In vivo muscle stiffening under bone compression promotes deep pressure sores.

摘要: Pressure sores (PS) in deep muscles are potentially fatal and considered one of the most costly complications spinal cord injury patients. We hypothesize that continuous compression longissimus gluteus by sacral ischial bones during wheelchair sitting increases muscle stiffness around bone-muscle interface over time, thereby causing to bear intensified stresses relentlessly widening regions, a positive-feedback spiral. In this study, we measured long-term shear moduli tissue vivo rats after applying (35 KPa or 70 for 1/4-2 h, N = 32), evaluated viability matched groups (using phosphotungstic acid hematoxylin histology, 10). found significant (1.8-fold 3.3-fold, p < 0.05) stiffening subjected 35 30 min over, 15 over. By incorporating effect into finite element (FE) model buttocks user identified mechanical stress wave which spreads from outward through tissue. After 4 h FE simulated motionlessness, 50%-60% cross section was exposed compressive (shown induce cell death rat within min). During these mean across transverse increased 30%-40%. The identification stiffening-stress-cell-death spiral developing initial motionless provides new mechanistic insight PS formation calls reevaluation 1 repositioning cycle recommended U.S. Department Health.