Early Reherniation of Disk Material in Eleven Dogs with Surgically Treated Thoracolumbar Intervertebral Disk Extrusion

Objective: To report findings and outcomes of dogs with reherniation of nuclear material within 7 days of hemilaminectomy for acute thoracolumbar (TL) intervertebral disk extrusion. Study Design: Retrospective case series. Animals: Chondrodystrophic dogs (n = 11). Methods: Dogs with acute neurologic decline within 1 week of surgical decompression for TL disk extrusion were identified. Advanced imaging was used to document extradural spinal cord compression at the previous surgery site. Ten dogs had a 2nd decompressive surgery to remove extruded nuclear material. Results: All dogs had acute neurologic deterioration (average, 2 neurologic grades) 2-7 days after initial hemilaminectomy. Computed tomography (CT; n = 10) or myelography (n = 1) documented extradural spinal cord compression compatible with extruded disk material at the previous hemilaminectomy site. Dogs that had a 2nd surgical decompression improved neurologically within 24 hours and were paraparetic at discharge. The single dog that did not have decompressive surgery did not regain deep nociception during 185-day follow-up. Conclusions: Early reherniation at the site of previous hemilaminectomy can produce acute deterioration of neurologic function and should be investigated with diagnostic imaging. Repeat decompressive surgery can lead to functional recovery.