Postoperative drainage after totally extra-peritoneal inguinal hernia repair: systematic review and meta-analysis

<b>Introduction:</b> Total extra-peritoneal (TEP) repair is one of minimally invasive treatment options for inguinal hernia repair. While TEP repair has several advantages over other minimally invasive techniques, the main drawback of TEP is higher incidence of seroma formation. The goal of our study was to systematically review and meta analyze existing evidence on the role of postoperative drainage post TEP surgery for groin hernia repair and to assess risks associated with use of drains. <br><br><b>Aim:</b> The goal of our study was to systematically review and meta-analyse the existing evidence on the role of postoperative drainage post TEP surgery for groin hernia repair and to assess risks associated with the use of drains. <br><br><b>Methods:</b> A systematic literature search of major databases was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines to identify studies that compared usage of drain with control in patients undergoing TEP. Primary outcomes for this study were: seroma rates, surgical site infection rates (SSI), urinary retention, postoperative pain at 24 hours after operation, postoperative pain at one week after operation, chronic pain and quality of life scores (QoL). Random-effects and Fixed-effects models to analyse data were used. Risk difference (RD) was calculated for dichotomous outcomes (seroma, SSI, urinary retention) with 95% confidence intervals (CI). Statistical heterogeneity was assessed using the I2 test. Risk of bias was assessed using the Newcastle-Ottawa scale for observational studies and Risk of Bias Tool -2 for randomised controlled trials (RCTs).<br><br><b>Results:</b> There were 5 studies that enrolled 1659 participants (1288 in the drain group and 371 in the control group). Three studies were observational and two were RCTs. The meta-analysis of included studies has confirmed significant risk difference in the occurrence of seroma in favour of using postoperative drain (RD -0.19 [-0.26, -0.12], test for overall effect: Z = 5.24 (p<0.00001), I² = 59%). There was significant clinical and statistical heterogeneity in findings. <br><br><b>Conclusions:</b> Use of postoperative drains after TEP is safe and was shown to be associated with a reduced risk of seroma formation, although a low number of studies was included with a predominance of observational data. There was significant clinical and statistical heterogeneity in findings.