Abstract Genetic factors have been implicated to play a role in both degenerative lumbar spinal stenosis (LSS) and intervertebral disc disease (IDD). Sequence variations in the genes coding for collagen IX and inflammatory mediators have been indicated as risk factors for IDD. Nine genes coding for intervertebral disc (IVD) collagens I, II, IX and XI and aggrecan (AGC1) were analyzed for sequence variations in 29 Finnish individuals with LSS. In addition, two polymorphisms in the vitamin D receptor gene and one in the matrix metalloproteinase-3 gene were studied. Study subjects were analyzed both clinically and radiologically. Results indicated an association between the COL11A2 IVS6-4 a to t polymorphism and LSS (p = 0.0016). Moreover, the t/t genotype was found more often in the patient group compared to controls (p = 0.0011). A novel splicing mutation, likely resulting in the synthesis of a truncated protein, was identified in COL9A2. Eight hundred four Chinese individuals were screened for the presence of the Trp2 and Trp3 alleles. The Trp2 allele was found in 20% of the individuals compared to the previously reported 5% in Finnish patients with IDD characterized by sciatica. The Trp2 allele was found to predispose to IVD degeneration and end plate herniations, increasing the risk by 2.4-fold from 40 to 49 years of age. In addition, the degeneration was worse in individuals with the Trp2 allele. The risk for annular tears was 4-fold greater in study subjects from 30 to 39 years of age who were Trp2 positive. Surprisingly, the Trp3 allele was absent even though it was found in about 9% of Finnish individuals. One hundred fifty-five Finnish individuals with IDD characterized by sciatica were analyzed for sequence variations in four genes coding for inflammatory mediators IL1A, IL1B, IL6, and TNFA. In addition, sixteen polymorphisms in inflammatory mediator genes were analyzed. The results identified an association between sciatica and the E5+15T>A polymorphism in IL6 (p = 0.007). A significant association was also seen in the IL6 haplotype analysis (-597 g>a, -572 g>c, -174 g>c and E5+15T>A). The association of the GGGA haplotype with the disease was highly significant (p = 0.0033).

Abstract Genetic factors have been shown to have an important role in intervertebral disc disease. The associations of known genetic risk factors and whole-body vibration, a proposed environmental risk factor, for intervertebral disc disease (IDD) were evaluated. Eleven variations in eight genes (COL9A2, COL9A3, COL11A2, IL1A, IL1B, IL6, MMP-3 and VDR) were genotyped in 150 male train engineers with an average of 21-year exposure to whole-body vibration and 61 male paper mill workers with no occupational exposure to vibration. The number of individuals belonging to the IDD group was significantly higher among train engineers (42% of train engineers vs. 17.5% of sedentary workers; p = 0.005). In addition, the IL1A-889T allele represented a risk factor for the IDD-phenotype. In order to clarify the role of genetic variations in the genes coding for several proinflammatory mediators, hundred fifty-five Finnish individuals with IDD were analyzed for mutations in the genes coding for inflammatory mediators IL-1α, IL-1β, IL-6 and TNF-α. In addition, sixteen single nucleotide polymorphisms (SNPs) in inflammatory mediator genes were genotyped. An association was identified between IDD and IL6 polymorphism +15T>A in exon 5 (p = 0.007). In addition, IL6 haplotype GGGA of -597G>A, -572G>C, -174G>C and +15T>A in exon 5 associated with IDD (p = 0.0033). A functional SNP in the CILP gene has been suggested to cause IDD in the Japanese population. This functional variation was analyzed in 243 Finnish IDD patients and 259 controls, and in 348 Chinese individuals with degenerative MRI findings and 343 Chinese individuals with normal MRI. No association was found in the Finnish and Chinese study populations. In order to reveal chromosomal susceptibility loci and new candidate gene(s) for IDD a genome-wide scan was performed on 14 Finnish families with 186 individuals. Genome-wide and fine mapping analysis provided maximum two-point LOD scores of 2.71, 2.36 and 2.04 for chromosomes 21, 4, and 6, respectively. Second fine mapping confirmed the susceptibility of chromosome 21. Two candidate genes, ADAMTS-1 and ADAMTS-5, were analyzed in the region suggesting linkage, leading to the identification of thirteen sequence variations. However, none of the variations were disease causing.

PURPOSE: The goal of this thesis research project is to evaluate and compare post-operative complications among patients, who underwent short and long segment Anterior Cervical Discectomy/Corpectomy and Fusion (ACDF/ACCF). METHODS: Retrospective cohort study design allowed for evaluation of series of variables (age, sex, diagnosis, general post-operative outcome, and complications) while comparing them between the short and long segment groups. RESULTS: Patients within both cohorts tended to experience similar complications, except pseudarthrosis and adjacent segment disease, which both were more prevalent in the long segment group. Diagnosis or short versus long segment length did not have an effect on the general post-operative outcome. One-level ACDF patients were younger than multilevel ACDF surgery patients. Dysphagia was more likely to occur in older patients, with the risk of dysphagia incidence increased by 7% with each year of patient’s age. CONCLUSIONS: Study indicated that longer segment ACDF/ACCF does not carry higher risk of complications incidence than short segment treatment. Further studies are advised to increase generalizability of these results.

Posterior lumbar spinal dynamic stabilisation devices are intended to relieve the pain of spinal segments while prolonging the lifespan of adjacent intervertebral discs. This study focuses on the design of such a device, one that has the correct stiffness to stabilise the spinal segment by the correct amount. An initial literature survey covers contemporary topics related to the lumbar spine. Included topics are lumbar anatomy and kinematics, pathology of degenerative disc disease and treatment thereof, other spinal disorders such as spondylolisthesis and spinal stenosis, as well as the complications associated with lumbar dynamic stabilisation. The influence of factors such as fatigue and wear, as well as the properties of appropriate biomaterials are considered when determining the basis of the device design and development. Stabilising the spinal segment begins with correct material selection and design. Various designs and biomaterials are evaluated for their stiffness values and other user requirements. The simplest design, a U-shaped spring composed of carbon fibre-reinforced poly-ether-ether-ketone (CFR-PEEK) and anchored by polyaxial titanium pedicle screws, satisfies the most critical user requirements. Acceptable stiffness is achieved, fatigue life of the material is excellent and the device is very imaging-friendly. Due to financial constraints, however, a simpler concept that is cheaper and easier to rapid prototype was chosen. This concept involves a construct primarily manufactured from the titanium alloy Ti6Al4V extra-low interstitial (ELI) and cobalt-chrome-molybdenum (CCM) alloys. The first rapid prototype was manufactured using an additive manufacturing process (3D-printing). The development of the device was performed in three main stages: design, verification and validation. The main goal of the design was to achieve an acceptable stiffness to limit the spinal segmental range of motion (ROM) by a determined amount. The device stiffness was verified through simple calculations. The first prototype’s stiffness was validated in force-displacement tests. Further validation, beyond the scope of this study, will include fatigue tests to validate the fatigue life of the production-ready device. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

Posterior lumbar spinal dynamic stabilisation devices are intended to relieve the pain of spinal segments while prolonging the lifespan of adjacent intervertebral discs. This study focuses on the design of such a device, one that has the correct stiffness to stabilise the spinal segment by the correct amount. An initial literature survey covers contemporary topics related to the lumbar spine. Included topics are lumbar anatomy and kinematics, pathology of degenerative disc disease and treatment thereof, other spinal disorders such as spondylolisthesis and spinal stenosis, as well as the complications associated with lumbar dynamic stabilisation. The influence of factors such as fatigue and wear, as well as the properties of appropriate biomaterials are considered when determining the basis of the device design and development. Stabilising the spinal segment begins with correct material selection and design. Various designs and biomaterials are evaluated for their stiffness values and other user requirements. The simplest design, a U-shaped spring composed of carbon fibre-reinforced poly-ether-ether-ketone (CFR-PEEK) and anchored by polyaxial titanium pedicle screws, satisfies the most critical user requirements. Acceptable stiffness is achieved, fatigue life of the material is excellent and the device is very imaging-friendly. Due to financial constraints, however, a simpler concept that is cheaper and easier to rapid prototype was chosen. This concept involves a construct primarily manufactured from the titanium alloy Ti6Al4V extra-low interstitial (ELI) and cobalt-chrome-molybdenum (CCM) alloys. The first rapid prototype was manufactured using an additive manufacturing process (3D-printing). The development of the device was performed in three main stages: design, verification and validation. The main goal of the design was to achieve an acceptable stiffness to limit the spinal segmental range of motion (ROM) by a determined amount. The device stiffness was verified through simple calculations. The first prototype’s stiffness was validated in force-displacement tests. Further validation, beyond the scope of this study, will include fatigue tests to validate the fatigue life of the production-ready device. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

Einleitung: Der Verdacht, dass Hunde mit einem Bandscheibenvorfall eine Prädisposition für die Entstehung einer Pankreatitis haben könnten, wurde in der Veterinärmedizin bereits in den frühen 1980er Jahren diskutiert. Trotz dieser bereits vor vielen Jahren erhobenen Vermutungen, wurde der Zusammenhang zwischen der Entstehung einer Pankreatitis und einem zeitgleich vorliegenden Bandscheibenvorfall auch im Hinblick auf mögliche Risikofaktoren wie dem Einfluss der Narkose oder dem Einsatz von Medikamenten (v. a. Glukokortikoide und nichtsteroidale Antiphlogistika) bisher nicht näher untersucht. Ziele der Untersuchungen: Im Rahmen der vorliegenden prospektiven Studie sollte untersucht werden, ob Bandscheibenvorfälle ein Risikofaktor für die Entstehung einer Pankreatitis beim Hund darstellen. Ferner sollte geklärt werden, ob die Narkose und die Gabe von Glukokortikoiden und/oder nichtsteroidalen Antiphlogistika zusätzlich das Risiko der Entstehung einer Pankreatitis bei Hunden mit einem Bandscheibenvorfall erhöhen. Material und Methoden: Insgesamt wurden 106 Hunde, bei denen aufgrund der klinischen Symptome der Verdacht einer Rückenmarksläsion bestand, an fünf aufeinander folgenden Tagen klinisch untersucht. Besonderes Augenmerk wurde hierbei auf Symptome gelegt, welche typischerweise bei Pankreatitiden zu beobachten sind (reduziertes Allgemeinbefinden, Schwäche, Anorexie, dolentes Abdomen, Vomitus, Regurgitieren, Diarrhoe, Fieber, Dehydratation). Ferner wurde am Tag 0 und Tag 4 der stationären Aufnahme die Konzentration der caninen pankreasspezifischen Lipase im Serum gemessen (Spec cPL und Snap cPL). Am Tag 0 wurde von dem Vorliegen einer Pankreatitis ausgegangen, wenn klinische Befunde im Sinne einer Pankreatitis sowie eine abnorm erhöhte Konzentration der caninen pankreasspezifischen Lipase im Serum (>400 μg/L) auffällig waren. Am Tag 4 erfolgte zudem eine sonographische Untersuchung des Abdomens. Somit basierte die Diagnosestellung einer Pankreatitis an diesem Tag auf dem Vorliegen von zwei der folgenden drei Kriterien: klinische Befunde im Sinne einer Pankreatitis, abnorm erhöhte Konzentration der caninen pankreasspezifischen Lipase im Serum, sonographische Hinweise für das Vorliegen einer Pankreatitis. Im Rahmen der statistischen Auswertung wurden zudem auch Patienten erfasst, welche in einem oder in mehreren der oben genannten Kriterien ein fragliches Ergebnis aufwiesen. Entsprechend ihrer neurologischen Ausfallserscheinungen sowie der Befunde im Rahmen der bildgebenden Diagnostik (Myelographie, Computertomographie, Kernspintomographie) wurden die Patienten in eine der folgenden drei Untersuchungsgruppen eingeteilt: 1. Hunde mit einem chirurgisch versorgten Bandscheibenvorfall (n = 71) 2. Hunde mit einem konservativ therapierten Bandscheibenvorfall (n = 20) und 3. Hunde mit einer akuten intramedullären Läsion (n = 15). Die statistische Auswerte erfolgte aufgrund der geringen Stichprobengrößen vorwiegend deskriptiv. Die Daten wurden mittels des Shapiro-Wilk-Tests auf Normalverteilung überprüft, die durchgeführten Gruppenvergleiche erfolgten unter Verwendung des Kruskal-Wallis und Mann-Whitney-U-Tests. Zudem wurden die betrachteten Merkmale mit dem Fisher Test und dem Chi-Quadrat-Test auf Unabhängigkeit überprüft. Das Signifikanzniveau wurde für alle Tests mit p < 0,05 festgelegt. Ergebnisse: Basierend auf den klinischen Symptomen und der Konzentration der caninen pankreasspezifischen Lipase im Serum konnte insgesamt am Tag 0 bei vier Hunden (3,8 %) eine Pankreatitis diagnostiziert werden. Am Tag 4 waren es, basierend auf den drei Kriterien, welche für die Diagnosestellung einer Pankreatitis herangezogen werden, insgesamt acht Patienten (7,5 %). Hunde mit einem Bandscheibenvorfall (chirurgisch beziehungsweise konservativ therapiert) wiesen am Tag 0 beziehungsweise Tag 4 in 4,3 % (n = 4) beziehungsweise 7,7 % (n = 7) der Fälle eine Pankreatitis auf. Aufgrund der geringen Häufigkeiten in den einzelnen Untersuchungsgruppen, war eine Berechnung eines signifikanten Unterschieds zwischen den Gruppen nicht möglich. Hinsichtlich einer möglichen Korrelation zwischen einer Narkose und der Entstehung einer Pankreatitis bei Hunden mit einer Rückenmarksläsion konnte kein signifikanter Zusammenhang festgestellt werden. Auch die Gabe von Glukokortikoiden und/oder nichtsteroidalen Antiphlogistika hatte hier keinen signifikanten Einfluss auf die Entstehung einer Pankreatitis. Schlussfolgerung: Vergleicht man die Ergebnisse der vorliegenden Studie mit der in der Literatur angegebenen Prävalenz für akute Pankreatitiden beim Hund (0,7-3,5 %), so kann geschlussfolgert werden, dass eine Rückenmarksläsion, insbesondere ein Bandscheibenvorfall, als Risikofaktor für die Entstehung einer akuten Pankreatitis beim Hund in Betracht gezogen werden muss. Demgegenüber erhöhen weder die Narkose noch die Gabe von Glukokortikoiden und/oder nichtsteroidalen Antiphlogistika zusätzlich das Risiko der Entstehung einer Pankreatitis bei Hunden mit einer Rückenmarksläsion. / Objective: The suspicion that dogs with intervertebral disc disease are at greater risk of developing pancreatitis is being discussed in veterinary medicine since the early 1980s. So far no study has been published examining the correlation between intervertebral disk disease and the development of pancreatitis in dogs, especially in combination with general anaesthesia and anti-inflammatory medication (glucocorticoids and/or nonsteroidal anti-inflammatory drugs). The aim of this study was therefore 1) to evaluate intervertebral disk disease as possible risk factor of pancreatitis and 2) to ascertain if general anaesthesia and the administration of glucocorticoids and/or nonsteroidal anti-inflammatory drugs further increase the risk of pancreatitis in dogs with intervertebral disk disease. Material and methods: One hundred and six dogs with symptoms associated with spinal cord injury were clinically examined over a period of five days. Special attention was payed to symptoms usually seen with pancreatitis such as anorexia, vomitus and abdominal pain. Furthermore the concentration of canine pancreatic lipase in the blood serum was measured with Spec cPL and Snap cPL at day 0 and day 4 after admission. At day 0 the diagnosis of pancreatitis was based on clinical symptoms associated with pancreatitis in combination with an increased concentration of canine pancreatic lipase in the blood serum (>400 μg/L). A sonography of the pancreas was performed at day 4 to evaluate the organ itself and the surrounding tissue for lesions associated with pancreatitis. Therefore the diagnosis of pancreatitis at day 4 was based on positive results in at least two of the three following criteria: symptoms associated with pancreatitis, elevation of the concentration of canine pancreatic lipase in the blood serum, sonographic changes of the pancreas parenchyma and the surrounding tissue associated with pancreatitis. For statistical analysis questionable results in one or more of these criteria were also documented. According to the neurologic symptoms and the findings of diagnostic imaging (myelography, computed tomography and magnetic resonance imaging), dogs were categorized in one of the following groups: 1. dogs with surgically treated intervertebral disk disease (n = 71), 2. dogs with medically treated intervertebral disk disease (n = 20), 3. dogs with an acute intramedullary lesion (n = 15). Due to the small sample size, statistics were primarily performed descriptively. Data were tested for normal distribution using the Shapiro-Wilk test. If Group comparisons were feasible, they were performed using the Kruskal-Wallis test and the Mann-Whitney-U test. Fisher test and the Chi-Square test were used to test for association between group affiliation and possible risk factors for the development of pancreatitis. A value of P < 0.5 was considered significant for all analysis. Results: Based on clinical symptoms and an elevated concentration of the canine pancreatic lipase (> 400μg/l) at day 0, four dogs (3.8 %) were diagnosed with pancreatitis. According to the clinical symptoms, the concentration of the canine pancreatic lipase and sonographic changes, a total number of eight dogs (7.5 %) were diagnosed with pancreatitis at day 4. Considering only the dogs with intervertebral disk disease (surgically and medically treated) 4.3 % (n = 4) and 7.7 % (n = 7) were diagnosed with pancreatitis at day 0 and day 4, respectively. Due to the small sample size, the calculation of significant differences between the three subgroups was not feasible. There was no significant correlation between general anaesthesia and the development of pancreatitis. Furthermore, the administration of glucocorticoids and/or nonsteroidal anti-inflammatory drugs is not significantly associated with the genesis of pancreatitis.

This thesis is an investigation of the access provided to the vertebral canal in dogs by the hemilaminectomy and mini-hemilaminectomy surgical techniques using computed tomography (CT), and the completeness of evacuating extruded material in dogs with intervertebral disc (IVD) extrusion using magnetic resonance imaging (MRI). Hemilaminectomy and mini-hemilaminectomy were performed on opposite sides of the spine at T11-T12, T13-L1, and L2-L3 in 10 cadavers. Measurements of the vertebral canal height, defect height, and any dorsal and ventral remnants of the vertebral arch were obtained by CT. A covariate analysis was used to compare measurements with the surgical technique, surgical site, and side of the vertebral column. Defect height was greater with hemilaminectomy due to a smaller dorsal lamina remnant. There was no statistical difference in the height of the ventral remnant, or with surgical site. Nineteen prospectively recruited dogs with suspected IVD extrusion were randomly assigned to hemilaminectomy (10 dogs) or mini-hemilaminectomy (9 dogs) groups. Intervertebral disc extrusion was identified pre-operatively with MRI and later confirmed surgically, and immediate post-operative MRI was performed at the surgical site. The volume of extruded IVD material pre- and post-operative was calculated from transverse T2 images. Although residual IVD material was present in post-operative images from all dogs in the hemilaminectomy group and only 4 in the mini-hemilaminectomy group, there was no statistically significant difference between the proportionate volumes of material removed by either technique. The median residual volume with hemilaminectomy was 13.6% (confidence interval: 7.8 – 23.6%), and with mini-hemilaminectomy was 7.7% (4.3 – 13.8%). The results of this study confirm that the difference in the defect height between techniques is related to the removal of the articular processes creating a larger defect along the dorsal vertebral canal, while no difference in access to the ventral canal was observed. No effect of vertebral site was detected suggesting neither procedure provides an advantage over the other due to location of the lesion along the thoracolumbar spine. Residual extruded IVD material occurs with both techniques; while no statistical difference was noted, a larger population should be examined. / Ontario Veterinary College Pet Trust

abstract: Intervertebral Disc Degeneration (IVDD) is a complex phenomenon characterizing the desiccation and structural compromise of the primary joint in the human spine. The intervertebral disc (IVD) serves to connect vertebral bodies, cushion shock, and allow for flexion and extension of the vertebral column. Often presenting in the 4th or 5th decades of life as low back pain, this disease was originally believed to be the result of natural “wear and tear” coupled with repetitive mechanical insult, and as such most studies focus on patients between 40 and 50 years of age. Research over the past two decades, however, has demonstrated that environmental factors have only a modest effect on disc degeneration, with genetic influences playing a much more substantial role. Extensive research has focused on this process, though definitive risk factors and a clear pathophysiology have proven elusive. The aim of this study was to assemble a cohort of patients exhibiting definitive signs of degeneration who were well below the average age of presentation, with minimal or no exposure to suspected environmental risk factors and to conduct a targeted genome analysis in an attempt to elucidate a common genetic component. Through whole genome sequencing and analysis, the results corroborated findings in a previous study, as well as demonstrated a potential connection and influence between mutations found in IVD structural or functional genes, and the provocation of IVDD. Though the sample size was limited in scale and age, these findings suggest that further IVDD research into the association of variants in collagen, aggrecan and the insulin-like growth factor receptor genes of young patients with an early presentation of disc degeneration and minimal exposure to suspected risk factors is merited. / Dissertation/Thesis / Masters Thesis Biology 2016

Foram avaliados 25 cães portadores de discopatia cervical aos exames radiográficos simples, mielografia e tomografia computadorizada. A dor foi o principal sinal clínico em 64% dos casos. Os animais com raça definida foram os mais acometidos (85%), tendo maior incidência da raça Teckel. A faixa etária mais acometida foi entre 7-9 anos (72%). O exame radiográfico simples indicou aspectos compatíveis com extrusão em 14 observações. A mielografia diagnosticou 15 extrusões, 18 protrusões e 4 hérnias de disco e forneceu informações quanto ao grau de compressão medular e extensão das lesões. A tomografia computadorizada (TC) indicou 16 extrusões, 22 protrusões e 3 hérnias de disco. O espaço de C2-3 foi o mais acometido. A TC permitiu o diagnóstico de extrusões calcificadas, mesmo na presença de pouca quantidade ou ausência de meio de contraste e indicou com precisão o grau de compressão medular, a extensão e principalmente, a localização das lesões. Concluiu-se com este estudo que os três exames se complementam e constituem importantes ferramentas para o planejamento clínico-cirúrgico. / Twenty-five dogs with disc disease in cervical spine were evaluated by radiological and computed tomographic exams. The most common clinical signs were neck pain present in 64% of the dogs. Of the animals 85% were pure breed, amongst them Teckel were most frequent (28%). The most cases occurred in animals between seven and nine years. C2-3 was the preferred site of cervical involvement. Radiographic plain indicated fourteen extrusion. Myelography demonstrated fifteen extrusions, eighteen protrusions and four disc hernias and indicated spinal cord grade compression and lesions extension. Computed tomographic (CT) demonstred sixteen extrusions, twenty-two protrusions and three disc hernias. The CT showed to be more sensitive for soft tissue calcification, and his superior contrast resolution allowed visualization small quantities of contrast material in the subarachnoid space and indicated with precision the site and extension of lesions as well as the degree of spinal cord compression. The three exams are complementary and give valuable information for clinical and chirurgical procedures.

Foram avaliados 25 cães portadores de discopatia cervical aos exames radiográficos simples, mielografia e tomografia computadorizada. A dor foi o principal sinal clínico em 64% dos casos. Os animais com raça definida foram os mais acometidos (85%), tendo maior incidência da raça Teckel. A faixa etária mais acometida foi entre 7-9 anos (72%). O exame radiográfico simples indicou aspectos compatíveis com extrusão em 14 observações. A mielografia diagnosticou 15 extrusões, 18 protrusões e 4 hérnias de disco e forneceu informações quanto ao grau de compressão medular e extensão das lesões. A tomografia computadorizada (TC) indicou 16 extrusões, 22 protrusões e 3 hérnias de disco. O espaço de C2-3 foi o mais acometido. A TC permitiu o diagnóstico de extrusões calcificadas, mesmo na presença de pouca quantidade ou ausência de meio de contraste e indicou com precisão o grau de compressão medular, a extensão e principalmente, a localização das lesões. Concluiu-se com este estudo que os três exames se complementam e constituem importantes ferramentas para o planejamento clínico-cirúrgico. / Twenty-five dogs with disc disease in cervical spine were evaluated by radiological and computed tomographic exams. The most common clinical signs were neck pain present in 64% of the dogs. Of the animals 85% were pure breed, amongst them Teckel were most frequent (28%). The most cases occurred in animals between seven and nine years. C2-3 was the preferred site of cervical involvement. Radiographic plain indicated fourteen extrusion. Myelography demonstrated fifteen extrusions, eighteen protrusions and four disc hernias and indicated spinal cord grade compression and lesions extension. Computed tomographic (CT) demonstred sixteen extrusions, twenty-two protrusions and three disc hernias. The CT showed to be more sensitive for soft tissue calcification, and his superior contrast resolution allowed visualization small quantities of contrast material in the subarachnoid space and indicated with precision the site and extension of lesions as well as the degree of spinal cord compression. The three exams are complementary and give valuable information for clinical and chirurgical procedures.