESEX UNIVERSITY may lead to amputation, cause impotence in the males, body muscles weakness and poor wound healing. Macrovascular complications contain cardiovascular problems, e.g. atherosclerosis. Due to hyperglycemia glucose start depositing in the walls of the large arteries leading to the narrowing of the diameter eventually causing heart attack due to blockage of the coronary arteries (Papatheodorou et al., 2016). Figure 2: Complications of diabetes (Jiang, 2017).14 M00646922 MIDDLESEX UNIVERSITY 2. Scoliosis: Scoliosis is a structural spinal deformity and defined as three-dimensional (3D) deviation of the spinal axis with coronal curvature beyond 10º anteroposteriorly along with vertebral rotation and reduced kyphosis in thoracic curves. Spine turns and curves to the side in scoliosis. Naturally, spinal curves are present along the “sagittal plane” at the level of cervical, thoracic and lumbar spine. These curves work as a shock absorber to dispense the mechanical stress during the body movement and position the head over the pelvis. Scoliosis is a deformity in “coronal or frontal plane” rather than the sagittal plane. The coronal or frontal plane is a vertical line from the head to the foot and parallel to the shoulders. Coronal plane divides the body into front and back sections while the sagittal plane split the body into right and left (Trobisch et al., 2010). Scoliosis curves can be either S-shaped or C-shaped. Lumbar and cervical curves are known as lordosis, and thoracic curves are known as kyphosis. These curves can get worse as the child will grow. Cobb angle is used to calculate the size and angle of the curve. Scoliosis curves with the Cobb angle more than 90º can lead to the severe cardiopulmonary complications, with the risk of morbidity and mortality. Scoliosis is named after the area of the spine involved, e.g. Cervical scoliosis (C1-C6), Cervicothoracic scoliosis (C7-T1), Thoracic scoliosis (T2-T12), Thoracolumbar scoliosis (T12-L1), Lumbar scoliosis (L2-L4) and Lumbosacral scoliosis (L5-S1) (Rolton et al., 2014). Figure 3: Types of scoliosis according to the spine (Rolton et al., 2014).15 M00646922 MIDDLESEX UNIVERSITY 2.1- Non-Idiopathic Scoliosis and subtypes: Scoliosis can be diagnosed at any age from an infant to the older adult depending upon the pathogenesis. Generally, scoliosis is divided into non-idiopathic and idiopathic scoliosis. Non-idiopathic scoliosis is subdivided into congenital, neuromuscular and mesenchymal scoliosis. Congenital scoliosis is defined as spinal deformity due to embryological malformation of the one or more vertebrae which may occur at any level (Konieczny et al., 2012). This type of scoliosis can occur due to one of the following reasons, e.g. absence of vertebrae, malformed vertebrae, jointed vertebrae and partially formed vertebrae. Congenital scoliosis is not evident at the time of birth, but deformity starts as the child grow into adolescence (Popko et al., 2018). Neuromuscular scoliosis is defined as the presence of spinal deformity due to the insufficiency of the active stabilisers muscles to stabilise the spine secondary to neuromuscular or neurological disorders. The most common conditions which cause neuromuscular scoliosis includes cerebral palsy, Duchenne or Becker muscular dystrophies, spina bifida, spinal muscle dystrophies, poliomyelitis and spinal cord injuries. Mesenchymal scoliosis is defined as spinal deformity due to the insufficiency of the passive stabiliser muscles to stabilise the spine. The most common problems behind this type are Marfan’s syndrome, inflammatory diseases, mucopolysaccharidosis, open heart or thoracic surgeries and osteogenesis imperfecta (Konieczny et al., 2012, Popko et al., 2018). 2.2- Idiopathic Scoliosis and subtypes: Idiopathic scoliosis is defined as scoliosis without any known aetiology and accounts for more than 90% of all scoliosis in the world. Diagnosis of the idiopathic scoliosis is made after excluding all types of non-idiopathic scoliosis. Idiopathic scoliosis is also subdivided into infantile, juvenile, adolescent and adult scoliosis. Infantile scoliosis is defined as the presence of spinal deformity from the birth until the age of three (3) years without any cause. Prevalence of this type is 1% of all types of idiopathic scoliosis. Juvenile scoliosis is defined as development of spinal deformity at the age of 4-10 years without any known cause. Prevalence of this type is 10-15% of idiopathic scoliosis. Adolescent scoliosis is defined as development of spinal deformity at the age of 11-18 years without any known cause. The incidence of this type of scoliosis is almost 90% of all types of idiopathic scoliosis. Adult scoliosis is defined as development of the spinal deformity over the age of 18 years without any known cause.16 M00646922 MIDDLESEX UNIVERSITY Prevalence of this type varies from 8%-68% depending upon the age (Trobisch et al., 2010, Konieczny et al., 2012, Popko et al., 2018, Hresko, 2013). 2.3- Diagnosis of Scoliosis: The patient presentation and physical examination diagnose scoliosis. Patient presents with following signs, e.g. raised hips one or both, uneven shoulders with one shoulder edge more protruding than the other, the head is not aligned centrally, uneven waist and ribs may be prominent on one side. Physical examination includes “Adam’s forward bend test” in which patient bends forward with the feet together and knees straight with arms on the side. A positive test indicates the asymmetry in the ribs. Scoliometer is a device used to measure the angle of the deformity known as Cobb angle, from the coronal plane in scoliosis. Further investigations include spine, shoulder and hip x-rays, computed tomography scan (CT-scan), magnetic resonance imaging (MRI) and laboratory tests to confirm the aetiology of scoliosis. Treatment of scoliosis depends upon the severity of the curve. If Cobb angle is less than 25º, then physiotherapy is advised to strengthen the active and passive stabilisers muscles. If Cobb angle is 25º – 45º then Milwaukee brace is recommended for immature patients along with physiotherapy plan. And if Cobb angle greater than 45º then surgical treatment is the only option because patients may present with severe cardiopulmonary complications (Konieczny et al., 2012, Hresko, 2013). The Figure 4 below is illustrating the measurement method for Cobb angle with an inclinometer. The patient is in bending position with knees straight and arms sideways reaching toward feet. Left side is displaying a posteroanterior x-ray of a patient with kyphoscoliosis. Thoracic spine has 26º of Cobb angle, and lumbar spine has 15º (Hresko, 2013).17 M00646922 MIDDLESEX UNIVERSITY Figure 4: Measurement of Cobb angle with an inclinometer (Hresko, 2013). 3. Scoliosis Correction Surgery: Scoliosis correction surgery is used to correct the spinal deformity. Surgery is indicated if the Cobb angle of the growing child is more than 40º – 45º with the immature skeleton and more than 50º in the case of adults. In the case of idiopathic scoliosis, correction surgery is valuable to decrease the mechanical problems, e.g. chronic back pain due to spinal deformity. This surgery is also advisable cosmetically because the patient will be more active, independent and confident in the society. In the case of neuromuscular scoliosis, surgery is indicated to prevent further progression of the curve, to improve wheelchair posture of the patient, to decrease cardiopulmonary sign and symptoms and to help in nursing care. The main objectives of the scoliosis surgery are to prevent long-term disability, to halt the progression of the Cobb angle, to achieve good correction in frontal as well as sagittal plane and to achieve solid fusion of the vertebrae’s (Gibson, 2004, Rolton et al., 2014).18 M00646922 MIDDLESEX UNIVERSITY 3.1- Posterior approach: Scoliosis surgery team includes spine surgeon and his/her assistant, anaesthetic, neurophysiologist, x-ray technician, operation-theatre assistant and operation-theatre nurse. A spine surgeon is the leader of the team who decides the whole procedure. An anaesthetic doctor prepares the patient for the surgery in the anaesthetic room by injecting intravenous anaesthetic agents and maintain the vitals of the patients along with the anaesthesia throughout the surgical procedure. Neurophysiologist monitors the somatosensory evoked potentials and motor evoked potentials to prevent any possible neurological complication. Operation theatre assistant assists the surgeon throughout the surgery in instrumentation. X-ray technician takes the images on the demand of the surgeon during surgery. Operation theatre nurse maintains the environment of the theatre and helps every single person in the theatre. The most common approach used in the scoliosis is the posterior approach. When a patient is brought inside the theatre patient is almost under a deep sleep. Patients are shifted onto the surgical table in a prone position. Operation theatre assistant shaves and cleans the back of the patient with povidone. Surgeon mark the Cobb angle and incision line. The incision is given along the curve of the deformity using electrocautery. Skin and fascia are incised to reach the vertebrae. Spinal ligaments are carved to approach the paraspinal muscles. The paraspinal muscles are reflected, and an approach is taken to cut the interspinal ligaments. Spinal process along with the facet joints are broken down. Harrington rod instrumentation is used in this surgery. Pedicle screws or laminar hooks are inserted according to Cotrel-Dubousset design. Space is built between the vertebral body and the pedicle, and the pedicle screw is embedded in the space of all targeted vertebrae’s. The diagram below is representing the various stages during scoliosis correction surgery including screw fixation and rod insertion. Anesthesiologist maintains Total intravenous anaesthesia (TIVA) and gases, e.g. isoflurane, sevoflurane etc. which keeps the patient in a deep sleep as well as preserve the blood pressure. At the end of the surgery when pedicle screws are inserted in the all vertebrae’s, contoured rod are places to correct the deformity in all planes. Distraction and compression are applied to provide stability. The spine is fused by adding bone graft to the curved area of the spine. The surgeon closes the skin by suturing the fascia and the skin. The adhesive dressing is applied on the wound to keep the wound safe from contamination. This system allows almost 60-80% correction of the spinal deformity as well as immediate ambulation without the need of bracing. The rate of19 M00646922 MIDDLESEX UNIVERSITY neurological complications of this surgery is 0.2-1.8% (Gibson, 2004, Rolton et al., 2014, Trobisch et al., 2010, Popko et al., 2018, Surgeons, 2018). Figure 5: Dissimilar stages of scoliosis correction surgery. Diagram illustrating deformed Spine, pedicle screws placement, rod placement and corrected spinal deformity (2018). 3.2- Anterior approach: The anterior approach is another technique in which patient lies on the side. The surgeon makes incision anterolaterally and deflates the lung to remove the rib. The spine is reached and fixed with screws to correct the deformity. This approach also has several advantages, e.g. quicker rehabilitation, better curve correction, improve spine mobilisation with fixation of fewer segments. The possible disadvantage of this approach is an elevated risk20 M00646922 MIDDLESEX UNIVERSITY of morbidity and continuous need of bracing for several months. Decompressive laminectomy is also used if the stenosis is present along with scoliosis(Surgeons, 2018). Minimally Invasive Surgery (MIS) is a new technique with a smaller incision than posterior and anterior approach. This technique is used in scoliosis with use of advanced fluoroscopy and endoscopy. In juvenile and infantile scoliosis instead of Harrington rods, manually or magnetically expandable or growing rods are used (Surgeons, 2018, Rolton et al., 2014). The figure below is representing x-rays of a 14-year old girl with scoliosis. Left two x-rays are demonstrating S-shaped kyphoscoliosis with 90º Cobb angle. X-rays on the right side are depicting almost complete correction of the deformity with multiple level transpedicular screw fixation surgery (Trobisch et al., 2010). Figure 6: Kyphoscoliosis before and after correction surgery (Trobisch et al., 2010).21 M00646922 MIDDLESEX UNIVERSITY 3.3- Risks and complications: Risk of spinal cord injury during scoliosis surgery is decreasing with the advancement of the techniques. Scoliosis research society stated that the risk is between 0.3-0.6% and according to another study risk of spinal cord injury is between 0.2-1.8%. The most common cause of the neurological deficit is a contusion of the spinal cord either through tools or either through implant itself. During surgery, radicular arteries can also get stretched or compressed leading to the ischemic injury of the spinal cord. Sometimes, epidural hematoma and distraction injury of the spinal cord can also cause the neurological deficit. Prolong position of the patient on the surgical table can compress the individual nerve or blood vessel or whole brachial plexus causing neuronal injury. Motor pathways are most commonly affected by these types of ischemic injuries which affects anterior spinal arteries (Turner et al., 2016, Leong et al., 2016). The diagram below is signifying the clinical worth of intraoperative monitoring during scoliosis surgery by comparing motor evoked potentials recorded from lower limb muscles at various times (black line) with the baseline (green line). The symbol P is representing positive peak and N is depicting a negative peak. A) Motor evoked potentials after insertion of the rod into the screw for derotation. A drop of the amplitude of more than 50% can be seen bilaterally (black line) as compared to baseline (green line). B) Motor evoked potentials get recovered after correction release by removal of screws and rod. C) The amplitude of the MEPs again declined after reinsertion of the implant. D) Motor evoked potentials amplitude recovered again by injecting dexamethasone and increasing mean arterial pressure (MAP) (Park and Hyun, 2015).22 M00646922 MIDDLESEX UNIVERSITY Figure 7: MEPs during IONM of Scoliosis correction surgery (Park and Hyun, 2015). 4. Intraoperative Neurophysiological monitoring (IONM): Intraoperative neurophysiological monitoring (IONM) is a method used during brain and spinal cord surgeries to halt all possible neurological damage, to detect significant neural structures, e.g. sensory and motor nerves during the operation and to abate any substantial postoperative impairment (Kim et al., 2013). This modality is in use from the last three decades to evaluate the neurological function during brain and spinal cord surgeries specifically for scoliosis. Evidence proves that intraoperative monitoring modalities make us accessible to critical information during operations which allow us to provide neurologically efficient results to the patient at the end of the surgery. Intraoperative monitoring work on a principle to stimulate either nerves or brain itself and record the response away from the site of stimulation in the form of signals called “evoked potentials (EP’s). During scoliosis surgery IONM help neurophysiologist to identify neurological insult and aware the surgeon to take decision accordingly. Intraoperative neurophysiological monitoring is basically an amalgamation of23 M00646922 MIDDLESEX UNIVERSITY different components including somatosensory evoked potentials (SSEPs), motor evoked potentials (MEPs), spinal cord evoked potentials (SCEPs), direct waves (D-waves), electromyography (EMG) and electroencephalography (EEG) (Chang et al., 2016, Mo et al., 2017). The figure below is representing the standard waveform with quiet similar baseline amplitude and latencies at various times interval of lower limb somatosensory evoked potentials (SSEPs) and free running electroencephalography (EEG) throughout the scoliosis correction surgery. Redline is illustrating the baseline, and the green line is depicting the last saved average. The white mark is showing that stimulation is under process. Free run EEG waves are representing that patient under good sleep. Figure 8: SSEPs and Free-run EEG within good waveform during Scoliosis surgery (2018).24 M00646922 MIDDLESEX UNIVERSITY 4.1- Somatosensory Evoked Potentials (SSEPs): Somatosensory Evoked Potentials (SSEPs) are defined as the repetitive stimulation of the peripheral nerves (median/ulnar nerves for upper limb and posterior tibial/peroneal nerves for lower limb) either mechanically or electrically and then average electrical response of the primary sensory pathways is recorded from Fpz, Cz, C3′ and C4′ by signal averaging in the form of action potential. This action potential is generated at the surface of the nerve so known as sensory nerve action potential (SNAP). Somatosensory evoked potentials are used during intraoperative neurophysiological monitoring to assess the efficiency of the sensory pathways from the peripheral nerves. SSEPs were first used in the 1970’s but were not much popular. In 1977 Nash et al. defined the importance of the SSEPs, and they are now most common during scoliosis surgery (Buckwalter et al., 2013). SSEPs monitors the path of the dorsal column from the nerve to the cerebral cortex via the spinal cord. So, they can be recorded from both areas using a corkscrew or epidural electrode respectively. Dorsal column-medial lemniscus pathway is carried by myelinated, large diameter, fast conducting muscle and cutaneous afferent fibres. This pathway carries a vibration, tactile discrimination, proprioception from muscles and joints and crude or light touch. For SSEPs electrical stimulation subdermal stimulating surface electrodes are placed on the median, ulnar or radial nerve for upper limb and posterior tibial or peroneal nerve for lower limb. Electrical impulse excites the peripheral nerve and generates a sensory nerve action potential which propagates towards the contralateral sensory part of the cerebral cortex. Subdermal corkscrew active electrodes are placed on the Cz’/ C1’/ C2’/ C3′, and C4′ and reference electrodes at Fz or Fpz as a recording array. Nerves are usually stimulated at a frequency of 3 Hz with 0.2ms duration and an average 25mA intensity. Sensory nerve action potentials amplitude and latency are used as a measurement criterion. SSEPs are considered abnormal if latency is increased more than 10% or 2ms with a decrease in 50-70% amplitude. Possible mechanisms which can alter the SSEPs amplitude and latency include ischemia, anaesthesia (volatile agents, e.g. nitrous oxide, isoflurane), hypothermia, hypotension, mechanical compression, decreased hematocrit and patients age, height, and length of limbs. The advantage of monitoring SSEPs is it can detect injury suddenly even in neurologically compromised patients, and it can also record continuously. SSEPs are also very helpful to diagnose the positional or postural injury. Studies proved that the average sensitivity of the somatosensory evoked potentials is 92% with a range25 M00646922 MIDDLESEX UNIVERSITY between 27-100%. Specificity of the SSEPs varies between 92-98%. Limitations of somatosensory evoked potentials include the requirement of the signal averaging and it does not monitor corticospinal pathways (Hwang et al., 2012, Park and Hyun, 2015, Azabou et al., 2014, Gavaret et al., 2013). The Figure 9 below depicting the standard somatosensory evoked potentials (SSEPs) with the upright waveform from montage C3′-Fpz, Cz’-Fpz, C4′-Fpz and C5′-FPz.The numbers P23, P13 and P35, are representing the normal positive peak latency of 23, 13 and 35 ms respectively among the average population. Likewise, N20, N11, N30 and N45 are illustrating normal negative peak latency of 20, 11, 30 and 45 ms respectively among the healthy population. The black line is a closing waveform, and the green line is baseline potentials. Figure 9: Spinal SSEPs during Scoliosis surgery (Park and Hyun, 2015). 4.2- Motor Evoked Potentials (MEPs): Transcranial Motor Evoked Potentials (TcMEPs) or motor evoked potentials (MEPs) are defined as monitoring the activity of the corticospinal tracts through stimulation of the cerebral cortex at the scalp and recording the compound muscle action potential (CMAP) directly from the muscles. This technique was first introduced in 1986. Corkscrew electrodes are placed on the scalp C3, C4, C1, C2, Cz and 6 cm in front of the Cz according to the 10-20 international system for stimulation over the motor cortex area. Compound muscle action potentials (CMAP) are recorded from the peripheral muscles (Hwang et al., 2012). For upper26 M00646922 MIDDLESEX UNIVERSITY limb needle electrodes are placed inside one muscle from thenar eminence specifically abductor pollicis brevis muscle (APB), abductor digiti mini (ADM) from hypothenar muscles, 1st dorsal interosseous, brachioradialis, biceps and deltoid depending upon the vertebrae involved during scoliosis surgery. For lower limb needle electrodes are inserted into tibialis anterior (TA), abductor halluces (AH), gastrocnemius (GCN) and quadriceps. If surgery involves sacral nerve roots, then electrodes are also placed inside the anal sphincter and diaphragm muscles. Diagrams below is illustrating the anatomy of some of these muscles. Figure 10: Lower limb muscles used for MEPs recording (AMERMAN, 2018)27 M00646922 MIDDLESEX UNIVERSITY Figure 11: Upper limb muscles used for MEPs recording (AMERMAN, 2018). Stimulation intensity of the MEPs varies from 250V to 750V with duration of each pulse 0.5 ms. The frequency of MEPs kept as 0.5 to 2 Hz because motor evoked (MEPs) potentials do not need signal averaging. This technique of stimulation is known as train stimulus technique. Generally, MEPs are considered abnormal based on “all or none criteria”. Some studies suggest that MEPs should consider abnormal if the amplitude of the CMAP drops 50-80 % (Park and Hyun, 2015). According to a survey, MEPs are deemed unusual based on28 M00646922 MIDDLESEX UNIVERSITY three criteria’s including threshold, amplitude and waveform during intraoperative monitoring. Threshold level criterion states that neurological deficit can be found if more than 100V stimulus voltage required during MEPs monitoring for more than an hour to get a response. If this criterion is used, there will be no false positive or negative results. According to amplitude criterion, if the amplitude of the CMAP decreases insistently during surgery when the surgeon is placing some screw or correcting the deformity using compression or if 80% amplitude drops as compared to the baseline, these are a truly positive sign. Waveform criteria are defined as reformed morphology and duration of CMAP which is associated with an increase in voltage (Langeloo et al., 2007). The advantage of using motor evoked potentials (MEPs) during intraoperative monitoring does not require any averaging and immediate feedback is also available. The disadvantage of monitoring MEPs includes patients’ needs bite block otherwise lip or tongue laceration can occur. MEPs monitoring required at least partially intact motor pathways. Another limitation is MEPs are not the modality of choice in patients with cardiac arrhythmias, scalp burns, epilepsy and mandibular fracture (Azabou et al., 2014, Park and Hyun, 2015, Gavaret et al., 2013). The Figure 12 below is illustrating the Transcranial motor evoked potentials (TcMEPs), free run electromyography (EMG) and free run electroencephalography (EEG) during intraoperative monitoring of the scoliosis surgery. Free run EMG is running smoothly without any spike or burst. Some interference can be seen in the right gastrocnemius (GCN) and abductor hallucis (AH) possibly due to the surgical artefact. Transcranial MEPs can be seen with good waveform and amplitude recorded from bilateral Abductor pollicis brevis (APB), Quadriceps (QUADS), Tibialis Anterior (TA), Gastrocnemius (GCN) and Abductor Hallucis (AH). The right side of the diagram is displaying stacks of MEPs recorded throughout the scoliosis correction surgery with proper amplitude. Free running EEG is depicting the excellent state of sleep and anaesthesia (2018).29 M00646922 MIDDLESEX UNIVERSITY Figure 12: Free run EMG, EEG and TcMEPs during scoliosis correction surgery (2018). 4.3- Spinal Motor Evoked Potentials (D-Waves): Spinal Motor Evoked Potentials (SCMEPs) or Direct waves (D-waves) are defined as compound action potentials generated by direct stimulation of the axons with conduction velocity 50 m/s. Corkscrew electrodes are placed over the motor cortex for stimulation, and compound corticospinal action potentials are recorded in the form of D-waves from the spinal cord by inserting subdural or epidural electrodes. Stimulation is given with duration of 0.5-1 ms, intensity of 80-100 mA and frequency of 0.5-2 Hz. D-waves provided real-time feedback and considered abnormal if amplitude drops more than 50% as compared to baseline potentials. If D-waves show abnormal potentials during surgery, the probability of severe neurological deficit is high after surgery, e.g. paraplegia. The advantage of D-waves is they have real30 M00646922 MIDDLESEX UNIVERSITY prognostic value. They are very sensitive to changes during intramedullary spinal cord resection tumours. Limitations of the D-waves are that they cannot be monitored in the children and spinal levels below T12 due to less corticospinal tract fibres (Park and Hyun, 2015, Gavaret et al., 2013). 4.4- Neurogenic Motor Evoked Potentials: Neurogenic motor evoked potentials are also used during spinal cord surgeries. This technique involves stimulation of the spinal cord using epidural electrodes and recording the potentials from the peripheral nerves via surface electrodes. Electrode used for stimulation is a flexible spinal electrode which is inserted by the surgeon proximally near the operating field into the epidural space. Intensity is kept between 20-50 mA with a frequency of 4.1 Hz and duration of 1ms for stimulation. Median, posterior tibial or sciatic nerve is used as recording site (Park and Hyun, 2015, Gavaret et al., 2013). 4.5- Pedicle Screw Testing: Pedicle screw testing is a technique which is valuable during scoliosis surgery to evaluate the integrity of the pedicle screw with the help of triggered EMG. Normally, cortical bone is an electrical insulator for a well-placed pedicle screw from the nerve root due to the distance between them. But if a pedicle screw is not properly placed and breach the medial pedicle boundary, it will irritate the nerve root which will be displayed as a CMAP. When an incorrect screw is stimulated with the intensity of 5-30 mA, frequency of 0.8 Hz and duration of 0.2 ms, then the myotomes of the irritated root will depict a sudden CMAP (Gavaret et al., 2013). The advantage of this technique is it’s straightforward and highly sensitive for transpedicular screw fixation surgeries. This technique is also useful during minimally invasive surgeries to place the insert safely. Limitations include its less sensitive for thoracic spine vertebrae and only provide information regarding pedicle screw integrity without any evidence about neurological injury (Park and Hyun, 2015). 4.6- Free-running Electromyography (EMG): Electromyography (EMG) used during intraoperative monitoring is known as free-running electromyography or spontaneous electromyography. This type of EMG is used to monitor specifically selected nerve root function during the spinal cord operation. EMG depicts31 M00646922 MIDDLESEX UNIVERSITY real-time data from the peripheral muscles and widely used during spinal instrumentation surgeries, e.g. scoliosis and trans pedicle screw fixation to avoid any postoperative radiculopathy. There is no need for stimulation because its automatically runs throughout the surgery and predict irritation to the nerve root as a waveform. Recording sites are peripheral muscles based on their myotomes, e.g. for lower limb iliopsoas (L1), adductor longus (L2), vastus lateralis (L3), vastus medialis (L4), tibialis anterior and extensor halluces longus (L5), gastrocnemius and peroneus longus (S1) and perianal and urethral sphincter (S2-S5). For upper limb supraspinatus (C4), biceps and deltoid (C5), wrist extensors (C6), wrist flexors and finger extensors along with triceps (C7), finger flexors and hand intrinsic muscles (C8), hand intrinsic muscles only (T1) and rectus abdominis (T6-T12). Spontaneous EMG is continued without any baseline, any compression, surgical instrument irritation, pulling or stretching of the nerves will display neurotonic discharges which encompass burst and spike waves (Park and Hyun, 2015, Gavaret et al., 2013). 4.7- Free-running Electroencephalography (EEG): Electroencephalography (EEG) is also used during intraoperative neuromonitoring of scoliosis surgery to assess the patient’s cortical functional level. This technique involves only two channel continuous EEG to monitors the effect of the anaesthesia and sleep status during the surgery. During deep sleep and deep anaesthesia patient’s EEG depicts a burst suppression pattern. Correspondingly, if the level of anaesthesia gets lighter, EEG displays fast alpha activity. Clinical neurophysiologist can share this information with the anaesthetic doctor to maintain the anaesthetic levels (Mo et al., 2017). 4.8- Pharmacological and Physiological factors and artefacts during IONM: Sensory and motor evoked potentials are highly sensitive to both pharmacological and physiological factors. Inhaled anaesthetics, e.g. nitrous oxide or halogenated agent’s isoflurane, sevoflurane can increase the latency and reduce the amplitude causing false positive alarming criteria. While intravenous anaesthetics, e.g. propofol also have the similar effect but to a lesser extent. Mostly intravenous agents, e.g. propofol along with ketamine or remifentanil are used during intraoperative monitoring of scoliosis. Total intravenous anaesthesia (TIVA) containing propofol and halogenated gases with meagre percentage are also used sometimes. Physiological factors, e.g. hypothermia and hypotension can also decrease the amplitude and32 M00646922 MIDDLESEX UNIVERSITY increase the latency (Park and Hyun, 2015). Artefacts and pitfalls can also occur during IONM due to the surgical procedure, e.g. hammering or electrocautery. Movement of the respiratory muscles and electrocardiography artefacts can also be noticed sometimes (Kim et al., 2013). The figure below is illustrating the effect of anaesthesia on the motor evoked potentials. MEPs are very sensitive and can get abolished by halogenated agents. Figure A) is representing the drop-in amplitude due to halogenated agents in MEPs recorded from thenar muscles, Tibialis Anterior (TA) and Abductor Hallucis (AH). Figure B) is displaying a complete loss of MEPs due to halogenated agents but the patient had no postoperative neurological deficit (Kim et al., 2013). Figure 13: Effect of anaesthesia on MEPs during IONM (Kim et al., 2013).33 M00646922 MIDDLESEX UNIVERSITY 5. The rationale of the study: The somatosensory and motor evoked potential baseline waveforms among diabetic patients can be dissimilar to the non-diabetic patients. These changes can turn out to be worse during spinal cord surgeries and affect the procedure by alerting clinical neurophysiologist as well as the surgeon. The rationale of this study is that it can support us to comprehend the consequence of diabetes mellitus on the peripheral nerves and spinal cord in scoliosis surgery during intraoperative monitoring so postoperative management can be planned accordingly. 6. Literature Review: Diabetic neuropathy is one of the foremost complications of the diabetes mellitus. This is one of the significant microvascular problems which affects diabetic patients and causes issues in central, peripheral and autonomic nervous systems (Khawaja et al., 2018). Diabetic neuropathy causes ischemia of the nerve roots as well as motor pathways, e.g. corticospinal tracts and affects the functioning motor units of the peripheral limb muscles. While recording motor evoked potentials during intraoperative monitoring, a decrease in amplitude of compound muscle action potentials in diabetic patients illustrates this response (Allen et al., 2013). Diabetic neuropathy badly affects the myelin sheath of the nerve causing a decrease in nerve impulse transmission. This effect can also be monitored by somatosensory evoked potentials during intraoperative neuromonitoring which depicts decreased nerve conduction velocity and increased onset latency. (Arrthy et al., 2014). The incidence of scoliosis and diabetes together is not yet established. The possible reason for that is diabetes and scoliosis are not very common together, but there are so many cases registered too. Diabetes can affect the motor units firing or conduction of the nerve impulse during scoliosis correction surgeries. SSEPs and MEPs are 106.16 times more likely to detect these neurological insults (Thirumala et al., 2016). In chronic diabetic patients during scoliosis surgery, MEPs and SSEPs can mimic as a false positive change and can be taken as a false alarm. These false alarms are fluctuations in MEPs and SSEPs waveforms to a considerable level, but when the patient is awakened, there will be no neurological problem (Galloway et al., 2010). Nancy E. Epstein conducted a systemic review with a title “predominantly negative impact of diabetes on spinal surgery: A review and recommendation for better preoperative screening” in 2017. He reviewed different articles from PubMed related to the effect of34 M00646922 MIDDLESEX UNIVERSITY diabetes on the spinal surgeries, e.g. possible complications, mortality, morbidity and outcomes. He found a mortality rate of 40% among diabetic patients who underwent spinal cord surgeries due to severe complications, e.g. myocardial infarction, pulmonary embolism (PE) and deep vein thrombosis (DVT). He mentioned a slightly variable or negative impact of diabetes upon cervical spine surgeries, e.g. anterior cervical fusion and posterior cervical surgery. He said diabetic patients had significantly high genitourinary, respiratory and cardiac complications with high rates of postoperative infections as compare to non-diabetes. He proved statistically that diabetes has a significant impact during scoliosis correction surgeries and can lead to high rates of mortality and morbidity. He mentioned that diabetes has an adverse effect on the somatosensory and motor evoked potentials (SSEPs and MEPs) during intraoperative monitoring of spinal cord surgery. He correlates JOA score after 1-year of the operation and found that for diabetic patient’s central motor conduction times (CMCT), motor evoked potentials (MEPs) and peripheral conduction times (PCT) were abnormal. He also examined many other factors e.g. length of stay, epidural abscess, the rate of infection etc. and concluded that diabetic patients have a very high frequency of perioperative complications, morbidities, reoperation or readmission rates, longer length of stay, high rates of infections and postoperative complications than non-diabetic patients (Epstein, 2017). Shin JI and colleagues conducted a study to find out the effect of diabetes on scoliosis surgery with title “Impact of glycemic control on morbidity and mortality in adult idiopathic scoliosis patients undergoing spinal fusion” at the department of orthopaedic surgery, Icahn School of Medicine at Mount Sinai, New York in 2017. They analysed administrative data retrospectively. They extracted idiopathic scoliosis patients with age more than 45 years who underwent spinal fusion between the year 2002 to 2011. They divided patients into three groups controlled and uncontrolled diabetics along with non-diabetic groups. They compared the postoperative complications among these groups. They concluded that controlled diabetes is a risk factor for acute renal failure in adult patients undergoing spinal correction surgery. While patients with uncontrolled diabetes are more likely to get postoperative deep vein thrombosis, acute renal failure, haemorrhage, and neurological problems (Shin et al., 2017). Nakanishi K and colleagues conducted a study with the title “electrophysiological assessment of the motor pathway in diabetic patients with compressive cervical myelopathy” in the department of orthopaedic surgery, Hiroshima University, Japan in 2015. They divided35 M00646922 MIDDLESEX UNIVERSITY the patients into two groups. Group one was diabetic patients with compressive cervical myelopathy and group two patients were with only compressive cervical myelopathy. They stimulated cerebral motor cortex, and motor evoked potentials (MEPs) were recorded from abductor digiti minimi (ADM) and abductor hallucis muscles using transcranial magnetic stimulation. They also stimulated the ulnar and tibial nerve for somatosensory evoked potentials (SSEPs). They compared the results using Japanese Association Score (JOA) for cervical myelopathy. They concluded that group one JOA score was less than group two and MEPs, peripheral conductions time (PCT) and central conduction time (CCT) was more variable in group one as compare to group two due to diabetes (Nakanishi et al., 2015). Hyun Mi Oh with his colleagues Young Jin Ko and Bomi Sul conducted a very similar pilot study with the title “effects of diabetes mellitus on intraoperative monitoring of somatosensory evoked potentials” at Seoul St. Mary’s hospital in 2015. His objective was to find out the adverse effects of diabetes on SSEPs during intraoperative monitoring of brain surgeries. He obtained retrospective data from a Korean urban city major hospital. He included 14 patients in his study. He allocated seven diabetic patients into one group and other seven non-diabetic patients to another group. He excluded all possible complications which can alter the result of the study, e.g. patients with previous spinal cord surgery, neurosurgical operations, carpal tunnel syndrome and cerebrovascular diseases. He also excluded patients with peripheral neuropathies. He monitored SSEPs from the median nerves during unruptured cerebral aneurysm surgeries and craniotomies under total intravenous anaesthesia (TIVA). He found that cortical latency (N20) was pointedly deferred symmetrically in the diabetic group only. He also mentioned that interpeak latency (N20-P25) was increased in the diabetic group as compared to the non-diabetic group. So, he concluded that central conduction abnormalities could be present during intraoperative monitoring of the brain surgeries in diabetic patients without any central lesion (Oh et al., 2015). Arrthy S and his colleagues Vinodha R, Saravanan and Rajajeyakumar M conducted a study with the title “evaluation of peripheral and central neuropathy in Type-2 Diabetes Mellitus patients by using somatosensory evoked potentials” in the department of physiology, Thanjavur Medical College, Thanjavur in 2014. He divided the patients into two groups and allocated 40 patients in each group age within 40-60 years. Group one was a diabetic group which includes 18 females and 22 males with diagnosed diabetes while group two was control36 M00646922 MIDDLESEX UNIVERSITY group which comprises non-diabetic 18 women and 22 men. He excluded all patients with a history of alcoholism, neuropathies, systemic diseases, renal or liver disorders and cerebrovascular problems. He explained the testing procedure and protocol to the patients after getting consent from them. He stimulated the median nerve bilaterally in both groups and monitored SSEPs from sensory cortex of the brain. He concluded that SSEPs of cervical (N13) and cortical (N20) latencies were prolonged. He also found that central conduction time (N20-N13) was also increased. So, he summarised that type-2 diabetes mellitus affects the peripheral as well as central somatosensory pathways in diabetic patients (Arrthy et al., 2014). Pavol Kucera and colleagues conducted a very similar study with the title “spinal cord lesions in diabetes mellitus. Somatosensory and motor evoked potentials and spinal conduction time in diabetes mellitus” at the Department of Neurology, University Hospital of Comenius University, Bratislava in 2005. They compared 20 diagnosed diabetic patients aged 35-50 years with the control group of 30 healthy non-diabetic individuals. They stimulated the median and fibular nerve bilaterally with intensity 20mA, duration 0.1 ms and frequency 5 Hz for somatosensory evoked potentials (SSEPs) and recorded potentials from cerebral sensory cortex by placing electrodes according to 10-20 international system. They measured peripheral and central conduction time (PCT and CCT) as well as latencies. Motor evoked potentials (MEPs) were recorded from extensor digitorum brevis and first dorsal interosseous muscle by placing surface electrodes. They found that both peripheral and central conduction times were extended in the diabetic group. They assumed these changes are due to a smaller number of myelinated fibres. So, they concluded diabetes affects the myelin sheath and cause unapparent spinal cord lesions (Kucera et al., 2005).37 M00646922 MIDDLESEX UNIVERSITY 7. The aim of the study: The study aimed to inspect the effect of diabetes mellitus on intraoperative monitoring of somatosensory evoked potentials and motor evoked potentials during scoliosis surgery. 8. Hypothesis: The separate hypothesis was made for Amplitude (µV) and onset latency (ms). Null hypothesis (Ho) = Diabetes Mellitus cannot lead to decrease in amplitude (µV) during intraoperative monitoring of scoliosis correction surgery. Alternative hypothesis (H?) = Diabetes Mellitus can lead to decrease in amplitude (µV) during intraoperative monitoring of scoliosis correction surgery. Null hypothesis (Ho) = Diabetes Mellitus cannot lead to increase in onset latency (ms) during intraoperative monitoring of scoliosis correction surgery. Alternative hypothesis (H?) = Diabetes Mellitus can lead to increase in onset latency (ms) during intraoperative monitoring of scoliosis correction surgery.38 M00646922 MIDDLESEX UNIVERSITY SECTION-II39 M00646922 MIDDLESEX UNIVERSITY MATERIALS AND METHODS: 1. Study Design: “Retrospective Cohort Study Design” was used during this study. A retrospective cohort study or historical cohort study design is an analytical, observational longitudinal cohort study design usually used in medical research. A cohort (group) of patients with similar baseline characteristics and a risk factor is compared with another cohort (group) of individuals without risk factor to determine the impact of the risk factor on the incidence of the condition such as disease. These studies are carried out in present time, but data was taken from the past events and reconstructed to examine the medical outcomes. In this study cohort of the patients who underwent scoliosis correction surgery with a risk factor for diabetes mellitus were compared with the group of the individuals who experienced scoliosis correction surgery without diabetes mellitus. The advantage of using this study design is we can calculate the rate of disease over time, can collect the data about a sequence of events and its virtuous for inspecting unfamiliar experience. The disadvantage is we have less control over variables and to some extent, this design is susceptible to information or recalls bias (Song and Chung, 2010, Lwanga et al., 1991). 2. Sampling Technique: “Non-probability Convenience Sampling Technique” was used to gather a sample for this study. Non-probability convenience sampling technique is the opposite to the probability sampling. We do not calculate the odds of the members being selected for a sample and sample data is collected somewhere convenient to the researcher. The advantage of this sampling technique is its very time and cost effective as well as easy to use, and disadvantage is it’s almost impossible to represent the population well. 3. Study Setting: This study was conducted at the “Orthopaedic & Spine Centre Ghurki Trust Teaching Hospital Lahore, Pakistan”. Ethical consent was granted from the ethical committee of the Ghurki Trust Teaching Hospital before the commencement of this study. The ethical approval letter is attached in the appendix.40 M00646922 MIDDLESEX UNIVERSITY 4. Study Duration: The total time frame for this study was three months including six weeks of data collection. 5. Sample Size Estimation: The sample size was premeditated by using the World Health Organization (WHO) software. The sample size (n) calculated was twenty-six (26). The formula used for estimation of sample size is given below (Kasiulevi?ius et al., 2006, Song and Chung, 2010). (Sample Size determination in health studies version 2.0.21 WHO (Lwanga et al., 1991). 6. Sample Selection Criteria: Sample selection criteria were made before the commencement of this study. Patients were allocated into two groups including Diabetic group and Non-Diabetic group. Inclusion and exclusion criteria were defined. Patients with age between three (3) years to thirty (30) years were included in the study and patients below age three (3) years and above thirty (30) years were excluded from the study. The reason was that under age three (3) the somatosensory and motor evoked potentials pathways are not adequately developed and patients above age thirty (30) years are more likely to be present with comorbidities which can affect the somatosensory and motor evoked potentials. Both male and female patients were contained within in the study. Types of scoliosis were defined, and patients with idiopathic scoliosis and congenital scoliosis were included in the study. All patients with neuromuscular scoliosis were excluded from the study because in neuromuscular scoliosis both somatosensory and motor evoked potentials are already compromised which can cause false positive results. Types of the diabetes mellitus were also evaluated for sample selection criteria. Patients with Type-I41 M00646922 MIDDLESEX UNIVERSITY and Type-II diabetes mellitus were included in the study and patients with gestational diabetes were excluded from the study. Total Intravenous Anesthesia (TIVA) and halogenated agents along with analgesics were included as anaesthesia during the surgery in the study because they are usually used during scoliosis correction surgery to allow intraoperative monitoring to detect any possible injury. Propofol and Remifentanil in TIVA and Isoflurane, Sevoflurane and Desflurane etc. as an inhalational agent were used with mean alveolar concentration (MAC) less than 0.5. Inhalational agents with MAC value more than 0.5 can alter the somatosensory and motor evoked potentials. Neuromuscular blocking agents, e.g. Pancuronium, Rocuronium, Atracurium etc. were treated as exclusion criteria because they can cause blockage of nerve impulse transmission at the neuromuscular junction leading to complete blockage of motor evoked potentials. Patients with all diverse types of scoliosis curvatures were included in the study, for example, Kyphoscoliosis and lumbosacral scoliosis. Patients with any comorbidities, e.g. peripheral neuropathies, neuromuscular disorders, myopathies etc. which can disturb the amplitude and onset latency of somatosensory and motor evoked potentials were excluded from the study. Each patient history and data was strictly assessed for the inclusion and exclusion criteria before including in the study. Table 1: Sample selection criteria. Inclusion Criteria Exclusion Criteria Age Age between 3 to 30 years Above 30 years and below three years Gender Both male and female nil Scoliosis Idiopathic and congenital scoliosis Neuromuscular Scoliosis Diabetes Type-1 and Type-2 diabetes Gestational diabetes Anaesthesia Propofol (TIVA), Analgesics and Halogenated agents, e.g. Sevoflurane with MAC < 0.5 Neuromuscular blockers Curvature Kyphoscoliosis, lumbar scoliosis nil Comorbidities nil Peripheral neuropathies and myopathies42 M00646922 MIDDLESEX UNIVERSITY 7. Ethical Consideration: Ethical consent was granted from the “Ethical review committee” (ERC) of the Ghurki Trust Teaching Hospital as well as from Middlesex University. Both letters are attached in the appendix section. Patients personal information was not needed or used at any time during this study. 8. Methodology and material used: Last five (5) years somatosensory and motor evoked potentials (SSEPs & MEPs) data in the form of amplitude and onset latency were collected from the Neurophysiology department of the Orthopedic & Spine Centre Ghurki Trust Teaching Hospital Lahore, Pakistan. Twenty-six (26) patients were included in the study. Two groups were made, thirteen (13) patients who underwent scoliosis correction surgery with diabetes were allocated into a Diabetic group (DM group). Thirteen (13) patients who experienced scoliosis correction surgery and were non-diabetic, were included into a Non-Diabetic group (N-DM group). Each patient was assessed for sample selection criteria. The patient was prepared for the scoliosis correction surgery and taken into an anaesthetic room. Propofol was injected intravenously for deep sleep, and remifentanil was used to suppress the surgical pain. Electrodes are placed inside the anaesthetic room. A bite blocker was inserted in the mouth to avoid any injury to the tongue, and the patient was positioned prone on the surgical table. Somatosensory evoked potentials (SSEPs) were recorded by stimulating bilateral median nerve (MNº) in upper limb and bilateral posterior tibial nerve (PTNº) in the lower leg. Surface electrodes were placed at the frontal surface of the wrist just proximal to the carpal tunnel for median nerve somatosensory evoked potentials. Similarly, surface electrodes were placed behind the medial malleolus of the tibia bone just near the foot where the posterior tibial nerve is superficial to stimulate the nerve for somatosensory evoked potentials. Somatosensory evoked potentials were recorded from the sensory cortex of the brain by inserting corkscrew electrodes in the scalp at prefrontal region (Fpz), the central region (Cz) and sensory area 3-4 cm lateral to the central region (C3 & C4). The stimulation parameters were within the frequency of 3 to 5 Hz with 0.2 to 300 ms duration and intensity of 20 mA for upper limb and 30 mA for lower limb. Median and posterior tibial43 M00646922 MIDDLESEX UNIVERSITY nerves were stimulated, and somatosensory evoked potentials were recorded in the form of somatosensory nerve action potentials (SNAPs) as a baseline recording before the commencement of the surgery. The figure 14 below is displaying distinct types of electrodes which we used during intraoperative monitoring of the scoliosis correction surgery. The blue electrode is a corkscrew electrode which was used at the cortical region for stimulation of motor evoked potentials and recording of somatosensory evoked potentials. Electrode with yellow and black wires is a needle electrode which is inserted into the muscles and was used for recording of compound muscle action potential (CMAP) from the muscles. The depiction in the middle is a surface electrode which was used for stimulation of median and posterior tibial nerves. And the last photograph is depicting the placement of the corkscrew electrodes according to the 10-20 international system for somatosensory evoked potentials recording site, and motor evoked potentials stimulating site.44 M00646922 MIDDLESEX UNIVERSITY Figure 14: Corkscrew, surface electrodes, needle electrodes and placement of corkscrew electrodes according to 10-20 international system.45 M00646922 MIDDLESEX UNIVERSITY The figure 15-A below is depicting the stimulation site (median nerve) and recording sites (Fz-C3′), Cervical (C5) and Erb’s (EP) for upper limb somatosensory evoked potentials (SSEPs). Similarly, figure 15-B is illustrating the stimulation site (posterior tibial nerve) at popliteal fossa and recording site (Fz-C4′), Thoracic (T6 ; 12) and Lumbar (L3) for lower limb somatosensory evoked potentials. Figure 15: Stimulation and recording sites of somatosensory evoked potentials (Singh, 2016).46 M00646922 MIDDLESEX UNIVERSITY Motor Evoked potentials (MEPs) were recorded from the four muscle groups bilaterally. Needle electrodes were placed inside abductor pollicis brevis (APB) for upper limb and tibialis posterior (TA), abductor hallucis (AH) and quadriceps (QUAD) for lower limb muscles. Corkscrew electrodes were placed inside the scalp above the motor cortex for stimulation. Stimulation intensity of the MEPs varies from 250V to 750V with duration of each pulse between 0.5 to 3 ms and inter-stimulus interval of 1-5 ms. The frequency of MEPs was kept as 0.5 to 2 Hz because there was no need for averaging for muscle MEPs. Motor cortex was stimulated to record the compound muscle action potentials (CMAP) from the all muscle groups as a baseline. When surgery was commenced, free run electromyography (EMG) was used to detect any potential injury to the nerve root in the form of burst or spike. Two channel free run electroencephalography (EEG) was used to keep an eye on the sleep status of the patient. Both sensory nerves and motor cortex were stimulated throughout the surgery at different intervals to record somatosensory and motor evoked potentials waveform to avoid any potential harm to the patients. Both remifentanil and propofol were maintained as trans intravenous anaesthesia (TIVA). Patient temperature, blood pressure, heart rate and pulse were recorded after every 15 minutes interval to correlate any change in the SSEPs or MEPs waveforms. After completion of the operation, closing MEPs and SSEPs were recorded. All twenty-six (26) cases underwent the same surgical procedure of scoliosis correction surgery with the same conditions. 9. Data Collection and Data Analysis: Amplitude in microvolts (µV) and onset latency in milliseconds (ms) was measured from baseline as well as from closing waveforms of both somatosensory and motor evoked potentials. Amplitude (figure-16) is a peak to peak value between the positive peak and negative peak of the action potential which represents the number of the conducting fibres. Onset latency (figure-16) is a measurement of the conductivity time of the fastest fibres from the stimulation site to the recording electrodes. Data was presented in the form of tables for both Diabetic (DM) and Non-Diabetic (N-DM) groups. Data of median and posterior tibial nerve SSEPs and muscle MEPs is given in the appendix in tabulated form. The figure below is representing how to measure onset latency (OL) and amplitude (amp).47 M00646922 MIDDLESEX UNIVERSITY Figure 16: Measurement method for amplitude and onset latency (OL). After completion of data collection, data were analysed by using Minitab 17 statistical software to test the hypothesis. The null hypothesis of the study was that diabetes mellitus could not lead to increase in onset latency and decrease in amplitude during intraoperative monitoring of scoliosis correction surgery. And alternative hypothesis (H?) was that Diabetes Mellitus could lead to increase in onset latency and decrease in amplitude during intraoperative monitoring of scoliosis correction surgery. To test this hypothesis, new questions were established and analysed by creating a new hypothesis. Based on the results of the new hypothesis central hypothesis was tested in the end. To find out the difference in baseline amplitude and onset latency from the closing amplitude and onset latency a hypothesis was made to compare baseline amplitude with closing amplitude and baseline onset latency with a closing onset latency of the median and posterior tibial nerves of the diabetic group as well as for the non-diabetic group. Null hypothesis (Ho) was there is no difference between baseline and closing amplitude while the alternative hypothesis (H?) was there is the difference between the baseline and the closing amplitude of SSEPs. A similar hypothesis was made for onset latency also in which null hypothesis (Ho) was there is no difference between baseline and closing onset latency while alternative hypothesis (H?) was there is the difference between baseline and closing onset latency of SSEPs. Data were analysed for the differences by plotting boxplot to get the mean values. Because data was not time series and consisted of two groups with dependent samples between the groups, normal distribution was confirmed. A significance level of 0.05 was defined and a paired T-test was applied for normally distributed data, and Wilcoxon Signed Rank test was administered on ranked differences of data which was not normally distributed. P-value was used to define the results if P ? (0.05) then we believed on null hypothesis (Ho) which was there is no difference. Correspondingly, to find out differences in baseline amplitude and onset latency from closing amplitude and onset latency of motor evoked potentials (MEPs) a hypothesis was made for all muscle group. Null hypothesis (Ho) was there is no difference in baseline and closing amplitude and the alternative hypothesis (H?) was there is the difference between the baseline and closing amplitude of MEPs. Likewise, for onset latency null hypothesis (Ho) was there is no difference between baseline and closing onset latency and the alternative hypothesis (H?) was there is the difference between baseline and closing onset latency of MEPs. Data were analyzed for the differences by plottingng boxplot to get the mean values. Because data was not time series and consisted of two groups with dependent samples between the groups, normal distribution was confirmed. A significance level of 0.05 was defined, and a paired T-test was applied for normally distributed data, and Wilcoxon Signed Rank test was applied on ranked differences of data which was not normally distributed. P-value was used to define the results if P ? (0.05) then we believed on null hypothesis (Ho) which was there is no difference. Figure 17: Flowchart for analysis of the difference between interdependent data. Analysis of Difference Yes Have Means Yes Time Series data No Two Groups Yes Samples are dependent in the groups Yes Normal Distribution Yes Paired T-test ? = 0.05 NO Wilcoxon Signed Rank Test49 M00646922 MIDDLESEX UNIVERSITY The main hypothesis was analyzed by comparing diabetic baseline amplitude and onset latency with the non-diabetic baseline amplitude. Likewise, closing amplitude and onset latency of the diabetic group was compared with the closing amplitude and onset latency of the non-diabetic group both for somatosensory and motor evoked potentials. The hypothesis was tested for the difference by plotting boxplot to get the mean values. Data was not time series and was consisted of two groups with samples independent between the groups. Normal distribution and equal variance were confirmed. Two-Sample T-test was applied on data with equal variance and normal distribution, and Mann Whitney test was administered on data with unequal variance and not normally distributed. A significance level of 0.05 was defined. P-value was used to determine the results if P ? (0.05) then we believed on null hypothesis (Ho) which was that Diabetes Mellitus could not lead to significant increase in onset latency and a significant decrease in amplitude during intraoperative monitoring of scoliosis correction surgery. Figure 18: Flow Chart for an analysis of the difference between independent data. Analysis of Difference Yes Have Means Yes Time Series data No Two Groups Yes Samples are dependent in the groups No Normal Distribution and Equal Variance Yes Two Sample T-test NO Mann Whitney50 M00646922 MIDDLESEX UNIVERSITY SECTION-III51 M00646922 MIDDLESEX UNIVERSITY RESULTS: 1. Percentage of gender distribution in sample size: 26 patients were enrolled in the study which was consisted of 15 (58%) females and 11 (42%) males. The percentage of male to female is given below in the form of the pie chart. Figure 19: Pie chart for percentage of gender distribution in sample size. Female58%Male42%Percentage of Male and FemaleFemaleMale52 M00646922 MIDDLESEX UNIVERSITY 2. The frequency of gender distribution in the groups: Out of 26 patients, 13 patients were enrolled in the diabetic group, and 13 patients were allocated in the non-diabetic group. The diabetic group consisted of 6 males and seven females while the non-diabetic group consisted of 5 males and eight females. The bar chart below is depicting this gender distribution below. Figure 20: Bar chart for gender distribution among groups. 65780123456789DiabeticNon-DiabeticGender distribution among groups MaleFemale53 M00646922 MIDDLESEX UNIVERSITY 3. Patients distribution in different age groups: Inclusion criteria for the age were 03 years to 30 years. All 26 patients were distributed among different age groups. The mean age calculated was 16.19 with a standard deviation of 6.91. The range of the age was minimum six years and maximum 28 years. Four (4) patients were between 03-07 years, five (5) patients were between 08-12 years, and five (5) patients were between 13-17 years. Age group 18-22 years and 23-30 years consisted of six (6) patients in each group. The bar chart below is displaying this age distribution among different age groups. Figure 21: Bar chart is representing age groups. 4556601234567FrequencyAge Groups 03-07 years08-12 years13-17 years18-22 years23-30 years54 M00646922 MIDDLESEX UNIVERSITY 4. Patients distribution in age groups according to diagnosis: Patients were distributed among groups using non-probability convenience sampling. Group 03-07 years had one diabetic and three non-diabetic patients. Group 08-12 had three ; two; group 13-17 had two and three, group 18-22 years had three in each and group 23-30 years had four diabetic and two non-diabetic respectively. Figure 22: Bar chart illustrating age distribution according to diagnosis. 132343233200.511.522.533.544.5 03-07 years08-12 years13-17 years18-22 years23-30 yearsAge distribution according to diagnosisDiabeticNon-Diabetic55 M00646922 MIDDLESEX UNIVERSITY 5. Question 1: Difference between baseline and closing SSEPs of Median nerve among the non-diabetic group? P-value was used to define the results when P ? (0.05) we believed on null hypothesis (Ho) which was there is no difference. 5.1- Non-diabetic group median nerve SSEPs amplitude (amp): Null hypothesis (Ho) = There is no difference between baseline and closing amplitude of median nerve among the non-diabetic group. Alternative hypothesis (H?) = There is the difference between baseline and closing amplitude of median nerve among the non-diabetic group. Baseline amplitude of the median nerve was compared with the closing amplitude of the median nerve of the same group. The table below is demonstrating that a paired T-test was used for both rights and left median nerve (RMN ; LMN) SSEPs. Paired T-test was used because we were analyzing difference with data which was not time series but had means, two groups, interdependent samples and normal distribution. For the right median nerve channel one (Fpz-C3) we accepted the null hypothesis because of P ; ? (0.05). For right median nerve channel two and left median nerve both channels we rejected the null hypothesis and accepted alternative hypothesis because of P ; ? (0.05).56 M00646922 MIDDLESEX UNIVERSITY Table 2: Non-Diabetic group Right and left median nerve (RMN ; LMN) SSEPs amplitude difference: Median Nerve SSEPs Amplitude (µ?) Difference Baseline Vs Closing Non-Diabetic Group Mean St Dev Normality Test P- Value Statistical Test P-Value of Statistical Test % Change In Amplitude baseline Vs Closing Significance P ? = Ho Channel 1: (Fpz-C3) RMN Baseline 4.469 0.772 0.068 Paired T-Test T= -1.90 P – Value 0.082 3.11% P ; ? = Ho RMN Closing 4.608 0.710 0.110 Channel 2: (C3-C4) RMN Baseline 4.092 0.755 0.621 Paired T-test T= -4.39 P – Value 0.001 5.08 % P ; ? = H1 RMN Closing (C3-C4) 4.300 0.805 0.398 Channel 1: (Fpz-C3) LMN Baseline 4.285 0.894 0.143 Paired T-test T= – 2.29 P – Value 0.041 3.22% P ; ? = H1 LMN Closing (Fpz-C3) 4.423 0.901 0.230 Channel 2: (C3-C4) LMN Baseline 3.908 1.124 0.471 Paired T-test T= – 4.76 P – Value 0.000 5.70% P ? (0.05). Table 3: Non-Diabetic right and left group median nerve (RMN ; LMN) SSEPs onset latency difference: Median Nerve SSEPs Onset Latency (ms) Difference Baseline Vs Closing Non-Diabetic Group Mean St Dev Normality Test P- Value Statistical Test P-Value of Statistical Test % Change In Amplitude baseline Vs Closing Significance P ? = Ho Channel 1: (Fpz-C3) RMN Baseline 15.838 2.372 0.635 Paired T-Test T= -2.16 P – Value 0.051 0.93% P ; ? = Ho RMN Closing 15.985 2.509 0.691 Channel 2: (C3-C4) RMN Baseline 15.346 1.909 0.471 Paired T-test T= -1.02 P – Value 0.329 0.55 % P ; ? = Ho RMN Closing 15.431 2.039 0.510 Channel 1: (Fpz-C3) LMN Baseline 14.60 1.892 0.399 Paired T-test T= – 2.76 P – Value 0.017 1.21% P ; ? = Ho LMN Closing 14.785 2.037 0.352 Channel 2: (C3-C4) LMN Baseline 14.462 2.422 0.814 Paired T-test T= – 2.40 P – Value 0.034 1.49% P ; ? = Ho LMN Closing 14.677 2.385 0.87658 M00646922 MIDDLESEX UNIVERSITY 6. Question 2: Difference between baseline and closing SSEPs of Posterior Tibial nerve among the non-diabetic group? P-value was used to define the results when P ? (0.05) we believed on null hypothesis (Ho) which was there is no difference. 6.1- Non- diabetic group posterior tibial nerve SSEPs amplitude (amp): Null hypothesis (Ho) = There is no difference between baseline and closing amplitude of posterior tibial nerve among the non-diabetic group. Alternative hypothesis (H?) = There is the difference between baseline and closing amplitude of posterior tibial nerve among the non-diabetic group. Baseline amplitude of the posterior tibial nerve was compared with the closing amplitude of the posterior tibial nerve of the same group. The table below is elaborating that Wilcoxon Signed Rank test was applied for channel one (Cz-Fpz) of both rights and left tibial nerve (RTN ; LTN) because we were analyzing difference for the data which was not time series but have means, two groups, interdependent samples and non-normal distributed. Paired T-test was applied for channel two (C4-C3) of both rights and left tibial nerve (RTN ; LTN) because we were analyzing difference with data which was not time series but had means, two groups, interdependent samples and normal distribution. For both channels of right median nerve as well as left median nerve we accepted the null hypothesis because of P ; ? (0.05).59 M00646922 MIDDLESEX UNIVERSITY Table 4: Non-Diabetic group right and left posterior tibial nerve (RTN ; LTN) SSEPs amplitude difference: Posterior Tibial Nerve SSEPs Amplitude (µ?) Difference Baseline Vs Closing Non-Diabetic Group Mean St Dev Normality Test P- Value Statistical Test P-Value of Statistical Test % Change In Amplitude baseline Vs Closing Significance P ? = Ho Channel 1: (Cz-Fpz) RTN Baseline 4.454 0.732 0.034 Wilcoxon Signed Rank M= -0.05 P – Value 0.374 0.67% P ; ? = Ho RTN Closing 4.485 0.719 0.018 Channel 2: (C4-C3) RTN Baseline 4.185 0.689 0.229 Paired T-test T= -0.69 P – Value 0.502 0.72 % P ; ? = Ho RTN Closing 4.215 0.746 0.089 Channel 1: (Cz-Fpz) LTN Baseline 4.246 1.094 0.007 Wilcoxon Signed Rank M= 0.00 P – Value 0.592 0.54% P ; ? = Ho LTN Closing 4.269 0.863 0.012 Channel 2: (C4-C3) LTN Baseline 4.031 0.857 0.448 Paired T-test T= – 1.43 P – Value 0.180 1.51% P ; ? = Ho LTN Closing 4.092 0.877 0.194 6.2- Non-diabetic group posterior tibial nerve SSEPs onset latency (OL): Null hypothesis (Ho) = There is no difference between baseline and closing onset latency of the posterior tibial nerve among the non-diabetic group. Alternative hypothesis (H?) = There is the difference between baseline and closing onset latency of the posterior tibial nerve among the non-diabetic group. Baseline onset latency of the posterior tibial nerve was compared with the closing onset latency of the posterior tibial nerve of the same group. The table below is signifying that the60 M00646922 MIDDLESEX UNIVERSITY paired T-test was used for both channels of the right posterior tibial nerve (RTN) SSEPs. Paired T-test was used because we were analyzing difference with data which was not time series but had means, two groups, interdependent samples and normal distribution. And Wilcoxon Signed Rank test was applied for both channels of left tibial nerve (LTN) because we were analyzing difference for the data which was not time series but have means, two groups, interdependent samples and non-normal distributed. For both channels of right median nerve as well as left median nerve we accepted the null hypothesis because of P ; ? (0.05). Table 5: Non-Diabetic group right and left posterior tibial nerve (RTN ; LTN) SSEPs onset latency difference: Posterior Tibial Nerve SSEPs Onset Latency (ms) Difference Baseline Vs Closing Non-Diabetic Group Mean St Dev Normality Test P- Value Statistical Test P-Value of Statistical Test % Change In Amplitude baseline Vs Closing Significance P ? = Ho Channel 1: (Cz-Fpz) RTN Baseline 25.78 4.371 0.059 Paired T-Test T= -0.51 P – Value 0.621 0.12% P ; ? = Ho RTN Closing 25.81 4.305 0.105 Channel 2: (C4-C3) RTN Baseline 25.37 4.332 0.098 Paired T-test T= -0.72 P – Value 0.487 0.12 % P ; ? = Ho RTN Closing 25.40 4.245 0.090 Channel 1: (Cz-Fpz) LTN Baseline 24.90 4.796 0.045 Wilcoxon Signed Rank M= -0.05 P – Value 0.625 0.12% P ; ? = Ho LTN Closing 24.93 4.868 0.05 Channel 2: (C4-C3) LTN Baseline 25.16 4.680 0.005 Wilcoxon Signed Rank M= 0.05 P – Value 0.683 -0.04% P ; ? = Ho LTN Closing 25.15 4.616 0.07761 M00646922 MIDDLESEX UNIVERSITY 7. Question 3: Difference between baseline and closing SSEPs of Median nerve among the diabetic group? P-value was used to define the results when P ? (0.05) we believed on null hypothesis (Ho) which was there is no difference. 7.1- Diabetic group median nerve SSEPs amplitude (amp): Null hypothesis (Ho) = There is no difference between baseline and closing amplitude of median nerve among the diabetic group. Alternative hypothesis (H?) = There is the difference between baseline and closing amplitude of median nerve among the diabetic group. Baseline amplitude of the median nerve was compared with the closing amplitude of the median nerve of the same group. The table below is demonstrating that a paired T-test was used for both rights and left median nerve (RMN ; LMN) SSEPs. Paired T-test was used because we were analyzing difference with data which was not time series but had means, two groups, interdependent samples and normal distribution. For both channels of right and left median nerve we rejected the null hypothesis and accepted alternative hypothesis because of P ; ? (0.05).62 M00646922 MIDDLESEX UNIVERSITY Table 6: Diabetic group right and left median nerve (RMN ; LMN) SSEPs amplitude difference: Median Nerve SSEPs Amplitude (µ?) Difference Baseline Vs Closing Diabetic Group Mean St Dev Normality Test P- Value Statistical Test P-Value of Statistical Test % Change In Amplitude baseline Vs Closing Significance P ? = Ho Channel 1: (Fpz-C3) RMN Baseline 2.738 0.837 0.848 Paired T-test T= 4.11 P – Value 0.001 -11.79% P ; ? = H1 RMN Closing 2.415 0.838 0.765 Channel 2: (C3-C4) RMN Baseline 2.762 0.781 0.895 Paired T-test T= 5.51 P – Value 0.000 -13.11% P ; ? = H1 RMN Closing 2.400 0.825 0.301 Channel 1: (Fpz-C3) LMN Baseline 2.846 1.162 0.461 Paired T-test T= 4.20 P – Value 0.001 -14.87% P ; ? = H1 LMN Closing 2.423 0.985 0.955 Channel 2: (C3-C4) LMN Baseline 2.777 1.061 0.793 Paired T-test T= 6.20 P – Value 0.000 -13.03% P ; ? = H1 LMN Closing 2.415 1.002 0.353 7.2- Diabetic group median nerve SSEPs onset latency (OL): Null hypothesis (Ho) = There is no difference between baseline and closing onset latency of the median nerve among the diabetic group. Alternative hypothesis (H?) = There is the difference between baseline and closing onset latency of the median nerve among the diabetic group. Baseline onset latency of the median nerve was compared with the closing onset latency of the median nerve of the same group. The table below is demonstrating that a paired T-test63 M00646922 MIDDLESEX UNIVERSITY was used for both rights and left median nerve (RMN ; LMN) SSEPs. Paired T-test was used because we were analyzing difference with data which was not time series but had means, two groups, interdependent samples and normal distribution. For both channels of right and left median nerve we rejected the null hypothesis and accepted alternative hypothesis because of P ; ? (0.05). Table 7: Diabetic group right and left median nerve (RMN ; LMN) SSEPs onset latency difference: Median Nerve SSEPs Onset Latency (ms) Difference Baseline Vs Closing Diabetic Group Mean St Dev Normality Test P- Value Statistical Test P-Value of Statistical Test % Change In Amplitude baseline Vs Closing Significance P ? = Ho Channel 1: (Fpz-C3) RMN Baseline 15.308 2.018 0.609 Paired T-test T= -4.36 P – Value 0.001 7.04% P ; ? = H1 RMN Closing 16.385 2.688 0.177 Channel 2: (C3-C4) RMN Baseline 15.000 2.256 0.668 Paired T-test T= -5.35 P – Value 0.000 8.00% P ; ? = H1 RMN Closing 16.200 2.769 0.878 Channel 1: (Fpz-C3) LMN Baseline 15.177 2.146 0.679 Paired T-test T= -4.56 P – Value 0.001 9.43% P ; ? = H1 LMN Closing 16.608 2.885 0.755 Channel 2: (C3-C4) LMN Baseline 15.092 2.390 0.717 Paired T-test T= -4.62 P – Value 0.001 10.14% P ; ? = H1 LMN Closing 16.623 3.346 0.14664 M00646922 MIDDLESEX UNIVERSITY 8. Question 4: Difference between baseline and closing SSEPs of Posterior Tibial nerve among the diabetic group? P-value was used to define the results when P ? (0.05) we believed on null hypothesis (Ho) which was there is no difference. 8.1- Diabetic group posterior tibial nerve SSEPs amplitude (amp): Null hypothesis (Ho) = There is no difference between baseline and closing amplitude of posterior tibial nerve among the diabetic group. Alternative hypothesis (H?) = There is the difference between baseline and closing amplitude of posterior tibial nerve among the diabetic group. Baseline amplitude of the posterior tibial nerve was compared with the closing amplitude of the posterior tibial nerve of the same group. The table below is demonstrating that a paired T-test was used for both rights and left posterior tibial nerve (RTN ; LTN) SSEPs. Paired T-test was used because we were analyzing difference with data which was not time series but had means, two groups, interdependent samples and normal distribution. For both channels of right and left median nerve we rejected the null hypothesis and accepted alternative hypothesis because of P ; ? (0.05).65 M00646922 MIDDLESEX UNIVERSITY Table 8: Diabetic group right and left posterior tibial nerve (RTN ; LTN) SSEPs amplitude difference: Posterior Tibial Nerve SSEPs Amplitude (µ?) Difference Baseline Vs Closing Diabetic Group Mean St Dev Normality Test P- Value Statistical Test P-Value of Statistical Test % Change In Amplitude baseline Vs Closing Significance P ? = Ho Channel 1: (Cz-Fpz) RTN Baseline 2.938 0.856 0.238 Paired T-test T= 5.38 P – Value 0.000 -15.18% P ; ? = H1 RTN Closing 2.492 0.786 0.306 Channel 2: (C4-C3) RTN Baseline 2.885 0.815 0.138 Paired T-test T= 5.90 P – Value 0.000 -14.66% P ; ? = H1 RTN Closing 2.462 0.699 0.058 Channel 1: (Cz-Fpz) LTN Baseline 3.362 1.094 0.235 Paired T-test T= 7.10 P – Value 0.000 -14.19% P ; ? = H1 LTN Closing 2.885 1.078 0.118 Channel 2: (C4-C3) LTN Baseline 2.969 1.061 0.708 Paired T-test T= 5.25 P – Value 0.000 -13.98% P ; ? = H1 LTN Closing 2.554 0.935 0.757 8.2- Diabetic group posterior tibial nerve SSEPs onset latency (OL): Null hypothesis (Ho) = There is no difference between baseline and closing onset latency of the posterior tibial nerve among the diabetic group. Alternative hypothesis (H?) = There is the difference between baseline and closing onset latency of the posterior tibial nerve among the diabetic group. Baseline onset latency of the posterior tibial nerve was compared with the closing onset latency of the posterior tibial nerve of the same group. The table below is elaborating that Wilcoxon Signed Rank test was applied for both channels of right and left tibial nerve (RTN ; LTN) because we were analyzing difference for the data which was not time series but have66 M00646922 MIDDLESEX UNIVERSITY means, two groups, interdependent samples and non-normal distributed. For both channels of right and left median nerve we rejected the null hypothesis and accepted alternative hypothesis because of P ; ? (0.05). Table 9: Diabetic group right and left posterior tibial nerve (RTN ; LTN) SSEPs onset latency difference: Posterior Tibial Nerve SSEPs Onset Latency (ms) Difference Baseline Vs Closing Diabetic Group Mean St Dev Normality Test P- Value Statistical Test P-Value of Statistical Test % Change In Amplitude baseline Vs Closing Significance P ? = Ho Channel 1: (Cz-Fpz) RTN Baseline 27.48 3.536 0.018 Wilcoxon Signed Rank M= -0.70 P – Value 0.002 2.98% P ; ? = H1 RTN Closing 28.3 3.309 0.034 Channel 2: (C4-C3) RTN Baseline 28.18 2.558 0.017 Wilcoxon Signed Rank M= -0.65 P – Value 0.002 2.45% P ; ? = H1 RTN Closing 28.87 2.629 0.009 Channel 1: (Cz-Fpz) LTN Baseline 27.72 3.088 0.005 Wilcoxon Signed Rank M= -0.65 P – Value 0.002 2.31% P ; ? = H1 LTN Closing 28.36 3.133 0.005 Channel 2: (C4-C3) LTN Baseline 28.08 2.749 0.072 Wilcoxon Signed Rank M= -0.65 P – Value 0.002 2.28% P ; ? = H1 LTN Closing 28.72 2.787 0.00567 M00646922 MIDDLESEX UNIVERSITY 9. Question 5: Difference between baseline and closing MEPs among the non-diabetic group? P-value was used to define the results when P ? (0.05) we believed on null hypothesis (Ho) which was there is no difference. 9.1- Non-diabetic group MEPs amplitude (amp): Null hypothesis (Ho) = There is no difference between baseline and closing amplitude of MEPs among the non-diabetic group. Alternative hypothesis (H?) = There is the difference between baseline and closing amplitude among the non-diabetic group. Baseline amplitude of the right and left abductor pollicis brevis (APB), tibialis anterior (TA), abductor hallucis (AH) and quadriceps (QUAD) were compared with the closing amplitude of the right and left abductor pollicis brevis (APB), tibialis anterior (TA), abductor hallucis (AH) and quadriceps (QUAD) of the same group. The table below is displaying paired T-test applied for L-APB, L-TA and R-AH. Paired T-test was used because we were analyzing difference with data which was not time series but had means, two groups, interdependent samples and normal distribution. Wilcoxon Signed Rank test was applied for R-APB, R-TA, L-AH, R-QUAD and L-QUAD because we were analyzing difference for the data which was not time series but have means, two groups, interdependent samples and non-normal distributed. We rejected the null hypothesis and accepted alternative hypothesis for all muscle groups because of P ? (0.05).68 M00646922 MIDDLESEX UNIVERSITY Table 10: Non-Diabetic MEPs amplitude difference: MEPs Amplitude (µ?) Difference Baseline Vs Closing Non-Diabetic Group Mean St Dev Normality Test P- Value Statistical Test P-Value of Statistical Test % Change In Amplitude baseline Vs Closing Significance P ? = Ho R-APB Baseline 142.5 16.41 0.030 Wilcoxon Signed Rank M= 7.250 P – Value 0.02 0.77% P ; ? = H1 R-APB Closing 143.6 17.74 0.007 L-APB Baseline 145.6 32.74 0.069 Paired T-test T= -2.35 P – Value 0.037 1.03 % P ; ? = H1 L-APB Closing 147.1 34.45 0.063 R-TA Baseline 125.4 42.16 0.006 Wilcoxon Signed Rank M= 7.250 P – Value 0.002 0.55% P ; ? = H1 R-TA Closing 126.1 42.37 0.009 L-TA Baseline 113.0 41.18 0.162 Paired T-test T= – 2.90 P – Value 0.013 0.44% P ? = Ho R-AH Closing 101.9 53.96 0.270 L-AH Baseline 121.7 55.79 0.019 Wilcoxon Signed Rank M= 7.00 P – Value 0.002 -0.82% P ; ? = H1 L-AH Closing 120.7 58.30 0.019 R-QUAD Baseline 89.44 53.76 0.011 Wilcoxon Signed Rank M= 7.250 P – Value 0.002 0.98% P ; ? = Ho R-QUAD Closing 90.32 52.78 0.009 L-QUAD Baseline 101.8 35.43 0.005 Wilcoxon Signed Rank M= 7.00 P – Value 0.002 0.39% P ; ? = H1 L-QUAD Closing 102.2 35.52 0.00569 M00646922 MIDDLESEX UNIVERSITY 9.2- Non-diabetic group MEPs onset latency (OL): Null hypothesis (Ho) = There is no difference between baseline and closing onset latency of MEPs among the non-diabetic group. Alternative hypothesis (H?) = There is the difference between baseline and closing onset latency among the non-diabetic group. Baseline onset latency of the right and left abductor pollicis brevis (APB), tibialis anterior (TA), abductor hallucis (AH) and quadriceps (QUAD) were compared with the closing onset latency of the right and left abductor pollicis brevis (APB), tibialis anterior (TA), abductor hallucis (AH) and quadriceps (QUAD) of the same group. The table below is exhibiting that paired T-test applied for R-APB, R-TA and L-TA. Paired T-test was used because we were analyzing difference with data which was not time series but had means, two groups, interdependent samples and normal distribution. Wilcoxon Signed Rank test was applied for L-APB, R-AH, L-AH, R-QUAD and L-QUAD because we were analyzing difference for the data which was not time series but have means, two groups, interdependent samples and non-normal distributed. We rejected the null hypothesis and accepted alternative hypothesis for R-APB, L-APB, L-TA, L-AH, R-QUAD and L-QUAD because of P ? (0.05).70 M00646922 MIDDLESEX UNIVERSITY Table 11: Non-Diabetic MEPs onset latency difference: MEPs Onset Latency (ms) Difference Baseline Vs Closing Non-Diabetic Group Mean St Dev Normality Test P- Value Statistical Test P-Value of Statistical Test % Change In Amplitude baseline Vs Closing Significance P ? = Ho R-APB Baseline 22.84 3.020 0.373 Paired T-test T= – 2.80 P – Value 0.016 0.39% P ; ? = H1 R-APB Closing 22.93 2.996 0.431 L-APB Baseline 23.22 3.803 0.005 Wilcoxon Signed Rank M= 6.750 P – Value 0.002 0.43 % P ? = Ho R-TA Closing 28.75 5.536 0.070 L-TA Baseline 27.72 3.807 0.060 Paired T-test T= – 2.55 P – Value 0.025 0.43% P ? = Ho R-AH Closing 36.69 8.339 0.006 L-AH Baseline 36.48 6.468 0.037 Wilcoxon Signed Rank M= 7.00 P – Value 0.002 9.40% P ; ? = H1 L-AH Closing 33.05 4.921 0.012 R-QUAD Baseline 24.42 4.535 0.028 Wilcoxon Signed Rank M= 7.00 P – Value 0.002 2.66% P ; ? = H1 R-QUAD Closing 25.07 4.906 0.025 L-QUAD Baseline 22.44 5.445 0.005 Wilcoxon Signed Rank M= 7.00 P – Value 0.002 0.76% P ; ? = H1 L-QUAD Closing 22.61 5.388 0.00571 M00646922 MIDDLESEX UNIVERSITY 10. Question 6: Difference between baseline and closing MEPs among the Diabetic group? P-value was used to define the results when P ? (0.05) we believed on null hypothesis (Ho) which was there is no difference. 10.1- Diabetic group MEPs amplitude (amp): Null hypothesis (Ho) = There is no difference between baseline and closing amplitude of MEPs among the diabetic group. Alternative hypothesis (H?) = There is the difference between baseline and closing amplitude among the diabetic group. Baseline amplitude of the right and left abductor pollicis brevis (APB), tibialis anterior (TA), abductor hallucis (AH) and quadriceps (QUAD) were compared with the closing amplitude of the right and left abductor pollicis brevis (APB), tibialis anterior (TA), abductor hallucis (AH) and quadriceps (QUAD) of the same group. The table below is displaying paired T-test applied to all muscle group. Paired T-test was used because we were analyzing difference with data which was not time series but had means, two groups, interdependent samples and normal distribution. We rejected the null hypothesis and accepted alternative hypothesis for all right and left muscle group because of P ; ? (0.05).72 M00646922 MIDDLESEX UNIVERSITY Table 12: Diabetic group MEPs amplitude difference: MEPs Amplitude (µ?) Difference Baseline Vs Closing Diabetic Group Mean St Dev Normality Test P- Value Statistical Test P-Value of Statistical Test % Change In Amplitude baseline Vs Closing Significance P ? = Ho R-APB Baseline 149.7 43.85 0.172 Paired T-test T= 3.91 P – Value 0.002 -5.47% P ; ? = H1 R-APB Closing 141.5 44.22 0.156 L-APB Baseline 150.5 44.57 0.261 Paired T-test T= 3.88 P – Value 0.002 -2.32% P ; ? = H1 L-APB Closing 147.0 44.27 0.176 R-TA Baseline 156.8 51.08 0.277 Paired T-test T= 2.53 P – Value 0.026 -4.46% P ; ? = H1 R-TA Closing 149.8 50.66 0.249 L-TA Baseline 158.9 46.44 0.285 Paired T-test T= 3.58 P – Value 0.004 -2.58% P ; ? = H1 L-TA Closing 154.8 46.16 0.244 R-AH Baseline 152.0 64.97 0.157 Paired T-test T= 2.03 P – Value 0.045 -13.49% P ; ? = H1 R-AH Closing 131.5 53.42 0.301 L-AH Baseline 151.3 58.31 0.084 Paired T-test T= 4.77 P – Value 0.000 -1.78% P ; ? = H1 L-AH Closing 148.6 59.06 0.062 R-QUAD Baseline 123.1 36.15 0.169 Paired T-test T= 5.76 P – Value 0.000 -2.35% P ; ? = H1 R-QUAD Closing 120.2 35.40 0.162 L-QUAD Baseline 132.9 43.85 0.230 Paired T-test T= 4.28 P – Value 0.001 -2.63% P ; ? = H1 L-QUAD Closing 129.4 43.73 0.17173 M00646922 MIDDLESEX UNIVERSITY 10.2- Diabetic group MEPs onset latency (OL): Null hypothesis (Ho) = There is no difference between baseline and closing onset latency of MEPs among the diabetic group. Alternative hypothesis (H?) = There is the difference between baseline and closing onset latency among the diabetic group. Baseline onset latency of the right and left abductor pollicis brevis (APB), tibialis anterior (TA), abductor hallucis (AH) and quadriceps (QUAD) were compared with the closing onset latency of the right and left abductor pollicis brevis (APB), tibialis anterior (TA), abductor hallucis (AH) and quadriceps (QUAD) of the same group. Wilcoxon Signed Rank test was applied to all muscle groups except R-AH because we were analyzing difference for the data which was not time series but have means, two groups, interdependent samples and non-normal distributed. Paired T-test was applied for R-AH because we were analyzing difference with data which was not time series but had means, two groups, interdependent samples and normal distribution. We rejected the null hypothesis and accepted alternative hypothesis for all right and left muscle group because of P ; ? (0.05).74 M00646922 MIDDLESEX UNIVERSITY Table 13: Diabetic group MEPs onset latency difference: MEPs Onset Latency (ms) Difference Baseline Vs Closing Diabetic Group Mean St Dev Normality Test P- Value Statistical Test P-Value of Statistical Test % Change In Amplitude baseline Vs Closing Significance P ? = Ho R-APB Baseline 23.84 7.049 0.005 Wilcoxon Signed Rank M= 7.00 P – Value 0.002 3.02% P ; ? = H1 R-APB Closing 24.56 7.061 0.005 L-APB Baseline 23.45 7.001 0.005 Wilcoxon Signed Rank M= 6.750 P – Value 0.002 2.86% P ; ? = H1 L-APB Closing 24.12 7.050 0.005 R-TA Baseline 30.99 6.183 0.277 Wilcoxon Signed Rank M= 7.00 P – Value 0.002 2.69% P ; ? = H1 R-TA Closing 31.82 6.630 0.024 L-TA Baseline 29.04 4.667 0.020 Wilcoxon Signed Rank M= 7.00 P – Value 0.004 2.31% P ; ? = H1 L-TA Closing 29.71 4.618 0.019 R-AH Baseline 32.56 6.270 0.427 Paired T-test T= -13.78 P – Value 0.000 2.05% P ; ? = H1 R-AH Closing 33.23 6.321 0.336 L-AH Baseline 33.95 5.098 0.013 Wilcoxon Signed Rank M= 7.250 P – Value 0.002 8.95% P ; ? = H1 L-AH Closing 36.99 6.561 0.126 R-QUAD Baseline 24.30 7.788 0.005 Wilcoxon Signed Rank M= 7.00 P – Value 0.002 2.88% P ; ? = H1 R-QUAD Closing 25.00 7.736 0.005 L-QUAD Baseline 24.57 8.162 0.005 Wilcoxon Signed Rank M= 6.750 P – Value 0.002 2.65% P ; ? = H1 L-QUAD Closing 25.22 8.109 0.00575 M00646922 MIDDLESEX UNIVERSITY 11. Question 7: Can Diabetes Mellitus lead to increase in onset latency and decrease in amplitude during intraoperative monitoring of scoliosis correction surgery? P-value was used to define the results when P ? (0.05) we believed on null hypothesis (Ho) which was there is no difference. Null hypothesis (Ho) = Diabetes Mellitus cannot lead to decrease in amplitude (µV) during intraoperative monitoring of scoliosis correction surgery. Alternative hypothesis (H?) = Diabetes Mellitus can lead to decrease in amplitude (µV) during intraoperative monitoring of scoliosis correction surgery. Null hypothesis (Ho) = Diabetes Mellitus cannot lead to increase in onset latency (ms) during intraoperative monitoring of scoliosis correction surgery. Alternative hypothesis (H?) = Diabetes Mellitus can lead to increase in onset latency (ms) during intraoperative monitoring of scoliosis correction surgery. Amplitude and onset latency of both right and left median and posterior tibial nerves was compared between non-diabetic and diabetic groups to find out the difference. Likewise, amplitude and onset latency of both right and left abductor pollicis brevis (APB), tibialis anterior (TA), abductor hallucis (AH) and quadriceps (QUAD) were compared between non-diabetic and diabetic groups. The table below is illustrating that Mann-Whitney test was applied for the amplitude of MEPs and onset latency of both SSEPs and MEPs because we analyzed difference for the data which was not time series, had means, independent samples and two groups but either data had non-normal distribution or insignificant Levene’s variance test. Two sample tests were applied for the amplitude of SSEPs because we analyzed difference for the data with means, two groups, independent samples, equal variance and normal distribution. We rejected the null hypothesis for both amplitude (µV) and onset latency (ms). We accepted the alternative hypothesis (H?) as stated erstwhile. So, diabetes mellitus could increase the onset latency (ms) as well as could decrease the amplitude (µV) for both upper and lower limbs during intraoperative monitoring (SSEPs & MEPs) of scoliosis correction surgery because of P < ? (0.05).76 M00646922 MIDDLESEX UNIVERSITY Table 14: Comparison of SSEPs and MEPs among the Non-Diabetic and Diabetic group: Comparison of SSEPs and MEPs among a Non-Diabetic and Diabetic group Mean St Dev Normality Test P- Value Equal variance Levene’s Test Statistical Test P-Value of Statistical Test Significance P ? = Ho Non-Diabetic SSEPs Amplitude (µ?) 2.569 2.038 0.215 Vs P-Value 0.064 Two Sample T-Test T= 19.89 P – Value 0.000 P ; ? = H1 Diabetic SSEPs Amplitude (µ?) -13.85 1.138 0.589 Non-Diabetic MEPs Amplitude (µ?) 0.635 0.3205 0.789 P-Value 0.174 Mann Whitney Test W=100 P – Value 0.0009 P ; ? = H1 Diabetic MEPs Amplitude (µ?) -4.385 3.884 0.005 Non-Diabetic SSEPs Onset Latency (ms) 0.5625 0.5813 0.146 P-Value 0.000 Mann Whitney Test W= 36 P – Value 0.0009 P ; ? = H1 Diabetic SSEPs Onset Latency (ms) 5.579 3.417 0.063 Non-Diabetic MEPs Onset Latency (ms) 1.813 3.170 0.005 P-Value 0.713 Mann Whitney Test W=47 P – Value 0.0313 P ; ? = H1 Diabetic MEPs Onset Latency (ms) 3.462 2.255 0.00577 M00646922 MIDDLESEX UNIVERSITY 12. Percentage change in SSEPS amplitude: The graph below is depicting the percentage change in somatosensory evoked potentials (SSEPs) amplitude monitored from the right and left median (RMN ; LMN) and posterior tibial nerves (RTN ; LTN) throughout the scoliosis correction surgery among the diabetic and non-diabetic group. Blue bars are demonstrating percentage increase in amplitude from the baseline among non-diabetic patients. Orange bars are signifying percentage decrease in amplitude from the baseline among diabetic patients. Negative (-) sign is indicating a reduction in amplitude among diabetic patients. Figure 23: Bar chart for the percentage change is SSEPs amplitude among both groups. 4.10%4.46%0.70%1.03%-12.45%-13.95%-14.92%-14.09%-20.00%-15.00%-10.00%-5.00%0.00%5.00%10.00%RMNLMNRTNLTN% Change in SSEPS amplitude among diabetic and non-diabetics during the scoliosis surgery N-DMDM78 M00646922 MIDDLESEX UNIVERSITY 13. Percentage change in SSEPs onset latency: The graph below is portraying the percentage change in somatosensory evoked potentials (SSEPs) onset latency monitored from the right and left median (RMN ; LMN) and posterior tibial nerves (RTN ; LTN) throughout the scoliosis correction surgery among the diabetic and non-diabetic group. Blue bars are indicating percentage increase in onset latency from the baseline among non-diabetic patients. Orange bars are signifying percentage increase in onset latency from the baseline among diabetic patients. Figure 24: Bar chart for the percentage change in SSEPs onset latency among groups. 0.74%1.35%0.12%0.08%7.52%9.79%2.72%2.30%0.00%2.00%4.00%6.00%8.00%10.00%12.00%RMNLMNRTNLTN% Change in SSEPs onset latency among diabetics and non-diabetics during the scoliosis surgeryN-DMDM79 M00646922 MIDDLESEX UNIVERSITY 14. Percentage Change in MEPs amplitude: The graph below is illustrating the percentage change in motor evoked potentials (MEPs) amplitude monitored from right and left abductor pollicis brevis (R-APB ; L-APB), tibialis anterior (R-TA ; L-TA), abductor hallucis (R-AH ; L-AH) and quadriceps (R-QUAD ; L-QUAD) throughout the scoliosis correction surgery among diabetic and non-diabetic group. Blue bars are indicative of the percentage increase and decrease in amplitude from the baseline among non-diabetic patients. Orange bars are signifying percentage decrease in amplitude from the baseline among diabetic patients. Negative (-) sign is indicating a decline in amplitude. Figure 25: Bar chart for the percentage change in MEPs amplitude among groups. 0.77%1.03%0.55%0.44%-0.10%-0.82%0.98%0.39%-5.47%-2.32%-4.46%-2.58%-13.49%-1.78%-2.35%-2.63%-16.00%-14.00%-12.00%-10.00%-8.00%-6.00%-4.00%-2.00%0.00%2.00%R-APBL-APBR-TAL-TAR-AHL-AHR-QUADL-QUAD% Change in MEPs amplitude among diabetics and non-diabetics during scoliosis surgeryNon-Diabetic GroupDiabetic Group80 M00646922 MIDDLESEX UNIVERSITY 15. Percentage change is MEPs onset latency: The graph below is illustrating the percentage change in motor evoked potentials (MEPs) onset latency monitored from right and left abductor pollicis brevis (R-APB ; L-APB), tibialis anterior (R-TA ; L-TA), abductor hallucis (R-AH ; L-AH) and quadriceps (R-QUAD ; L-QUAD) throughout the scoliosis correction surgery among diabetic and non-diabetic group. Blue bars are indicative of the percentage increase in onset latency from the baseline among non-diabetic patients. Orange bars are signifying percentage increase in onset latency from the baseline among diabetic patients. Figure 26: Bar chart for the percentage change in MEPs onset latency among groups. 0.39%0.43%0.21%0.43%0.22%9.40%2.66%0.76%3.02%2.86%2.69%2.31%2.05%8.95%2.88%2.65%0.00%1.00%2.00%3.00%4.00%5.00%6.00%7.00%8.00%9.00%10.00%R-APBL-APBR-TAL-TAR-AHL-AHR-QUADL-QUAD% Change in MEPs onset latency among diabetics and non-diabetics during scoliosis surgeryNon-Diabetic GroupDiabetic Group81 M00646922 MIDDLESEX UNIVERSITY SECTION-IV82 M00646922 MIDDLESEX UNIVERSITY DISCUSSION: Many authors already reported the adverse effect of the diabetes mellitus on the sensory and motor peripheral nerves. In this study, statistical results proved that diabetes mellitus could increase the onset latency and decrease the amplitude of somatosensory and motor evoked potentials (SSEPs ; MEPs) significantly among diabetic patients during scoliosis surgery as compared to the non-diabetic patients during scoliosis surgery. It was found that somatosensory and motor evoked potentials are always susceptible to minor changes during scoliosis surgery irrespective of diabetes mellitus, but these changes are not significant clinically as well as statistically. Baseline somatosensory and compound motor nerve action potentials (SNAP ; CMAP) recorded before the commencement of the scoliosis surgery were compared with closing somatosensory, and motor evoked potentials recorded after the closure of the skin for both diabetic and non-diabetic groups. Statistical analysis was done by using Wilcoxon Signed Rank and Paired T-test. P-value of the statistical test and % change in amplitude ; onset latency between baseline and closing somatosensory evoked potentials were used to define the results. It was found that right median nerve somatosensory evoked potentials (RMN-SSEPs) amplitude was decreased by 12.45% among diabetic patients and it was increased by 4.10% among non-diabetic patients at the level of closure. Onset latency (OL) of the right median nerve somatosensory evoked potentials (RMN-SSEPs) was increased by 7.52% among diabetic patients and 0.74% among non-diabetic patients. Similarly, left median nerve somatosensory evoked potentials (LMN-SSEPs) amplitude was decreased by 13.95% among the diabetic group, and it was increased by 4.46% among the non-diabetic group. Although, left median nerve somatosensory evoked potentials (LMN-SSEPs) onset latency (OL) was increased 9.79% among diabetic patients and 1.35% among non-diabetic patients. Likewise, right posterior tibial nerve somatosensory evoked potentials (RTN-SSEPs) amplitude was decreased by 14.92% among diabetic individuals, and it was increased by 0.70% among non-diabetic individuals. Though, right posterior tibial nerve somatosensory evoked potentials (RTN-SSEPs) onset latency (OL) was increased 2.72% among diabetic patients and 0.12% among non-diabetic patients. Correspondingly, left posterior tibial nerve somatosensory evoked potentials (LTN-SSEPs) amplitude was decreased by 14.09% among the diabetic83 M00646922 MIDDLESEX UNIVERSITY group, and it was increased by 1.03% among the non-diabetic group. However, left posterior tibial nerve somatosensory evoked potentials (LTN-SSEPs) onset latency (OL) was increased 2.30% among diabetic patients and 0.08% among non-diabetic patients. Motor evoked potentials (MEPs) analysis revealed that amplitude of the right abductor pollicis brevis (R-APB) was decreased by 5.47% among diabetic patients and it was increased by 0.77% among non-diabetic patients. Onset latency (OL) of the right abductor pollicis brevis (R-APB) was increased by 3.02% among diabetic patients and 0.39% among non-diabetic patients. Similarly, left abductor pollicis (L-APB) motor evoked potentials amplitude was decreased 2.32% among diabetics, and it was increased by 1.03% among non-diabetics. Though, onset latency (OL) of left abductor pollicis brevis (L-APB) was increased by 2.86% among diabetic groups and 0.43% among non-diabetic groups. In the same way, the right tibialis anterior (R-TA) motor evoked potentials amplitude was decreased 4.46% among the diabetic group, and it was increased by 0.55% among the non-diabetic group. Although, onset latency (OL) of the right tibialis anterior (R-TA) was increased by 2.69% among diabetic individuals and 0.21% among non-diabetic individuals. Correspondingly, the left tibialis anterior (L-TA) motor evoked potentials amplitude was decreased by 2.58% among diabetic patients, and it was increased by 0.44% among non-diabetic patients. And onset latency of the left tibialis anterior (L-TA) was increased by 2.31% and 0.43% among diabetic and non-diabetic patients respectively. In the same manner, the right abductor hallucis (R-AH) motor evoked potential amplitude was decreased to 13.49% among the diabetic group, and it was reduced by 0.10% among the non-diabetic group. Onset latency (OL) of the right abductor hallucis was increased 2.05% among diabetic patients and 0.22% among non-diabetic patients. Likewise, left abductor hallucis (L-AH) motor evoked potentials amplitude was decreased by 1.78% among diabetic individuals, and it was reduced by 0.82% among non-diabetic individuals. Onset latency (OL) of the left abductor hallucis (L-AH) was a quiet variable than the other muscle groups. It was increased by 8.95% among people with diabetes and 9.40% among non-diabetics. Motor evoked potentials amplitude of the right quadriceps (R-QUAD) was decreased to 2.35% among diabetic patients, and it was increased by 0.98% among non-diabetic patients. And onset latency (OL) of right quadriceps (R-QUAD) was increased by 2.88% among people with diabetes and 2.66% among non-diabetics. Correspondingly, the left quadricep (L-QUAD)84 M00646922 MIDDLESEX UNIVERSITY motor evoked potentials amplitude was decreased 2.63% among a diabetic group of patients, and it was increased by 0.39% among a non-diabetic group of the patients. Onset latency (OL) of the left quadriceps (L-QUAD) rose 2.65% among a diabetic group of patients and 0.76% among non-diabetic groups of the patients. Generally, the amplitude of the both somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) were decreased among a diabetic group of the patients as compared to the non-diabetic group of the patients. The amplitude of the sensory and motor action potentials (SNAP ; CMAP) reflects the number of the active conducting nerve and muscle fibres. Amongst diabetic patient’s extra body glucose is get deposited into the nerves and muscles. This glucose damage the active nerve and muscle fibres which can ultimately cause peripheral neuropathy and muscle weakness. It can be the reason for the reduction in amplitude among diabetic patients during scoliosis surgery. Likewise, onset latency (OL) of somatosensory and motor evoked potentials (SSEPs and MEPs) was increased among both diabetic and non-diabetic groups. But, this increase in onset latency was significantly high among diabetics than non-diabetic patients. Onset latency (OL) represents the speed of conduction of the sensory and motor nerves. Increase in onset latency represents slow conduction of the sensory and motor nerves. The probable reason behind the similar behaviour of both groups may be because of anaesthesia or scoliosis surgery itself. Anaesthesia can increase the onset latency by slowing down transmission of the nerve impulse, and scoliosis surgery can also cause mild to moderate compression on peripheral nerves leading to increasing onset latency. In the diabetic patients’ elevated levels of the glucose damage the myelin sheath of the nerves by depositing extra glucose inside the nerves and muscles ultimately slowing the nerve impulse transmission and conduction velocity. Secondly, diabetes affects the blood vessels which can reduce blood supply to the nerve and muscles leading to slow transmission of the nerve impulse. Possibly, this can be the reason behind the significant increase in onset latency among diabetic patients as compared to non-diabetic patients. The results we discussed earlier were only for either diabetics or non-diabetics. After that, we linked the differences of somatosensory and motor evoked potentials (SSEPs ; MEPs) by comparing amplitude and onset latency of the diabetic group with the amplitude and onset latency of the non-diabetic group. Mann Whitney and Two-Sample T-test was used for this analysis, and it was found P-value of the somatosensory and motor evoked potentials amplitude85 M00646922 MIDDLESEX UNIVERSITY and onset latency was lower than the value of alpha (? = 0.05). It means there is that diabetes mellitus can lead to increase in onset latency and decrease in amplitude during intraoperative monitoring of scoliosis correction surgery. These results were very consistent with the work of Arrthy S, and colleagues. They compared median nerve somatosensory evoked potentials (MN-SSEPs) between diabetic and non-diabetic patients. They measured the onset latency (OL) and central conduction time (CCT) of both groups and applied an unpaired T-test on the mean values. P-value of the statistical test was less than alpha (? = 0.05) for diabetic patients. They concluded that the diabetic group had prolonged central conduction time due to delayed central and peripheral nerve conduction as compared to the non-diabetic group (Arrthy et al., 2014). Frequently, during spinal cord correction surgeries, e.g. scoliosis, alarming criteria for somatosensory and motor evoked potentials is decreased in the amplitude of more than 50% and an increase in onset latency or peak latency of more than 10%. For motor evoked potentials all or none criteria is also used. Patients meeting these criteria during correction surgeries usually presents with a neurological deficit after surgery if undetected or untreated on the spot. Many scientists were mostly comfortable with somatosensory evoked potentials (SSEPs). We monitored both somatosensory and motor evoked potentials (SSEPs and MEPs) in this study because together their sensitivity and specificity was 100% and 98% respectively (Marafona and Machado, 2018). We found that diabetes caused a significant reduction in amplitude and a substantial increase in onset latency among diabetic groups as compared to the non-diabetic group, but these findings were quite below than the alarming criteria. Every single patient from both groups was examined after the surgery for any neurological deficit, but no patient was reported with any neurological shortfall. Hyun Mi oh and colleagues also found a comparable conclusion to this study. They related median nerve somatosensory evoked potentials (MN-SSEPs) bilaterally among diabetic and non-diabetic patients. They measured cortical and inter-peak latencies of both groups and analysed data statistically. They found that the P-value of the statistical test was less than alpha (? = 0.05) for diabetic patients. So, they summarised that N20 cortical latency and N20-P25 peak latencies were significantly increased among diabetic patients as compared to the non-diabetics. The central conduction time was also meaningfully increased among diabetic patients (Oh et al., 2015). Another author Dr Manoj Kumar and his colleagues86 M00646922 MIDDLESEX UNIVERSITY evaluated the effect of diabetes on the evoked potentials. He compared the brainstem auditory evoked potentials (BAEPs) among diabetic and non-diabetic patients. He measured the wave onset and interpeak latency and analysed the mean values statistically. He found that interpeak and onset latencies of the brainstem auditory evoked potentials were significantly increased among diabetic patients than non-diabetic patients (Jain et al., 2018). Effect of diabetes on the peripheral nerves was evaluated by Hikmet Dolu and colleagues. Their results were also like this study. They monitored multimodal evoked potentials bilaterally from two groups of patients named as diabetic and non-diabetic. Somatosensory evoked potentials (SSEPs) were recorded from the median and posterior tibial nerve along with brainstem evoked potentials (BAEPs) and visual evoked potentials (VEPs). They also monitored the motor evoked potentials (MEPs). They compared Peripheral, cortical, interpeak latencies and central motor conduction time between diabetic and non-diabetic groups. They found that visual evoked potentials latencies and peripheral and central latencies for median nerve and posterior tibial nerves were prolonged among the diabetic group. Brainstem auditory evoked potentials were remained normal in diabetics. Central conduction time and latency of the motor evoked potentials were also increased. So, they concluded that duration and severity of diabetes cause peripheral and central neuropathies (Dolu et al., 2003). Results of this study were also very consistent with an earlier study by Giuseppe Pozzessere, MD who evaluated the different modalities among diabetic and non-diabetic patients. He monitored multimodal evoked potentials, somatosensory evoked potentials (SSEPs) from the median and posterior tibial nerves, brainstem auditory evoked potentials (BAEPs) and visual evoked potentials (VEPs). He measured the latencies from all different modalities and analysed mean values statistically. He found a significant reduction in conduction velocity and a momentous increase in the latencies among most of the modalities (Pozzessere et al., 1988). Jin Jun Luo and colleagues also did a comparative study with multiple modalities. They measured onset latencies from somatosensory evoked potentials (SSEPs), visual evoked potentials (VEPs) and brainstem evoked potentials. They analysed the data by comparing the mean values and found a significant reduction in central conduction velocity of the somatosensory evoked potentials but no noteworthy change in conduction velocity of the visual and brainstem auditory evoked potentials (Luo et al., 2015).87 M00646922 MIDDLESEX UNIVERSITY Effects of diabetes mellitus on the somatosensory and motor evoked potentials (SSEPs ; MEPs) during spinal cord surgery together were infrequently studied. Most of the authors were more focused on somatosensory evoked potentials (SSEPs), and they were very constrained by the onset or interpeak latencies as pronounced earlier. None of them either examined latencies and amplitude difference of the motor evoked potentials (MEPs) neither amplitude difference of somatosensory evoked potentials (SSEPs). Pavol Kucera and colleagues went one step further and studied the effect of the diabetes mellitus on the spinal cord lesions by investigating somatosensory and motor evoked potentials to prevent the side effects of diabetes in patients with spinal cord injuries. They divided the patients into two groups named as diabetic and control group. They stimulated the median and ulnar nerve from upper limb and fibular nerve from lower limb for somatosensory evoked potentials (SSEPs) and measured latencies from each nerve. Similarly, they also stimulated the first dorsal interosseous muscle and extensor digitorum brevis for motor evoked potentials (MEPs) latencies. They analyzed the data and found that diabetes caused prolonged peripheral and central conduction time. They confirmed that somatosensory and motor evoked potentials could be used for endorsement of imperceptible lesion of the spinal cord among diabetic patients. Results of our study were also very parallel with the findings of Pavol Kucera and colleagues because we also measure onset latencies from both somatosensory and motor evoked potentials. We also related the results between the diabetic group and non-diabetic group. We found that diabetes increased onset latency significantly among diabetic group than the non-diabetic group and caused prolonged peripheral and conduction time (Kucera et al., 2005). Piotr Rajewski and colleagues concluded the very similar results to this study. They only included diabetic patients and then divided sample size according to gender, type of diabetes, glycemic control and peripheral polyneuropathy. They monitored somatosensory evoked potentials (SSEPs) and visual evoked potentials (VEPs). Median and posterior tibial nerves were used for somatosensory evoked potentials. They noted onset and peak latencies and worked out central conduction time for each modality. They found that 25% of patients with prolonged somatosensory latencies and central conduction times without signs of polyneuropathy. They also observed that 64.4% of patients with abnormal somatosensory latencies and central conduction times and 31.1% with visual evoked potentials abnormalities.88 M00646922 MIDDLESEX UNIVERSITY So, They concluded that evoked potentials examination could detect subclinical changes among diabetic patients (Rajewski et al., 2007). A scientist Ping-Hui Wang and colleagues studied the effect of diabetes on the decompression spinal cord surgeries by recording somatosensory and motor evoked potentials (SSEPs and MEPs) in the rats. Their findings of SSEPs and MEPs on rats’ model were also alike in this study. They compared Streptozotocin-induced diabetic rats with sciatic nerve compression with the non-diabetic rats with sciatic nerve compression. They measured the amplitude and onset latency of somatosensory and motor evoked potentials (SSEPs and MEPs) and analysed the data with the Kruskal-Wallis test. They noticed that compression of the sciatic nerve caused significant reduction of amplitude and increase in onset latency of both somatosensory and motor evoked potentials and these findings were more significant among diabetic rats’ group. Decompression surgery was performed, and they monitored the SSEPs and MEPs and found that both SSEPs and MEPs were significantly improved among both groups. They measured SSEPs and MEPs again after eight weeks and founded that non-diabetic rats’ functions were normal but diabetic groups SSEPs and MEPs were not recovered. So, they summarised that decompression surgery is effective among diabetics, but complete recovery is not possible (Wang et al., 2017). Critical evaluation of the results of this study with all previous studies reflected that the results of this study were very reliable and even more detailed because patients were strictly examined for selection criteria and allocated into diabetic and non-diabetic groups. Amplitude and onset latencies were measured from both somatosensory and motor evoked potentials (SSEPs and MEPs) data before commencement of the surgery as a baseline and after the closure of the skin as a closing potential. Data were analyzed statistically as well as clinically, and results were given in the form of tables and graph which can be easily understood. Now, as we found that diabetes does affect amplitude and onset latency, but these variations are not clinically noteworthy. So, these results will be helpful to prevent false alarms during spinal cord surgical procedure among diabetic patients, to facilitate the surgical procedure precisely, and to plan the postoperative management according to the neuromuscular status of the nerve and muscles.89 M00646922 MIDDLESEX UNIVERSITY Limitations: Even though almost every possible effort was made to justify the criteria for this study, but there are still some methodical concerns. The first limitation of this study was sample size was too small. It was difficult to find the patients with both variables (diabetes and scoliosis) together because both conditions are not common together. The second limitation of this study was that data was taken from a single hospital setting due to the shortage of the time. This study should be completed within the three-month period. Another possible constraint for the study is that we only appraised the effect of diabetes on only one type of spinal cord surgery (Scoliosis), which can reduce the specificity and sensitivity of this study. The last limitation of this study was the design of the study. This study was a retrospective cohort study in which data was taken from previous surgeries. The drawback of this type of study was we had less control over variables, and to some extent, this design is susceptible to information or recall bias. Recommendation: Further studies are required to find out the effect of diabetes on somatosensory and motor evoked potentials (SSEPs and MEPs) during scoliosis correction surgery. This study can be amended by varying the study design from a retrospective cohort study to either prospective cohort study or randomized control trial. This will increase the level of the evidence for this study. A sample size of the study can be improved by repeating this study at a bigger level with a greater number of the patients in both diabetic and non-diabetic group so more accurate results can be found. Data can be collected from more than one hospital settings or even from more than one country at the international level which will increase the sample size as well as the level of evidence. Effect of diabetes on spinal cord operations can be measured more precisely by including numerous surgical procedures in the study e.g. spinal cord tumours, ankylosing spondylitis and other degenerative spinal cord problems and recording both somatosensory and motor evoked potentials from upper and lower limbs.90 M00646922 MIDDLESEX UNIVERSITY CONCLUSION: Diabetic neuropathy is one of the foremost complications of the diabetes mellitus. It’s a major microvascular problem which affects diabetic patients and causes hitches in central, peripheral and autonomic nervous systems. Patients with scoliosis deformity and diabetes are more prone to get these problems. Many studies attempted to find out the effect of diabetes on the patients with spinal cord lesions. This study was also carried out to comprehend the consequence of diabetes mellitus on the peripheral nerves and spinal cord in scoliosis surgery during intraoperative monitoring so postoperative management can be planned accordingly. Baseline somatosensory and motor evoked potentials (SSEPs ; MEPs) amplitude of the non-diabetic group was compared with the closing amplitude of the same group, and it was found that amplitude was slightly increased (0.39% to 4.46%) at the end of the surgery. On the other side, when baseline amplitude of the both somatosensory and motor evoked potentials (SSEPs ; MEPs) of diabetic patients were compared with the closing amplitude of the same group, it was found that amplitude was significantly decreased (-1.78% to -14.92%) at the end of the surgery. As it was reflected by the preceding studies that diabetes cause irreversible damage to the conduction fibres and motor units. Our results evidenced this declaration as we found a consistent decrease in amplitude. Likewise, baseline onset latency (OL) of somatosensory and motor evoked potentials (SSEPs ; MEPs) was compared with closing onset latency (OL) for both non-diabetic and diabetic groups, and it was noted that onset latency was increased among both diabetic and non-diabetic groups. But, this increase in onset latency was significantly high among diabetics than non-diabetic patients. These results were very consistent and identical to the findings of the earlier studies. The aim of the study was approached by equating the differences in amplitude and onset latencies between diabetic and non-diabetic groups. It was found that the P-value of the somatosensory and motor evoked potentials (SSEPs ; MEPs) amplitude and onset latency were lower than the value of alpha (? = 0.05). So, we concluded that diabetes does affect amplitude and onset latency, but these variations are not clinically noteworthy. These results will be helpful clinically to prevent false alarms during spinal cord surgical procedure among diabetic patients, to facilitate the surgical procedure precisely, and to plan the postoperative management according to the neuromuscular status of the nerve and muscles.91 M00646922 MIDDLESEX UNIVERSITY SECTION-V92 M00646922 MIDDLESEX UNIVERSITY REFERENCES: 1. 2018. Scoliosis Correction Surgery. 2. ALLEN, M. D., CHOI, I. H., KIMPINSKI, K., DOHERTY, T. J. ; RICE, C. L. 2013. Motor unit loss and weakness in association with diabetic neuropathy in humans. Muscle ; nerve, 48, 298-300. 3. AMERMAN, E. C. 2018. HUMAN ANATOMY ; PHYSIOLOGY PLUS PEARSON MASTERING ANATOMY ; PHYSIOLOGY WITH PEARSON ETEXT, GLOBAL… EDITION, PEARSON EDUCATION LIMITED. 4. AMIRI, M., HOSSEINI, S. M. ; MAGHSOUDI, R. 2016. Diabetes mellitus type 1; is it a global challenge. 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Journal of pain research, 10, 643.96 M00646922 MIDDLESEX UNIVERSITY SECTION-VI97 M00646922 MIDDLESEX UNIVERSITY APPENDIX-I: MIDDLESEX UNIVERSITY ETHICAL FORM:98 M00646922 MIDDLESEX UNIVERSITY APPENDIX-II: GHURKI TRUST TEACHING HOSPITAL ETHICAL REVIEW COMMITTEE (ERC) CERTIFICATE:99 M00646922 MIDDLESEX UNIVERSITY APPENDIX-III: SSEPs and MEPs raw data: Table 15: Median Nerve SSEPs raw data: Non-Diabetic: Median Nerve SSEPs N20/P25 ms Diabetic: Median Nerve SSEPs N20/P25 ms Baseline Closing Baseline Closing RMN RMN LMN LMN RMN RMN LMN LMN RMN RMN LMN LMN RMN RMN LMN LMN C3-Fpz C3-C4 C4-Fpz C4-C3 C3-Fpz C3-C4 C4-Fpz C4-C3 Cz-Fpz C4-C3 Cz-Fpz C3-C4 Cz-Fpz C4-C3 Cz-Fpz C3-C4 Amp µ? 5.3 5.2 5.1 4.8 5.2 5.8 5.2 5.1 2.1 4.0 2.3 1.7 2.0 3.8 2.1 1.3 OL ms 12.5 12.7 11.6 11.8 12.4 12.5 11.7 11.9 12.8 12.6 13.5 12.5 13.4 12.8 13.7 12.6 Amp µ? 4.3 4.0 4.4 3.0 4.6 4.2 4.9 3.2 1.6 1.6 0.8 0.8 1.3 1.4 0.7 0.8 OL ms 14.1 13.3 13.4 10.2 14.2 13.2 13.1 10.6 12.3 11.6 11.0 10.7 12.6 11.9 11.4 11.3 Amp µ? 3.9 3.5 3.3 1.7 4.8 3.7 3.8 2.1 2.8 3.0 2.3 2.9 2.7 2.8 2.0 2.8 OL ms 14.4 14.7 12.8 11.4 14.5 14.5 13.0 12.1 15.4 14.1 13.5 13.8 15.7 16.3 15.6 16.2 Amp µ? 3.9 3.6 3.8 3.3 4.0 3.9 3.8 3.9 2.3 2.1 2.0 2.4 1.4 1.2 1.3 1.8 OL ms 14.5 13.9 13.8 14.0 14.7 14.2 14.1 14.4 14.0 14.2 13.8 13.8 15.5 15.7 15.1 15.0 Amp µ? 3.5 3.1 3.2 3.1 3.6 3.2 3.1 3.3 3.5 3.1 5.5 4.7 3.2 2.8 4.1 4.2 OL ms 13.2 13.3 13.3 12.9 13.3 13.5 13.4 13.2 15.5 14.3 14.8 14.0 16.8 15.5 16.3 15.9 Amp µ? 4.0 3.2 3.8 3.1 4.2 3.5 3.9 3.3 3.2 3.5 4.1 4.4 3.0 3.2 3.7 3.9 OL ms 16.5 16.8 14.3 14.6 16.3 16.7 14.5 14.3 13.5 13.3 13.6 13.8 14.4 14.2 14.3 14.7 Amp µ? 4.6 4.4 4.7 4.9 4.5 4.4 4.8 4.8 1.7 1.3 1.9 1.8 1.2 0.9 1.4 1.3 OL ms 16.7 16.6 14.8 15.3 16.7 16.5 15.0 15.2 18.5 18.8 18.7 19.2 21.7 22.0 22.6 23.4 Amp µ? 4.3 3.8 3.9 4.1 4.3 3.9 4.4 4.2 2.4 2.6 2.9 3.2 2.0 2.1 2.3 2.8 OL ms 14.0 14.6 14.5 14.8 14.1 14.5 14.5 14.8 16.2 15.7 16.1 16.3 17.1 16.9 17.8 17.6 Amp µ? 4.8 4.6 4.0 4.2 5.0 4.9 4.0 4.3 4.2 3.2 2.9 2.5 3.6 2.8 2.5 2.0 OL ms 17.9 17.4 16.9 18.0 18.1 17.4 17.0 17.8 15.6 15.3 16.0 15.6 16.3 16.1 16.9 16.3 Amp µ? 4.5 4.7 4.6 4.8 4.6 4.7 4.5 5.0 3.0 3.6 3.5 3.4 2.4 2.9 3.0 2.8 OL ms 16.8 15.9 16.5 16.9 17.1 16.0 16.7 17.3 18.7 17.8 17.6 18.6 21.3 19.4 20.4 22.1 Amp µ? 4.6 4.4 4.6 4.5 4.5 4.4 4.7 4.8 2.9 2.8 3.6 3.1 2.8 2.6 3.4 2.8 OL ms 18.7 17.3 18.2 18.0 19.5 18.2 19.0 18.7 13.7 12.8 15.0 15.1 14.4 13.9 15.7 16.0 Amp µ? 6.5 5.4 6.6 6.0 6.5 5.7 6.7 6.3 1.9 2.3 2.8 2.9 2.1 2.3 2.9 2.9 OL ms 20.8 18.8 16.4 15.6 21.1 19.1 16.7 16.0 17.1 18.0 17.9 17.4 17.5 18.8 18.6 18.9 Amp µ? 3.9 3.3 3.7 3.3 4.1 3.6 3.7 3.4 4.0 2.8 2.4 2.3 3.7 2.4 2.1 2.0 OL ms 15.8 14.2 13.3 14.5 15.8 14.3 13.5 14.5 15.7 16.5 15.8 15.4 16.3 17.1 16.6 16.1100 M00646922 MIDDLESEX UNIVERSITY Table 16: Posterior Tibial Nerve SSEPs raw data: Non-Diabetic: Tibial Nerve SSEPs N8/P37 ms Diabetic: Tibial Nerve SSEPs N8/37 ms Baseline Closing Baseline Closing RTN RTN LTN LTN RTN RTN LTN LTN RTN RTN LTN LTN RTN RTN LTN LTN Cz-Fpz C4-C3 Cz-Fpz C3-C4 Cz-Fpz C4-C3 Cz-Fpz C3-C4 Cz-Fpz C4-C3 Cz-Fpz C3-C4 Cz-Fpz C4-C3 Cz-Fpz C3-C4 Amp µ? 3.8 4.5 3.9 3.8 4.0 4.6 4.1 3.9 3.8 3.4 5.2 3.1 3.3 3.0 4.9 2.8 OL ms 17.9 19.3 18.3 19.5 18.0 19.5 18.6 19.6 21.0 27.5 26.8 28.3 23.8 28.3 27.1 28.9 Amp µ? 4.5 4.7 4.2 4.0 4.6 4.7 4.3 4.2 1.6 1.4 3.3 0.8 1.3 1.4 2.7 0.8 OL ms 25.5 25.2 27.0 27.8 25.4 25.3 27.1 27.6 20.3 21.0 18.2 19.8 20.6 21.4 18.8 20.3 Amp µ? 4.0 3.4 3.6 2.8 4.1 3.4 3.8 2.7 2.9 3.1 3.1 2.5 2.7 2.8 2.6 2.4 OL ms 28.5 27.2 25.3 26.2 28.7 27.4 25.0 26.1 29.7 30.5 29.3 30.2 30.3 31.1 29.9 30.8 Amp µ? 4.1 3.9 3.8 3.3 4.0 3.9 3.8 3.6 2.5 2.3 2.1 2.4 1.7 1.6 1.3 1.8 OL ms 31.8 30.7 31.3 31.2 31.7 30.7 31.2 31.2 28.4 28.1 29.0 28.8 29.4 28.8 29.7 29.3 Amp µ? 3.7 3.3 3.5 3.2 3.6 3.2 3.3 3.4 3.2 3.5 5.6 4.9 3.0 3.1 4.9 4.2 OL ms 28.3 27.7 26.6 25.3 28.2 27.6 26.6 25.5 28.7 28.4 29.1 28.5 29.3 28.9 29.8 29.1 Amp µ? 4.4 3.8 4.0 3.9 4.3 3.5 3.9 3.8 3.5 3.7 4.2 4.4 3.0 3.3 3.7 3.9 OL ms 30.1 30.3 29.7 29.4 30.3 30.1 29.5 29.5 31.1 30.7 29.3 29.8 31.8 31.5 30.1 30.6 Amp µ? 4.7 4.8 4.9 5.1 4.6 4.8 5.0 5.0 1.9 1.5 2.1 2.0 1.3 1.1 1.7 1.4 OL ms 28.4 28.6 28.9 29.1 28.4 28.5 29.0 29.1 29.9 30.1 29.4 29.8 30.7 30.9 30.1 30.6 Amp µ? 4.0 3.5 3.7 3.9 4.1 3.5 3.7 3.9 2.1 2.6 2.6 3.0 1.8 2.3 2.2 2.8 OL ms 27.7 28.1 27.3 27.6 27.5 28.0 27.3 27.5 29.3 28.4 29.1 29.0 29.9 28.7 29.6 29.5 Amp µ? 4.8 4.6 4.0 4.2 5.0 4.7 4.0 4.3 3.8 3.6 3.1 2.9 3.0 2.9 2.7 2.3 OL ms 17.9 17.4 16.9 18.0 18.1 17.4 17.0 17.8 24.1 26.3 25.7 26.2 24.8 26.9 26.3 27.0 Amp µ? 4.6 4.4 4.6 4.3 4.6 4.5 4.6 4.2 3.1 3.5 3.6 3.7 2.4 2.9 3.0 2.8 OL ms 26.8 25.9 26.5 26.9 26.8 26.1 26.6 26.8 28.7 27.8 28.6 28.6 29.3 29.4 29.4 29.1 Amp µ? 4.9 4.8 4.7 4.6 4.8 4.7 4.6 4.5 3.9 3.8 3.6 3.7 3.1 2.9 2.8 3.1 OL ms 25.7 26.3 25.2 26.0 25.5 26.2 25.0 25.7 27.7 28.8 28.0 28.1 28.5 29.3 28.7 28.9 Amp µ? 6.5 5.4 6.6 6.0 6.5 5.7 6.7 6.3 1.9 2.3 2.8 2.9 2.1 2.3 2.9 2.9 OL ms 20.8 18.8 16.4 15.6 21.1 19.1 16.7 16.0 27.1 28.0 27.9 27.4 27.8 28.7 28.5 28.0 Amp µ? 3.9 3.3 3.7 3.3 4.1 3.6 3.7 3.4 4.0 2.8 2.4 2.3 3.7 2.4 2.1 2.0 OL ms 25.8 24.2 24.3 24.5 25.8 24.3 24.5 24.5 31.2 30.8 29.9 30.5 31.7 31.4 30.7 31.2101 M00646922 MIDDLESEX UNIVERSITY Table 17: MEPs amplitude (µ?) raw data: Non-Diabetic: MEPs Amplitude (µ?) Diabetic: MEPs Amplitude (µ?) Right Left Right Left APB TA AH QUAD APB TA AH QUAD APB TA AH QUAD APB TA AH QUAD Baseline 165.7 166.1 24.5 25.3 186.9 98.8 46.2 84.5 123.1 156.1 79.0 65.2 131.3 146.2 84.2 67.4 Closing 171.2 169.0 25.2 30.2 192.3 99.4 47.3 86.1 99.8 127.2 67.1 62.5 122.3 133.8 78.5 60.2 Baseline 135.1 78.1 74.8 37.9 174.4 76.0 180.1 63.1 203.1 225.5 237.1 139.8 209.3 219.5 221.0 189.5 Closing 136.2 79.3 72.1 38.2 178.2 77.2 182.1 62.6 194.1 218.1 231.1 134.0 201.4 212.4 218.3 179.5 Baseline 117.5 52.7 45.2 26.9 99.8 47.1 26.5 40.0 87.4 73.2 71.0 87.1 84.3 79.5 73.2 89.2 Closing 117.9 53.0 45.5 27.1 100.2 47.5 27.0 40.2 84.1 72.3 69.2 85.9 82.1 77.9 71.7 88.0 Baseline 136.4 59.7 64.1 67.7 135.1 51.3 63.4 65.3 158.3 146.9 159.3 150.8 147.0 175.5 175.9 146.9 Closing 136.1 59.9 64.2 67.9 135.0 51.3 63.5 65.4 152.2 144.5 156.0 148.8 145.8 172.5 173.7 144.4 Baseline 174.4 167.9 170.2 158.9 160.5 179.5 173.3 131.1 204.4 228.4 234.2 138.6 207.3 216.4 220.1 179.5 Closing 174.2 168.2 171.0 159.0 161.0 181.1 172.9 131.5 199.9 225.3 132.1 135.4 203.5 214.3 218.5 176.6 Baseline 138.3 142.2 122.0 140.3 112.1 139.2 134.2 132.1 112.1 123.4 114.3 117.4 119.3 125.4 119.3 121.2 Closing 138.4 142.4 122.4 140.4 112.4 139.4 134.4 132.4 110.2 121.3 111.1 113.4 115.2 123.4 113.4 119.4 Baseline 127.2 135.5 149.4 130.3 129.7 133.3 140.5 129.2 184.2 173.2 199.1 168.2 185.1 174.4 189.5 167.2 Closing 127.0 135.1 149.5 130.9 128.8 132.9 141.2 130.0 173.2 167.3 188.8 163.1 182.5 171.2 187.6 163.3 Baseline 147.7 145.5 174.6 92.2 182.8 138.0 163.8 131.1 116.2 134.2 139.4 123.3 118.4 136.2 140.2 117.2 Closing 148.2 145.7 175.0 93.2 183.1 138.7 164.2 131.8 117.3 135.1 140.4 124.0 119.2 137.1 141.0 118.3 Baseline 133.4 153.4 158.4 139.4 126.6 152.3 159.3 134.9 87.4 73.2 71.0 87.1 84.3 79.5 73.2 89.2 Closing 133.0 153.0 158.0 139.0 126.2 152.0 159.0 134.5 84.1 72.3 69.2 85.9 82.1 77.9 71.7 88.0 Baseline 165.7 166.1 24.5 25.3 186.9 98.8 46.2 84.5 204.4 228.4 234.2 138.6 207.3 216.4 220.1 179.5 Closing 171.2 169.0 25.2 30.2 192.3 99.4 47.3 86.1 199.9 225.3 132.1 135.4 203.5 214.3 218.5 176.6 Baseline 138.3 142.2 122.0 140.3 112.1 139.2 134.2 132.1 123.1 156.1 79.0 65.2 131.3 146.2 84.2 67.4 Closing 138.4 142.4 122.4 140.4 112.4 139.4 134.4 132.4 99.8 127.2 67.1 62.5 122.3 133.8 78.5 60.2 Baseline 138.3 142.2 122.0 140.3 112.1 139.2 134.2 132.1 184.2 173.2 199.1 168.2 185.1 174.4 189.5 167.2 Closing 138.4 142.4 122.4 140.4 112.4 139.4 134.4 132.4 173.2 167.3 188.8 163.1 182.5 171.2 187.6 163.3 Baseline 135.1 78.1 74.8 37.9 174.4 76.0 180.1 63.1 158.3 146.9 159.3 150.8 147.0 175.5 175.9 146.9 Closing 136.2 79.3 72.1 38.2 178.2 77.2 182.1 62.6 152.2 144.5 156.0 148.8 145.8 172.5 173.7 144.4102 M00646922 MIDDLESEX UNIVERSITY Table 18: MEPs onset latency (OL) raw data: Non-Diabetic: MEPs Latency (ms) Diabetic: MEPs Latency (ms) Right Left Right Left APB TA AH QUAD APB TA AH QUAD APB TA AH QUAD APB TA AH QUAD Baseline 20.8 38.8 36.2 26.2 19.3 25.8 35.2 19.8 23.2 34.1 35.4 22.1 24.1 33.6 33.4 23.2 Closing 21.0 38.7 36.0 30.2 19.2 26.0 35.0 20.0 24.1 34.9 36.2 22.8 24.9 34.2 33.9 23.8 Baseline 20.3 23.5 38.3 22.3 19.0 26.5 36.8 19.7 19.0 22.2 30.0 17.0 17.3 23.0 34.3 17.0 Closing 20.5 23.3 38.5 22.5 19.2 26.7 40.0 19.9 19.5 22.8 30.7 17.9 17.8 23.6 34.8 17.7 Baseline 25.8 28.3 42.7 21.0 27.2 30.8 44.3 17.0 39.3 36.3 34.2 40.7 38.4 32.3 34.1 41.7 Closing 25.7 28.4 42.9 21.1 27.3 31.0 44.4 17.3 40.0 37.0 35.1 41.3 39.1 33.0 34.9 42.2 Baseline 26.7 32.2 45.5 24.0 26.9 33.0 45.2 24.1 21.0 33.8 40.8 21.3 20.7 29.3 38.7 20.3 Closing 26.8 32.4 45.3 24.1 27.1 33.3 45.4 24.4 21.8 34.3 41.3 21.9 21.4 30.0 29.5 20.9 Baseline 22.2 30.3 39.3 21.8 25.2 32.7 43.2 31.2 22.5 24.7 31.1 19.2 19.9 24.4 33.1 18.8 Closing 22.3 30.4 39.5 21.9 25.1 32.8 43.1 31.1 23.1 25.3 31.7 19.7 20.4 25.0 33.8 19.3 Baseline 24.2 23.4 19.1 33.4 26.1 22.9 24.1 31.2 19.2 23.4 24.5 22.1 19.8 24.1 24.9 22.4 Closing 24.3 23.7 19.5 33.2 26.4 22.7 24.5 31.3 20.0 25.2 24.9 22.9 20.5 25.0 25.5 23.3 Baseline 16.8 23.8 35.5 23.5 18.3 24.3 36.0 18.2 20.8 42.3 40.3 28.2 20.3 34.9 44.0 28.2 Closing 16.7 23.7 35.4 23.4 18.2 24.2 35.5 18.1 21.3 42.9 41.1 28.9 20.8 35.4 44.7 28.9 Baseline 22.3 26.5 37.5 18.2 21.3 25.3 36.0 18.7 23.2 34.1 35.4 22.1 24.1 33.6 33.4 23.2 Closing 22.5 26.7 37.7 18.4 21.5 25.5 36.2 18.9 24.1 34.9 36.2 22.8 24.9 34.2 33.9 23.8 Baseline 20.8 38.8 36.2 26.2 19.3 25.8 35.2 19.8 23.2 34.1 35.4 22.1 24.1 33.6 33.4 23.2 Closing 21.0 38.7 36.0 30.2 19.2 26.0 35.0 20.0 24.1 34.9 36.2 22.8 24.9 34.2 33.9 23.8 Baseline 20.3 23.5 38.3 22.3 19.0 26.5 36.8 19.7 19.0 22.2 30.0 17.0 17.3 23.0 34.3 17.0 Closing 20.5 23.3 38.5 22.5 19.2 26.7 40.0 19.9 19.5 22.8 30.7 17.9 17.8 23.6 34.8 17.7 Baseline 25.8 28.3 42.7 21.0 27.2 30.8 44.3 17.0 39.3 36.3 34.2 40.7 38.4 32.3 34.1 41.7 Closing 25.7 28.4 42.9 21.1 27.3 31.0 44.4 17.3 40.0 37.0 35.1 41.3 39.1 33.0 34.9 42.2 Baseline 26.7 32.2 45.5 24.0 26.9 33.0 45.2 24.1 21.0 33.8 40.8 21.3 20.7 29.3 38.7 20.3 Closing 26.8 32.4 45.3 24.1 27.1 33.3 45.4 24.4 21.8 34.3 41.3 21.9 21.4 30.0 29.5 20.9 Baseline 24.2 23.4 19.1 33.4 26.1 22.9 24.1 31.2 19.2 23.4 24.5 22.1 19.8 24.1 24.9 22.4 Closing 24.3 23.7 19.5 33.2 26.4 22.7 24.5 31.3 20.0 25.2 24.9 22.9 20.5 25.0 25.5 23.3