Adjustable Rod Assembly for Spinal Fixation
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Solution Overview
Problem
Current spinal fixation rods are not adjustable, making it difficult to accommodate spinal growth or deformity correction postoperatively, and their invasive implantation methods increase the risk of infection.
Innovation Solution
An adjustable elongated rod assembly comprising bone connecting elements, first and second elongate members with expansion portions, and a locking element, allowing for percutaneous insertion and postoperative adjustments to accommodate spinal growth or deformity correction, featuring a sliding and telescoping mechanism with blind and through holes for secure coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional fixed-size spinal fixation rods are used, then the surgical procedure is simpler, but the rod cannot accommodate spinal growth or deformity correction postoperatively
Solution Approach 1:
The rod assembly is divided into multiple segments: a first rod portion, a first expansion portion with blind bore holes, a second expansion portion with through holes, and a locking element. This segmentation allows the rod to be adjusted in size by selecting different hole combinations while maintaining structural integrity.
Solution Approach 2:
The rod assembly transitions from a static fixed-size rod to a dynamic adjustable structure. The telescoping expansion portions with multiple hole positions enable the rod to change its effective length and configuration to accommodate spinal growth or deformity correction postoperatively.
2Object-affected harmful factors
If traditional open surgical implantation method is used, then the rod can be securely implanted, but the invasiveness of surgery increases and postoperative infection risk increases
Solution Approach 1:
The first expansion portion is nested within the second expansion portion, creating a telescoping structure. This nested design allows the rod components to be inserted through small percutaneous openings while maintaining secure implantation, reducing surgical invasiveness and infection risk.
3Adaptability or versatility
If the rod assembly includes multiple expansion portions with multiple holes for adjustment, then postoperative adjustments are enabled, but the device complexity increases
Solution Approach 1:
The multiple holes in the expansion portions serve multiple functions: they enable intraoperative size adjustment, accommodate spinal growth postoperatively, and allow deformity correction. This multi-functionality justifies the increased number of holes while providing comprehensive adaptability.
Solution Approach 2:
The rod assembly includes a locking element that can be inserted through aligned holes to secure the telescoping portions at the desired configuration. The self-locking mechanism simplifies the adjustment process and maintains the selected size without requiring additional complex fastening systems.
4Object-affected harmful factors
If percutaneous insertion method is used, then surgical invasiveness is reduced, but the difficulty of precise rod insertion increases
Solution Approach 1:
The rod assembly is pre-configured with multiple holes at specific positions and orientations in the expansion portions. This preliminary arrangement of holes allows for precise alignment and insertion through small percutaneous openings, reducing surgical invasiveness while maintaining insertion accuracy.
Data Source
AI summary
An adjustable rod for spinal corrective surgery is provided that includes a first elongate member and a second elongate member, each having rod portions couplable to one or more bone connecting elements and expansion portions slidably moveable with respect to one another. A plurality of holes in each expansion portion are alignable with one another to choose the length of the adjustable rod and a locking element is inserted through a pair of aligned holes to couple the first and second elongate members and secure or fix the length of the expandable rod.