Surgical Cutting Tip with Translatable Outer Shield
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Solution Overview
Problem
Current lead extraction techniques face difficulties due to scar tissue formation and attachment to vascular structures, making it challenging to remove implanted cardiac pacing system leads, especially in tortuous vascular paths and structurally weak areas.
Innovation Solution
A surgical device with a sheath assembly and cutting tip mechanism that includes an intermediate sheath, inner sheath, and outer shield, allowing for controlled rotation and extension of the cutting tip to separate tissue from the lead, facilitating safe removal by transitioning between shielded and extended configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If mechanical traction and simple sheath devices are used for lead extraction, then the procedure is simpler and faster, but the ability to cut through scar tissue and attachments is insufficient
Solution Approach 1:
The device employs a nested sheath configuration with three concentric sheaths (outer sheath, intermediate sheath, and inner sheath) where each sheath contains the next smaller sheath. This nested structure allows the device to maintain a compact profile for insertion while providing multiple functional layers for cutting, shielding, and support, thereby achieving enhanced cutting capability without proportionally increasing overall device complexity.
Solution Approach 2:
The cutting function is segmented across multiple components: the inner sheath provides structural support, the intermediate sheath contains the cutting tip and provides additional support, and the outer sheath offers shielding and stability. This segmentation allows each component to be optimized for its specific function while working together to achieve the overall cutting objective.
2Strength
If a rotating cutting tip is used to separate tissue, then cutting effectiveness is improved, but control and safety are reduced due to potential contact with vascular structures
Solution Approach 1:
The intermediate sheath acts as an intermediary between the rotating cutting tip and the external environment. It provides additional structural support to the cutting tip while maintaining a shielded configuration that prevents direct contact with vascular structures. The intermediate sheath mediates the cutting action, allowing tissue separation while protecting against harmful contact with surrounding vasculature.
Solution Approach 2:
The device employs a shielded configuration where the cutting tip is enclosed within the intermediate sheath during insertion and positioning. This prior shielding protects vulnerable vascular structures from accidental contact before the cutting action is initiated. The shielded configuration serves as a preventive measure that cushions against potential harm until the cutting is deliberately activated.
3Productivity
If the cutting tip is always exposed for effective cutting, then tissue separation is improved, but safety is reduced due to potential damage to surrounding tissue
Solution Approach 1:
The device transitions dynamically between two configurations: a shielded configuration where the cutting tip is enclosed within the intermediate sheath for safe navigation and positioning, and an extended configuration where the cutting tip protrudes for active tissue cutting. This dynamic reconfiguration allows the device to optimize for safety during insertion and for cutting efficiency during the actual cutting phase, thereby achieving both protective and productive states.
Solution Approach 2:
The cutting tip is designed with localized cutting surfaces that are exposed only when needed for cutting. The intermediate sheath provides shielding in areas where surrounding tissue protection is critical, while allowing localized exposure of the cutting tip where tissue separation is required. This local differentiation of exposed versus shielded areas enables efficient cutting at the cutting interface while protecting surrounding structures.
4Reliability
If multiple sheath layers are used for protection and support, then safety and stability are improved, but device complexity and operational difficulty increase
Solution Approach 1:
Each sheath layer serves multiple functions: the outer sheath provides shielding and stability, the intermediate sheath provides structural support for the cutting tip and acts as an intermediary shield, and the inner sheath provides additional support and defines the cutting chamber. This multi-functionality of each sheath layer maximizes the protective and supportive benefits of the nested configuration while minimizing the operational complexity that would result from having separate dedicated components for each function.
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 effectively cuts and separates tissue from the lead, enabling safer and more precise extraction of implanted leads from the vascular system, even in challenging anatomical locations.
Implementation Method 1
a cutting tip, the cutting tip including a cutting surface adapted to cut tissue coupled to the implanted object as the cutting tip rotates relative to the sheath assembly
Data Source
AI summary
Devices for removing implanted objects from body vessels are provided. A device includes a sheath assembly having a cutting tip. The cutting tip includes a cutting surface that is adapted to cut tissue coupled to an implanted object as the cutting tip rotates. The sheath assembly further includes an outer shield carried outside of the cutting tip. The outer shield includes a distal opening, and the outer shield is translatable relative to the cutting tip from a first position to a second position and vice versa. In the first position the cutting surface of the cutting tip is disposed within the outer shield, and in the second position the cutting tip extends through the distal opening and the cutting surface is at least partially disposed outside of the outer shield.