Stiff Guide Wire Anchoring Configuration
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Solution Overview
Problem
In surgical procedures, stiff guide wires often experience accidental displacement due to soft tissue retention issues and tool forces, leading to delays and potential tissue damage, especially in minimally invasive spinal surgery where precise placement is critical.
Innovation Solution
A stiff guide wire with a selectively deployable anchoring configuration, featuring a tube with longitudinally slotted deflectable strips that form an anchoring configuration upon advancement, providing enhanced retention in tissue without the need for locking mechanisms, allowing for over-the-wire deployment of tools and implants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a stiff guide wire is used to ensure precise placement, then placement accuracy is improved, but the guide wire becomes susceptible to displacement from tool forces and soft tissue retention issues
Solution Approach 1:
The guide wire is segmented into multiple functional regions: a stiff shaft portion for precise placement and a distal anchoring portion with deflectable strips for tissue engagement. This segmentation allows each region to optimize its specific function while working together to maintain overall stability.
Solution Approach 2:
The anchoring portion introduces a dimensional transition from a straight, one-dimensional shaft to a multi-dimensional anchoring configuration where deflectable strips extend radially outward. This dimensional change enables the guide wire to engage tissue in multiple directions, preventing displacement from tool forces.
2Reliability
If the guide wire is advanced into soft tissue for anchoring, then retention is improved, but the guide wire is more prone to axial migration from transferred forces
Solution Approach 1:
The deflectable strips are configured to deflect outward in a curved manner rather than extending linearly. This curved configuration allows the strips to engage soft tissue more effectively, creating mechanical interlocking that resists axial migration forces while maintaining retention.
Solution Approach 2:
The guide wire exhibits parameter changes in its mechanical properties along its length: the shaft portion is stiff and rigid for placement accuracy, while the anchoring portion contains deflectable strips with different mechanical characteristics that allow controlled deformation for tissue engagement and migration resistance.
3Ease of operation
If reamers or drills are used to remove tissue surrounding the guide wire, then access for implant placement is improved, but the guide wire anchoring length is reduced
Solution Approach 1:
The guide wire is segmented such that the shaft portion maintains its full length for anchoring while the distal anchoring portion with deflectable strips is positioned to engage tissue at the target location. This segmentation allows reamers and drills to access the target area without compromising the anchoring length of the shaft portion.
Solution Approach 2:
The deflectable strips act as an intermediary mechanism between the guide wire shaft and the surrounding tissue. They provide the anchoring function without requiring the shaft itself to be in direct contact with the tissue at the implant placement site, allowing tools to pass through without reducing anchoring length.
4Ease of operation
If a detachable actuator is added to enable tube advancement, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The actuator is designed to be detachable and reusable, allowing dynamic engagement and disengagement during the surgical procedure. This enables the tube to be advanced for anchoring deployment and then removed for tool access, providing operational flexibility without requiring permanent complex integration.
Solution Approach 2:
The actuator is extracted as a separate, detachable component rather than being permanently integrated into the guide wire structure. This allows the actuator to be removed after serving its purpose of enabling tube advancement, simplifying the overall device configuration during different phases of the procedure.
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 anchoring configuration effectively prevents axial migration of the guide wire, ensuring precise placement and reducing procedural delays, while maintaining accessibility for tool deployment and easy removal.
Implementation Method 1
a region of the tube is longitudinally slotted to form a plurality of deflectable strips so that advancing of the tube relative to the central rod causes outward deflection of the deflectable strips to form an anchoring configuration
Implementation Method 2
each of the deflectable strips is formed with a thinned deflection region that lies between a proximal portion and a distal portion of the deflectable strip, the outward deflection generating bending of the deflectable strips in the deflection regions so that the proximal portion and the distal portion of each deflect-able strip form an acute angle therebetween
Data Source
AI summary
A device (10) which serves as a stiff guide wire for surgical procedures includes a tube (12) having an internal channel, and a central rod (14) in close-fitting sliding engagement within the tube. The tips of the tube and the central rod are in rigid mechanical engagement or interconnection. A region of the tube (112) is longitudinally slotted to form deflectable strips (18) so that advancing of the tube (12) relative to central the rod (14) causes outward deflection of the strips (18) to form an anchoring configuration. The central rod (14) and the tube (12) together define a stiff guide wire preferably having a length-to-width ratio in excess of 100:1.