PhD Thesis Proposal: Haley Stoner

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"MaRIC RoC12: MRI Compatible Robot for C1-C2 Fixation"

Abstract

C2 fractures are breaks in the second vertebrae of the cervical spine. These fractures can be treated through surgical (C1-C2 fixation) or nonsurgical intervention (collar). Even though surgical intervention is seldom enacted, this treatment type leads to higher fusion rates and faster patient recovery times. C2 fractures are located in a high critical density area for surgical treatment due to the close proximity of the vertebral artery, cervical nerves, and spinal column. C1-C2 fixation standard of care employs intraoperative fluoroscopy or CT (computed tomography) to guide surgeons while they manually join the C1-C2 vertebrae with pedicle screws. This standard of care exposes staff and patients to radiation and provides an incomplete imaging modality since the surgical tools induce artifacts during imaging and the imaging modality is specialized towards hard tissue imaging (bone) instead of soft tissue imaging (critical structures). Alternative approaches involve robotic platforms that provide guides for the surgeons during pedicle placement and have proven to increase placement accuracy; however, these pedicle screw placements are limited to the thoracic or lumbar spine as the C1-C2 fixation standard of care deficits also impact this approach.
 
To overcome the standard of care limitations, an MRI (magnetic resonance imaging) compatible robot for C1-C2 fixation will be fabricated. With MRI being the preferred soft tissue imaging modality, a robotic platform would be able to provide increased placement accuracy with close to real time intraoperative guidance without radiation or the need for tool removal. The development has been divided into three methods: drill, tool, and MRI. Drill methods confront the end effector development with piezoelectric motors compared to a standard of care orthopedic drill, Stryker System 6. Bone drilling is the backbone of C1-C2 fixation and OTS (off the shelf) solutions do not exist. Tool methods undertake the drill bit and implant requirements to meet MRI compatibility and strength for C1-C2 fixation. Stainless steel drill bits are the standard of care but exhibit detrimental artifacts during surgical procedures over the ROSI (region of surgical interest). Ultimately, MRI methods implements the drill and tooling on an MRI robotic platform for porcine cadaver C1-C2 fixation evaluation.

Thesis Committee

• Keith Paulsen (Chair)
• Sohail Mirza
• John Weaver
• Kevin Clearly (External)

Contact

For more information, contact Thayer Registrar at thayer.registrar@dartmouth.edu.