Optimal Patterns for Suturing

A mathematical model for computing stresses in sutured human skin wounds is presented. The model uses the incremental law of elasticity and elastic constants valid for in vivo orthotropic skin. The model is applied to compute the principal stress and displacements resulting from suturing small elliptical and circular wounds in a large at sheet of skin, in order to determine the optimal suturing patterns. It is observed that the average stress index for a circular wound sutured toward the center is almost double that of a wound sutured perpendicular to a diameter. Thus, the latter type of suturing pattern is preferable. Similarly, suturing an elliptical wound perpendicular to its major axis produces a lower average stress index than a circular wound of the same area. It is also found that the optimal ratio of semi-major to semi-minor axis of an elliptical wound is near 3 (for abdomenal wounds), i.e., this ratio produces the most uniform stresses along the wound edges, where wound healing is the lowest. Since high stresses have adverse eeects on healing and blood ow, this work, depicting regions of high stresses, may be used along with other biological factors to help predict regions of slower healing in sutured wounds.