The carpal tunnel syndrome is a bilateral disorder.

We studied, retrospectively, 131 patients who had undergone an open operation for the carpal tunnel syndrome (CTS) in 229 hands. The symptoms were present on both sides in 59% of patients when first seen. Neurophysiological impairment of the median nerve was observed in 66% of the asymptomatic hands, and 73% of patients in this group developed symptoms of CTS after the opposite side had been operated on. Follow-up of patients with unilateral CTS showed that the subsequent development of disease in the unaffected hand is very common. We conclude that CTS is a bilateral disorder and that it becomes more evident as time passes. There is a correlation between the duration of symptoms and bilateral occurrence.