Abdominal Cutaneous Nerve Entrapment Syndrome (ACNES)

The Management of Abdominal Cutaneous Nerve Entrapment Syndrome

Nerve entrapment as a cause of chronic abdominal pain is frequently overlooked. A series of nerves pass through the muscles of the abdomen before reaching the skin to carry sensations. They can get trapped within the muscles leading to severe pain resulting in a condition known as Abdominal Cutaneous Nerve Entrapment Syndrome (ACNES). ACNES affects between 10-30% of patients with chronic abdominal wall pain. A definitive diagnosis of ACNES is obtained by anaesthetising these nerves. Initial management includes education and avoidance of known triggers. It is common practice to inject steroid with local anaesthetic during the diagnostic injections itself to prolong pain relief. Like other nerve entrapment conditions, this is also refractory to medical treatment. Hence repeated injections and nerve entrapment release surgery are commonly carried out.

In Aberdeen, a number of patients have been treated for this condition. A cohort of patients have benefitted with injection alone while recurrence has been noted in patients who have undergone surgery. This project aims to gain more understanding about the clinical course of patients with suspected ACNES by evaluation of the clinic progress.

Study Overview

• Status: Completed
• Conditions: Abdominal Pain; Abdominal Cutaneous Nerve Entrapment Syndrome
• Intervention / Treatment: Procedure: Injection to or release of anterior cutaneous nerves

Detailed Description

This is a cross-sectional survey, best suited to evaluate the effect of treatments. Potential participants will be identified from a list of patients who have attended the pain clinic at Aberdeen Royal Infirmary for chronic abdominal wall pain.

These patients will be invited to participate in the study via posted letter. The letter will include a participant information sheet detailing who is running the study, what the purpose of the study is, what participating in the study requires of a patient and how their information will be used.

Patients who wish to participate will return a note of interest, included within the participant information pack, and will then be invited to attend an outpatient clinic in the Aberdeen Health Care and Community Village. Informed consent will be obtained. The questionnaire will be distributed. It is estimated that the questionnaire will take approximately 15 minutes to complete. Each completed questionnaire will be reviewed immediately by a member of the research team to ensure all relevant sections have been completed. Following completion of the questionnaire, patients will be allowed to leave. It is not anticipated that participants will need to be contacted after submitting their completed questionnaire. Participants who explicit express the need for further pain management will be referred to NHS Grampian pain clinic.

A response from potential participants will be awaited for 4 weeks. In the event of no response, a maximum of 2 written reminders 4 weeks apart will be sent along with participant information pack.

The questionnaires have previously been validated for use in neuropathic pain, and the outcomes of the questionnaire are consistent with those recommended by the 2008 Initiative on Methods, Measurement and Pain Assessment in Clinical Trials (IMMPACT) publication. 17

The questionnaire will consist of four main sections: baseline demographic details, a detailed pain history prior to surgery, including questions from the Brief Pain Inventory, 18 open-ended questions to explore the patient's opinions of both the operation and their health status since and, finally, an overall picture of health using the European Quality of Life-5 Dimensions (EQ-5D) Score 19 and patient global impression of change scale. 20

In order to compare pain both before and after surgery, participants will be asked to complete these sections twice, focusing on their previous health state and their current health.

Since pain scores are not routinely collected and all patients will be seen after surgery, pre-operative pain scores will be retrospective.

• Study Type: Observational
• Enrollment (Actual): 35

Contacts and Locations

Study Locations

• United Kingdom
  • Scotland
    • Aberdeen, Scotland, United Kingdom, AB25 2 ZN
      • Aberdeen Royal Infirmary

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years and older (Child, Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Potential participants will be identified from the hospital electronic booking system.

A list of patients between January 2010 and December 2015 and had injection for chronic abdominal wall pain will be invited for the study.

Description

Inclusion Criteria:

In order to be eligible for inclusion, all patients must:

• Be aged 16 or over
• Be able to understand English
• Be able to give informed consent
• Be able to report on their health and pain status (neurologically stable)
• Should have undergone either injection or surgery for suspected ACNES

Exclusion Criteria:

Patients will be excluded if they:

• Are not able to understand what is required of them
• Are not able to give informed consent

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Retrospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Success rate of intervention	An intervention either injection or surgery is classed as success when there is either a 2 point difference in the average pain scores pre and post intervention or more than 30% improvement as rated by the participant in the Brief Pain Inventory used for evaluating the pain baseline and follow-up.	3 months

Collaborators and Investigators

• Sponsor: University of Aberdeen
• Collaborators: NHS Grampian
• Investigators: Principal Investigator: Saravanakumar Kanakarajan, MD, NHS Grampian

Publications and helpful links

General Publications

• Kanakarajan S, Dharmavaram S, Tadros A, Pushparaj H, Rose A. Abdominal cutaneous nerve entrapment syndrome: A cross sectional survey of treatment outcomes. Br J Pain. 2022 Oct;16(5):538-545. doi: 10.1177/20494637221101719. Epub 2022 May 20.

Helpful Links

• National Library of Medicine

Study record dates

Study Major Dates

• Study Start (Actual): September 15, 2017
• Primary Completion (Actual): September 19, 2018
• Study Completion (Actual): September 19, 2018

Study Registration Dates

• First Submitted: June 20, 2018
• First Submitted That Met QC Criteria: June 20, 2018
• First Posted (Actual): July 2, 2018

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: December 18, 2024
• Last Verified: December 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Nervous System Diseases; Pathologic Processes; Neuromuscular Diseases; Genetic Diseases, Inborn; Signs and Symptoms, Digestive; Peripheral Nervous System Diseases; Disease; Neurodegenerative Diseases; Congenital Abnormalities; Heredodegenerative Disorders, Nervous System; Nervous System Malformations; Polyneuropathies; Abdominal Pain; Syndrome; Charcot-Marie-Tooth Disease; Nerve Compression Syndromes; Hereditary Sensory and Motor Neuropathy
• Other Study ID Numbers: 2017AN003

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No