The Application Of Intelligent Algorithm In Designing Mandibular Angle Osteotomy Templates

Objectives 1.To propose criteria for symmetry,effectiveness,safety evaluation and specifications of individualized mandibular angle osteotomy templates(referred to as "templates ")by analyzing the clinically superior templates measurements and the mandible morphology measurements before and after surgery.2.To establish an intelligent algorithm for designing templates,and compare the templates designed by intelligent algorithm with the templates designed by doctors to evaluate the feasibility of the intelligent algorithm.Methods 1.Collect 1056 patients’ data who underwent mandibular angle osteotomy with templates in the Department of Plastic and Reconstructive Surgery from 2005 to 2018,and establish a database.Screen out 164 patients with complete medical records and good postoperative cosmetic results for retrospective study.Three-dimensional software was used to measure the changes of mandibular morphology before and after surgery,as well as the length,width,height,limit height of templates.The reference standards for designing templates were summarized from the measurements.2.Using the deep learning framework Point Net for point cloud segmentation,ant colony learning and genetic algorithm fusion algorithm for curve fitting,and established the intelligent algorithm for designing templates.987 patient data were screened out from the database and randomly divided into training sets,validation sets and test sets.The training sets and the validation sets were validated and adjusted by the intermediate or senior titled surgeon and then applied to training and optimizing the algorithm.Perform functional test on the well-trained intelligent algorithms.The compliance rate of symmetry,effectiveness and safety between the resident and algorithm designed templates were evaluated.The time consumed for designing was also compared.Results 1.The postoperative absolute value of height difference between bilateral ramus was 1.97±1.58 mm,the excised bone volume was 4.24±1.25 cm3,and the shortest distance from the osteotomy plane to the mandibular canal was 7.52±1.43 mm.The length,width and height of the template were 52.57±2.08 mm,18.17±1.69 mm and 12.91±1.60 mm,respectively.The height of ramus limits was 7.87±1.18 mm,and of the body limits was 8.19±1.16 mm.2.The symmetry compliance rates of doctor and intelligent algorithm designed templates were 87.84% and 83.78%,respectively,the discrepancy was evaluated by non-inferiority tests and P>0.05.There were no significant difference in the effectiveness compliance rate,safety compliance rate,and specification compliance rate between the two groups(P>0.05).The time spent on designing one template was 1685±274 seconds(about 28 minutes)for doctors,and only 8±2 seconds for the intelligent algorithm.Conclusion 1.This study proposes criteria for symmetry,effectiveness,safety evaluation and specifications of templates,and provides an evaluation method for templates designing.2.The intelligent algorithm established in this study can improve the efficiency of designing templates under the premise of ensuring symmetry,safety and effectiveness of osteotomy.