Offset Drive Shaft Reamer for Minimally Invasive Joint Access
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Solution Overview
Problem
Minimally invasive surgical procedures for joint arthroplasty, such as shoulder joint replacements, face challenges in accessing the joint due to surrounding bones and tissue, often requiring large incisions that can cause tissue trauma and complications.
Innovation Solution
A minimally invasive reaming instrument with an offset flexible drive shaft and a reamer head, allowing for greater maneuverability and access to hard-to-reach bone areas by positioning the drive shaft radially outward from the cutting face axis, enabling the reamer head to navigate around obstacles and access confined spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional reamer with a straight drive shaft is used, then the structural design is simple, but the access to joints surrounded by bones and tissue is limited, requiring large incisions
Solution Approach 1:
The drive shaft is positioned offset from the cutting face axis, creating an asymmetric configuration that allows the drive shaft to be routed away from the cutting path. This enables the reamer head to access confined spaces while the drive shaft enters through a separate trajectory, eliminating the need for large incisions required by conventional symmetric designs
Solution Approach 2:
The offset drive shaft configuration introduces a spatial dimension separation between the drive shaft trajectory and the cutting face trajectory. This allows the instrument to access the joint through a minimally invasive approach by utilizing different spatial pathways for the drive shaft and cutting elements
2Ease of operation
If a large incision is made to accommodate the full profile size of the reamer, then the reamer can access the joint, but tissue trauma increases and healing time is prolonged
Solution Approach 1:
The asymmetric offset configuration allows the cutting face and drive shaft to follow different trajectories into the joint. The cutting face can be inserted through a small incision while the drive shaft is routed through a separate, offset pathway, enabling minimally invasive access without requiring a large incision that would cause significant tissue trauma
Solution Approach 2:
The offset drive shaft acts as an intermediary element that transfers rotational force to the cutting face through a gear mechanism. This allows the drive shaft to be positioned away from the cutting path, enabling the cutting face to access the joint through a minimally invasive trajectory while the drive shaft enters through a separate route
3Adaptability or versatility
If the drive shaft is positioned at the center of the cutting face, then the structure is straightforward, but the reamer cannot navigate around bone structures to access confined spaces
Solution Approach 1:
Positioning the drive shaft offset from the cutting face axis creates an asymmetric configuration that provides lateral clearance for the drive shaft relative to the cutting path. This asymmetric arrangement allows the reamer head to navigate around bone structures and access confined spaces that would be inaccessible to conventional centered designs
Solution Approach 2:
The instrument is segmented into distinct functional components with separated trajectories: the drive shaft follows one pathway while the cutting face follows another. This segmentation of the drive and cutting functions into spatially separated components enables independent optimization of each pathway for minimal invasiveness and cutting effectiveness
Data Source
AI summary
A reaming instrument includes a reamer head having a cutting face rotatable about a cutting face axis and a drive shaft operably connected to the cutting face at a point spaced radially outwardly from the cutting face axis.