Expandable Hood Tissue Ligation Device for Variceal Bleeding
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Solution Overview
Problem
Current endoscopic treatments for varices, such as endoscopic band ligation, face challenges in effectively reducing variceal wall tension and preventing bleeding, particularly in patients with medium or large varices, and often result in deep ulcerations and limited visibility during procedures.
Innovation Solution
A tissue ligation device comprising a catheter with an expandable hood and a suture system that allows for mechanical strangulation of tissue through a 'through the scope' technique, enabling ligation and strangulation of varices without the need for additional intubation or caps, providing improved visibility and reduced risk of complications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If endoscopic band ligation is used to treat varices, then variceal wall tension is reduced and bleeding is prevented, but deep ulcerations occur and visibility during the procedure is limited
Solution Approach 1:
The device segments the ligation function into two independent components: an expandable hood for tissue capture and a suture system for ligation. This segmentation allows the hood to be pulled back after expansion, exposing the ligation site and improving visibility while maintaining effective variceal capture and ligation
Solution Approach 2:
The hood transitions from a collapsed state to an expanded three-dimensional state to capture the varix, then returns to a collapsed state to allow retraction. This dimensional change enables effective tissue capture during expansion while improving visibility during retraction, resolving the contradiction between effective obliteration and visibility
2Ease of operation
If a plastic hollow cylinder or cap is attached to the endoscope tip for band ligation, then the elastic band can be slipped over the tissue, but visibility during the procedure is limited and the device complexity increases
Solution Approach 1:
The expandable hood serves multiple functions: capturing the varix during expansion, providing a platform for suture placement, and enabling visibility improvement through retraction. This multi-functionality eliminates the need for separate caps or attachments, reducing device complexity while maintaining ease of operation
Solution Approach 2:
The hood is designed to dynamically transition between expanded and collapsed states. When expanded, it captures tissue effectively; when collapsed, it allows retraction and improved visibility. This dynamic design provides the versatility needed for effective ligation without requiring multiple static components
3Ease of operation
If the catheter outer diameter is made smaller to fit through endoscope channels, then the device can be inserted through standard channels, but the expandable hood size is constrained
Solution Approach 1:
The catheter and hood are designed with dynamic expansion capability. The collapsed hood fits through standard endoscope channels with a small profile, while the expandable hood can inflate to a larger volume at the target site to effectively capture and ligate varices of various sizes
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 device allows for efficient ligation and strangulation of varices with reduced procedural time and sedation requirements, minimizing deep ulcerations and complications, while enabling effective treatment of variceal bleeding and prevention of re-bleeding.
Implementation Method 1
a suction port in communication with a suction source in an operative configuration
Data Source
AI summary
Tissue ligation devices and methods are provides to mechanically strangulate abnormal or undesirable tissue. Tissue ligation devices include a catheter having an outer diameter smaller than the inner diameter of a standard endoscope channel such that the catheter can be inserted into the endoscope. Tissue ligation devices also include a ligation system with an expandable hood disposed located at the distal end of the catheter. A suture extends through a lumen of the catheter and has a distal loop portion exposed outside of the expandable hood.