Endoscopic Optical Calibration for ACL Tunnel Placement
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Solution Overview
Problem
There is considerable variability in the placement of tunnels during ACL reconstruction, leading to high failure rates due to technical errors, particularly in the malposition of femoral and tibial tunnels, which affects the stability and longevity of the knee joint.
Innovation Solution
A method and system for calibrating an endoscopic optical system using a calibration assembly that accounts for optical distortion, allowing for precise registration of a three-dimensional bone model with the actual bone and intraoperative adjustment of tunnel paths, ensuring accurate placement of tunnels during ACL reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional ACL reconstruction methods are used without optical calibration, then the surgical procedure is simpler and faster, but the tunnel placement precision deteriorates with errors varying from 8.3 to 13.9 millimeters
Solution Approach 1:
The patent applies preliminary action by performing optical calibration before the actual surgical procedure. The calibration assembly is set up preoperatively to characterize optical distortion, and this calibration data is stored for use during surgery. This allows the surgical system to compensate for optical distortions without adding real-time complexity during the actual tunnel placement procedure.
Solution Approach 2:
The patent introduces a calibration assembly as an intermediary device that mediates between the optical system and the surgical target. This assembly includes calibration targets and distortion characterization components that indirectly measure and compensate for optical distortions, allowing accurate tunnel placement without requiring direct real-time correction during surgery.
2Reliability
If traditional ACL reconstruction without calibration is performed, then the procedure is more straightforward, but the failure rate increases to 10-15% with 61% of failures due to femoral tunnel malposition
Solution Approach 1:
The calibration is performed in advance before surgery to establish distortion characteristics. This preliminary characterization of optical distortion allows the surgical planning software to pre-compensate for expected errors, thereby improving reliability without adding complexity during the critical surgical phase when tunnels are being placed.
Solution Approach 2:
The system implements feedback by using the calibration data to continuously correct and refine tunnel placement guidance. The distortion characterization function provides feedback to the surgical navigation system, allowing real-time compensation for optical distortions and improving the success rate of tunnel placement while managing system complexity through software-based correction.
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 approach reduces the variability in tunnel placement, decreases the rate of technical failures, and enhances the stability and longevity of the knee joint by providing a more accurate and reliable method for ACL reconstruction.
Implementation Method 1
creating, by the surgical controller, a characterization function that characterizes optical distortion between the calibration target and a capture array of the camera head
Data Source
AI summary
Ligament repair. Some examples are directed to methods and related systems for calibration of optical equipment for use in a computer-guided endoscopic ligament repair, such as repair of an anterior cruciate ligament (ACL). Other examples are directed to methods and related systems verification of registration between three-dimensional bone models and bone visible through an endoscope during ligament repair. Yet still further examples are directed to intraoperative changes to the tunnel plans for ligament repair.