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NCT Number: NCT07594821

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

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.

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Key information

Conditions

Carpal Tunnel Syndrome (CTS) Carpal Tunnel Syndrome Cumulative Trauma Disorders Lacertus Syndrome Median Neuropathy Mononeuropathies Nerve Compression Syndromes Nervous System Diseases Neuromuscular Diseases Peripheral Nervous System Diseases Sprains and Strains Wounds and Injuries

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Maasstad Ziekenhuis, Rotterdam, South Holland, Netherlands

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About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Carpal tunnel release

Procedure

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.

Combined carpal tunnel and lacertus release

Procedure

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.

Primary outcomes

  1. 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.

Secondary outcomes

  1. 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.

  2. Anchor questions

    Time frame: At 12 months follow-up

    Regarding patient satisfaction to analyse minimal clinically important difference (MCID)

  3. Number of participants with residual, persistent en recurrent CTS symptoms

    Time frame: From 6 weeks after surgery until 12 months of follow-up

  4. 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

  5. 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.

  6. 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.

  7. (Return to) work using the QuickDASH work module.

    Time frame: From enrollment until 6 months of follow-up.

  8. 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.

  9. 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.

  10. Cost-effectiveness of intervention

    Time frame: From enrollment until 12 months of follow-up

    Measured with health care resource utilisation and costs (iMCQ, iPCQ).

  11. 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.

  12. 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).

  13. 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.

Other outcomes

  1. Patient Demographics

    Time frame: At baseline

    Age, sex, labour (blue versus white collar), hand dominance and medical history regarding comorbidities and hand-specific conditions

Study contacts

Contact information is provided by the study sponsor or research team.

Sebastian Poggio Voormolen, BSc, PhD candidate

CONTACT

[email protected]

+31 6 46560865

Sponsors and collaborators

Lead sponsor

Maasstad Hospital

Other

Registry information

Official study title

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

Acronym: MeDe

Important dates

Study start
2026
Primary completion
2028
Study completion
2028
First posted
May 19, 2026
Registry last updated
Jun 26, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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