Factors predicting outcome after anterior neurectomy in patients with chronic abdominal pain due to anterior cutaneous nerve entrapment syndrome (ACNES).

BACKGROUND: Chronic abdominal pain due to anterior cutaneous nerve entrapment syndrome may require surgery to provide long-term pain relief in up to 70% of patients. Factors predicting outcome after an anterior neurectomy are unknown. The aim of the study is to identify factors associated with treatment failure to possibly allow for optimizing patient counselling and selection. METHODS: Characteristics of anterior cutaneous nerve entrapment syndrome patients who were unresponsive to nonsurgical therapies and underwent an anterior neurectomy in a tertiary referral center from 2011 to 2016 were analyzed. Treatment failure was defined as <50% pain reduction using a numeric pain rating scale (numeric pain rating score 0-10) approximately 2 months postoperatively. A prediction model based on a multivariate regression analysis was tested for its discriminative value. RESULTS: A total of 495 patients (78% female, median age 40 years, range 8-83) undergoing an anterior neurectomy were eligible for analysis. Pain medication use (odds ratio 1.84, P = .027, confidence interval 1.07-3.17), abdominal surgery in the past (odds ratio 1.85, P = .026, confidence interval 1.08-3.18), the presence of paravertebral tender points at exit points of intercostal nerves (odds ratio 2.58, P = .003, confidence interval 1.39-4.80), and failure to favorably respond to a diagnostic rectus sheath block (odds ratio 3.74, P = .000, confidence interval 3.74 - 7.10) were identified as factors predicting surgical failure. However, a prediction model including these 4 factors had poor accuracy with an area under the curve of 0.64 (confidence interval 0.58-0.70). CONCLUSION: The present study identified risk factors associated with treatment failure that are useful in counseling anterior cutaneous nerve entrapment syndrome patients prior to a surgical intervention.