Feasibility of Generatively Designed Patient-Specific Implants for Orthognathic Surgery: An In Silico Comparative Study.

INTRODUCTION AND AIMS: To investigate whether generatively designed (GD) patient-specific implants are equivalent to manually designed (MD) PSIs for orthognathic surgery in the in silico setting.

METHODS

Twelve pairs of GD and MD fixation plates for Le Fort I osteotomy and genioplasty were compared regarding plate-bone shape fit, biomechanical performance, plate size, and design time. Shape fit was measured as the signed distance from the plate vertices to the underlying bone surface to estimate potential surgical accuracy. Biomechanical performance (von Mises stress and deformation) was analysed using finite element analysis. Plate size was quantified by both surface area and volume. Hands-on design time was recorded for GD by stage, and historical data on MD time were referenced for context.

RESULTS

GD plates demonstrated better shape fit, with a lower mean plate-bone distance (0.95 ± 0.17 mm) than MD plates (1.12 ± 0.28 mm; P < .05). The maximum von Mises stresses of both plates were within the ultimate tensile strength of titanium (345 MPa), and the greatest deformations were within 0.55 mm, demonstrating sufficient biomechanical stability. GD plates reduced the surface area by 16% (P < .001) and volume by 18% (P < .05) compared to MD plates. Average hands-on design time for GD plates was 94.3 ± 14.2 minutes for Le Fort I and 45.0 ± 7.3 minutes for genioplasty, which was substantially shorter than MD time reported in prior in-house workflows.

CONCLUSIONS

GD fixation plates demonstrated improved shape fit, adequate mechanical strength, smaller size, and reduced design time compared with MD plates.

CLINICAL RELEVANCE: The objective analysis of GD fixation plates in silico is important for justifying further application in clinical trials.