Indexed Surgical Saw Head Coupling for Precise Blade Navigation

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Solution Overview

Problem

Existing surgical sagittal saws lack the ability to rotate and index the saw head easily and accurately, which is crucial for precise bone resection during orthopedic procedures, and there is a need for improved tracking and navigation systems to ensure precise cutting.

Innovation Solution

A surgical sagittal saw with a tool-less coupling assembly that allows the saw head to be rotated and indexed, equipped with a navigation system that tracks the position and orientation of the blade assembly, using a navigation processor to determine the blade's characteristics and position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a traditional coupling assembly is used to hold the saw blade, then the blade can be securely attached, but the saw head cannot be easily rotated or indexed to different angular positions

Engineering Contradiction:

Improveability to rotate and index saw headVSAvoidcoupling assembly structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The coupling assembly is divided into separate functional components: a coupling member with indexing features on the saw head, and a blade holder with corresponding engagement features. This segmentation allows the saw head to be rotated and indexed independently while maintaining secure blade attachment through the engaged features.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The coupling assembly incorporates movable and adjustable elements that allow the saw head to be rotated to different angular positions and locked into place. The dynamic nature of the coupling member enables easy transition between locked and unlocked states, facilitating both secure attachment and rotational flexibility.

Inventive Principle:

Principle #15Dynamics

2Manufacturing precision

If the saw head is made fixed and non-rotatable, then the structure is simple and stable, but precise bone resection cannot be achieved due to inability to adjust angular orientation

Engineering Contradiction:

Improveprecision of bone resectionVSAvoidease of rotating and indexing

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The coupling assembly includes pre-configured indexing features and engagement mechanisms that are prepared in advance to accept specific angular positions. The blade holder and coupling member are designed with predetermined mating features that enable quick locking into accurate angular orientations without requiring complex adjustment procedures.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Traditional manual alignment methods are replaced with a mechanical indexing system that provides precise angular positioning through built-in features. The coupling member and blade holder incorporate mechanical elements that automatically ensure accurate orientation when engaged, eliminating the need for complex manual alignment procedures.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If a navigation system is added to track blade position and orientation, then accurate tracking is achieved, but the device complexity and number of components increase

Engineering Contradiction:

Improvetracking accuracy of blade assemblyVSAvoidnavigation system components

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The navigation system features are integrated directly into the blade holder and coupling assembly, merging the tracking function with the existing mechanical structure. The blade holder serves dual purposes: securing the blade and providing navigation tracking capabilities, thereby reducing overall system complexity despite adding measurement functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The coupling assembly and blade holder are designed to perform multiple functions: mechanical coupling, angular indexing, and navigation tracking. By making these components multi-functional, the system achieves accurate blade tracking without adding separate dedicated navigation hardware, thus limiting the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12588912B2Surgical saw for actuating a saw blade with an oscillating head, the saw having a coupling assembly for releasably holding the saw blade

Publication Date: 2026.03.31 STRYKER EUROPEAN OPERATIONS HOLDINGS LLC

AI summary

A method of navigating a surgical saw with a navigation system having a navigation processor. The method comprising attaching a saw blade to a head of the surgical saw and determining a position of the surgical saw. The method also comprises touching a tracked pointer to one or more reference points on the saw blade and tracking the position and orientation of the tracked pointer as the tracked pointer is touched to the one or more reference points on the saw blade. The method further comprises determining an angular orientation of the saw blade based on the tracked pointer and the one or more reference points on the saw blade, and the navigation system determining the position and orientation of the saw blade relative to saw based on the position and orientation of the saw, the angular orientation of the saw blade, and a characteristic of the saw blade.