Effect of Proximal Segment Positioning on Postoperative Condylar Remodeling in Bimaxillary Orthognathic Surgery

NCT06897787 | Enrolling By Invitation

• 1 other identifier: 07.03.2025-E.185561
• Study Type: interventional
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

Bimaxillary orthognathic surgery is a surgical procedure that involves simultaneous corrections to both the maxilla (upper jaw) and mandible (lower jaw). This surgery is performed to correct facial and jaw deformities, improve occlusion, and enhance facial symmetry. The need for orthognathic surgery typically arises in cases where there is a significant discrepancy between the upper and lower jaws or severe malocclusion. In bimaxillary orthognathic surgery, following mandibular osteotomies, the lower jaw is divided into two segments: the distal segment, which contains the teeth, and the proximal segment, which includes the condylar head. While the distal segment is positioned according to the ideal occlusion planned in collaboration with orthodontists using digital design, the management of the proximal segment varies among surgeons. Some surgeons leave the proximal segment in its original position without mobilization, whereas others reposition it through rotational movements. This study aims to evaluate condylar remodeling by comparing these two surgical approaches in patients divided into two groups, assessing how each technique affects postoperative outcomes.

Conditions

Dentofacial Deformities; Dentofacial Anomalies [Including Malocclusion] and Other Disorders of Jaw (M26-M27)

Keywords

mandibular condyle; orthognathic surgery; manuel condyle positioning

Outcome Measures

Primary Outcomes (1)

• mandibular condyle position superimposition

  During bimaxillary orthognathic surgery, proximal segment positioning devices will be used in both groups to ensure that the condylar position remains at the location determined during virtual surgical planning. These devices will be custom-designed for each patient by the researchers using the virtual surgical planning software and printed using an in-house 3D printer. These positioning devices will maintain the condyle in its initial position during mandibular fixation. Postoperative DICOM data obtained from computed tomography images will be used to superimpose the condylar positions, and the amount of displacement in three planes (x, y, z) will be measured in millimeters (mm). Additionally, condylar volume changes will be calculated in cubic centimeters (cm³) using the superimposition method, and differences between the groups will be evaluated.

  2 year

Study Arms (2)

group 1: Manuel positioning group

ACTIVE COMPARATOR

This is the group in which leveling between the lower border of the proximal segment and the mandibular base is achieved through proximal segment rotation after mandibular osteotomies.

Procedure: manuel positioning group

group 2: mandibular basis osteotomy

EXPERIMENTAL

This is the group in which the proximal segment is left in its preoperative position, and leveling of the mandibular base is achieved by performing an osteotomy on the lower border of the proximal segment.

Procedure: mandibular basis osteotomy

Interventions

manuel positioning group PROCEDURE

As Prof. Reyneke does, mandibular base and proximal segment leveling are performed first, followed by fixation.

group 1: Manuel positioning group

mandibular basis osteotomy PROCEDURE

After the mandibular sagittal split, secure the proximal segment in its preoperative position and remove the bone piece for leveling. After that, fixation is performed.

group 2: mandibular basis osteotomy

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Patients planned to undergo bimaxillary orthognathic surgery with Class III skeletal deformity
• Patients aged 18-65
• Patients who have undergone preoperative orthodontic treatment
• Patients who, after mandibular distal segment sagittal split osteotomy, exhibit a maximum of 4 degrees of counterclockwise rotation when brought to the final position

You may not qualify if:

• Patients with a history of joint surgery, orthognathic surgery, or tumor resection
• Patients with facial asymmetry
• Patients with cleft lip and palate syndrome, craniofacial syndrome, or trauma
• Patients who, after mandibular distal segment sagittal split osteotomy, exhibit more than 4 degrees of counterclockwise rotation when brought to the final position (as the amount of base resection required in this case would exceed feasible limits).

Sponsors & Collaborators

• Bezmialem Vakif University: lead

Study Sites (1)

Bezmialem Vakıf Universty

Istanbul, Fatih, 34093, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Dentofacial Deformities

Condition Hierarchy (Ancestors)

Maxillofacial Abnormalities; Craniofacial Abnormalities; Musculoskeletal Abnormalities; Musculoskeletal Diseases; Stomatognathic System Abnormalities; Stomatognathic Diseases; Congenital Abnormalities; Congenital, Hereditary, and Neonatal Diseases and Abnormalities

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 17, 2025
• First Posted: March 27, 2025
• Study Start: March 30, 2025
• Primary Completion (Estimated): March 1, 2027
• Study Completion (Estimated): April 30, 2027
• Last Updated: June 24, 2025

Record last verified: 2025-06

Locations

TU (1)