Visceral symptoms in patients with anterior cutaneous nerve entrapment syndrome (ACNES): expression of viscerosomatic reflexes?

PURPOSE: Anterior cutaneous nerve entrapment (ACNES) is characterized by neuropathic pain in a predictable, circumscript abdominal area. The diagnostic delay is long, with half of ACNES-affected individuals reporting nausea, bloating, or loss of appetite mimicking visceral disease. The aim of this study was to describe these phenomena and to determine whether treatment could successfully reverse the visceral symptoms. METHODS: This prospective observational study was conducted between July 2017 and December 2020 at SolviMáx, Center of Excellence for Chronic Abdominal Wall and Groin Pain, Máxima Medical Center, Eindhoven. Adult patients who fulfilled published criteria for ACNES and reported at least one visceral symptom at intake were eligible for the study. A self-developed Visceral Complaints ACNES Score (VICAS) questionnaire that scores several visceral symptoms (minimum 1 point, maximum 9 points) was completed before and after therapy. The success of treatment was defined as at least 50% reduction in pain. RESULTS: Data from 100 selected patients (86 females) aged 39 ± 5 years were available for analysis. Frequently reported symptoms were abdominal bloating (78%), nausea (66%) and altered defecation (50%). Successful treatment significantly reduced the number of visceral symptoms, with a VICAS before of 3 (range 1-8) and after of 1 (range 0-6) (p < 0.001). A low baseline VICAS was associated with successful treatment outcome (OR 0.738, 95% CI 0.546-0.999). CONCLUSION: Patients with ACNES may report a variety of visceral symptoms. Successful treatment substantially reduces these visceral symptoms in selected patients.

The Scratch Collapse Test in patients diagnosed with Anterior Cutaneous Nerve Entrapment Syndrome (ACNES): A report of three cases.

INTRODUCTION AND IMPORTANCE: The Scratch Collapse Test (SCT) is currently used as a supportive tool diagnosing peripheral nerve neuropathies including carpal tunnel syndrome or peroneal nerve entrapment. Some patients with chronic abdominal pain suffer from entrapment of terminal branches of intercostal nerves (anterior cutaneous nerve entrapment syndrome, ACNES). ACNES is characterized by a severe disabling pain at a predictable area of the anterior abdomen. Clinical examination shows altered skin sensation and painful pinching at the area of pain. However, these findings may be subjective. CASE PRESENTATION: In three female patients aged 71, 33, and 43 years with suspected ACNES, the SCT was positive when scratching over the skin of the affected nerve-ending at the abdominal wall. The diagnosis ACNES was confirmed with a local abdominal wall infiltration at the tenderpoint in all three patients. In case three, the SCT turned negative after lidocaine infiltration. CLINICAL DISCUSSION: ACNES was hitherto a clinical diagnosis just based on clues in medical history and physical examination. Performing a SCT in patients possibly having ACNES may additionally contribute to the diagnosis. CONCLUSION: The SCT may serve as an additional tool for diagnosing patients with possible ACNES. A positive SCT in patients with ACNES supports the hypothesis that ACNES is indeed a peripheral neuropathy of terminal branches of the lower thoracic intercostal nerves. Controlled research is necessary to confirm the role of a SCT in ACNES.

Persistent pain relief following a single injection of a local anesthetic for neuropathic abdominal wall and groin pain.

OBJECTIVES: It is our experience that a small portion of patients with neuropathic abdominal wall pain syndromes such as the anterior cutaneous nerve entrapment syndrome (ACNES) have a long term beneficial response following just one single tender point injection (TPI) with a local anesthetic agent. This report focuses on the phenomenon of ongoing pain relief following a single local anesthetic injection in neuropathic abdominal wall and groin pain syndromes. METHODS: This report is an overview based on earlier studies from a center of expertise for neuropathic abdominal wall and groin pain syndromes. All studies on neuropathic abdominal wall and groin pain syndromes reporting on efficacy of a diagnostic TPI using a local anesthetic agent were included. RESULTS: A total of 10 studies including 834 patients fulfilled study criteria. Each of these 10 studies found that approximately 10% (range, 4-25%) of the cases experienced persistent pain relief after a single TPI with lidocaine 1%. CONCLUSIONS: Persistent pain relief after a single TPI using a local anesthetic agent may be observed in approximately one of 10 patients suffering from neuropathic abdominal wall or groin pain syndromes. When a patient is suspected of having a neuropathic abdominal wall or groin pain syndrome, a single TPI using a local anesthetic agent should be administered as long term pain relief may occasionally occur.

Ultrasound-guided abdominal wall infiltration versus freehand technique in anterior cutaneous nerve entrapment syndrome (ACNES): randomized clinical trial.

BACKGROUND: The optimal technique of abdominal wall infiltration for chronic abdominal wall pain due to anterior cutaneous nerve entrapment syndrome (ACNES) is unknown. The aim of this study was to compare pain reduction after an abdominal wall anaesthetic injection by use of an ultrasound-guided technique (US) or given freehand (FH). METHODS: In this multicentre non-blinded randomized trial, adult patients with ACNES were randomized (1:1) to an US or a FH injection technique. Primary outcome was the proportion of injections achieving a minimum of 50 per cent pain reduction on the Numeric Rating Scale (range 0-10) 15-20 min after abdominal wall infiltration ('successful response'). Secondary outcomes were treatment efficacy after 6 weeks and 3 months, and the influence of the subcutaneous tissue thickness on treatment outcome. RESULTS: Between January 2018 and April 2020, 391 injections (US = 192, FH = 199) were administered in 117 randomized patients (US = 55, FH = 62; 76.0 per cent female, mean age 45 years). The proportion of successful responses did not significantly differ immediately after the injection regimen (US 27.1 per cent versus FH 33.2 per cent; P = 0.19) or after 3 months (US 29.4 per cent versus FH 30.5 per cent; P = 0.90). Success was not determined by subcutaneous tissue thickness. CONCLUSION: Pain relief following abdominal wall infiltration by a US or FH technique in ACNES is similar and not influenced by subcutaneous tissue thickness. REGISTRATION NUMBER: Dutch Clinical Trial Register NL8465.

Chronic Abdominal Pain After Previous Bariatric Surgery: Consider the Abdominal Wall.

BACKGROUND: Up to 30% of patients who undergo bariatric surgery experience recurrent abdominal pain within 3 years after the operation. Although some causes for persisting discomfort are well known, a small portion of patients may suffer from an abdominal wall pain associated with Anterior Cutaneous Nerve Entrapment Syndrome (ACNES). Aim of the present study is to discuss incidence, clinical presentation, and treatment outcome in patients with ACNES after bariatric surgery. METHODS: This retrospective observational cohort study analyzed electronically stored data of patients with ACNES having a history of bariatric surgery. All were treated for ACNES between 2011 and 2017 in a Dutch center of excellence for abdominal wall and groin pain. Success after treatment was defined as a minimal 50% drop in pain level using a Numeric Rating Scale. RESULTS: A total of 49 patients (female n = 44, median age 45 (25-63) years) were identified. Four (8%) experienced long-term pain relief after just one abdominal wall infiltration with lidocaine. Ten additional patients reported success after 2-5 injections. A total of 35 unresponsive patients chose to undergo a neurectomy that was successful in 27. Therefore, this step-up approach conferred an 84% success rate. Occurrence of ACNES after bariatric surgery was estimated at 1 in 100 patients. CONCLUSION: ACNES should be considered in the differential diagnosis of ongoing pain following previous bariatric surgery. A treatment regimen including abdominal wall infiltrations using an anesthetic agent or a neurectomy is successful in a vast majority of these patients.