[Persistent post-operative pain]

Abstract

Persistent post-operative pain is defined as a pain in the location of the surgery that persist for many months or even years beyond the usual course of an acute injury and is different of that suffered preoperatively. Persistent pain can be due to long lasting nociception caused by processes such as information, chronic infection or tumor. The most important causes are neuropathic pain states due to nerve compression, entrapment or other damage. Chronic pain, that is very often resistant to treatment, occurs after failed back surgery. Traumatic nerve injury during surgery results in persistent pain known as a post-surgical neuralgia. The most susceptible nerves are: intercostobrachial nerve, intervertebral nerves, ilio-hypogastric nerve, ilio-inguinal nerve, genito-femoral nerve and femoral and sciatic nerve. It means that after some, also elective, surgeries, e.g. mastectomy, thoracotomy, herniotomy, limb amputations, chelecystomy, hysterectomy and nephrectomy, persistent postoperative pain is more common than after other operations. Persistent pain can occur even in 60% patients after limb amputation, in 30% after breast tumor excicion or mastectomy, in 40% after thoracotomy and in 10-30% after hernia repair, but severe pain (NRS>5) lasting even for many years is observed in 5-10% after limb and breast amputation, thoracotomy and Post-CABG operations and in 2-4% patients after hernia repair. Modern approaches including satisfactory perioperative analgesia, nerve sparing, minimally invasive techniques, and the use of a surgical approach that minimizes tissue trauma are crucial. Following inguinal hernia repair, chronic pain is less common than after laparoscopic and mesh repairs. The prompt diagnosis of acute neuropathic pain after operation is very important and management is based on extrapolation of data from the chronic neuropathic pain setting.