Anatomy of the Le Fort I Segment: Are arterial variations a potential risk factor for avascular bone necrosis in Le Fort I osteotomies?

Abstract

Background and objectives: Osteotomies of the Le Fort I segment are routine operations in orthognathic surgery with low complication rates. In this context ischemic complications are, with an occurrence of about 1% rare, but can have severe consequences. These ischemic complications range from gingival retraction and/or loss of tooth vitality to avascular bone necrosis of the mobilized Le Fort I segment. Anatomically the blood supply of the Le Fort I segment is mainly based on the ascending palatine, the ascending pharyngeal, the descending palatine artery and smaller arteries that reach the alveolar process from the buccal side. The aim of this study was to investigate the blood supply and special arterial variants of the Le Fort I segment responsible for arterial hypoperfusion or ischemic avascular necrosis after surgery. Material and methods: A total of 30 halved human cadaver head specimens, preserved with a high-quality embalming method were selected according to defined inclusion and exclusion criteria. All specimens were subjected to arterial latex injection for improved visibility. The arterial anatomy of the Le Fort I segment was analyzed after the ascending palatine and ascending pharyngeal arteries were completely dissected until the submicroscopic level by clinical and anatomical specialists. Dissection was performed using surgical standard methods and a dissection microscope. In all specimens the arterial variants of the Le Fort I segment as also the arterial diameters measured at two points (D1: origin and D2: palate-entry of artery) were evaluated to categorize the occurring types of arterial variations. Results: The typical known palatine vascularization pattern was apparent in 90% of all specimens, in which the ascending palatine artery (D1: 1,2mm ± 0,34mm; D2: 0,8mm ± 0,34mm) and ascending pharyngeal artery (D1: 1,3mm ± 0,58mm; D2:

Date of Award	2018
Original language	English
Awarding Institution	Medical University Graz
Supervisor	Wolfgang Zemann (Supervisor) & Andreas Weiglein (Co-supervisor)