Tether Tensioning Instrument for Spinal Correction
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Solution Overview
Problem
Current methods for correcting spinal deformities, such as rod-based systems, are cumbersome, require complex surgical procedures, and can hinder spinal growth due to their rigidity and permanence, while tether systems lack effective methods for tensioning to achieve desired correction.
Innovation Solution
A tether tensioning device and method that includes a tensioning mechanism with a rotatable wheel or sliding lever arm to apply and control tension between bone anchors, allowing for precise adjustment and locking of the tether to correct spinal deformities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rod-based systems are used to correct spinal deformities, then mechanical strength and stability are improved, but device complexity and surgical procedure complexity increase
Solution Approach 1:
The patent replaces rigid rods with flexible tethers that have elastic properties. The tethers are made from flexible materials that allow for natural spine movement while maintaining corrective force, eliminating the need for complex rigid rod assemblies and multiple fixation points.
Solution Approach 2:
The patent changes the mechanical parameters of the correction system by using tethers with specific elastic moduli and tensioning characteristics. The tethers can be tensioned to specific forces and have varying degrees of flexibility, allowing for customized correction without complex rigid structures.
2Manufacturing precision
If rigid rod-based systems are used for spinal correction, then correction effectiveness is improved, but adaptability to spinal growth is worsened
Solution Approach 1:
The patent employs dynamic tethers that can adapt to spinal growth and movement. The elastic tethers allow for natural spine dynamics while maintaining corrective alignment, and can be adjusted or replaced as the spine grows, providing both precision and adaptability.
Solution Approach 2:
The elastic tethers automatically adjust to spinal movement and growth patterns, providing self-regulating correction forces. The system adapts to the patient's natural spine mechanics without requiring frequent surgical interventions for adjustment.
3Ease of operation
If tethers are used instead of rigid rods, then ease of operation and reduction of surgical complexity is improved, but tensioning control precision is worsened
Solution Approach 1:
The patent incorporates tensioning mechanisms with feedback control, such as ratchet systems or controlled release mechanisms, that allow for precise tensioning of the elastic tethers. The surgeon can apply and maintain specific tension forces through controlled mechanical or surgical techniques.
Solution Approach 2:
The patent replaces complex mechanical rod adjustment systems with simpler tether tensioning methods, such as controlled cutting, anchoring, or elastic pre-tensioning techniques that achieve precise tensioning through material properties rather than mechanical adjustment.
4Adaptability or versatility
If tether tensioning is performed after implantation, then adaptability to achieve desired force is improved, but loss of time during surgical procedure increases
Solution Approach 1:
The patent employs tethers that are pre-tensioned or pre-formed to the desired configuration before implantation. The elastic properties and initial tensioning are established during manufacturing or pre-surgical preparation, reducing the need for time-consuming intraoperative tensioning adjustments.
Solution Approach 2:
The patent uses rapid tensioning methods such as controlled elastic deformation, quick-set anchoring systems, or tensioning through the natural mechanics of spine placement that allow for fast application of corrective force without prolonged surgical procedures.
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
Enables efficient and controlled tensioning of tethers between bone anchors, reducing the complexity of surgical procedures and minimizing the impact on spinal growth, while providing a more effective correction of spinal deformities compared to traditional rod-based systems.
Implementation Method 1
The elasticity of the tethers prevents some of the problems with the rigidity and permanence of the rod-based systems
Data Source
AI summary
Various methods and devices are provided for tensioning a tether. In one embodiment, a tether tensioning device is provided and includes a tensioning mechanism adapted to couple to a tether extending along a path between at least two bone anchors implanted in adjacent vertebrae. The tensioning mechanism can be adapted to apply a tensioning force to the tether along the path of the tether to thereby move the tether along the path. The device further includes an actuation mechanism movably coupled to the tensioning mechanism such that the actuation mechanism is adapted to effect movement of the tensioning mechanism to control the tensioning force applied to the tether.