Making Robots Mill Bone More Like Human Surgeons: Using Bone Density and Anatomic Information to Mill Safely and...

Area of Science:

• Robotics
• Biomedical Engineering
• Surgical Technology

Background:

• Traditional robotic bone milling, akin to industrial Computer Numeric Controlled (CNC) machining, lacks the adaptability of human surgeons.
• Surgeons dynamically adjust milling parameters (speed, depth, angle) based on bone porosity and proximity to critical structures like nerves and blood vessels.
• Existing robotic systems often employ uniform milling strategies, potentially leading to suboptimal efficiency and increased risk in complex anatomical regions.

Purpose of the Study:

• To develop a robotic bone milling strategy that emulates a surgeon's adaptive approach.
• To create patient-specific milling plans by integrating image-based bone density and vital anatomy segmentation.
• To optimize milling velocity and tool incidence angles for spherical cutting burrs, particularly for variable density bone like the temporal bone.

Main Methods:

• Utilized image-based bone density estimations and segmentations of vital anatomy to guide robotic milling.
• Developed patient-specific surgical plans that optimize milling velocity and incidence angles for spherical burrs.
• Compared the novel adaptive robotic milling approach against a conventional CNC-type path on temporal bone phantoms.

Main Results:

• The adaptive robotic milling strategy significantly reduced forces near vital anatomy, with mean forces decreased by 63% and peak forces by 50%.
• The optimized milling approach achieved faster milling in non-critical areas, thereby reducing overall procedure time.
• Experimental validation on temporal bone phantoms demonstrated the efficacy and safety of the surgeon-mimicking robotic milling technique.

Conclusions:

• Image-based planning enables robots to perform bone milling more adaptively, similar to surgeons.
• This approach enhances safety by reducing forces near critical anatomical structures.
• The developed method improves milling efficiency in variable density bone without extending surgical duration.