Proximal Segment RotationInferior Border Osteotomy Without Proximal Segment Rotation
Proximal Segment Rotation: During bimaxillary orthognathic surgery, after bilateral sagittal split osteotomy (BSSO), the proximal mandibular segment is rotated to achieve alignment of the inferior border of the proximal and distal mandibular segments before rigid fixation.
Inferior Border Osteotomy Without Proximal Segment Rotation: During bimaxillary orthognathic surgery, after bilateral sagittal split osteotomy (BSSO), the proximal mandibular segment is maintained in its preoperative position. Alignment of the mandibular inferior border is achieved by performing an additional osteotomy at the inferior border of the proximal segment without rotating the proximal segment before rigid fixation.
Study summary
This study aims to evaluate postoperative condylar remodeling in patients undergoing bimaxillary orthognathic surgery by comparing two different proximal segment positioning techniques used during mandibular osteotomy. Condylar remodeling will be assessed using preoperative, immediate postoperative, and 6-month postoperative computed tomography (CT) scans together with clinical findings.
Eligibility
Sex
ALL
Min age
18 Years
Max age
65 Years
Healthy volunteers
Accepted
Inclusion Criteria:
1. Patients with skeletal Class III dentofacial deformity scheduled to undergo bimaxillary orthognathic surgery.
2. Age between 18 and 65 years.
3. Patients who have completed preoperative orthodontic treatment.
4. Patients in whom the mandibular distal segment demonstrates a maximum counterclockwise rotation of 4° after bilateral sagittal split osteotomy (BSSO) when positioned in the final planned occlusion.
Exclusion Criteria:
1. History of temporomandibular joint surgery, orthognathic surgery, or tumor resection.
2. Presence of facial asymmetry.
3. Patients with cleft lip and/or palate, craniofacial syndromes, or a history of maxillofacial trauma.
4. Patients in whom the mandibular distal segment requires more than 4° of counterclockwise rotation after BSSO to achieve the final planned position, as the amount of inferior border (basal) resection required would exceed the clinically acceptable limit.
Primary outcome measure(s)
Three-dimensional condylar axis angular changes — From enrollment to the end of treatment at 6 months Changes in condylar axis orientation will be assessed using computed tomography (CT) by measuring the condylar axis angle in the axial, coronal, and sagittal planes relative to standardized reference planes. In the axial plane, the angle between the condylar axis and the midsagittal reference plane (MSR) will be measured. In the coronal and sagittal planes, the angle between the condylar axis and the Frankfort Horizontal Plane (FHP) will be measured. Preoperative, immediate postoperative, and 6-month postoperative measurements will be compared to evaluate postoperative condylar remodeling and positional changes.
This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
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