Mesh versus non-mesh for emergency groin hernia repair

Background A groin hernia is a collective name for inguinal and femoral hernias, which can present acutely with incarceration or strangulation of the hernia sac content, requiring emergency treatment. Timely repair of emergency groin hernias is crucial due to the risk of reduced blood supply and thus damage to the bowel, but the optimal surgical approach is unclear. While mesh repair is the standard treatment for elective hernia surgery, using mesh for emergency groin hernia repair remains controversial due to the risk of surgical site infection. Objectives To assess the benefits and harms of mesh compared with non‐mesh in emergency groin hernia repair in adult patients with an inguinal or femoral hernia. Search methods On 5 August 2022, we searched the following databases: CENTRAL, MEDLINE Ovid, and Embase Ovid, as well as two trial registers for ongoing and completed trials. Additionally, we performed forward and backward citation searches for the included trials and relevant review articles. We searched without any language or publication restrictions. Selection criteria We included randomised controlled trials (RCTs) comparing mesh with non‐mesh repair in emergency groin hernia surgery in adults. We included any mesh and any non‐mesh repairs. All studies fulfilling the study, participant, and intervention criteria were included irrespective of reported outcomes. Data collection and analysis We used standard Cochrane methodology. We presented dichotomous data as risk ratios (RR) with 95% confidence intervals (CI). We based missing data analysis on best‐ and worst‐case scenarios. For outcomes with sufficiently low heterogeneity, we performed meta‐analyses using the random‐effects model. We analysed subgroups when feasible, including the degree of contamination. We used RoB 2 for risk of bias assessment, and summarised the certainty of evidence using GRADE. Main results We included 15 trials randomising 1241 participants undergoing emergency groin hernia surgery with either mesh (626 participants) or non‐mesh hernia repair (615 participants). The studies were conducted in China, the Middle East, and South Asia. Most patients were men, and most participants had an inguinal hernia (41 participants had femoral hernias). The mean/median age in the mesh group ranged from 35 to 70 years, and from 41 to 69 years in the non‐mesh group. All studies were performed in a hospital emergency setting (tertiary care) and lasted for 11 to 139 months, with a median study duration of 31 months. The majority of the studies only included participants with clean to clean‐contaminated surgical fields. For all outcomes, we considered the certainty of the evidence to be very low, mainly downgraded due to high risk of bias (due to deviations from intended intervention and missing outcome data), indirectness, and imprecision. Mesh hernia repair may have no effect on or slightly increase the risk of 30‐day surgical site infections (RR 1.66, 95% CI 0.96 to 2.88; I² = 21%; 2 studies, 454 participants) when compared with non‐mesh hernia repair, but the evidence is very uncertain. The evidence is also very uncertain about the effect of mesh hernia repair compared with non‐mesh hernia repair on 30‐day mortality (RR 1.38, 95% CI 0.58 to 3.28; 1 study, 208 participants). In summary, the results showed 70 more (from 5 fewer to 200 more) surgical site infections and 29 more (from 32 fewer to 175 more) deaths within 30 days of mesh hernia repair per 1000 participants compared with non‐mesh hernia repair. The evidence is very uncertain about 90‐day surgical site infections after mesh versus non‐mesh hernia repair (RR 1.00, 95% CI 0.15 to 6.64; 1 study, 60 participants; very low‐certainty evidence). No 30‐day recurrences were recorded, and mesh hernia repair may not reduce recurrence within one year (RR 0.19, 95% CI 0.04 to 1.03; I² = 0%; 2 studies, 104 participants; very low‐certainty evidence). Within 30 days of hernia repair, no meshes were removed from clean to clean‐contaminated fields, but 6.7% of meshes (1 study, 208 participants) were removed from contaminated to dirty surgical fields. Among the four studies reporting 90‐day mesh removal, no events occurred. We were not able to identify any studies reporting complications classified according to the Clavien‐Dindo Classification or reoperation for complications within 30 days of repair. Authors' conclusions Our results show that in terms of 30‐day surgical site infections, 30‐day mortality, and hernia recurrence within one year, the evidence for the use of mesh hernia repair compared with non‐mesh hernia repair in emergency groin hernia surgery is very uncertain. Unfortunately, firm conclusions cannot be drawn due to very low‐certainty evidence and meta‐analyses based on small‐sized and low‐quality studies. There is a need for future high‐quality RCTs or high‐quality registry‐based studies if RCTs are unfeasible.