Inferior Maxillary Repositioning Remains Stable 1 Year After Surgery but Entails a High Risk of Osteosynthesis Failure

Abstract

Purpose: Inferior maxillary repositioning is among the most unstable orthognathic procedures. The overall purpose of this study was to measure skeletal stability after inferior maxillary repositioning.Method: The authors implemented a retrospective cohort study. The study cohort was derived from all orthognathic patients treated between January 2011 and December 2013 in Odense University Hospital. Inclusion criteria were orthognathic surgery with inferior maxillary reposition in patients with no maxillary segmentation or cleft lip/palate. Exclusion criteria were non-attendance at followup or requiring reoperation before the 1-year follow-up. The primary predictor variable was the time from 1-week follow-up to 1-year follow-up. The primary outcome variable was maxillary skeletal movement. Other variables of interest were age, sex, preoperative occlusal relationship, obtained maxillary movement, and type of surgery (mono-or bimaxillary procedure). Skeletal stability was measured at the centroid, anterior, and posterior nasal spines using the semi-automatic measurement technique. Skeletal stability was clinically defined as less than 2 mm movement in any direction. Positive directions of the 3 axes were right, anterior, and superior. The data were analyzed by mixed model linear regression analysis and 1-sample t-tests.Results: In total, 17 patients were included in the study (mean age 28, 35% female, 59% bimaxillary surgeries). Inferior maxillary repositioning was stable with less than 0.3 mm mean skeletal movement in any direction. Only 1 patient had a relapse of more than 1 mm in the posterior direction and none exceeded 2 mm. However, 3 patients were excluded from this analysis, since they required reoperation during the first year after surgery due to osteosynthesis failure. Conclusion:Inferior maxillary repositioning was stable during the first year after surgery; however, there was a high complication rate (15%). Thus, this procedure may still benefit from use of more rigid patient-specific, printed plates to increase postoperative stability.

What is the angular accuracy of regional voxel-based registration for segmental Le Fort I and genioplasty osteotomies?

“…Orthognathic surgery is a prototypical example of such a surgery. The literature is replete with studies on the accuracy and stability of various orthognathic surgical procedures [1][2][3][4][5][6][7][8] , and from this, valuable information has been derived that is used in everyday clinical practice, in the refinement and modification of existing protocols and in the development of novel methods 1,2,[8][9][10] . However, there has been much less interest in the methods with which accuracy or surgical changes are measured, especially in the surgical literature.…”