Prognostic Factors in Canine Acute Intervertebral Disc Disease.

Knowledge of the prognosis of acute spinal cord injury is critical to provide appropriate information for clients and make the best treatment choices. Acute intervertebral disc extrusions (IVDE) are a common cause of pain and paralysis in dogs with several types of IVDE occurring. Important prognostic considerations are recovery of ambulation, return of urinary and fecal continence, resolution of pain and, on the negative side, development of progressive myelomalacia. Initial injury severity affects prognosis as does type of IVDE, particularly when considering recovery of continence. Overall, loss of deep pain perception signals a worse outcome. When considering Hansen type 1 IVDE, the prognosis is altered by the choice of surgical vs. medical therapy. Concentration of structural proteins in the plasma, as well as inflammatory mediators, creatine kinase, and myelin basic protein in the cerebrospinal fluid (CSF) can provide additional prognostic information. Finally, cross-sectional area and length of T2 hyperintensity and loss of HASTE signal on MRI have been associated with outcome. Future developments in plasma and imaging biomarkers will assist in accurate prognostication and optimization of patient management.

Diagnostic Imaging in Intervertebral Disc Disease.

Imaging is integral in the diagnosis of canine intervertebral disc disease (IVDD) and in differentiating subtypes of intervertebral disc herniation (IVDH). These include intervertebral disc extrusion (IVDE), intervertebral disc protrusion (IVDP) and more recently recognized forms such as acute non-compressive nucleus pulposus extrusion (ANNPE), hydrated nucleus pulposus extrusion (HNPE), and intradural/intramedullary intervertebral disc extrusion (IIVDE). Many imaging techniques have been described in dogs with roles for survey radiographs, myelography, computed tomography (CT), and magnetic resonance imaging (MRI). Given how common IVDH is in dogs, a thorough understanding of the indications and limitations for each imaging modality to aid in diagnosis, treatment planning and prognosis is essential to successful case management. While radiographs can provide useful information, especially for identifying intervertebral disc degeneration or calcification, there are notable limitations. Myelography addresses some of the constraints of survey radiographs but has largely been supplanted by cross-sectional imaging. Computed tomography with or without myelography and MRI is currently utilized most widely and have become the focus of most contemporary studies on this subject. Novel advanced imaging applications are being explored in dogs but are not yet routinely performed in clinical patients. The following review will provide a comprehensive overview on common imaging modalities reported to aid in the diagnosis of IVDH including IVDE, IVDP, ANNPE, HNPE, and IIVDE. The review focuses primarily on canine IVDH due to its frequency and vast literature as opposed to feline IVDH.

Long-term clinical and magnetic resonance imaging follow-up of dogs with osseous-associated cervical spondylomyelopathy.

BACKGROUND: Osseous-associated cervical spondylomyelopathy (OA-CSM) is a complex disorder with limited long-term survival. The longitudinal progression is currently unknown. OBJECTIVE: To describe changes on magnetic resonance imaging (MRI) over a 2-year minimum period. We hypothesized that spinal lesions would progress in the majority of dogs. ANIMALS: Eleven dogs previously diagnosed with OA-CSM were prospectively studied. Nine dogs were treated medically, whereas 2 were treated surgically. METHODS: Clinical and MRI follow-up were performed with a median time between MRI studies of 30 months (range, 24-54). Morphologic assessment evaluated vertebral canal stenosis, spinal cord compression, foraminal stenosis, and articular processes, among other variables. Morphometric assessment included vertebral canal area, spinal cord area, area of the articular processes, and foraminal height. RESULTS: On follow-up MRI, the most affected site at the initial examination in medically treated dogs had progressed in 4 of 9 dogs, improved in 4, and was unchanged in 3. Clinically, all dogs except 2 medically treated dogs were unchanged to improve at follow-up. Initially, 50 of 60 (83.3%) intervertebral spaces had vertebral canal stenosis, whereas in the follow-up MRI 82.3% did. Of the sites with stenosis, 45.7% were unchanged, 18.6% improved, and 38.9% worsened. Morphometry identified significant decreases in vertebral canal and spinal cord areas at C4-C5 through C6-C7, and significant progression of articular process irregularities at C3-C4 and C6-C7. CONCLUSIONS AND CLINICAL IMPORTANCE: This long-term follow-up study of dogs with OA-CSM did not identify clinical or MRI progression of lesions in the majority of dogs.

Neurologic and magnetic resonance imaging features of German Shepherd Dogs with cervical spondylomyelopathy: 10 cases (2006-2018).

OBJECTIVE: To describe the neurologic signs and MRI findings for German Shepherd Dogs (GSDs) with cervical spondylomyelopathy (CSM). ANIMALS: 10 GSDs with confirmed CSM. PROCEDURES: Medical records from January 2006 through July 2018 were reviewed to identify dogs with CSM. For each CSM-affected dog, information regarding age, duration of clinical signs, presence of neurologic signs, and treatments administered were obtained; the main site and cause of spinal cord compression and other vertebral and spinal cord changes were identified on MRI images. RESULTS: Data for 9 male and 1 female (mean age, 6.2 years) GSDs with CSM were assessed. Dogs were classified as having chronic (n = 9) or acute (1) CSM. Nine dogs had ataxia; 1 dog had only signs of cervical hyperesthesia. Neurologic examination findings localized the lesion to the cervical portion of the vertebral column in each dog. The main spinal cord compression site was at the C6-7 (n = 5), C5-6 (4), or C4-5 (1) intervertebral spaces; osseous proliferation of the articular processes was the sole or a contributory cause of these compressions for 6 of the 10 dogs. Eight dogs also had dorsal compression of the spinal cord as the result of ligamenta flava hypertrophy. CONCLUSIONS AND CLINICAL RELEVANCE: The 10 GSDs of the present retrospective case series had CSM that was often characterized by osseous changes and a ligamentous component and were older than dogs of other breeds (eg, Great Dane and Mastiff) with osseous-associated CSM described in previous reports. Cervical spondylomyelopathy should be a differential diagnosis for GSDs with ataxia, paresis, or signs of cervical hyperesthesia.

MicroRNA expression in the cerebrospinal fluid of dogs with and without cervical spondylomyelopathy.

BACKGROUND: Osseous-associated cervical spondylomyelopathy (OA-CSM) is a common condition of the cervical vertebral column that affects giant dog breeds. MicroRNAs (miRNAs) are small RNAs that regulate gene expression, and recent data suggest that circulating miRNAs present in biological fluids may serve as potential biomarkers for disease. The miRNA profiles of cerebrospinal fluid (CSF) from healthy dogs and dogs clinically affected by OA-CSM have not been described. OBJECTIVE: To characterize the expression levels of miRNAs present in the CSF of normal Great Danes and identify differentially expressed miRNAs in the CSF of Great Danes clinically affected with OA-CSM. ANIMALS: Client-owned dogs: 12 control, 12 OA-CSM affected. METHODS: Cerebrospinal fluid samples were collected prospectively. MicroRNA expression was evaluated using the NanoString nCounter platform and quantitative real-time PCR. RESULTS: We identified 8 miRNAs with significant differential expression. MiR-299-5p and miR-765 had increased expression levels in the CSF of OA-CSM-affected dogs, whereas miR-494, miR-612, miR-302-d, miR-4531, miR-4455, and miR-6721-5p had decreased expression levels in OA-CSM affected dogs compared to clinically normal dogs. Quantitative real-time PCR was performed to validate the expression levels of 2 miRNAs (miR-494 and miR-612), and we found a 1.5-fold increase in miR-494 expression and a 1.2-fold decrease in miR-612 in the CSF of the OA-CSM affected group (P = .41 and .89, respectively). CONCLUSIONS AND CLINICAL IMPORTANCE: Data generated from our study represent an initial characterization of the miRNA profile of normal canine CSF and suggest that a distinct CSF miRNA expression profile is associated with OA-CSM.

Clinical and magnetic resonance imaging characterization of cervical spondylomyelopathy in juvenile dogs.

BACKGROUND: Cervical spondylomyelopathy (CSM) occurs because of compression of the cervical spinal cord, nerve roots, or both, usually affecting young adult to older large and giant breed dogs. Juvenile dogs are affected infrequently. OBJECTIVE: To describe clinical and magnetic resonance imaging (MRI) findings in juvenile dogs (≤ 12 months) with cervical spondylomyelopathy. ANIMALS: Twenty CSM-affected juvenile dogs. METHODS: Medical and imaging records for juvenile dogs with CSM were reviewed. History and neurologic examination findings were obtained, including follow-up data. The MRI studies were reviewed for cause and site of spinal cord compression, intervertebral disk protrusion or degeneration, articular process degenerative changes, intervertebral foraminal stenosis, and spinal cord signal changes. RESULTS: Mean (median) age at the time of diagnosis was 9.4 (10) months. There were 16 giant breed dogs. Eighteen dogs had a chronic presentation, 18/20 had proprioceptive ataxia, and 9/20 had cervical pain. On MRI, the principal spinal cord compression occurred at C5-C6, C6-C7, or both in most dogs; 12/20 dogs had ≥2 sites of spinal cord compression. The cause of compression was articular process proliferation in 8/20 dogs and disk protrusion in 2/20 dogs. Intervertebral disk degeneration was seen in 9/20 dogs. Follow-up was obtained for 12/20 dogs: 10/12 were managed medically and 2/12 surgically. CONCLUSIONS AND CLINICAL IMPORTANCE: Cervical spondylomyelopathy in juvenile dogs was characterized mostly by osseous-associated spinal cord compression and multiple compressive sites. Almost half of the dogs had intervertebral disk degeneration. Intervertebral disk protrusion was seen in both giant and large breed dogs.

Long-term computed tomography follow-up in great Danes with or without signs of osseous- associated cervical Spondylomyelopathy.

BACKGROUND: Osseous- associated cervical spondylomyelopathy (OA-CSM) has a high prevalence in Great Danes. In order to understand the progression of osseous changes, we aimed to perform a long-term computed tomographic (CT) follow-up study of Great Dane dogs with and without OA-CSM. Canine CSM is comparable to a common neurologic disease often diagnosed in older people termed cervical spondylotic myelopathy or degenerative cervical myelopathy, which is progressive in nature. The natural history of cervical spondylotic myelopathy in people has been well described, whereas there is scarce information on the natural history of canine OA-CSM. Our first goal was to evaluate if follow-up CT studies showed any changes compared to initial CT studies in Great Dane dogs with a diagnosis of OA-CSM. Our second goal was to establish whether clinically normal Great Danes went on to develop any vertebral changes or clinical signs consistent with OA-CSM. We enrolled Great Danes diagnosed with OA-CSM and clinically normal Great Danes who had previously participated in a prospective study. All dogs had clinical and CT follow-up evaluations. RESULTS: Twelve Great Dane dogs were investigated: six OA-CSM affected and six clinically normal dogs. The median time between CT studies was 28 months (OA-CSM dogs) and 25 months (normal dogs). On follow-up CT, two OA-CSM-affected dogs developed new sites of stenosis, and two clinically normal dogs developed new sites of stenosis (one each). Disc spaces most commonly affected were C4-C5, C5-C6 and C6-C7. New sites of foraminal stenosis were noted in two of the CSM-affected and four of the clinically normal dogs. Morphometric evaluation showed no statistically significant differences between the initial and follow-up CT studies in the OA-CSM affected or normal groups. CONCLUSION: Our long-term CT follow-up study documented progression of vertebral canal stenosis in four out of twelve dogs. The majority of dogs did not develop new sites of stenosis or show progression of vertebral lesions.

Clinical features and short-term outcome of presumptive intracranial complications associated with otitis media/interna: a multi-center retrospective study of 19 cats (2009-2017).

OBJECTIVES: The aim of this study was to compile an overview of the clinical features of intracranial complication of otitis media/interna (OMI) in cats managed across five veterinary referral hospitals. Of additional interest were culture results that could inform empirical antibiotic selection, as well as outcome with both medical and surgical management. METHODS: A retrospective medical record review was conducted at five veterinary referral practices to identify cats with a diagnosis of intracranial complication secondary to OMI between 2009 and 2017. Clinical features, diagnostic findings, treatment and outcome were recorded. RESULTS: At total of 19 cats were identified. Sixty-three percent had no previous history of ear infection. Otoscopic examination was normal in 47% of cases. The most common bacterial isolate was Pasteurella multocida, which was identified in 24% of cases. Outcome was successful for 83% of cats managed with ventral bulla osteotomy (VBO) and in 66% of cats managed without surgical intervention. CONCLUSIONS AND RELEVANCE: Clinical suspicion of intracranial complications of OMI should remain high in cats with central vestibular disease even if otoscopic examination is normal. Antibiotic selection should be based on a culture and sensitivity; however, initial antibiotic therapy should include broad-spectrum coverage with special consideration for P multocida. Cats with intracranial complications of OMI can have a good outcome with either surgical or medical management and prospective studies are needed to assess the role of VBO in enhancing recovery.

Pharmacokinetics of Riluzole in Beagle Dogs.

BACKGROUND: Riluzole is a benzothiazole anticonvulsant used in the treatment of patients with amyotrophic lateral sclerosis and it is being investigated for clinical use in patients with spinal cord injury. The present study evaluated the pharmacokinetics of riluzole in beagle dogs after oral dose administration. METHODS: The oral doses (1.5, 5, 15 and 50 mg/kg) of riluzole were administered to beagle dogs and blood samples were collected from 0 h to 24 h post drug administration. Riluzole was quantified by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). RESULTS: The method was sensitive, precise, accurate and selective to riluzole quantification in plasma of beagle dogs. The pharmacokinetics following oral administration was linear from 1.5 to 15 mg/kg and the t1/2 was 2.16, 1.5, 1.8 and 3.0 h after oral administration of 1.5, 5.0, 15 and 50 mg/kg riluzole. CONCLUSION: The riluzole pharmacokinetics was linear up to 15 mg/kg and had a significantlyshorter t1/2 in beagle dogs than in humans.

Development of an International Canine Spinal Cord Injury observational registry: a collaborative data-sharing network to optimize translational studies of SCI.

STUDY DESIGN: Prospective cross-sectional cohort study. OBJECTIVES: The canine spontaneous model of spinal cord injury (SCI) is as an important pre-clinical platform as it recapitulates key facets of human injury in a naturally occurring context. The establishment of an observational canine SCI registry constitutes a key step in performing epidemiologic studies and assessing the impact of therapeutic strategies to enhance translational research. Further, accumulating information on dogs with SCI may contribute to current "big data" approaches to enhance understanding of the disease using heterogeneous multi-institutional, multi-species datasets from both pre-clinical and human studies. SETTING: Multiple veterinary academic institutions across the United States and Europe. METHODS: Common data elements recommended for experimental and human SCI studies were reviewed and adapted for use in a web-based registry, to which all dogs presenting to member veterinary tertiary care facilities were prospectively entered over ~1 year. RESULTS: Analysis of data accumulated during the first year of the registry suggests that 16% of dogs with SCI present with severe, sensorimotor-complete injury and that 15% of cases are seen by a tertiary care facility within 8 h of injury. Similar to the human SCI population, 34% were either overweight or obese. CONCLUSIONS: Severity of injury and timing of presentation suggests that neuroprotective studies using the canine clinical model could be conducted efficiently using a multi-institutional approach. Additionally, pet dogs with SCI experience similar comorbidities to people with SCI, in particular obesity, and could serve as an important model to evaluate the effects of this condition.

Kinetic and kinematic follow-up gait analysis in Doberman Pinschers with cervical spondylomyelopathy treated medically and surgically.

BACKGROUND: The efficacy of treatment of dogs with cervical spondylomyelopathy (CSM) is commonly based on the owner's and clinician's perception of the gait, which is highly subjective and suffers from observer bias. HYPOTHESIS/OBJECTIVES: To compare selected kinetic and kinematic parameters before and after treatments and to correlate the findings of gait analysis to clinical outcome. ANIMALS: Eight Doberman Pinschers with CSM confirmed by magnetic resonsance imaging. METHODS: Patients were prospectively studied and treated with either medical management (n = 5) or surgery (n = 3). Force plate analysis and 3-D kinematic motion capture were performed at initial presentation and approximately 8 weeks later. Force plate parameters evaluated included peak vertical force (PVF). Kinematic parameters measured included number of pelvic limb strides, stifle flexion and extension, maximum and minimum thoracic limb distance, truncal sway, and thoracic limb stride duration. RESULTS: Kinematic analysis showed that deviation of the spine to the right (truncal sway) was significantly smaller (P < .001) and the degree of right stifle flexion was significantly larger (P = .029) after treatment. Force plate analysis indicated that PVF was significantly different after treatment (P = .049) and the difference of the PVF also was significantly larger (P = .027). However, no correlation was found with either method of gait analysis and clinical recovery. CONCLUSIONS AND CLINICAL IMPORTANCE: Kinetic and kinematic gait analysis were able to detect differences in dogs with CSM before and after treatment. A correlation of gait analysis to clinical improvement could not be determined.

Comparison of the percentage of the C3-C7 vertebral canal occupied by the spinal cord in small-breed dogs with that in Doberman Pinschers and Great Danes with and without cervical spondylomyelopathy.

OBJECTIVE To compare the percentage of the C3-C7 vertebral canal occupied by the spinal cord in small-breed dogs with that in Doberman Pinschers and Great Danes with and without cervical spondylomyelopathy (CSM). ANIMALS 30 small-breed dogs (body weight, < 15 kg), 15 clinically normal Doberman Pinschers, 15 Doberman Pinschers with CSM, 15 clinically normal Great Danes, and 15 Great Danes with CSM. PROCEDURES In a retrospective study, sagittal and transverse T2-weighted MRI images of the cervical (C3 to C7) vertebral column obtained from dogs that met study criteria and were free of extensive abnormalities that could affect the spinal cord diameter between January 2005 and February 2015 were reviewed. The area and height of the vertebral column and spinal cord were measured at the cranial and caudal aspect of each vertebra from C3 to C7, and the percentage of the vertebral canal occupied by the spinal cord at each location was calculated and compared among groups of dogs. RESULTS Mean percentage of the vertebral canal occupied by the spinal cord was greatest for small-breed dogs and lowest for Great Danes, but did not differ between Doberman Pinschers and small-breed dogs at approximately half of the locations evaluated or between Doberman Pinschers with and without CSM or between Great Danes with and without CSM. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the percentage of the vertebral canal occupied by the spinal cord, although expected to increase with vertebral canal stenosis, may not have a primary role in the pathogenesis of CSM.

Evaluation of osseous-associated cervical spondylomyelopathy in dogs using kinematic magnetic resonance imaging.

Osseous-associated cervical spondylomyelopathy in dogs is characterized by both static and dynamic spinal cord compression; however, standard MRI methods only assess static compression. In humans with cervical spondylotic myelopathy, kinematic MRI is commonly used to diagnose dynamic spinal cord compressions. The purpose of this prospective, analytical study was to evaluate kinematic MRI as a method for characterizing the dynamic component of osseous-associated cervical spondylomyelopathy in dogs. We hypothesized that kinematic MRI would allow visualization of spinal cord compressions that were not identified with standard imaging. Twelve client-owned dogs with osseous-associated cervical spondylomyelopathy were enrolled. After standard MRI confirmed a diagnosis of osseous-associated cervical spondylomyelopathy, a positioning device was used to perform additional MRI sequences with the cervical vertebral column flexed and extended. Morphologic and morphometric (spinal cord height, intervertebral disc width, spinal cord width, vertebral canal height, and spinal cord area) assessments were recorded for images acquired with neutral, flexion, and extension imaging. A total of 25 compressions were seen with neutral positioning, while extension identified 32 compressions. There was a significant association between extension positioning and presence of a compressive lesion at C4-C5 (p = 0.02). Extension was also associated with a change in the most severe site of compression in four out of 12 (33%) dogs. None of the patients deteriorated neurologically after kinematic imaging. We concluded that kinematic MRI is a feasible method for evaluating dogs with osseous-associated cervical spondylomyelopathy, and can reveal new compressions not seen with neutral positioning.

Targeting Translational Successes through CANSORT-SCI: Using Pet Dogs To Identify Effective Treatments for Spinal Cord Injury.

Translation of therapeutic interventions for spinal cord injury (SCI) from laboratory to clinic has been historically challenging, highlighting the need for robust models of injury that more closely mirror the human condition. The high prevalence of acute, naturally occurring SCI in pet dogs provides a unique opportunity to evaluate expeditiously promising interventions in a population of animals that receive diagnoses and treatment clinically in a manner similar to persons with SCI, while adhering to National Institutes of Health guidelines for scientific rigor and transparent reporting. In addition, pet dogs with chronic paralysis are often maintained long-term by their owners, offering a similarly unique population for study of chronic SCI. Despite this, only a small number of studies have used the clinical dog model of SCI. The Canine Spinal Cord Injury Consortium (CANSORT-SCI) was recently established by a group of veterinarians and basic science researchers to promote the value of the canine clinical model of SCI. The CANSORT-SCI group held an inaugural meeting November 20 and 21, 2015 to evaluate opportunities and challenges to the use of pet dogs in SCI research. Key challenges identified included lack of familiarity with the model among nonveterinary scientists and questions about how and where in the translational process the canine clinical model would be most valuable. In light of these, we review the natural history, outcome, and available assessment tools associated with canine clinical SCI with emphasis on their relevance to human SCI and the translational process.

Adaptation of the Basso-Beattie-Bresnahan locomotor rating scale for use in a clinical model of spinal cord injury in dogs.

BACKGROUND: Naturally occurring acute spinal cord injury (SCI) in pet dogs provides an important clinical animal model through which to confirm and extend findings from rodent studies; however, validated quantitative outcome measures for dogs are limited. NEW METHOD: We adapted the Basso Beattie Bresnahan (BBB) scale for use in a clinical dog model of acute thoracolumbar SCI. Based on observation of normal dogs, modifications were made to account for species differences in locomotion. Assessments of paw and tail position, and trunk stability were modified to produce a 19 point scale suitable for use in dogs, termed the canine BBB scale (cBBB). Pet dogs with naturally occurring acute SCI were assigned cBBB scores at 3, 10 and 30days after laminectomy. RESULTS: Scores assigned via the cBBB were stable across testing sessions in normal dogs but increased significantly between days 3 and 30 in SCI-affected dogs (p=0.0003). The scale was highly responsive to changes in locomotor recovery over a 30day period, with a standardized response mean of 1.34. COMPARISON WITH EXISTING METHODS: Concurrent validity was good, with strong correlations observed between the cBBB and two other locomotor scales, the OSCIS (r=0.94; p<0.001) and the MFS (r=0.85; p<0.0001). cBBB scores inversely correlated with other assessments of recovery including mechanical sensory threshold (r=-0.68; p<0.0001) and coefficient of variation of stride length (r=-0.49; p<0.0001). CONCLUSIONS: These results support the use of the cBBB to assess locomotor recovery in canine clinical translational models of SCI.

Cystic Abnormalities of the Spinal Cord and Vertebral Column.

Cystic lesions of the vertebral column and spinal cord are important differential diagnoses in dogs with signs of spinal cord disease. Synovial cysts are commonly associated with degenerative joint disease and usually affect the cervical and lumbosacral regions. Arachnoid diverticulum (previously known as cyst) is seen in the cervical region of large breed dogs and thoracolumbar region of small breed dogs. This article reviews the causes, diagnosis, and treatment of these and other, less common, cystic lesions.

Temporospatial and kinetic gait variables of Doberman Pinschers with and without cervical spondylomyelopathy.

OBJECTIVE: To characterize and compare gait variables in Doberman Pinschers with and without cervical spondylomyelopathy (CSM). ANIMALS: 18 Doberman Pinschers (9 clinically normal dogs and 9 CSM-affected dogs). PROCEDURES: A neurologic examination was performed on all dogs. The diagnosis of CSM was confirmed with MRI. Temporospatial and kinetic gait variables were measured by use of a pressure-sensitive walkway. Temporospatial variables evaluated included stance phase duration, swing phase duration, gait cycle duration, stride length, and gait velocity. Kinetic variables evaluated included peak vertical force and vertical impulse. Random-effects linear regression was used to determine the difference between CSM-affected and clinically normal dogs for each of the 7 variables. RESULTS: Values for temporospatial variables were significantly smaller in the thoracic limbs of CSM-affected dogs, compared with values for the thoracic limbs of clinically normal dogs. For the kinetic variables, peak vertical force was significantly higher in the thoracic limbs than the pelvic limbs for all dogs. Vertical impulse values were higher in the thoracic limbs than the pelvic limbs. There were significant differences in mean vertical impulse between the thoracic and pelvic limbs for both groups. CONCLUSIONS AND CLINICAL RELEVANCE: In this study, significant differences in temporospatial variables were identified between the thoracic limbs of clinically normal and CSM-affected dogs, with the values being smaller for the CSM-affected dogs than for the clinically normal dogs. A pressure-sensitive walkway may provide a valid, practical option for rapid, objective assessment of gait and response to treatment in dogs with CSM.

Morphological changes of the caudal cervical intervertebral foramina due to flexion-extension and compression-traction movements in the canine cervical vertebral column.

BACKGROUND: Previous studies in humans have reported that the dimensions of the intervertebral foramina change significantly with movement of the spine. Cervical spondylomyelopathy (CSM) in dogs is characterized by dynamic and static compressions of the neural components, leading to variable degrees of neurologic deficits and neck pain. Studies suggest that intervertebral foraminal stenosis has implications in the pathogenesis of CSM. The dimensions of the cervical intervertebral foramina may significantly change during neck movements. This could have implication in the pathogenesis of CSM and other diseases associated with radiculopathy such as intervertebral disc disease. The purpose of this study was to quantify the morphological changes in the intervertebral foramina of dogs during flexion, extension, traction, and compression of the canine cervical vertebral column. All vertebral columns were examined with magnetic resonance imaging prior to biomechanic testing. Eight normal vertebral columns were placed in Group 1 and eight vertebral columns with intervertebral disc degeneration or/and protrusion were assigned to Group 2. Molds of the left and right intervertebral foramina from C4-5, C5-6 and C6-7 were taken during all positions and loading modes. Molds were frozen and vertical (height) and horizontal (width) dimensions of the foramina were measured. Comparisons were made between neutral to flexion and extension, flexion to extension, and traction to compression in neutral position. RESULTS: Extension decreased all the foraminal dimensions significantly, whereas flexion increased all the foraminal dimensions significantly. Compression decreased all the foraminal dimensions significantly, and traction increased the foraminal height, but did not significantly change the foraminal width. No differences in measurements were seen between groups. CONCLUSIONS: Our results show movement-related changes in the dimensions of the intervertebral foramina, with significant foraminal narrowing in extension and compression.

Proteomic analysis of cerebrospinal fluid in canine cervical spondylomyelopathy.

STUDY DESIGN: Prospective study. OBJECTIVE: To identify proteins with differential expression in the cerebrospinal fluid (CSF) from 15 clinically normal (control) dogs and 15 dogs with cervical spondylomyelopathy (CSM). SUMMARY OF BACKGROUND DATA: Canine CSM is a spontaneous, chronic, compressive cervical myelopathy similar to human cervical spondylotic myelopathy. There is a limited knowledge of the molecular mechanisms underlying these conditions. Differentially expressed CSF proteins may contribute with novel information about the disease pathogenesis in both dogs and humans. METHODS: Protein separation was performed with 2-dimensional electrophoresis. A Student t test was used to detect significant differences between groups (P < 0.05). Three comparisons were made: (1) control versus CSM-affected dogs, (2) control versus non-corticosteroid-treated CSM-affected dogs, and (3) non-corticosteroid-treated CSM-affected versus corticosteroid-treated CSM-affected dogs. Protein spots exhibiting at least a statistically significant 1.25-fold change between groups were selected for subsequent identification with capillary-liquid chromatography tandem mass spectrometry. RESULTS: A total of 96 spots had a significant average change of at least 1.25-fold in 1 of the 3 comparisons. Compared with the CSF of control dogs, CSM-affected dogs demonstrated increased CSF expression of 8 proteins including vitamin D-binding protein, gelsolin, creatine kinase B-type, angiotensinogen, α-2-HS-glycoprotein, SPARC (secreted protein, acidic, rich in cysteine), calsyntenin-1, and complement C3, and decreased expression of pigment epithelium-derived factor, prostaglandin-H2 D-isomerase, apolipoprotein E, and clusterin. In the CSF of CSM-affected dogs, corticosteroid treatment increased the expression of haptoglobin, transthyretin isoform 2, cystatin C-like, apolipoprotein E, and clusterin, and decreased the expression of angiotensinogen, α-2-HS-glycoprotein, and gelsolin. CONCLUSION: Many of the differentially expressed proteins are associated with damaged neural tissue, bone turnover, and/or compromised blood-spinal cord barrier. The knowledge of the protein changes that occur in CSM and upon corticosteroid treatment of CSM-affected patients will aid in further understanding the pathomechanisms underlying this disease. LEVEL OF EVIDENCE: N/A.