NA-MIC Project Weeks

Back to Projects List

Evaluate the fit of preformed plates in orbital surgery

Key Investigators

• Chi Zhang (Texas A&M College of Dentistry)
• Andrew Read-Fuller (Texas A&M College of Dentistry)

Project Description

Orbital fracture repair commonly used preformed/contoured plates. ProprietaryVirtual Surgical Planning (VSP) soft focused on customized plate manufacture and placement guidance but does not allow comparing the fit of plates across vendors. The goal of this project is to allow surgeons to interactively try different ways of placement or different plates and compare the fit to find the more suitable implant. I created a customized module plateRegistration

Current procedures:

1. Alignment using the Interaction Transform Handle: rotate around the “posterior stop” landmark until the plate sits just above the. Real-time heatmap using Probe Model with Volume module and VTK collision detector can mark intersections to aid plate position adjustment.

1. Reconstructing the fractured orbit using the mirror of the contralateral side: use DentalSegmentator to segment the bone. Use point cloud-based rigid registration plus deformable registration to align the mirrored orbit to the fractured one.

1. Measuring fit by projecting fiducial points on plate edges to the reconstructed orbit. Fit is based on overall distances. Overall distance map can also be used. These distances can also be used to highlight largest deviation.

Objective

The current workflow is tedious. My goal is to simplify the process.

1. Objective A. Design UI to simplify fractured orbit reconstruction step
2. Objective B. Improve fit measurements.
3. Objective C. Segmentation of fractured and intact orbits. Orbital bones are two thin. DentalSegmentator performs well, but sometimes only a boundary between maxillary sinus & orbit is preserved.
4. Objective D. Explore using SlicerSOFA to bend the plate and fit snuggly to the orbit. See project page: https://github.com/NA-MIC/ProjectWeek/issues/1459

Approach and Plan

1. Improve UI design to simplify orbital reconstruction. Testing direct image registration and warping using ANTs in SlicerAntsPy.
2. Create new metrics for measuring the fit of plates, including those less relying on orbital reconstruction.
3. Improve UI design to simplify the overall workflow.
4. Simplify segmentation workflows for thin orbital bones. In some cases, the orbital floor and medial wall are too thin, and only a boundary between the sinus and orbit is visible. I segmented maxillary sinus, expand it, and create a shell to fix the orbit. Perhaps models used in DentalSegmentator or TotalSegmentator can be tuned to depict the boundary between sinus & orbit.

Progress and Next Steps

1. Describe specific steps you have actually done.

Illustrations

Surgical Guidance using MatrixOrbital preformed plates from DePuy (see below for reference).

Transconjunctival approach for retracting orbital tissue. From: https://surgeryreference.aofoundation.org/cmf/pediatric-trauma/midface/orbital-floor/reconstruction

Background and References

Surgical Guidance using MatrixOrbital preformed plates from DePuy Synthesis: https://www.jnjmedtech.com/en-US/product/matrixorbital-preformed-orbital-plates

Orbital floor and wall fracture repair guidance: https://surgeryreference.aofoundation.org/cmf/pediatric-trauma/midface/orbital-floor/reconstruction