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Craniofacial, Unilateral Cleft Lip Repair

Craniofacial, Unilateral Cleft Lip RepairArticle by Hongshik Han, MD, Nak-Heon Kang, MD and Pravin K Patel, MD

Introduction
The unilateral cleft lip is one of the most common congenital deformities. A large variation in clinical presentation exists, from the near normal-lFooking scar of the minimal incomplete cleft of the lip, the forme fruste, to the more typical wide, gaping cleft lip involving the maxillary alveolus and palate with a splayed nasal ala bridging the gap across the cleft. Perhaps no other congenital deformity significantly alters the facial form as much as a facial cleft. Patients with this deformity typically require the combined short-term and long-term care of several specialists. They may need numerous surgical interventions, from infancy to adulthood, in order to provide them with the necessary function and aesthetics. The treatment goals for such patients include restoration of facial appearance and oral function, improvement of dental skeletal and occlusal relationships, and improvement of speech and psychosocial status.

History of the Procedure
Cleft lip surgery has evolved from a simple adhesion of paired margins of the cleft to an understanding of the various malpositioned elements of the lip and the need for a more complicated geometric reconstruction using transposition, rotation, and advancement flaps. While the key objective in primary repair of the unilateral cleft lip is establishing the anatomical symmetry of the upper lip; today, an equally important goal is incorporating a functional reconstruction of the underlying muscles as part of the initial repair. Additionally, addressing the nasal deformity associated with the cleft lip has become an integral part of the initial lip surgery. The important role of presurgical manipulation of the nasal cartilages, such as with a nasal alveolar molding device, has also become increasingly evident and an adjunctive component of surgery. By addressing all the elements, form and function are improved. The reader is referred to the references cited for a more detailed historic review of the

individual repairs.

Problem
The cleft affects the obvious facial form as an anatomic deformity and has functional consequences, affecting the child’s ability to eat, speak, hear, and breathe. Consequently, rehabilitation of a child born with a facial cleft must involve a multidisciplinary approach and be staged appropriately with the child’s development, balancing the timing of intervention against its effect on subsequent normal growth.

Frequency
The overall occurrence of cleft lip with or without a cleft palate is approximately 1 in 750-1000 live births, making it the second most common congenital deformity (after club foot).

Incidence varies by race, with clefts occurring more commonly in Asians (1 in 500 births), less frequently in Caucasians (1 in 750 births), and even more uncommonly in African Americans (1 in 2000 births). These racial variations in incidence are not observed with the isolated cleft palate.

In terms of gender, the incidence of cleft lip/palate is more common in males. In contrast the incidence of cleft palate alone is more common in females.

The most common presentation is cleft lip and palate (approximately 45%), followed by cleft palate alone (35%) and cleft lip alone (approximately 20%). Unilateral cleft lips are more common than bilateral cleft lips and occur more commonly on the left side (left cleft lip:right cleft lip:bilateral cleft lip = 6:3:1).

The risk of a newborn having a cleft lip increases if a first-degree relative also has a cleft. If one child already has a cleft lip, the chance of a second child being born with the deformity is 4%. If a parent has a cleft lip, the chance of a newborn having a cleft is 7%. If both a parent and a sibling have a cleft lip, the newborn’s risk rises to 15%.

Etiology
Clefting is multifactorial, with both genetic and environmental causes cited. The observation of clustered cases of facial clefts in a particular family indicates a genetic basis. Clefting of the lip and/or palate is associated with more than 150 syndromes. The overall incidence of associated anomalies (eg, cardiac) is approximately 30% (more common with isolated cleft palate). Environmental causes, such as viral infection (eg, rubella) and teratogens (eg, steroids, anticonvulsants), during the first trimester have been linked to facial clefts. The risk also increases with parental age, especially when older than 30 years, with the father’s age appearing to be a more significant factor than the mother’s age. Nevertheless, most presentations are of isolated patients within the family without an obvious etiology.

Pathophysiology
While the normal embryologic development of the face is detailed in Head and Neck Embryology, a brief outline relevant to the formation of facial clefts follows.

Mesenchymal migration and fusion of the primitive somite-derived facial elements (central frontonasal, two lateral maxillary, mandibular processes), at 4-7 weeks gestation, is necessary for the normal development of embryonic facial structures. When migration and fusion are interrupted for any reason, a facial cleft develops along embryonic fusion lines. The embryonic development of the primary palate (lip and palate anterior to the incisive foramen) differs from the secondary palate (palate posterior to the incisive foramen).

The developing processes of the medial nasal prominence, lateral nasal prominence, and maxillary prominences form the primary palate. Fusion occurs, followed by “streaming” of mesodermal elements derived from the neural crest. In contrast, the secondary palate is formed by the fusion of palatal processes of the maxillary prominence alone. The difference in embryonic development suggests the possibility of differing degrees of susceptibility to genetic and environmental influences and accounts for the observed variation in incidences.

Presentation
A wide range of clinical presentation is possible, from the incomplete cleft to the complete cleft involving the lip, alveolus, palate, and nose. The microform cleft (forme fruste) can be characterized by a barely noticeable furrow along the vertical length of the lip with a small vermilion notch and minor imperfections in the white roll. A small component of vertical lip length deficiency and associated nasal deformity may be present.

In addition to the microform cleft, cleft lips are described as being either unilateral or bilateral, and incomplete or complete. The incomplete cleft lip is characterized by the varying degree of vertical lip separation, but by definition has an intact nasal sill, commonly termed the Simonart band.

The complete cleft lip involves the full-thickness defect of the lip and alveolus (primary palate), extends into the base of the nose (no Simonart band exists), and is often accompanied by a palatal cleft (secondary palate). The premaxilla is typically rotated outwardly and projects anteriorly in relation to a relatively retropositioned lateral maxillary alveolar element.

As a consequence of the clefting of the lip, an associated nasal deformity occurs. The structures of the ala base, nasal sill, vomer, and septum are distorted significantly. The lower lateral cartilage on the cleft side is positioned inferiorly, with an obtuse angle as it flattens across the cleft. The alar base is rotated outwardly. The developing nasal septum pulls the premaxilla away from the cleft, and the septum and the nasal spine are deflected toward the noncleft side. The cleft may continue through the maxillary alveolus and palatal shelf, extending to the palatal bone and soft palate.

Indications
Patients born with a cleft lip should undergo surgical repair unless otherwise contraindicated. The goal of reconstruction is to establish normal morphologic facial form and function in order to provide the optimal conditions for the development of dentition, mastication, hearing, speech, and breathing, and psychosocial status.

Relevant Anatomy
Normal lip and nasal anatomy is essential for an understanding of the distortion caused by a facial cleft. The elements of the normal lip are composed of the central philtrum, demarcated laterally by the philtral columns and inferiorly by the Cupid’s bow and tubercle. Just above the junction of the vermilion-cutaneous border is a mucocutaneous ridge frequently referred to as the white roll. Within the red vermilion of the lip is a noticeable junction demarcating the dry and wet vermilion, the increased keratinized portion of the lip that is exposed to air from the moist environment of the labial mucosa.

The primary muscle of the lip is the orbicularis oris, and it has two well-defined components: the deep (internal) and the superficial (external) components. The deep (internal) fibers run horizontally or circumferentially from commissure (modiolus) to commissure (modiolus) and functions as the primary sphincteric action for oral feeding. The superficial (external) fibers run obliquely, interdigitating with the other muscles of facial expression to terminate in the dermis. They provide subtle shades of expression and precise movements of the lip for speech.

The superficial fibers of the orbicularis decussate in the midline and insert into the skin lateral to the opposite philtral groove forming the philtral columns. The resulting philtral dimple centrally is depressed as there are no muscle fibers that directly insert into the dermis in the midline. The tubercle of the lip is shaped by the pars marginalis, the portion of the orbicularis along the vermilion forming the tubercle of the lip with eversion of the muscle.

In the upper lip, the levator labii superioris contributes to the form of the lip. Its fibers, arising from the medial aspect of the infraorbital rim, sweep down to insert near the vermilion cutaneous junction. The medial-most fibers of the levator labii superioris sweep down to insert near the corner of the ipsilateral philtral column and vermilion-cutaneous junction, helping to define the lower philtral column and the peak of the Cupid’s bow.

The nasal muscles are equally important. The levator superioris alaeque arises along the frontal process of the maxilla and courses inferiorly to insert on the mucosal surface of the lip and ala. The transverse nasalis arises along the nasal dorsum and sweeps around the ala to insert along the nasal sill from lateral to medial into the incisal crest and anterior nasal spine. These fibers join with the oblique fibers of the orbicularis and the depressor septi (nasalis), which arises from the alveolus between the central and lateral incisors to insert into the skin of the columellar to the nasal tip and the footplates of the medial crura.

A unilateral cleft thus disrupts the normal termination of the muscle fibers that cross the embryologic fault line of the maxillary and nasal processes, resulting in symmetric but abnormal muscular forces between the normal equilibrium that exists with the nasolabial and oral groups of muscles. With an unrestrained premaxilla, the deformity accentuates with differential growth of the various elements. The alar cartilages are splayed apart and rotate caudally, subluxed from the normal position. Consequently, the nasal tip broadens, the columellar is foreshortened, and the alar bases rotate outwardly cephalad.

Contraindications
Malnutrition, anemia, or other pediatric conditions that result in the patient’s inability to tolerate general anesthesia are contraindications to this procedure. Cardiac anomalies that may coexist must be addressed prior to the lip repair.

Work Cited Here: http://emedicine.medscape.com/article/1279641-overview

 

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