Retromuscular (sublay) synthetic mesh reinforcement versus no mesh at end-colostomy creation to prevent parastomal hernia: a GRADE-assessed systematic review and meta-analysis of randomized controlled trials featuring subgroup analysis by CT-mandated

Parastomal hernia is a major complication following end-colostomy, affecting 30–70% of patients and imposing significant healthcare burdens. Prophylactic mesh reinforcement has emerged as a preventive strategy; however, evidence synthesis has been limited by methodological heterogeneity across diverse anatomical approaches to hernia repair. This GRADE-assessed systematic review and meta-analysis was prospectively registered in the PROSPERO database (ID: CRD420251143346). We searched MEDLINE, Embase, Cochrane CENTRAL, Scopus, Web of Science, ClinicalTrials.gov, and WHO ICTRP until August 2025 for randomized controlled trials comparing retromuscular synthetic mesh reinforcement versus no mesh during end colostomy creation. The primary outcomes were clinical parastomal hernias and safety parameters. Random-effects meta-analyses were performed, and comprehensive sensitivity and subgroup analyses were included. Seven randomized trials (956 patients) were included in this meta-analysis. Prophylactic retromuscular mesh reduced clinical parastomal hernia rates (OR 0.44, 95% CI 0.22–0.89; P = 0.02), although heterogeneity was substantial (I²=73%). The control group parastomal hernia rate was 312 per 1,000 patients; prophylactic mesh reduced this to 213 per 1,000 (99 fewer hernias per 1,000 patients; 95% CI 28–213 fewer). However, in the leave-one-out analysis, the reduction in clinical parastomal hernia was no longer statistically significant after exclusion of one influential trial (OR 0.58, 95% CI 0.31–1.10), indicating that the pooled estimate was sensitive to study selection. Safety outcomes showed no significant differences in the incidence of composite complications (OR 1.15, 95% CI 0.84–1.59), stoma necrosis (OR 0.79, 95% CI 0.31–2.07), reoperation (OR 0.88, 95% CI 0.52–1.48), or surgical site infection (OR 0.94, 95% CI 0.57–1.55). Operative time (MD + 8.52 min, 95% CI − 8.38 to + 25.42) and hospital stay (MD + 3.69 days, 95% CI − 1.52 to + 8.90) also showed no significant differences. The certainty of evidence for the primary outcome was low because of substantial inconsistency, indicating limited confidence in the precision and robustness of the effect estimates. This GRADE-assessed systematic review and meta-analysis suggests that prophylactic retromuscular synthetic mesh may reduce clinically detected parastomal hernia after end-colostomy creation; however, the certainty of this benefit remains low because the pooled signal was heterogeneous, attenuated in trials using standardized CT-based assessment, and sensitive to individual-study removal. These findings support cautious and selective use rather than routine universal implementation.