Leonard 1983 - BJPS - The Forehead Flap

Summary

This article describes a technique for raising a forehead flap that preserves frontalis muscle function and minimizes the secondary forehead defect. The forehead flap is a commonly used reconstructive technique for intraoral defects, but often results in an expressionless forehead with a shiny, adherent skin graft.

Leonard aimed to raise the flap superficial to the frontalis muscle, leaving its innervation and function intact. He notes that some authors advocate dissection deep to the frontalis for vascular supply, while others have mentioned raising it superficial to the muscle. A case done by a colleague with excellent preservation of forehead expression inspired Leonard's interest in perfecting this technique.

Leonard reviewed the anatomy, noting the frontal branch of the facial nerve is at risk within 1cm lateral to the eyebrow's outer end. The flap's pedicle lies above this danger zone. In high-browed individuals, keeping the flap 1.5cm above the brow avoids nerve damage, but violates aesthetic unit principles. In a case involving frontal branch resection, Leonard took a longitudinal biopsy of the frontalis edge, confirming the nerve enters the muscle's deep surface while arteries are superficial.

The technique involves beveling incisions at flap margins for smooth transitions, except perpendicular incisions along the pedicle for easier later closure. Meticulous hemostasis is critical. Dissection starts above the contralateral eyebrow from below upwards until reaching the medial frontalis edge, where the muscle is deficient. Next, dissection proceeds above the ipsilateral brow. Here, branches of the superficial temporal artery in the subcutaneous fat must be preserved. Then the posterior flap margin is dissected forward over the temporal fascia to visualize and protect the main pedicle. Finally, the danger zone above the lateral eyebrow is approached, dissecting just into the subcutaneous fat to avoid nerve damage. The raised flap is left in place while blood pressure normalizes before transfer. The secondary defect is skin grafted before pedicle division. Care must be taken during graft removal to avoid nerve injury.

Leonard states this technique may reduce major objections to traditional forehead flaps - an expressionless forehead with adherent graft. Alternatives like pectoralis major flaps also have disadvantages, and forehead flaps may still offer the best reconstruction in some cases due to thinness, color match, or other factors. Preserving frontalis function minimizes the forehead defect and maintains expressive movement. Ppreserved muscle contraction and frowning after flap elevation was demonstrated.

In conclusion, dissecting forehead flaps superficial to the frontalis muscle preserves innervation and function while still providing the usual blood supply from branches of the superficial temporal artery. This refined technique reduces the secondary forehead defect and maintains facial expression. Leonard presents an elegant solution to a major drawback of an important reconstructive method.