Key Features

Cleft lip and cleft palate can be classified as syndromic (15–60%) or nonsyndromic. Syndromic associations include Apert′s, Stickler′s, Treacher Collins′s, and Waardenburg′s syndromes. Cleft lip with or without cleft palate is believed to be genetically distinct from isolated cleft palate. Nonsyndromic clefts may be secondary to exposure to teratogens (e.g., ethanol, anticonvulsants, steroids, vitamin A excess). Likewise, maternal and intrauterine factors such as gestational diabetes, smoking, or amniotic bands may play a role.

Typically, cleft palate management is done by a team including surgeons, dentists, orthodontists, speech pathologists, and audiologists.

Embryology of the Lip and Palate

The palate is embryologically divided into the primary (the maxillary alveolus and palate anterior to the incisive foramen), and secondary (originating posterior to the incisive foramen and terminating at the uvularis) components. Fusion of the paired median nasal prominences (MNPs) gives rise to the primary palate. This process initiates the separation of the oral from the nasal cavity. The coalescence of the MNPs forms the central maxillary alveolar arch, central and lateral incisors, anterior hard palate, premaxilla, philtrum of the upper lip, columella, and nasal tip. The genesis of the central upper lip occurs in association with the primary palate. The frequent association of these deformities is not unexpected. The remainder of the upper lip, lateral to the philtrum, is formed by fusion of the paired MNPs medially with the maxillary processes laterally.

Formation of the secondary palate is initiated by contact of the nasal septum to the lateral palatal shelves at the incisive foramen. The medialization of the palatal shelves then occurs in an anterior to posterior direction. The midline tongue represents a barrier to this medialization. Development of the mandible results in anterior displacement of the tongue, allowing normal growth of the palatal shelves. Failure of this process results in the Pierre Robin′s sequence (micrognathia, relative macroglossia, and U-shaped cleft palate); see also Chapter 8.8.

There is not only an embryologic structural division of the palate, but a temporal one as well. The primary palate forms during weeks 4 to 7 of gestation. The secondary palate begins development after completion of the primary palate and occurs during weeks 8 to 12 of gestation.

Epidemiology

Cleft lip and palate are the most common congenital malformations of the head and neck. The incidence of cleft lip with or without cleft palate in the United States is 1:1,000 newborns and varies according to race, with the highest incidence in Native Americans and a male/female ratio of 2:1. The incidence of cleft palate is 1:2,000 and is equal across ethnic groups, with a male/female ratio of 1:2.

Clinical

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