Entire Spinal Cord Research Articles

Subacute combined degeneration without nutritional anemia

Subacute combined degeneration (SCD) is a rare neurological complication of cobalamin deficiency, characterized by demyelination of the dorsal and lateral spinal cord. The diagnosis and treatment of SCD can be delayed if a patient does not present with clear clinical and laboratory signs of nutritional anemia, which has a marked effect on neurological recovery. We report a 62-year-old man with SCD with a history of gastric cancer and chronic alcoholism who presented with ataxia, gait disturbance, urinary incontinence, and limb weakness, but without other clinical or laboratory signs of cobalamin deficiency. The SCD diagnosis was confirmed by 3-Tesla MRI, which showed intramedullary signal alteration in the posterior columns of the entire spinal cord.

Functional MRI of the thoracic spinal cord during vibration sensation

To demonstrate that it is possible to acquire accurate functional magnetic resonance images from thoracic spinal cord neurons. The lower thoracic spinal dermatomes (T7-T11) on the right side of the body were mechanically stimulated by vibration for 15 participants. Neuronal responses to vibration sensation were measured in the thoracic spinal cord using a HASTE sequence on a 3 Tesla MRI system. Signal increases were observed in the corresponding lower thoracic spinal cord segments ipsilateral to the side of stimulation in the dorsal aspect of the spinal cord. This is the first study to provide proof of principle that functional imaging of the entire thoracic spinal cord is possible, by detecting neuronal activity in the thoracic spinal cord during sensory stimulation using spinal fMRI.

Delayed post-traumatic spinal cord infarction in an adult after minor head and neck trauma: a case report

IntroductionDelayed post-traumatic spinal cord infarction is a devastating complication described in children. In adults, spinal cord ischemia after cardiovascular interventions, scoliosis correction, or profound hypotension has been reported in the literature. However, delayed spinal cord infarction after minor head trauma has not been described yet.Case presentationWe report the case of a 45-year-old Hispanic man who had a minor head trauma. He was admitted to our hospital because of paresthesias in his hands and neck pain. A radiological workup showed cervical spinal canal stenosis and chronic cervical spondylotic myelopathy. Twelve hours after admission, our patient became unresponsive and, despite full resuscitation efforts, died. The autopsy revealed spinal cord necrosis involving the entire cervical spinal cord and upper thoracic region.ConclusionsThis case illustrates the extreme fragility of spinal cord hemodynamics in patients with chronic cervical spinal canal stenosis, in which any further perturbations, such as cervical hyperflexion related to a minor head injury, can have catastrophic consequences. Furthermore, the delayed onset of spinal cord infarction in this case shows that meticulous maintenance of blood pressure in the acute post-traumatic period is of paramount importance, even in patients with minimal post-traumatic symptoms.

Fully automatic stitching of diffusion tensor images in spinal cord

Diffusion tensor imaging (DTI) has become an important tool for studying the spinal cord pathologies. To enable high resolution imaging for modern studies, the DTI technique utilizes a small field of view (FOV) to capture partial human spinal cords. However, normal aging and many other diseases which affect the entire spinal cord increase the desire of acquiring the continuous full-view of the spinal cord. To overcome this problem, this paper presents a novel pipeline for automatic stitching of three-dimensional (3D) DTI of different portions of the spinal cord. The proposed technique consists of two operations, e.g. feature-based registration and adaptive composition to stitch every source image together to create a panoramic image. In the feature-based registration process, feature points are detected from the apparent diffusion coefficient map, and then a novel feature descriptor is designed to characterize feature points directly from a tensor neighborhood. 3D affine transforms are achieved by determining the correspondence matching. In the adaptive composition process, an effective feathering approach is presented to compute the tensors in the overlap region by the Log-Euclidean metrics. We evaluate the algorithm on real datasets from one healthy subject and one adolescent idiopathic scoliosis (AIS) patient. The colored FA maps and fiber tracking results show the effectiveness and accuracy of the proposed stitching framework.

Biplanar MRI for the assessment of the spinal cord in multiple sclerosis

Objective: To investigate the entire spinal cord (SC) of multiple sclerosis (MS) patients with biplanar MRI and to relate these MRI findings to clinical functional scores. Methods: Two hundred and two patients (140 women, 62 men 24–74 years, Expanded Disability Status Scale (EDSS) scores 0–7.5) were investigated clinically and with biplanar MRI. Sagittal and axial proton density weighted (PDw) and T2 weighted (T2w) images of the whole SC were obtained employing parallel imaging. Data were analyzed by consensus reading using a standardized reporting scheme. Different combinations of findings were compared to EDSS scores with Spearman’s rank correlation coefficient (ρ). Results: The combined analysis of sagittal and axial planes demonstrated slightly differing results in 97/202 (48%) patients. There were 9% additional lesions identified, leading to a higher lesion count in 28% of these patients, but also rejection of equivocal abnormality leading to a lower lesion count in 11% of patients. Considering both sagittal and axial images, SC abnormalities were found in 167/202 (83%) patients. When compared with EDSS scores, the combination of focal lesions, signs of atrophy and diffuse abnormalities showed a moderate correlation (ρ=0.52), that precludes its use for individual patient assessment. Conclusion: Biplanar MRI facilitates a comprehensive identification, localization, and grading of pathological SC findings in MS patients. This improves the confidence and utility of SC imaging.

High frequency of spinal involvement in patients with basal subarachnoid neurocysticercosis

To determine the frequency of spinal neurocysticercosis (NCC) in patients with basal subarachnoid NCC compared with that in individuals with viable limited intraparenchymal NCC (≤20 live cysts in the brain). We performed a prospective observational case-control study of patients with NCC involving the basal cisterns or patients with only limited intraparenchymal NCC. All patients underwent MRI examinations of the brain and the entire spinal cord to assess spinal involvement. Twenty-seven patients with limited intraparenchymal NCC, and 28 patients with basal subarachnoid NCC were included in the study. Spinal involvement was found in 17 patients with basal subarachnoid NCC and in only one patient with limited intraparenchymal NCC (odds ratio 40.18, 95% confidence interval 4.74-340.31; p < 0.0001). All patients had extramedullary (intradural) spinal NCC, and the lumbosacral region was the most frequently involved (89%). Patients with extensive spinal NCC more frequently had ventriculoperitoneal shunt placement (7 of 7 vs 3 of 11; p = 0.004) and tended to have a longer duration of neurologic symptoms than those with regional involvement (72 months vs 24 months; p = 0.062). The spinal subarachnoid space is commonly involved in patients with basal subarachnoid NCC, compared with those with only intraparenchymal brain cysts. Spinal cord involvement probably explains serious late complications including chronic meningitis and gait disorders that were described before the introduction of antiparasitic therapy. MRI of the spine should be performed in basal subarachnoid disease to document spinal involvement, prevent complications, and monitor for recurrent disease.

Contrasting disease patterns in seropositive and seronegative neuromyelitis optica: A multicentre study of 175 patients

BackgroundThe diagnostic and pathophysiological relevance of antibodies to aquaporin-4 (AQP4-Ab) in patients with neuromyelitis optica spectrum disorders (NMOSD) has been intensively studied. However, little is known so far about the clinical impact of AQP4-Ab seropositivity.ObjectiveTo analyse systematically the clinical and paraclinical features associated with NMO spectrum disorders in Caucasians in a stratified fashion according to the patients' AQP4-Ab serostatus.MethodsRetrospective study of 175 Caucasian patients (AQP4-Ab positive in 78.3%).ResultsSeropositive patients were found to be predominantly female (p < 0.0003), to more often have signs of co-existing autoimmunity (p < 0.00001), and to experience more severe clinical attacks. A visual acuity of ≤ 0.1 during acute optic neuritis (ON) attacks was more frequent among seropositives (p < 0.002). Similarly, motor symptoms were more common in seropositive patients, the median Medical Research Council scale (MRC) grade worse, and MRC grades ≤ 2 more frequent, in particular if patients met the 2006 revised criteria (p < 0.005, p < 0.006 and p < 0.01, respectively), the total spinal cord lesion load was higher (p < 0.006), and lesions ≥ 6 vertebral segments as well as entire spinal cord involvement more frequent (p < 0.003 and p < 0.043). By contrast, bilateral ON at onset was more common in seronegatives (p < 0.007), as was simultaneous ON and myelitis (p < 0.001); accordingly, the time to diagnosis of NMO was shorter in the seronegative group (p < 0.029). The course of disease was more often monophasic in seronegatives (p < 0.008). Seropositives and seronegatives did not differ significantly with regard to age at onset, time to relapse, annualized relapse rates, outcome from relapse (complete, partial, no recovery), annualized EDSS increase, mortality rate, supratentorial brain lesions, brainstem lesions, history of carcinoma, frequency of preceding infections, oligoclonal bands, or CSF pleocytosis. Both the time to relapse and the time to diagnosis was longer if the disease started with ON (p < 0.002 and p < 0.013). Motor symptoms or tetraparesis at first myelitis and > 1 myelitis attacks in the first year were identified as possible predictors of a worse outcome.ConclusionThis study provides an overview of the clinical and paraclinical features of NMOSD in Caucasians and demonstrates a number of distinct disease characteristics in seropositive and seronegative patients.

Characterization of DTI Indices in the Cervical, Thoracic, and Lumbar Spinal Cord in Healthy Humans

The aim of this study was to characterize in vivo measurements of diffusion along the length of the entire healthy spinal cord and to compare DTI indices, including fractional anisotropy (FA) and mean diffusivity (MD), between cord regions. The objective is to determine whether or not there are significant differences in DTI indices along the cord that must be considered for future applications of characterizing the effects of injury or disease. A cardiac gated, single-shot EPI sequence was used to acquire diffusion-weighted images of the cervical, thoracic, and lumbar regions of the spinal cord in nine neurologically intact subjects (19 to 22 years). For each cord section, FA versus MD values were plotted, and a k-means clustering method was applied to partition the data according to tissue properties. FA and MD values from both white matter (average FA = 0.69, average MD = 0.93 × 10−3 mm2/s) and grey matter (average FA = 0.44, average MD = 1.8 × 10−3 mm2/s) were relatively consistent along the length of the cord.

Pattern of 18F-FDG Uptake in the Spinal Cord in Patients With Non-Central Nervous System Malignancy

Retrospective review. To (1) propose a standard method to quantitate 2-deoxy-2-[18F]-fluoro-D-glucose (18F-FDG) uptake in the spinal cord and (2) use this methodology to retrospectively characterize the pattern of uptake within the entire spinal cord using whole-body positron emission tomography/computed tomography (PET/CT) imaging. A physiologic understanding of glucose metabolism within the spinal cord may provide insight regarding infectious, inflammatory, vascular, and neoplastic spinal cord diseases. Institutional review board approval was obtained. A total of 131 consecutive whole-body PET/CT studies from July to August 2004 were reviewed, and using exclusionary criteria of: (1) severe spinal arthropathy or curvature, (2) motion artifact, (3) canal hardware, (4) spinal tumor, and (5) marrow hyperplasia, 92 studies of neurologically intact patients (49 men and 43 women) were selected for a retrospective review of spinal cord 18F-FDG activity. The transaxial CT was used to define the canal and circular regions of interests were placed within the canal at the level of the vertebral body midpoint from C1 to L3. Region of interest total count, area, and maximum standardized uptake value (SUVmax) were recorded. Measurements at L5 served as an internal control. For comparative analysis, the cord-to-background (CTB) ratio was defined as spinal cord SUVmax to L5 SUVmax. Mean CTB decreased along each spinal level from cranial to caudal (P < 0.001). Significant relative increases were observed at the T11-T12 vertebral body levels (P < 0.001). Although insignificant, a relative increase was observed at C4. No significant interactions of age or sex on CTB were observed. The pattern of 18F-FDG uptake within the spinal cord, observed in patients with non-central nervous system malignancy, may be helpful in understanding glucose physiology of spinal cord diseases and warrants further research.

P3.10 Intramuscular AAV9 administration enables transgene delivery to motor neurons in the whole spinal cord: Therapeutic application in a SMA mouse model

We recently showed that a single intravenous injection of an optimized SMN-encoding scAAV9 (scAAV9-SMNopti) rescued a Spinal Muscular Atrophy (SMA) mouse model. Intramuscular (IM) injection of AAV1–AAV8 has been reported to mediate a moderate spinal cord transduction through axonal retrograde transport. Given the remarkable effectiveness of scAAV9 for motor neurons (MNs) gene transfer, we analyzed whether IM injection of this vector was efficacious to target MNs throughout the entire spinal cord.

Infratentorial craniospinal irradiation for von Hippel-Lindau: a retrospective study supporting a new treatment for patients with CNS hemangioblastomas

Patients with von Hippel-Lindau (VHL) syndrome with diffuse CNS hemangioblastomas have morbidity related to their disease and require a lifetime of surgical resections. Ninety-seven percent of tumors progress, and 5-year surgery rates are 20%-60%. Stereotactic radiosurgery and fractionated radiotherapy have had limited success. For the first time, we have used infratentorial craniospinal radiation therapy (ICSRT) for VHL patients with CNS hemangioblastomas. Consecutive VHL patients treated at the National Institutes of Health with radiographic evidence of hemangioblastomas were included if they received ICSRT. Patients underwent neurologic examinations and imaging at 3- to 12-month intervals. Seven patients with 84 hemangioblastomas met eligibility criteria. ICSRT was commonly administered to 43.2 Gy in 24 fractions. Mean pre-ICSRT tumor volume was 5.48 cm(3). At a mean follow-up of 73.8 months, mean post-ICSRT tumor volume was 6.87 cm(3), and 91 tumors were identified. Complete radiographic resolution was achieved in 17.9% of lesions. Although many patients were no longer optimal surgical candidates, only 4 surgeries were needed for symptomatic lesions after ICSRT, compared with 33 prior. Acute toxicity was mild and no patient developed grade ≥1 late spinal cord toxicity according to the criteria of the Radiation Therapy Oncology Group/European Organisation for Research and Treatment of Cancer, despite the high dose that the entire spinal cord received. Clinical and radiographic stability or resolution was demonstrated in the majority of tumors. Tumor growth rate in this study was less than reported in natural history studies, and the rate of surgical intervention was reduced. ICSRT was well tolerated, can decrease hemangioblastoma growth rate, and is a potential therapeutic option for VHL patients that warrants further investigation.

Genetic strategies to study TDP-43 in rodents and to develop preclinical therapeutics for amyotrophic lateral sclerosis.

The neuropathological hallmark of the majority of amyotrophic lateral sclerosis (ALS) and a class of frontotemporal lobar degeneration is ubiquitinated cytoplasmic aggregates composed of transactive response DNA binding protein 43 kDa (TDP-43). Genetic manipulation of TDP-43 in animal models has been used to study the protein's role in pathogenesis. Transgenic rodents for TDP-43 have recapitulated key aspects of ALS such as paralysis, loss of spinal motor neurons and muscle atrophy. Viral vectors are an alternate approach to express pathological proteins in animals. Use of the recombinant adeno-associated virus vector serotype 9 has permitted widespread transgene expression throughout the central nervous system after intravenous administration. Expressing TDP-43 in rats with this method produced a phenotype that was consistent with and similar to TDP-43 transgenic lines. Increased levels of TDP-43 in the nucleus are toxic to neurons and sufficient to produce ALS-like symptoms. Animal models based on TDP-43 will address the relationships between TDP-43 expression levels, pathology, neuronal loss, muscle atrophy, motor function and causative mechanisms of disease. New targets that modify TDP-43 function, or targets from previous ALS models and other models of spinal cord diseases, could be tested for efficacy in the recent rodent models of ALS based on TDP-43. The vector approach could be an important therapeutic channel because the entire spinal cord can be affected from a one-time peripheral administration.

Characterization of three synuclein genes in Xenopus laevis

The synuclein family consists of three small intracellular proteins mainly expressed in neural tissues, and has been associated with human neurodegenerative diseases. We have examined the spatial and temporal expression patterns of three synuclein genes during embryogenesis of Xenopus laevis. The Xenopus synucleins were firstly expressed in the developing nervous system at the tail bud stages. At tadpole stages, Xenopus snca was expressed in the brain, branchial arch and somite, and sncbb signals were detected in entire brain and spinal cord. However, sncg was only expressed in the peripheral nervous system including trigeminal nerve and dorsal root ganglion. RT-PCR indicated that expression of synucleins was up-regulated at the end of neurulation, and then maintained at later examined stages. Our study provides the spatiotemporal expression patterns of the synuclein family genes in Xenopus embryos, and forms a basis for further functional analysis of synucleins.

SU-E-T-488: Treatment of a Unique CNS Patient with Tomotherapy

Purpose: We describe a whole spinal cord, cauda equine, and brainstem radiation treatment using an in‐house developed tomotherapy approach for a unique patient diagnosed with an extramedullary spinal melanocytoma with leptomeningeal seeding, treated with 48.6 Gy in 28 fractions. Methods and Materials: Given that the prescribed dose is within the range of tolerance to the spinal cord, tomotherapy was chosen to take advantage of the superior dose uniformity achievable with this technology and ability to deliver modulated radiotherapy in a single treatment to a long volume. The patient was treated supine and immobilized with a thermoplastic mask for the head and shoulders and a long Vac‐Lok bag for the body. The CTV consisted of the entire spinal cord, thecal sac to the level of S2 and brainstem. A 1 cm margin was applied to create the PTV. Jaws, pitch and the modulation factor were set to 5 cm, 0.43 and 2.5, respectively. Before each treatment, the treated volume was imaged for setup verification using the integrated megavoltage CT (MVCT). Weekly the patient was also imaged post‐ treatment to confirm setup stability. Results: The patient is finishing treatment at the time of abstract submission. A highly conformal dose distribution was created with doses to the organs at risk within their tolerance limits. The beam on time was 17 minutes. Patient setup proved to be trouble‐free and reproducible. The total patient‐on‐the‐bed time was approximately one hour. The 1 cm PTV margin was adequate according to pre‐ and post‐treatment MVCT image analysis. Conclusions: Tomotherapy is a safe and effective tool for treating long CNS volumes to high dose. It allows avoiding junctions and sparing healthy CNStissue and other organs at risk. A relatively simple immobilization technique used for this patient proved to be stable and reproducible with a 1 cm PTV margin.

An unusual case of a rare disease pelvic arteriovenous malformation concealing a spinal dural arteriovenous fistula

Dear Editor,Due to the nonspecific nature of clinical symptoms, there isa long delay between onset of first symptoms and definitivediagnosis of SDAVF often. We report the case of a patientwith congestive myelopathy believed to be caused by alarge pelvic arteriovenous malformation, which concealed athoracic SDAVF.Case reportA 62-year-old man presented with progressive myelopathy.T2-weighted MRI of the entire spinal cord revealed a highintramedullary signal from Th7-Th9, accompanied byintradural dilated perimedullary vessels. These finding areconsistent with dural arteriovenous fistulas; therefore,selective spinal angiograms (DSA) were performed. How-ever, two DSAs failed to reveal any SDAVF; but, a largepelvic arteriovenous malformation (pAVM), with feedersfrom the internal iliac arteries and massively dilateddraining veins into the inferior caval vein, was incidentallyfound. Following the assumption that the pAVM waspossibly obstructing the drainage of the spinal veins therebycausing congestive damage to the spinal cord, it wasdecided to perform a partial embolization of the AVMbecause a complete embolization or surgical removal wasbelieved to harm the patient. However, several partialembolizations failed to relieve his symptoms. Thereafter,the patient was referred to our department for re-evaluation.A further spinal DSA failed to detect any SDAVFs.Therefore, we performed a complete embolization of thepAVM followed by surgical shunt disconnection. Hissymptoms regressed.Two months later, his symptoms progressed again. MRIshowed congestive changes of the cord. A pelvic angio-gram showed no revascularization of the pAVM. By then,due to the matching clinical signs and MRI findings, anSDAVF became highly suspicious again. However, aSDAVF was not detected by two complete spinal DSAs.Finally, using a multidetector computed tomographicangiography (MDCTA), at Th3 an arteriovenous fistulawas revealed. The feeder was from the sixth spinal artery,which sprouted from a bronchial artery that originated fromthe thoracic aorta a few millimeters above the seventhspinalartery(Fig.1). Therefore, this bronchial artery was notdetected by spinal angiography because the neuroradiologist,not expecting such an anatomic anomaly, was able tocatheterize the seventh spinal artery, only. The MDCTAfinding was then confirmed by a targeted DSA (Fig. 1).Finally, the fistula was clipped and the patient’ssymptomswere regressive.Six months later, the patient presented again with aprogressive myelopathy. MRI revealed an enlargement ofthe T2-signal intensity of the thoracic spine but without anyperimedullary dilated veins. A MDCTA did not show anysigns of a SDAVF recurrence. CSF and blood laboratoryexams found no evidence for any inflammation or

Neuroprotection by Gene Therapy Targeting Mutant SOD1 in Individual Pools of Motor Neurons Does not Translate Into Therapeutic Benefit in fALS Mice

A major challenge in neurological gene therapy is delivery of the transgene to sufficient cell numbers in an atraumatic manner. This is particularly difficult for motor neuron (MN) diseases that have cells located across the entire spinal cord, brain stem, and cortex. We have used the familial mouse model of amyotrophic lateral sclerosis (ALS) to examine the feasibility of body-wide intramuscular injections of adeno-associated virus serotype 6 (AAV6), a vector capable of axonal retrograde transport, to deliver therapeutic genetic information across the lower MN axis. Neonatal muscle delivery of AAV expressing small hairpin RNAs (shRNAs) against the toxic transgene in this model, human mutant superoxide dismutase 1 (mSOD1), led to significant mSOD1 knockdown in the muscle as well as innervating MNs. This knockdown conferred neuroprotection and halted muscle atrophy in individually targeted MN pools. However, despite the vector being targeted to MNs that innervate muscle groups controlling eating, breathing, and locomotion, this approach was unable to therapeutically impact on disease progression in the ALS mouse model. These results stress the complexity of gene delivery for mSOD1 silencing and suggest that critical thresholds of protein knockdown and transduction across various cell types are required to translate local neuroprotective effects into functional improvements.

A method for removing the brain and spinal cord as one unit from adult mice and rats

To collect complete rodent spinal cord samples for histological analysis, researchers typically use a method that involves fixation of the carcass, followed by decapitation and removal of the vertebrae and the spinal cord. Researchers then decalcify, process and embed the spinal column in paraffin. When this method is used, the spinal cord retains its natural curvature, which may be undesirable to some investigators. The authors describe a methodology by which the entire spinal cord, with the brain attached, can be removed from a mouse or rat, set against a rigid support material and fixed perfectly straight. This allows for more precise sectioning and simplified histological analysis. Researchers can even create block preparations, each of which contains multiple spinal cord sections, so that they can compare anatomically matched sections. This procedure can also be used to obtain fresh spinal cord samples that are free of bone and can be frozen in optimal cutting temperature medium.

Diffusion Tensor Imaging of the Pediatric Spinal Cord at 1.5T: Preliminary Results

Recent studies suggest that pediatric subjects as old as 8-years-of-age may have difficulty with the ISNCSCI examinations. Our aim was to investigate DTI parameters of healthy spinal cord in children with noncervical IS for comparison with children with SCI and to prospectively evaluate reliability measures of DTI and to correlate the measures obtained in children with SCI with the ISNCSCI. Five controls with thoracic and lumbar IS and 5 children with cervical SCI were imaged twice by using a single-shot echo-planar diffusion-weighted sequence. Axial imaging was performed to cover the entire cervical spinal cord in controls. For the SCI subjects, 2 vertebral bodies above and below the injury were imaged. FA and D values were obtained at different levels of the cervical spinal cord. All subjects with SCI had undergone ISNCSCI clinical examinations. Statistical analysis was performed to access differences of the DTI indices between the controls and SCI subjects, reproducibility measurements, and correlations between DTI and ISNCSCI. Subjects with SCI showed reduced FA and increased D values compared with controls. Test-retest reproducibility showed good ICC coefficients in all the DTI index values among controls (≥0.9), while the SCI group showed moderate ICC (≥0.77). There were statistically significant correlations between the various DTI indices and ISNCSCI scores. Preliminary DTI indices in children were determined and showed good reproducibility. Reduced FA and increased D values were seen in children with SCI in comparison with controls and showed good clinical correlation with ISNCSCI examinations.

Distribution of syringomyelia along the entire spinal cord in clinically affected Cavalier King Charles Spaniels

Chiari-like malformation (CM) and syringomyelia (SM) is an important disease complex in the Cavalier King Charles Spaniel (CKCS) but data about the anatomical distribution of SM along the spinal cord are lacking in veterinary medicine. The objective of this study was to define the anatomic distribution of SM in CKCS clinically affected by CM/SM. Magnetic resonance imaging (MRI) of the brain and the entire spinal cord of 49 dogs was performed and different morphological parameters compared. Syrinx formation was present in the C1-C4 region and in other parts of the spinal cord. The maximal dorsoventral syrinx size can occur in any region of the spinal cord and the total syrinx size was positively correlated with age. Seventy-six per cent of CKCS with a cranial cervical syrinx also have a syrinx affecting more caudal spinal cord regions. MRI restricted to the cervical region may underestimate the extent of SM and the severity of the disease process in the majority of dogs.

Intraoperative Electrophysiological Monitoring in Spine Surgery

Review of the literature with analysis of pooled data. To assess common intraoperative neuromonitoring (IOM) changes that occur during the course of spinal surgery, potential causes of change, and determine appropriate responses. Further, there will be discussion of appropriate application of IOM, and medical legal aspects. The structured literature review will answer the following questions: What are the various IOM methods currently available for spinal surgery? What are the sensitivities and specificities of each modality for neural element injury? How are the changes in each modality best interpreted? What is the appropriate response to indicated changes? Recommendations will be made as to the interpretation and appropriate response to IOM changes. Total number of abstracts identified and reviewed was 187. Full review was performed on 18 articles. The MEDLINE database was queried using the search terms IOM, spinal surgery, SSEP, wake-up test, MEP, spontaneous and triggered electromyography alone and in various combinations. Abstracts were identified and reviewed. Individual case reports were excluded. Detailed information and data from appropriate articles were assessed and compiled. Ability to achieve IOM baseline data varied from 70% to 98% for somatosensory-evoked potentials (SSEP) and 66% to 100% for motor-evoked potentials (MEP) in absence of neural axis abnormality. Multimodality intraoperative neuromonitoring (MIOM) provided false negatives in 0% to 0.79% of cases, whereas isolated SSEP monitoring alone provided false negative in 0.063% to 2.7% of cases. MIOM provided false positive warning in 0.6% to 1.38% of cases. As spine surgery, and patient comorbidity, becomes increasingly complex, IOM permits more aggressive deformity correction and tumor resection. Combination of SSEP and MEP monitoring provides assessment of entire spinal cord functionality in real time. Spontaneous and triggered electromyography add assessment of nerve roots. The wake-up test can continue to serve as a supplement when needed. MIOM may prove useful in preservation of neurologic function where an alteration of approach is possible. IOM is a valuable tool for optimization of outcome in complex spinal surgery.