Patient-Specific Bone Milling Paths for Precise Resection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional milling path generation techniques in robotic surgical systems are inefficient, leading to increased path length and milling time, and often result in suboptimal resection volumes that remove more material than necessary, causing "air-cutting" and potential collisions with adjacent tissues.
Innovation Solution
A computer-implemented method for generating a milling path that involves obtaining a virtual model of the bone, defining a resection volume with an offset boundary, and generating section paths and transition segments to create a milling path that is optimized to remove only the necessary material, constrained to the hard tissue, and adaptable for intra-operative modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional milling path generation techniques are used, then the milling path can be generated to remove the resection volume, but the overall path length and milling time are increased
Solution Approach 1:
The milling path is segmented into multiple sections, each optimized for specific regions of the resection volume. The path is divided into entry segments, main milling segments, and exit segments, allowing each portion to be optimized independently for both precision and efficiency.
Solution Approach 2:
The milling path employs dynamic adjustments in tool orientation, speed, and feed rate along different segments of the path. The system adapts milling parameters in real-time based on the local geometry and material removal requirements, optimizing both precision and productivity.
2Reliability
If implant-specific worst case milling paths are designed, then the path accounts for all possible implant placements, but more material is removed than needed and air-cutting occurs
Solution Approach 1:
The milling path applies different removal strategies to different regions of the bone. Critical areas near the implant site receive precise, minimal removal, while less critical areas use more aggressive removal. This localized approach maintains reliability for implant placement while minimizing unnecessary material loss.
Solution Approach 2:
The system dynamically changes milling parameters such as depth of cut, feed rate, and tool orientation based on the local anatomical context and implant requirements. This allows the path to adapt to different implant placements without always removing the maximum possible material.
3Object-affected harmful factors
If the milling path is constrained to hard tissue boundaries, then surrounding soft tissue is protected, but the path planning becomes more complex
Solution Approach 1:
The system performs preliminary identification and mapping of hard tissue boundaries before generating the milling path. Virtual boundaries and safety zones are pre-defined based on anatomical landmarks and imaging data, simplifying the subsequent path planning while ensuring soft tissue protection.
4Force
If the milling path is generated pre-operatively, then the resection volume can be planned, but intra-operative modifications to implant placement cannot be accommodated
Solution Approach 1:
The milling path system transitions from static pre-operative planning to dynamic intra-operative generation. The path is computed in real-time based on actual anatomical measurements and surgeon decisions made during surgery, allowing full adaptability while maintaining planning capability.
Data Source
AI summary
Generating a milling path to enable a tool to remove material from bone. An allowed volume is intersected with a virtual bone model. An offset boundary is spaced inward from the allowed volume. Intersection between the allowed volume and the virtual bone model defines a resection volume. An outer portion of the resection volume is defined between the allowed volume and offset boundary. An inner portion of the resection volume is defined within the offset boundary. Section planes are defined to successively intersect the resection volume. Section paths are bounded within each section plane and are defined relative to the resection volume. One or more sections plane includes a section path with a path segment enabling the tool to remove only the outer portion of the resection volume. Transition segments connect section paths of successive section planes. The section paths and transition segments are combined to generate the milling path.