Spinal Rod Reducer Insert Mechanism for Low-Torque Assembly
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Solution Overview
Problem
Current rod reduction systems require significant twisting force, leading to user fatigue and limitations in hand usage, especially during surgical procedures.
Innovation Solution
A rod reduction system with an elongated housing and a slidable insert featuring a transverse channel and a spring-loaded mechanism, allowing for a rapid reduction mode and a driving mode to minimize twisting force, enabling easy assembly and disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If threaded zones are used to allow components to be screwed together, then the rod reduction system can be assembled and disassembled, but users must apply a large amount of twisting force leading to user fatigue
Solution Approach 1:
The system is divided into separate components (housing, insert, reducer) that can be independently assembled and disassembled. The insert can be separated from the housing, and the reducer can be separated from the insert, allowing for easy assembly and disassembly without requiring large twisting forces on a single threaded connection.
Solution Approach 2:
The insert is made slidable within the transverse channel of the housing, allowing it to move between engaged and disengaged positions. This dynamic movement enables easy assembly and disassembly by simply sliding the insert rather than screwing it, significantly reducing the twisting force required.
2Reliability
If a large amount of twisting force is required to engage components, then the threaded portions can be properly engaged, but user fatigue increases from shoulder through arm to hand
Solution Approach 1:
The slidable insert acts as an intermediary mechanism between the housing and the reducer. Instead of directly screwing the reducer into the housing (which would require large twisting forces), the insert mediates the connection, allowing the reducer to be engaged by sliding the insert along the transverse channel, thereby reducing user fatigue.
3Ease of operation
If the insert is slidable within the transverse channel, then assembly and disassembly is simplified, but the threaded portion must be precisely positioned to engage or disengage from the reducer shaft
Solution Approach 1:
The insert is pre-positioned within the transverse channel at a specific location where its threaded portion aligns with the reducer shaft. This preliminary positioning ensures that when the insert is slid into place, the threaded portions automatically engage correctly without requiring complex alignment procedures or additional precision adjustments.
4Reliability
If the threaded portion of the insert engages the threaded portion of the reducer shaft, then the reducer can be secured, but the insert must be held in the inwardly biased position requiring additional locking mechanism
Solution Approach 1:
The spring-loaded mechanism automatically maintains the insert in the inwardly biased position where the threaded portions are engaged. The spring provides continuous force to keep the insert secured, eliminating the need for additional locking mechanisms such as set screws or clamp bands. The system is self-servicing in maintaining the engaged state.
Solution Approach 2:
The spring-loaded mechanism acts as a counterweight to any forces that might disengage the insert. The spring continuously applies force to maintain the insert in the engaged position, compensating for any external forces that might attempt to separate the threaded portions, thereby securing the reducer without additional locking mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Reduces user fatigue by allowing for reduced twisting force and flexibility in hand usage, enhancing ease and efficiency during surgical procedures.
Implementation Method 1
The insert may be slidable between an outwardly displaced position and an inwardly biased position
Data Source
AI summary
Disclosed rod reduction systems include an elongated housing having a longitudinal bore and a transverse channel extending through the elongated housing at a non-zero degree angle relative to the longitudinal bore. An insert is slidable within the transverse channel between an outwardly displaced position and an inwardly biased position. The insert includes a threaded portion and a longitudinal bore alignable with the longitudinal bore of the elongated housing. A reducer is slidably receivable within the longitudinal bore of the elongated housing. The reducer may have a longitudinal bore therethrough, and a drive shaft positioned within the longitudinal bore of the reducer.