The authors measured carpal canal pressures in 103 patients with idiopathic carpal tunnel syndrome preoperatively and at 2, 6, and 12 months postoperatively. A control group consisted of 25 additional subjects without carpal tunnel syndrome who underwent carpal canal pressure measurements. Immediately after open surgical release, there was a significant decrease of the carpal canal pressures. During the second postoperative month, there was a significant increase of the canal pressures that persisted up to 12 months. However, the slightly elevated pressures remained within the normal control range.
Previous studies have reported that the changes in carpal canal pressure after surgery, but only during the early postoperative period. The authors of this study showed a small rise in carpal canal pressures 2 months postoperatively that persisted for up to 1 year. They theororized that the pressure elevations could be due to scar proliferation within the carpal canal or reconstitution of the carpal ligament by the normal scar process, but with lengthening of the reconstituted ligament such that the intracanal pressures remained within a normal range.