Outcomes after inguinal hernia repair: how strong is the evidence for minimally invasive versus open repair?

PURPOSE: It remains controversial whether minimally invasive surgery (MIS) is superior to open surgery for inguinal hernia repair. MIS is growing in popularity, but open surgery remains more common. Consensus remains elusive even though numerous studies have been published about the topic. A new method for sensitivity analysis, the Robustness of Inferences to Replacement (RIR), can summarize the complex body of literature and evaluate the strength of the published findings to better support surgical decision-making. This study applied the RIR to the available evidence about this topic. METHODS: We reviewed studies from published meta-analyses that compared MIS versus open surgery for elective, unilateral inguinal hernia repair and calculated the RIR for each study and for the cumulative data. The RIR indicates how many patients in a published study must be replaced from a null-hypothesis population for the published result to be overturned. Higher RIRs indicate more robust conclusions. RESULTS: The literature review identified 40 randomized trials for inclusion. In the cumulative analysis, MIS had higher incidence of hernia recurrence (RIR 21), lower incidence of chronic pain (RIR 276), and lower immediate post-operative pain (RIR 1,282). CONCLUSION: The evidence supporting MIS for decreased post-operative pain and chronic pain is substantially stronger than the evidence supporting open surgery for decreased hernia recurrence. However, there is likely not a clearly superior method for all patients. The findings demonstrate how the RIR can support better surgical decision-making by helping surgeons to interpret a large and complex body of published literature.