CHAPTER
54

If wound closure is the primary goal, following the sequential steps of the ‘‘wound closure’’ ladder is appropriate (e.g., secondary intention, primary closure, skin graft, locoregional flap, free flap). If the main goal is to reconstruct the defect or deformity, especially in aesthetic reconstruction, the process should not be sequential; instead the best option should be used, even if a more straightforward procedure would work to close the wound.1

The next consideration is determining the limitations that may preclude obtaining the initial goals and ensuring that the patient, family, and surgeon have realistic expectations.

Etiology and Analysis of Defects

The magnitude and complexity of a scalp defect depends upon a variety of causative factors. They may be full-thickness or partial-thickness in depth and can be classified as congenital or acquired. Congenital defects may include² cutis aplasia or defects arising from other congenital lesions (congenital nevi, congenital vascular malformations, and congenital tumors). Acquired scalp defects have several possible causes:

• Injuries, such as burns

• Blunt or penetrating trauma

• Avulsion injuries leading to ‘‘degloving’’ of the scalp

• Tumor invasion

• Infection

• Oncologic resection

• Radiation

• Wound-healing difficulties

Preoperative anticipation of potential difficulty with direct closure when the scalp has been compromised by one of these circumstances or conditions is crucial to success. The initial evaluation of the defect is based on its size and location, tissue involved, and structures exposed, such as pericranium, cranium, devascularized bone flaps, prosthetic material, dura, brain parenchyma, or vessels. In addition, the quality of the surrounding tissue (scarring, infection, radiation) and aesthetic concerns such as contour, skin color match, hairline, brow position, and subunits (e.g., forehead) must be considered.³

After assessing the size and location of the defect (or anticipated defect), the structures involved, the surrounding tissue quality, and the patient’s comorbidities, the next step in preoperative planning is to define the operative goal. Is the goal to close the wound or reconstruct the defect? Sometimes these two goals are in sync.

If aesthetic reconstruction is the goal, then multiple staged procedures may be needed to obtain the best result. Frequently, wounds are initially closed in the most straightforward way, with the anticipation that secondary reconstruction with tissue expansion or other reconstructive technique will be performed secondarily.

In the case of terminal disease, one may adjust the reconstructive approach depending on whether the goal is control or palliation. If tissue quality is poor due to scarring, radiation, or infection and if local options are unavailable or unreliable, then distant tissue is indicated. Sometimes, even if local, less complicated options are technically feasible, they are more likely to have an unfavorable result, because distant tissue is safer and more reliable in ensuring uncomplicated healing.^4–6 This approach is especially important if there is exposure of vital structures.

Patient Selection

It is critical for the surgeon to not only determine the etiology of the defect, but also to identify patients at high risk who therefore have a higher chance of a detrimental outcome. In this regard, it has been our overwhelming experience that previous radiation, previous or concurrent infection, exposed hardware, concurrent cerebrospinal fluid (CSF) leak, previous multiple cranioplasties, and cigarette smoking are deterrents to successful reconstruction of the complex scalp defect.7 In these cases, the complication rate has been noted to escalate to 59% in one study.⁸ To help guide reconstructive choices in these difficult scenarios and minimize major complications as well as unfavorable results, we have developed a severity scoring system: The University of Chicago CRAnial Severity Score of Hostility (CRASSH)⁹ (Table 54.1), which serves as a tool for decision-making in the reconstruction of composite scalp–cranial defects.

Table 54.1 University of Chicago CRAnial Score of Severity of Hostility (CRASSH)

Classically, the reconstructive surgeon can resort to primary closure with undermining of isolated scalp defects if the defect is less than 3 cm in diameter, especially if the defect is posteriorly located10 (Fig. 54.1). Frequently, post-traumatic wounds have the appearance of tissue loss but, on careful inspection, are found to not be missing any tissue. These wounds can usually be closed directly if minimal tissue needs to be débrided. Limitations of that approach may exist based on the surrounding tissue quality or exposure of vital structures. Maneuvers that facilitate closure, such as local advancement flaps, undermining the tissue, and scoring of the galea¹¹ helps in reducing tension and increases the chances of stable wound coverage. However, the surgeon must be careful to not score too deeply or close under too much tension, both of which will compromise the blood supply and lead to marginal necrosis, wound breakdown, or alopecia.

Secondary Intention

Dr. Frederic Mohs’ initial approach¹² of healing small forehead and scalp defects with secondary intention by granulation, contraction, and reepithelialization, can be used and is often applied in the case of paramedian forehead flap donor sites. In the congenital case of cutis aplasia, simple defects can be allowed to close by secondary intention with the application of a topical antimicrobial, and no surgical intervention is needed.¹³ Although healing by secondary intention frequently leads to acceptable results in patients of Western European descent (Fig. 54.2), patients with darker skin frequently heal with more noticeable hypopigmented or hyperpigmented scars. In the scalp area, the healed defect will be alopecic but will have also reduced in size significantly because of the contraction component of secondary healing.¹⁴

Fig. 54.1 Primary closure. Posterior scalp wound (a) facilitated by loose skin from the neck (b).

Fig. 54.2 Healing by secondary intention. (a) A patient with an open scalp wound referred for closure. (b) One month after treatment with a topical antimicrobial. (c) After 3 months.

Patients who are bald and have defects in these non–hair-bearing areas are often best served with a skin graft, whereas defects within the hair-bearing portion are typically aesthetically unacceptable. Color differences can be minimized by harvesting from the scalp. Using hair-bearing scalp has the added advantage of hiding the donor site under hair (when it grows back) (Fig. 54.3). Split-thickness skin grafts typically do not tolerate radiation very well, especially if a significant amount of desquamation occurs from the radiation.³ If adjunctive radiation is anticipated, the surgeon should consider using a fasciocutaneous flap instead; if it desquamates, it has the capacity to reepithelialize.

Robinson (1908)¹⁵ was the first to describe that a skin graft can take directly on pericranium rather than waiting for the wound to be covered by granulation tissue first. Another method to be considered when the outer table of the cranium is exposed is to drill burr holes into the diploe, await granulation tissue to cover the bone, then skin graft the granulation tissue. Alternatively, the outer table of the skull can be removed or burred down and a skin graft can be placed directly on the well-vascularized diploe.¹⁶ Without the gliding capacity of the pericranium, however, these grafts are often prone to minor wound breakdown. This is also the case in wounds devoid of pericranium that are covered initially with a bilayer wound matrix or acellular dermal matrix, which has gained popularity for scalp wounds of this nature^17,18 (Fig. 54.4).

Tissue expansion is certainly an ideal reconstructive option of choice for hair-bearing scalp defects, because no other technique can provide ‘‘like tissue’’ for large defects.^19,20 Temporary skin grafting with the anticipation of subsequent removal after tissue expansion of adjacent local tissue from the same aesthetic unit provides a superior cosmetic outcome (Fig. 54.5). The main disadvantages of tissue expansion are the need for multiple procedures, the temporary aesthetic deformity of having expanders, and the lengthy treatment period of several months during expansion, necessitating optimal compliance from the patient and/or caregivers.^19,21 The major complications associated with tissue expansion are wound breakdown, extrusion, and infection. Wound breakdown and extrusion can be minimized by placing the incisions perpendicular rather than parallel to the direction of expansion (see Fig. 54.5d), avoiding folds in the expander and avoiding having any incisions overlying the expander, its tubing, and port.¹⁹ Another consequence of tissue expansion is the molding or erosion of the skull from the pressure of the expander (see Fig. 54.5i). Although this can potentially lead to disastrous consequences,²² bony contour irregularities caused by tissue expansion generally spontaneously improve with time. To minimize unfavorable results, not only do the previously mentioned issues need to be considered, but the plan of how the expanded flaps will be moved needs to be determined at the time of insertion. Axial transposition flaps will more likely accomplish the goal rather than direct advancement flaps. In addition, because whether expanded flaps will totally cover the defect to be resurfaced cannot be easily predicted, it is prudent to only excise the lesion or scar after ensuring the expanded flap will indeed cover the defect. Otherwise, the surgeon might be tempted to “push” the limits of the flap and compromise its circulation, or areas that cannot be resurfaced with the expanded flap may need repeat grafting.

Fig. 54.3 (a) Melanoma of the left anterior scalp. (b) Wide excision. (c) Wound temporized with bilayer wound matrix. (d) Split-thickness skin graft harvested from hair-bearing scalp. (e) Aesthetic deformity of the recipient site and hidden donor site 1 year later. (f) The patient uses a “comb-over” technique in an attempt to hide the aesthetic deformity.

Fig. 54.4 (a) Wide excision of skin cancer with removal of outer table of calvarium. (b) After placement of bilayer wound matrix. (c) Fourteen months after split-thickness skin graft. (d) Minor trauma to adherent skin graft 3 years after placement. Atrophic changes occurred over time.

Fig. 54.5 (a) A burn injury to the scalp of a 2-year-old patient. (b) After tangential excision of burn eschar. (c) The wound was closed with a split-thickness skin graft with significant burn alopecia. (d) Incisions for the expander placement, placed perpendicular to the expander. (e) Hair-bearing scalp was expanded for 4 months. (f) The anterior hairline was marked using a template from the contralateral side. (g) A left transposition flap was incised and the expander removed. (h) The area was “resurface-tested” before excision of the alopecic area. (i) Bone molding was noted under the expander. (j) After resurfacing of the entire alopecic area with expanded hair-bearing flaps.

When considering local flap reconstruction of the head and neck, the surgeon must think in two broad categories: aesthetic subunit reconstruction or nonsubunit reconstruction. There are no separate aesthetic units of the scalp, but there is a clear distinction between the hair-bearing scalp and the aesthetic unit of the forehead. When using scalp flaps, the surgeon must be cognizant of the hairline and avoid distortion of the brow. In addition, the reconstructive surgeon must respect the direction of hair growth. A swatch of hair growing in the wrong direction can negatively affect an otherwise excellent reconstruction. The thick, inelastic nature of the scalp can make local tissue rearrangements (with direct closure of the donor site) difficult. Closure under tension often leads to loss of hair in a widened scar, marginal necrosis, and wound breakdown, which is devastating when underlying hardware is used. To avoid this, when large local flaps are performed, the donor sites frequently need to be skin grafted to minimize tension (Fig. 54.6). Rotation, transposition, or geometric flaps can provide acceptable cosmetic results if the defect is small to moderate size.^23,24

Multiple locoregional flaps have been described.^25,26 For example, Raposio et al²⁷ described the use of three adjacent rhomboid flaps in the vertex area to reconstruct the natural whorl pattern of the hair in that region. A combination of rotation and advancement is often used to cover larger defects requiring a long curvilinear incision, which incorporates at least one of the named scalp vessels, allowing for maximal excursion while maintaining vascularity.

In geometric terms, the length of the rotation flap should exceed five times the diameter of the defect to get adequate tension-free closure²⁸ (Fig. 54.7). Galeal scoring, back-cutting, and undermining of the scalp in the subgaleal plane can help minimize tension as well. The results of these flaps appear better in hirsute scalps than bald heads, which do not have hair or skin lines to hide the scars (Fig. 54.8).

Fig. 54.6 Local transposition flaps that could not be closed primarily because of tension; a skin graft was placed to close the wound without tension.

Fig. 54.7 (a) A soft tissue tumor just behind the hairline. (b) After excision. (c) Closure with a large rotation flap to avoid distortion of the hairline or brow. (d) Final result 3 weeks postoperatively.

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