Virtual planning and 3D‐printed guides for mandibular reconstruction: Factors impacting accuracy

OBJECTIVES: Examine accuracy and factors impacting accuracy for mandibular reconstruction with virtual surgical planning, 3D printed osteotomy guides and preoperatively bent mandibular reconstruction plate (VSP/3Dprinted‐guide/plate). METHOD: Retrospective review of osseous‐free‐flap mandibular reconstructions with VSP/3Dprinted‐guide/plate between January 2015 and July 2020 at a single academic medical center. Patient demographics, disease, and treatment variables were extracted. Accuracy was assessed by 3D‐model‐overlay with cephalometric and donor‐bone segment length measurements. Multivariate analyses were performed to determine factors impacting cephalometric accuracy. RESULTS: 60 cases met criteria: 41 (68%) cancer, 14 (23%) osteoradionecrosis (ORN), 5 (8%) secondary mandibular reconstruction. Thirteen cases (22%) were Brown class III or IV. Thirty‐nine cases (65%) had ≥2 flap bone segments. Average donor‐bone length was 82 mm (SD: 28). 3D‐model‐overlay accuracy demonstrated minimal deviation between planned and actual reconstruction: intercondylar distance = 2.10 mm (SD: 2.2); intergonial distance = 2.23 mm (SD: 1.9); anterior–posterior distance (APD) = 1.76 mm (SD: 1.5); gonial angle (GA) = 3.11 degrees (SD: 2.4). Mean change in donor‐bone segment length inferiorly was 2.67 mm (SD: 2.6) and superiorly 3.27 mm (SD: 3.2). Higher number of donor‐bone segments was associated with decreased accuracy in GA (p = .023) and longer donor‐bone length was associated with decreased accuracy in APD (p = .031). CONCLUSION: To our knowledge this is the largest series assessing surgical accuracy of VSP/3Dprinted‐guide/plate for osseous‐free‐flap mandibular reconstruction. We demonstrate highly accurate results, with increased number of donor‐bone segments and donor‐bone length associated with decreased accuracy. Our findings further support VSP/3Dprinted‐guide/plate as a reliable and accurate tool for mandibular reconstruction. LEVEL OF EVIDENCE: Level 4.