Evaluation of Andrews’ analysis as a predictor of ideal sagittal maxillary positioning in orthognathic surgery

Publication date: Available online 22 March 2018
Source:Journal of Oral and Maxillofacial Surgery
Author(s): Cory M. Resnick, Somi Kim, Rachel R. Yorlets, Carly E. Calabrese, Zachary S. Peacock, Leonard B. Kaban
PurposeThere is no universally accepted method for determining the ideal sagittal position of the maxilla in orthognathic surgery. In "Element II" of "The Six Elements of Orofacial Harmony", Andrews used the forehead to define the goal maxillary position. The purpose of this study was to compare how well this analysis correlated with postoperative findings in patients who underwent bimaxillary orthognathic surgery planned using other guidelines. We hypothesized that the Andrews analysis would more consistently reflect clinical outcomes than standard angular and linear measurements.MethodsThis is a retrospective cohort study of patients who had bimaxillary orthognathic surgery and achieved an acceptable aesthetic outcome. Patients with no maxillary sagittal movement, obstructive sleep apnea, cleft or craniofacial diagnoses or who were non-Caucasian were excluded. Treatment plans were developed using photographs, radiographs and standard cephalometric measurements. The Andrews analysis, measuring the distance from the maxillary incisor to the Goal Anterior Limit Line, and standard measurements were applied to end-treatment records. The Andrews analysis was statistically compared to standard methods.ResultsThere were 493 patients who had orthognathic surgery from 2007-2014, and 60 (62% female), with mean age 22.1±6.8 years, met the criteria for inclusion in this study. The mean Andrews distances were -4.8±2.9mm for females and -8.6±4.6mm for males preoperatively, and -0.6±2.1mm for females and -1.9±3.4mm for males postoperatively. For females, the Andrews analysis was closer to the goal value (0mm) postoperatively than any standard measurement (p<0.001). For males, A-N Vert performed best (p<0.001), followed by the Andrews analysis.ConclusionThe Andrews analysis correlated well with the final aesthetic sagittal maxillary position in our sample, particularly for females, and may be a useful tool for orthognathic surgical planning.



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