Ritchie Collin A, Hayes Lauren, Zhai Guihua, Kinard Brian E
Resident-in-Training, Department of Oral and Maxillofacial Surgery, University of Alabama at Birmingham School of Dentistry, Birmingham, AL.
Dental Student, University of Alabama at Birmingham School of Dentistry, Birmingham, AL.
J Oral Maxillofac Surg. 2025 Jun;83(6):670-680. doi: 10.1016/j.joms.2025.03.002. Epub 2025 Mar 10.
The lingual split scale (LSS) following sagittal ramus osteotomy (SRO) is an objective scale where LSS1 to 3 are variations of a favorable split, while LSS4 is an unfavorable split. LSS influences postoperative bone overlap, posterior interferences, and fixation methods. There is currently no study evaluating LSS following SRO using the low and short medial osteotomy modification.
The purpose of this study is to describe the lingual fracture pattern of the distal segment through the LSS following SRO using the low and short medial osteotomy modification.
STUDY DESIGN, SETTING, AND SAMPLE: A retrospective cohort study of subjects undergoing SRO with the low and short medial osteotomy by a single surgeon at The University of Alabama at Birmingham between February 2020 and July 2024. Subjects with incomplete records were excluded.
Anatomic predictor variables were ramus width and length and the vertical height of the lingula. Procedural predictor variables were height and angle of the medial osteotomy, medial osteotomy relative to the lingula and to the mandibular canal, and third molar removal at the time of SRO.
The primary outcome variable was the LSS. LSS1 to 3 are variations of a favorable SRO split, while LSS4 is unfavorable.
Covariates include age, sex, and previous mandibular osteotomies.
The significance level was defined as P < .05. Multivariate regression analyses assessed variables that were near statistically significant (P < .2). Hemimandibles were correlated and the subject factor was accounted for using generalized estimating equations.
The study sample had 210 subjects (419 hemimandibles). LSS variations of favorable splits resulted in 263 (62.8%) vertical fractures (LSS1), 8 (1.9%) horizontal fractures (LSS2), and 139 (33.2%) fractures along the mandibular canal (LSS3). Nine (2.2%) unfavorable splits (LSS4) were present. No variables were found to be significantly associated with unfavorable fractures (LSS4).
SRO using the low and short medial osteotomy resulted in predictable LSS patterns. Favorable fracture patterns (LSS1 to 3) were present in 97.8% (410) of SROs, while unfavorable fracture patterns (LSS4) were present in 2.2% (9). No variables were identified to be significantly associated with unfavorable fracture (LSS4).
矢状劈开下颌支截骨术（SRO）后的舌侧劈开分级（LSS）是一种客观分级，其中LSS1至3为有利劈开的变异类型，而LSS4为不利劈开。LSS会影响术后骨重叠、后方干扰及固定方法。目前尚无研究使用低位短内侧截骨改良术评估SRO后的LSS。
本研究的目的是通过使用低位短内侧截骨改良术的SRO后的LSS来描述远心骨段的舌侧骨折模式。
研究设计、设置和样本：对2020年2月至2024年7月期间在阿拉巴马大学伯明翰分校由单一外科医生进行低位短内侧截骨术的SRO患者进行回顾性队列研究。排除记录不完整的患者。
解剖学预测变量为下颌支宽度和长度以及舌骨的垂直高度。手术预测变量为内侧截骨的高度和角度、相对于舌骨和下颌管的内侧截骨以及SRO时的第三磨牙拔除情况。
主要结局变量为LSS。LSS1至3为有利SRO劈开的变异类型，而LSS4为不利类型。
协变量包括年龄、性别和既往下颌骨截骨术。
显著性水平定义为P < 0.05。多变量回归分析评估接近统计学显著性（P < 0.2）的变量。半侧下颌骨具有相关性，并使用广义估计方程考虑个体因素。
研究样本有210名患者（419个半侧下颌骨）。有利劈开的LSS变异导致263例（62.8%）垂直骨折（LSS1）、8例（1.9%）水平骨折（LSS2）和139例（33.2%）沿下颌管的骨折（LSS3）。存在9例（2.2%）不利劈开（LSS4）。未发现有变量与不利骨折（LSS4）显著相关。
使用低位短内侧截骨术的SRO导致可预测的LSS模式。97.8%（410例）的SRO出现有利骨折模式（LSS1至3），而2.2%（9例）出现不利骨折模式（LSS4）。未发现有变量与不利骨折（LSS4）显著相关。
