Robotic Point-of-Care Manufacturing of Personalized Skeletal Fixation

Conference Abstract: The shape of skeletal fixation hardware is often personalized, most commonly through hand-operated bending tools used at the point-of-care. More and more commonly, a Virtual Surgical Plan (VSP) is conducted on computer and the shape of the reconstructed anatomy is 3D printed. A personalized fixation device is then bent to fit that model. In this case the surgeon’s goal is to fit the fixation device flush to the model at the pre-planned location. However, that process provides the surgeon little help in choosing a device or optimizing (personalizing) it’s anticipated performance. Theoretically, VSP software could facilitate optimization of a fixations device’s location (relative to the patient’s anatomy), material properties, and shape (i.e., external surface shape and internal porosity) relative to it’s intended performance. A focus on performance would be likely to improve patient outcomes. Moreover, a fabrication process that guarantees a fixation plate will have the desired shape and mechanical properties would be beneficial to the patient. To our knowledge current VSP software offers no plan for fabrication, including the hand-operated bending tools that are universally available. Thus it is not unlikely that segments of the fixation plate will undergo unnecessary repeated bending. Those segments will have an increased risk for work hardening. Work hardened locations are at increased risk for failure due to cyclic loading (i.e., fatigue failure). In addition to a model of the reconstruction, VSP software could provide instructions for incremental bending of the fixation device to avoid the need for secondary bending. Moreover, while no commercial device exists, researchers at the NSF-supported Engineering Research Center, HAMMER, are currently working to develop both VSP for fixation device personalized optimization and a robotic fixation bending device currently referred to as the “BendyBot”.