Lower leg blood pressure decreases while calf external pressure increases with the angulation of the Trendelenburg position in the lithotomy position with calf- and foot-supported leg holders.

Patients who underwent lower abdominopelvic surgeries in the lithotomy position (LP) and the Trendelenburg position (TP) with the leg holder are at risk of developing well leg compartment syndrome (WLCS). However, contributing factors related to the LP with TP associated with WLCS are unknown. This study aimed to investigate the associations between external pressure at the calf in the LPs at different angulations of the TP and physiological characteristics. Eighty-four university students (age, 21.7 ± 0.9; 42 men and 42 women) voluntarily participated in the study. The awake participants were placed in the LPs using the calf- and foot-supported leg holder at 0° (horizontal level), 5°, 10°, and 20° head-down tilts by moving the electric operating table. The peak contact pressure (pCP) was measured at the calf as a representative external pressure using the pressure distribution measurement system BIG-MAT®. Lower leg blood pressure significantly decreased with TP angulation, while calf pCP significantly increased with it at 0°, 5°, 10°, and 20° head-down tilts (39.4 ± 15.2, 46.5 ± 17.7, 47.2 ± 16.9, and 50.3 ± 17.6 mmHg, respectively). The calf pCP with a 10° head-down tilt was correlated positively with the calf total force (P < 0.001) and negatively with the calf contact area (P < 0.001). Blood hypoperfusion due to low lower leg blood pressure secondary to lower leg elevation and head-down tilt, and high calf external pressure due to direct external compression from the leg holder where it is loaded may contribute to WLCS.