Surgical options after a failed neurectomy in anterior cutaneous nerve entrapment syndrome

Groin Pain Syndrome Italian Consensus Conference update 2023

Groin pain syndrome (GPS) is a controversial topic in Sports Medicine. The GPS Italian Consensus Conference on terminology, clinical evaluation and imaging assessment of groin pain in athletes was organized by the Italian Society of Arthroscopy in Milan, on 5 February 2016. In this Consensus Conference (CC) GPS etiology was divided into 11 different categories for a total of 63 pathologies. The GPS Italian Consensus Conference update 2023 is an update of the 2016 CC. The CC was based on a sequential, two-round online Delphi survey, followed by a final CC in the presence of all panelists. The panel was composed of 55 experts from different scientific and clinical backgrounds. Each expert discussed 6 different documents, one of which regarded the clinical and imaging definition of sports hernias, and the other 5 dealt with 5 new clinical situations thought to result in GPS. The panelists came to an agreement on the definition of a sports hernia. Furthermore, an agreement was reached, recognizing 4 of the 5 possible proposed pathologies as causes to GPS. On the contrary, the sixth pathology discussed did not find consensus given the insufficient evidence in the available scientific literature. The final document includes a new clinical and imaging definition of sports hernia. Furthermore, the etiology of GPS was updated compared to the previous CC of 2016. The new taxonomic classification includes 12 categories (versus 11 in the previous CC) and 67 pathologies (versus 63 in the previous CC).

Three Subtypes of Cutaneous Nerve Entrapment Syndrome: A Narrative Review

Anterior, lateral, and posterior cutaneous nerve entrapment syndromes have been proposed as etiologies of trunk pain. However, while these syndromes are analogous, comprehensive reports contrasting the three subtypes are lacking. We therefore reviewed the literature on anterior, lateral, and posterior cutaneous nerve entrapment syndrome. We searched the PubMed and Cochrane Library databases twice for relevant articles published between March and September 2022. In addition to 16 letters, technical reports, and review articles, a further 62, 6, and 3 articles concerning anterior, lateral, and posterior cutaneous nerve entrapment syndromes, respectively, were included. These syndromes are usually diagnosed based solely on unique history and examination findings; however, the diagnostic process may be prolonged, and multiple re-evaluations are required. The most common first-line treatment is trigger point injection; however, the management of refractory cases remains unclear. Awareness of this disease should be expanded to medical departments other than general medicine.

Laparoscopic Surgical Options as a Minimally Invasive Procedure for a Patient With Recurrent Postoperative Pain in Anterior Cutaneous Nerve Entrapment Syndrome: A Case Report

This report presents a case of a 70-year-old woman who developed anterior cutaneous nerve entrapment syndrome (ACNES) three years ago and had an anterior cutaneous neurectomy in the left Th10 region. Postoperatively, the pain had improved entirely, but 10 weeks later, she developed a recurrence in the vicinity of the wound. The anterior intercostal nerve branch (Th10), located between the transversus abdominis and internal oblique muscles, was dissected laparoscopically six months after the initial surgery. There was no re-recurrence of pain for four months postoperatively. The postoperative recurrence of ACNES was refractory to various treatments, including surgical neurectomy, and is often difficult to treat. In cases in which transversus abdominis plane block is effective, laparoscopic neurectomy through an intraperitoneal approach may be effective, and minimally invasive laparoscopic treatment may be an effective surgical option for patients with recurrent and refractory ACNES who have a low pain threshold and are prone to prolonged complaints due to wound pain.

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.

Nerve Identification Procedures Are Necessary for Complete Recovery From Recurrent Cases of Anterior Cutaneous Nerve Entrapment Syndrome: A Case Report

Anterior cutaneous nerve entrapment syndrome (ACNES) involves pain in the abdominal wall due to nerve compression or ischemia. The diagnosis of ACNES is challenging with the pain often inclined to be diagnosed as psychological in origin. A 20-year-old woman presenting with abdominal pain was initially diagnosed with mesenteric lymphadenitis and prescribed pain relievers. However, following worsened pain, she was hospitalized. Blood examinations, abdominal and gynecological ultrasonography, and gastrocolonoscopy yielded no abnormal findings, leading to suspicions of psychological factors. As the patient experienced sharp abdominal pain on movement, but not at rest, which was temporarily relieved by lidocaine injections, she was diagnosed with ACNES. Rectus abdominal resection was performed but the pain relapsed. Laparoscopic surgery was performed to cut the nerve that caused the pain. After three surgeries, the patient was completely symptom-free. ACNES should be considered as a differential diagnosis for intractable abdominal pain. For recurrent relapses, the triggering nerves must be carefully identified for the successful treatment of ACNES.

Surgical Management of Abdominal Anterior Cutaneous Nerve Entrapment Syndrome: Case Report, Surgical Technique, and Literature Review

Background:

Abdominal anterior cutaneous nerve entrapment syndrome (ACNES) is an emerging diagnosis, with estimated incidence of 13%–30% of the adult population. It is a syndrome characterized by chronic abdominal pain caused by entrapment of cutaneous branches of thoracoabdominal nerves at the lateral border of the rectus abdominis muscle. If conservative treatment with pain medication, botulinum toxin, or lidocaine injections is inadequate, surgical management is indicated.

Methods:

We present a case of a 40-year-old woman presenting with a 1-year history of daily right anterior abdominal wall pain, consistent with a diagnosis of ACNES. We describe our approach for an anterior neurectomy of the intercostal nerve with closure of its fascial foramen.

Results:

Three months after surgery, she remained pain free and was back to work full time. At a 13-month follow-up, the patient reported that her pain had resolved completely following surgery.

Conclusions:

Results are encouraging following anterior neurectomy for ACNES. Surgical descriptions in the literature are brief, with limited pictorial account. Our detailed surgical approach is provided along with a review of the existing literature on the management of ACNES.

Treatment strategies for anterior cutaneous nerve entrapment syndrome in children: A systematic review

BACKGROUND

Anterior cutaneous nerve entrapment syndrome (ACNES) is a frequently overlooked cause of chronic abdominal pain in children. Currently, both nonsurgical and surgical treatment options are available to treat this disease. The objective was to give insight into the success rate of different treatment strategies for children with ACNES, and provide treatment recommendations for physicians based on the published evidence.

METHOD

A literature search of PubMed, Embase.com and the Wiley/Cochrane Library was conducted for studies published up to 25 February 2020. Randomized controlled trials, prospective or retrospective cohort studies, meta-analyses and literature reviews describing the outcome of different treatment strategies for children (<18 years old) with ACNES with a follow-up duration of at least four weeks were included.

RESULTS

Six studies, involving 224 patients, were included with an overall quality reported to be between fair and poor. Treatment success of local injections with an anesthetic agent into the trigger point ranged from 38% to 87% with a follow-up ranging from 4 weeks to 39 months. In addition, treatment success of anterior neurectomy ranged from 86% to 100%, with a follow-up duration ranging from 4 weeks to 36 months.

CONCLUSION

A step-up treatment strategy should be applied when treating pediatric patients with ACNES. This strategy starts with an injection with a local anesthetic agent, reserving surgery (anterior neurectomy) as a viable option in case of persistent pain.

LEVEL OF EVIDENCE

II.

Abdominal Wall Pain: A Common Clinical Problem

Abdominal wall pain (AWP) is a common and underrecognized cause of chronic abdominal pain. The etiology of AWP varies. History and physical examination are critical to an accurate diagnosis of AWP. Trigger point injection using either a corticosteroid, a local anesthetic, or a combination of both often gives relief of pain and is of diagnostic and therapeutic value. Increased awareness of AWP as a cause of chronic, nonvisceral abdominal pain can prevent fruitless searches for intra-abdominal pathology and reduce medical costs.

Pulsed Radiofrequency as a Minimally Invasive Treatment Option in Anterior Cutaneous Nerve Entrapment Syndrome: A Retrospective Analysis of 26 Patients

BACKGROUND

Chronic abdominal pain is occasionally due to entrapped intercostal nerve endings (ACNES, abdominal cutaneous nerve entrapment syndrome). If abdominal wall infiltration using an anesthetic agent is unsuccessful, a neurectomy may be considered. Pulsed radiofrequency (PRF) is a relatively new treatment option for various chronic pain syndromes. Evidence regarding a beneficial effect of this minimally invasive technique in ACNES is lacking. The aim was to assess the effectiveness of PRF treatment in ACNES patients.

METHODS

A series of ACNES patients undergoing PRF treatment between January 2014 and December 2015 in two hospitals were retrospectively evaluated. Pain was recorded prior to treatment and after 6 weeks using a numerical rating scale (NRS, 0 (no pain) to 10 (worst possible pain)). Successful treatment was defined as > 50% NRS pain reduction. Patient satisfaction was scored by patient global impression of change (PGIC, 1 = very much worse, to 7 = very much improved).

RESULTS

Twenty-six patients were studied (17 women, median age 47 years, range 18 - 67 years). After 6 weeks, mean NRS score had dropped from 6.7 ± 1.2 to 3.8 ± 2.3 (P < 0.001). A mean 4.9 ± 1.4 PGIC score was reported by then. Short term treatment success (6 - 8 weeks) was 50% (n = 13, 95% CI: 29 - 71), while 8% was pain-free on the longer term (median 15 months). Median effect duration was 4 months (range 2 - 26).

CONCLUSIONS

PRF is temporarily effective in half of patients with ACNES. PRF is safe and may be favored in neuropathic pain syndromes as nerve tissue destruction is possibly limited. A randomized controlled trial determining the potential additional role of PRF in the treatment strategy for ACNES is underway.

Pulsed radiofrequency or anterior neurectomy for anterior cutaneous nerve entrapment syndrome (ACNES) (the PULSE trial): study protocol of a randomized controlled trial

Background

Some patients with chronic abdominal pain suffer from an anterior cutaneous nerve entrapment syndrome (ACNES). This somewhat illusive syndrome is thought to be caused by the entrapment of end branches of the intercostal nerves residing in the abdominal wall. If ACNES is suspected, a local injection of an anesthetic agent may offer relief. If pain is recurrent following multiple-injection therapy, an anterior neurectomy entailing removal of the entrapped nerve endings may be considered. After 1 year, a 70% success rate has been reported. Research on minimally invasive alternative treatments is scarce. Pulsed radiofrequency (PRF) treatment is a relatively new treatment for chronic pain syndromes. An electromagnetic field is applied around the nerve in the hope of leading to pain relief. This randomized controlled trial compares the effect of PRF treatment and neurectomy in patients with ACNES.

Methods

Adult ACNES patients having short-lived success following injections are randomized to PRF or neurectomy. At the 8-week follow-up visit, unsuccessful PRF patients are allowed to cross over to a neurectomy. Primary outcome is pain relief after either therapy. Secondary outcomes include patient satisfaction, quality of life, use of analgesics and unanticipated adverse events. The study is terminated 6 months after receiving the final procedure.

Discussion

Since academic literature on minimally invasive techniques is lacking, well-designed trials are needed to optimize results of treatment for ACNES. This is the first large, randomized controlled, proof-of-concept trial comparing two therapy techniques in ACNES patients. The first patient was included in October 2015. The expected trial deadline is December 2017. If effective, PRF may be incorporated into the ACNES treatment algorithm, thus minimizing the number of patients requiring surgery.

Trial registration

Nederlands Trial Register (Dutch Trial Register), NTR5131 (http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=5131). Registered on 15 April 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2110-5) contains supplementary material, which is available to authorized users.

Chronic Abdominal Wall Pain

BACKGROUND

Chronic abdominal wall pain is a poorly recognized clinical problem despite being an important element in the differential diagnosis of abdominal pain.

METHODS

This review is based on pertinent articles that were retrieved by a selective search in PubMed and EMBASE employing the terms "abdominal wall pain" and "cutaneous nerve entrapment syndrome," as well as on the authors' clinical experience.

RESULTS

In 2% to 3% of patients with chronic abdominal pain, the pain arises from the abdominal wall; in patients with previously diagnosed chronic abdominal pain who have no demonstrable pathological abnormality, this likelihood can rise as high as 30% . There have only been a small number of clinical trials of treatment for this condition. The diagnosis is made on clinical grounds, with the aid of Carnett's test. The characteristic clinical feature is strictly localized pain in the anterior abdominal wall, which is often mischaracterized as a "functional" complaint. In one study, injection of local anesthesia combined with steroids into the painful area was found to relieve pain for 4 weeks in 95% of patients. The injection of lidocaine alone brought about improvement in 83-91% of patients. Long-term pain relief ensued after a single lidocaine injection in 20-30% of patients, after repeated injections in 40-50% , and after combined lidocaine and steroid injections in up to 80% . Pain that persists despite these treatments can be treated with surgery (neurectomy).

CONCLUSION

Chronic abdominal wall pain is easily diagnosed on physical examination and can often be rapidly treated. Any physician treating patients with abdominal pain should be aware of this condition. Further comparative treatment trials will be needed before a validated treatment algorithm can be established.

Anterior cutaneous nerve entrapment syndrome: management challenges

Anterior cutaneous nerve entrapment syndrome (ACNES) is a commonly underdiagnosed and undertreated chronic state of pain. This syndrome is characterized by the entrapment of the cutaneous branches of the lower thoracoabdominal intercostal nerves at the lateral border of the rectus abdominis muscle, which causes severe, often refractory, chronic pain. This narrative review aims to identify the possible therapeutic strategies for the management of the syndrome. Seventeen studies about ACNES therapy were reviewed; of them, 15 were case-control studies, case series, or case reports, and two were randomized controlled trials. The presently available management strategies for ACNES include trigger point injections (diagnostic and therapeutic), ultrasound-guided blocks, chemical neurolysis, and surgical neurectomy, in combination with systemic medication, as well as some emerging techniques, such as radiofrequency ablation and neuromodulation. An increased awareness of the syndrome and the use of specific diagnostic criteria for its recognition are required to facilitate an early and successful management. This review compiles the proposed management strategies for ACNES.

Chronic Abdominal Wall Pain: An Under-Recognized Diagnosis Leading to Unnecessary Testing

Chronic abdominal wall pain (CAWP) refers to a condition wherein pain originates from the abdominal wall itself rather than the underlying viscera. According to various estimates, 10% to 30% of patients with chronic abdominal pain are eventually diagnosed with CAWP, usually after expensive testing has failed to uncover another etiology. The most common cause of CAWP is anterior cutaneous nerve entrapment syndrome. The diagnosis of CAWP is made using an oft-forgotten physical examination finding known as Carnett's sign, where focal abdominal tenderness is either the same or worsened during contraction of the abdominal musculature. CAWP can be confirmed by response to trigger point injection of local anesthetic. Once diagnosis is made, treatment ranges from conservative management to trigger point injection and in refractory cases, even surgery. This review provides an overview of CAWP, discusses the cost and implications of a missed diagnosis, compares somatic versus visceral innervation, describes the pathophysiology of nerve entrapment, and reviews the evidence behind available treatment modalities.

Factors Determining Outcome After Surgery for Chronic Groin Pain Following a Lichtenstein Hernia Repair

BACKGROUND

Some patients develop chronic groin pain after a Lichtenstein hernia repair. Previous studies have demonstrated beneficial effects of removal of entrapped inguinal nerves or a meshectomy in patients with chronic pain after open inguinal hernia mesh repair. Factors determining success following this remedial surgery are unknown. The aim of the study was to identify potential patient- or surgery-related factors predicting the surgical efficacy for inguinodynia following Lichtenstein repair.

METHODS

Consecutive adult patients with a history of persistent pain following Lichtenstein repair who underwent remedial surgery were analysed using univariate analysis. Significant confounders (p < 0.05) were combined in a multivariate logistic regression model using a backward stepwise regression method.

RESULTS

A total of 136 groin pain operations were available for analysis. Factors contributing to success were removal of a meshoma (OR 4.66) or a neuroma (OR 5.60) and the use of spinal anaesthesia (OR 4.38). In contrast, female gender (OR 0.30) and preoperative opioid use (OR 0.38) were significantly associated with a less favourable outcome. Using a multivariate analysis model, surgery under spinal anaesthesia (OR 4.04), preoperative use of opioids (OR 0.37), and meshoma removal (OR 5.31) greatly determined surgical outcome.

CONCLUSIONS

Pain reduction after remedial surgery for chronic groin pain after Lichtenstein repair is more successful if surgery is performed under spinal anaesthesia compared to general anaesthesia. Removal of a meshoma must be considered as success rates are optimized following these measures. Patients using opioids preoperatively have less favourable outcomes.

Prevalence of Anterior Cutaneous Nerve Entrapment Syndrome in a Pediatric Population With Chronic Abdominal Pain

OBJECTIVE

Anterior cutaneous nerve entrapment syndrome (ACNES) is a frequently overlooked condition causing chronic abdominal pain (CAP). The objective of the present study was to investigate the rate of ACNES in a pediatric outpatient cohort with CAP.

METHODS

A cross-sectional cohort study was conducted in a population 10 to 18 years of age consulting a pediatric outpatient department with new-onset CAP during a 2 years' time period. All individuals were identified through a standard hospital registration system. History, physical examination, diagnosis, and success of treatment were obtained in patients who were diagnosed as having ACNES.

RESULTS

Twelve of 95 adolescents with CAP were found to be experiencing ACNES. Carnett sign was positive at the lateral border of the rectus abdominus muscle in all 12. Altered skin sensation was present in 11 of 12 patients with ACNES. Six weeks after treatment (1-3 injections, n = 5; neurectomy, n = 7), pain was absent in 11 patients.

CONCLUSIONS

ACNES is present in 1 of 8 adolescents presenting with CAP to a pediatric outpatient department of a teaching hospital. Simple physical examinational testing allows for the diagnosis. Treatments including nerve blocks or surgery are beneficial in most.

Incidence of abdominal pain due to the anterior cutaneous nerve entrapment syndrome in an emergency department

Background

Patients with chronic abdominal pain occasionally suffer from the anterior cutaneous nerve entrapment syndrome (ACNES). A substantial number of patients report previous visits to an emergency department (ED) with acute pain. Aim of this study was to obtain the incidence of ACNES in patients presenting with abdominal pain in the ED of a Dutch teaching hospital.

Methods

In this observational study, data sets of all patients visiting Máxima Medical Center’s (MMC) ED in 2011–2012 were searched for key terms ‘ACNES’, ‘intercostal neuralgia’ or ‘abdominal wall pain’. Files of potential patients living within hospital’s adherence area were checked using accepted criteria indicating the presence of ACNES. Disease incidence was calculated as a ratio to the hospital’s adherence data. The ACNES MMC 2013’s incidence in patients evaluated in the surgical outpatient department was also calculated.

Results

During the study period, 473 ED patient files met inclusion criteria. A total of 88 patients belonging to MMC’s adherence area were diagnosed with ACNES leading to a mean 22/100.000 ACNES yearly incidence rate. About one of 50 patients with abdominal pain visiting the ED suffered from ACNES. A 35/100.000 outpatient department ACNES incidence rate was calculated in the year of 2013. Combining these two ratios, a 1:1800 ACNES incidence in the general population was obtained.

Conclusions

In an ED setting of a Dutch teaching hospital, approximately 2% of patients presenting with acute abdominal pain suffered from ACNES. ED physicians should consider ACNES in abdominal pain patients with normal laboratory or imaging tests.