Piezosurgery Versus Conventional Techniques in Orthognathic Surgery

The goal of this randomized double-blinded controlled clinical trial is to determine whether piezosurgery can reduce complications and improve outcomes compared to conventional osteotomy techniques in patients undergoing bilateral sagittal split osteotomy (BSSO), with or without concurrent Le Fort I osteotomy (bimaxillary surgery).

The main questions this study aims to answer are:

* Does piezosurgery reduce inferior alveolar nerve impairment following BSSO compared to conventional techniques? * Does piezosurgery affect surgical duration, intraoperative blood loss, rates of bad splits, postoperative infections, costs, and environmental sustainability compared to conventional techniques?

Researchers will compare BSSO performed with piezosurgery versus BSSO performed with conventional oscillating saw and burr techniques to see if piezosurgery leads to better sensory outcomes, reduced morbidity, and improved cost-effectiveness and sustainability.

Participants will be:

* Dutch or English-speaking adults aged 18-65 scheduled for BSSO or BIMAX surgery at Erasmus Medical Centre (Rotterdam) or St. Anna Hospital (Geldrop, Netherlands). * Exclusions include bone healing disorders, coagulation issues, facial trauma history, smoking, craniofacial anomalies, and planned simultaneous genioplasty.

Participants will:

* Undergo preoperative assessment of inferior alveolar nerve function (two-point discrimination test, validated questionnaire). * Be randomized into:

* Intervention group: BSSO performed entirely using piezosurgery. * Control group: BSSO performed with conventional burr and saw techniques. * Have their surgery performed by experienced maxillofacial surgeons following standardized protocols. * Have operative time and blood loss recorded during surgery. * Be followed up at 1 week, 3 months, 6 months, and 1 year for nerve function, sensory recovery, and infection assessment. * Complete postoperative questionnaires on sensory changes at 3 months and 1 year. * Have surgical outcomes evaluated by blinded examiners. * Contribute to a life cycle cost analysis (LCC) and life cycle assessment (LCA) comparing equipment cost, maintenance, energy use, waste generation, and environmental impact between techniques.