Craniofacial Clefts

Congenital craniofacial clefts are distortions of the face and cranium with deficiencies or excesses of tissue that cleave anatomic plans in a linear fashion. Craniofacial clefts exist in varying degrees of severity and in a multitude of patterns. Most craniofacial clefts occur along predictable embryologic lines.

Epidemiology

The precise incidence of craniofacial clefts has not been identified because of their rarity and difficulty in characterized physical findings in mild malformations. The incidence of craniofacial clefts has been estimated to be 1.4-4.9 / 100 000. The intrauterine incidence of facial deformities of any type has been documented to be grater than the incidence at live births. Fetuses of therapeutic abortions between 3-18 weeks of gestation were found to have craniofacial malformation at the rate of 42.5 / 100 000.

Etiology

The majority of craniofacial clefts occur sporadically. However, heredity has a role in the causation of craniofacial clefts in Treacher Collins syndrome and Goldenhar syndrome. Animal and human clinical studies have shown that many environmental factors may contribute to the cause of clefts. Four major categories group these factors;

1. radiation,

2. infection,

3. maternal metabolic imbalance,

4. drugs (anticonvulsants, chemotherapeutics, steroids, tranquilizer, retinoids) and

5. chemicals.

Important aspects of embryologic development of the face take place between 4 and 8 weeks of gestation. During this time, the crown-rump length increases from approximately 3,5 mm to 28 mm. Five prominences (the frontonasal and paired maxillary and mandibular) formed by neural crest migration surround the stomodeum. There is a coordination of cell migration, cellular interaction and apoptosis during a short 4 week period. Failure of this intricate program will result in clefts that usually fall along predictable embryonic lines.

Classifications

Craniofacial malformations are rare and have multiple variations. American Association of Cleft Palate Rehabilitation (AACPR) endorsed a classification system. Craniofacial clefts are separated into four categories on the basis of pathologic locations.

1. Mandibular processes clefts

2. Naso-ocular clefts

3. Oro-ocular clefts (type 1 and 2)

4. Oro-aural clefts

Tessier propsed a classification system based on personal experiences. The clefts are numbered 0 to 14 and follow well defined time zones. The order of description consists of facial clefts from medial to lateral followed by cranial clefts from lateral to medial. According to this classification, clefts describe as number 0 (median cleft face syndrome), number 1 (paramedian facial cleft), number 2 (another form of paramedian cleft) number 3 (oro-naso-ocular cleft), number 4 (oro-ocular cleft), number 5 (oculofacial cleft), number 6 (zygomatic-maxillary cleft) number 7 ( temporo zygomatic facial cleft) number 8 (fronto zygomatic cleft), combination number 6-7-8, number 9 (upper lateral orbital cleft), number 10 (upper central orbital cleft), number 11 ( upper medial orbital cleft), number 12 (cranial extension of number 2 cleft), number 13, number 14 and number 30 cleft.

Management of facial clefts

Management by a multidisciplinary team during the growth period that is up to 18 years or beyond is invariably necessary. Various surgical methods perform depending on the anomalies.