Cleft lip (harelip)

Facial clefts may occur along any plane on the face where embryonic processes normally join and fuse. Thus we may recognize such anomalies as the oblique and transverse facial clefts, which extend from the upper lip or ala of the nose to the eye and from the angle of the mouth to the ear, respectively. The most important of the facial clefts, however, is the cleft lip, mandibular or maxillary.

The mandibular cleft lip is an extremity rare condition which occurs in the midline of the lower lip and arises owning to failure of union of the mandibular processes at this site. Only the lip may be involved or, occasionally, both the lip and the jaw.

The maxillary cleft lip is the more common and more important of the lip clefts. It has been suggested that this cleft is due not to an actual lack of union оf processes, but rather to a failure of the connective tissue to penetrate the united epithelium with the result that a continuous structure is not formed. Since the line of union and fusion normally occurs on either side of the midline, with a single median structure present that is derived from the median nasal process, it is obvious that the maxillary cleft may be a unilateral or a bilateral defect, but not a midline one. Occasionally, however, a portion of the median nasal process is completely absent, and the resulting cleft does appear in the midline.

Etiology. The etiology of the cleft lip is undoubtly a varied one with many interesting ramifications. Heredity is one of the important factors to be considered. Numerous clinical studies have shown that the incidence of cleft lip in children born to similarly affected parents may be as high as 45 per cent. Nutritional disturbances are also of importance.

Clinical features. The maxillary cleft lip may present a varied clinical picture depending upon the severity of the condition. A classification of such clefts according to appearance is as follows:

1) unilateral incomplete (33%);

2) unilateral complete (48%);

3)bilateral incomplete (7%);

4) bilateral complete (12%).

As the names would indicate, the unilateral cleft lip involves only one side of the lip, the bilateral, both sides of the lip. The latter type has given rise to the term "harelip", which is now frequently applied to all cleft lips. The incomplete cleft extends for a varying distance toward the nostril and frequently involves the palate as well. The complete cleft extends into the nostril and even more commonly involves the palate also.

The cleft lip and cleft palate are somewhat more common in boys than in girls, and the lip cleft occurs three times more frequently on the left side than on the right.

Treatment. Most cases of cleft lip may be surgically repaired with excellent cosmetic and functional results. It is customary to operate before the patient is one month of age or at a time when he has regained his original birth weight and is still gaining.

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