(29) Point-of-Care Virtual Surgical Planning for Orthognathic Surgery: Determining Accuracy of In-House vs. Outsourced Planning

Abstract: Virtual surgical planning (VSP) has become the standard for orthognathic surgery and is largely performed by outsourced (OS) companies. Potential downsides of OS VSP include increased time, cost, and resources. Progress in computer-aided design (CAD) software may enable the implementation of in-house (IH) or point-of-care (PoC) VSP. While it may provide advantages including reduced costs and time, PoC VSP has never been validated in the literature. Currently, no universally accepted approach exists for evaluating accuracy of VSP. This study aims to propose a standardized method for analysis of VSP accuracy and demonstrate equivalence between PoC VSP and OS VSP.This is an in vitro retrospective study of orthognathic surgery cases performed by Virginia Commonwealth University Department of Oral and Maxillofacial Surgery. Exclusion criteria included cases with segmental Le Fort surgery, genioplasty, or patient-specific implants. OS VSP standard tessellation language (STL) files were created on Materialise PROPLAN CMF, and IH VSP STL files were made utilizing Materialise Mimics Enlight CMF. Postoperative (PO) cone-beam computed tomography (CBCT) Digital Imaging and Communications in Medicine (DICOM) and preoperative intraoral (IO) scans were collected for each patient. The analysis was divided into an anatomic (1) and occlusal assessment (2). For the anatomic analysis (1), DICOM was segmented on Materialise Mimics and exported as a stereolithographic file (STL). Standardized segmentation protocol was developed to include major cephalometric landmarks involved in orthognathic surgery while excluding dentition and irrelevant anatomy. Using the same protocol, IH and OS VSP STL files were formatted on Meshmixer. For the occlusal analysis (2), IO scans were imported into the PO DICOM on RealGuide (RealGUIDE, 3DIEMME, Milan, Italy), and were exported as a unionized STL. This file, along with IH and OS VSP, was edited on Meshmixer to exclusively include the dentition. All anatomic and occlusal STL files were uploaded into Materialise 3-Matic, and IH and OS files were superimposed onto the PO file. Whole-surface analysis via root mean square (RMS) value was calculated.Statistical analysis was performed with SASv9.4. Descriptive statistics was used to reflect RMS values and averages for each specific group. A 2 one-sided t-tests (TOST) approach was used at 0.05 level to determine the equivalence bounds between the results of these groups.A total of 10 subjects were enrolled in the study. Data collection is still undergoing. However, the average RMS for the groups so far are: 0.4155 mm/1.696mm (anatomic IH/PO - mandible/maxilla), 0.305 mm/2.474 mm (anatomic OS/PO - mandible/maxilla), 0.3022 mm (occlusal IH/PO), 0.3151 mm (occlusal OS/PO). The average difference between occlusal IH and OS groups was -0.0129, with OS tending to have a higher RMS. Results from the TOST method deemed that the two methods were equivalent within +/-0.2 based on a 90% equivalence interval of -0.1077, 0.0819 (P-value = .0094). Equivalence analysis for the anatomic OS/PO is pending further data collection. Based on preliminary results, IH and OS VSP for orthognathic surgery both demonstrated equivalence when measured to PO CBCT. We propose a standardized VSP analysis protocol using whole surface analysis and measuring occlusal and anatomic positions separately to achieve increased accuracy compared to the literature.[2] This study offers initial evidence for PoC VSP. However, additional quality assurance protocols for PoC VSP are essential. More studies are needed to test PoC applications in orthognathic surgery, including its clinical applications, time, and cost savings. References 1. Alkhayer A, Piffkó J, Lippold C, Segatto E. Accuracy of virtual planning in orthognathic surgery: a systematic review. Head Face Med. 2020;16(34). https://doi.org/10.1186/s13005-020-00250-22. Tondin GM, Leal M de OCD, Costa ST, Grillo R, Jodas CRP, Teixeira RG. Evaluation of the accuracy of virtual planning in bimaxillary orthognathic surgery: a systematic review. Br J Oral Maxillofac Surg. 2022;60(4):412-421. doi:10.1016/j.bjoms.2021.09.010

Figure 1