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Random pattern flaps are an indispensable reconstruction option for closure of wounds which may not be suitable for healing by second intention or repair with a linear closure. Defects too large to close in a side-to-side fashion may be ideally suited for such flaps, which are recruited from adjacent tissue reservoirs and use tissue with a similar skin match. When second intention healing or linear closure may result in distortion of free margins, well-designed random pattern flaps can be helpful in redirecting and redistributing tension vectors and allow incision lines to be hidden along cosmetic boundaries and relaxed skin tension lines.

Random pattern flaps are so named because their blood supply is not based on a single vessel, but on the “random” albeit copious subdermal plexus. Advancement, rotation, and transposition flaps are all types of random pattern flaps, each named based on the type of movement the flap undergoes (Table 18-1). Advancement flaps slide in a straight line from the donor site to the recipient site. Rotation flaps rotate in an arc about a pivot point. Transposition flaps move from the donor site to the defect over a peninsula of uninvolved intervening skin.

TABLE 18-1Classification of Surgical Flaps


Prior to any reconstruction, the surgeon must ensure that complete tumor clearance has been obtained. The goal of a well-designed repair is to optimize functional and aesthetic outcomes. During flap design, one must identify a donor site or tissue reservoir – ideally with a color, texture, and thickness similar to that of the defect. Incision lines should be drawn along relaxed skin tension lines, and boundaries between cosmetic units should be maintained. Generous undermining is often needed for proper mobilization, but care must be taken to perform it in the proper plane (Table 18-2) and in such a way as to minimize unnecessary vascular trauma. Movement of the flap should create minimal tension and virtually imperceptible distortion of surrounding structures.

TABLE 18-2Plane of Undermining based on Location

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