Off-Axis Vertebral Augmentation Through a Single Cannula
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Solution Overview
Problem
Existing vertebral augmentation techniques using a unipedicular approach face difficulties in inserting instrumentation, such as a stylet with a shape memory shaft, through a small cannula hub and into the vertebral body, due to the need for off-axis access, which often requires twice the trauma and instrumentation.
Innovation Solution
A system and method utilizing a telescoping introducer device with a flexible distal portion and a hub assembly that allows for the stylet to be inserted off-axis by transitioning between constrained and unconstrained states, enabling access to the vertebral body through a single cannula, and further incorporating a balloon assembly for cavity creation and curable material delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a unipedicular approach is used to access the vertebral body, then the number of access cannulas and instrumentation is reduced, but the difficulty of inserting the stylet through the small cannula hub and into the vertebral body increases
Solution Approach 1:
The introducer device incorporates a telescoping shaft with multiple sections that can extend and retract dynamically. This allows the stylet to be inserted through the cannula hub when the shaft is in a retracted state, and then the shaft can extend to provide off-axis access to the vertebral body, resolving the contradiction between reduced instrumentation and ease of insertion
Solution Approach 2:
The system enables off-axis access by allowing the stylet to be positioned at an angle relative to the cannula shaft axis. The telescoping mechanism allows the stylet to emerge from the cannula hub and be oriented at different angles, providing access to locations offset from the longitudinal axis of the access cannula
2Adaptability or versatility
If a bipedicular approach is used to access the vertebral body, then access to locations on the contralateral side is achieved, but the trauma to tissue and instrumentation required doubles
Solution Approach 1:
The introducer device is segmented into multiple telescoping shaft sections that can be extended incrementally. This allows the stylet to be inserted through a single cannula and then extended to reach contralateral locations within the vertebral body, achieving the versatility of a bipedicular approach while using only one access cannula and reducing tissue trauma
Solution Approach 2:
The single access cannula with telescoping introducer device serves multiple functions: it provides access to both ipsilateral and contralateral locations within the vertebral body, eliminating the need for separate access cannulas required by a bipedicular approach, thus reducing overall instrumentation and tissue trauma
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
Facilitates simpler and less invasive vertebral augmentation by allowing off-axis access with reduced tissue trauma and instrumentation, enhancing the efficiency of vertebral body stabilization and height restoration.
Implementation Method 1
The stylet includes a stylet shaft extending a length between a proximal end and a distal end and having a flexible distal portion near the distal end. The flexible distal portion has a pre-set curve in an unconstrained state and is movable between the unconstrained state and a constrained state in which the flexible distal portion is substantially straight.
Data Source
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AI summary
A System for stabilizing a vertebral body is provided. The system includes an access cannula, introducer device, and a stylet having a stylet shaft. The access cannula includes a hub portion and a cannula shaft. The cannula shaft includes a proximal end and an opposing distal end positionable within the vertebral body. The cannula shaft defines a lumen along a longitudinal axis. The introducer device comprises a hub assembly and a pivoting member that is configured for coupling to the hub portion of the access cannula. The introducer device controls the movement of a flexible distal portion of the stylet shaft from within the introducer device through the access cannula to within a target site in the vertebral body, wherein the flexible distal portion is moved from a constrained to an unconstrained state to, e.g., displace cancellous bone within the target site.