Clinical presentation and outcome of dogs treated medically or surgically for thoracolumbar intervertebral disc protrusion

Common Neurologic Diseases in Geriatric Dogs

The increase in the canine geriatric population means that veterinarians are more often confronted with diseases that are more prevalent in patients in this age group. As in other organ systems, degenerative, neoplastic, and vascular diseases are the most prevalent neurologic disorders in older dogs. A neurological disease in an older dog poses a challenge for the clinician due to the presence of concomitant diseases and age-related changes that make it difficult to interpret the neurological examination. In addition, given the age of the patients, some owners do not allow advanced imaging tests, and it is necessary to establish the most likely presumptive diagnosis to initiate treatment. Although many of these diseases can cause clinical signs that can be very upsetting, some of them can be managed with symptomatic therapy and have a good prognosis, such as idiopathic vestibular syndrome. Moreover, advances in and the greater availability of therapeutic options such as surgery and radiation therapy may increase survival and quality of life in diseases with a more serious prognosis, such as tumours. The aim of this review is to summarize the clinical presentation, diagnosis, and treatment of the more frequent diseases affecting the central nervous systems of geriatric dogs.

Outcomes of surgically and conservatively managed thoracolumbar and lumbosacral intervertebral disc herniations in cats

BACKGROUND

Limited information is available regarding intervertebral disc herniation (IVDH) and its treatment in cats.

OBJECTIVES

Describe outcomes after surgical or conservative treatment of cats with thoracolumbar and lumbosacral IVDH.

ANIMALS

Ninety-two cats from 2 referral populations (2012-2022) with compressive IVDH between the T3 and S1 vertebrae.

METHODS

Retrospective cohort study evaluating outcomes of surgical (49 cats) and conservative (36 cats) management of IVDH; 7 cats were euthanized at diagnosis. Outcome was assessed using hospital and referring veterinarian records and client questionnaires. Successful outcome was defined as regained or improved ambulation, urinary and fecal continence, and no requirement for analgesic medication.

RESULTS

Incidence of IVDH during the study period was 0.44% (92/20849). Surgical treatment resulted in 62% (6 weeks) and 74% success (6 months). Conservative treatment resulted in 54% (6 weeks) and 65% success (6 months). Neurological grade at presentation was higher in cats treated surgically (median, 2; range, 1-5) than in those treated conservatively (median, 2; range, 0-4; P = .001). Regardless of treatment type, cats suffering trauma were more likely to have a successful outcome 6 weeks after treatment compared with those without history of trauma (odds ratio, 5.3; 95% confidence interval, 1.05-26.78; P = .04). Neurological deficits remained in the majority of cats for both treatment types (92%, conservative; 86%, surgical at 6 weeks). Acute-on-chronic IVDH with characteristics of both extrusion and protrusion were identified in 10% of cats.

CONCLUSIONS AND CLINICAL IMPORTANCE

Conservative treatment could be as effective as surgical decompression in cats with thoracolumbar or lumbosacral IVDH.

MRI and clinical findings in 133 dogs with recurrent deficits following intervertebral disc extrusion surgery

BACKGROUND

Recurrence of neurological signs following surgery for intervertebral disc herniation (IVDH) is reported, yet many cases lack MRI-confirmed diagnosis. This study describes the MRI and clinical findings in dogs presenting with recurrence of neurological signs following surgical treatment of IVDH.

METHODS

Medical records of dogs that underwent decompressive surgery for IVDH followed by a subsequent MRI within 12 months were retrospectively reviewed.

RESULTS

One hundred and thirty-three dogs were identified, all of which initially presented with intervertebral disc extrusion (IVDE). Of these, 109 (81.9%) had a recurrent IVDE, and 24 (18.1%) had an alternative diagnosis that included haemorrhage (n = 10), infection (n = 4), soft tissue encroachment (n = 3), myelomalacia (n = 3) or other (n = 4). Same-site IVDE recurrence or alternative diagnoses were significantly more likely to present within 10 days postoperatively. Thirty-nine percent of dogs presenting with 'early recurrence' had an alternative diagnosis. Type of surgery, fenestration, neurological grade or IVDE site was not significantly associated with the subsequent MRI diagnosis.

LIMITATIONS

Limitations include the retrospective study design, the exclusion of conservatively managed recurrences, the variable length of follow-up and differences in the clinicians' surgical experience.

CONCLUSION

The most common cause for the recurrence of neurological signs following decompressive spinal surgery was IVDE. Just over one-third of dogs presenting with early recurrence had an alternative diagnosis.

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.

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.

Classification of Intervertebral Disc Disease

Intervertebral disc disease (IVDD) has been recognized in dogs since the 1800s, when the first descriptions of extruded disc material within the vertebral canal were published. In the intervening time our understanding of intervertebral disc pathology in dogs and cats has increased dramatically, with many variations of IVDD described. Whilst the volume of literature and collective understanding of IVDD has expanded, there has also been scope for confusion as the definition of intervertebral disc disease, with its myriad different manifestations, becomes more complicated. A large volume of literature has aimed to combine the use of histopathology, diagnostic imaging and clinical findings to better understand the various ways in which IVDD can be classified. Much of this research has focused on the classification of mechanisms of intervertebral disc degeneration, centering around the differences between, and overlaps in, IVDD in chondrodystrophic and non-chondrodystrophic dog breeds. However, with the increasing availability of advanced imaging modalities allowing more accurate antemortem diagnosis, the concept of IVDD has expanded to include other clinical presentations that may not fit into traditional models of classification of IVDD. This review aims to provide an up to date overview of both historical and current systems of IVDD classification, highlighting the important findings and controversies underpinning them.

Minimally invasive microsurgical decompression of an intervertebral disc protrusion in a dog

OBJECTIVE

To report the successful treatment of intervertebral disc protrusion with minimally invasive microsurgery in a large breed dog.

STUDY DESIGN

Retrospective case report.

ANIMAL

A 4-year-old, neutered male, German shepherd dog presented with chronic progressive ambulatory paraparesis and thoracolumbar pain; lumbar intervertebral disc protrusion and severe spinal cord compression at L2-L3 were diagnosed.

METHODS

A minimally invasive approach was used to access the target surgical area by using a muscle splitting technique and retractors. Intraoperative fluoroscopy confirmed correct placement. Magnification and illumination through a surgical microscope were used (microsurgery) to perform the spinal cord decompression by means of a foraminotomy and lateral corpectomy.

RESULTS

Technically, the combination of fluoroscopy and muscle splitting approach offered adequate minimally invasive access. Microsurgery allowed for precise and efficient spinal cord decompression. Clinically, no immediate postoperative neurological deterioration was observed. Opioid usage was limited to 24 hours postoperatively. Focal muscle swelling was observed postoperatively for 2 days, and hospital stay was 3 days. At 7 weeks postoperatively, neurological examination results were normal, and postoperative MRI confirmed spinal cord decompression. No complications were reported.

CONCLUSION

The procedure was associated with a small incision, limited muscle trauma, early improvement of the neurological status, a short hospital stay, and limited postoperative pain.

CLINICAL SIGNIFICANCE

This case provides evidence that minimally invasive microsurgery is an effective treatment for intervertebral disc protrusion in large breed dogs and may offer benefits regarding postoperative pain and functional recovery.

Comparison of medical and surgical treatment for acute cervical compressive hydrated nucleus pulposus extrusion in dogs

Although successful outcomes have been reported after medical and surgical treatment for dogs with cervical hydrated nucleus pulposus extrusion (HNPE), it is unknown which treatment option is preferred. Thirty-four dogs treated medically (n=18) or surgically (n=16) for cervical HNPE were retrospectively identified. Signalment, clinical presentation and imaging findings were compared between medically and surgically treated dogs. Medical management consisted of restricted exercise in combination with physiotherapy. Surgical treatment consisted of a ventral slot procedure. Short-term follow-up information was retrieved from re-examination visits. Long-term outcome was obtained via telephone interviews. More dogs in the surgical group demonstrated cervical hyperaesthesia on initial clinical presentation (P=0.045), otherwise there was no significant difference in signalment, clinical presentation or imaging findings between both groups. Two dogs in the medically managed group underwent surgical decompression due to an unsatisfactory response to medical management. All cases for which long-term information was available (n=30) were neurologically normal at the time of data collection. There were no significant differences for any of the short-term or long-term outcome variables between both treatment groups. This study demonstrated successful outcomes after medical or surgical treatment and suggests that both treatment modalities can be considered for dogs with cervical HNPE.