This chapter presents a basic overview of the approach to reconstruction of cutaneous facial defects with local skin flaps. Emphasis is placed on the understanding of the anatomy, evaluation of a defect, and design of an appropriate local skin flap.

Essentials of Diagnosis

For successful local flap reconstruction of facial defects, the surgeon must have a thorough understanding of thefollowing.

• Biomechanics of soft tissues
  
• Vascular supply to the face and given skin flap
  
• Aesthetic subunits and the relaxed skin tension lines of the face (RSTL)
  
• Dimensions and depth of the defect
  
• Inherent structural characteristics of the native skin in the area of the defect (ie, thickness and sebaceous character).

Successful reconstruction of facial defects requires a thorough understanding of skin anatomy and physiology, careful analysis of the defect, and meticulous soft tissue techniques. Options for reconstruction should generally proceed from least invasive to most invasive in terms of morbidity. This approach is termed the “reconstructive ladder.” Most facial defects that are too large for primary closure are amenable to local flaps. When planned and executed properly, local flaps allow for rapid reconstruction with a reliable blood supply, minimal morbidity, and excellent cosmesis. This chapter reviews the classification of commonly used local skin flaps and outlines the use of local flaps for facial reconstruction. In considering the appropriate surgical approach for a given defect, the surgeon should not forget that secondary intention healing is a viable option for concave areas of the face.

When possible, local flaps should be designed in the same aesthetic unit as the initial defect. Lines of excision should usually be made parallel to relaxed skin tension lines (RSTL) or along aesthetic borders to optimize scar camouflage. If the defect involves multiple aesthetic subunits, it may be necessary to use a separate flap for each subunit. If more than 50% of a subunit is involved, the defect may be enlarged to reconstruct the entire unit with a flap. Placing incisions parallel to RSTLs reduces tension on wound closure by placing maximal tension into lines of maximal extensibility (LME). Skin tension and its distribution are important to avoid distortion of key facial landmarks such as the eyelid, lip, and the nasal ala.

Local skin flaps can be classified either by their blood supply or by the method of transfer. (Table 77–1)

Flap Blood Supply

Surgeons must be familiar with the vascular supply of a local flap, either random (supplied by the dermal and subdermal vascular plexuses) or axial (supplied by a named artery and vein). Most axial flaps have some random blood supply at their distal ends.

The blood supply to a random skin flap is derived from musculocutaneous perforating arteries near the base of the flap. The distal portion of the flap is perfused by interconnecting subdermal plexuses located at the junction between the deep reticular dermis and subcutaneous fat. These vessels communicate with more superficial dermal plexuses located at the papillary ridge to the dermal–epidermal junction. Rhombic and bilobed flaps are examples of random pattern flaps.

Axial (arterial) pattern skin flaps are perfused by a direct cutaneous artery within the longitudinal axis of the flap. Axial flaps typically have improved survival lengths compared to random pattern flaps due to this vascular supply. The surviving length of axial flaps is related to the length of the cutaneous artery. Flap necrosis secondary to ischemia can occur at the distal portion of the flap if the length exceeds the arterial length, where the flap is dependent on random pattern blood supply. A common example of an axial flap is the paramedian forehead flap, which is supplied by the supratrochlear artery.

This chapter will classify local flaps according to classic transfer methods. In reality, many local flaps actually are combinations of these classifications.

Advancement Flaps

Advancement flaps have a linear configuration where an adjacent tissue is advanced linearly to cover a primary tissue defect. Advancement flaps are subclassified as simple, single pedicle, bipedicle, and V–Y flaps. These flaps are particularly useful in reconstructing forehead, lip, and eyelid defects.