Like the other clefts, Tessier number 11 is in extent to number 3, number 10 is in extent to number 4 and number 9 is in extent to number 5. Lateral clefts
The lateral clefts are the clefts which are positioned horizontally on the face. These are Tessier number 6, 7 and 8. Tessier number 6 runs from the orbit to the cheek bone. Tessier number 7 is positioned on the line between the corner of the mouth and the ear. A possible lateral cleft comes from the corner of the mouth towards the ear, which gives the impression that the mouth is bigger. It’s also possible that the cleft begins at the ear and runs towards the mouth. Tessier number 8 runs from the outer corner of the eye towards the ear. The combination of a Tessier number 6-7-8 is seen in the Treacher Collins syndrome. Tessier number 7 is more related to hemifacial microsomia and number 8 is more related to Goldenhar syndrome. Van der Meulen classification
Van der Meulen classification divides different types of clefts based on where the development arrest occurs in the embryogenesis. A primary cleft can occur in an early stage of the development of the face (17 mm length of the embryo). The developments arrests can be divided in four different location groups: internasal, nasal, nasalmaxillar and maxillar. The maxillar location can be subdivided in median and lateral clefts. Internasal dysplasia
Internasal dysplasia is caused by a development arrest before the union of the both nasal halves.
Treatment
There is no single strategy for treatment of facial clefts, because of the large amount of variation in these clefts. Which kind of surgery is used depends on the type of clefting and which structures are involved. There is much discussion about the timing of reconstruction of bone and soft tissue. The problem with early reconstruction is the recurrence of the deformity due to the intrinsic restricted growth. This requires additional operations at a later age to make sure all parts of the face are in proportion. A disadvantage of early bone reconstruction is the chance to damage the tooth germs, which are located in the maxilla, just under the orbit. The soft tissue reconstruction can be done at an early age, but only if the used skin flap can be used again during a second operation. The timing of the operation depends on the urgency of the underlying condition. If the operation is necessary to function properly, it should be done at early age. The best aesthetic result is achieved when the incisions are positioned in areas which attract the least attention (they cover up the scars). If, however, the function of a part of the face isn’t damaged, the operation depends on psychological factors and the facial area of reconstruction. The treatment plan of a facial cleft is planned right after diagnosis. This plan includes every operation needed in the first 18 years of the patients life to reconstruct the face fully.