Lower-Limb Osteotomy Guidance With Tracker-Based Laxity Compensation
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Solution Overview
Problem
Current osteotomy procedures for correcting lower limb misalignment face challenges due to uncertainties in alignment measurements caused by joint laxity and soft tissue influence, leading to lengthy surgeries and excessive X-ray exposure, as existing navigation systems lack automatic planning based on these factors.
Innovation Solution
A method and system using tibial and femoral trackers to simulate joint laxity and soft tissue influence, allowing for precise determination and monitoring of alignment parameters, enabling accurate surgical planning and reduction of surgical iterations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If intraoperative X-ray images are acquired to guide the surgical procedure, then alignment control is improved, but patient exposure to radiation increases and surgery duration increases
Solution Approach 1:
The patent introduces optical trackers and a navigation system as an intermediary method to guide the osteotomy procedure. Instead of relying on repeated X-ray imaging, the system uses optical tracking of fiducial markers attached to the bone to provide real-time alignment information, thereby reducing radiation exposure while maintaining measurement precision
Solution Approach 2:
The patent replaces the mechanical/radiological measurement system (X-ray imaging) with an optical tracking system. The navigation system uses cameras to detect fiducial markers and compute alignment parameters optically, substituting the harmful ionizing radiation-based measurement method with a non-ionizing optical method
2Measurement precision
If multiple surgical gestures and intraoperative checks are performed to achieve satisfactory alignment, then alignment accuracy is improved, but surgery duration increases and productivity decreases
Solution Approach 1:
The patent performs preliminary computational planning of the osteotomy procedure based on preoperative imaging and simulated laxity conditions. The navigation system pre-calculates the optimal cut parameters and alignment targets, allowing the surgeon to execute the procedure in a single pass without multiple iterative adjustments, thereby improving productivity while maintaining alignment accuracy
Solution Approach 2:
The navigation system provides real-time feedback during the osteotomy procedure by continuously tracking the position of fiducial markers and computing current alignment parameters. This immediate feedback allows the surgeon to make precise adjustments if needed, reducing the number of iterative surgical gestures required while ensuring alignment accuracy
3Ease of operation
If alignment measurements are performed with the patient's leg placed on the operating table, then the surgical procedure is simplified, but measurement precision deteriorates due to uncertainties from joint laxity and soft tissue influence
Solution Approach 1:
The patent performs preliminary computational simulation of joint laxity and soft tissue influence using preoperative imaging data. The system calculates correction factors that account for these physiological factors before the actual surgery, allowing alignment measurements to be taken in the simplified supine position while compensating for the measurement errors through computational correction
Solution Approach 2:
The patent creates a virtual model (copy) of the patient's limb geometry and soft tissue characteristics from preoperative imaging. This digital replica is used to simulate the effects of laxity and soft tissue on alignment measurements, allowing the system to correct actual intraoperative measurements and achieve precise alignment without complicating the surgical procedure
Data Source
AI summary
The present disclosure relates to a method for guiding an osteotomy procedure on at least one bone selected from a tibia and a femur pertaining to a patient's lower limb to correct a misalignment of said lower limb, wherein a tibial tracker is fixed to the tibia and a femoral tracker is fixed to the femur, comprising:receiving at least one target alignment parameter of the lower limb;determining a position of a set of characteristic points on at least one of the tibia and the femur relative to at least one of the tibial tracker and the femoral tracker;applying mechanical constraints to the lower limb to bring the lower limb in a constrained position simulating laxities and/or soft tissues influencetracking positions of said characteristic points relative to at least one of the tibial tracker and the femoral tracker based on localization data of the set of characteristic points during application of said mechanical constraints,determining at least one alignment parameter of the lower limb in said constrained position, based on the positions of the characteristic points;based on the at least one target alignment parameter and on the at least one alignment parameter of the lower limb in the constrained position, determining at least one correction parameter of the osteotomy procedure to be applied to the lower limb to achieve the target alignment parameter.