Prognostic indicators of surgical outcome in painful foot drop: a systematic review and meta-analysis.

Purpose: Foot drop is a relatively uncommon presentation of lumbar degenerative disease and there is currently a paucity of evidence on management and outcomes which is reflective of the lack of standardised treatment provided to patients. The purpose of this systematic review and meta-analysis is to determine the effectiveness of surgical management and the factors that predict surgical outcome.

Methods: A systematic database search of Cochrane Library, Ovid Medline, Pubmed, Embase and Google Scholar was undertaken from inception through August 2018. Only studies reporting on surgical outcome in adult patients who had a painful foot drop and underwent decompression were included. Case reports and studies with surgical fixation were excluded. Study quality was assessed using the Newcastle-Ottawa Scale. Data were pooled using a random-effects model.

Results: 797 studies were screened and 9 observational studies met the inclusion criteria. This resulted in a total of 431 patients who underwent decompression for foot drop. Pooled rates of outcome for improvement in foot drop MRC grade were 84.5% (range 67.9-96%). Sub-group meta-analyses of studies revealed a statistically significant association between duration of foot drop (pooled 4.95 [95% CI 1.13-21.74]), severity of preoperative weakness (pooled 0.38 [95% CI 0.15-0.93]) on post-operative outcome and age (pooled 6.28 [1.33-29.72]).

Conclusion: This is the first systematic review and meta-analysis to explore the outcome and prognostic indicators of lumbar decompression for foot drop. Findings indicate that age, duration of foot drop weakness and MRC grade of foot drop prior to intervention were strong predictors of surgical outcome.