Acetabular Registration Using CT and Point Cloud Surface Matching
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Solution Overview
Problem
Conventional surgical navigation systems face challenges in accurately registering the pelvic operating area (acetabulum) during total hip arthroplasty due to anatomical features that complicate imaging and limited surgical access, particularly in isolating the acetabulum from non-target regions like the femur.
Innovation Solution
A system that utilizes pre-operative CT images and intra-operative fluoroscopy or point cloud data to isolate the pelvic operating area by applying merge rules to exclude non-target regions, and employs a navigated ball tip stylus for surface painting and palpation to define bone surfaces and determine the acetabular center of rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If pre-operative CT images are obtained for patient registration, then comprehensive anatomical information is available, but non-target regions (e.g., femur) are included in the imaging field which complicates isolation of the target surgical area (acetabulum)
Solution Approach 1:
The patent extracts and removes non-target regions (such as the femur) from the CT image data while preserving the target surgical area (acetabulum). This is achieved through automated algorithms that identify and eliminate unwanted anatomical structures from the imaging field, thereby maintaining comprehensive information about the target area while reducing complexity from non-relevant regions.
Solution Approach 2:
The patent segments the CT image data into distinct anatomical regions, separating the target surgical area (acetabulum) from non-target regions (femur and other structures). This segmentation allows the system to process only the relevant anatomical information, reducing overall processing complexity while maintaining complete information about the surgical target.
2Area of stationary object
If conventional image processing is used to register pelvic anatomy, then the entire pelvic region is captured, but the acetabulum cannot be effectively isolated from surrounding structures
Solution Approach 1:
The patent extracts the acetabulum from the broader pelvic region by removing surrounding structures and non-target anatomy. This extraction process maintains comprehensive coverage of the pelvic area in the original images while creating a refined dataset that isolates only the acetabulum, thereby improving localization precision without sacrificing overall area coverage.
Solution Approach 2:
The patent applies different processing qualities to different regions: comprehensive imaging coverage is maintained for the entire pelvic region, while enhanced precision is applied specifically to the acetabulum area. This local quality approach ensures that the target structure receives focused, high-precision processing while the broader area maintains adequate coverage.
3Ease of operation
If manual registration methods are used, then surgical access is simple, but registration accuracy is reduced due to anatomical complications
Solution Approach 1:
The patent implements self-service through automated algorithms that perform the complex task of isolating and registering the acetabulum without requiring manual intervention. The system automatically identifies, segments, and registers the target anatomy, maintaining simple surgical access procedures while achieving high registration accuracy through computer-based image processing.
Data Source
AI summary
A system for computer assisted navigation during surgery includes a computer platform that operates to register a target surgical area of a patient. In certain cases, a process includes: obtaining a pre-op CT image of a pelvic region of a patient and intra-operatively obtaining a point cloud data about the pelvic region with a navigated instrument, generating a 3D bone model which excludes non-targeted area such as a femur, and then merging the 3D bone model to the point cloud to register the target surgical area.