Expandable Braided Conduit Guide for Minimizing Tissue Damage
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Solution Overview
Problem
Medical devices with large diameters or inappropriate surfaces often cause injuries when tunneling through tissue to access the heart or other organs, as existing methods require large tissue punctures and direct visualization for secure placement and exchange.
Innovation Solution
An expandable conduit-guide made of braided wire with a flexible membrane that actively expands to accommodate medical devices, allowing for minimal tissue puncture and easy access, and passively collapses upon device removal, using a spring-loaded mechanism and tissue compression for secure positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a medical device with large diameter is used to provide necessary fluid conduit capacity, then fluid flow capability is improved, but tissue damage during tunneling increases
Solution Approach 1:
The conduit-guide employs a dynamic structure that transitions from a compressed low-profile state during insertion to an expanded high-capacity state after placement. The braided wire construction with memory alloy allows the conduit to dynamically change its diameter, providing minimal tissue disruption during tunneling while maintaining adequate fluid flow capacity once positioned
Solution Approach 2:
The conduit-guide is inserted in a compressed state within a delivery catheter, similar to a nested doll structure. The inner conduit is contained within the outer catheter during insertion, allowing the large-diameter conduit to be delivered through a small access site. After placement, the conduit expands from its nested state to provide the necessary fluid conduit capacity
2Strength
If a medical device with rough surface is used to provide structural integrity, then mechanical strength is improved, but tissue irritation and injury increase
Solution Approach 1:
The conduit-guide applies different surface qualities to different regions: the internal structure uses a braided wire construction for structural integrity, while the external surface is covered with a smooth biocompatible material (such as Dacron or Teflon) that minimizes tissue irritation. This local differentiation of surface properties allows the device to maintain both strength and tissue compatibility
Solution Approach 2:
The conduit-guide employs composite construction combining braided wire (providing structural strength and memory) with biocompatible polymer coatings (providing smooth tissue interface). This composite material approach allows the device to simultaneously achieve mechanical integrity and minimize tissue irritation during tunneling and implantation
3Reliability
If purse-string sutures and stabilizer grommets are used to secure cannulae, then device security is improved, but surgical complexity and recovery time increase
Solution Approach 1:
The conduit-guide features self-securing mechanisms including radial expansion against tissue walls, friction fit within the tunnel, and potential tissue ingrowth through the biocompatible surface. Once expanded, the conduit maintains its position through these passive self-securing features without requiring additional active securing components, thereby simplifying the surgical procedure while maintaining device security
4Measurement precision
If direct visualization and open chest wound are used for cannula placement, then placement precision is improved, but patient trauma and recovery time increase
Solution Approach 1:
The conduit-guide serves as an intermediary tool that enables indirect placement of the final cannula. The guide is first inserted through a small percutaneous access site, then used to deliver the cannula to the correct position within the heart or vessel. This intermediary approach allows precise cannula placement without requiring open chest surgery or direct visualization, thereby reducing patient trauma while maintaining placement accuracy
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 easy and conservative placement of medical devices with reduced tissue damage, as the conduit-guide maintains a small diameter until expanded, minimizing contact with skin and tissue during insertion and allowing for secure anchoring and easy removal.
Implementation Method 1
passively collapsing from the opened diameter to the closed diameter upon withdrawal of the medical device under a spring load of the braided-wire
Implementation Method 2
actively expanding from a closed diameter to an opened diameter with the placement of the medical device positioned within the lumen
Data Source
AI summary
An expandable conduit-guide providing a leak-tight conduit through a skin between an inside of a corpus and an outside of the corpus is disclosed. The conduit-guide includes a body encompassing a lumen extending essentially axially along a center-line, and has a distal-end to be positioned outside of the corpus, and a proximal-end to be positioned inside of the corpus. The body of the conduit-guide is constructed from a braided-wire so that the conduit-guide is capable of actively expanding from a closed diameter to an opened diameter with the placement of the medical device positioned within the lumen (110) and passively collapsing from the opened diameter to the closed diameter upon withdrawal of the medical device under a spring load of the braided-wire. A catheter-sheath and a catheter-sheath-assembly, as well as to a method for applying and positioning an expandable conduit-guide (1), catheter-sheath (8) and a catheter-sheath-assembly (800) are disclosed.