[Measurement of external pressure of peroneal nerve tract coming in contact with lithotomy leg holders using pressure distribution measurement system BIG-MAT®].

We investigated external pressure on peroneal nerve tract coming in contact with two kinds of leg holders using pressure distribution measurement system BIG- MAT® (Nitta Corp., Osaka) in the lithotomy position Peak contact (active) pressure at the left fibular head region coming in contact with knee-crutch-type leg holder M® (Takara Belmont Corp., Osaka), which supports the left popliteal fossa, was 78.0 ± 26.4 mmHg. On the other hand, peak contact pressure at the left lateral lower leg region coming in contact with boot-support-type leg holder Bel Flex® (Takara Belmont Corp., Osaka), which supports the left lower leg and foot was 26.3±7.9 mmHg. These results suggest that use of knee-crutch-type leg holder is more likely to induce common peroneal nerve palsy at the fibular head region, but use of boot-support-type leg holder dose not easily induce superficial peroneal nerve palsy at the lateral lower leg region, because capillary blood pressure is known to be 32 mmHg. Safer holders for positioning will be developed to prevent nerve palsy based on the analysis of chronological change in external pressure using BIG-MAT® system during anesthesia.