Nasal reconstruction using a paramedian forehead flap within oral and maxillofacial surgery, is a surgical technique to reconstruct different kinds of nasal defects. In this operation a reconstructive surgeon uses skin from the forehead above the eyebrow and pivots it vertically to replace missing nasal tissue. Throughout history the technique has been modified and adjusted by many different surgeons and it has evolved to become a popular way of repairing nasal defects.
The tint of forehead skin so exactly matches that of the face and nose that it must be first choice. Is not the forehead the crowning feature of the face and important in expression? Why then should we jeopardize its beauty to make a nose? First, because in many instances, the forehead makes far and away the best nose. Second, with some plastic juggling, the forehead defect can be camouflaged effectively.
History Probably the first nasal reconstructions using a forehead flap were performed by Sushruta in India during 600 to 700 BC. The method was introduced in Europe in the 15th century. The first English description of the Indian midline forehead rhinoplasty was published in the Madras Gazette in 1793 and later Carpue, an English surgeon, published his experience with two successful median forehead flaps in 1816. The classic median forehead flap supplied by paired supratrochlear vessels was popularized in the United States by Kazanjian in 1947, however, this flap was not optimal because it was not long enough. To solve the problem of the short median forehead flap, its design was modified so that central forehead tissue could be transferred on a unilateral paramedian blood supply.
Indications A forehead flap is usually required if the nasal defect is larger than 1.5 cm, requires replacement of support or lining, or if it is located within the infratip or columella. If the defect is small and superficial it can be resurfaced with a skin graft or it can heal by secondary intention. Limited alar defects can be resurfaced using a nasolabial flap, however, the amount of tissue available from the nasolabial area is limited and the flap is thicker, less vascular, and hair bearing in males. Nasal defects mostly result from excision of (malignant) skin tumours as basal cell carcinoma, squamous cell carcinoma, melanoma, keratoacanthoma, lentigo maligna, lymphoma, and sweat gland carcinoma. Other acquired nasal defects are usually caused by trauma, burns or sepsis. The forehead flap is known as the best donor site for repairing nasal defects because of its size, superior vascularity, skin color, texture and thickness. Especially the color and texture of the forehead skin matches exactly with the skin of the nose. This is why the forehead flap is used so much for nasal reconstruction.
Principles
Vascularisation Vascularisation of the scalp and forehead is supplied by the supraorbital, supratrochlear, superficial temporal, postauricular and occipital vessels. All these vessels are lined vertically and permit safe and effective transfer of the forehead flap on multiple individual vascular pedicles. The pedicle is the anatomic part that resembles the stem of the flap. The perfusion of the paramedian forehead flap comes from three sources: randomly, through the frontalis muscle and through the supratrochlear artery. Because the forehead flap is an axial flap with a pedicle containing its dominant vessel, the pedicle can safely be narrowed to 1 to 1.2 cm.
Flap design
Four types of flap design are historically described in literature: the median forehead flap, oblique forehead flap, sickle flap and vertical paramedian forehead flap. However, the vertical paramedian forehead flap based on the ipsilateral or contralateral supratrochlear vessels has become standard, because it has a low turning point, making it easy to reach the defect without using hair-bearing scalp. Also, primary closing of the proximal forehead is possible as a result of the narrow pedicle. Lateral nasal defects are usually closed with an ipsilateral paramedian forehead flap. Central nasal defects can be reconstructed using either a right- or left-sided forehead flap. The ipsilateral pedicle is closer to the defect than the contralateral pedicle, therefore the flap can be made shorter when using the ipsilateral side. Some experts suggest that a contralateral flap is easier to rotate, but this difference is minimal. The only problem with the contralateral flap is the extra length needed, not the difficulty of the technique. Most foreheads are at least 5 cm long, when measured from eyebrow to hairline. This is usually enough to resurface the entire nose using a vertical paramedian forehead flap design. Still, there are some short foreheads. A forehead is called short when it is shorter than 4.5 cm. When using the forehead flap on a short forehead, there are multiple ways to get the length that is needed. First, the turning point of the flap can be moved down, so that the base of the flap is closer to the nasal defect and a shorter flap can be used to reach the nasal defect. Second, the distal end of the flap can be placed within the hairline. The reconstructed nose will then have some hair on it, but it can be plucked, depilated or lasered.
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