Dorsal laminectomy for the treatment of lateralised cervical intervertebral disc extrusions in dogs-Prognosis and complications

Objective

Describe the complication rate, expected hospitalization time and prognosis associated with dorsal laminectomy for the treatment of lateralised cervical intervertebral disc extrusion (IVDE) in dogs.

Methods

This is a single-center retrospective case series study. Databases were reviewed from 2012 to 2022 for dogs that had a dorsal laminectomy to treat a lateralised cervical IVDE. Dogs were excluded if additional surgical techniques were performed, or other comorbidities were found on MRI.

Results

Fifty two dogs were included the study. French bulldogs represented 28.8% of the cohort. Patient median age was 6 years and median weight 15 kg. Thirty-five dogs (67.3%) presented clinical signs for <3 days and almost half (44.2%) were ambulatory but presented cervical pain and neurological deficits. Median surgical time was 85 min. Minor intraoperative complications were reported in 22 (42.3%), with hypothermia being the most common. Thirteen (25%) needed revision surgery due to persistent cervical pain with (9/13) or without (4/13) neurological deficits. Re-extrusion or persistent extrusion was found in 92.3% of cases needing surgical revision. Median hospitalization time was 6 days. Forty-seven (90.4%) cases had a good outcome.

Conclusions and clinical significance

Despite the relatively high rate of intraoperative complications and cases needing revision surgery, dorsal laminectomy as surgical treatment for lateralised cervical IVDE is still associated with good long-term prognosis in most of cases. Prognosis is good even when revision surgery is necessary but expected hospitalization time seems to be higher when compared to an alternative surgical technique.

Treatment of Canine Disc-Associated Cervical Spondylomyelopathy with a Cervical Distraction-Stabilization Technique (C-LOX Combined with LCP Plate) and Clinical Outcomes

Canine disc-associated cervical spondylomyelopathy (DA-CSM) is a form of caudal CSM, characterized by the compression of the spinal cord and nerve roots due to an intervertebral disc protrusion. It is more frequent in large canine breeds. A variety of surgical techniques has been proposed for DA-CSM. The aim of the study was to evaluate the outcomes of a cervical distraction-stabilization technique using an intervertebral anchored fusion device (C-LOX) combined with a locking compression plate (LCP plate) for the treatment of DA-CSM in dogs, based on clinical and radiographical follow-up data. Thirteen dogs affected by DA-CSM were included in the study. After the surgical procedure, an improvement in neurological status was documented in 9/13 cases. This cervical distraction-stabilization technique seems to be a valuable surgical alternative to treat this canine pathology.

Magnetic resonance imaging and neurologic characterization of combined osseous- and disc-associated cervical spondylomyelopathy in dogs

BACKGROUND

Although both disc- or osseous-associated forms of cervical spondylomyelopathy (CSM) are observed in the same dogs, this combined form has not been thoroughly evaluated.

OBJECTIVES

To describe imaging characteristics of dogs with concurrent disc- and osseous CSM and investigate an association between findings on neurological examination and imaging.

ANIMALS

Sixty dogs with disc and osseous-associated CSM from 232 CSM-affected dogs.

METHODS

Retrospective study. Dogs diagnosed via high-field MRI with a combination of intervertebral disc (IVD) protrusion and osseous proliferation of articular processes, dorsal lamina, or both were identified. Large and giant breed dogs were grouped according to whether combined compressions were at the same site or different sites. Statistical methods were used to investigate the association and relationship between variables.

RESULTS

Thirty-five out of 60 (58%) were large breeds and 22/60 (37%) were giant breeds. Mean and median age was 6.6 and 7 years respectively (range, 0.75-11 years). Forty of the 60 dogs (67%) had concurrent osseous and disc-associated spinal cord compression in the same location. This was considered the main compression site in 32/40 (80%) dogs. Dogs with osseous- and disc-associated compressions at the same site were more likely to have a higher neurologic grade (P = .04).

CONCLUSIONS AND CLINICAL IMPORTANCE

A substantial percentage of dogs with CSM present with concomitant IVD protrusion and osseous proliferations, most at the same site. Characterizing this combined form is important in the management of dogs with CSM because it could affect treatment choices.

Microendoscopic Dorsal Laminectomy for Multi-Level Cervical Intervertebral Disc Protrusions in Dogs

The objective of this study was to evaluate the feasibility and clinical outcomes of microendoscopic dorsal laminectomy for multi-level cervical intervertebral disc protrusions in dogs. Eight client-owned dogs diagnosed with multi-level cervical intervertebral disc protrusions using computed tomography (CT) and magnetic resonance imaging (MRI) were included in this retrospective case series. Microendoscopic dorsal laminectomies (MEL) were performed with an integrated endoscopic system to the cranial and caudal vertebrae of the affected intervertebral joints. Pre- and post-operative neurological status, operation time, intra-operative complications, and postoperative complications were reviewed. Post-operative CT images were obtained to measure the dimensions of laminectomy and compared to those of planned laminectomy. Full endoscopic procedures were feasible in 7 dogs (87.5%) and the laminectomy dimensions were in agreement with pre-operative planning. In all dogs, major intra- and postoperative complications did not occur. Conversion to open surgery was required in one case. Short-term postoperative clinical deterioration was found in two dogs. Long-term clinical outcomes were good and comparable to those reported in previous studies of open dorsal laminectomies. MEL is a promising minimally invasive approach to multi-level cervical dorsal laminectomy for intervertebral disc protrusions. This technique may improve postoperative discomfort compared to the open approach. Further studies are needed to directly compare outcomes between these two approaches.

Comparing the clinical presentation and outcomes of dogs receiving medical or surgical treatment for osseous-associated cervical spondylomyelopathy

BACKGROUND

This study aimed to compare the clinical presentation, short and long term outcomes of dogs treated surgically or medically for Osseous associated cervical spondylomyelopathy.

METHODS

Information collected retrospectively from medical records included signalment, neurological status and treatment type. Surgical treatment consisted of dorsal laminectomy. Medical treatment involved restricted exercise and medication. Improvement or deterioration in neurological status was determined at discharge, re-examination 4-8 weeks post-treatment and by telephone interview with the referring veterinary surgeon or owner at the time of the study, which ranged from 8-54 months following the discharge (median, 16 months).

RESULTS

Twenty-four dogs were treated surgically and 30 medically. Neurological grade at clinical presentation was significantly higher in surgically treated dogs (p = 0.004). Transient early postoperative neurological deterioration occurred in 73.1% of surgically treated dogs. For medical cases, long term improvement was seen in 15% of cases, remained static in 40% and deterioration in 45%. Surgical treatment resulted in long term improvement in 67% of cases, remained static in 29% and deterioration in 4% of cases.

CONCLUSION

This study suggests that surgery is a favourable treatment option, however, requires intensive post-operative care. Medical treatment was associated with a guarded prognosis but could be a viable treatment option for selected dogs.

Association of neurologic signs with high-field MRI findings in 100 dogs with osseous-associated cervical spondylomyelopathy

Although osseous-associated cervical spondylomyelopathy (OA-CSM) findings have been well described using magnetic resonance imaging (MRI), there are no large-scale published studies on the associations between dog size, age, high-field MRI and neurologic findings. Using a retrospective, observational study design, we aimed to investigate an association between neurologic and high-field MRI characteristics in OA-CSM. Records were reviewed for dogs diagnosed with OA-CSM using high-field MRI. One-hundred dogs were included: 73/100 (73%) were giant breeds, 27/100 (27%) large breeds. Mean and median ages were, respectively, 3.1 and 2 years (0.3-9.75 years), with 2.6 and 2 years for giant-breed; and 4.4 and 4 years for large-breed dogs. The majority of dogs were male (75%) with chronic presentation (89%), more than one site of spinal cord compression (78%) and foraminal stenosis (91%). Dogs with multiples sites of spinal cord compression were more likely to have severe spinal cord compression (p < 0.001), severe foraminal stenosis (p < 0.001) and ligamentum flavum/soft tissue proliferation (p = 0.03) than those with a single compressive site. There was a weak correlation between neurologic grade and severity of spinal cord compression (r = 0.27; p = 0.007), number of affected sites (r = 0.24; p = 0.0183) and spinal cord T2W hyperintensity (r = 0.24; p = 0.0152). Intervertebral disc degeneration was seen in 80% of dogs. Age did not appear to have a prominent role in the manifestation of OA-CSM. This study showed that OA-CSM affects a sizeable proportion of young large-breed, in addition to giant-breed dogs.

Magnetic resonance imaging and neurological findings in dogs with disc-associated cervical spondylomyelopathy: a case series

Background

Canine cervical spondylomyelopathy can be separated into osseous and disc-associated (DA-CSM) forms. Our aim was to describe the magnetic resonance imaging (using a high-field scanner) and neurological findings in dogs with DA-CSM and investigate a relationship between these findings.

Results

Sixty-three dogs were included: 60/63 (95 %) were large breeds, with Doberman Pinschers and males over-represented (70 %). Mean and median age at the time of diagnosis was 7.25 and 7.2 years (range 0.41–12 years). Chronic signs were noted in 52/63 (83 %) dogs, with proprioceptive ataxia the most common. Main site of spinal cord compression was commonly C6-7 or C5-6. Thirty-six (57 %) dogs had various sites of spinal cord compression. Most dogs younger than 6 years of age had a single affected site. Foraminal stenosis was present in 51/63 dogs (81 %). T2-weighted hyperintensity was present in 40/63 dogs (63 %). 88 % of the articular processes showed degenerative changes, which correlated strongly with intervertebral disc degeneration. Ligamentum flavum hypertrophy was seen in 38 % of dogs. No correlation was observed between neurologic signs and number of affected sites. A moderate positive correlation was observed between severity of spinal cord compression and neurologic grade (r 0.48; p < 0.001).

Conclusions

DA-CSM was predominantly observed in older, male Dobermans, with lesions located in the caudal cervical vertebral region. It was also seen in dogs 3 years of age or even younger (8 %). Single compressive lesions were more common in dogs younger than 6 years of age. Many dogs had concomitant changes (e.g.: ligamentum flavum hypertrophy and foraminal stenosis). Most dogs with ligamentum flavum hypertrophy were 6 years or older. A positive correlation was observed between severity of spinal cord compression and neurologic grade, but multilevel compression was not associated with more severe neurologic signs. A very high percentage of dogs had articular process degenerative changes. Possible biomechanical or genetic relationships between degenerative changes in articular processes, ligamentum flavum, and intervertebral discs warrants further investigation.

Clinical reasoning in canine cervical hyperaesthesia: which presenting features are important?

BACKGROUND

To evaluate whether clinical features from the history, presentation, physical and neurological examination of dogs with cervical hyperaesthesia are statistically predictive of the underlying diagnosis.

METHODS

Two hundred and ninety-eight dogs presenting with cervical hyperaesthesia between January 2010 and October 2018 were investigated. Only neurologically normal dogs with cervical hyperaesthesia on examination were included, while those with concurrent neurological deficits including gait abnormalities and proprioceptive deficits were excluded. Univariate analysis of clinical variables was performed, and those associated with each diagnosis were retained for multivariable binary logistic regression models.

RESULTS

Ninety-five per cent of cervical hyperaesthesia presentations were represented by eight conditions that included steroid-responsive meningitis arteritis (SRMA; n=100), intervertebral disc extrusion (n=78), syringomyelia (SM; n=51), intervertebral disc protrusion (n=30), neoplasia (n=8), cervical spondylomyelopathy (n=7), immune-mediated polyarthritis (n=5) and meningoencephalomyelitis of unknown aetiology (n=5). Younger age (P=0.003), pyrexia (P=0.003) and haematology abnormalities (P=0.03) comprising leucocytosis, neutrophilia or monocytosis were associated with a diagnosis of SRMA.

CONCLUSIONS

Easy-to-recognise clinical features can be used to identify the most likely differential diagnosis in neurologically normal dogs with cervical hyperaesthesia, which may aid the decision making of veterinary surgeons evaluating dogs with this presentation.

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.

Ventral distraction-stabilization in 5 continuous sites for the treatment of cervical spondylomyelopathy in a Great Dane

OBJECTIVE

To report the combined use of novel and commercially available implants for ventral distraction-stabilization of 5 continuous compressive sites in a Great Dane with cervical spondylomyelopathy (CSM).

STUDY DESIGN

Case report.

ANIMALS

One 4-year-old male Great Dane weighing 78 kg.

METHODS

A tetraparetic 4-year-old Great Dane with osseous-associated CSM (OA-CSM) with 5 sites of dorsolateral compression was presented for surgical intervention. Custom designed Fitz intervertebral traction screws (FITS) and a commercially available polyaxial spinal system were used for ventral distraction-stabilization of all lesions. Multiple neurological reevaluations were performed, with the final evaluation at 27 months postoperatively. Preoperative, immediate-postoperative, and 27 month-postoperative computed tomography (CT) images were retrospectively reviewed to compare the vertebral canal dimensions at the affected sites.

RESULTS

Multilevel distraction-stabilization technique resulted in improvement of the dog's neurological function by 10 days postoperatively. The vertebral canal measurements were revealed to have improved in over half of the measured variables when the 27-month-postoperative images were compared with the preoperative CT images. Increased vertebral canal dimensions were observed immediately after surgery, and some of these measurements continued to improve by 27 months postoperatively.

CONCLUSION

Ventral distraction-stabilization technique with custom-designed FITS and a polyaxial spinal system resulted in both clinical improvement and objective improvement in spinal canal measurements in an OA-CSM-affected Great Dane.

CLINICAL SIGNIFICANCE

An indirect decompression technique can eliminate dynamic movements and result in regression of vertebral canal bony proliferation in dogs with OA-CSM.

Development of a finite element model of the ligamentous cervical vertebral column of a Great Dane

Cervical spondylomyelopathy (CSM), also known as wobbler syndrome, affects mainly large and giant-breed dogs, causing compression of the cervical spinal cord and/or nerve roots. Structural and dynamic components seem to play a role in the development of CSM; however, pathogenesis is not yet fully understood. Finite element models have been used for years in human medicine to study the dynamic behavior of structures, but it has been mostly overlooked in veterinary studies. To our knowledge, no specific ligamentous spine models have been developed to investigate naturally occurring canine myelopathies and possible surgical treatments. The goal of this study was to develop a finite element model (FEM) of the C₂-C₇ segment of the ligamentous cervical vertebral column of a neurologically normal Great Dane without imaging changes. The FEM of the intact C₂-C₇ cervical vertebral column had a total of 188,906 elements (175,715 tetra elements and 12,740 hexa elements). The range of motion (in degrees) for the FEM subjected to a moment of 2Nm was approximately 27.94 in flexion, 25.86 in extension, 24.14 in left lateral bending, 25.27 in right lateral bending, 17.44 in left axial rotation, and 16.72 in right axial rotation. We constructed a ligamentous FEM of the C₂-C₇ vertebral column of a Great Dane dog, which can serve as a platform to be modified and adapted for studies related to biomechanics of the cervical vertebral column and to further improve studies on osseous-associated cervical spondylomyelopathy.

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.

Cranial thoracic vertebral canal stenosis in three juvenile large-breed brachycephalic dogs treated by unilateral hemilaminectomy

Objective: To describe the surgical treatment and outcome for juvenile dogs with cranial thoracic vertebral canal stenosis treated by unilateral hemilaminectomy.

Study design: Case series.

Animals: Three large-breed brachycephalic dogs of various breeds (Dogue de Bordeaux, Australian Bulldog, Boerboel) with neurological signs consistent with a myelopathy of the third thoracic (T) to third lumbar (L) spinal cord segment.

Methods: Information on clinical presentation, diagnostic imaging, surgical procedures, postoperative complications, recovery and outcome is described.

Results: Neurological signs were present and progressive for two to four weeks prior to surgery and ranged from mild ataxia to paralysis. Cranial thoracic vertebral canal stenosis was diagnosed with computed tomography imaging. Lateral and dorsolateral spinal cord compression was present at multiple sites between T2 and T6. Alternating left and right-sided compressions were common. Surgical treatment was by unilateral, continuous hemilaminectomy over three to six vertebral spaces. Postoperative morbidity was minimal and return of independent ambulation was rapid (median: 13.5 days, range: 2–29 days). Neurological status in one dog worsened four months after surgery due to reoccurrence of osseous compression; unilateral hemilaminectomy was repeated in this dog. Long-term follow-up ranged from six to 10 months; neurological signs had completely resolved in one dog and substantially improved in the other two dogs.

Clinical significance: Unilateral hemilaminectomy was associated with rapid return of independent ambulation and substantial improvement in neurological scores.

Perineural Injection for Treatment of Root-Signature Signs Associated with Lateralized Disk Material in Five Dogs (2009-2013)

Intervertebral disk disease (IVDD) is common in dogs; cervical IVDD accounts for 13–25% of all cases. Ventral slot decompression provides access to ventral and centrally extruded or protruded disk material. However, procedures to remove dorsally or laterally displaced material are more difficult. This case series describes the use of perineural injection as a potential treatment option for dogs experiencing root-signature signs associated with lateralized disk material in the cervical spine. Five dogs underwent fluoroscopically guided perineural injection of methylprednisolone ± bupivacaine. Most patients experienced improvement in root-signature signs and remained pain free without the assistance of oral pain medication. These findings suggest the perineural injection of methylprednisolone ± bupivacaine represents a viable option for dogs with cervical lateralized disk material causing root-signature signs.

Risk factors for early post-operative neurological deterioration in dogs undergoing a cervical dorsal laminectomy or hemilaminectomy: 100 cases (2002-2014)

Early post-operative neurological deterioration is a well-known complication following dorsal cervical laminectomies and hemilaminectomies in dogs. This study aimed to evaluate potential risk factors for early post-operative neurological deterioration following these surgical procedures. Medical records of 100 dogs that had undergone a cervical dorsal laminectomy or hemilaminectomy between 2002 and 2014 were assessed retrospectively. Assessed variables included signalment, bodyweight, duration of clinical signs, neurological status before surgery, diagnosis, surgical site, type and extent of surgery and duration of procedure. Outcome measures were neurological status immediately following surgery and duration of hospitalisation. Univariate statistical analysis was performed to identify variables to be included in a multivariate model. Diagnoses included osseous associated cervical spondylomyelopathy (OACSM; n = 41), acute intervertebral disk extrusion (IVDE; 31), meningioma (11), spinal arachnoid diverticulum (10) and vertebral arch anomalies (7). Overall 54% (95% CI 45.25-64.75) of dogs were neurologically worse 48 h post-operatively. Multivariate statistical analysis identified four factors significantly related to early post-operative neurological outcome. Diagnoses of OACSM or meningioma were considered the strongest variables to predict early post-operative neurological deterioration, followed by higher (more severely affected) neurological grade before surgery and longer surgery time. This information can aid in the management of expectations of clinical staff and owners with dogs undergoing these surgical procedures.

Clinical reasoning in canine spinal disease: what combination of clinical information is useful?

Spinal disease in dogs is commonly encountered in veterinary practice. Numerous diseases may cause similar clinical signs and presenting histories. The study objective was to use statistical models to identify combinations of discrete parameters from the patient signalment, history and neurological examination that could suggest the most likely diagnoses with statistical significance. A retrospective study of 500 dogs referred to the Queen Mother Hospital for Animals before June 2012 for the investigation of spinal disease was performed. Details regarding signalment, history, physical and neurological examinations, neuroanatomical localisation and imaging data were obtained. Univariate analyses of variables (breed, age, weight, onset, deterioration, pain, asymmetry, neuroanatomical localisation) were performed, and variables were retained in a multivariate logistic regression model if P<0.05. Leading diagnoses were intervertebral disc extrusion (IVDE, n=149), intervertebral disc protrusion (n=149), ischaemic myelopathy (IM, n=48) and neoplasms (n=44). Multivariate logistic regression characterised IM and acute non-compressive nucleus pulposus extrusions as the only peracute onset, non-progressive, non-painful and asymmetrical T3-L3 myelopathies. IVDE was most commonly characterised as acute onset, often deteriorating, painful and largely symmetrical T3-L3 myelopathy. This study suggests that most spinal diseases cause distinctive combinations of presenting clinical parameters (signalment, onset, deterioration, pain, asymmetry, neuroanatomical localisation). Taking particular account of these parameters may aid decision making in a clinical setting.