Craniomaxillofacial Deformitites / Sleep Disorders / Cosmetic Surgery
Does the Posterior Bending Osteotomy in Bilateral Sagittal Split Osteotomy Affect the Condyle Position in Asymmetric Patients?

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Purpose

To measure and compare changes in postoperative condylar position following bilateral sagittal split osteotomy in patients with asymmetry treated using a posterior bending osteotomy (PBO) and conventional methods (shaving of premature contacts).

Methods

Participants were randomized to either the PBO or conventional group. The inclusion criteria were the need for bilateral sagittal split osteotomy or bimaxillary asymmetric surgery (menton deviation >4 mm).

The primary outcome variable was changes in the condylar position in the axial, coronal, and sagittal planes 6 months after surgery, whereas the secondary outcome variable was changes in temporomandibular joint symptoms. Covariates included surgery type, deformity type, age, and sex. Categorical and numerical variables were analyzed using Fisher exact χ2 test and 2-way analysis of covariance.

Results

The study sample comprised 42 patients with a mean age of 23.3 years; 57.5% were women. The alteration in the coronal condyle angle was 0.8⁰ ± 0.86⁰ in the PBO and 2.72⁰ ± 0.81⁰ in the conventional group. The differences in the condylar position in the coronal plane were not statistically significant (P = .129). The alteration in the axial condyle angle was 2.31⁰ ± 1.74⁰ in the PBO group and 5.65⁰ ± 1.65⁰ in the conventional group.

The alteration in the sagittal plane was 0.44⁰ ± 1.52⁰ in PBO and 0.47⁰ ± 1.44⁰ in the conventional group. Alterations in axial (P = .194) and sagittal (P = .976) condylar positions were insignificant. In the conventional group, statistically significant differences were found in the axial (P = .002) and coronal (P = .002) planes, and the condyle turned inward in both planes. There were no statistically significant differences between the groups or within the groups in the sagittal plane (P > 0,5). In PBO and conventional groups, joint noise examination revealed positive results in 11 and 6 patients preoperatively and 1 and 2 patients postoperatively, respectively. A statistically significant decrease in joint noise was detected in the PBO group (P = 0,04). The maximum mouth opening without pain was 5.95 ± 1.47 in the PBO group and 7.91 ± 1.39 in the conventional group, respectively. The alteration was not statistically significant between the groups but was significant within the groups (P < .001).

Conclusions

PBO effectively prevents premature contact between mandibular segments in facial asymmetry.

Section snippets

Study Design and Sample Description

This prospective, randomized, controlled study followed the Declaration of Helsinki on Medical Protocol and Ethics and was approved by the Local Ethics Committee of Erciyes University (2019\17). The surgical procedure and possible undesirable conditions were explained to all patients in detail, and informed consent was obtained. The study included patients aged ≤18 to 30 scheduled for asymmetric orthognathic surgery due to Class 2 or Class 3 dentofacial deformity between 2019 and 2020 at the

Results

The sample comprised 42 participants (24 women and 18 men; mean age, 23.3). The patients were randomly divided into 2 groups, PBO (n = 20, 47.6%) and conventional (n = 22, 52.4%), according to the surgical method used to prevent premature contact during BSSO (Fig 8). The sex and age distribution of the patients is shown in Table 2. The sex and age distributions of the groups were statistically similar (Table 2). No significant differences were found in the preoperative type of surgery,

Discussion

The purpose of this study was to measure and compare changes in the postoperative condylar position following BSSO in patients with asymmetry between those treated using PBO and conventional methods.

It is thought that PBO preserves the preoperative position of the condyle better than BSSO in patients with asymmetry. Changes in the condylar position with the 2 different techniques were evaluated prospectively using CBCT, and the effects of these changes on the TMJ were investigated. The authors

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Conflict of Interest Disclosures: None of the authors have any relevant financial relationship(s) with a commercial interest.

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