Diathermy versus scalpel for skin incision in patients undergoing open inguinal hernia repair: A systematic review and meta-analysis

Objectives: To compare outcomes of diathermy and scalpel for skin incision in patients undergoing open inguinal hernia repair. Methods: We performed a systematic review in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement standards. We conducted a search of electronic information sources to identify all randomised controlled trials (RCTs) and observational studies comparing use of diathermy and scalpel for skin incision in patients undergoing inguinal hernia repair. Surgical site infection (SSI) was the primary outcome measure. Secondary outcome measures included haematoma, seroma, visual analogue scale (VAS) pain score at 6 h, 12 h, and 24 h, and incision time. We used Cochrane risk of bias tool and ROBINS-I tool to assess the risk of bias of randomised and non-randomised studies. Fixed-effect model was applied to calculate pooled outcome data. Results: We identified 9 studies, 4 randomised controlled trials and 5 prospective cohort studies, enrolling a total of 830 patients. Meta-analysis of RCTs showed no difference between the diathermy and scalpel groups in terms of surgical site infection (OR: 0.77, 95% CI 0.34, 1.75, P = 0.53), seroma (OR: 0.86, 95% CI 0.29, 2.55, P = 0.78), VAS pain score at 6 h (MD: -0.10, 95% CI -0.31, 0.11, P = 0.34), 12 h (MD: -0.10, 95% CI -0.13, 0.33, P = 0.40), and 24 h (MD: 0.03, 95% CI -0.16, 0.21, P = 0.79). Use of diathermy for skin incision was associated with shorter incision time (MD: -36.00, 95% CI -47.92, -24.08, P < 0.00001) and lower risk of haematoma (OR: 0.14, 95% CI 0.03, 0.65, P = 0.01). Meta-analysis of observational studies showed no difference between the diathermy and scalpel groups in terms of surgical site infection (OR: 0.87, 95% CI 0.54, 1.39, P = 0.55), haematoma (OR 0.14, 95% CI 0.02-1.23, P = 0.08), seroma (OR: 0.86, 95% CI 0.29, 2.55, P = 0.78), VAS pain score at 6 h (MD: -0.10, 95% CI -0.44, 0.24, P = 0.56), 12 h (MD: -0.10, 95% CI -0.26, 0.46, P = 0.58), and 24 h (MD: 0.10, 95% CI -0.27, 0.47, P = 0.59). Use of diathermy for skin incision was associated with shorter incision time (MD: -39.40, 95% CI -41.02, -37.78, P < 0.00001). The results remained consistent through sensitivity analyses. The between-study heterogeneity was low and the quality of the available evidence was moderate. Conclusions: There is no difference between use of diathermy and scalpel for skin incision in patients undergoing open inguinal hernia repair in terms of surgical site infection, seroma and postoperative pain. Use of diathermy for skin incision may be associated with shorter incision time and may reduce the risk of haematoma formation.