Expandable Stylet Assembly for Implanted Lead Removal

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Solution Overview

Problem

Existing methods for removing chronically implanted transvenous leads and catheters are inefficient due to encapsulation by tissue, difficulty in applying traction forces, and the risk of structural integrity compromise, often requiring surgical intervention.

Innovation Solution

An apparatus comprising two or more wire stylets inserted into the lead's lumen, which expand radially upon relative longitudinal movement to engage the luminal surface, allowing for effective traction forces to be applied without distorting the lead, and can be easily repositioned or removed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traction forces are applied to remove the lead, then the lead can be extracted from the body, but the flexible lead body and internal coil stretch and distort, compromising structural integrity

Engineering Contradiction:

Improvelead removal efficiencyVSAvoidlead structural integrity

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The lead is divided into segments by the multiple expandable stylets that engage different portions of the lead body. Each stylet independently expands to contact and support a specific segment of the lead, distributing the extraction force along the lead length rather than concentrating it at one point, thereby preventing distortion and maintaining structural integrity during removal.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The extraction mechanism transitions from linear traction (one-dimensional force application) to radial expansion (three-dimensional force distribution). The stylets expand radially outward to contact the lead body from multiple directions simultaneously, providing uniform support and preventing the lead from stretching or distorting in any single direction during extraction.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of operation

If excising sheaths are advanced over the lead body to aid extraction, then traction can be applied, but access is limited to the proximal end and the lead may become damaged

Engineering Contradiction:

Improveextraction accessibilityVSAvoidlead damage risk

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The stylets are inserted through the internal lumen of the lead (nested inside), then expand outward to contact the lead body from the interior. This nested configuration allows the extraction device to be introduced through the existing lead pathway without requiring external access or additional incisions, while the internal expansion point provides stable engagement that prevents lead damage during extraction.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Duration of action of stationary object

If the lead is chronically implanted, then it provides long-term therapy, but tissue encapsulation and attachment make removal difficult

Engineering Contradiction:

Improveimplant durationVSAvoidremoval difficulty

Core Design Contradiction:

Duration of action of stationary objectVSEase of operation

Solution Approach 1:

The stylets are advanced through the lead lumen to the expansion site before extraction forces are applied. This preliminary positioning ensures that the expandable elements are already in place and properly engaged with the lead body and surrounding tissue, so that when extraction begins, the forces are immediately distributed along the lead length, preventing the stylets from slipping or causing concentrated stress that could damage the encapsulated lead.

Inventive Principle:

Principle #10Preliminary action

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

Facilitates the removal of implanted structures by providing a stable and uniform expansion force along the lead, reducing the need for surgical intervention and minimizing damage to the lead during extraction.

Implementation Method 1

the stylets are subsequently moved relative to one another in a longitudinal direction... causing the assembly to expand radially

Methodology Applied

Scientific EffectRadial expansion:

Data Source

PatentUS8092467B1Apparatus and method facilitating removal of a structure implanted in a body

Publication Date: 2012.01.10 LINDSTROM CURTIS CHARLES

AI summary

An apparatus and method facilitating removal, from a body, of an implanted elongated structure with a lumen such as a lead or catheter, comprises a plurality of wire stylets that are inserted together into the lumen and subsequently moved relative to each other in a longitudinal direction by manipulation at the proximal end. The stylets have dimensional features on their adjacent sides that mate together to minimize the overall diameter of the stylet assembly during insertion into the lumen. Interaction of the features on the stylets' adjacent sides, resulting from the subsequent relative displacement, causes the assembly to expand radially. The expansion is sufficient to engage the luminal surface of the implanted structure, thereby allowing traction forces to be applied, while minimizing deformation of the implanted structure. If repositioning of the apparatus is necessary, the stylets may be returned to initial relative positions, reestablishing a minimal overall diameter.