Three-Plate Sagittal Blade Cartridge for Rigid Bone Cutting
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Solution Overview
Problem
Surgical sagittal blade cartridges experience deformation and flexure when cutting through uneven bone structures, leading to suboptimal implant fitting due to non-planar cut surfaces, and increasing thickness is limited by narrow cutting guide slots.
Innovation Solution
A surgical sagittal blade cartridge with a guide bar formed by three plates, including a curved inner plate to resist deformation, and features like optical markings and apertures for alignment and registration within a navigation system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the guide bar thickness is increased to resist deformation, then the rigidity of the cartridge is improved, but the cartridge cannot be inserted through narrow cutting guide slots
Solution Approach 1:
The guide bar is divided into three separate plates (first plate, second plate, and inner plate) that are positioned adjacent to each other. This segmentation allows each plate to be thinner individually while collectively providing the necessary rigidity when assembled together, resolving the contradiction between needing thickness for strength and the constraint of narrow slot dimensions.
Solution Approach 2:
The guide bar functions as a composite structure formed by combining three plates made of the same or different materials. This composite construction provides enhanced rigidity and resistance to deformation compared to a single solid bar of equivalent thickness, allowing the cartridge to maintain structural integrity without exceeding the width constraints of cutting guide slots.
2Ease of operation
If the guide bar is made thinner to fit narrow slots, then the ease of insertion is improved, but the cartridge experiences deformation and flexure during cutting
Solution Approach 1:
By segmenting the guide bar into three thin plates that fit together, the structure achieves the necessary slim profile for easy insertion through narrow slots while maintaining structural stability through the combined strength of multiple plates working together.
Solution Approach 2:
The inner plate is positioned between the first and second plates to provide localized reinforcement in the region where rigidity is most needed during cutting operations, while the overall assembly remains thin enough for easy insertion.
3Manufacturing precision
If the cartridge rigidity is increased to prevent flexure, then the cutting precision is improved, but the device complexity increases
Solution Approach 1:
The guide bar is segmented into three plates that can be manufactured separately using standard manufacturing processes and then assembled together. This approach achieves the desired cutting precision through the combined structural integrity of the plates while avoiding the need for complex monolithic structures.
Solution Approach 2:
Three relatively simple plate structures are merged together to form the complete guide bar assembly. This combining of simple components achieves the rigidity needed for precise cutting without requiring any single component to be overly complex.
Data Source
AI summary
A surgical saw blade cartridge that includes a guide bar formed from three plates. The cartridge has a blade that extends distally from the guide bar, the blade comprising a blade head including a plurality of teeth. The guide bar may be configured to have opposed edges that define a mounting feature for orienting the guide bar within the mount the surgical saw. One of the plates may be configured to define a reference feature configured to register and/or verify the pose of the cartridge with a navigation system. A method of registering the cartridge within a known coordinate system is disclosed. The method may comprise determining the deviation between an expected position of the cartridge and an actual position of the cartridge based on the reference feature and defining a hybrid position of the cartridge within the known coordinate system based on the deviation.