A systematic review and meta-analysis of wound drains in non-instrumented lumbar decompression surgery

Wound drains are routinely used in lumbar decompressive surgery (LDS). However, it remains unclear whether this practice helps to prevent symptomatic epidural hematoma formation and associated complications, particularly following non-instrumented procedures. A systematic review and meta-analysis was therefore completed to critically appraise the literature. The search protocol was conducted using the Ovid MEDLINE, EMBASE, Scopus, Cochrane Library, and Google Scholar databases. Articles meeting the following criteria were included: (i) examined patients undergoing LDS; (ii) included cases receiving post-operative wound drains; (iii) detailed adverse outcomes including symptomatic epidural hematomas or wound infection; and (iv) were published in English in a peer-reviewed journal. Pooled risk differences (RD) for adverse outcomes were calculated using Comprehensive Meta-Analysis software. Three Level 1b prospective randomized studies and five Level 2b retrospective cohort studies were included, from which 5,327 cases were identified as having received a surgical drain and 773 were identified as having received no drainage following non-instrumented LDS. There was no difference between groups in the risk of symptomatic epidural hematoma (RD = 0.02; 95% CI -0.02 - 0.06, p = 0.28) or post-operative infection (RD = 0.00; 95% CI -0.01 - 0.01, p = 0.91). In conclusion, symptomatic epidural hematomas and infection are rare following non-instrumented LDS, with incidence rates unaffected by the routine use of wound drainage.