Canal pressures before, during, and after endoscopic release for idiopathic carpal tunnel syndrome.

A special transducer was used to measure in situ carpal tunnel pressures in 20 patients who had surgery for idiopathic carpal tunnel syndrome (CTS) by one-portal endoscopic section of the flexor retinaculum. Pressures were elevated initially. The pressures were maximal (mean, 93 mm Hg) with full passive wrist extension. Peaks of high pressures, on average 97 mm Hg, were recorded with the Agee (MicroAire, Charlottesville, VA) endoscopic device in the canal. Release of the endoscopic flexor retinaculum resulted in a marked decrease of the pressures.