Parallel Saw Blades with Bent Teeth for Kerf Width and Bone Stress
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Solution Overview
Problem
Existing surgical saw blades struggle to perform closed profile bone cutting without placing undue stress on the bone, as they often result in kerfs that are not wide enough to accommodate orthopedic implants while minimizing bone stress, and may leave difficult-to-remove bone ridges.
Innovation Solution
A surgical saw design featuring two parallel saw blades with specific tooth configurations, including bent and fishtail teeth, to create a wider kerf while minimizing bone stress, and a retainer system for easier assembly and reduced fabrication complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the cutting means is widened to 6× its typical width to create a kerf wide enough to receive stabilizing features of implants, then the kerf width is sufficient for implant accommodation, but additional undue stress is placed on the bone being cut, to the point of possible fracture
Solution Approach 1:
The cutting means is divided into two separate parallel cutting means (first and second cutting means) instead of one wide cutting means. Each cutting means has a thickness that does not place undue stress on the bone, but together they create a kerf wide enough to accommodate implant stabilizing features. This segmentation allows the kerf to be wide without requiring any single cutting element to be excessively wide, thereby avoiding bone fracture.
2Area of stationary object
If two parallel cutting means are spaced apart to create a kerf wide enough to receive stabilizing features, then the kerf width is sufficient, but there may be a ridge of bone left between the two parallel cutting means that is difficult to remove
Solution Approach 1:
The distal tips of the cutting means are configured with different geometries - some teeth have single distal tips while others have two distal tips. This local variation in tooth geometry allows the cutting means to create a kerf with minimal or no bone ridge between the cuts, while maintaining sufficient overall kerf width for implant accommodation. The specific tooth configuration at the distal end optimizes the cut quality in the critical region where implant stabilizing features will be received.
3Stress or pressure
If reciprocating surgical saw blades with two parallel cutting means are used to reduce stress on bone, then bone stress is reduced, but other surgical objectives may not be obtained, such as adequate kerf width and absence of bone ridges
Solution Approach 1:
The two parallel cutting means are not identical - they have different tooth configurations. The first cutting means has teeth with specific distal tip geometries while the second cutting means has different tooth configurations. This asymmetry allows each cutting means to be optimized for its specific function while working together to achieve all surgical objectives: reducing bone stress, creating adequate kerf width, and eliminating bone ridges.
Solution Approach 2:
The invention adds the dimension of tooth geometry variation along the length of the cutting means. By varying the distal tip configurations of teeth at different positions and on different cutting means, the invention achieves multiple surgical objectives simultaneously. This dimensional approach to tooth configuration allows optimization of stress distribution, kerf width, and ridge elimination in a integrated design.
Data Source
AI summary
A surgical saw includes a shaft, a first saw blade mounted on the shaft, a second saw blade mounted on the shaft parallel to the first saw blade, the first saw blade having a first tooth having two distal tips, and the second saw blade having a second tooth with a distal tip, the second tooth bent towards the first saw blade and the distal tip of the second tooth aligned with a centerline between the two distal tips of the first tooth.