Objective: To report the frequency, types, and risk factors for acute perioperative adverse events (AEs) in dogs that had ventral slot decompression (VSD) for cervical intervertebral disc disease (IVDD).

Design: Retrospective, case-control study.

Animals: Dogs (n = 546) with cervical IVDD treated by VSD; 54 cases experiencing AE and 492 controls.

Methods: Historical, clinical, diagnostic, operative, and outcome data were collected. AE were graded using a Spine Adverse Events Severity (SAVES) system. Associations between the development of AE and hypothesized risk factors were analyzed using bi- and multi-variable analyses.

Results: AE were observed in 54 dogs (9.9%). Minor AE (SAVES Grade 1-2) occurred in 3.5% (19 dogs) and major (SAVES Grades 3-5) AE in 6.4% (35 dogs). Deterioration in neurologic status (n = 13), persistent pain (12), and intraoperative hemorrhage (7) were common major AE. NSAID administration, surgeon experience, C7-T1 disc location, and intraoperative hypotension were significantly associated with AE in multivariate analyses. Improvement of AE occurred in 48/54 (88.9%) of cases, although reoperative neurosurgery was required in 48.5% (17/35) of dogs experiencing major AE. Dogs with major AE had significantly longer hospitalization and worse outcomes than dogs with minor AE or controls. No fatal AE occurred, although 0.7% (4/546) of dogs were euthanatized postoperatively.

Conclusions: AE occurred in 9.9% of dogs that had VSD, and were significantly associated with perioperative hypotension, C7-T1 disc extrusions, surgeon experience, and NSAID usage. Identification of a major postoperative AE is an indication for immediate diagnostic imaging studies, as 50% of dogs experiencing major AE required reoperation.