Telescoping Strut Assembly for In-Place External Fixation Adjustment
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Solution Overview
Problem
Current hexapod bone fixation systems face challenges with limited length adjustment ranges, requiring multiple strut lengths and a time-consuming selection process, which complicates clinical procedures and increases inventory costs.
Innovation Solution
The development of adjustable strut assemblies with elongate tubular members and threaded rods, allowing for both axial translation and rotation, enabling quick and large-range length adjustments while remaining coupled to platforms, thereby simplifying the selection and use of struts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple struts of differing lengths are used to meet various clinical needs, then the adaptability of the fixation system is improved, but the device complexity and inventory requirements increase
Solution Approach 1:
The strut assembly is designed to perform multiple functions: it can be adjusted to various lengths within a broad range (2 inches to 12 inches), allowing a single universal strut design to replace multiple fixed-length struts. The telescoping mechanism with nested tubes and threaded rods enables one strut to fulfill the roles of several different strut lengths, thereby improving adaptability while reducing inventory complexity
Solution Approach 2:
The strut assembly incorporates dynamic adjustment capabilities through telescoping tubes and threaded rod mechanisms. The intermediate tube can slide within the first tube, and the second tube can slide within the intermediate tube, allowing the strut length to be dynamically changed during clinical procedures. This dynamic design eliminates the need for static fixed-length struts, resolving the contradiction between adaptability and complexity
2Adaptability or versatility
If struts are physically swapped during bone correction procedures, then the length adjustment range is improved, but the loss of time and productivity decrease
Solution Approach 1:
The strut assembly allows for dynamic length adjustment during procedures through its telescoping mechanism. The threaded rods enable the tubes to be extended or retracted to the required length without removing the strut from the fixation system. This eliminates the time-consuming process of physically swapping struts while maintaining the ability to achieve various length adjustments
Solution Approach 2:
The strut assembly is designed with preliminary adjustment capabilities where the desired length can be set before final installation or adjusted quickly during the procedure. The threaded adjustment mechanisms allow the strut to be pre-configured to the needed length, reducing the time required for length changes during bone correction procedures
3Device complexity
If fixed-length struts are used to simplify the system, then the device complexity is reduced, but the adaptability and adjustment range are limited
Solution Approach 1:
The strut assembly transforms a static fixed-length design into a dynamic adjustable design. The nested telescoping tubes with threaded rod mechanisms allow the strut length to be changed while maintaining a relatively simple overall structure. The complexity is managed through standardized components that work together to provide adaptability without requiring multiple different strut designs
4Adaptability or versatility
If a large inventory of differing strut lengths is maintained, then the adaptability is improved, but the loss of substance and cost increase
Solution Approach 1:
The universal adjustable strut assembly can replace an entire inventory of multiple fixed-length struts. A single design with adjustable length capabilities (2-12 inches) can fulfill the needs that previously required maintaining stock of numerous different strut lengths. This reduces inventory requirements and associated costs while preserving full adaptability for various clinical scenarios
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
This solution provides a stable and mobile external fixation system with a broad adjustment range, reducing the need for multiple strut lengths and minimizing the time and inventory required for clinical procedures, allowing for efficient bone or tissue correction.
Implementation Method 1
a threaded rod fixed within an axial internal cavity of the intermediate member. An axial cavity of the second member is threadably coupled with the threaded rod within the cavity of the intermediate member
Data Source
AI summary
Length-adjustable strut assemblies for external fixation systems, and corresponding external fixation systems, are disclosed. The strut assemblies include an elongate first and second end members, an elongate intermediate member, and first and second adjustment mechanisms. The intermediate member comprises a threaded rod fixedly coupled within an axial cavity thereof, and is rotatably fixed and axially translatably within an axial cavity of the first end member. An end portion of the second end member is received within the axial cavity of the intermediate member, and the second end member comprises an axial cavity threadably coupled with the threaded rod. The first adjustment mechanism is configured to selectively axially fix the intermediate member relative to the first end member. The second adjustment mechanism is configured to selectively rotate the second end member with respect to the threaded rod to axially translate the second end member relative to the intermediate member.