GP1d - Evaluation of Preformed Orbital Implants Using 3D Segmentation

Presenting Author(s)

• 

  Braedon F. Gunn

  D4 Student
  Texas A&M College of Dentistry

Co-Author(s)

• 

  Andrew M. Read-Fuller, DDS, MD, FACD, FACS

  Clinical Associate Professor, Residency Program Director
  Texas A&M College of Dentistry
  Dallas, Texas
• 

  Likith V. Reddy, DDS, MD

  Professor and Head, Oral and Maxillofacial Surgery
  Texas A&M University School of Dentistry and Baylor University Medical Center
  Dallas, Texas
• CZ

  Chi Zhang, PhD

  Instructional Assistant Professor
  Department of Biomedical Sciences, Texas A&M College of Dentistry
  Dallas, Texas
• MK

  Matthew J. Kesterke, PhD, MA

  Assistant Professor
  Department of Orthodontics, Texas A&M College of Dentistry
  Dallas, Texas

Abstract:

Objectives: This study aims to compare preformed stock plates for orbital fracture reconstruction by developing standard measurements to assess their fit. Stock plates are cost-effective but require intraoperative adjustments, while custom plates offer better fit and outcomes but are more expensive and time-consuming. Research shows that patient-specific implants improve orbital volume reconstruction and reduce complications (Timoshchuk, 2022), and that patient-specific implants lead to better outcomes than manual bending (Raisian et al, 2017). However, due to cost and time constraints, stock plates are more commonly used. This study seeks to identify areas where stock plates fit well and poorly across various fractures, providing a basis for improving design. By evaluating the fit of various plates, this study hopes to propose design modifications to improve stock plates’ adaptability and reduce intraoperative adjustments. Ultimately, this research aims to enhance surgical outcomes and streamline decision-making in orbital fracture repair.

Methods: 3D models of fractured orbits from seven patients were segmented using 3D slicer. STL files of plates were obtained from a primary manufacturer (both “small” and “large” types). We created a 3D Slicer module to semi-automatically register the plate to the fracture site (Figure 1). Real-time collision detection and markers were used for assisting interactive plate adjustment for optimal fit. Plate fitness is quantified by measuring the deviation of the plate from the reconstructed orbit using a heatmap (Figure 2). Additionally, the deviation of the plate’s anterior and lateral margins from the surface of the reconstructed orbit is assessed by sampling points along the underside of the plate, which are then projected onto the reconstructed orbit (Figure 2). The distances between the two surfaces are subsequently calculated. Statistical analysis was conducted using ANOVA.

Results: Out of the 7 specimens evaluated, the “large” plate was a better fit for 3 specimens, while the “small” plate was more suitable for another 3. For one specimen, neither plate was a good fit for the fracture type. In a specimen where the “large” plate was recommended, it was observed that the deviation from the anterior/lateral edges of the plate to the reconstructed orbit was smaller than it was with the “small” plate (Figure 3). Additionally, when analyzing the heatmap data, it was found that the overall plate deviation was less with the “large” plate compared to the “small” plate (Figure 3).

Conclusions: Results suggest that preformed plates may not adequately adapt to each patient’s orbit, thus need considerable modification. We will continue to evaluate preformed plate fitness across populations. We are also in the process of developing our customized 3D Slicer module into a robust open-source software for virtual orbital surgery planning and simulation.

References:
Raisian S, Fallahi HR, Khiabani KS, Heidarizadeh M, Azdoo S. Customized Titanium Mesh Based on the 3D Printed Model vs Manual Intraoperative Bending of Titanium Mesh for Reconstructing of Orbital Bone Fracture: A Randomized Clinical Trial. Rev Recent Clin Trials. 2017;12(3):154-158. doi: 10.2174/1574887112666170821165206. PMID: 28828975.

Timoshchuk MA, Murnan EJ, Chapple AG, Christensen BJ. Do Patient-Specific Implants Decrease Complications and Increase Orbital Volume Reconstruction Accuracy in Primary Orbital Fracture Reconstruction? J Oral Maxillofac Surg. 2022 Apr;80(4):669-675. doi: 10.1016/j.joms.2021.12.006. Epub 2021 Dec 21. PMID: 35007501.
Figure 1 Figure 2 Figure 3