Patient-Specific Implant Design for Registration Error Tolerance
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Solution Overview
Problem
Existing preoperative planning in orthopedic surgery, particularly involving patient-specific implants, is hindered by inaccurate patient-to-image registration, leading to potential mismatch between registered and actual patient anatomy, resulting in surgical errors and imprecise outcomes.
Innovation Solution
A method to estimate and simulate surface localization error (SLE) during registration, using a Monte-Carlo approach to identify critical points for registration and adjust implant design to minimize impingement and improve fit, by applying a threshold-based analysis to detect registration errors and guide point acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If patient-to-image registration is performed using surface or anatomical landmarks, then the complexity of the procedure is reduced and additional operations are avoided, but the registration accuracy deteriorates leading to potential mismatch between registered and actual patient anatomy
Solution Approach 1:
The patent applies preliminary action by performing Monte-Carlo simulations and error analysis during the preoperative planning phase, before the actual surgery. This allows the implant design to be optimized in advance to compensate for expected registration errors, thereby achieving high accuracy without requiring complex intraoperative registration procedures or additional surgical steps.
Solution Approach 2:
The patent implements beforehand cushioning by designing implants with built-in compensation for anticipated registration errors. Through simulated error propagation, the system identifies critical regions and adjusts the implant design accordingly, creating a buffer that protects against the harmful effects of registration inaccuracies during surgery.
2Measurement precision
If fiducial screws are implanted prior to imaging to achieve high registration accuracy, then the registration precision is improved, but the procedure requires additional operations or intra-operative imaging systems increasing complexity
Solution Approach 1:
The patent performs error analysis and implant optimization during the preoperative planning phase, before surgery begins. This preliminary action allows the system to account for potential registration errors without requiring fiducial markers or complex intraoperative imaging, thereby achieving high accuracy while maintaining procedural simplicity.
Solution Approach 2:
The patent creates a virtual model of the patient's anatomy from preoperative images and performs simulations on this digital copy. This allows error analysis and implant design optimization to be performed on the digital replica without requiring physical fiducial markers or complex intraoperative measurement systems.
3Ease of manufacture
If implant design is optimized based on preoperative images without accounting for registration error, then the design process is simplified, but the implant may cause impingement or poor fit due to registration mismatch
Solution Approach 1:
The patent performs Monte-Carlo simulations and error propagation analysis during the preoperative planning phase, before the implant is manufactured. This preliminary optimization accounts for expected registration errors and adjusts the implant design accordingly, ensuring reliable fit and avoiding impingement while maintaining the simplicity of the manufacturing process.
Solution Approach 2:
The patent designs implants with built-in compensation for anticipated registration errors by analyzing error propagation in critical regions during planning. This beforehand cushioning ensures that even if registration mismatch occurs during surgery, the implant will maintain proper fit and avoid impingement on surrounding structures.
Data Source
AI summary
Disclosed herein is a method of planning orthopedic surgery. The method can include taking a scan of a patient bone, estimating a potential registration error to occur during the orthopedic surgery, and designing an implant based upon the scan and the potential registration error. The scan can be a three-dimensional scan. The implant can be a patient specific implant. The method can include modifying fixation elements based upon the scan and registration error to avoid impingement and/or disassociation with the bone.