Chapter 302 Cleft Lip and Palate
Clefts of the lip and palate are distinct entities closely related embryologically, functionally, and genetically. Although there are a variety of theories, it is commonly thought that cleft of the lip appears because of hypoplasia of the mesenchymal layer, resulting in a failure of the medial nasal and maxillary processes to join. Cleft of the palate appears to represent failure of the palatal shelves to approximate or fuse.
Incidence and Epidemiology
The incidence of cleft lip with or without cleft palate is ∼1/750 white births; the incidence of cleft palate alone is ∼1/2,500 white births. Clefts of the lip are more common in males. Possible causes include maternal drug exposure, a syndrome-malformation complex, or genetic factors. Although both appear to occur sporadically, the presence of susceptibility genes appears important. There are ∼400 syndromes associated with cleft lip and palates. There are families in which a cleft lip or palate, or both, is inherited in a dominant fashion (van der Woude syndrome), and careful examination of parents is important to distinguish this type from others, because the recurrence risk is 50%. The IRF6 gene is responsible for the van der Woude syndrome and some cases of nonsyndromic clefts. The severity of the disease is independent of predisposing genes. Ethnic factors also affect the incidence of cleft lip and palate; the incidence is highest among Asians (∼1/500) and Native Americans (∼1/300), and lowest among blacks (∼1/2500). The incidence of associated congenital malformations (chromosomal aneuploidy, holoprosencephaly) and of impairment in development is increased in children with cleft defects, especially in those with cleft palate alone. The risks of recurrence of cleft defects within families were discussed in Chapters 72 and 75.
Clinical Manifestations
Cleft lip can vary from a small notch in the vermilion border to a complete separation involving skin, muscle, mucosa, tooth, and bone. Clefts may be unilateral (more often on the left side) or bilateral and can involve the alveolar ridge (Fig. 302-1).
Figure 302-1 Non-syndromic orofacial clefts. A, Cleft lip and alveolus. B, Cleft palate. C, Incomplete unilateral cleft lip and palate. D, Complete unilateral cleft lip and palate. E, Complete bilateral cleft lip and palate.
(From Shaw WC: Orthodontics and occlusal management, Oxford, England, 1993, Butterworth-Heinemann.)
Isolated cleft palate occurs in the midline and might involve only the uvula or can extend into or through the soft and hard palates to the incisive foramen. When associated with cleft lip, the defect can involve the midline of the soft palate and extend into the hard palate on one or both sides, exposing one or both of the nasal cavities as a unilateral or bilateral cleft palate. The palate can also have a submucosal cleft indicated by a bifid uvula, partial separation of muscle with intact mucosa, or a palpable notch at the posterior of the palate.
Treatment
A complete program of habilitation for the child with a cleft lip or palate can require years of special treatment by a team consisting of a pediatrician, plastic surgeon, otolaryngologist, oral and maxillofacial surgeon, pediatric dentist, prosthodontist, orthodontist, speech therapist, geneticist, medical social worker, psychologist, and public health nurse. The child’s physician should be responsible for seeking the coordinated use of specialists and for parental counseling and guidance.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
