手指の肢位による手根管内圧変化の測定

抄録

Pressure measurement in the carpal canal is often reported. However because the carpal canal is not a closed cavity, compression pressure measurement is more suited than internal pressure measurement to investigate the effects on the median nerve.
We measured the compression pressure between the median nerve and transverse carpal ligament in patients with carpal tunnel syndrome using an air packed type pressure measurement device. A sensor for pressure measurement was inserted between the median nerve and transverse carpal ligament and used to register pressure at varying degrees of wrist and MP-joint flexion, before release of the carpal tunnel.
At the neutral position, the mean pressure was 33.8 mmHg, at the modified Phallens position 37.9 mmHg, and in MP-joint flexion 50.6 mmHg.
We believe the mechanism of the increase in pressure is as follows: as the wrist and MP-joint are flexed, the median nerve in the carpal tunnel bends around the transverse carpal ligament. At the same time the nerve is subjected to compression against this ligament by tensed overlying flexor tendons that also bend around the ligament.