Orthopedic Surgery Guidance with Marker-Free Kinematic Tracking
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Solution Overview
Problem
Current computer-guided surgery systems rely on optical markers or ionizing radiation, which are cumbersome, expensive, and pose health risks, and lack real-time control, constraining surgical staff positioning and increasing procedure time.
Innovation Solution
A system that uses a kinematic chain with sensors to align virtual surgical plans with real-time patient anatomy, eliminating the need for optical markers and ionizing radiation by tracking the surgical tool's position and orientation relative to the patient's bone using 3D imaging and mechanical references.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical markers and tracking arrays are used to track surgical instruments and bones, then positioning accuracy is improved, but device complexity and procedure time increase
Solution Approach 1:
The patent replaces the optical tracking system with a mechanical reference system. Instead of using optical markers and tracking arrays, the invention uses a mechanical reference element rigidly fixed to the bone that is directly coupled to the surgical tool holder through a kinematic chain. This mechanical reference system eliminates the need for complex optical tracking hardware while maintaining positioning accuracy through direct mechanical coupling and sensor-based position detection.
Solution Approach 2:
The patent extracts and removes the optical tracking components (markers, tracking arrays, optical sensors) from the system. By taking out these complex optical elements and replacing them with a simplified mechanical reference and sensor system, the invention reduces device complexity while preserving the essential function of tracking surgical instrument position relative to the bone.
2Reliability
If optical markers are used for tracking, then surgical navigation is enabled, but visibility must be guaranteed and line of sight is constrained
Solution Approach 1:
The patent replaces the optical tracking system with a mechanical reference system that does not depend on line of sight. The mechanical reference element is rigidly fixed to the bone and coupled through a kinematic chain to the surgical tool holder, allowing tracking regardless of visibility conditions. This eliminates the constraint on surgical staff positioning that exists in optical systems where markers must remain visible.
3Measurement precision
If markers are screwed onto bone to create tracking arrays, then tracking capability is improved, but risk of fracture increases and operating time lengthens
Solution Approach 1:
The patent replaces the invasive marker implantation system with a non-invasive mechanical reference system. Instead of screwing markers into the bone, the invention uses a mechanical reference element that is rigidly fixed to the bone in a manner that does not create fracture risks, and couples this reference to the surgical tool holder through a kinematic chain. This eliminates the harmful effect of bone fracture while maintaining tracking precision.
4Ease of operation
If purely optical tracking is used, then non-contact tracking is achieved, but real-time control loop is not possible
Solution Approach 1:
The patent replaces purely optical tracking with a mechanical reference system that enables real-time control. The mechanical reference element coupled to the surgical tool holder through a kinematic chain allows direct mechanical feedback and real-time position detection, enabling closed-loop control that is not possible with purely optical systems.
Data Source
Figure 1~1B
Figure 2
Figure 3~4
AI summary
The invention relates to a method and a system for computer guided surgery comprising a transposition of an action, planned in a virtual environment with respect to a virtual referential Rp, to a physical action performed with a surgical tool (20) in a real operating theatre environment for orthopedic surgery of a patient.