A Pilot Study to Explore the Use of Skin Biopsy as Diagnostic Tool in Anterior Cutaneous Nerve Entrapment Syndrome (ACNES)

ACNES is a neuropathic pain condition of the abdominal wall. It is a clinical diagnosis based on patient's history and physical examination. No diagnostic test is available to confirm the diagnosis.This pilot study will determine if skin biopsies can be used as diagnostic test. Two 3mm biopsies will be taken and used to count the small nerve fibres in the skin. The number of small nerve fibres of the painful skin will be compared to non-painful skin. Skin biopsy and small fibre nerve count is already used as diagnostic test in patients with small-fibre neuropathy.The investigators hypothesize that patients with ACNES will have a reduced number of small nerve fibres in the affected skin, compared to the non-affected skin.

Inclusion Criteria:Duration of pain >3 monthsNewly diagnosed unilateral ACNESFully completed intake questionnaireObtained written informed consentExclusion Criteria:Inability to understand Dutch languageBilateral ACNESPreviously administered injections with corticosteroids at trigger point (injection with a local anaesthetic is allowed)Previous Pulsed Radiofrequency (PRF)-treatment at trigger pointHistory of open abdominal surgeryHistory of neurectomyKnown neuromuscular or neurodegenerative diseaseAntiplatelet or anticoagulants use or known coagulation disordersDisorder known to cause a reduced IENFD;DiabetesHypothyroidismRenal failureVitamin B12 deficiencyMonoclonal gammopathyAlcohol abuse (>5 IU a day)MalignanciesMedication that cause neuropathy (for example chemotherapy)