Intraoperative Rod Shaping for Accurate Pedicle Screw Alignment
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Solution Overview
Problem
Existing methods for planning and inserting intervertebral rods in spinal surgery lack accuracy, especially in minimally invasive procedures, due to changes in screw position and orientation during surgery, leading to inefficiencies and potential need for open operations.
Innovation Solution
A system and method that uses intraoperative image processing to detect the actual position and orientation of pedicle screws, updating the planned rod shape to fit accurately with the implanted screws, optimizing spinal alignment parameters while allowing minimally invasive insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual rod bending without preoperative or intra-operative planning is used, then the procedure is simpler and faster, but the accuracy of rod positioning and alignment is poor
Solution Approach 1:
The system performs preoperative planning by detecting screw positions and orientations from preoperative images, and intraoperative verification by detecting actual screw positions from intraoperative images. This preliminary action allows the rod shape to be planned and verified before insertion, improving positioning accuracy without requiring complex real-time adjustment systems during the procedure.
Solution Approach 2:
The system provides feedback by comparing the planned rod shape (based on preoperative screw positions) with the actual screw positions detected intraoperatively. This feedback loop allows for iterative refinement of the rod shaping to ensure accurate alignment with the actual screw positions, resolving the contradiction between simplicity and precision.
2Manufacturing precision
If preoperative planning of rod shape is used, then the rod can be shaped to correct vertebral curvature, but the planned shape may not align precisely with actual screw positions due to surgical manipulations
Solution Approach 1:
The system performs preliminary detection of screw positions and orientations from preoperative images to plan the rod shape. This preliminary action captures the screw positions before surgical manipulations occur, allowing the rod to be pre-shaped according to the planned anatomy rather than requiring post-manipulation adjustments.
Solution Approach 2:
The system uses intraoperative image detection to verify actual screw positions after surgical manipulations and provides feedback to adjust the planned rod shape. This feedback mechanism ensures that the rod shape remains reliable and accurate even when surgical manipulations cause changes in screw position, resolving the contradiction between manufacturing precision and alignment reliability.
3Measurement precision
If optical navigation-based approach is used to detect screw heads, then the location can be evaluated, but the accuracy is insufficient because only the top of the screw is identified, leaving the screw angle unknown
Solution Approach 1:
The system replaces traditional optical navigation methods with image processing techniques that analyze intraoperative images to detect both the position and orientation of screws. This substitution allows for complete screw parameter detection (position and angle) by processing the visual information from images, overcoming the limitations of optical navigation that could only detect screw head locations.
Solution Approach 2:
The system uses image processing as an intermediary to detect screw parameters. Instead of directly using optical navigation tools that have limited detection capability, the image processing system acts as an intermediary that analyzes images to extract both position and orientation information, resolving the contradiction between measurement precision and detection difficulty.
4Measurement precision
If hand-held touch probe tracked by navigation system is used, then the screw location can be tracked, but the accuracy is reduced in minimally invasive procedures due to slim insertion point and intervening soft tissue
Solution Approach 1:
The system replaces the mechanical hand-held touch probe with an image processing-based detection system. This substitution eliminates the need for physical probe insertion through slim openings, allowing screw detection to be performed by analyzing intraoperative images from the surgical field, thereby improving detection accuracy without compromising the ease of operation in minimally invasive procedures.
Solution Approach 2:
The system uses image processing as an intermediary to detect screw positions and orientations. Instead of requiring direct physical contact through the slim insertion point, the image processing system acts as an intermediary that extracts screw information from images, overcoming the limitations of physical probe insertion while maintaining or improving detection accuracy.
Data Source
AI summary
A method and system for improving spinal alignment parameters of a subject, by planning the shape of an intervertebral rod for attaching to previously implanted hardware whose positions and orientations are known from intraoperative images. Once the planned shape of the rod has been prepared, determining if, when attached to the inserted hardware, a spine configuration is achieved having acceptable values of selected spinal alignment parameters. If not, the shape of the rod is amended iteratively, until the selected spinal alignment parameters have acceptable values with attachability to the implanted hardware. If, after a predetermined number of iterations, the amended shape of the rod still does not achieve acceptable values of spinal alignment parameters, while maintaining attachability to the implanted hardware, performing a spinal manipulation procedure on at least one vertebra of the spine to increase the attachability of the rod to the implanted hardware.