Offset Reamer for Oblique Glenoid Access
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Solution Overview
Problem
Conventional reamers designed for glenoid arthroplasty often require invasive techniques, such as resecting the humeral head and retracting soft tissues, to achieve adequate exposure, leading to potential nerve or blood vessel injury and increased surgical trauma due to their straight shaft design, which is not suitable for tight joint spaces with oblique or tapered implantation trajectories.
Innovation Solution
Development of offset reamers with a polyaxial shaft arrangement that allows for oblique insertion, minimizing contact with surrounding structures and reducing the need for joint distraction, featuring a reamer head with radial arms and a cannulation system for precise bone preparation without the need for extensive dissection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a straight shaft reamer design is used, then the reamer can be easily manufactured and operated, but it requires invasive surgical techniques including resecting the humeral head and retracting soft tissues to achieve adequate exposure
Solution Approach 1:
The reamer shaft is designed with an offset configuration where the longitudinal axis of the shaft is offset from the longitudinal axis of the reamer head by a predetermined offset distance. This dimensional change in the shaft geometry allows the reamer to access the glenoid through an oblique trajectory without requiring invasive surgical exposure techniques, thereby reducing surgical trauma and risk to surrounding structures while maintaining manufacturing feasibility
2Device complexity
If a straight shaft reamer design is used, then the reamer structure remains simple, but it is not suitable for tight joint spaces with oblique or tapered implantation trajectories
Solution Approach 1:
The offset shaft configuration introduces a spatial dimension that enables the reamer to navigate oblique and tapered implantation trajectories. The offset distance between the shaft axis and reamer head axis allows the cutting surfaces to engage the glenoid at the required oblique angle while the shaft approaches through a more accessible trajectory, thereby enhancing adaptability to tight joint spaces without significantly increasing overall device complexity
Solution Approach 2:
The reamer employs asymmetric geometry where the shaft and reamer head are offset from each other, creating an asymmetric configuration that is specifically adapted for oblique glenoid access. This asymmetric design allows the reamer to accommodate the natural oblique trajectory of the glenoid implantation site, improving versatility for different implantation scenarios while maintaining reasonable structural simplicity
3Device complexity
If conventional reamers are used, then the design is straightforward, but extensive dissection and joint distraction are required to achieve adequate exposure
Solution Approach 1:
The offset shaft design enables the reamer to approach the glenoid through an oblique trajectory that bypasses the need for extensive anterior dissection and joint distraction. By changing the dimensional approach of the shaft relative to the cutting head, the instrument can access the implantation site through a more direct path, thereby reducing surgical time required for exposure and dissection while maintaining straightforward design principles
Data Source
AI summary
Low profile offset reamers include reamer heads with outer diameters that are substantially greater than the overall height of the working portion, which includes the reamer head, a reamer coupler, and a working tip that supports the reamer head and reamer coupler. The overall height is measured parallel to the rotational axis of the reamer head, and the outer diameter is measured perpendicular to the rotational axis.