Concurrent musculoskeletal and soft tissue pain in the upper extremity can affect the treatment and prognosis of carpal tunnel syndrome: redefining a common condition.

Objective: To demonstrate the importance of recognizing and separating nonmedian nerve-related symptoms from those related to median nerve compression at the carpal tunnel.

Methods: The records of 80 patients, aged 31-82 years (39 males and 41 females), who had undergone median nerve decompression using open and endoscopic release surgery, were reviewed. Peripheral electrodiagnostic studies were performed in all patients prior to surgery. Those whose nonmedian nerve-related symptoms, also known as musculoskeletal and soft tissue pain and tenderness, persisted postoperatively, were referred to another electrodiagnostic study to reassess the median nerve function at the carpal tunnel. Peripheral electrodiagnostic studies were deemed unnecessary for patients with exclusively median nerve-related symptoms who improved dramatically following surgery. Included from the study were cases whose presenting symptoms were primarily referrable to median nerve dysfunction with or without associated musculoskeletal pain. Cases that were excluded were those whose symptoms were related to various primary conditions. Outcome of surgery was reviewed and correlated with symptoms related to median nerve compression and musculoskeletal irritation, and with electrodiagnostic abnormalities.

Results: Complete resolution of symptoms, following surgery, occurred in patients with clinical and electrophysiologic signs of median nerve compression but without significant symptoms of musculoskeletal irritation. Those with concurrent and prominent musculoskeletal and soft tissue pain had variable results, both favorable and unfavorable, including three who developed signs and symptoms of complex regional pain syndrome.

Conclusion: The symptoms related to median nerve compression at the carpal tunnel and the symptoms related to musculoskeletal and soft tissue irritation are two different symptom complexes that have important diagnostic and therapeutic considerations. We would like to propose that "true carpal tunnel syndrome" symptoms, those that are exclusively median nerve related, should be considered a distinct entity. When musculoskeletal and soft tissue pain is more prominent and dominates the overall clinical presentation, the term "mechanical stress syndrome" is more appropriate.