Anterior Cutaneous Nerve Entrapment Syndrome: A Common Cause of Chronic Abdominal Pain after Bariatric Surgery

Background: Unexplained abdominal pain after bariatric surgery is common and described in up to 7% of the population, leading to unnecessary opioid prescription and emergency department or outpatient clinic visits. In these patients, anterior cutaneous nerve entrapment syndrome (ACNES) can be a possible cause of the abdominal pain. ACNES is caused by local entrapment of the intercostal nerves by the anterior fascia of the abdominal wall. The aim of this study was to describe the patient characteristics, incidence, diagnostics and treatment results of ACNES in patients with a Laparoscopic Roux-en-Y gastric bypass (LRYGB) or laparoscopic sleeve gastrectomy (LSG) in their medical history. Methods: A retrospective observational cohort study was performed on patients with the diagnosis ACNES and a medical history of LRYGB or LSG, who were treated between 2015 and 2017 in a large teaching hospital. Results: A total of 34 patients were evaluated. Twenty-two out of 34 (65%) patients had a medical history of LRYGB and 12 out of 34 (35%) a LSG. The incidence of ACNES after bariatric surgery in our hospital is estimated at 2-5%. The median interval between the bariatric surgery and treatment for ACNES was 28.2 months. Lidocaine injection as treatment was effective in 32% of the patients and 68% underwent a subsequent surgical local neurectomy. The success rate after surgical neurectomy was 92%. Conclusion: ACNES is a common late complication after bariatric surgery and could be a cause of unexplained abdominal pain. Local neurectomy can be an effective treatment for this diagnosis.