Spinal Implant Collet Frictional Rod Capture
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Solution Overview
Problem
Current spinal implant systems for treating spinal disorders often require complex surgical procedures and may not provide sufficient stability or ease of use, particularly in smaller patients or for regions with limited access, due to their design and the need for threaded setscrews.
Innovation Solution
A spinal implant system featuring a low-profile bone fastener with a collar and collet configuration that frictionally engages a spinal rod using a taper lock mechanism, eliminating the need for setscrews and allowing for a reduced dorsal height orientation, suitable for small stature patients and providing strength for spinal fusion, with modular components for adjustable fit and ease of assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional spinal implant systems with threaded setscrews are used, then secure fixation of the spinal rod is achieved, but the device complexity and surgical procedure complexity increase
Solution Approach 1:
The patent removes the threaded setscrew component from the implant system, replacing it with a collet mechanism that achieves rod fixation through frictional engagement and radial compression alone. This extraction of the setscrew simplifies the device while maintaining reliable fixation through the alternative collet-based mechanism.
Solution Approach 2:
The patent replaces the threaded mechanical engagement system (setscrew threading into the rod) with a friction-based compression system. The collet uses radial compression forces applied to the rod surface, substituting the threaded mechanical fastening approach with a friction-dominated mechanical system that achieves equivalent or superior fixation.
2Reliability
If traditional bone fasteners with setscrews are used, then rod capture is achieved, but the preload on vertebrae increases and ease of operation decreases
Solution Approach 1:
The collet mechanism is designed to automatically capture and secure the spinal rod through its compression mechanism, eliminating the need for separate setscrew installation steps. The system serves itself by using the insertion force to generate the necessary radial compression for rod capture, reducing surgical complexity and improving ease of operation.
Solution Approach 2:
The collet is pre-configured with compression springs that are already under tension before rod insertion. When the rod is inserted, the springs automatically engage and compress against the rod, capturing it immediately without requiring additional fastening actions. This preliminary preparation of the compression mechanism enables immediate rod capture.
3Strength
If standard-profile bone fasteners are used, then sufficient fixation strength is achieved, but the dorsal height is increased making them unsuitable for small stature patients
Solution Approach 1:
The patent modifies the geometric parameters of the bone fastener by eliminating the protruding setscrew and using a compact collet mechanism that achieves equivalent fixation strength within a reduced dorsal height envelope. The compression-based mechanism allows for shorter overall dimensions while maintaining the necessary fixation capability through optimized force distribution.
Solution Approach 2:
The patent shifts the fixation mechanism from axial threading (along the longitudinal axis) to radial compression (perpendicular to the rod axis). This dimensional change allows the fastener to achieve secure fixation through lateral compression forces rather than longitudinal threading, enabling a more compact profile suitable for small stature patients.
4Adaptability or versatility
If modular components with adjustable fit are used, then adaptability to various patient sizes is improved, but device complexity increases
Solution Approach 1:
The collet mechanism is designed as a universal component that can accommodate various rod diameters and configurations through its adjustable compression mechanism. The same basic collet design can be applied across different fastener sizes and spinal regions, providing adaptability without requiring entirely different component designs for each application scenario.
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
The system offers improved stability and ease of use during spinal fusion procedures, reducing the preload on vertebrae and allowing for minimal force attachment, while being adaptable for various spinal regions and patient sizes, and can be assembled without instruments, facilitating quicker and less invasive surgical interventions.
Implementation Method 1
The collet is disposed with the collar such that the inner surface frictionally engages the spinal rod to capture the spinal rod with the crown
Data Source
AI summary
A spinal implant comprises a collar, and a collet including an outer surface and an inner surface. The collet is connectable with a shaft. A crown includes a surface configured for disposal of a spinal rod. The collet is disposed with the collar such that the inner surface frictionally engages the spinal rod to capture the spinal rod with the crown. In some embodiments, implants, systems, instruments and methods are disclosed.