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

Sponsor

Maxima Medical Center (Other)

Overall Status

Not yet recruiting

CT.gov ID

NCT05678127

Collaborator

(none)

Enrollment

Location

Arm

5.9

Anticipated Duration (Months)

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

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.

Condition or Disease	Intervention/Treatment	Phase
Anterior Cutaneous Nerve Entrapment Syndrome Nerve Entrapment Syndrome Chronic Pain Syndrome Diagnosis	Procedure: Skin biopsy	N/A

Study Design

Study Type:

Interventional

Anticipated Enrollment :

12 participants

Allocation:

N/A

Intervention Model:

Single Group Assignment

Intervention Model Description:

Skin biopsies will be performed on patients with an unilateral ACNES. Biopsies will be taken at the triggerpoint (affected side) and contralateral, non-affected side of the abdominal wall. Affected vs non-affected will be compared. The non-affected side serves as control.Skin biopsies will be performed on patients with an unilateral ACNES. Biopsies will be taken at the triggerpoint (affected side) and contralateral, non-affected side of the abdominal wall. Affected vs non-affected will be compared. The non-affected side serves as control.

Masking:

None (Open Label)

Masking Description:

The pathologists who will measure the nerve fibre density are blinded; they will not know if the biopsy is from the affected or non-affected side.

Primary Purpose:

Diagnostic

Official Title:

Skin Biopsy as Diagnostic Tool in Anterior Cutaneous Nerve Entrapment Syndrome (ACNES): A Pilot Study

Anticipated Study Start Date :

Jan 1, 2023

Anticipated Primary Completion Date :

Jun 1, 2023

Anticipated Study Completion Date :

Jul 1, 2023

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Patients with unilateral ACNES	Procedure: Skin biopsy Two 3mm skin biopsies from the abdominal wall will be taken. One at the triggerpoint of the pain, the second one at the contralateral, non-affected side of the abdominal wall. Lidocaine will be used for local anaesthesia of the skin, before the biopsies will be taken.

Arm

Intervention/Treatment

Experimental: Patients with unilateral ACNES

Procedure: Skin biopsy

Two 3mm skin biopsies from the abdominal wall will be taken. One at the triggerpoint of the pain, the second one at the contralateral, non-affected side of the abdominal wall. Lidocaine will be used for local anaesthesia of the skin, before the biopsies will be taken.

Outcome Measures

Primary Outcome Measures

Intraepidermal Nerve Fibre density (IENFD) [Both biopsies will be taken at the same time, as their difference will be studied. The biopsies will be taken at the second outpatient visit, 2 or 3 weeks after the first visit, just after the second triggger point injection (standard of care).]
Difference in IENFD (measured in IENF/mm) from both affected and non-affected side of the abdominal wall.

Secondary Outcome Measures

Pain score [Assessed at first outpatient visit, used as baseline data.]
Average pain score, assessed using the Numeric Rating Scale (NRS) 0-10 before start of treatment. 0 no pain, 10 worst possible pain.
Duration of pain [Assessed at first outpatient visit, used as baseline data.]
Duration of pain in months before diagnosis
Treatment response [Treatment response will be assessed 2 to 6 weeks after each treatment (trigger point injections, PRF and neurectomy), as standard of care.]
Patients will receive standard of care treatment for ACNES. Treatment is unsuccessful if <50% pain reduction or when patients are not satisfied with their pain relief and want additional treatment.

Eligibility Criteria

Criteria

Ages Eligible for Study:

21 Years to 40 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

Duration of pain >3 months
Newly diagnosed unilateral ACNES
Fully completed intake questionnaire
Obtained written informed consent

Exclusion Criteria:

Inability to understand Dutch language
Bilateral ACNES
Previously administered injections with corticosteroids at trigger point (injection with a local anaesthetic is allowed)
Previous Pulsed Radiofrequency (PRF)-treatment at trigger point
History of open abdominal surgery
History of neurectomy
Known neuromuscular or neurodegenerative disease
Antiplatelet or anticoagulants use or known coagulation disorders
Disorder known to cause a reduced IENFD;
Diabetes
Hypothyroidism
Renal failure
Vitamin B12 deficiency
Monoclonal gammopathy
Alcohol abuse (>5 IU a day)
Malignancies
Medication that cause neuropathy (for example chemotherapy)