Effects of lithotomy position and external compression on lower leg musclecompartment pressure

Background Case reports have suggested that externally applied pressure fro m antithrombosis devices may contribute to the development of compartment s yndromes during extended surgery in the lithotomy position. The purpose of this study was to assess the effects of a pneumatic compression device on d irectly measured intracompartment pressure in the lower leg with the leg po sitioned in the lithotomy position. Methods: In 25 conscious, healthy men and women, the authors measured press ure within the tibialis anterior muscle compartment with the leg supine and in the lithotomy position with and without intermittent compression. Three different devices were used to keep the leg in the lithotomy position, sup porting the leg either behind the knee, under the calf, or at the ankle. Results: The lithotomy position with support behind the calf or knee increa sed intracompartment pressure to 16.5 +/- 3.4 versus 10.7 +/- 5.8 mmHg supi ne (mean +/- SD; P < 0.05). The addition of intermittent compression decrea sed pressure to 13.4 +/- 5.1 mmHg during lithotomy (P < 0.05) and to 9.1 +/ - 7.0 mmHg in the supine position (P < 0.05). In contrast, the lithotomy po sition with support near the ankle decreased intracompartment pressure to 8 .7 +/- 5.6 versus 13.3 +/- 5.1 mmHg supine (P < 0.05). The addition of inte rmittent compression decreased pressure to 6.5 +/- 5.4 mmHg during lithotom y (P < 0.05) and to 10.3 +/- 4.7 mmHg in the supine position (P < 0.05). Conclusions: These results show that the lithotomy position is associated w ith changes in intracompartment pressure that are dependent on the method o f leg support used. Furthermore, they indicate that Intermittent external c ompression can reduce intracompartment pressure in the lower leg. Therefore , increases in intracompartment pressure during surgery in the lithotomy po sition with the calf or knee supported may be one of the factors that contr ibute to the development of compartment syndrome. Further, use of intermitt ent external compression may significantly reduce this pressure increase.