Simple approach to a complex problem: Abdominal cutaneous nerve entrapment

Abstract

The aim was to show the efficacy of simple ultrasound-guided trigger point injection of local anesthetic in combination with steroid for the management of postoperative abdominal cutaneous nerve entrapment syndrome (ACNES). Abdominal cutaneous nerve entrapment can be the cause of severe, undiagnosed, abdominal pain. The entrapment of the nerve can be secondary to various conditions which cause increased abdominal pressure, leading to herniation of fat or connective tissue into the fibrous ring in the rectus abdominis muscle through which the nerve passes. Due to the compression of the nerve, there is ischemia which leads to pain. The nerve can be entrapped in scar tissue causing the compromised blood flow to the nerve and hence leading to postoperative pain. None of the available radiological investigations is helpful in diagnosing the abdominal cutaneous nerve entrapment. Clinical examination looking for tender trigger point on the abdominal wall and the eliciting a positive clinical sign, i.e., Carnett's sign can lead to the possible diagnosis of this frustrating condition. We successfully managed three cases of abdominal cutaneous nerve entrapment following laparoscopic meshplasty of abdominal hernia. All these cases were injected with a mixture of local anesthetic and steroid, i.e., 1 ml of 2% lignocaine and 1 ml of 10 mg triamcinolone at each trigger point under ultrasound guidance. The patients were prescribed pregabalin for 3 months and an anti-inflammatory COX-2 inhibitor for 10 days postprocedure. All the 3 patients were pain free at 6 months following the injections. A simple approach to a very disturbing problem of managing the severe pain due to abdominal cutaneous nerve entrapment in the postoperative period is a trigger point injection of local anesthetic and steroid under ultrasound guidance. Ultrasound-guided trigger point injections using a local anesthetic and a steroid offer an almost noninvasive option to the management of a very complex problem of ACNES.