Studies of the excisional wound: I. Biomechanical effects of undermining and wound orientation on closing tension and work.

In experimental in vivo studies on pigs, objective mechanical measurements of the physical characteristics of skin in excisional wound margins demonstrated that wound orientation relative to the skin-tension lines and wound location causes significant variance in the force and work required for closure, amount of retraction occuring in each margin, and effects of undermining on wound closure. Wounds parallel to the tension lines require less force and work to close initially, retract less with the initial excision, and benefit more from undermining than similar wound oriented perpendicularly to the tension lines. To minimize tension on the closure, awareness of the variable effects of undermining on the two margins of a wound and on wound in different locations and orientation is important in planning flaps, scar revision, and excision of lesions.