Spinal Construct Adaptor for Rod Height Adjustment
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Solution Overview
Problem
Current spinal implant systems face challenges in achieving precise spinal rod reduction and stability during surgical procedures, particularly in accommodating varying patient anatomy and avoiding complications like bone/screw purchase and rod bending, which can lead to loss of interface strength and screw pull-out.
Innovation Solution
The introduction of a spinal construct adaptor with a shim that allows for intra-operative spinal rod height adjustment, enabling the shim to be positioned between the spinal rod and the bone fastener's crown, providing flexibility to customize the spinal construct configuration and prevent complete bone/screw purchase, thus maintaining tissue integrity and avoiding complications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the spinal rod is fully reduced into the bone fastener's implant cavity to achieve stability, then the spinal construct stability is improved, but the risk of bone/screw interface compromise and screw pull-out increases
Solution Approach 1:
The adaptor serves as an intermediary component positioned between the spinal rod and the bone fastener's implant cavity. It provides a controlled interface that allows the rod to be supported at a distance from the crown, preventing direct full reduction that could compromise the bone/screw interface while still maintaining spinal construct stability through the adaptor's structural support
2Manufacturing precision
If the spinal rod height is fixed during manufacturing to simplify production, then the manufacturing precision is improved, but the adaptability to varying patient anatomy decreases
Solution Approach 1:
The system introduces dynamic adjustability through the adaptor component, which can be positioned at various heights and orientations between the spinal rod and bone fastener. This allows the spinal construct configuration to be customized intra-operatively to accommodate varying patient anatomy while the rod itself maintains precise manufacturing specifications
Solution Approach 2:
The spinal construct is segmented into distinct components (spinal rod, adaptor, bone fastener) that can be independently manufactured with precise specifications and then assembled in a customized configuration. The adaptor acts as a separate adjustable segment that provides the necessary adaptability without compromising the manufacturing precision of the individual components
3Stability of the object's composition
If the spinal rod is positioned close to the crown to maximize contact and stability, then the spinal construct stability is improved, but the risk of rod bending and interface compromise increases
Solution Approach 1:
The adaptor serves as a protective intermediary that positions the spinal rod at an optimal distance from the crown, preventing direct contact that could lead to rod bending or interface compromise. It transmits loads while maintaining a safe distance, thus providing stability without the harmful effects of close positioning
Data Source
AI summary
A spinal construct adaptor comprising a member disposable between an inner surface of a bone fastener that defines an implant cavity and a spinal rod disposed with the implant cavity. A capture element is connected with the member and engageable with the spinal rod. Implants, spinal constructs, systems, instruments and methods are disclosed.