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.

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