Comparison of Long-term Outcomes Following Endoscopic or Open Surgery for Carpal Tunnel Syndrome

Endoscopic Versus Open Carpal Tunnel Release: 10 to 15 Years Follow-up of a Randomized Controlled Trial

No randomized trials have compared long-term outcomes following endoscopic and open carpal tunnel release in patients with carpal tunnel syndrome (CTS). The investigators conducted a single-center randomized controlled trial between January 1998 and December 2002, including 128 patients (25 to 60 years) with clinically diagnosed and electrophysiologically confirmed idiopathic CTS. The outcome measures included the validated CTS symptom severity and functional status scales completed at baseline and 1 year postoperatively. The trial showed that the 1-year outcomes of open and endoscopic carpal tunnel release regarding symptoms and function were equivalent. This extended follow-up of the randomized trial will primarily measure the symptom outcomes at 10-15 years after surgery. A questionnaire will be sent by mail to the patients. The questionnaire will consist of the CTS symptom severity and functional status scales, the 6-item CTS symptoms scale (CTS-6), the 11-item disabilities of the arm, shoulder and hand (QuickDASH), the 2-item palmar pain scale, and a visual analog scale about treatment satisfaction. The patients will also be asked about whether they had undergone further surgery for CTS in the same or contralateral hand after their operation in the randomized trial. The completed questionnaires will be scanned into a database. The scores for the different scales will be calculated. Analysis will include comparison between the open and endoscopic groups as well as within-group changes of scores from 1 year to 10-15 years.

Inclusion Criteria (original trial):

• Primary idiopathic carpal tunnel syndrome
• age 25-60 years
• currently employed
• duration of symptoms of at least three months
• inadequate response to six weeks' treatment with wrist splint
• symptoms of classic or probable carpal tunnel syndrome according to the diagnostic criteria in the Katz hand diagram, and nerve conduction test showing median neuropathy at the wrist (distal motor latency ≥4.5 milliseconds, wrist-digit sensory latency ≥3.5 milliseconds, or sensory conduction velocity at the carpal tunnel segment <40 metres/second but no other abnormalities.

Exclusion Criteria (original trial):

Inflammatory joint disease

• diabetes mellitus, thyroid disorder, pregnancy, trauma to the affected hand during the preceding year
• previous carpal tunnel release surgery in the affected hand
• carpal tunnel release surgery in the contralateral hand during the preceding year
• symptoms of carpal tunnel syndrome in the contralateral hand not adequately relieved by splint at the time of enrollment
• current sick leave because of disorders other than carpal tunnel syndrome
• inability to complete questionnaires because of language problem or cognitive disorder.