Maxilla-first patient-specific osteosynthesis vs mandible-first bimaxillary orthognathic surgery using splints: a...

Area of Science:

• Oral and Maxillofacial Surgery
• Orthodontics
• Biomedical Engineering

Background:

• Orthognathic surgery aims to correct jaw discrepancies.
• Patient-specific instrumentation enhances surgical precision.
• Comparing surgical sequencing is crucial for optimizing outcomes.

Purpose of the Study:

• To compare the accuracy of a mandible-first approach versus a maxilla-first approach with patient-specific osteosynthesis (PSO) in bimaxillary orthognathic surgery.
• To evaluate the clinical accuracy and deviations from the surgical plan for each approach.

Main Methods:

• A multi-centre randomized controlled trial involving 88 patients undergoing bimaxillary orthognathic surgery.
• Patients were randomized into two groups: mandible-first with an intermediate splint and maxilla-first with PSO.
• Postoperative accuracy was assessed using cone beam computed tomography (CBCT) and clinical outcome categorization.

Main Results:

• The maxilla-first with PSO group showed significantly lower deviations in anteroposterior translation (1.0 mm vs 1.8 mm) and yaw rotation (0.5° vs 1.0°) compared to the mandible-first group.
• Clinical accuracy was superior in the maxilla-first with PSO group, with 59.5% achieving optimal or good results versus 17.5% in the mandible-first group.
• The maxilla-first with PSO approach demonstrated enhanced precision in achieving planned surgical movements.

Conclusions:

• The maxilla-first approach utilizing patient-specific osteosynthesis fixation provides superior accuracy in bimaxillary orthognathic surgery.
• This method offers significant advantages over the traditional mandible-first approach, particularly in minimizing deviations from the surgical plan.
• The findings support the adoption of the maxilla-first PSO technique for improved surgical outcomes in orthognathic procedures.