Spinal Rod Reduction Tool with Nested Tubes
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Solution Overview
Problem
Current spinal fixation systems require invasive surgical techniques, causing significant tissue trauma and prolonged recovery times, and lack efficient instrumentation for inserting spinal rods into bone fixation elements with securement and visualization challenges.
Innovation Solution
A reduction tool comprising an outer tube, an inner tube, and a rotatable sleeve, which facilitates the insertion of a longitudinal spinal rod into a rod-receiving channel by allowing the inner tube to be advanced non-rotationally through the outer tube, coupled with a locking cap to secure the rod within the bone fixation element, minimizing tissue trauma and enhancing visualization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If open approach surgical techniques are employed to access the spinal area, then spinal fixation systems can be implanted, but tissue trauma is significant and recovery time is prolonged
Solution Approach 1:
The surgical approach is segmented into separate incisions: one for bone fixation element placement and another for rod insertion. This segmentation allows minimally invasive access for each component, reducing overall tissue trauma compared to a single large open incision while maintaining reliable spinal fixation implantation.
2Object-affected harmful factors
If minimally invasive paraspinal approach is used, then tissue trauma is reduced, but rod insertion and securement becomes complex
Solution Approach 1:
An intermediary reduction tool is introduced to simplify rod insertion. The tool comprises an outer tube for rod insertion, an inner tube with locking cap for securement, and a rotatable sleeve as a mediator mechanism. This intermediary device transforms the complex minimally invasive rod insertion into a simplified two-step process: insertion through the outer tube followed by securement via the inner tube and locking cap.
Solution Approach 2:
The reduction tool employs a nested structure where the inner tube is disposed within the outer tube, and the locking cap is positioned within the inner tube. This nesting allows compact instrumentation that can be introduced through small incisions while providing the necessary functions for rod insertion and securement, thereby reducing device complexity despite the minimally invasive approach.
3Loss of time
If rod is inserted through the same incision as bone fixation elements, then procedure time is reduced, but visualization and securement become difficult
Solution Approach 1:
The incisions are segmented into two separate locations: one for bone fixation element placement and another for rod insertion. This segmentation provides direct visualization of the rod during insertion through the dedicated rod incision, while the separate bone fixation element incision allows independent access. The segmented approach maintains minimal procedure time by allowing sequential placement without compromising visualization or securement.
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 tool enables minimally invasive spinal fixation with reduced trauma, simplified instrumentation, and secure rod placement, reducing post-operative pain and recovery time while providing direct visualization during rod insertion.
Implementation Method 1
The rotatable sleeve is operatively associated with the inner tube and the outer tube such that rotation of the sleeve moves the inner tube with respect to the outer tube thereby advancing the spinal rod into the rod-receiving channel
Implementation Method 2
The inner tube includes a threaded outer surface that engages a threaded inner surface of the outer tube when the inner tube is slidably disposed within the outer tube
Data Source
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AI summary
A reduction tool for use in posterior spinal fixation to facilitate insertion of a longitudinal spinal rod into a rod-receiving channel formed in a bone fixation element. The reduction tool preferably includes an outer tube sized and configured to transversely receive the spinal rod therethrough, the outer tube being operatively coupled to the bone fixation element, an inner tube operatively coupled to a locking cap and slidably disposed within the outer tube, and a rotatable sleeve for rotatably advancing the inner tube with respect to the outer tube to advance the spinal rod into the rod-receiving channel formed in the bone fixation element and to couple the locking cap to the bone fixation element to thereby secure the rod within the bone fixation element.