The mobilization of soft tissues to reconstruct cutaneous operative wounds is more than just an exercise in geometry.1 Instead, reconstructive procedures involve the manipulation of biologic tissues with the primary purpose being an approximation of the preoperative state of “normalcy.” The mystical attainment of an invisible scar and a complete restoration of the presurgical condition is a worthwhile goal that can be closely approximated—even if perfection is unattainable. The degree to which a minimally perceived result is approached is dependent on a number of biologic factors beyond the surgeon’s control. These include the patient’s age and general health, the long-term use of certain medications, whether or not the patient smokes, and a number of uncontrollable cutaneous variables such as skin thickness, sebaceous quality, pigmentation, elasticity, actinic damage, prior surgical scarring, and individual variations in scar formation.
Many mechanical tissue parameters are amenable to manipulation. The interaction of the intrinsic biologic properties and the mechanical operations performed on tissues may be aptly described as the biomechanical aspects of wound closure.2–4 The biology of tissue is a major determinant of its ability to move. This is readily observed in the skin tension lines on the face, where closure in one direction is facile, and perpendicular closure is challenging.5 The response of tissue during reconstruction involves both intrinsic biologic and mechanical properties and the physics of forces and motion. Knowledge of the mechanics of reconstruction augments the surgeon’s ability to design an appropriate wound closure. The limiting biologic properties dictate the available menu of reconstructive designs available for wound closure. Concepts that seem simple and intuitive often have hidden complexity that in select instances become important in optimizing the final closure result. The goals of a successful reconstruction procedure can be arbitrarily divided along biologic and mechanical lines, and each plays an important role in a successful reconstruction.
The mechanical plan of tissue movement is designed to achieve a closure: (1) under minimal tension; (2) without distortion of critical anatomic structures and landmarks such as the lip, nasal rim, eyebrow, and hairline; (3) using skin of matching pigment and texture to the affected region; and (4) with consideration to optimal placement of scars along cosmetic unit junctions. The mechanical reconstructive design is therefore implemented in an attempt to reestablish an aesthetic and functional baseline.
The biologic considerations to tissue movement involve: (1) maintenance of the viability of mobilized tissues; (2) preservation of sensory and motor innervation; (3) appropriate mobilization of tissues to allow for wound closure; and (4) prevention of morbidity such as hematoma, infection, and dehiscence. In order to understand macrobiomechanical concepts, an anatomic model for facial surgery will first be introduced.6 This will be followed by a discussion of the manipulations used to modulate or decrease tension, redistribute tension vectors, and to reposition redundant tissue. Jointly, these topics are the crux of clinical biomechanics, as they pertain to successful ...