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A Postoperative Evaluation Guideline for Computer-Assisted Reconstruction of the Mandible
Published on: January 28, 2020
Short-term changes of condylar position after sagittal split osteotomy for mandibular advancement
M E Alder1, S T Deahl, S R Matteson
1Department of Dental Diagnostic Science, The University of Texas Health Science Center at San Antonio, 78284-7919, USA.
Summary
Mandibular advancement surgery with rigid fixation causes condylar position changes in all planes. Postoperatively, condyles most commonly shift laterally, with increased angle, and are positioned superiorly and posteriorly in the fossa.
Area of Science:
- Orthognathic surgery
- Maxillofacial reconstruction
- Surgical anatomy
Background:
- Mandibular advancement surgery is a common procedure for treating skeletal discrepancies.
- Rigid fixation using screws is a standard method for stabilizing the mandible post-surgery.
- Understanding postoperative condylar position is crucial for predicting long-term outcomes.
Purpose of the Study:
- To quantify changes in condylar position in three dimensions (X, Y, and Z planes) after mandibular advancement surgery.
- To evaluate the impact of rigid fixation on condylar position.
- To correlate condylar position changes with surgical outcomes.
Main Methods:
- A cohort of 21 patients undergoing mandibular advancement with rigid fixation was studied.
- Computed tomography (CT) scans were acquired 1 week preoperatively and 8 weeks postoperatively.
- Two-dimensional reconstructions from CT data were used to measure condylar position and orientation.
Main Results:
- Condylar position changes were observed in all measured planes (lateral/medial displacement, angular changes, superior/inferior rotation, anterior/posterior displacement).
- The most frequent postoperative position involved lateral displacement (55%), increased condylar angle (60%), inferior rotation of the proximal segment (61%), superior displacement (60%), and posterior displacement (67%).
- Significant ranges of displacement and rotation were noted, indicating variability in individual responses.
Conclusions:
- Mandibular advancement surgery with rigid fixation leads to predictable, yet variable, changes in condylar position across all anatomical planes.
- Postoperative condylar positioning tends to be more lateral, with increased angular changes, and superior and posterior placement within the glenoid fossa.
- These findings highlight the importance of considering three-dimensional condylar behavior in surgical planning and outcome assessment.
