RESUMO
INTRODUCTION: The EHS clinical guidelines recommend the use of mesh to repair symptomatic primary inguinal hernias (PIH) in adult males but, in spite of this, it begs the question as to why there is still place for tissue techniques. Lack of stratification of patients according to risk of recurrence in RCTs might be a cause of results disparity, since medial and mixed are hernias with higher risk of recurrence (HRRH), whereas lateral hernias present a lower risk (LRRH). OBJECTIVE: To determine whether the lack of stratification may lead to questionable conclusions regarding the protective effect of mesh techniques and to identify other methodological flaws. METHODS: In the RCTs included in the clinical guidelines that addressed recurrences of PIH after mesh and non-mesh techniques, we assessed the type of hernias classification used, the number needed to treat in LRRH and HRRH and the statistical power. RESULTS: Most of trials were underpowered; five studies classified the hernia types; in the three studies that compared the recurrence rates of LRRH and HRRH the effect of mesh techniques was small; only two trials record data needed to calculate the NNT in LRRH (46 y 84 patients, respectively). CONCLUSION: The idea that mesh techniques reduce the recurrence rate in all PIHs is not supported by high level of evidence. The NNT for pure lateral hernias was very high and should be interpreted taking into account chronic pain rates and costs.