Master Techniques in Otolaryngology - Head and Neck Surgery: Reconstructive Surgery, 1ed.

39. Reconstruction of the Lateral Skin Defect

Frederic W.-B. Deleyiannis

INTRODUCTION

Defects of the skin involving the lateral neck and/or scalp present a challenge to the reconstructive surgeon that begins with addressing the question of whether the expected defect can be treated in a staged, reconstructive approach or whether an immediate, single-stage reconstruction is the primary priority. Staged reconstruction often provides the optimal method of reconstruction since tissue expansion can be used to expand regional flaps/tissue to replace the missing skin or scalp with similar, regional tissue. When acute coverage is needed, skin grafts and regional flaps are available depending on the site of the defect, the available blood supply, and the underlying structures that are exposed after the resection such as exposed bone, periosteum, and the great vessels. Free flaps, in particular the anterolateral thigh free flap, are often the first choice for large defects of the lateral neck (Fig. 39.1). This chapter focuses on the selection of regional flaps, particularly combined with tissue expansion, for the reconstruction of lateral neck and scalp defects. The morbidity of regional flaps is also considered, especially in regard to the creation of donor site scars (i.e., alopecia) and donor defects. The potential complications associated with tissue expansion are also discussed.

FIGURE 39.1 Lateral neck reconstruction with an anterolateral thigh free flap. A. A 17-year-old male with melanoma. B. Planned skin resection. C. Resection. D. Reconstruction with anterolateral free flap.

The majority of defects involving loss of the skin of the neck or scalp are usually the result of the resection of cancers of the skin, trauma, or burns. For cancer of the skin, reconstruction is initiated once surgical margins are clear. This often can be accomplished in a delayed manner, such as within a few days after Mohs surgery, or more immediately in the operating room after frozen sections are negative. Traumatic loss of the scalp, unless the underlying dura is exposed, should be reconstructed with the goals of minimizing the number of scalp incisions, creating a stable wound that will allow eventual expansion of the scalp tissue, and placing any incisions necessary for acute coverage so that they do not interfere with the blood supply of regional flaps (Fig. 39.2) or the secondary placement of tissue expanders. Prior radiation therapy to the surgical field can negatively affect local wound healing. Thus, in addition to understanding the TNM stage of the cancer, the surgeon should obtain the history of any previous treatment with radiation therapy and anticipate the possible need for postoperative radiation therapy.

FIGURE 39.2 Regional blood supply for scalp reconstruction. Scalp flaps should be designed to capture regional axial blood supply in their base. Optimal, secondary reconstruction usually requires tissue expansion.

The physical examination should focus on defining the extent of the defect. The following questions should be addressed:

• What are the expected dimensions (i.e., surface area and volume) of the defect?

• What critical underlying structure will be exposed (i.e., bone, periosteum, vessels, facial nerve)?

• What regional blood supply will remain after the resection (i.e., what identifiable arteries will be resected, such as the superficial temporal, supraorbital, facial artery) that would support regional flaps?

• Will a neck dissection be needed, and if so, where will the incisions for the neck dissection be placed so that they do not interfere with flap design?

The indications for reconstruction of the lateral neck defect are any defect that cannot be closed primarily or where the risk of skin breakdown and great vessel exposure is significant.

Free tissue transfer is often a better choice for reconstruction if the surgical site has received prior radiation. Comorbidities, such as severe cardiovascular or peripheral vascular disease, may guide one to choose a regional flap instead of a microvascular flap. Transposing or rotating regional flaps that have been previously in an irradiated field likely place the reconstruction at risk for wound dehiscence. In a similar manner, if a surgical extirpative site is expected to receive postoperative radiation therapy, regional flaps or free flaps (vs. the use of skin graft) likely reduce the risk of osteoradionecrosis since the bone is being covered with well-vascularized tissue.

Once the extent of the expected defect has been anticipated and defined, preoperative planning now involves determining the various ways to reconstruct the defect with an understanding of the respective requirements, advantages, and disadvantages of each method (Table 39.1). Whether the defect is caused by a malignant lesion (i.e., cancer of the skin), a benign lesion (i.e., nevus), or a traumatic injury will also affect the choice of reconstruction. Methods of reconstruction will include staged excisions, adjacent tissue transfer (i.e., rotation–advancement flaps with a random blood supply), regional flaps, regional flaps combined with tissue expansion, and free flaps. To ensure the greatest vascularity, one should design the chosen regional flap so that its base contains a regional artery. This can be confirmed with a Doppler examination if there is any doubt about the regional blood supply.

TABLE 39.1 Methods of Reconstruction

Staged Excisions

Staged excisions are most suited for large benign lesions, usually congenital nevi, of the neck or scalp. The first surgery involves removing approximately 60% to 80% of the original lesion and placing the entire excision within the borders of the original lesion. For lesions of the neck, one should try to place the final orientation of the scar in a natural skin crease (Fig. 39.3). After the first surgery, some spreading of the scar can be expected.

FIGURE 39.3 Staged neck excision. A. Vertically oriented nevus to be excised in stages. The goal is to place the final closure in a natural skin crease. B. First stage. C. Six months after first stage. D. One month after second stage.

The advantages of a staged excision should be compared to the possibility of doing tissue expansion. Many staged excisions of lesions of the scalp will be associated with some scar alopecia at the closure site. Thus, tissue expansion is often offered as an additional way to remove the lesion with the possibility of less scar spreading. However, expansion requires approximately 2 to 3 months between surgeries while the expander is being inflated, and some patients either do not want or cannot make weekly appointments for expansions.

Skin Grafts

Skin graft reconstruction of the neck or lateral scalp is usually done only as a temporizing measure. Skin grafts are placed acutely with the goal of creating a healed wound but with the long-term expectation that they will be removed and replaced with local tissue (Fig. 39.4). Grafts are usually harvested as split-thickness grafts with an approximate thickness of 0.014 inch in adults. In children, grafts are thinner with thicknesses that ranging from 0.008 to 0.014 inch. Because of the similar color match, the scalp is an excellent source of skin grafts for the face or neck. Skin grafts must be placed on an underlying bed of well-vascularized tissue. Periosteum will support a split-thickness skin graft. Cranial bone must be partially decorticated to allow granulation prior to placing a skin graft. A vacuum-assisted closure (VAC) can be used to promote granulation tissue prior to placing a skin graft (Fig. 39.4). For scalp defects once the skin graft has healed and there is no longer an open wound, tissue expanders are placed with the goal of replacing the skin grafts with the surrounding scalp once it has been expanded.

FIGURE 39.4 Multistage scalp reconstruction with skin grafts, VAC, and expanded scalp flaps. A. Full-thickness burn of lateral scalp to bone. B. Outer table drilled to allow cortical bleeding. C. VAC in place. D. Three weeks of VAC therapy. E. One week after split thickness skin graft. F. Tissue expander to be placed with template. G. After 2 months of expansion. H. Tissue expander removed with scalp flap raised. I. Scalp flap rotated to replace excised skin graft. J. Lateral view, 3 years postinjury. K. Posterior view, 3 years postinjury.

Regional Flaps

Regional flaps of the lateral skull are designed on the regional blood supply, in particular the supraorbital, superficial temporal, and/or postauricular artery (Fig. 39.2). These are rotation–advancement or transposition flaps that are designed to cover the defect. At the same time, their movement often leaves a donor defect that needs skin grafting (Fig. 39.5). Large, overlapping scalp flaps, such as “pinwheel” or “banana peel” (Orticochea flaps), require undermining most of the scalp and incising large areas of scalp. Defects can be closed with these flaps, but large areas of scar alopecia may also be a long-term outcome (Fig. 39.6). Figures 39.5 and 39.6 demonstrate two patients immediately closed with scalp flaps. In each case, the scalp wound was acutely closed, but these cases also demonstrate the potential morbidity of the donor defect created by the transposition or rotation of scalp flaps.

FIGURE 39.5 Anterior scalp with donor site. A. Exposed craniotomy burr hole after resection of a squamous cell carcinoma. B. Anteriorly based scalp flap raised to cover defect/burr hole. C. Donor site closed with skin graft. D. One year after reconstruction with skin graft.

FIGURE 39.6 Alopecia after scalp rotation flaps. Vertex and parietal scar alopecia after raising two large (pinwheel) scalp flaps to close an area of excised cutis aplasia.

Other pedicled flaps, such as the lower trapezius island musculocutaneous flap, can reach posterior and lateral scalp defects. The flap may be mobilized by pedicling it solely on the transverse cervical artery and vein. The arc of rotation may be increased by placing the skin paddle more caudal. If the skin paddle of the flap is placed over the lower portion of the trapezius and within the territory of the latissimus, then the dorsal scapular artery and vein should be preserved. The dorsal scapula artery and vein pass between the rhomboid minor and major to supply the caudal portion of the trapezius muscle. Trapezius flaps have a number of relative disadvantages. These include potential loss of the spinal accessory nerve, inability to use these flaps if the transverse cervical artery has been sacrificed in a neck dissection, the occasional need to skin graft the donor site, and special positioning to harvest the flap. The use of trapezius flaps has almost been completely replaced by fasciocutaneous free flaps, in particular the anterolateral thigh free flap (Fig. 39.1).

Regional flaps for lateral and posterior–lateral neck reconstruction primarily consist of pectoralis, cervicodeltopectoral (CDP), deltopectoral, and pedicled scapular flaps. The pectoralis major myocutaneous (PMM) flap is the most frequently used myocutaneous flap in head and neck reconstruction. The blood supply of the PMM flap is provided by the lateral thoracic artery and the pectoral branch from the thoracoacromial artery, a branch of the subclavian artery. The pectoral branch passes deep to the clavicle through the clavipectoral fascia at approximately the junction of the medial two-thirds with the lateral one-third. It then takes an oblique course deep to the pectoralis muscle and gives off muscular branches that supply the muscle and pierce the muscle to supply the overlying skin.

The PMM flap should be designed on the anterior chest wall to conform to the size and shape of the defect. To ensure that the length of the musculovascular bundle will be adequate to reach into the oral cavity, one should fabricate a template of the flap with surgical towel cut to the anticipated size and length. The point of rotation of the flap can be designed as superior as the point of exit under the inferior edge of the clavicle of the pectoral branch of the thoracoacromial artery. If the PMM flap is to be mobilized this far superiorly, the lateral thoracic artery must be divided. This may compromise the blood supply of the flap in some patients. Under most circumstances, the PMM flap begins at the level of the nipple and is carried inferiorly to the lower borders of the rib. The skin paddle may be extended over the rectus sheath, but these portions of skin are supplied by a random vascular pattern and are less reliable. After the incisions around the skin paddle are carried through the subcutaneous tissue, the muscle is incised medially from its sternal attachments and elevated off of the chest wall. The neurovascular bundle is identified by direct visualization and palpation. For further mobilization, the humeral attachments of the muscle are divided. An oblique incision from the superior, lateral edge of the skin paddle to the axillae can be used to improve exposure. This incision should be located approximately at the site of an inferior transverse incision that would be used if a deltopectoral flap was being designed. By not dividing the second and third intercostals perforators when raising the PMM flaps and by not incising the skin supplied by the second and third intercostals perforators, one still has the future option of using an ipsilateral deltopectoral flap. The donor area from the PMM flap can be closed primarily, leaving little chest deformity. The pectoralis muscle can be employed without the cutaneous portion of the paddle. In this way, the flap is far less bulky. A split-thickness skin graft can be applied directly to the muscle.

My approach for a CDP flap begins with marking the skin resection for tumor removal in conjunction with the neck incision used for the anticipated neck dissection so that the neck incisions used by the ablative surgeon will not disrupt the design of a CDP flap (Fig. 39.7). A standard transverse neck incision may prevent incorporation of the cervical component of the CDP flap. In the neck, the incisions for the CDP flap typically follow the anterior border of the trapezius muscle and proceed laterally to medially on the chest below the third intercostal perforator from the internal maxillary artery (the traditional site of the inferior chest wall incision of the deltopectoral flap). The entire skin island between the inferior aspect of the defect and the chest wall incision is transferred in continuity. The use of CDP flap for lower face or neck reconstruction provides for a better skin quality match compared to a distant or free flap. My decision to use a CDP flap versus a pectoralis myocutaneous flap is based mainly on preoperative planning by marking the anticipated skin defect and determining with a surgical towel cut into a template of the CDP flap whether the flap will rotate sufficiently to close the defect. By placing the skin island of a pectoralis flap inferior to or in continuity with the chest wall incision of the CDP flap and by preserving the second and third intercostal perforators during the pectoralis flap harvest, one can safely raise both a CDP and pectoralis flap (Figs. 39.7 and 39.8).

FIGURE 39.7 Design of CDP and pectoralis flaps. Skin incisions for CDP and pectoralis major flaps. The defect includes a cutaneous, cervical resection. Lower left: closure with a PMM flap; Lower right: closure with CDP flap.

FIGURE 39.8 Cheek and lateral neck reconstruction with a CDP and pectoralis flap. A. Resection of skin, parotid, and lateral mandible for cancer of the parotid gland. B. CDP flap raised; blood supply from internal mammary artery perforators. C. Inset of pectoralis muscle flap; skin paddle removed; adipose tissue and muscle of flap provide bulk restoration for the cheek. D. Closure with rotation of the CDP over the pectoralis flap.

The branching pattern of the circumflex scapular artery and vein permits the harvest of a number of fasciocutaneous flaps. The scapular flap is based on the horizontal cutaneous branch of the circumflex scapular artery. The parascapular flap is based on the descending cutaneous branch of the circumflex scapular artery. These flaps are routinely harvested as free flaps, but they can also be used as pedicled flaps for posterior–lateral neck defects, especially if they are tissue expanded prior to their transposition. Figure 39.9 demonstrates one such case where a preexpanded scapular flap was combined with a preexpanded deltopectoral flap for a large posterior–lateral neck defect. First, a deltopectoral flap was designed on the right chest; Doppler ultrasound was used to identify the internal mammary perforators between the second and third intercostal spaces. Back cuts were then made along the deltopectoral groove and along the anterior aspect to where the expander capsule was located. This allowed the flap to rotate 90 degrees and to close the neck defect anteriorly and laterally to the level of the trapezius muscle. The patient was then placed in the left lateral decubitus position, and the scapular flap was designed. Doppler ultrasound was used to identify the circumflex scapular artery in the triangular fossa. A large pedicled, scapular fasciocutaneous flap was then raised. A back cut along the rim of the capsule of the expander extending to the posterior axillary line allowed the flap to rotate 90 degrees to close the remaining defect. All donor sites were then closed primarily.

FIGURE 39.9 Tissue expansion of deltopectoral and scapular flaps. A. Five-year-old with massive dermatofibrosarcoma. The expected resection of neck skin, platysma, and trapezius fascia is outlined. B. Expanded deltopectoral flap. C. Expanded, pedicled scapular flap. D. Tissue expander removed deltopectoral flap being rotated. E. Scapular flap being rotated. F. Six weeks post-op: posterior view. G. Six weeks post-op: lateral view. H. Six weeks post-op: anterior view.

Tissue Expansion

Tissue expansion allows for adjacent transfer of sensate tissue to repair defects while maintaining skin color and texture. In 2004, Hurvitz et al. reviewed pediatric cervicofacial tissue expansion and showed an overall complication rate of 30.8% with the highest complication rate affecting the neck area. Previous studies have shown similar results and have postulated that the neck region carries a higher complication rate secondary to shearing forces from the wide range of motion of the neck along with the thin tissue envelope in the skin of the neck. The most common complication is exposure followed by infection. Tissue expansion requires careful surgical planning, often multiple visits for serial expansion, and meticulous care of the site of expansion. Therefore, it is important that the family is well advised and is able to be compliant with the postimplantation care.

Tissue expansion is traditionally advocated for use with advancement flaps; however, in more difficult and larger areas of reconstruction, the use of an expanded transposition flap (Fig. 39.9) plays a powerful role in improving final contour, decreasing risk of anatomic distortion, improving scar position, and lowering the risk of contracture.

Drains are typically left in place until their output is less than 30 mL over 24 hours per drain. If skin grafts have been placed over periosteum or on cortical bone that has granulated, a bolster (or VAC sponge used as a bolster) is sewn in place for 5 to 7 days. Skin grafts that have been placed on muscle flaps are covered only with Adaptic and antibiotic cream. Bolsters are not used because of the possibility of compressing the circulation of the underlying flap.

The most common complication of the transposition of any regional flap will be loss of the distal tissue of the flap due to inadequate perfusion or venous congestion. To decrease this complication, regional flaps should be designed to incorporate at least one named artery in the base of the flap. A skin graft will not take if the recipient bed is not well vascularized. For exposed bone, if possible, fenestrate the outer cortex of bone to allow granulation tissue to cover the entire wound bed before applying a skin graft.

As a tissue expander progressively expands, the risk of extrusion is highest at the site used for implantation. Therefore, avoid placing incisions used for implant placement directly within atrophic scars or within skin graft sites. As an example, the patient in Figure 39.4 suffered one complication of implant extrusion when the incision for expander placement was placed just a few millimeters medial to the skin graft site in the left temporal area. The implant was removed after it became exposed. At a subsequent operation (1 month later), a second expander (Fig. 39.4F) was placed through an incision on the contralateral scalp. The site for this incision was chosen at the site where the back cut for flap transposition was anticipated. The scalp immediately adjacent to the skin graft was also not undermined so that the expander would not put pressure on this site as it expanded.

Scalp flaps can be associated with scar alopecia. The use of tissue expansion prior to the excision of lesion can reduce the risk of alopecia because the wound can be closed with less tension.

Defects of the lateral scalp and/or neck have a variety of etiologies. Whether the etiology is a malignant tumor, benign tumor, or trauma, the goals of reconstruction are to create an aesthetically acceptable, healed wound and to introduce the least amount of morbidity with the reconstruction. Skin graft reconstruction, regional flaps that may be tissue expanded, and free flaps are all methods of reconstruction with which the surgeon must be comfortable and have experience. Discussing the advantages and disadvantages of these approaches with the patient prior to extirpation is important so that the final reconstructive result is acceptable to the patient and that the patient’s postoperative expectations match the reconstructive outcomes.

• Anticipate the extent of the defect prior to tumor extirpation. If scalp or large areas of cervical skin are to be excised, question whether tissue expansion could serve a role in the reconstruction.

• If a CDP flap is to be used for reconstruction, any neck incision used for a neck dissection should be incorporated into the design of the flap.

• If a split-thickness skin graft is to be used, consider harvesting a skin graft from the scalp due to the better color match and the minimal morbidity. The donor site is first infiltrated with a tumescent solution (i.e., saline with 1:500,000 epinephrine). Scalp skin graft can be harvested with a thickness as thin as 0.005 to 0.007 inch.

• Regional scalp flaps should be designed to capture a named artery in the base of the flap.

• A tissue expanded flap can often provide greater versatility for reconstruction (i.e., greater movement) if harvested as a transposition flap (i.e., with back cuts along the expander capsule), instead of as an advancement flap.

• Pedicled flaps, in particular the scapular flap, can be converted to a free flap if the pedicle of the flap prevents adequate movement of the flap for reconstruction.

• A bulky musculocutaneous flap can be debulked by not including the overlying skin paddle and subcutaneous tissue. The pedicled muscle is then skin grafted.

• Skin grafts placed on cortical bone will not survive. This can be avoided by removing the outer layer of the cortical bone and allowing the area to granulate prior to placement of the skin graft.

• Expanders placed next to skin grafts are at risk for extrusion. Decrease the risk of this complication by choosing an incision for expander placement away from the skin graft site.

• Scalp flaps that are transposed into defects will leave a donor defect. Anticipate how the donor defect will be reconstructed (i.e., skin graft), and question whether the scalp flap can be designed so its transposition allows the donor defect to be placed in a less visible location on the scalp.

• Standard head and neck surgical set

• Dermatome

• Tissue expander equipment

SUGGESTED READING

Orticochea M. New three-flap scalp reconstruction technique. Br J Plast Surg 1971:24:184.

Lynch JR, Hansen JE, Chaffoo R, et al. The lower trapezius musculocutaneous flap revisited: versatile coverage for complicated wounds to the posterior cervical and occipital regions based on the deep branch of the transverse cervical artery. Plast Reconstr Surg 2002;109(2):444–450.

Deleyiannis FWB, Carolyn C, Lee E, et al. Reconstruction of the lateral mandibulectomy defect: management based on prognosis and the location and volume of the soft tissue resection. Laryngoscope 2006;116(11):2071–2080.

Deleyiannis FWB, Dunklebarger J, Russavage J, et al. Reconstruction of the marginal mandibulectomy defect: an update. Am J Otolaryngol 2007;28(6):363–366.

Rebelo M, Ferreira A, Barbosa R, et al. Deltopectoral flap: an old but contemporaneous solution for neck reconstruction. J Plast Reconstr Aesthet Surg 2009;62(1):137–138.