Intraneural fibrosis within ilioinguinal nerve in inguinal hernia patients with preoperative pain -It’s the sign of irreversible nerve injury, isn’t it?

Abstract

Purpose Preoperative pain is known as the most powerful risk factor for chronic postoperative inguinal pain (CPIP), while its pathogenesis has not been fully elucidated. The aim of the present study was to evaluate patients with preoperative pain from the pathological perspective and discuss the potential pathogenesis of CPIP in those patients. Methods This was a single-institutional retrospective study. The study population was inguinal hernia patients with preoperative pain who underwent open anterior hernia repair for primary inguinal hernia with pragmatic ilioinguinal neurectomy during surgery between March 2021 and March 2023. The primary and secondary outcomes were proportion of collagen deposition and mucus accumulation within ilioinguinal nerve in those patients, respectively, which were evaluated histologically using Image J software. Results Forty patients were evaluated. Median value of proportion of intraneural collagen deposition was 38.3 (27.7-95.9) %. These values were positively correlated with the duration of pain (r2=0.468, P<0.001). Median value of proportion of mucus accumulation in ilioinguinal nerve was 50.1 (0-82.0) %. These values had no correlation with any clinicopathological variables. Conclusions In the present study population, all patients with preoperative pain had intraneural fibrosis within ilioinguinal nerve, and its degree had a significantly positive correlation with the pain duration. These results suggest that nerve injury may be irreversible and open anterior hernia repair with a planned ilioinguinal neurectomy may be a good option for patients with long-term preoperative pain to prevent persistent pain that being present preoperatively.