Nasal Reconstruction Including Forehead Flaps
SOURCE: Dept. of Otolaryngology, UTMB, Grand Rounds
DATE: March 20, 1996
RESIDENT PHYSICIAN: John Yoo, M.D.
FACULTY: Karen H. Calhoun, M.D.
SERIES EDITOR: Francis B. Quinn, Jr., M.D.

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"This material was prepared by resident physicians in partial fulfillment of educational requirements established for the Postgraduate Training Program of the UTMB Department of Otolaryngology/Head and Neck Surgery and was not intended for clinical use in its present form. It was prepared for the purpose of stimulating group discussion in a conference setting. No warranties, either express or implied, are made with respect to its accuracy, completeness, or timeliness. The material does not necessarily reflect the current or past opinions of members of the UTMB faculty and should not be used for purposes of diagnosis or treatment without consulting appropriate literature sources and informed professional opinion."

Introduction

Various deformities of the nose can be brought about due to trauma, as well as iatrogenically through the excision of skin malignancies via Mohs microsurgery. Just as many techniques have evolved to repair those various deformities, but a set of general principles guides the reconstruction of the nose with loss of soft tissue and/or underlying framework.

First, since the defect belongs to the patient, it is incumbent on the surgeon to determine, “What does the patient want?” Some patients desire as much as can be done in order to obtain a normal as possible nose even if it means multiple staged procedures with multiple hospitalizations. Other patients desire the bare minimum, such as leaving the defect alone and allowing the defect to heal by secondary intention or skin grafting the wound, even if this bare minimum will produce a suboptimal cosmetic result.

Next, the defect must be analyzed in terms of which tissues are missing, since nasal tissue must be replaced by like tissue in order to effect the best cosmesis. The nose is by and large made up of three layers: the thin, vascular nasal mucosa, the nasal framework consisting of cartilage or bone, and the overlying skin and soft tissues of the nose.

Reconstructive techniques must also take into account the varying thickness of nasal skin depending on the location. The skin of the upper two thirds of the nose is thin, mobile, and has fewer sebaceous glands, whereas the skin over the lower one third is thicker, filled with sebaceous glands, and lacks mobility.

In addition to replacing the missing tissues, however, the nasal contours, highlights, and shadows must also be restored. In order to do this, the nose must be analyzed with regards to the topographic nasal subunits. The nose is divided into 9 subunits: dorsum, 2 nasal side walls, tip, 2 ala, 2 soft tissue triangles, and the columella. Of these, 5 of them are convex (dorsum, columella, tip, and 2 nasal ala) and 4 are concave (2 sidewalls and 2 soft tissue triangles). In order to maintain these concavities and convexities, it is usually best to repair the nasal defect with a different flap or graft technique for each subunit. If a defect involves more than 1/2 of a nasal subunit, the rest of that subunit is excised to achieve better cosmesis. Incisions should be placed along the midline, at the subunit boundaries, and along the lines of minimal tension (vertical in glabella and horizontal over the rest of the nose) to maximize scar camouflage.

The patient should be questioned regarding any intercurrent illnesses as well as previous surgeries. Especially important is whether the patient has a smoking history or any peripheral vascular disease which may compromise the cutaneous vascular supply of the flaps used for reconstruction.

Anatomy

The framework and underlying support of the nose is provided by the nasal bones, upper and lower lateral cartilages, and indirectly by the septum. The blood supply of the nose is provided by the alar and septal branches of the facial artery to the ala and lower septum, respectively. The dorso-lateral areas are nourished by the dorsal nasal branch of the ophthalmic artery and the infraorbital branch of the maxillary artery. The superior labial and angular branches of the facial artery supply the lower and upper nose. The anterior facial and ophthalmic veins provide the venous drainage of the nose. The lymphatics of the anterior nose drain into the submandibular nodes and the rest of the nose drains into the parotid and upper deep cervical lymph nodes.

Techniques for Repair (by subunit)

The actual reconstruction for each patient’s nasal defect must be individualized and tailored to optimize cosmesis, but at all times following the general guidelines as outlined above. However, a systematic guide to the the repair of nasal defects has been published by Larrabee and Sherris and addresses each subunit separately as per the topographic subunit principle.

1. DORSAL SUBUNIT

For superficial defects less than 2.0 cm in size that are vertical or round, the defect can be repaired by primary closure, single transposition flap, or a bilobed flap. For superficial defects less than 2.0 cm that are horizontal, the defect can be repaired by primary closure or a glabellar flap. For defects that are greater than 2.0 cm or are deep, a forehead flap should be used for reconstruction.

2. SIDEWALL SUBUNIT

For defects in the medial canthal area that are less than 1.0 cm, primary closure, FTSG, secondary intention, or a glabellar flap can be used. For medial canthal area defects greater than 1.0 cm, secondary intention or a glabellar flap can be used. In other areas of the sidewall, a modified bilobed flap is used for defects less than 2.0 cm, a superiorly based melolabial flap for defects greater than 2.0 cm, and a forehead flap for defects that are greater than 2.0 cm and/or are deep.

3. TIP SUBUNIT

For superficial defects less than 1.5 cm, primary closure, delayed FTSG, or bilobed flap can be used. For superficial defects 1.5-2.5 cm in size can be repaired with a two stage melolabial flap. If the defect is superficial, but greater than 2.0 cm or if the defect is deep involving underlying cartilage or nasal lining, then a forehead flap should be used .

4. SOFT TISSUE TRIANGLES

The defect of the soft tissue triangles should be allowed to granulate to avoid unsightly notching.

5. COLUMELLA SUBUNIT

Skin only defects of the columella can be repaired by secondary intention or be FTSG. For defects involving both skin and cartilage, a composite graft of lobule and cartilage can be used if the vascular supply is good, and a two stage melolabial flap if the vascular supply is compromised.

6. ALAR SUBUNIT

For superficial defects less than 1.0 cm in size, FTSG can be used (secondary intention may cause excessive alar retraction). For superficial 1.0-2.0 cm defects, a bilobed flap, two stage melolabial flap, or a nasofacial groove flap can be used. For full thickness alar defects less than 1.5 cm, a composite graft of skin and cartilage can be used to reconstruct. For full thickness alar defects greater than 1.5 cm, reconstuction can be performed using the melolabial flap or a forehead flap.

Full thickness skin graft

Skin grafts work well for defects involving thin nasal skin or those subunits that are concave. These areas include the columella, sidewalls, dorsum, and soft triangles. FTSG’s blend in well in defects of the upper 2/3 of the nose. They can be harvested anywhere, but the best donor site for the reconstruction of the superficial defects is preauricular skin where 2.0 to 2.5 cm grafts can be taken. The underlying recipient area must be well vascularized and quilting sutures must be placed to avoid sheering.

Bilobed flap

The Zitelli modification of the bilobed flap is a useful tool for the reconstruction of nasal defects, particularly if the defect is between 0.5-1.5 cm in diameter in the thick-skinned part of the nose. The modification allows for only 45-50 degrees of rotation for each lobe of the flap (rather than the original 90) for a total arc of rotation of 90-100 degrees (rather than the original 180). The smaller arc of rotation poses a lesser problem with a standing cone defect. A triangle of skin equal in length to one radius of the defect is excised to the pivot point. The second lobe of the flap should be brought from the loose skin of the upper 2/3 of the nose. As per Dr. Burget, the bilobed flap should be based laterally for defects of the tip, and medially based for the defects of the ala.

Glabellar/Finger flap

A rotational flap utilizing the lax skin of the glabella can be used to fill in defects of the upper 1/3 of the nose. A midline transposition flap (finger flap) can also repair defects of the upper 1/3 of the nose, but can also address defects if the medial canthal area as well. A standing cone in the inferior rotational area can be trimmed without compromising the blood supply. In both flaps, the donor site is closed primarily without dificulty. Melolabial flap The superiorly based melolabial flap can be used to repair defects greater than 1.5 cm on the ala. This flap is nourished by the branches of the facial and angular arteries that perforate the levator labii muscle near the ala and then extend laterally. Because of this hearty blood supply, the proximal pedicle need not be wide. The flap is elevated in a plane superficial to the facial musculature and can be thinned prior to insetting. This flap can be rolled onto itself (with a cartilage graft placed at the most inferior end to prevent alar retraction) to provide inner nasal lining if none are available. The donor site can be closed along the melolabial crease. At 3 weeks post-operatively, the pedicle can be divided, trimmed, and thinned to close the remnant donor site and the lateral flap bed.

An inferiorly based variation of the this flap can be used to repair small defects of the ala and can be useful because of its use of the nose/cheek boundaries.

Paramedian Forehead Flap

The forehead is a source for abundant donor tissue available for large and/or deep nasal defects. The paramedian forehead flap has a hearty blood supply in a vertical orientation provided primarily by the supratrochlear vessels and to a lesser extent, the supraorbital and dorsal/angular branches of the facial artery. The supratrochlear artery exits the orbital septum and crosses the orbital rim deep to the orbicularis oculi and superficial to the corrugator muscles. The supratrochlear vessels travel 2 cm lateral to the midline and superficial to the frontalis muscle.

The precise location of the supratrochlear artery is identified with a pencil doppler, so that the base of the flap can be narrowed to approximately 1.0-1.5 cm. A base that is too wide can strangulate the flap as it twists to reach the recipient bed or limit the length of the flap.

The shape of the distal flap is planned with the use of a foil template taken of the contralateral uninvolved side (*remember to flip the template over for the mirror image of the defect*). A suture or gauze measured from the pivot point to the most distal portion of the nasal defect is used to determine if the flap is going to be long enough. The flap is elevated in a subgaleal plane and just above the periosteum inferiorly to avoid injurying the vascular pedicle.

Prior to insetting the flap, the nasal lining and the underlying framework are reconstructed, and any remaining portions of the subunit(s) are excised. To match the thickness of the defect, the distal end of the flap may be thinned before suturing into place. However, thinning of the distal flap should be avoided at the primary repair in a smoker due to compromised blood supply. The length of the flap can be increased by 1.5 cm by extending the flap into the scalp or across the orbital rim. Regrowth of hair can be prevented by clipping the bulbs of each hair follicle if extended into the scalp.

If the defect to be reconstructed also involves the nasal lining, the forehead flap can be harvested with the underlying pericranium 2 cm beyond the confines of the distal flap attached to the forehead flap, in a flap designed by Seikaly. Once the flap and its pericranium is elevated, the pericranium can be separated from the overlying skin and sutured into place to replace the nasal lining. Next, the cartilaginous framework can be inserted inset superficial to the pericranial flap, followed by the placement of the skin of the forehead flap.

The donor site can usually be closed primarily after undermining the surrounding skin, but healing by secondary intention or STSG can be used if closure is not possible. The forehead flap pedicle can be divided 3 weeks post-operatively under local anesthesia. The proximal portion of the flap is trimmed/thinned and used to fill in the V-shaped donor defect and trimming/thinning of the distal flap/nasal dorsum is performed to obtain maximal cosmesis of the distal portion.

Nasal lining

Nasal defects involving all three layers require that the deepest layer (nasal mucosa/vestibular skin) be reconstructed. Since this tissue is thin, soft, and vascular, the optimal donor tissue should be similar in character. The nasal lining can be provided by skin grafts, local turn-in flaps, or nasolabial flaps, but the best donor tissue is uni-pedicled or bi-pedicled intranasal tissues such as from the vestibule, middle vault, or the septum. In small full thickness defects of the alar margin, the lining can be replaced by freeing the vestibular skin from its attachment superiorly and rolling it inferiorly and outward like the hem of a skirt until it lines the margin. In addition, if a paramedian forehead flap is used to reconstruct a defect and nasal lining is required, pericranium associated with the distal flap can be used to replace the nasal lining.

Framework

When the nasal defect involves the underlying bone and cartilage framework, like tissues must be used to replace them. Bone may be obtained from the cranial, iliac, or costal bone. Cartilage from the septum, conchal, or costal areas may be obtained to recreate the cartilaginous nasal framework. Because of the close proximity to the surgical field, the conchal and septal cartilages are more widely used. The conchal cartilage has the advantage of having inherent curves that more closely mimic the shape of the alar cartilages. The septal cartilage has to be weakened at certain points in order to bend, but is more easily carved due to its hyaline nature.

Conchal cartilage is harvested by making an incision medial to the rim of the conchal bowl, elevating the overlying mucoperichondrium, excising the conchal cartilage, repairing the incision, and placing a bolster on both sides of the conchal bowl.

Burget recommends even placing cartilage grafts in those parts of the nose that normally contain no cartilage (such as the alar lobule) in order to impart stability to the overlying soft tissue reconstructions.

References

Burget, GC and Menick, FJ. Aesthetic reconstruction of the nose. Mosby-Year Book: St.Louis, MO. 1994.

Larrabee, WF and Sherris DA. Principles of facial reconstruction. Lippincott-Raven publishers: Philadelphia, PA. 1995.

Jackson, IT. Local flaps in head and neck reconstruction. C.V. Mosby Co.: St.Louis, MO. 1985.

Burget, GC. Nasal restoration with flaps and grafts in: Head and neck surgery-Otolaryngology edited by Byron J. Bailey. J.B.Lippincott Co.: Philadelphia, PA. 1993.

Stucker, FJ and Shaw GY. Reconstructive rhinoplasty in: Otolaryngology-Head and neck surgery edited by Charles Cummings. Mosby-Year Book: St.Louis, MO. 1993.