Chronic Abdominal Wall Pain and Ultrasound-Guided Abdominal Cutaneous Nerve Infiltration: A Case Series

Background. Chronic abdominal wall pain occurs in about 10-30% of patients presenting with chronic abdominal pain. Entrapment of abdominal cutaneous nerves at the lateral border of the rectus abdominis muscle has been attributed as a cause of abdominal wall pain. We report our experience of treating such patients using ultrasound-guided abdominal cutaneous nerve infiltration. Methods. We conducted a retrospective audit of abdominal cutaneous nerve infiltration performed in the period between September 2008 to August 2009 in our center. All patients had received local anesthetic and steroid injection under ultrasound guidance. The response to the infiltration was evaluated in the post-procedure telephone review as well as in the follow-up clinic. Brief pain inventory (BPI) and numerical rating scale pain scores were collated from two points: the initial outpatient clinic and the follow up clinic up to 5 months following the injection. Results. Nine patients had abdominal cutaneous nerve injections under ultrasound guidance in the period under review. Six patients reported 50% pain relief or more (responders) while three patients did not. Pain and BPI scores showed a decreasing trend in responders. The median duration of follow-up was 12 weeks. Conclusion. Ultrasound can reliably be used for infiltration of the abdominal cutaneous nerves. This will improve the safety as well as diagnostic utility of the procedure.