Blueprints Surgery, 5th Edition

Part V - Special Topics

Chapter 24

Plastic Surgery

Plastic and reconstructive surgery encompasses repair, reconstruction, and aesthetic improvement of bodily deformity resulting from congenital defects, posttraumatic tissue loss, and postablative defects, as well as overall enhancement in normal appearance. Reconstruc-tive surgeons seek to restore form and function while simultaneously achieving aesthetic normalcy. This chapter focuses on the principles of wound healing and tissue transfer.

THE RECONSTRUCTIVE LADDER

The principles of successful wound care include healing by primary or secondary intention, vacuum-assisted closure, skin grafts, local flaps, and distant flaps. A conceptual hierarchy has been established based on a reconstructive approach. The first principle of this approach is that wounds should be managed with the simplest technique to successfully heal a wound. (Fig. 24-1). A plastic surgeon is often consulted to determine which rung (technique) of the "reconstructive ladder" is appropriate from which reconstruction can proceed. Plastic surgeons perform reconstructive surgery in almost all areas of the body. Therefore, plastic and reconstructive surgery demands thorough understanding of anatomy. Individualized patient care is critical for successful reconstructive surgery. Two nearly identical wounds can have solutions that vary greatly in their technique yet adhere to plastic surgery principles.

PRIMARY CLOSURE

This is one of the simplest and most common methods of wound closure. Surgical wounds created at the time of an operation are usually closed primarily in a linear fashion. At the termination of a procedure, typically sutures, tissue glues, or metal staples are placed to align the wound edges. Different types of suturing techniques are frequently used, depending on the dimensions and specific characteristics of a wound (see Chapter 1, Surgical Techniques, Fig 1-6).

After ensuring complete hemostasis within the wound, the skin edges (if already sharply incised) are coapted in a tension-free manner. Sutures are carefully placed to evert the skin edges as this ensures proper healing. It is important to handle skin, dermis, and subcutaneous tissues gently during closure to prevent further inflammation and scarring. Healthy patients who suffer minimal tissue injury without significant skin or subcutaneous loss heal rapidly. Wounds that result from a sharp laceration generally heal faster and with less tissue edema than avulsion and crush injuries. It is important to distinguish how a wound has occurred. Reconstructive plans should be mindful of the mechanism of injury and what tissues are missing (e.g., skin, dermis, soft tissue, cartilage, bone, and so on). Thorough wound irrigation with sterile saline solution is essential before primary closure.

DELAYED PRIMARY CLOSURE

This method of closure is often chosen when a wound is contaminated, infected, or colonized by bacteria or when skin and soft tissue are missing such that the margins of the wound cannot be closed. Infected wounds with necrotic tissue or tissues heavily colonized with bacteria require sharp debridement followed by dressing changes. Wound care may

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be performed for several days to weeks. Wound contraction is a normal component of the healing process. This decreases the size and depth of wounds, enabling delayed primary closure. Wound contamination must be controlled before considering delayed primary closure. Closing a wound that is not clean results in the development of an infection with further delay to definitive wound healing.

SECONDARY INTENTION

Wounds with heavy bacterial contamination or tissue devitalization requiring debridement are often left open and unsutured. The bacterial burden upon the wound is reduced by sharp debridement so that wound edges are clean and optimized for healing. The defect created by serial debridement of nonviable tissue gradually fills with beefy red fibrovascular granulation tissue, which can contract and epithelialize over time to enable complete wound closure. A major recent advance is the use of the wound vacuum to speed healing. This device consists of a sponge attached to a suction machine. The sponge is placed in the wound bed attached to suction tubing, and an airtight seal is created over the assembly. Alterations of the microenvironment allow more rapid wound healing.

GRAFTS

When tissue loss prevents primary closure and waiting for a wound to heal by secondary intention will take months or potentially lead to wound infection, a skin graft is considered for wound closure. Skin grafting is a technique whereby skin is transferred from one area of the body to another. Most grafts are autografts (patient is both donor and recipient), although other types of grafts can be used in certain situations (isograft, allograft, or xenograft). Skin grafts lack an intrinsic blood supply. Therefore, the skin must become revascularized at the site of insertion, known as the recipient bed. Only vascularized beds are able to be covered with a skin graft. Once applied to a recipient bed, there are three phases of skin graft adherence. During the initial phase, the skin graft adheres as a result of fibrin deposition, known as plasmatic imbibition. The imbibition phase allows the skin graft to remain viable before being revascularized. This phase lasts approximately 48 hours. The second phase, called inosculation, involves anastomotic connections between the recipient bed and graft vessels. Simultaneously, capillaries from the recipient bed grow into the skin graft. Skin grafts are secured to the recipient bed with a bolster, preventing fluid accumulation and shearing between the undersurface of the graft and the wound bed. Other tissues can be used as grafts, such as cartilage, fat, nerve, bone, or tendon.

Skin is the most common tissue graft. Open wounds require barrier reconstitution to prevent bacterial invasion and fluid loss. Skin is collected as either split-thickness or full-thickness grafts.

Split-thickness skin grafts are thin sheets of skin collected from donor sites; they contain varying amounts of dermis and the overlying epidermis (Fig. 24-2). A skin graft can be meshed by creating many tiny incisions; this allows the graft to expand over a larger surface area and better conform to undulating surfaces. Meshed skin grafts also allow drainage of underlying

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wound exudates; however, as a disadvantage, they also leave large areas within the skin graft to heal by secondary intention. This leads to a cobblestone appearance and irregular contour. In contrast, a sheet (skin) graft often has a nicer aesthetic appearance but does not allow serum or blood to drain through it. Sheet graft survival relies solely on the recipient bed for successful adherence. Additionally, a sheet graft needs a larger donor site surface area for tissue collection. Because they are nonmeshed, sheet grafts contract considerably less than meshed grafts. The anterior thigh is a common donor site for skin graft tissue collection. Donor sites re-epithelialize from epithelial cells remaining within transected hair follicles and generally require 7 days to repopulate. Full-thickness skin grafts contain the entire dermis and epidermis. They are used to close surgical defects when durability, color match, appearance, and lack of wound contraction are required. The groin, flank, and postauricular area are common donor sites. Full-thickness donor sites require primary closure, whereas split-thickness skin grafts epithelialize (see Color Plate 18).

LOCAL FLAPS

Local flaps are blocks of tissue that maintain an intrinsic blood supply and are derived from tissue immediately adjacent to the recipient bed. A local tissue flap either advances (V-Y advancement flap, rectangular advancement flap; Fig. 24-3 and 24-5) or pivots (rotation flap or transposition flap; Fig. 24-4). It is important to distinguish and define a graft from a flap. A graft does not have its own blood supply, whereas a flap does (Fig 24-5A, B). When transferring a graft to cover a wound, it must be revascularized to survive. A flap is transferred to cover a defect with its blood supply intact.

When dealing with scar contracture that affects a patient's function and aesthetic appearance, plastic surgeons can use the Z-plasty technique to lengthen and alter the direction of the scar. A Z-plasty uses two opposing transposition flaps that switch places and gain length along the central axis of the original scar. Skin and tissue adjacent to the transposed flaps are recruited to lengthen and blend the scar with the surrounding tissues. A Z-plasty changes the direction of the central limb of scar by 90 degrees (Fig. 24-6). This technique improves the contour and aesthetic appearance of scars by camouflage. Scars become softer and less pigmented once tension is relieved via

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a Z-plasty. The actual gain in scar length depends on the angle of the flaps, the length of the central limb, and the quality of the surrounding tissues.

REGIONAL FLAPS

When adjacent tissue is inadequate, a flap is raised from a distant location and inset for wound closure. Flaps include adipocutaneous, fasciocutaneous, myocutaneous, osteocutaneous, or muscular flaps (Figs. 24-7 and 24-8). Flaps that are interpolated over cutaneous skin require pedicle transection once the flap becomes vascularized from the recipient tissue bed. The classic operation of this type is the Tagliacotian operation—devised by the Italian surgeon Gasparo Tagliacozzi (1546 to 1599)—in which a forearm flap is transferred to the nose (Italian rhinoplasty). Other examples are groin flaps to the hand and cross leg flaps. Prolonged awkward positioning is often required postoperatively until the pedicle is eventually transected.

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A common pedicled musculocutaneous flap used for breast reconstruction is the transverse rectus abdominis myocutaneous flap. The contralateral rectus abdominis muscle is mobilized, with the superior epigastric artery left intact to supply the large attached skin paddle. The bulky paddle and muscle pedicle are tunneled superiorly and inserted into the breast defect, while the abdominal donor site is closed (abdominoplasty; Fig. 24-9).

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TISSUE EXPANSION

Tissue expanders are placed beneath the dermis in a subcutaneous pocket. Their purpose is generally to recruit skin. This is achieved via gradual expander inflation over weeks to months to expand the skin superficial to the expander. The creation of additional skin surface area can be used for breast reconstruction, scalp reconstruction, or any defect requiring local tissue transfer (Fig. 24-10). Benefits of tissue expansion include good skin color match, as well as preservation of hair and sensation. Tissue expansion can be complicated by pain, infection, and contour deformity of surrounding structures.

FREE TISSUE TRANSFER

Free tissue transfer is used to reconstruct defects lacking local and regional pedicle flap options. Advances in microsurgery have enabled distant tissue transfer to become a reliable and predictable reconstructive option. Tissue (i.e., skin, subcutaneous fat, and muscle) can be transferred to a distant site based on its feeding nutrient artery. The free flap is collected from a distant donor site to cover a complex wound often with exposed vessels, bone, or other critical structures. The arterial blood supply and vena comitantes of a free flap are coapted to a target artery and vein within or adjacent to the defect using microvascular techniques (Figs 24-11A, B, and C).

KEY POINTS

• Goals of plastic surgery are to restore form and maximize function.
• Complex wounds require thoughtful individualized solutions.
• Methods of wound closure are based on the principles of the reconstructive ladder.
• Grafts do not have a blood supply; they become vascularized from a recipient bed.
• A flap has its own blood supply, generally rotated or advanced into complex wounds.
• Free tissue transfer involves collection of a distant flap with its arterial and venous vessels.