Chronic pain after surgical repair of inguinal hernia

Herniotomy is one of the most frequent surgical procedures. From the literature, it can be established that chronic postoperative pain affects from 3 to 45% of patients after 3 months, mainly lightly. However, most studies are retrospective, only a few are prospective or controlled, and almost none of them provides a clear description of pain characteristics. It seems that use of local-regional anaesthesia reduces the risk of chronic postoperative pain, and that laparoscopy or herniorraphy leads to less frequent postoperative pain in the long-term. Risk factors for chronic postoperative pain comprise inguinal pain before surgery, the type of surgical procedure and intraoperative nerve damage. Quantitative and electrophysiologic studies recently showed that almost all patients exhibit impairment of genitofemoral nerve function after surgery, irrespective of the actual procedure. However, patients experiencing chronic pain exhibited a more pronounced reduction of mechanical and thermal thresholds on the operated side than pain free patients, suggesting the neuropathic nature of chronic postoperative pain. Further studies are needed to establish clearly a classification of the characteristics and causes of pain after surgical repair of inguinal hernia.