Collapsing Coil Coupling for Lead Extraction
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Solution Overview
Problem
Current lead extraction techniques face difficulties due to scar tissue formation and attachment to vascular walls, leading to increased risk and complexity in removing leads from the body, especially when the vein walls are thin and fibrous, and existing technologies are limited in tension support and coupling reliability.
Innovation Solution
A device with a coil element that can slide over and grip the lead, featuring a ratchet mechanism to apply tension via a tether, allowing for secure engagement and extraction, including a unidirectional rotational coupling and a breakaway torque tab to prevent over-tightening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a lead is extracted from the body, then the lead can be removed for replacement or repair, but the scar tissue formation and attachment to vascular walls increase the difficulty and risk of extraction
Solution Approach 1:
The device employs a nested structure where the coil element is positioned within the lead extension, and the lead extension is inserted through the lead. This nested arrangement allows the extraction device to engage the lead from within, providing controlled extraction while minimizing damage to surrounding tissues and reducing extraction difficulty despite scar tissue formation.
Solution Approach 2:
The coil element is designed to be dynamically adjustable between a relaxed state and a compressed state. When compressed, the coil element expands to engage and grip the lead securely. This dynamic behavior allows the device to adapt to the lead's position and the forces applied during extraction, maintaining reliable engagement while facilitating safe removal despite tissue attachment.
2Ease of operation
If tension is applied to the lead for extraction, then the lead can be pulled free from tissue attachment, but the lead may become damaged or structurally fail
Solution Approach 1:
The device applies preliminary action by first engaging the coil element with the lead through controlled compression, establishing a secure grip before tension is applied. The ratchet mechanism pre-positions the coil element in an engaged state, ensuring the lead is firmly held before extraction forces are applied, thereby preventing slippage and reducing the risk of lead damage.
Solution Approach 2:
The ratchet mechanism provides beforehand cushioning by allowing controlled, incremental application of tension through the tether. The ratchet teeth engage in a staged manner, distributing the extraction force gradually rather than applying sudden high tension. This progressive loading protects the lead from structural failure while still achieving sufficient force to overcome tissue attachment.
3Reliability
If the coil element is tightened to grip the lead securely, then the coupling reliability increases, but over-tightening may cause damage to the lead
Solution Approach 1:
The ratchet mechanism provides mechanical feedback through its tooth engagement system. As the coil element is compressed and expands to grip the lead, the ratchet teeth engage incrementally, providing tactile and mechanical feedback on the tightening process. This feedback mechanism prevents over-compression by physically limiting the maximum engagement force, ensuring secure coupling without damaging the lead.
Solution Approach 2:
The device controls the compression parameter of the coil element through the ratchet mechanism. By adjusting the degree of compression in controlled increments, the system optimizes the expansion force of the coil element. This parameter control ensures the coil element generates sufficient gripping force for reliable coupling while staying within safe limits to prevent lead damage.
4Reliability
If the lead is extended to facilitate extraction, then the extraction process becomes easier and safer, but the device complexity increases
Solution Approach 1:
The lead extension serves multiple functions: it extends the lead to provide access for extraction devices, acts as a structural support during extraction, and provides a pathway for the tether and coil element. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity while achieving improved extraction safety.
Solution Approach 2:
The nested arrangement of the coil element within the lead extension, and the lead extension within the lead, creates a compact integrated structure. This nesting minimizes the overall device footprint and reduces the number of separate components that would otherwise be required, thereby limiting the increase in device complexity while maintaining the extraction safety benefits.
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 extends the lead for easier extraction by applying controlled tension and gripping the lead securely, reducing the risk of damage and structural failure during the extraction process.
Implementation Method 1
the coil element is compressible to expand and grip the lead
Implementation Method 2
the ratchet mechanism may include a unidirectional rotational coupling between a first ratchet grip and a second ratchet grip
Data Source
AI summary
A device for extending a lead according to some embodiments includes a body, a coil element coupled to the body, the body configured to cover the coil element during use, the coil element comprising an inner lumen sized to receive an outer surface of a lead, the coil element is movable between a first configuration in which the coil element slides over the lead, and a second configuration in which at least some coils grip the outer surface of the lead; and an actuation mechanism operatively coupled to the coil element, the actuation mechanism configured to move the coil element between the first and second configurations.