Negative-pressure wound therapy versus conventional dressings following stoma reversal: a GRADE-based systematic review and meta-analysis of randomized controlled trials with predefined subgroup analyses by closure technique

BACKGROUND: Surgical site infection (SSI) after stoma reversal remains common (15-40%), prolonging hospitalization and potentially delaying adjuvant therapy. Prophylactic negative-pressure wound therapy (NPWT) is increasingly used for closed incisions; however, its efficacy with different skin-closure techniques remains unclear. We conducted a systematic review and meta-analysis of randomized controlled trials comparing NPWT with conventional non-pressure dressings after stoma reversal, with prespecified subgroup analyses by skin-closure technique and certainty of evidence appraised using GRADE. METHODS: The review protocol was registered in the PROSPERO International Prospective Register of Systematic Reviews (CRD420251182767). We searched MEDLINE, Embase, Scopus, Web of Science, CENTRAL, ClinicalTrials.gov, and WHO ICTRP without language restrictions. Eligible randomized controlled trials enrolled adults undergoing elective ileostomy or colostomy reversal and compared negative-pressure wound therapy (NPWT) with conventional (non-pressure) dressings with a specified skin-closure technique (purse-string or primary). The primary outcome was incisional surgical site infection within 30-42 days of surgery. Secondary outcomes included length of stay, time to complete wound healing, operative duration, and estimated blood loss. Two reviewers independently screened the studies, extracted data, and assessed the risk of bias using RoB 2. Random-effects meta-analyses were conducted with sensitivity analyses and pre-specified subgroup comparisons based on closure techniques. The certainty of evidence was appraised using GRADE. RESULTS: Seven randomized trials (n = 429) met the inclusion criteria (NPWT, n = 220; conventional dressings, n = 209). The primary pooled analysis showed no significant reduction in incisional SSI with NPWT versus conventional dressings (RR 0.42, 95% CI 0.14-1.30; I²=46%). By closure technique, the effects were larger with primary closure (RR 0.20, 95% CI 0.06-0.67; I²=0%) than with purse-string closure (RR 0.68, 95% CI 0.14-3.35; I²=48%), although the interaction was not statistically significant (P = 0.23). The risk of bias was generally rated as "some concerns," primarily due to open-label care, and heterogeneity was low after the sensitivity analysis. Prespecified leave-one-out analyses identified influential studies for SSI, length of stay, and wound healing; however, these findings were interpreted as exploratory influence diagnostics and did not replace the primary pooled analyses. CONCLUSIONS: In this primary pooled analysis, prophylactic NPWT did not significantly reduce incisional surgical site infection after stoma reversal, although the effect favored NPWT. Exploratory sensitivity and subgroup analyses suggested possible benefits in selected contexts, although these findings should not supersede the nonsignificant primary pooled analyses. Larger, standardized randomized trials are needed to clarify which closure techniques and patient groups derive the greatest benefit.