Correlation of cutaneous tension distribution and tissue oxygenation with acute external tissue expansion

Abstract

Today, the biomechanical fundamentals of skin expansion are based on viscoelastic models of the skin. Although many studies have been conducted in vitro, analyses performed in vivo are rare. Here, we present in vivo measurements of the expansion at the skin surface as well as measurement of the corresponding intracutaneous oxygen partial pressure. In our study the average skin stretching was 24%, with a standard deviation of 11%, excluding age or gender dependency. The measurement of intracutaneous oxygen partial pressure produced strong inter-individual fluctuations, including initial values at the beginning of the measurement, as well as varying individual patient reactions to expansion of the skin. Taken together, we propose that even large defect wounds can be closed successfully using the mass displacement caused by expansion especially in areas where soft, voluminous tissue layers are present.

Figure 1

Placement of the oxygen measuring probe in relation to the hook system (f = force).

Figure 2

Experimental setup on a patient in the operating room.

Figure 3

Experimental setup for measurement of skin expansion.

Figure 4

Tension calculation at force F (F0), diameter Q (Q₀), length L (L0), and with initial values in parentheses.

Figure 5

Mean value (MV) and standard deviation (STD) of the wound edge movement as a factor of the force F at the wound edge.

Figure 6

Mean normalized skin expansion as a factor of the distance from the wound edge and the force F at the wound edge.

Figure 7

Mean expansion over force F. Insert: Allocation of the individual test curves to the respective distances from the wound edge.

Figure 8

Normalized oxygen partial pressure pO2 over force F.