What is the appropriate management of anterior cutaneous nerve entrapment syndrome (ACNES)?

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Last updated: October 29, 2026 • View editorial policy

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Management of ACNES

For patients with anterior cutaneous nerve entrapment syndrome (ACNES), implement a three-step treatment algorithm: start with trigger point injections (TPI) for both diagnosis and initial treatment, progress to pulsed radiofrequency (PRF) if TPI fails, and proceed to surgical neurectomy for refractory cases, which provides the best long-term pain relief. 1

Diagnostic Confirmation

Before initiating treatment, confirm ACNES diagnosis through:

  • Carnett's sign: Increased pain with tensing of abdominal wall muscles
  • Localized tenderness at the lateral border of the rectus abdominis muscle where intercostal nerves penetrate the anterior rectus sheath
  • Small trigger point (typically <2 cm diameter)
  • Diagnostic TPI response: Pain relief following local anesthetic injection confirms the diagnosis 2

Critical pitfall: In pediatric patients, failure to apply the biopsychosocial model leads to unnecessary invasive interventions. In children with suspected ACNES, comprehensive psychosocial assessment is mandatory before proceeding with invasive treatments, as one study found that ACNES diagnosis could not be solidly confirmed in any pediatric cases referred to a tertiary pain center 3.

Step 1: Trigger Point Injections (First-Line)

TPI serves dual purposes: diagnostic confirmation and therapeutic intervention 1, 2.

  • Technique: Inject local anesthetic (with or without corticosteroid) at the point of maximal tenderness
  • Expected outcomes: 30% long-term success rate 1
  • Repeat injections: May be performed if initial response is favorable but pain recurs
  • Ultrasound guidance: Can improve accuracy of injection placement 2

The relatively modest long-term success rate means most patients will require progression to Step 2 or 3.

Step 2: Pulsed Radiofrequency (Second-Line)

For patients who fail conservative TPI management:

  • Success rate: Approximately 20% achieve long-term relief 1
  • Duration of effect: Median 4 months of temporary relief 1
  • Advantage: Minimally invasive compared to surgery
  • Limitation: Effect is typically temporary, requiring repeat procedures or progression to surgery

PRF represents a bridge between conservative and surgical management but should not delay definitive surgical treatment in appropriate candidates.

Step 3: Surgical Neurectomy (Definitive Treatment)

Surgical neurectomy provides superior long-term outcomes with 61% success rate for primary surgery 1.

Surgical Approach Options:

Traditional anterior neurectomy:

  • Direct dissection through anterior rectus sheath at entrapment site
  • Concern: May compromise abdominal wall integrity 4

Posterior neurectomy (preferred when available):

  • Access via retrorectus space
  • Proximal nerve division before fascial penetration
  • Advantages: Avoids direct transfascial dissection at entrapment site 4

MEPONE technique (Minimally Invasive Extraperitoneal Posterior Neurectomy):

  • Uses eTEP principles for extraperitoneal dissection
  • Mean operative time: 35 minutes
  • Pain reduction: NRS decreased from 6.9 to 1.5 at 3 months and 2.1 at 12 months (p<0.0001) 4
  • Complete pain relief (NRS 0-1): 43% of patients
  • Significant pain reduction (>50%): Additional 33% of patients
  • Low complication rate with minimal abdominal wall trauma 4

Management of Recurrent Pain After Surgery

For patients with recurrent pain after initially successful posterior neurectomy:

Redo-posterior neurectomy is strongly recommended over conservative management 5:

  • Short-term success: 95%
  • Long-term success (median 40 months): 85% vs 41% for conservative treatment (p=0.008)
  • Patient satisfaction significantly higher: 70% vs 41% (p=0.018)

Key distinction: Recurrent pain (pain returns after pain-free period) responds significantly better to redo-surgery than residual pain (pain never fully resolved) 1.

Emerging Techniques

Peripheral nerve stimulation (PNS):

  • Reserved for refractory cases unresponsive to standard treatments
  • Case reports show up to 80% pain reduction at 3-6 months 6
  • Evidence limited to case reports; requires larger studies 6
  • Consider for patients with complex surgical history or contraindications to neurectomy

Radiofrequency ablation: Mentioned as emerging technique but insufficient evidence for routine recommendation 2.

Critical Management Principles

  1. Avoid one-dimensional approach: Particularly in pediatric patients, psychosocial factors must be addressed alongside physical interventions 3

  2. Standardize outcome measures: Success defined as ≥50% NRS reduction and/or ≥2-point VRS reduction 1

  3. Timing matters: Don't delay surgical referral in patients failing conservative measures, as neurectomy provides superior long-term outcomes 1

  4. Multidisciplinary collaboration: Work with pain specialists for comprehensive management, especially for complex or refractory cases 1

  5. Patient selection for surgery: Best candidates are those with clear diagnostic confirmation via TPI response and localized symptoms refractory to conservative management

References

1
Research

Management strategies for anterior cutaneous nerve entrapment syndrome: a scoping review.

Hernia : the journal of hernias and abdominal wall surgery, 2026

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.