Computer-Assisted Trajectory Planning for Surgical Insertion
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Solution Overview
Problem
The pre-operative planning of electrode placement for stereo-electroencephalography and other intra-cranial procedures is time-consuming and challenging due to the need for precise identification of safe trajectories that avoid critical anatomical structures, with existing methods often requiring lengthy computation times and lacking real-time interactive capabilities.
Innovation Solution
A computer-assisted method using a three-dimensional representation of the skull and critical objects, where entry points are filtered based on perpendicularity to the skull surface and risk factors are assessed by integrating distance from critical objects along the trajectory, enabling real-time and interactive planning of safer surgical insertion trajectories.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If computer-assisted planning is used to identify safe trajectories avoiding critical anatomical structures, then the precision of electrode placement is improved, but the computation time increases significantly
Solution Approach 1:
The planning process is divided into multiple independent stages: (1) defining the target area and generating candidate entry points, (2) filtering entry points based on skull surface perpendicularity, (3) assessing risk factors for remaining entry points, and (4) selecting the optimal trajectory. This segmentation allows each stage to be processed independently and efficiently, reducing overall computation time while maintaining precision.
Solution Approach 2:
Entry points are pre-filtered based on skull surface perpendicularity before the computationally intensive risk assessment stage. This preliminary filtering eliminates obviously suboptimal entry points early in the process, reducing the number of trajectories that require detailed risk evaluation and thereby decreasing total computation time.
2Reliability
If comprehensive risk assessment integrating distance from critical objects along the trajectory is performed, then the safety of surgical insertion is improved, but the complexity of the planning system increases
Solution Approach 1:
The complex risk assessment process is automated through computer algorithms that calculate distance metrics from critical anatomical structures along each trajectory. The system replaces manual surgical planning with computational methods that integrate multiple risk factors (distance to blood vessels, distance to brain tissue, entry angle) into a unified quantitative assessment, improving safety while managing complexity through automation.
Solution Approach 2:
The system transforms qualitative safety considerations into quantitative parameters by calculating specific distance measurements from the trajectory to critical objects. By changing the assessment from subjective judgment to objective parameter-based evaluation (distance metrics, angles, risk scores), the system improves reliability while making the complexity manageable through standardized calculations.
3Productivity
If real-time interactive planning capability is implemented, then the efficiency of identifying safe trajectories is improved, but the computational requirements and system complexity increase
Solution Approach 1:
The planning system is segmented into discrete, computationally efficient stages that can be executed in real-time. Each stage (entry point generation, perpendicularity filtering, risk assessment) processes data independently and quickly, allowing the system to provide interactive feedback to the surgeon without requiring excessive computational resources or time.
Solution Approach 2:
The system performs risk assessment on a subset of entry points that meet the perpendicularity criterion, rather than evaluating all possible trajectories. This partial action approach provides sufficiently accurate results for clinical decision-making while significantly reducing computational requirements, enabling real-time interactivity.
Data Source
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AI summary
A system and method are provided for using a computer system to assist in planning a trajectory (960A, 960B) for a surgical insertion into a skull. The method comprises providing the computer system with a three-dimensional representation of the skull and of critical objects located within the skull, wherein the critical objects comprise anatomical features to be avoided during the surgical insertion. The method further comprises providing the computer system with a target location (770, 970) for the insertion within the skull. The method further comprises generating by the computer system a first set comprising a plurality of entry points, each entry point (760) representing a surface location on the skull, and each entry point (760) being associated (2D) with a trajectory (960A, 960B) from the entry point (760) to the target location (770, 970). The method further comprises discarding by the computer system entry points from the first set to form a second, reduced set comprising a plurality of entry points, wherein an entry point (760) is discarded from the first set of entry points if the entry point (760) has an entry angle which fails a condition for being substantially perpendicular to the skull surface. For each entry point (760) in the second set, the computer system assess the entry point (760) against a set of one or more criteria, wherein the set of one or more criteria includes a risk factor based on the separation between the critical objects and the trajectory (960A, 960B) which is associated with said entry point (760). This risk factor may be calculated by integrating f(x) along the trajectory (960A, 960B) associated (2D) with the entry point (760), where x represents distance along the trajectory (960A, 960B) to a sample point, and f(x) is a function based on distance from the sample point at distance x to a critical object which is nearest to said sample point.