Objective: To examine associations between CSF biomarkers, initial neurologic dysfunction, and long-term ambulatory outcome in dogs with acute intervertebral disk herniation (IVDH).

Design: Prospective clinical study.

Animals: 54 dogs with acute thoracolumbar IVDH and 16 clinically normal dogs.

Procedures: For each dog, variables, including CSF myelin basic protein (MBP), lactate, calcium, glucose, and total protein concentrations; nucleated cell count; and creatine kinase (CK) and aspartate aminotransferase activities, were measured. For dogs with thoracolumbar IVDH, initial neurologic function was characterized by use of a modified Frankel score (MFS; determined on a scale of 0 to 5, where 0 represented paraplegia with no deep nociception and 5 represented paraspinal hyperesthesia only). Long-term follow-up was assessed.

Results: Among dogs with thoracolumbar IVDH, those with CSF CK activity ≤ 38 U/L had a 35-fold increase in the odds of long-term ambulation, compared with the odds in dogs with CSF CK activity > 38 U/L, adjusting for neurologic functioning at the evaluation. The CSF lactate, calcium, and glucose concentrations and aspartate aminotransferase activity were not predictive of long-term ambulatory outcome. Data analysis revealed that long-term functional recovery was > 98% for affected dogs, regardless of their initial MFS, when CSF CK activity was ≤ 38 U/L and MBP concentration was ≤ 3 ng/mL.

Conclusions and clinical relevance: In dogs with acute thoracolumbar IVDH, CSF CK activity and MBP concentration appeared to be prognostic indicators and, along with initial MFS, can be used to predict long-term ambulatory outcome.