Partial lateral corpectomy of the thoracolumbar spine in 51 dogs: assessment of slot morphometry and spinal cord decompression.

OBJECTIVE To report slot morphometry, degree of spinal decompression, and factors influencing decompression after partial lateral corpectomy (PLC) of the thoracolumbar spine in dogs with intervertebral disc disease. STUDY DESIGN Case series. ANIMALS Dogs (n=51) with predominantly ventrally located spinal cord compression. METHODS PLC (n=60) were performed. Spinal cord compression was determined by computed tomographic (CT) myelography (n=46), myelography (n=2) or magnetic resonance imaging (n=3). Postsurgical CT images were used to evaluate slot dimensions and orientation, and spinal cord decompression. The influence of age, body weight, breed, breed type (chondrodystrophic, nonchondrodystrophic), disc location, lateralization and mineralization, presurgical compression, slot morphometry, and surgeon on degree of decompression were evaluated. RESULTS Mean slot depth was 64.1% of vertebral body width; mean height, 43.0% of vertebral body height; mean cranial extension, 29.5%; median caudal extension, 22.0% vertebral body length; mean angulation from horizontal, 6.3°. Decompression was satisfactory in 90% of sites after PLC (58% complete, 32% good). None of the analyzed factors significantly influenced decompression. All lumbar spine PLC resulted in complete or good decompression compared with 83% after thoracic PLC (P=.052). Deeper slots tended to allow more complete decompression (P=.058). CONCLUSIONS Thoracolumbar PLC results in satisfactory decompression in most cases with a better outcome in the lumbar spine than the thoracic spine. Achieving a slot depth equal to 2/3 of vertebral body width might facilitate complete decompression.