Cervical vertebral instability (wobbler syndrome) in the dog.

Observations on a series of 38 cases (35 Doberman Pinschers and three Great Danes) of the canine wobbler syndrome are described. Radiographic examinations suggested that the primary lesion is an intervertebral instability at C6/7, but with time, secondary changes of the disc degeneration and prolapse and vertebral body malformation causing stenosis of the vertebral canal occur. Cases detected at a young age and showing only the primary lesion were treated successfully, by disc fenestration alone or by disc fenestration and intervertebral screwing. The success rate in older cases with secondary lesions was poor and in this type of case, cord decompression by dorsal laminectomy appears necessary.     

Cervical spondylomyelopathy ('wobbler' syndrome) in the dog: A study based on 224 cases

Over the past 10 to 12 years, cervical spondylomyelopathy has been increasingly recognised in large breed dogs. The breeds mainly affected are dobermanns, great danes and basset hounds. Factors such as age, sex and location of the lesions are discussed in detail based on findings from 224 cases seen at the University of Liverpool Small Animal Hospital. The anatomical changes responsible for the signs show some striking similarities in young dogs of all the breeds affected. Where the condition is commoner later in life, such as in the dobermann, the changes and their effect on the spinal cord show considerable differences. These different findings are compared, and an attempt made to explain them.     

Disc-associated wobbler syndrome in the Doberman pinscher

Disc-associated wobbler syndrome is a subset of the diverse canine wobbler complex. Disc-associated wobbler disease can occur in many large-breed dogs but the vast majority are middle-aged Doberman Pinschers. Dorsal annulus hypertrophy and protrusion is the hallmark lesion with variable association of dorsal ligamentum flavum hypertrophy and bony malformations. Chronic caudal cervical spinal cord compression results in the clinical signs. Instability, primary disc degeneration, and conformational etiologies have been incriminated. The clinical course usually entails chronic progressive paraparesis to tetraparesis with insidious onset. Acute onset or exacerbations are less common. Diagnosis is based upon history, neurologic examination, and radiography/myelography. Long-term conservative therapy is only palliative and usually leads to the demise of the animal. Surgical therapy offers the potential of a cure but at significant risk of morbidity and mortality. Surgical treatment consists primarily of decompressive techniques with or without stabilization. The numerous surgical techniques utilized highlight the variability of the lesions and the lack of universal acceptance of any one technique. Decompression is accomplished by surgical access to the vertebral canal to physically remove the abnormal ligament and/or bony material. Alternatively, distraction combined with fusion of the vertebrae adjacent to the offending disc may reduce the hypertrophied/prolapsed dorsal annulus. Regardless of the procedure, postoperative management may be fraught with complications that require special considerations.     

Caudal cervical spondylo-myelopathy (wobbler syndrome) in the dog: a review of thirty cases

Caudal cervical spondylo-myelopathy was diagnosed in 30 cases admitted to the University of Queensland Veterinary Clinic (UQVC) over a four-year period. The clinical signs at presentation and the radiographic changes detected varied considerably. A number of different surgical treatments were used and a small number of animals were treated conservatively. The results are presented, followed by some discussion concerning the aetiology and pathogenesis of this condition.     

Treatment of wobbler syndrome in dogs with electroacupuncture

Based on favorable experiences with acupuncture for the treatment of hind limbs paralysis, lumbo-sacral alterations, and other spinal cord problems; a clinical trial, involving 40 dogs affected with wobbler syndrome was carried out. Patients were graded in three categories according to the severity of each case and then randomly divided in two groups. Both groups contained all three grades. Group 1 (20 dogs) was treated using orthodox medical and surgical interventions, while Group 2 (20 dogs) were treated mainly with electroacupuncture, and in few cases with surgical intervention as well. The study was carried out in a three-year period. Acupuncture treatments were given every other day delivering 150 to 300 mVolts at 125 Hz, equivalents to approximately 20 microAmps, in ten acupuncture points per treatment. Deep needle insertion was used. Overall per cent success in Group I was only 20%, while in group II the corresponding value was 85%. The number of acupuncture treatments required to achieve full recovery in Group II was dependent upon the severity of the case, as follows: Grade I: 18.5 +/- 2.5; Grade II: 25 +/- 5.4; and Grade III: 34 +/- 6.7 (r = 0.962). No adverse effects were observed with acupuncture. The use of this technique is proposed for large-scale clinical trials.     

Radiological evaluation of 'wobbler' syndrome -caudal cervical spondylomyelopathy

Caudal cervical spondylomyelopathy (‘wobbler’ syndrome) is a common neurological disorder of large and giant breed dogs. Diagnostic evaluation requires radiological assessment, including plain radiography and myelography. Computed tomography can be used to give additional information on vertebral and spinal cord disease. This paper reviews plain radiographic and myelographic techniques and findings in caudal cervical spondylomyelopathy. The value of computed tomographic myelography is also reviewed. The relevance of the conventional radiological and computed tomographic findings to surgical treatment are discussed. Similarities between this condition and cervical spondylotic myelopathy in man are also examined.     

Surgery for disc-associated wobbler syndrome in the dog--an examination of the controversy.

Controversy surrounds treatment of disc-associated 'wobbler' syndrome in the dog, centring on the choice of method of surgical decompression used. In this review, details of previously published case series are summarised and critically examined in an attempt to compare success rates and complications of different types of surgery. Unequivocally accurate comparisons were difficult because of differences in methods of case recording between series. Short-term success rates were high (approximately 80 per cent), but there was a high rate of recurrence (around 20 per cent) after any surgical treatment, suggesting the possibility that the syndrome should be considered a multifocal disease of the caudal cervical region. Statistical analysis revealed no significant differences in success rates between the various reported decompressive surgical techniques     

Canine wobbler syndrome: A study of the Dobermann pinscher in New Zealand

The aim of this study was to investigate the prevalence of wobbler disease within a Dobermann pinscher population from three geographical locations in New Zealand. The study population consisted of 138 adults (aged 1–13 years) and 32 puppies (aged 6 weeks to 11 months). Data collected for each dog included age, sex, geographic location, if a choker chain was used or not and, in adults, the following body measurements: dimensions of head length, head circumference, width between shoulders, neck length, height at withers and withers to rump length. In addition, lateral radiographs were taken of the caudal cervical vertebrae of each dog and the radiological abnormalities associated with wobbler disease scored, so that each dog could be assigned to one of three radiological groupings. Based upon a neurological examination, each animal was also placed into one of three neurological groupings. The relationship between radiological and neurological groupings and the independent variables was initially compared using a univariate and subsequently a multivariate analysis.

It was found that 48.8% of the dogs investigated had some abnormal radiological sign associated with wobbler disease, and 32.0% of them showed neurological signs. Dogs with radiological signs of the disease were 5.56 times more likely to have neurological signs. Statistical analysis of the data indicated that more severe radiological and neurological abnormalities occurred in the older dogs. In addition, dogs located in Hawke's Bay region had less chance of showing radiological changes than dogs from the other two regions, Hamilton and Wellington. Twelve of the 32 puppies were examined for radiological and neurological changes over the first year of their life. No abnormalities were detected in puppies under 12 weeks of age, but 28% (n=9) of the 32 puppies over 3 months of age did show some radiological changes. Only 9%(n=3) of puppies showed any neurological signs. Although several pedigree lines were investigated, the lineage data were incomplete, and therefore there was no conclusive evidence that wobbler disease was an inherited trait.

This study showed that, although the radiological signs of wobbler disease were present throughout a wide age range, the associated neurological changes tended to appear at a later age. In both instances, the severity of these changes increased with age.     

Canine wobbler syndrome: a study of the Dobermann pinscher in New Zealand

The aim of this study was to investigate the prevalence of wobbler disease within a Dobermann pinscher population from three geographical locations in New Zealand. The study population consisted of 138 adults (aged 1-13 years) and 32 puppies (aged 6 weeks to 11 months). Data collected for each dog included age, sex, geographic location, if a choker chain was used or not and, in adults, the following body measurements: dimensions of head length, head circumference, width between shoulders, neck length, height at withers and withers to rump length. In addition, lateral radiographs were taken of the caudal cervical vertebrae of each dog and the radiological abnormalities associated with wobbler disease scored, so that each dog could be assigned to one of three radiological groupings. Based upon a neurological examination, each animal was also placed into one of three neurological groupings. The relationship between radiological and neurological groupings and the independent variables was initially compared using a univariate and subsequently a multivariate analysis. It was found that 48.8% of the dogs investigated had some abnormal radiological sign associated with wobbler disease, and 32.0% of them showed neurological signs. Dogs with radiological signs of the disease were 5.56 times more likely to have neurological signs. Statistical analysis of the data indicated that more severe radiological and neurological abnormalities occurred in the older dogs. In addition, dogs located in Hawke's Bay region had less chance of showing radiological changes than dogs from the other two regions, Hamilton and Wellington. Twelve of the 32 puppies were examined for radiological and neurological changes over the first year of their life. No abnormalities were detected in puppies under 12 weeks of age, but 28% (n=9) of the 32 puppies over 3 months of age did show some radiological changes. Only 9% (n=3) of puppies showed any neurological signs. Although several pedigree lines were investigated, the lineage data were incomplete, and therefore there was no conclusive evidence that wobbler disease was an inherited trait. This study showed that, although the radiological signs of wobbler disease were present throughout a wide age range, the associated neurological changes tended to appear at a later age. In both instances, the severity of these changes increased with age.     

Clinical evaluation of 51 dogs treated conservatively for disc-associated wobbler syndrome

O bjectives : To evaluate the clinical evolution and potential risk factors of 51 dogs treated conservatively for disc-associated wobbler syndrome.
M ethods : Medical records of dogs treated conservatively for disc-associated wobbler syndrome were reviewed, and owners were contacted regarding clinical evolution and survival of their animals. Relationships between age, treatment before diagnosis, type of neurological signs, results of medical imaging and outcome were determined.
R esults : Fifty-one dogs underwent conservative treatment for disc-associated wobbler syndrome. A successful outcome was achieved in 45 per cent (23 of 51) of the patients. Median follow-up period was 18.5 months, and median survival time was 47 months. In 85 per cent of the dogs in which euthanasia was performed because of disc-associated wobbler syndrome, this was carried out in the first year after diagnosis. Outcome score was influenced by type of neurological signs and additional radiographic and/or myelographic abnormalities. Outcome score was not significantly associated with age, number of protruded intervertebral discs, occurrence, type and results of treatment before diagnosis.
C linical S ignificance : Conservative treatment of disc-associated wobbler syndrome is associated with a guarded prognosis. It can be considered in cases where all four limbs are not affected and no additional radiographic and/or myelographic abnormalities are detected.     

Clinical and magnetic resonance imaging (MRI) findings in 26 dogs with canine osseous-associated cervical spondylomyelopathy

The potential link between degenerative changes seen on magnetic resonance imaging (MRI) in osseous-associated cervical spondylomyelopathy (OA-CSM) and clinical signs has not been explored. Our goal was to retrospectively evaluate MRI findings, while investigating potential correlations between these changes, signalment, and clinical signs. Twenty-six dogs diagnosed with OA-CSM were included in the study. Clinical signs were converted into a Modified Frankel Score (MFS) and MRI findings were assessed and graded. Giant breeds had multiple compressed sites and presented at a younger age than large breeds, suggesting a different underlying pathophysiology. Spinal cord compression, most commonly bilateral, was present in 36.8% of intervertebral spaces. Synovial fluid loss and articular process sclerosis were the most common degenerative changes. Most dogs showed identical MFS scores, and no significant correlations were found between MFS and MRI changes. More detailed functional scales should be used to investigate this in the future.     

Surgical treatment of disk-associated wobbler syndrome by a distractable vertebral titanium cage in seven dogs

Objective: To evaluate a distractable titanium cage for the treatment of disk‐associated wobbler syndrome (DAWS). Study Design: Prospective study. Animals: Dogs (n=7) with DAWS. Methods: After total discectomy of C5–C6 and C6–C7, the median part of the vertebral body of C6 was removed with preservation of the lateral walls and dorsal cortex. The removed cancellous bone was collected. The implant was placed in the bony defect of C6. After placement, the titanium cage was distracted and affixed by 4 screws. Finally, the implant was filled and covered with cancellous bone. Dogs had follow‐up examinations at 1, 3, 6, 12, and 24 months. Six months after surgery, cervical radiographs and computed tomography (CT) were performed. Results: Although no intraoperative complications occurred, correct placement of the cage was technically challenging. Revision surgery was necessary in 2 dogs because of implant loosening and aggravation of vertebral tilting. All dogs improved after discharge from the hospital. In 1 dog, recurrence of clinical signs caused by articular facet proliferation at an adjacent intervertebral disk space occurred. Radiographs at 6 months demonstrated cage subsidence in 4 dogs. In all dogs, CT was suggestive for fusion of the bone graft with the vertebral body. Conclusions: Although results are promising, technical adaptations will be necessary to make this specific surgical technique, designed for humans, suitable for routine use in dogs.     

Management of disc-associated wobbler syndrome with a partial slot fenestration and position screw technique

A previously unpublished surgical technique for the management of disc-associated wobbler syndrome is described. A series of 17 middle-aged dobermanns (mean age 7·4 years) with this condition were managed by a technique of partial slot fenestration and position screw fixation of the affected disc space (C6/7 in all cases). One patient was lost to follow-up and, of the remaining 16 cases, 13 improved following surgery (81 per cent). The three failures were a consequence of incorrect placement of one of the screws. Careful evaluation of immediate postoperative radiographs allows this problem to be identified; the screw can then be correctly repositioned with an immediate return to surgery.     

Ventral stabilization and facetectomy in a Great Dane with wobbler syndrome due to cervical spinal canal stenosis

This report describes the management of clinically significant, single level cervical spinal canal stenosis associated with articular facet hypertrophy in a three-year-old Great Dane dog, by combined surgical decompression and spinal stabilization. Spinal column stabilization was achieved by ventral application of two String of Pearls locking plates and subsequent decompression was accomplished by unilateral facetectomy. The six-month postoperative reassessment examination confirmed satisfactory clinical outcome with a complete return to normal activity, resolution of neurological deficits and maintenance of implant positioning.     

Bilateral multiple cystic kidney disease and renal cortical abscess in a Boerboel

Cystic renal disease is rare in dogs and although infected renal cysts have been reported in humans, no report could be found in dogs. A 58 kg, 5-year-old, castrated, male Boerboel presented with weight loss, pyrexia, lethargy and vomiting, 20 months after an incident of haematuria was reported. The initial ultrasonographic diagnosis was bilateral multiple renal cysts of unknown aetiology. The cysts had significantly increased in size over the 20-month period and some contained echogenic specks which could be related to infection, normal cellular debris or haemorrhage. In both kidneys the renal contours were distorted (the left more than the right). The abnormal shape of the left kidney was largely due to multiple cysts and a large crescent-shaped septate mass on the cranial pole of the kidney. Aspirates of the septate mass were performed (left kidney) and the cytology and culture were indicative of an abscess. It is suggested that the previous incident of haematuria provided a portal of entry for bacteria into the cysts resulting in renal cortical abscess formation.     

Canine multifocal retinopathy caused by a BEST1 mutation in a Boerboel

A 7‐month‐old male intact Boerboel presented to the Cummings School of Veterinary Medicine at Tufts University for the evaluation of ocular discharge. Bilateral multifocal serous retinal detachments were noted on fundus examination as an incidental finding. Genetic testing confirmed the dog to be homozygous for a mutation in the BEST1 gene, where a C₇₃T/R₂₅X change results in premature termination codon. Further testing, including electroretinography and optical coherence tomography (OCT), demonstrated that there was no evidence of retinal photoreceptor dysfunction and confirmed that observed lesions were characteristic of canine multifocal retinopathy. No progression of the lesions was noted 3 months after the initial examination. To the authors’ knowledge, this is the first report of canine multifocal retinopathy in the Boerboel breed.