Hemilaminectomy and vertebral stabilization for thoracolumbar intervertebral disc associated dynamic compression in 11 dogs

Objective: To describe the diagnostic findings, surgical technique and outcome in dogs with thoracolumbar intervertebral disc-associated dynamic compression. Study design: Retrospective case series. Animals: Client owned dogs (n = 11). Methods: Medical records (2005–2010) of dogs with a stress myelographic diagnosis of spinal cord injury due to thoracolumbar intervertebral disc-associated dynamic compression with inconclusive compression in the neutral myelographic views that had hemilaminectomy and vertebral stabilization were reviewed. Data on pre- and postoperative neurologic status, diagnostic findings, surgical techniques and outcomes were retrieved. Follow-up clinical and radiographic evaluations were performed immediately, and at approximately one, two, and six months postoperatively as well as at annual follow-up examinations. Results: The stress myelography demonstrated distinct ventral dynamic compression due to bulging of the disc and additional dorsal compression due to infolding of the ligamentum flavum in some cases. The median percentage of post-stress reduction in spinal cord height on the lateral view was 18.0% (9.8-27.2%). All dogs recovered after surgery and at follow-up examinations were still ambulatory (median: 45 months, range: 7 to 94 months). Conclusions and clinical relevance: Thoracolumbar intervertebral disc degeneration may result in disc-associated dynamic compression. Stress myelography was an effective means of diagnosing this condition and hemilaminectomy with vertebral stabilization was an effective treatment resulting in long-term neurological improvement in all dogs.