Rotatable Guide Bushing for Progressive Bone Canal Reaming

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Solution Overview

Problem

Current surgical reaming systems for enlarging bone canals during orthopedic surgery often require multiple reamers with different cutting diameters, which can be cumbersome and may cause stress and heat issues when attempting to enlarge bores in a single step, especially in hard materials.

Innovation Solution

A kit of reamers with flutes of varying diameters and a single rotatable bushing with recesses to maintain coaxial alignment, allowing for progressive enlargement of bores using a series of reamers with the same inner shaft diameter, facilitated by a bushing holder for fixed alignment with the bore.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple reamers with different cutting diameters are used for progressive reaming, then the ability to create different size bores is improved, but the device complexity and ease of operation deteriorate due to managing multiple different reamers

Engineering Contradiction:

Improveability to create different size boresVSAvoidnumber of different reamers in set

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A single guide bushing is designed to accommodate multiple reamers of different cutting diameters through a universal interface. The bushing contains a central bore and multiple recesses that can receive flutes from reamers of varying sizes, allowing one bushing to perform the guidance function for the entire set of reamers rather than requiring separate guide elements for each reamer size.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The guide bushing combines multiple functional elements into a single component: it integrates the central bore for shaft passage, multiple recesses for flute reception, and the guide bore for alignment into one unified structure. This merging eliminates the need for separate guide components for each reamer size and simplifies the overall reaming system.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If multiple reamers with different cutting diameters are used, then different size bores can be created, but the ease of operation worsens due to the cumbersome nature of managing multiple reamers

Engineering Contradiction:

Improveability to create different size boresVSAvoidconvenience of managing multiple reamers

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The guide bushing serves as a universal guide for all reamers in the set. Each reamer, regardless of its cutting diameter, can be inserted into the same bushing through the central bore and engaged with the recesses, eliminating the need for surgeons to manage separate guide components for each reamer size and simplifying the operational workflow.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If reaming is attempted in a single step with large diameter increase, then productivity is improved, but stress and heat generation worsen especially in hard materials

Engineering Contradiction:

Improvespeed of bore enlargementVSAvoidstress and heat generation

Core Design Contradiction:

ProductivityVSStress or pressure

Solution Approach 1:

The reaming process is segmented into multiple incremental steps, each removing a small amount of material. The guide bushing facilitates this segmentation by providing precise alignment for each incremental reamer, allowing the total material removal to be divided into manageable stages that reduce stress and heat generation while maintaining high overall productivity.

Inventive Principle:

Principle #1Segmentation

4Device complexity

If a single guide bushing accommodates multiple reamers with different flute diameters, then device complexity is reduced, but manufacturing precision requirements increase to ensure proper alignment

Engineering Contradiction:

Improvenumber of guide componentsVSAvoidalignment precision of recesses and flutes

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The guide bushing incorporates locally optimized features: the central bore provides precise alignment for the reamer shaft, while the recesses are specifically shaped and positioned to engage the flutes at correct angular orientations. This local quality approach ensures that each interaction point (shaft-bore, flute-recess) has the precise geometry needed for proper alignment, accommodating multiple reamer sizes without compromising precision.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS7867234B2Reamer bushing

Publication Date: 2011.01.11 HOWMEDICA OSTEONICS CORP

AI summary

A kit including tools or instruments for reaming a series of progressively larger bores in a work piece has as least two reamers of different reamers. Each of the reamers has a plurality of cutting flutes extending radially from a central shaft of the reamer. The flutes of each of the at least two reamers extend at a different radial distance from the shaft with the inner shaft of each reamer having the same diameter. A rotatable guide bushing has a recess for receiving each of the flutes of the at least two reamers with the recesses open to a central bore in the bushing. The central bore has a diameter equal to or greater than the shaft diameters of the reamers and acts as a guide to keep the rotational axis of each reamer aligned with the central axis of the bushing bore. A holder is provided to fix the bushing with respect to the bore in the work piece.