UBC Theses and Dissertations

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UBC Theses and Dissertations

An image-guided platform for on-the-fly mandibular reconstruction surgery Stewart, Molly Murray


Mandible reconstruction surgery requires a surgeon to remove a section of the mandible bone affected by a tumor and recreate the curved contour of the jaw using a donor bone since the mandible is fundamental in helping the patient to eat, talk and breathe. The most common donor bone used is the fibula, and the surgery requires small fibula segments of a specific length and cut angle to be created which are then aligned to one another to form the desired curve. Currently surgeons During this lead time the tumor can grow, and pre-printed guides cannot be changed during surgery to accommodate this. Our research has addressed these issues through the development of a fully image-guided mandible reconstruction workflow. The scope of this thesis was to develop the software required to integrate image guidance into this procedure, investigate methods to guide the fibula cuts, and perform proof-of-concept testing on the fully-integrated system. A user study on the fibular cutting process highlighted that using an image-guided cutting guide would be the most feasible method for guiding the fibula cuts in a surgical environment. This method was able to replicate the planned fibula cuts with an average deviation of -0.68±2.66 mm in segment length and 3.68±2.59 ̊ in cut angle. Bench testing of the integrated system's workflow demonstrated that we could successfully perform an on-the-fly simulation of the surgery without requiring any pre-surgical planning as the VSP is generated during the surgery and can be changed as required throughout. Proof-of-concept testing performed on five cadaver specimens further demonstrated successful execution of the workflow in a more realistic surgical setting. These tests resulted in accuracy metrics that are comparable to existing state-of-the-art systems using 3D-printed cutting guides such as an average Dice score of 0.81 and Hausdorff distance of 0.94 mm when compared to the VSP. By utilizing image guidance during all stages of the surgical workflow, including to guide the fibula cuts, this system demonstrates that an on-the-fly surgical workflow is possible, which, once transferred to the operating room, would eliminate the lead time and inflexibility of the physical cutting guides.

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