EXPRESS: Feline intervertebral disc disease – a systematic review and meta-analysis

Objectives: Feline intervertebral disc disease (IVDD), historically an uncommonly described problem, is being increasingly documented in the current literature. The objective of this systematic review is to consolidate existing knowledge of feline IVDD, identify possible prognostic factors and assist by offering clearer guidelines when managing a feline spinal patient. Methods: A systematic search of two databases was conducted using keywords related to feline IVDD. Studies with cats diagnosed with IVDD, including treatment and outcome details, were reviewed. Prognostic factors were evaluated for their impact on overall outcomes. Results: A total of 57 studies with 1113 cats were identified, after the reviewing process, 23 studies with 93 cats remained for statistical analysis. Most cats (59%) had lumbar spine involvement, followed by thoracolumbar (31%) and cervical (5%) segments. Intervertebral disc extrusion (IVDE) was the most common diagnosis (65/93), followed by intervertebral disc protrusion (IVDP) (16/93) and acute non-compressive nucleus pulposus extrusion (ANNPE) (12/93). Deep pain perception was preserved in 87% of cats. Surgical intervention was performed in 75/93 cats while 17/93 were treated conservatively, 1/93 being euthanized intraoperatively. Overall, 85% of cats had a positive outcome, 11% had a negative outcome, and outcomes were undetermined in 4% of cases. Possible influencing factors analyzed included the breed, sex, age (in years and life stage), weight, affected spinal segment, number of affected discs, micturition status, treatment choice, deep pain perception and IVDD type. No statistically significant prognostic factors (p>0.05) were identified. Conclusion and relevance: Although no specific prognostic factors could be identified, the systematic review suggests that feline IVDD has a predominantly positive prognosis regardless of treatment choice. Given the low evidence level and small sample size, further multicenter, prospective studies with larger cohorts are required to establish reliable prognostic factors for feline IVDD.