Tessier's Cleft Number 6 Revisited: A Series of 26 new Cases and Literature Review of 44

To fix a gray zone left in Tessier's classification of rare clefts with cleft 6 and to give a more comprehensive description of cleft 6 anatomy.

The material used for the research was a series of 26 clinical cases of patients with assessed cleft 6 and 44 cases found out of a literature review with enough data to be useful. The 70 cases were cross-examined by the authors.

The authors are senior craniofacial surgeons working in high-case load department from university centers where the patients are documented and receive primary as well as secondary treatment and follow-up.

The patients were selected out of the series of craniofacial deformities taken care of by the authors' department as rare clefts.

We describe the full spectrum of cleft 6 as an autonomous entity that could present itself in three subtypes: 6a is the most proximal and could be associated with cleft 8. The subtype 6b is medial toward the zygomatic arch and frequently associated with a bone and teeth appendage (frequently described as a "maxillary duplication"). The subtype 6C goes toward the external ear between the helix crus and the auditory meatus.

The Tessier's opinion is that Treacher Collins syndrome was the association of clefts 6, 7, and 8 and is no longer sustainable in the light of modern genetics. Most of the cleft 6 are misdiagnosed in the literature.