Male sex, height, weight, and body mass index can increase external pressure to calf region using knee-crutch-type leg holder system in lithotomy position

Abstract

Background: Well-leg compartment syndrome (WLCS) is one of the catastrophic complications related to prolonged surgical procedures performed in the lithotomy position, using a knee-crutch-type leg holder (KCLH) system, to support the popliteal fossae and calf regions. Obesity has been implicated as a risk factor in the lithotomy position-related WLCS during surgery. In the present study, we investigated the relationship between the external pressure (EP) applied to the calf region using a KCLH system in the lithotomy position and selected physical characteristics.

Methods: Twenty-one young, healthy volunteers (21.4±0.5 years of age, eleven males and ten females) participated in this study. The KCLH system used was Knee Crutch(®). We assessed four types of EPs applied to the calf region: box pressure, peak box pressure, contact pressure, and peak contact pressure, using pressure-distribution measurement system (BIG-MAT(®)). Relationships between these four EPs to the calf regions of both lower legs and a series of physical characteristics (sex, height, weight, and body mass index [BMI]) were analyzed.

Results: All four EPs applied to the bilateral calf regions were higher in males than in females. For all subjects, significant positive correlations were observed between all four EPs and height, weight, and BMI.

Conclusion: EP applied to the calf region is higher in males than in females when the subject is supported by a KCLH system in the lithotomy position. In addition, EP increases with the increase in height, weight, and BMI. Therefore, male sex, height, weight, and BMI may contribute to the risk of inducing WLCS.

Keywords: obesity; peak contact pressure; physical characteristics; pressure-distribution measurement system; well-leg compartment syndrome.

Figure 1

Lithotomy position. Note: The subject’s left knee and lower leg were placed on a BIG-MAT2000P3BS^® sheet spread over a Knee Crutch^®.

Figure 2

Representative pressure-distribution view at the surface of the left popliteal fossa and calf region in contact with the left Knee Crutch^® measured using the BIG-MAT^® system in the lithotomy position. Notes: High-pressure areas are shown with red squares, while low-pressure areas are shown with blue squares. The dotted-line square box shows the left calf region.

Figure 3

Relationship between peak contact pressure (PCP) to the calf region and the physical characteristics of all subjects using the Knee Crutch^® in the lithotomy position. Notes: Circles and triangles show PCP to the right and left calf regions, respectively. Solid, dashed, and dotted simple regression linear lines show relationships between PCP to the bilateral, right, and left calf regions and three physical characteristics of the subjects (height, weight, or body mass index [BMI]). (A) Height: solid line, PCP (mmHg) =1.88× height (cm) −256 (r=0.51, P=0.001); dashed line, PCP (mmHg) =2.05× height (cm) −281 (r=0.47, P=0.031); and dotted line, PCP (mmHg) =1.71× height (cm) −232 (r=0.60, P=0.004). (B) Weight: solid line, PCP (mmHg) =1.54× weight (kg) −34.9 (r=0.53, P=0.000); dashed line, PCP (mmHg) =1.64× weight (kg) −36.5 (r=0.48, P=0.026); and dotted line, PCP (mmHg) =1.44× weight (kg) −33.4 (r=0.65, P=0.001). (C) BMI: solid line, PCP (mmHg) =4.85× BMI (kg/m²) −45.5 (r=0.40, P=0.009); dashed line, PCP (mmHg) =5.21× BMI (kg/m²) −48.6 (r=0.36, P=0.107); and dotted line, PCP (mmHg) =4.48× BMI (kg/m²) −42.3 (r=0.48, P=0.028).