Clinical Trial: Nociceptive Processing in Acute Cutaneous Nerve Entrapment Syndrome

Study Status: Completed
Recruit Status: Completed
Study Type: Observational

Official Title: Nociceptive Processing in Acute Cutaneous Nerve Entrapment Syndrome: a Quantitative Sensory Testing Analysis.

Brief Summary:

Rationale: Chronic abdominal pain is a frequently occurring condition. Although hardly ever considered, the abdominal wall is the primary cause in 10-30% of cases. Most often it is caused by entrapment of an intercostal nerve in the anterior rectus sheath, the Anterior Cutaneous Nerve Entrapment Syndrome (ACNES). Treatment consists of local anaesthetic injections combined with methyl-prednisolon. When ineffective, a neurectomy at the site of penetration out of the ventral rectus sheet should be considered. This neurectomy however is effective in 73% of cases, leaving some 25% of patients in pain. Whether these refractory ACNES patients suffer from underlying pathologic pain disorders is subject to investigation, by using quantitative sensory testing (QST).

Objective: To investigate nociceptive processing and possible underlying pathological pain processing mechanisms in ACNES patients.

Study design: An observational case-control study.

Study population: Patients treated for ACNES (n = 50) compared to healthy controls from an existing database.

Measurements: Quantitative sensory testing (QST) of nociception, performed after treatment of ACNES for both successfully treated and refractory patients in comparison to healthy controls. Visual Analogue Scores (VAS) measured before, during and after testing procedures. Pain Anxiety Symptom Scale (PASS) and Pain Catastrophizing Scale (PCS) questionnaires.

Main study parameters: Pressure pain and electrical pain thresholds as investigated by QST. Secondary study parameters are VAS-scores and results of PASS and PCS questionnaires.


Detailed Summary:
Sponsor: Radboud University

Current Primary Outcome: pressure pain threshold [ Time Frame: > 6 weeks after treatment ]

The pressure pain threshold (pPT) will be determined by pressing an electronic pressure algometer, which has a surface area of 1 cm2, on a distinct muscles. The patient will be asked to say 'now' when the sensation is rated as unpleasant. The pressure will be increased at a rate of 50 kPa/sec until the pPT is reached.


Original Primary Outcome: Same as current

Current Secondary Outcome:

  • Electrical Sensation Threshold (eST) [ Time Frame: > 6 weeks after treatment ]

    Electrical QST will be measured using a computerized electric stimulation device delivering constant current skin stimulation via self-adhesive electrodes.

    Electric sensation threshold (eST): when electric sensation is first felt.

  • Electrical Pain Threshold (ePT) [ Time Frame: > 6 weeks after treatment ]

    Electrical QST will be measured using a computerized electric stimulation device delivering constant current skin stimulation via self-adhesive electrodes.

    Electric pain threshold (ePT): when electric sensation is rated as unpleasant

  • Electrical Pain Tolerance Threshold (ePTT) [ Time Frame: >6 weeks after treatment ]

    Electrical QST will be measured using a computerized electric stimulation device delivering constant current skin stimulation via self-adhesive electrodes.

    Electric pain tolerance threshold (ePTT): when electric sensation is intolerable.

  • Electric Wind-Up Response (e-WUR) [ Time Frame: > 6 weeks after treatment ]

    Electrical QST will be measured using a computerized electric stimulation device delivering constant current skin stimulation via self-adhesive electrodes.

    Electric wind-up response (eWUR): rated pain after repeated stimuli

  • Visual Analogue Scale [ Time Frame: > 6 weeks after treatment ]
    Patients will be asked to mark on a 100mm VAS line the average pain in a pain diary. The boundaries of these lines are "no pain" on the upper left site and "unbearable pain" on the upper right site.


Original Secondary Outcome: Same as current

Information By: Radboud University

Dates:
Date Received: July 12, 2013
Date Started: June 2013
Date Completion:
Last Updated: November 14, 2014
Last Verified: November 2014