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

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