Objective: This study aimed to evaluate the incidence of chronic groin pain (primary outcome) and alterations of sensitivity (secondary outcome) after Lichtenstein inguinal hernia repair, comparing neurectomy with ilioinguinal nerve preservation surgery. The exact cause of chronic groin postoperative pain after mesh inguinal hernia repair is usually unclear. Section of the ilioinguinal nerve (neurectomy) may reduce postoperative chronic pain.

Methods: We followed PRISMA guidelines to identify randomized studies reporting comparative outcomes of neurectomy versus ilioinguinal nerve preservation surgery during Lichtenstein hernia repairs. Studies were identified by searching in PubMed, Scopus, and Web of Science from April 2020. The protocol for this systematic review and meta-analysis was submitted and accepted from PROSPERO: CRD420201610.

Results: In this systematic review and meta-analysis, 16 RCTs were included and 1550 patients were evaluated: 756 patients underwent neurectomy (neurectomy group) vs 794 patients underwent ilioinguinal nerve preservation surgery (nerve preservation group). All included studies analyzed Lichtenstein hernia repair. The majority of the new studies and data comes from a relatively narrow geographic region; other bias of this meta-analysis is the suitability of pooling data for many of these studies. A statistically significant percentage of patients with prosthetic inguinal hernia repair had reduced groin pain at 6 months after surgery at 8.94% (38/425) in the neurectomy group versus 25.11% (113/450) in the nerve preservation group [relative risk (RR) 0.39, 95% confidence interval (CI) 0.28-0.54; Z = 5.60 (P < 0.00001)]. Neurectomy did not significantly increase the groin paresthesia 6 months after surgery at 8.5% (30/353) in the neurectomy group versus 4.5% (17/373) in the nerve preservation group [RR 1.62, 95% CI 0.94-2.80; Z = 1.74 (P = 0.08)]. At 12 months after surgery, there is no advantage of neurectomy over chronic groin pain; no significant differences were found in the 12-month postoperative groin pain rate at 9% (9/100) in the neurectomy group versus 17.85% (20/112) in the inguinal nerve preservation group [RR 0.50, 95% CI 0.24-1.05; Z = 1.83 (P = 0.07)]. One study (115 patients) reported data about paresthesia at 12 months after surgery (7.27%, 4/55 in neurectomy group vs. 5%, 3/60 in nerve preservation group) and results were not significantly different between the two groups [RR 1.45, 95% CI 0.34, 6.21;Z = 0.51 (P = 0.61)]. The subgroup analysis of the studies that identified the IIN showed a significant reduction of the 6th month evaluation of pain in both groups and confirmed the same trend in favor of neurectomy reported in the previous overall analysis: statistically significant reduction of pain 6 months after surgery at 3.79% (6/158) in the neurectomy group versus 14.6% (26/178) in the nerve preservation group [RR 0.28, 95% CI 0.13-0.63; Z = 3.10 (P = 0.002)].

Conclusion: Ilioinguinal nerve identification in Lichtenstein inguinal hernia repair is the fundamental step to reduce or avoid postoperative pain. Prophylactic ilioinguinal nerve neurectomy seems to offer some advantages concerning pain in the first 6th month postoperative period, although it might be possible that the small number of cases contributed to the insignificancy regarding paresthesia and hypoesthesia. Nowadays, prudent surgeons should discuss with patients and their families the uncertain benefits and the potential risks of neurectomy before performing the hernioplasty.