Background: Surgical strategy regarding nerve identification and resection in relation to chronic postoperative pain remains controversial. A central question is whether nerves in the operation field, when identified, should be preserved or resected. In the present study, the hypotheses that the identification and consequent resection of nerves 'at risk' have no influence on postoperative pain has been tested.
Methods: A single-centre study was conducted in 525 patients undergoing Lichtenstein hernioplasty. One surgeon (364 operations, Group A) consequently resected nerves 'at risk' for being injured and nine surgeons (161 operations, Group B) adhered to the general routine of nerve preservation. All cases were ambulatory surgery on anaesthetised patients and the groups were similar with regard to age, body mass index (BMI) and preoperative pain. Self-reported pain at 3 months was recorded on a 10-box visual analogue scale (VAS). The identification and resection of nerves were continuously registered. Statistical calculations were performed with Fisher's exact test and ordinal logistic regression.
Results: There was no significant difference in the number of identified nerves in the two groups of patients (iliohypogastricus, P = 0.555; ilioinguinalis, P = 0.831; genital branch, P = 0.214). However, the number of resected nerves was significantly higher in Group A for the iliohypogastric nerve, P < 0.001, but not for ilioinguinalis, P = 0.064, and genital branch, P = 0.362. Non-identification of the ilioinguinal nerve correlated to the highest level of self-reported postoperative pain at 3 months. Patients in Group A, who had nerves 'at risk' resected from the operation field, reported significantly less postoperative pain at 3 months, P = 0.007.
Conclusion: This register study confirms the importance of nerve identification. Nerve resection strategy with the consequent removal of nerves 'at risk' gives a significantly better outcome in Lichtenstein hernioplasty.