Magnetic Position Tracking for Orthopaedic Implant Alignment
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Solution Overview
Problem
The challenge in orthopaedic implantation, particularly with intramedullary nails, lies in accurately positioning distal locking screws and aligning drills for distal screw holes, as current methods rely heavily on manual skills and radiation-based imaging, leading to inaccuracies and increased risk of nail breakage or drill bit failure.
Innovation Solution
A magnetic position tracking system that includes a field generator, an orthopaedic implant with a magnetic sensor and a landmark identifier, allowing for the calculation of landmark position relative to the implant, enabling precise alignment and drilling without fluoroscopy, and allowing proximal locking before distal locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual techniques with jigs and x-ray imaging are used to locate and drill distal screw holes, then the surgeon can perform the procedure with current equipment, but the positioning accuracy deteriorates due to nail deformation and manual skill limitations
Solution Approach 1:
The patent replaces manual mechanical techniques (jigs, x-ray imaging, eye-balling) with a magnetic field-based tracking system. Magnetic sensors detect landmarks on the implant to provide real-time positional feedback, eliminating reliance on manual skill and radiation-based imaging, thereby improving positioning accuracy and reducing surgical risks
Solution Approach 2:
The system incorporates real-time feedback through magnetic sensors that continuously monitor the position of drill bits relative to implant landmarks. This feedback loop allows the surgeon to adjust drilling position dynamically, preventing inaccurate entry points that could cause nail or drill bit failure
2Loss of information
If fluoroscopy is used for imaging during the procedure, then the surgeon can visualize the implant, but radiation exposure increases for both surgeon and patient
Solution Approach 1:
The patent substitutes fluoroscopy (radiation-based imaging) with a magnetic field-based tracking system. Magnetic sensors detect landmarks on the implant to provide real-time positional information without ionizing radiation, eliminating the harmful radiation exposure while maintaining visibility of implant position
Solution Approach 2:
The system introduces magnetic fields as an intermediary between the implant and the detection system. Instead of using penetrating radiation (x-rays), the magnetic field serves as a safe mediator that carries positional information from the implant landmarks to the sensors, enabling visualization without radiation harm
3Reliability
If proximal locking is performed first with a jig, then the initial locking is secured, but nail deformation during insertion makes the jig inaccurate for distal screws
Solution Approach 1:
The magnetic tracking system provides real-time feedback on drill bit position relative to implant landmarks during distal screw drilling. This active feedback compensates for nail deformation that occurred during insertion, allowing the surgeon to maintain accurate positioning despite the jig's inaccuracy, thereby resolving the contradiction between securing proximal locking and achieving distal screw precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This system reduces radiation exposure, enhances accuracy by eliminating manual eye-balling, and allows for safer implantation by ensuring correct alignment and positioning of screws, thereby reducing the risk of implant or drill bit failure.
Implementation Method 1
a field generator for generating a magnetic field
Implementation Method 2
a landmark identifier having a second magnetic sensor; and a processor for comparing sensor data from the first and second sensor
Data Source
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AI summary
A system (10, 110) for identifying a landmark is disclosed. The system includes a field generator (16, 116) for generating a magnetic field, an orthopaedic implant (30, 130) located within the magnetic field, the implant having at least one landmark (31) and a first magnetic sensor (32) spaced apart from the landmark, a landmark identifier (18, 118) with a second magnetic sensor (20, 120) and a processor (12, 112) for comparing sensor data from the first and second sensor and using the set distance to calculate the position of the landmark identifier relative to the at least one landmark. The system allows for blind targeting of one or more landmarks.