Mechanism of Origin of Positive Tissue Pressure During Negative-Pressure Wound Therapy.

This report provides a simplified insight into the previously unexplained physical mechanism of the origin of local positive tissue pressure during negative-pressure wound therapy (NPWT). A chain of 2 spring model could be used to show the biomechanical interaction between the NPWT dressing and the adjacent body tissues. It is important to assume that the application of NPWT dressing to the body surface creates a new closed compartmentalized volume. Air suction generates local positive pressure within the dressing due to unopposed atmospheric load, which in turn leads to compression of the adjacent tissues and induction of positive pressure there. Analysis of the biomechanical events during NPWT implies the possibility of tissue injury by positive pressure and suggests clinical alertness in regard to the balance between the size of the NPWT dressing and suction pressure as well as further related research.