Background
In approaching the reconstruction of the forehead and the temple, the following goals should be emphasized:
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Preservation of the motor function of the frontal branch of the facial nerve because injury to the nerve can result in eyebrow ptosis
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Maximal preservation of the sensory nerves, when possible, because injury to the supratrochlear nerve or the supraorbital nerve can lead to permanent anesthesia of the forehead
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Careful reconstruction of the cosmetic units of the forehead and the temple to maintain the position and the symmetry of the eyebrows and the frontal and temporal hairlines
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Camouflage of the surgical scars by placing them in relaxed skin tension lines or by placing them adjacent to the hairline or the brow. [1]
Presentation
A complete history and physical examination must be performed prior to any surgical procedure. Patients with cardiac disease or immunosuppression may require medical clearance by an internist prior to surgery.
Indications
Indications for forehead and temple reconstruction include trauma and removal of benign and malignant tumors.
Relevant Anatomy
The forehead unit is defined superiorly by the junction lines of the frontal portion of the scalp, laterally by the temporal region of the scalp and the temple, and inferiorly by the eyebrows and the glabella. A thin layer of subcutaneous fatty tissue covers the 2 joined bellies of the frontalis muscle, which is the principal muscle of the forehead. The skeletal muscle fibers course vertically, leading to the transverse orientation of the relaxed skin tension lines. A layer of thin supramuscular fascia covers the frontalis muscle.
The inframuscular component of the frontalis muscle fascia is an inelastic adherent sheath, which can limit the mobility of the skin-muscle-fascia complex. [1] In the median part of the forehead, the galeal median raphe extends anteriorly, limiting tissue mobility. Injury to the frontalis muscle can lead to local palsies with prolonged recovery time. [2]
The right and left supratrochlear and supraorbital arteries and the branches of the internal carotid arteries provide the vascular supply to the central aspect of the forehead. Laterally, the frontal branches of the superficial temporal artery, which anastomose with the internal carotid arteries, supply the forehead.
The temporalis branch of the facial nerve innervates the frontalis muscle. This nerve is susceptible to injury over the zygomatic arch, in which the subcutaneous tissue is thin. The temporalis nerve innervates the frontalis muscle from its undersurface within the inframuscular fibrous fascial component. Injury to this nerve can lead to eyebrow ptosis. The sensory nerves of the forehead are the supratrochlear nerve and the supraorbital nerve that course with their namesake arteries. Injury to these nerves usually occurs as a result of deep transverse incisions into the frontalis muscle, and it may result in temporary or permanent anesthesia from the point of the incision to the midpoint of the crown. [1]
Contraindications
Surgery is contraindicated in patients (eg, those with a history of coronary artery disease) who do not have medical clearance by their internist. In addition, extreme caution must be used in patients with known allergic reactions to anesthetics.
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The forehead can be divided into 3 subunits: the midline (M), the paramedian (P), and the lateral (L) areas. T = Temple.
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Midline forehead defect closed by primary vertical closure and inferior M-plasty.
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Defect on the paramedian aspect of the forehead repaired with horizontal closure.
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Defect on the paramedian aspect of the forehead repaired with vertical closure.
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Defect on the paramedian aspect of the forehead repaired by a bilateral advancement flap.
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Large defect on the paramedian part of the forehead repaired by a full-thickness skin graft.
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Defect on the temple repaired by horizontal primary closure with medial M-plasty.