Midface Osteotomies in Syndromic Synostoses

Abstract

The midface hypoplasia in syndromic craniosynostosis causes aesthetic problems, proptosis, upper airway restriction, pathologic maxillary-mandibular relationship with occlusal disturbance, pathology of speech, chewing and swallowing. The necessary advancement of the whole midface with an osteotomy in the LeFort III fracture lines was described by Tessier in 1967. Bone was interpositioned in the gaps. Modifications have been employed since. The combination of LeFort III advancement and additional forehead advancement was already addressed by Tessier. The necessity of occlusal adaptation with an additional LeFort I osteotomy was shown by Obwegeser in 1969. The problem of the different necessary amount and direction of movement of the midface portion and the zygoma was addressed by Converse and Telsey in 1971 by a tripartite osteotomy of the midface. The arguments have been raised again and a solution with osteotomy and distraction offered by Hopper et al. in 2013. Through the introduction of miniplate osteosynthesis former published procedures were facilitated. The introduction of distraction osteogenesis in midface procedures (Cohen et al. 1995) brought a new tool which is favoured today for major amount of movements due to the possible soft tissue adaptation. This latter method has also been introduced to the repeated discussion of one- or two-stage procedures for cranial vault expansion itself and for necessary cranial and midface correction. The morbidity of one-stage procedures to advance the midface and forehead (Arnauld et al. 2004, 2007; Dunaway et al. 2012) with reported CFS leaks, frontal bone necrosis and infection leads the author to prefer to separate the procedures if possible. The possible or gained amount of advancement is reported to be greater in distraction procedures of the midface (Fearon 2001; Engel et al. 2019) but also for cranial vault procedures (Spruijt et al. 2016). To get the most of the possible enlargement or advancement, this is evident. But for cranial vault expansion dorsal and ventral advancements can be combined and for the midface in adult patients the necessary amount of change is defined and may well be gained by a one-step surgery without having the patient wear a distractor for months. The following clinical examples give an overview of possible combinations and their indication. The functional considerations for midface osteotomies in syndromes cases of craniosynostosis are discussed. The access for the LeFort II and III osteotomies are then shown with dissections from the anatomical lab and clinical examples. The LeFort III osteotomy lines are demonstrated. This is followedny a demonstration of a LeFort III procure in the lab. Clinical examples of LeFort III osteotomies and their combinations with LeFort I and II osteotomies follow. Conventional osteotomies with osteosynthesis and distractions are shown.