Thoracolumbar Intervertebral Disk Extrusion in Dogs: Do Onset of Clinical Signs, Time of Surgery, and Neurological Grade Matter?

The aim of this study was to determine the influence of time between the beginning of clinical signs, presentation and decompression, and combinations of several factors on the outcome and recovery of dogs undergoing surgery for thoracolumbar intervertebral disk extrusion (IVDE). In all, 433 client-owned dogs treated for IVDE between 2016 and 2020 were reviewed for signalment, neurological grade, rate of onset, duration of clinical signs, and surgical variables. Time from presentation to surgery was divided into three categories: S1 (0-12 hours), S2 (12-24 hours), and S3 (>24 hours). These variables were investigated to determine their influence on the return of pain sensation, urinary continence, ambulation and overall outcome. A significant association was found between an acute onset of clinical signs, worse neurological grade at presentation and poorer outcomes. There was a significant difference between S1, S2, and S3 in neurological grade at presentation (p < 0.001) and at discharge (p < 0.001); however, the latter was no longer significant when adjusted for the grade at presentation (p = 1,000). Disk fenestration was associated with a faster return to ambulation (p = 0.033). Duration of clinical signs and time of surgery did not correlate with the time to recovery and return of pain sensation, urinary continence, or ambulation. Dogs presented with severe neurological status and/or rapid onset of clinical signs were operated on more promptly, but their outcomes were also poorer. There was no significant evidence for a better outcome when surgery was not delayed.