Lip Reconstruction

With any surgical reconstruction, one must take into consideration many factors that affect overall satisfaction in terms of functional and aesthetic results. The lip is no exception. Functionally, the lips serve as borders of the oral commissure, providing adequate access to the oral cavity and contributing to oral competency. Aesthetically, the lips are the focal point for verbal expression and are fundamental to the overall appearance of the face.

Lip reconstruction is not a new concept. Evidence supports that techniques used today were discussed as early as 1000 BC in the sacred texts of Susruta, India. Tagliacozzi originally popularized tissue transfer techniques in the late 16th century. Von Burow first used the technique of skin triangle excisions to facilitate flap advancement in the early 19th century. Shortly thereafter, in 1834, Dieffenbach described the first cheek advancement flap techniques. The late 19th century was a time of the popular contributions of Abbe, Sabattini, and Estlander. The last century is considered to be one of refinement of the above-mentioned principles. Techniques popularized by Karapandzic and Hari and Ohmori highlight the ability to more effectively address the largest lip defects. Karapandzic introduced the myoneurovascular pedicled advancement flap, and Harii and Ohmori performed the microvascular free tissue transfer for lip reconstructions in 1974. ^[1]

This article discusses principles for the reconstruction of all lip defects of traumatic and neoplastic origin. Concepts for cleft lip reconstruction are discussed in the article Cleft Lip.

Frequency

Lip carcinoma is the most common oral cavity malignancy. It is the site of almost 30% of all oral cavity malignancies.

Lip reconstruction techniques are most commonly used in neoplastic disease cases because carcinoma of the lip is the most prevalent location for oral cavity carcinomas. However, traumatic deformities comprise defects that may also require the reconstructions discussed in this article.

Lip defects can be classified according to thickness of the defect (ie, skin or mucosa only, full-thickness) and overall size of the defect. Individual patient factors, such as previous operations, underlying comorbidities, compliance, and mechanisms for the wound defect, may affect choices of reconstruction; therefore, several different options should be available for each defect. Upper and lower lip defects are best described separately. Though the choices of flaps abound, perhaps understanding the principles of a few flaps is best. Becoming familiar with the principles of a few flaps is important because the actual defect size is not often known until immediately prior to reconstruction.

The hexagonal lip aesthetic subunit can be divided into upper and lower divisions. The upper lip is further divided into 2 lateral subunits and a central philtral subunit. The inferior division is divided simply at the vermillion border. In general, entire subunits must be excised and reconstructed to conform to the aesthetic principles of scar camouflage. This system also allows for discussion of each subunit and its reconstructive possibilities.

Several algorithms have been described that match depth, size, and location of a defect with the suggested reconstruction. Although this is an excellent resource in considering potential options, knowledge of both the options and the related benefits and pitfalls of each flap is important. Because prior surgery in the area may have compromised some of the reconstructive options, these algorithms clearly serve only as guidelines. Optimally, the major goals of reconstruction must be addressed; these goals include reestablishment of oral competence, adequate oral aperture and motion, and normal anatomic proportions.

Anatomic considerations, including blood supply, sensation, muscular function, motor innervation, and the topographic subunits, are critical concepts that must be recognized if optimal results are to be achieved.

The lips in repose approximate a hexagon with superior, inferior, and paired superolateral and inferolateral borders. The superior border is the inferior margin of the nose. The superolateral boundaries orient from around the alar sulci to the modioli. The inferolateral boundaries extend downward and medially from the modioli to the mentolabial sulcus.

The junction between external hair-bearing skin and the red hairless surface in the upper lip takes the form of a double-curved Cupid bow, the bilateral apices of which correspond to the lower end of each philtral ridge. The depth of the skin–red lip junction of the lower lip varies greatly in individuals, but invariably some inferomedially directed convexity from the modioli is present.

The glistening, pink, and moist appearance of the free red lip, or vermillion, is due to its covering with a specialized stratified squamous epithelium that is thinnest near the white skin and increases in thickness slightly as the mucosa is approached. The epithelium is grooved with abundant long dermal papillae that carry a rich capillary plexus and sensory innervation, which account for the red lip's characteristic color and high discriminative sensitivity.

Previously, the oral fissure was assumed to be surrounded by a series of complete ellipses of muscle resulting in a sphincter compression of the lip margins. Upon further functional inspection, independent quadrants clearly are apparent. Each quadrant consists of a pars peripheralis and a smaller pars marginalis. The pars marginalis is not limited solely to the vermilion but extends outward. The pars marginalis is located anterior and superior to the most distal portion of pars peripheralis except at the mouth corner where it is located just anterior and inferior to the most distal portion of pars peripheralis, and anterior to the bundle of buccinator muscle. ^[2]

Formally, the orbicularis oris muscle as a whole is composed of 8 segments, each representing a fan with its stem at the modiolus. The region of opposition of marginal and peripheral parts is indicated by the red-white junction ventrally, and the mucosal-red lip junction posteriorly. Accessory muscles of the orbicularis oris complex exist and mainly consist of superior and inferior tractors. Superiorly, these tractors are the zygomaticus minor, the levator labii superioris, and the levator labii superioris alaeque nasi. The depressor labii inferioris and the platysmal pars labialis are the inferior tractors.

Motor innervation is derived from the facial nerve branches. All mentioned muscles receive their neural innervation from the posterior aspect of the facial nerve. The blood supply is derived from superior and inferior labial arteries, which branch from the facial artery superomedially. The mental nerves inferiorly and the supraorbital nerves superiorly provide sensation.

Do not perform closure of any defect after neoplastic excision until margins have been adequately examined. Proceeding with a complex closure prior to establishment of adequate margins can certainly compromise the ultimate result. Soft tissues containing neoplastic cells may be undermined and relocated, ultimately confusing further excision.

Previous operations with possible compromise of labial vessels may be a contraindication to the use of a pedicled labial flap. Therefore, a complete history is essential.