Parametrizing the genioplasty: a biomechanical virtual study on soft tissue behavior

Area of Science:

• Oral and Maxillofacial Surgery
• Orthognathic Surgery
• Biomechanical Simulation

Background:

• Sliding genioplasty corrects chin deformities by repositioning a bone segment after osteotomy.
• Understanding the impact of surgical variables on soft tissue outcomes is crucial for predictable results.

Purpose of the Study:

• To investigate the influence of surgical parameters, specifically bony segment movement and osteotomy design, on postoperative soft tissue changes in sliding genioplasty.
• To evaluate the sensitivity of soft tissue alterations to variations in horizontal and vertical displacement, and rotation of the repositioned bone segment.

Main Methods:

• Retrospective analysis of seven patients with cone beam computed tomography (CBCT) data.
• Creation of 3D bone and soft tissue models, replicating surgical cuts based on postoperative scans.
• Finite element analysis (FEA) using ANSYS software to simulate the effects of varying surgical parameters on soft tissue displacement at key craniometric landmarks.

Main Results:

• Soft tissue changes in the lower third of the face were significantly influenced by the horizontal and vertical displacement, as well as the rotation of the bony segment.
• The specific design of the osteotomy did not yield statistically significant variations in the soft tissue response.

Conclusions:

• Surgical planning for sliding genioplasty should prioritize the precise control of bony segment movement (translation and rotation).
• The osteotomy design appears to be a less critical factor in determining soft tissue outcomes compared to segment repositioning.