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L-shaped Reduction Malarplasty: Its Geometric Consideration
1Department of Comprehensive Plastic Surgery, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Background:
L-shaped reduction malarplasty is a popular surgery in Oriental population. None of the previews studies investigated the relationship between bone moving and the orientation of the osteotomy lines. This study aimed to illustrate the relationship between zygomatic complex bone moving and the orientation of the osteotomy lines, and to propose a geometric model for surgical planning.
Methods:
Osteotomy lines of L-shaped reduction malarplasty were projected to the coronal plane. Four geometric models were made to analyze the relationship between zygomatic complex bone moving and the orientation of the osteotomy lines. A retrospective study of bone move in L-shaped reduction malarplasty was made. Differences of the data gained by measurement on CT images and the results calculated by the geometric equations were analyzed with a paired t test. Differences were considered statistically significant at a P value less than 0.05. Results consistency was assessed with the Bland-Altman plot.
Results:
Equations analyzing the relationship between zygomatic complex bone moving and the orientation of the osteotomy lines were proposed. The oblique osteomy line affects the downward bone moving, and the direction of the vertical osteotomy lines affects the inward bone moving along with the width of bone removed. A retrospective clinical study included 20 sides of zygoma on ten consecutive patients who underwent L-shaped reduction malarplasty from 2023 to 2024 was made. Statistical analysis shown no statistical significance (P = 0.891) between the data gained by measurement and calculated by the equations. A great accordance was shown by the Bland-Altman plot analyses.
Conclusions:
Orientation of the osteotomy lines affects the zygomatic complex bone moving. Less slant of the oblique osteotomy line is recommended to minimize the downward moving. The two parallel osteotomy lines on the anterior part of the zygomatic bone are recommended to be vertical to achieve precisely operation.
Level Of Evidence Iv:
This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
