Mark K. Wax
INTRODUCTION
There are many options available in the reconstruction of scalp defects, each with its own indications, advantages, and disadvantages. The scalp can be challenging to reconstruct due to the inelasticity and thickness of the tissues. In comparison to the soft tissues of the rest of the head and neck, aging seems to make the tissue of the scalp less elastic and mobile. The ability to primarily reconstruct or entrain tissue from adjacent areas may not be easy. The primary goals of reconstruction of the scalp are to cover exposed bone (preventing desiccation and osteomyelitis), limit distortion of surrounding landmarks (eyebrows, ears, hairline), and provide an acceptable aesthetic outcome. To achieve optimal cosmetic results, significant attention should be paid to preservation of the normal hairline, directionality of hair growth, and well-disguised scars. For all malignant lesions, confirmation of negative margins should be obtained prior to definitive reconstruction and ease of continued surveillance for recurrent tumor should be considered. Reconstruction of the scalp requires a clear understanding of the anatomy and characteristics of the tissue. This will allow for proper preoperative planning and reconstruction.
Layers of the SCALP
The scalp consists of five layers, represented by the SCALP mnemonic. S, skin; C, subcutaneous tissue; A, galea aponeurosis; L, loose connective tissue; and P, pericranium (Fig. 37.1). The scalp is the thickest skin of the body. The skin and connective tissue are firmly adherent to the galea aponeurosis, which makes the skin inelastic. The subcutaneous layer contains the vasculature, nerves, and hair follicles. The galea aponeurosis is the strength layer of the scalp and consists of a thick, inelastic, fibrous sheet spanning between the frontalis muscle anteriorly, the occipitalis muscle posteriorly, and the temporoparietal fascia laterally. The loose connective tissue layer deep to the galea aponeurosis is an avascular plane that allows for mobility of the scalp and is the ideal plane of dissection for elevating flaps. The pericranium is the periosteum of the skull and is tightly adherent to the bone. This layer serves as a well-vascularized bed for skin grafts and can form granulation tissue if allowed to heal by second intention.
FIGURE 37.1 This schemata demonstrates the five layers of the scalp.
Mobility of the SCALP
The scalp is much less mobile than the soft tissue of the face. This makes primary closure and reconstruction with local flaps more difficult in comparison. The tissue laxity differs depending on the location in the scalp. The vertex is the least mobile, while the parietal regions have the greatest mobility. This is important to factor into the reconstructive plan as defects in the parietal region may be amenable to primary closure or local flap reconstruction, while the vertex may require skin grafting, tissue expansion for larger flaps, or free tissue expansion.
Vasculature of the SCALP
The vasculature of the scalp consists of five paired vessels from both the internal and external carotid arteries that form a rich anastomotic plexus centrally and are located in the deep subcutaneous layer just superficial to the galea aponeurosis. Anteriorly the scalp is perfused by paired supraorbital and supratrochlear arteries. These are the terminal branches of the internal carotid artery as it passes through the orbit. The supraorbital artery passes through the supraorbital notch, while the supratrochlear artery travels through the orbit and pierces the orbital septum in the same vertical plane as the medial edge of the eyebrow. The lateral scalp is perfused by two branches of the external carotid artery, the superficial temporal and postauricular arteries. The superficial temporal artery travels in a vertical direction within the temporoparietal fascia just anterior to the tragus and bifurcates into the frontal branch anteriorly and the parietal branch posteriorly. The posterior scalp is vascularized by paired occipital arteries. The occipital artery pierces the trapezius muscle just superior to the nuchal line and travels in the deep subcutaneous layer until it forms anastomoses with surrounding vessels. The venous drainage of the scalp corresponds to the named arterial vessels and subsequently drains into the common facial, external jugular and internal jugular veins. Understanding the location of these vessels is imperative when designing local and regional flaps as they should be pedicled off one or two vessels to ensure an adequate blood supply to perfuse the distal aspect of the flap.
Nerves of the SCALP
There are eight nerves that supply sensation to the scalp, four anterior to the auricle and four posterior. The nerves supplying sensation to the anterior scalp originate from the trigeminal nerve and include the supraorbital (V1) and supratrochlear nerves (V1) and zygomaticotemporal (V2) and auriculotemporal (V3) nerves. The supraorbital nerve travels with the supraorbital artery through the supraorbital foramen and divides into the superficial and deep branches. The supratrochlear nerve passes above the trochlea and exits the orbit medial to the supraorbital notch. The nerve then pierces the corrugator muscle and the frontalis muscle and travels to supply sensation to the central forehead and medial upper eyelid.
The zygomaticotemporal nerve exits the facial skeleton at the zygomaticotemporal foramen, travels through the temporalis muscle, and pierces the temporalis fascia above the zygomatic arch to innervate the skin of the temple. The auriculotemporal nerve travels through the parenchyma of the superficial parotid gland and exits posteriorly over the zygomatic arch. The nerve then travels superiorly in the temporoparietal fascia to innervate the tragus, anterior portion of the ear, and the posterior temple. The four nerves supplying sensation posterior to the auricle include branches of the cervical plexus, which includes the great auricular (C2 and C3), greater occipital (C2 and C3), lesser occipital (C2), and third occipital (C3). These nerves have been found to communicate freely with one another.
HISTORY
When determining the appropriate method of reconstruction, there are multiple questions that must be asked. A thorough history must be obtained to determine the patient’s desires in regards to aesthetic outcomes. It is important to get a full past medical history with specific attention to comorbidities that may delay wound healing, such as diabetes mellitus, chronic immunosuppression, smoking, or the risk of postoperative bleeding from taking anticoagulants, aspirin, or herbal supplements.
An important factor to consider is whether there has been any previous surgery or radiation to the scalp. Many patients will have been previously treated. Either surgery or radiation will affect the ability to use local tissues in the reconstruction. If the defect is a result of the excision of a malignant lesion, the type of cancer, confirmation of negative margins, and risk for recurrence are important to determine prior to reconstruction.
PHYSICAL EXAMINATION
A thorough examination of the head and neck should be performed with a detailed evaluation of the primary defect and surrounding tissue. When evaluating the primary defect, it is necessary to note the characteristics of the defect itself as well as the surrounding tissues. Determining the size and location of the defect and the mobility of surrounding tissue will help to determine if the defect is amenable to primary closure or reconstruction with a local flap. The quality, thickness, presence of hair, and the location of nearby landmarks will dictate what local flap design options are available. The exposure of bone or dura is important to note, and these defects should be reconstructed appropriately to avoid desiccation and infection. A thorough assessment and documentation of facial nerve function is important to note as is sensation to the surrounding tissues. If the defect is secondary to malignancy, the scalp and face should be evaluated for other suspicious lesions, and the parotid glands and neck should be palpated to identify possible metastatic lymph nodes.
INDICATIONS
The indications for reconstruction of the scalp include any defect that cannot be closed primarily. An algorithm is detailed below.
CONTRAINDICATIONS
There are no absolute contraindications to reconstruction of a scalp defect, as all scalp defects should be repaired. An open conversation should be held with the patient and his or her family discussing the goals of the procedure, expected functional and aesthetic outcomes, and risks associated with the procedure.
PREOPERATIVE PLANNING
Methods of reconstruction include many options including healing by secondary intention, skin grafts, primary closure, local tissue flaps, regional tissue flaps, and free tissue transfer. There are limitations and advantages to each technique, and careful consideration is needed to determine the ideal method for reconstruction, based on the size and location of the defect and the patient’s desires and ability to tolerate extensive surgery. In general, the simplest technique that gives the desired functional and cosmetic outcomes should be chosen.
SURGICAL TECHNIQUE
Second Intention
With this method, the wound is covered with a nonadherent dressing and allowed to slowly granulate. It is important to have vascularized tissue upon which granulation tissue will grow. Ideally, bone is covered with a minimum of pericranium. If bone is exposed and lacking pericranium coverage, then the outer cortex of the skull can be drilled down to the diploic space that will provide a vascular bed for granulation tissue to form. A second option is to cover the exposed bone with a pericranial or temporoparietal tissue flap, based on a vascular pedicle. The primary advantage of this technique is the quickness of the procedure. Disadvantages of secondary intention are the prolonged period of time while the wound is granulating. With large defects, it can take months of local wound care until the area is healed. Frequent use of ancillary personal is required to assist in the care of the wound. Alopecia of the healed wound and relative thin skin make the area susceptible to trauma. Frequent wound breakdown is common and bothersome to the patient. The area must be protected from any trauma.
Split-/Full-Thickness Skin Grafts
Split-thickness and full-thickness skin grafts are options for closing a wide range of scalp defects. These grafts must be placed onto a bed of well-vascularized tissue, which includes periosteum, granulation tissue after delay in closure, mobilized pericranial or musculofascial flaps, or after drilling off the outer cortex of the skull. It is important to remember that this is not an acceptable reconstructive option if radiation therapy has been given or is planned postoperatively. The negative aspects of skin grafts include alopecia, insensate skin, risk for ulceration or breakdown with mild trauma, poor color match, and often a depressed and an undesirable aesthetic outcome (Fig. 37.2).
FIGURE 37.2 This patient had a large area of the scalp resected with reconstruction with a split-thickness skin graft. The graft has healed well and can be seen to be quite thin. The areas of redness are local areas that have broken down due to trauma. These will heal, but inevitably other areas will break down.
Primary Closure
These defects are typically transformed to an elliptical shape with the long axis perpendicular to the plane of maximum laxity, and wide undermining is required in the subgaleal plane. Typically, this option is used for defects less than 4 cm in diameter. If the defect is near the anterior hairline, an M-plasty may be performed to prevent exposed incisions into the non–hair-bearing areas. When possible, this method is simple and typically gives the best cosmetic outcome with similar tissue and proper directionality of hair follicles. This method should not be used if significant tension must be applied to close the wound.
Local Flaps
Local tissue transfer from surrounding skin is a major method of scalp reconstruction for small to mediumsized defects. This technique can offer both excellent function and aesthetic outcomes when primary closure is not possible. This follows the principle of “replace tissue with like tissue.” Tissue flaps should be properly designed to minimize tension on the wound closure, maintain blood flow, and create ideal aesthetic outcomes. Local flaps can be used to reconstruct defects measuring up to approximately 50 cm2. When local flaps are used together with split-thickness skin grafts, it has been reported that large defects up to 150 cm2 can be reliably closed. The skin grafted defects are then reconstructed with secondary procedures after the wound has healed. When reconstructing larger defects, it is important to create a tissue flap with a wide base that is dependent on one or more major arteries. The handheld Doppler probe can help to identify the course of the vascular pedicles of these flaps.
Advancement Flaps
Advancement flaps are mobilized by sliding the elevated flap in one direction toward the primary defect. This is done best with areas of redundant skin or increased elasticity. The surrounding tissue is undermined in order to close the defect and decrease tension on the wound closure. The subgaleal loose connective tissue plane on the scalp allows for easy, avascular undermining. The site of greatest tension is the distal edge of the skin flap. There are multiple types of advancement flaps: Unipedicle, bipedicle, V to Y, Y to V, and island. This method of closure is ideal for reconstruction of small scalp defects in patients with mobile scalp tissue. For large scalp defects, advancement flaps are suboptimal due to the lack of elasticity of the scalp.
Pivotal Flaps
Pivotal flaps are the most frequently used type of scalp reconstruction. These are moved toward the primary defect by pivoting around a fixed point at the base of the skin pedicle. There are multiple types of pivotal flaps for the scalp: Rotation, transposition, and interpolated flaps. It is better to close a moderately sized scalp defect with multiple rotation flaps (2 to 3) rather than just one. Multiple flaps decrease the size of each individual flap, as they will all share in providing tissue to cover the defect. Closure of the secondary defects may be easier as they will not be as large if multiple flaps are used. With all pivotal flaps, a standing cutaneous deformity will be present at the base of the skin pedicle after it is rotated into place. Caution should be used when deciding to excise the standing cutaneous deformities to keep from narrowing the base and compromising the blood supply. Often the standing cutaneous deformity can be left in place as it will flatten out with time and offer an acceptable cosmetic appearance without further excision (Fig. 37.3A–C). The flap is usually elevated in a subgaleal plane. Once enough scalp has been elevated to allow for closure, the wound is closed in two layers. I use a 3-0 suture that lasts 1 to 2 months for the deep layer and a fast-absorbing suture for the skin. Drains are not needed as the scalp lies on the bone of the skull and collections of fluid are rare.
FIGURE 37.3 A small defect in the apex of the scalp is present. A. The proposed flap and the excision are marked out. B. A rotation advancement flap is used to close the defect. C. The final outcome is a linear scar. The patient has also had a large defect from excision of a tumor reconstructed with a free flap anterior to the current lesion.
Rotation Flaps
Rotation flaps have a curvilinear configuration and are designed so that the flap is placed immediately adjacent to the defect. Often the primary defect is modified to a triangular shape to aid with inset of the flap. The proposed length of the rotation flap should be four times the width of the primary defect (4:1). This is great for closure of scalp defects given the convex shape of the skull and the inelastic nature of the galea aponeurosis.
Examples include the O–T flap. This is a local flap commonly used for closure of scalp defects due to the simple design and reliability. This technique entails bilateral curvilinear rotation flaps rotated around individual pivot points. Using more than one rotational flap allows for a decrease in the length of the incision as tissue laxity is recruited from opposite sides of the defect. The primary defect is modified to a circular defect. In the O–T configuration, the flaps are rotated in opposite directions, and the final incisions resemble a “T” (Fig. 37.4A–C). The O–Z configuration is designed for rotation in the same direction so that the final closure resembles a “Z.” This is also referred to a “yin yang” flap due to the appearance of the initial flap design. The flap is usually elevated in a subgaleal plane. The wound is closed in two layers in all of these flaps once enough scalp has been elevated to allow for closure. I use a 3-0 suture that lasts 1 to 2 months for the deep layer and a fast-absorbing suture for the skin. Drains are not needed as the scalp lies on the bone of the skull and collections of fluid are rare.
FIGURE 37.4 A. The defect here is circular and is to be closed with two curvilinear advancement/ rotation flaps. B. The flaps have been elevated and rotated to meet in the middle of the defect. C. The end result is a curvilinear scar that is straight in the middle.
Algorithm for Surgical Management
Defects of the Anterior Scalp:
• Careful attention should be given to reconstruction of the anterior scalp to minimize distortion of the hairline.
• Defects involving both the scalp and forehead should be reconstructed as two separate defects to maintain the hairline.
• For bald patients, incisions should be oriented parallel to, and when possible, within existing rhytides.
• When designing rotational flaps, orient secondary dog-ears toward the parietal and occipital scalp regions where they will be less obvious.
Options for Managing Small Defects (<2 cm2)
• Primary closure
Options for Managing Moderate-Sized Defects (2 to 25 cm2)
• Local flaps
• Along hairline: advancement flap or rotation flap
• Hair-bearing scalp: O to Z flap
Options for Managing Large-Sized Defects (>25 cm2)
• Temporoparietal occipital flap to recreate anterior hairline
• Non–hair-bearing scalp: large rotation advancement flap based on occipital artery ± skin grafting to close donor site.
Options for Managing Extreme-Sized Defects (>50 cm2)
• Orticochea flap
• Free flap
Defects of the Parietal Scalp
Defects in this region are the easiest to close primarily due to the mobility of the scalp in this region.
Options for Managing Small-Sized Defects (<2 cm2)
• Primary closure
Moderate-Sized Defects (2 to 25 cm2)
• Local flaps
• Rotation or advancement flaps (All dog-ears should be positioned posteriorly where they are less noticeable)
Options for Managing Large-Sized Defects (>25 cm2)
• Orticochea flaps may be difficult to design in this region to allow adequate coverage. Consider skin grafts with secondary reconstruction and tissue expansion.
Options for Managing Extreme-Sized Defects (>50 cm2)
• Free flap
Defects of the Occipital Scalp:
Defects in this region of the scalp are less noticeable and can be easily camouflaged with longer hair.
Options for Managing Small-Sized Defects (<2 cm2)
• Primary closure
Options for Managing Moderate-Sized Defects (2 to 25 cm2)
• Local flaps
• Rotational flaps/advancement flaps
• Dissection and undermining can be carried over the trapezius and splenius capitis muscles to allow for increased tissue mobility.
Options for Managing Large-Sized Defects (>25 cm2)
• Orticochea flap
• Regional flaps: trapezius myocutaneous or pedicled latissimus dorsi myocutaneous flap
Options for Managing Extreme-Sized Defects (>50 cm2)
• Orticochea flap
• Microvascular free flap
Defects of the Vertex:
There is limited mobility of the vertex of the scalp and primary closure may not be possible for even small defects. Wide undermining and galeatomies are often needed to recruit sufficient skin laxity from surrounding tissue.
Options for Managing Small-Sized Defects (<2 cm2)
• Primary closure
• Pinwheel rotational flaps
• This can recreate the natural spiral hair growth pattern that occurs at the vertex
Options for Managing Moderate-Sized Defects (2–25 cm2)
• Local flaps
• O to Z rotational flaps
Options for Managing Large-Sized Defects (>25 cm2)
• Large rotation advancement flap based on occipital artery ± skin grafting to close donor site.
Options for Managing Extreme-Sized Defects (>50 cm2)
• Free flap
POSTOPERATIVE MANAGEMENT
The primary goal of postoperative care is to promote proper healing and survival of the flap or skin graft. Common complications include hematoma, infection, wound dehiscence, loss of flap or graft, poor flap design, and unwanted scarring. Prevention of postoperative bleeding and hematoma begins in the operating room with adequate hemostasis. Hematomas are most common in the first 48 hours after surgery. In scalp reconstruction, these are very rare.
All skin grafts should have a secure pressure dressing to prevent shearing or hematoma formation under the graft, which will lead to necrosis. To prevent infection, adherence to sterile technique during the procedure is imperative.
Excess tension on skin incisions should be avoided to prevent wound dehiscence and excess scarring. Careful wound monitoring by the patient or family is important, and any change in appearance or delayed healing should be reported to the surgeon. The patient and family should be educated regarding the expected healing process, proper wound care, and potential complications.
COMPLICATIONS
Complications range from wound breakdown to flap tissue necrosis. Complications are generally rare and most can be managed with debridement and local wound care.
RESULTS
The results with each of the techniques reviewed herein are generally excellent. I find that each of the techniques requires a proficiency that is gained through experience, but the results in most patients are excellent.
PEARLS
• The reconstructive method should be tailored to the patient’s needs.
• Adequate injection of local anesthesia with epinephrine should be used to help to provide hemostasis and may assist with hydrodissection.
• Dissection is to be performed in the subgaleal layer. Avoid trauma to hair follicles in the subcutaneous layer.
• Large flaps should be based on one to two arterial perforators to ensure adequate perfusion.
• Scalp incisions should be closed in two layers.
PITFALLS
• Alopecia and scarring may result from excess tension on the wound closure.
• Mechanical creep and galeatomies will help to decrease wound closure tension.
• Avoid excision of dog-ears until after scalp has healed. When possible, place dog-ears on the posterior aspect of the scalp where they are less noticeable
INSTRUMENTS TO HAVE AVAILABLE:
• Head and neck surgical tray
• Hemostatic scalp clips
SUGGESTED READING
Orticochea M. New three-flap reconstruction technique. Br J Plast Surg 1971;24(2):184–188.
Vecchione TR, Griffith L. Closure of scalp defects by using multiple flaps in a pinwheel design. Plast Reconstr Surg 1978;62(1):74–77.
Frodel JL Jr, Ahlstrom K. Reconstruction of complex scalp defects: the “Banana Peel” revisited. Arch Facial Plast Surg 2004;6(1):54–60.
Kruse-Lösler B, Presser D, Meyer U, et al. Reconstruction of large defects on the scalp and forehead as an interdisciplinary challenge: experience in the management of 39 cases. Eur J Surg Oncol 2006;32(9):1006–1014.
Mehrara BJ, Disa JJ, Pusic A. Scalp reconstruction. J Surg Oncol 2006;94(6):504–508.