Bone Model Registration Using Adaptive Soft Tissue Thickness
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Solution Overview
Problem
Existing bone model registration methods in orthopaedic surgery often require piercing or contacting soft tissue to register a prosthetic joint, leading to increased surgical time and variability, and may not accurately account for local soft tissue variations.
Innovation Solution
A method and system that registers a three-dimensional bone model by capturing point positions on the patient's anatomy, estimating soft tissue thickness, and optimizing the registration process to align the model with the surgical coordinate system without directly contacting the bone, using a registration tool and camera array to track the pointer on soft tissue surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing bone model registration methods contact or pierce soft tissue to register prosthetic joint, then registration can be performed, but surgical time increases and variability increases
Solution Approach 1:
The patent introduces an intermediary registration process that uses soft tissue thickness measurements as a mediator between the external anatomical surface and the underlying bone model. By measuring soft tissue thickness at multiple points and using these measurements to compensate for the gap between the registered model and actual bone position, the system achieves accurate registration without requiring direct contact or piercing of the soft tissue, thereby reducing surgical time and variability.
2Measurement precision
If existing bone model registration methods contact or pierce soft tissue, then registration can be performed, but surgical variability increases
Solution Approach 1:
The soft tissue thickness measurements serve as an intermediary parameter that standardizes the registration process across different patients and surgical conditions. By using these measurements to systematically compensate for soft tissue variations, the method reduces surgical variability and improves reliability while maintaining registration accuracy.
Solution Approach 2:
The patent changes the registration approach by incorporating soft tissue thickness as a compensating parameter. Instead of directly registering to the bone surface through tissue contact, the system adjusts the registration by the measured soft tissue thickness values, transforming the registration problem into one that accounts for variable soft tissue parameters, thereby reducing variability.
3Ease of manufacture
If existing registration methods do not account for soft tissue variations, then surgical procedure is simpler, but registration accuracy deteriorates
Solution Approach 1:
The patent maintains surgical simplicity by using non-invasive soft tissue thickness measurements as intermediaries. The measurement process itself is simple and does not require complex procedures, but the data obtained serves as a crucial mediator to improve registration accuracy by compensating for soft tissue variations between the external surface and the bone model.
Data Source
AI summary
Systems and methods for planning and assisting orthopaedic surgical procedures include a computing device and a robotic surgical device. The computing device defines a surgical coordinate system relative to a bone of a patient and captures a plurality of point positions in the surgical coordinate system. The plurality of point positions includes a first point position representing a location on a soft tissue surface covering a portion of the patient's bone. The computing device identifies an estimated soft tissue thickness value for each of the plurality of point positions and registers a three-dimensional model of the patient's bone in the surgical coordinate system based on the plurality of point positions and the estimated soft tissue thickness values. The computer system may control the robotic surgical device according to the registered bone model.