Forehead Flap

Frederick J. Menick

INTRODUCTION

Although some patients may be satisfied with a healed wound, most wish to have their normal appearance and function restored. Traditionally, the emphasis has been on measuring the length, width, and depth of the defect, but the wound may not reflect the actual tissue loss. A fresh wound is enlarged by edema, local anesthesia, gravity, and tension. A wound, which heals by secondary intention, contracts as the defect tissue heals. A defect within an area of a previous reconstruction is often distorted by scar, mismatched quality and dimension of previous grafts and flaps, and the malposition of adjacent residual landmarks. Injury to a three-dimensional landmark presents as a two-dimensional defect. Equally important, clinical experience and skill are finite, while the variety of defects is infinite. Fortunately, the normal never changes and can be employed as a visual guide to formulate principles and a plan. The normal is described by topographic subunits of characteristic skin quality, border outline, and three-dimensional contour.

Although Gillies’ principle of “like” tissue is useful, a flat thick forehead, septal, ear or rib cartilage, and most lining materials are very dissimilar to nasal tissues. Only, the quality of the forehead skin actually matches what is missing. So, the surgical plan must acknowledge the need to modify “quasi-like” donor tissues to suit the needs of each anatomic layer and the overall requirements of form and function. Tissues must be modified in thickness, outline, and contour to restore the quality, border outline, and three-dimensional contour and function of the nose. Recreating the complex three-dimensional contour of tip and ala—the most aesthetically important parts of the nose—is a special challenge.

Success requires the replacement of thin, conforming cover, which matches nasal skin in color and texture; thin, vascular, and supple lining, which does not occlude the airway; and a three-dimensional hard tissue framework to support, shape, and brace the soft tissues against gravity, tension, and scar contraction. Ideally, the materials and methods available for repair are applicable to varied defects; provide available and well-vascularized donor tissues; are reliable, safe, and predictable; permit intraoperative modification of donor tissues; and provide an opportunity to revise inevitable imperfections or to salvage a complication.

HISTORY

This college student was knocked off his scooter by an automobile (Fig. 42.1A-C). He suffered a fracture of his thoracic spine, grade 1 laceration of the spleen, an injury to the brachial plexus, and a nasal fracture with amputation of tip skin, the right alar cartilage, and full-thickness loss of the right ala and sidewall.

A laminectomy and repair of the brachial plexus were performed. The amputated nose was retrieved and sutured back in place. The 6-cm² composite graft failed completely (as most traumatic amputations do). A few weeks later, nasal reconstruction was attempted with a two-stage forehead flap. Cartilage grafting had been recommended to improve the final result.

FIGURE 42.1 Tip skin, the underlying right alar cartilage, skin of the inferior dorsum and sidewall, and the full-thickness of the right ala were traumatically amputated. After repair with a two-stage forehead flap, the forehead is scarred (A, B), and the nose remains distorted (C).

PHYSICAL EXAMINATION

Fourteen months after injury, the nose is significantly distorted and obstructed. The forehead flap, although matching in skin quality, appears as a shapeless patch, surrounded by scars. The right alar rim is retracted, and the nasal vestibule is stenotic. A shiny atrophic scar is present under the right hairline in an area of secondary healing. The right oblique forehead flap’s pedicle, at least 2½ cm wide, had been replaced within the inferior forehead unit, creating additional scars. The right brow is malpositioned inferiorly.

INDICATIONS

All complex nasal reconstructions will require a revision after pedicle division. The surgeon must evaluate the initial result in dimension, volume, position, projection, symmetry, landmarks, and nostril size. If basic nasal form is correct, modest abnormalities—poorly defined landmarks, a thick rim, or a stenotic nostril—can be improved during a revision. The flap can be reelevated through its peripheral borders, or direct incisions can be made on its surface (disregarding old scars) to reestablish landmarks. Excess soft tissue is sculpted and additional secondary cartilage grafts placed to address the limitations of the initial repair. However, when cover and lining are grossly deficient, the repair must be totally redone with a second regional flap. The normal must be returned to its normal position, the defect recreated, and tissue deficiencies defined and replaced. Occasionally, excess tissue, which would otherwise be discarded, can be used as hingeover lining flaps, for bulk replacement to an area of soft tissue deficiency or other purpose.

Large, deep nasal defects—those greater than 1.5 cm in diameter or requiring cartilage replacement, full-thickness defects, or those adversely located in the infratip or columella where local flaps do not reach, must be repaired with regional flaps. Local flaps will be inadequate.

A two-stage nasolabial flap is best suited for superficial defects of the ala, resurfaced as a complete sub-unit. A nasolabial flap is precluded, in this case, by the size and depth of the defect, inadequate reach, borderline
vascularity, and the risk of severe pincushioning. A nasolabial flap would also add unnecessary scarring and distortion to the central face of this young man with an indistinct nasolabial fold and little excess tissue. A second forehead flap is the only choice because of its reliability, effectiveness, efficiency, and wide application.

PREOPERATIVE PLANNING

Taking the time to evaluate the deformity and develop a thoughtful reconstructive plan is vital.

Although the exposure of vital structures may motivate early coverage, a careful evaluation of the patient’s overall health and goals and the status of the wound must be performed preoperatively.

A preliminary operation to debride unhealthy tissue, control infection, recreate the defect and return the flap to its normal position, or restore a stable platform by initially repairing the cheek and nasal lip base may be necessary. In this case, the tissues were well healed and the nasal lip and cheek platform was stable. The defect could be recreated and formal nasal repair performed simultaneously.

SURGICAL TECHNIQUE

Operative decisions are guided by principles of aesthetic regional unit reconstruction:

Alter the wound in size, outline, depth, or position, if helpful, to improve the final result.

This may include discarding adjacent residual skin within a subunit (enlarging the wound), the advancement of adjacent skin to the border of a subunit (decreasing the size or outline of the defect), or a combination.

Missing tissues must be replaced in exact dimension and outline. Inaccurate tissue replacement malpositions normal landmarks by pushing or pulling residual tissues outward or inward.

Because the wound does not reflect the true tissue loss, the contralateral normal or ideal are used as a guide to determine the correct dimension and outline of all replacement tissues—cover and lining flaps and cartilage grafts. Operative templates are used to design exact grafts and flaps and to determine the ideal position of important landmarks—such as the alar base inset and alar crease.

Stage 1: Flap Transfer

A three-stage full-thickness forehead flap to resurface the nose and septal and ear cartilage grafts for support was planned. The lining deficit would be replaced with an extension of the forehead flap or by hinging over the previous forehead flap for lining.

The hairline, frown lines, and subunits of the nose and lip were marked with ink to identify the outline of the subunits, old scars, the old flap and important landmarks (Fig. 42.2A-C). Once the surgery is underway, they will be very difficult to identify intraoperatively. No local anesthesia is injected into the transferred tissues or the recipient site. All stages are performed under general anesthesia to avoid the tissue distortion and vasoconstriction-associated fluid and epinephrine injection, which make the intraoperative evaluation of contour and vascularity difficult.

Quarter-inch paper tapes, consolidated with collodion, were placed over the intact left nose to create exact templates of the contralateral normal. Foil patterns are made of the left hemitip and left ala and the left upper lip unit (Fig. 42.3). The left hemitip template was flipped over and repositioned on the right lip to ensure the correct position of the right alar base.

The previous forehead flap was elevated thinly and hinged over, based on the retracted alar rim. Although a large amount of tissue was available as a turnover flap, the stenotic nostril could not be opened along the retracted nostril margin without destroying the hingeover flap’s vascular base (Fig. 42.4). The previous flap was discarded. The stenotic nasal vestibule was then incised at the alar base at right angles to its margin to open the airway (Fig. 42.5A-C).

The subunit principle was applied—if a defect encompasses more than 50% of a convex nasal subunit (the tip or ala) and will be resurfaced with a flap, residual skin within the subunit is excised to resurface the defect as a subunit, rather than as an incomplete patch.

Because all of the ala and the majority of the tip skin were missing or injured, residual normal skin and scar were excised within the entire tip, planning to resurface the right ala and tip as complete subunits. Although the defect extended into the inferior dorsum and sidewall, the borders of these relatively flat subunits are indistinct so the subunit principle does not apply. Additional normal tissue within the dorsal and sidewall subunits is not excised.

When a convex subunit is resurfaced in its entirety, uniform subunit skin quality is maintained and the scars from the border of the flaps lie in the unions between subunits where their reflected light or cast shadows are relatively camouflaged. Most importantly, scar between the raw surface of the flap and the underlying recipient bed contracts, drawing the surface of the flap above the residual normal adjacent skin. When an entire convex

subunit is resurfaced, this inevitable wound contraction is harnessed, in combination with appropriately shaped cartilage grafts, to restore the expected uniform convexity of the tip and ala, rather than a pincushioned patch.

FIGURE 42.2 A-C: A second repair was planned with a three-stage full-thickness forehead flap for cover and lining. The regional units of the nose were marked. The border of the previous forehead flap was outlined. The ideal position of the right alar base was confirmed with a template of the left contralateral upper lip unit.

FIGURE 42.3 1/4-inch paper tapes were applied to the nasal surface to design the left hemitip and heminasal templates, based on the contralateral normal nose. The left hemitip template is flipped over and combined with the heminasal template to design a foil template with the exact dimension and outline of the tip and ala subunits. A foil template of the left normal upper lip unit was also created.

FIGURE 42.4 The previous forehead flap was hinged inferiorly along the healed margin of the nostril. Although vascularized, the airway could not be opened without interfering with its base.

The left alar cartilage was intact, although deprojected. It was advanced and sutured to a septal columellar strut to restore tip projection. A conchal cartilage graft was also fixed to the columellar strut as an anatomic hemitip replacement for the right medial and lateral crura (Fig. 42.6A, B).

A right paramedian full-thickness forehead flap was designed to resurface the right tip and ala, based on a template, created by combining the left contralateral alar template with the left hemitip template (which is flipped over to design the complete tip subunit) (Fig. 42.7A-C). The flap will replace the missing external skin of the tip and right alar subunits in exact dimension. The lining deficit was estimated by measuring the defect on the contralateral normal nostril. About 1.2 to 1.5 cm of lining was missing along the entire inferior right nostril
margin with an additional triangular loss at the alar base created by the release of the stenosis. This second template is drawn as a distal extension of the forehead flap and will be folded for lining.

FIGURE 42.5 A-C: The previous forehead flap and underlying scar was discarded. The skin defect was enlarged by discarding residual normal skin within the tip subunit. The left tip cartilage was intact. The right alar cartilage was missing. The stenosis was incised at the alar base at right angle to the nostril margin to open up the airway.

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