Cleft lip and palate

Clefts of the lip, alveolus, hard and soft palate are the most common congenital abnormalities of the orofacial structures. They frequently occur as isolated deformities but can be associated with other medical conditions particularly congenital heart disease. They are also an associated feature in over 300 recognized syndromes.

All children born with a cleft lip and palate need thorough paediatric assessment to exclude other congenital abnormal­ities. In certain circumstances genetic counselling must be sought if a syndrome is suspected.

Incidence

The incidence of cleft lip and palate is one in 600 (1:600) live births, and 1:1000 live births for isolated cleft palate. The incidence increases in Oriental groups (1:500) and decreases in the black population (1:2000). The highest incidence reported for cleft lip and palate occurs in the Native American tribes of Montana, USA (1:276).

Although cleft lip and palate is an extremely diverse and variable congenital abnormality, several distinct subgroups exist, namely cleft lip with/without cleft palate (CL/P), cleft palate alone (CP) and submucous cleft palate (SMCP).

The typical distribution of cleft types is:

cleft lip alone — 15 per cent;

cleft lip and palate ------45 per cent;

isolated cleft palate — 40 per cent.

Cleft lip/palate predominates in males whereas cleft palate alone appears more common in females. In unilateral cleft lip, the deformity affects the left side in 60 per cent of cases.

Aetiology

Contemporary opinion on the aetiology of cleft lip and palate is that cleft lip and palate (CL/P) and isolated cleft palate have a genetic predisposition and a contributory environmental component. A family history of cleft lip and palate in which the first-degree relative is affected increases the risk to one in 25 live births. Genetic influence is more significant in cleft lip/palate than cleft palate alone where environmental factors exert a greater influence.

Environmental factors implicated in clefting include maternal epilepsy and drugs (e.g. steroids, diazepam, phenytoin), although the benefit of antenatal folic acid supplement to prevent cleft lip and palate remains equivocal.

Although most clefts of the lip and palate occur as an isolated deformity, the Pierre Robin sequence remains the most common syndrome. This syndrome comprises isolated cleft palate, retrognathia and a posteriorly displaced tongue (glossoptosis), which is associated with early respiratory and feeding difficulties.

Isolated cleft palate is more commonly associated with a syndrome than cleft lip/palate and cleft lip alone. Over 150 syndromes are associated with cleft lip and palate, although Stickler (ophthalmic and musculoskeletal abnormalities), Shprintzen (cardiac anomalies), Down’s, Apert’s and Treacher Collins’ are most frequently encountered.

Classification

Any classification for such a diverse and varied condition as cleft lip and palate needs to be simple, concise, flexible, exact but graphic. It must be suitable for computerisation but descriptive and morphological. An example of such a classification is the LAHSHAL system which is able to describe site, size, extent as well as type of cleft (Fig. 37.1).

Complete clefts of the lip, alveolus, and hard and soft palate are designated capital L, A, H and 5, respectively, whereas incomplete clefts are recorded in small letters; microform clefts are documented with asterisks. Hence, LAHSHAL is the anatomical paraphrase of a complete bilat­eral cleft lip and palate. Another example, lahSh, represents an incomplete right unilateral cleft lip and alveolus with a complete cleft of soft palate extending partly on to the hard palate.