Persistent neuropathic pain after inguinal herniorrhaphy depending on the procedure (open mesh v. laparoscopy): a propensity-matched analysis.

Background: A greater incidence of persistent pain after inguinal herniorrhaphy is suspected with the open mesh procedure than with laparoscopy (transabdominal preperitoneal), but the involvement of neuropathy needs to be clarified.
Methods: We examined the cumulative incidence of neuropathic persistent pain, defined as self-report of pain at the surgical site with neuropathic aspects, within 6 months after surgery in 2 prospective subcohorts of a multicentre study. We compared open mesh with laparoscopy using different analysis, including a propensity-matched analysis with the propensity score built from a multivariable analysis using a generalized linear model.
Results: Considering the full patient sample (242 open mesh v. 126 laparoscopy), the raw odds ratio for neuropathic persistent pain after inguinal herniorrhaphy was 4.3. It reached 6.8 with the propensity-matched analysis conducted on pooled subgroups of 194 patients undergoing open mesh and 125 undergoing laparoscopy (95% confidence interval 1.5-30.4, p = 0.012). A risk factor analysis of these pooled subgroups revealed that history of peripheral neuropathy was an independent risk factor for persistent neuropathic pain, while older age was protective.
Conclusion: We found a greater risk of persistent pain with open mesh than with laparoscopy that may be explained by direct or indirect lesion of nerve terminations. Strategies to identify and preserve nerve terminations with the open mesh procedure are needed.