Significant factors influencing chronic postoperative inguinal pain: A conditional time-dependent observational cohort study

Background: Inguinal hernia (IH) repair is a common surgical procedure. Focus has shifted from recurrences to chronic postoperative inguinal pain (CPIP). To assess the natural course of CPIP and identify patient factors influencing the onset of CPIP, an observational registry-based study was performed. Materials and methods: Data prospectively collected from the Club-Hernie national database was retrieved from 2011 until 2021. Patients who underwent elective surgery for inguinal hernia were divided in an irrelevant pain group and relevant pain group. Relevant pain at one year and two years were compared with patients with irrelevant pain at all-time points (preoperatively, one month, one year and two years). Quality of life questions were compared between relevant pain at one year and two years. Results: 4.016 patients were included in the analysis. Mean age was 65.1 years, 90.3% of patients was male. Factors correlated with CPIP onset were age, gender, ASA, recurrent surgery, surgical technique, nerve handling and fixation type. Relevant pain at one month was a greater risk for CPIP than preoperative pain (12.3% vs 3.6%). In the majority of patients (83.2%) CPIP was ameliorated at two years. Hernia related complaints differed significantly between CPIP at one year and two years. Conclusion: Postoperative pain after one month was a greater risk factor for CPIP development than preoperative pain. CPIP at one year seems to have a different pain etiology than CPIP at two years. Patient and surgical factors influence the onset of CPIP at one year, however the natural course of these complaints shows great decline at two years, largely without reinterventions