External Bone Fixation Struts With In-Situ Length Extension
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Solution Overview
Problem
Current hexapod bone fixation systems face challenges with limited length adjustment ranges, requiring multiple strut lengths and time-consuming, costly processes for selection and assembly, which complicates acute bone corrections and increases inventory needs.
Innovation Solution
A bone fixation system with length-adjustable strut assemblies featuring externally threaded rods and bodies, allowing for adjustable lengths without replacing struts, and a mechanism for adding-on rods to extend length, providing a wide dynamic range and reducing assembly time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple struts of differing lengths are used to accommodate various platform distances, then the system can handle diverse clinical situations, but the device complexity and inventory requirements increase significantly
Solution Approach 1:
The strut assemblies incorporate telescopic mechanisms with internal struts that can extend and retract, allowing a single strut assembly to dynamically adjust its length to accommodate various platform distances. This dynamic adjustment capability eliminates the need for multiple fixed-length struts, resolving the contradiction between adaptability and device complexity
Solution Approach 2:
Each strut assembly is designed as a universal component that can serve multiple length requirements through its telescopic mechanism. The strut body portion and internal strut configuration allow a single universal strut design to replace multiple specialized struts of different lengths, reducing inventory while maintaining versatility
2Adaptability or versatility
If struts are physically swapped during bone correction processes, then the correct strut length can be selected for each stage, but the procedure becomes time-consuming and costly
Solution Approach 1:
The telescopic strut mechanism allows for dynamic length adjustment during the bone correction procedure without requiring physical strut replacement. The strut can be extended or retracted as needed, enabling stage-by-stage correction while maintaining the same physical strut assembly, thereby eliminating time loss associated with swapping struts
Solution Approach 2:
The strut assembly includes self-adjusting mechanisms that allow the operator to modify strut length in situ during the procedure. This self-service capability eliminates the need for assistant staff to retrieve and install different strut lengths, reducing both time and labor requirements
3Adaptability or versatility
If a large inventory of differing strut lengths is maintained to handle extreme initial angulations, then all clinical scenarios can be addressed, but the inventory cost and confusion increase
Solution Approach 1:
The telescopic strut design provides a continuous range of length adjustments within each strut assembly, allowing the same inventory of struts to adapt to extreme initial angulations and various clinical scenarios. This dynamic range replaces the need for maintaining a large discrete inventory of differently sized struts
Solution Approach 2:
The strut length parameter can be continuously changed within the telescopic range to match the specific requirements of each clinical scenario. This parameter adjustability allows a standardized strut inventory to handle varying distances and angulations that previously required multiple fixed-length strut variants
Data Source
AI summary
The present application provides external bone fixation systems. The systems include one or more pairs of bone fixation platforms in the form of rings or partial rings. The platforms may be coupled to corresponding bone segments. The pair of platforms are configured to accept a plurality of struts extending therebetween. The struts are configured to attach to the platforms via joints that provide three degrees of rotation. The struts are also configured such that their longitudinal length extending between the joints/platforms can be incrementally adjusted while attached to the platforms. The struts are further configured such that their total range of length adjustment can be increased by coupling at least one add-on component to the struts in situ. The lengths of each of the plurality of struts may be adjusted to arrange the platforms, and thereby the bone segment coupled thereto, in particular relative positions and orientations.