Non-expandable Stent with Curved Proximal Portion and Sphincter Engagement
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Solution Overview
Problem
Existing stents for occluded biliary or pancreatic ducts cause irritation and inflammation due to abrasive retaining elements, and there is a need for atraumatic placement and removal without damaging the ductal tissue, as well as effective engagement with the sphincter to prevent migration.
Innovation Solution
A non-expandable stent with a curved proximal portion and a distal retaining member configured to engage the sphincter, designed for placement proximal and distal to the sphincter respectively, minimizing contact with ductal tissue and allowing for easy removal, using a delivery system with a wireguide and introducer catheter for precise deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retaining elements such as flaps and pigtails are used to hold the stent in position, then the stent can be retained without migration, but these elements cause abrasive effect on the surrounding ductal tissue leading to inflammation and aggravation
Solution Approach 1:
The patent removes the traditional retaining elements (flaps and pigtails) from the stent structure and replaces them with a delivery system that uses a balloon to anchor the stent temporarily during deployment. This extraction of harmful components eliminates the abrasive effect on ductal tissue while maintaining stent retention through alternative means.
Solution Approach 2:
The patent introduces a balloon as an intermediary device that facilitates stent deployment and retention without direct contact between the stent's retaining elements and the ductal tissue. The balloon serves as a mediator that holds the stent in position during the procedure, preventing migration without causing tissue abrasion.
2Reliability
If traditional stents with retaining elements are placed in the duct, then they can maintain patency, but they cause aggravation to the ductal tissue particularly when removed
Solution Approach 1:
The patent removes the harmful retaining elements that cause tissue damage during removal. Instead, the stent is held in place by a balloon during deployment, and once the balloon is deflated and removed, the stent remains securely positioned without elements that would cause damage upon extraction.
Solution Approach 2:
The patent performs preliminary action by using the balloon to secure the stent in position before the actual deployment is complete. This preliminary anchoring allows the stent to be properly positioned and then released without the need for damaging retaining elements that would require forceful removal.
3Reliability
If retaining elements are used to engage the sphincter to hold the stent in position, then migration is prevented, but the retaining elements cause aggravation to the ductal tissue
Solution Approach 1:
The patent extracts the traditional retaining elements (flaps and pigtails) that cause tissue aggravation and replaces their function with a balloon-based anchoring system. The balloon engages the sphincter during deployment to prevent migration, but does not cause the same abrasive damage to the ductal tissue as the removed elements.
Data Source
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AI summary
A non-expandable stent and a method for implanting the stent are provided. The stent includes a generally tubular body having a lumen defined therethrough. The body includes a proximal portion having a curved portion configured for placement proximal to a sphincter. The body further includes a distal portion having retaining member extending outward from a proximal end of the distal portion. The retaining member is configured for placement distal to the sphincter and for engagement of the sphincter.