MeDe Study: Comparing Median Nerve Decompression at the Carpal Tunnel Alone Versus Median Nerve Decompression at Both the Carpal Tunnel and Lacertus Fibrosis in Adults With Carpal Tunnel Syndrome (MeDe)

June 25, 2026 updated by: Maasstad Hospital

MeDe Study: A Randomized Controlled Trial Comparing Median Nerve Decompression at the Carpal Tunnel Alone Versus Median Nerve Decompression at Both the Carpal Tunnel and Lacertus Fibrosis in Adults With Carpal Tunnel Syndrome

Carpal tunnel syndrome (CTS) is a condition that can cause pain, numbness, or tingling in the hand and wrist. The most common surgery for CTS is called carpal tunnel release, which aims to relieve pressure on the main nerve in the wrist.

However, after this surgery, some patients (up to 4 out of 10) still have symptoms, and about 1 in 8 may need another surgery. One reason symptoms can continue is that the nerve may also be compressed higher up in the arm, near a ligament called the Lacertus fibrosus. Releasing this area might help, but it is often not checked or treated during the first surgery because current tests (like physical exams, nerve studies, and ultrasounds) cannot reliably detect it.

This study is comparing two approaches for people with CTS:

  1. Standard surgery - only releasing the carpal tunnel.
  2. Extended surgery - releasing both the carpal tunnel and the Lacertus fibrosus.

The goal is to see which surgery helps patients feel better and have fewer symptoms in the hand and wrist after treatment.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Carpal tunnel release is the most commonly performed surgical procedure in patients diagnosed with carpal tunnel syndrome (CTS). Nevertheless, up to 43% of patients experience residual symptoms, necessitating secondary surgical interventions in approximately one out of eight carpal tunnel releases.

These residual symptoms may be attributable to proximal median nerve compression (PMNC), which can potentially be alleviated by performing a Lacertus release. However, diagnosing PMNC poses a challenge, as standard diagnostic tools like physical examination, electromyography (EMG) and ultrasound lack the specificity to distinguish between CTS and PMNC. Consequently, PMNC often goes undetected and untreated during initial evaluations.

This randomised trial compares patient reported outcomes following median nerve decompression at the carpal tunnel alone versus median nerve decompression at both the carpal tunnel and the Lacertus fibrosus in individuals with CTS.

Study Type

Interventional

Enrollment (Estimated)

110

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Netherlands
    • South Holland
      • Rotterdam, South Holland, Netherlands, 3079 DZ
        • Recruiting
        • Maasstad ziekenhuis
        • Contact:
        • Sub-Investigator:
          • Sebastian Poggio Voormolen, BSc, PhD candidate
        • Sub-Investigator:
          • Ileen Domela Nieuwenhuis Nyegaard, MD, PhD candidate
        • Principal Investigator:
          • Niels W.L Schep, MD, PhD
      • Rotterdam, South Holland, Netherlands, 3201 GZ
        • Recruiting
        • Spijkenise Medisch Centrum
        • Contact:
        • Sub-Investigator:
          • Sebastian Poggio Voormolen, BSc, PhD candidate
        • Sub-Investigator:
          • Ileen Domela Nieuwenhuis Nyegaard, MD, PhD candidate
        • Principal Investigator:
          • Niels W.L Schep, MD, PhD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Patients being at least 18 years or older
  • CTS confirmed by EMG or nerve ultrasound
  • Patient opts for surgical treatment

Exclusion Criteria:

  • Previous surgical decompression of the median nerve at the ipsilateral wrist or forearm
  • Severe thenar atrophy: Examination of the thenar is based on clinical observation. The presence of thenar muscle atrophy is scored as none, mild, or severe.
  • Simultaneous nerve decompression in the ipsilateral arm (e.g. cubital tunnel, Guyon and radial nerve release.
  • Neurological disorders affecting peripheral nerves (e.g. spinal cord compression or injury, muscular dystrophy, dystonia, ALS)
  • Malunion of the distal radius
  • Impaired hand function
  • Pregnancy
  • Inability to complete study forms due to insufficient comprehension of the Dutch language

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: carpal tunnel release
Control group
Procedure: Carpal tunnel release
Carpal tunnel release is a surgical procedure to treat carpal tunnel syndrome by cutting the ligament (transverse carpal ligament) covering the wrist's carpal tunnel. This action relieves pressure on the median nerve, alleviating pain, numbness, and weakness in the hand. It is usually an outpatient procedure done under local anesthesia.
Other: carpal tunnel release combined with Lacertus release
Intervention group
Procedure: Combined carpal tunnel and lacertus release
A transverse incision is made on the forearm's volar (anterior) aspect, approximately 3cm distal of the elbow crease. This incision is placed over the palpable brachioradialis and biceps tendon. The subcutaneous tissue is dissected to expose the fascia overlying the flexor pronator muscles. The brachial fascia is identified and incised to reveal the underlying Lacertus fibrosus (also known as the bicipital aponeurosis). The Lacertus fibrosus is a tendinous band extending from the biceps tendon medially across the forearm. Care is taken to avoid injury to the underlying structures, particularly the median nerve, which lies deep and slightly medial to the Lacertus fibrosus. The Lacertus fibrosus is incised transversely. The surgeon ensures that the median nerve is fully decompressed and that there are no remaining constrictive bands. It is usually an outpatient procedure done under local anesthesia.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Boston Carpal Tunnel Questionnaire Symptom Severity Scale (BCTQ SSS)
Time Frame: At twelve months follow-up
Scores range from 1 to 5. A higher score indicates a more severe level of impairment or discomfort.
At twelve months follow-up

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pillar pain
Time Frame: From 6 weeks after surgery until 12 months of follow-up
The presence of tenderness or pain in the thenar or hypothenar area around the hook of the hamate and the unciform process of the trapezium
From 6 weeks after surgery until 12 months of follow-up
(Return to) work using the QuickDASH work module.
Time Frame: From enrollment until 6 months of follow-up.
From enrollment until 6 months of follow-up.
Sensibility
Time Frame: From enrollment until 12 months of follow-up.
Monofilament test on the tuft of the 3rd digit and the proximal thenar. The tuft of the 5th digit and the distal thenar will be measured and used as a reference.
From enrollment until 12 months of follow-up.
Tip-pinch strength
Time Frame: From enrollment until 12 months of follow-up
Tip-to-tip pinch strength of the first and second digit will be measured with a baseline pinch gauge.
From enrollment until 12 months of follow-up
Cost-effectiveness of intervention
Time Frame: From enrollment until 12 months of follow-up
Measured with health care resource utilisation and costs (iMCQ, iPCQ).
From enrollment until 12 months of follow-up
Boston Carpal Tunnel Questionnaire Functional Status Scale (BCTQ FSS)
Time Frame: From enrollment until 12 months of follow-up
Scores range from 1 to 5. A higher score indicates a more severe level of impairment or discomfort.
From enrollment until 12 months of follow-up
Anchor questions
Time Frame: At 12 months follow-up
Regarding patient satisfaction to analyse minimal clinically important difference (MCID)
At 12 months follow-up
Number of participants with residual, persistent en recurrent CTS symptoms
Time Frame: From 6 weeks after surgery until 12 months of follow-up
From 6 weeks after surgery until 12 months of follow-up
Number of participants undergoing secondary surgery
Time Frame: From 6 weeks until 12 months of follow-up.
This includes, but is not limited to, nerve decompression, internal or external neurolysis, and flap reconstruction in the ipsilateral arm.
From 6 weeks until 12 months of follow-up.
Number of participants that experienced complications or adverse events
Time Frame: From enrollment until 12 months of follow-up.
Such as infection, seroma, and tendon and neurovascular damage.
From enrollment until 12 months of follow-up.
5-level EuroQol (EQ-5D-5L): Quality of life
Time Frame: Will be assessed at baseline and at 12 months of follow-up.
Will be assessed using the 5-level EuroQol (EQ-5D-5L) questionnaire.
Will be assessed at baseline and at 12 months of follow-up.
Physical examination
Time Frame: From enrollment until 12 months of follow-up.

OK-sign, FLP and FDP2 strength separately (compared to contralateral hand). Scratch collapse test over the carpal tunnel and Lacertus fibrosis (positive or negative).

Phalen and Tinel test (positive or negative).
From enrollment until 12 months of follow-up.
Exploratory ultrasound
Time Frame: Will be assessed at baseline and 3 months.
Changes in median nerve cross-sectional diameter (mm) to evaluate postoperative changes in nerve size over time, measured by nerve ultrasound.
Will be assessed at baseline and 3 months.

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Patient Demographics
Time Frame: At baseline
Age, sex, labour (blue versus white collar), hand dominance and medical history regarding comorbidities and hand-specific conditions
At baseline

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Maasstad Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 6, 2026

Primary Completion (Estimated)

February 1, 2028

Study Completion (Estimated)

February 1, 2028

Study Registration Dates

First Submitted

May 11, 2026

First Submitted That Met QC Criteria

May 11, 2026

First Posted (Actual)

May 19, 2026

Study Record Updates

Last Update Posted (Actual)

June 26, 2026

Last Update Submitted That Met QC Criteria

June 25, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • NL-OMON57619
  • NL-005174 (Registry Identifier: CCMO: Research with human participants)
  • NL87289.100.2 (Other Identifier: ICTRP)
  • R24.082 (Other Identifier: MEC-U)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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