Groin anatomy, preoperative pain, and compression neuropathy in primary inguinal hernia: What really matters.

INTRODUCTION: Enlargement of the ilioinguinal nerve distal to the inguinal ring is common in primary open inguinal herniorrhaphy and is histologically consistent with compression neuropathy. However, the origin of this neuropathy has not been thoroughly studied in primary inguinal hernia.

METHODS: In this prospective study, 143 primary inguinal herniorrhaphies were performed. Prior to surgery, all patients completed a preoperative pain questionnaire from the Carolina Comfort Scale and Visual Analog Scale-evaluating pain with various activities. Pain scores were statistically compared with several different anatomical surgical observations.

RESULTS: When each variable is individually compared with pain scores, a significant positive correlation exists between nerve enlargement and increased pain compared to those without enlargement for preoperative "most of the time pain" (P < 0.0017). There is also a statistically significant positive correlation between nerve enlargement and external ring fibrosis (P < 0.001). 81% of patients with enlargement have histological abnormalities.

CONCLUSION: Preoperative pain in primary inguinal hernia is correlated with ilioinguinal nerve enlargement, which is also correlated with fibrosis of the external oblique fascia at the external ring.