Telescoping Dilator with Non-Cutting Threads for Tissue Passageway
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Solution Overview
Problem
Current methods for forming a passageway through tissue for interventional medical systems, such as delivering cardiac pacing devices, lack effective configurations that minimize tissue trauma and facilitate the passage of larger devices through smaller introducer sheaths.
Innovation Solution
An apparatus with a flexible elongate shaft and a dilator featuring a tapered design with external non-cutting threads, allowing for gradual expansion and contraction of the passageway, and a wire with a pre-formed J-shape for piercing, enables the formation of a passageway through tissue with minimal trauma, accommodating larger devices for delivery through smaller introducer sheaths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a traditional needle, dilator, and introducer sheath apparatus is used to form a passageway through tissue, then the passageway can be formed for device delivery, but the tissue trauma is significant and the ability to deliver larger devices through smaller sheaths is limited
Solution Approach 1:
The dilator is designed with a telescoping structure where the outer dilator receives and guides the inner dilator, allowing nested configuration during delivery through the sheath and expanded configuration during tissue dilation. This nesting enables compact delivery while providing sufficient dilation capability for larger device delivery.
Solution Approach 2:
The dilator transitions from a compressed, nested state during delivery to an expanded, functional state during tissue passage. The telescoping structure allows dynamic adjustment of the dilator configuration to match procedural requirements at different stages.
2Area of stationary object
If a dilator with large outer diameter is used to create sufficient passageway for device delivery, then larger devices can be delivered, but the dilator cannot pass through smaller introducer sheaths
Solution Approach 1:
The telescoping dilator structure allows the dilator to be compressed into a narrow profile that fits within the introducer sheath, then expanded to create a large passageway for device delivery. The nested configuration enables the dilator to temporarily reduce its outer diameter for delivery while maintaining the capability to create sufficient passageway size.
Solution Approach 2:
The dilator dynamically changes its outer diameter from a compressed state during sheath delivery to an expanded state during tissue dilation, allowing it to pass through small sheaths while still creating large passageways.
3Strength
If a rigid dilator is used to maintain structural integrity during passage, then the dilator can withstand delivery forces, but it causes increased tissue trauma
Solution Approach 1:
The dilator features a tapered design with varying wall thickness and structural properties along its length. The proximal portion has greater structural support for delivery, while the distal portion has reduced structural rigidity to minimize tissue trauma during passage. This local variation in quality allows the dilator to maintain integrity where needed while being gentle on tissue where it contacts the passage way.
Solution Approach 2:
The dilator's structural parameters (wall thickness, rigidity) are varied along its length to optimize both delivery strength and tissue compatibility. The tapered geometry creates a gradient in mechanical properties that balances structural integrity with minimal tissue trauma.
4Object-affected harmful factors
If a tapered dilator design is used to gradually expand tissue, then tissue trauma is minimized, but the dilator requires complex configuration for delivery through sheaths
Solution Approach 1:
The telescoping structure provides a systematic method for configuring the tapered dilator for delivery. The nested design organizes the complex geometry into a compact, deliverable form that maintains the tapered profile while fitting within the sheath constraints.
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 apparatus effectively creates a passageway of sufficient size for device delivery while minimizing tissue trauma, allowing for the successful placement of implantable cardiac pacing devices and other medical devices through the interatrial septum or other tissues with reduced procedural difficulty.
Implementation Method 1
a second portion of the dilator has a decreasing taper from the first portion to a distal end of the dilator, and includes an external non-cutting thread formed along the decreasing taper
Implementation Method 2
a relatively flexible elongate shaft
Data Source
AI summary
An apparatus for forming a passageway through tissue includes a dilator mounted to a shaft, wherein the dilator includes a first portion, which has an increasing taper from a first outer diameter to a larger second outer diameter, and a second portion, which has a decreasing taper from the first portion to a distal end of the dilator, and which includes an external non-cutting thread formed along the decreasing taper. Lumens of the dilator and shaft provide a conduit for means to pierce through the tissue, for example, an elongate wire that includes a piercing tip. In some cases, the dilator first portion is expandable to, and contractible from, the larger second outer diameter, wherein the apparatus may include a spreading member configured to slide between the shaft and the first portion. The apparatus may be included in a system with an introducer sheath.