Accuracy of Maxillary Repositioning During Orthognathic Surgery

Study Overview
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Brief Summary
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Orthognathic surgery aims to correct jaw position taking into account esthetic and functional criteria (dental occlusion, lip position, breathing...). These surgeries are planned using clinical, radiological and dental cast data. The result of this planning are occlusal splints. Orthognathic surgery had improved in the last decade with 3 dimensions computerized tomography scan (3D CT-Scan) planning and osteosynthesis implants. However the accuracy of the operative results compared to the planned ones has rarely been measured.

Detailed Description
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Orthognathic surgery aims to correct jaw position taking into account esthetic and functional criteria (dental occlusion, lip position, breathing...). These surgeries are planned only after the end of the growing period and in association with orthodontics. It is necessary to wait the end of facial growth to expect a stable result especially concerning mandibular. The age limit seems to be around 15 to 16 years old for retromandibular deformities and around 18 years old for premandibular deformities. These surgeries are planned using clinical, radiological and dental cast data. Occlusal splints are made using all these results; these occlusal splints are used during the orthognathic surgery to maintain bones in the planned position. Since 1993, a navigation system (Orthopilot™) is used, which allow to track jaw position, in real time, with an accuracy around one millimeter and one degree, during orthognathic surgery. This system is routinely used for condyle repositioning after mandibular sagittal split osteotomies; but it is also useful for maxillary navigation and positioning. The investigator propose to measure the accuracy of the operative results compared to the planned ones, using the Orthopilot™ system.

Official Title
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Accuracy of Maxillary Repositioning During Orthognathic Surgery: a Prospective Observational Descriptive Study in Annecy Genevois Hospital

Conditions
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Orthognathic Surgery, Maxillofacial Abnormalities

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients needing orthognathic surgery with mobilization of the maxilla via a Le Fort I osteotomy, alone or associated to a mandibular osteotomy, whatever the indication (poor occlusion, sleep apnea, temporo-mandibular dysfunction...) patient over 16 years old having not expressed any opposition to the collection of his/her personal data for this study (patient him/herself or holder of parental authority in case of patients younger than 18) Exclusion Criteria: pregnancy patients deprived of liberty protected adult patients needing maxillary disjunction

Ages Eligible for Study
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Minimum Age: 16 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Distribution of the translational and rotational shifts of the maxilla between planning and realization | Shifts will be quantified by 6 components (3 in rotation and 3 in translation) in a coordinate system given by Orthopilot™ navigation system. Accuracy of the surgical technic is evaluated by the distribution of the translational and rotational shifts of the maxilla between planning and realization, taking account conformity (when left/right translation is ≤ 1 mm, top/bottom and back/front translations are < 2 mm, frontal rotation is ≤ 1° and axial and sagittal rotations are ≤ 2°), failure (when left/right, top/bottom and back/front translations are > 2 mm, frontal, axial and sagittal rotations are >4°), and non conformity (every other shifts). | during the surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Inter-incisal vector | The inter-incisal vector (that is square root of the sum of each translation shift squared) is calculated by the statistician. It derived from shifts in millimeter and degree measured during surgery by Orthopilot™ navigation system. | during the surgery |