Causes of chronic pain unrelated to surgical trauma after groin hernia repair: a prospective cohort study.

Background: Chronic inguinal pain (CIP) can be caused by musculoskeletal or neurological pathologies and by surgical trauma after inguinal hernia repair among other. The aim of this prospective cohort observational study was to find the incidence and causes of CIP unrelated to surgical trauma 12 months after inguinal hernia repair.

Methods: During sixteen months patients consulting a hernia center for groin-related symptoms were included in the study. Patients were evaluated by surgeons and filled out preoperatively the Inguinal Pain Questionnaires and a Numerical Rating Scale pain-questionnaire. For patients undergoing inguinal hernia repair, postoperative questionnaires similar to the pre-operative ones were sent out at 12 months. Patients scoring pain on pain questionnaires were evaluated by phone and physical examination.

Results: 289 patients (78.1%) of 370 repaired patients filled in the postoperative questionnaires. 62 (21.4%) patients scored pain, of these patients 5 (1.7%, 5/289) answered incorrectly in the pain questionnaires and 14 (4.8%, 14/289) had non-surgical trauma causes of pain: 5 musculoskeletal, 4 neurological and 3 other medical pathologies.

Conclusions: This cohort study found CIP unrelated to surgical trauma in 4.8% of patients undergoing a groin hernia repair. Most causes of pain unrelated to surgical trauma were musculoskeletal and neurological pathologies. Nearly a third of patients scoring inguinal pain on pain-questionnaires did not have chronic post-surgical pain (CPSP), therefore incidence of CPSP should not be based solely on pain questionnaires. Clinical assessment of patients with pain is necessary to excluded CIP unrelated to the surgical trauma.