Risk Factors Analysis for Different Types of Unfavorable Fracture Patterns During Sagittal Split Ramus Osteotomy: A Retrospective Study of 2008 Sides.

Abstract

To summarize unfavorable fracture patterns during sagittal split ramus osteotomy (SSRO) and investigate the association with influencing factors. We conducted a retrospective analysis of 1007 patients with 2008 sides of SSRO and classified unfavorable fracture patterns into three types: fracture lines involving the sigmoid notch, condylar process, or coronoid process (Type A); fracture lines extending from the posterior border of the mandibular ramus to the mandibular body or the anterior border of the ramus (Type B); and unfavorable fractures located in the anterior horn of the proximal segment with free fragment (Type C). Logistic regression analysis was used to evaluate factors influencing unfavorable fracture patterns, including sex, age at the time of operation, class of occlusion, presence of the third molar, uni- or bi-maxillary surgery, and the distance from the mandibular canal to the buccal cortex. The distance from the mandibular canal to the buccal cortex was significantly associated with unfavorable fracture patterns during SSRO. The presence of third molars was significantly associated with Type A fractures. The distance from the mandibular canal to the buccal cortex was significantly lower in Type B fractures. We found that the influencing factors for unfavorable fracture patterns varied. Clinicians should pay specific attention to patients with factors for each unfavorable fracture pattern during SSRO. 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 .