Multi-Filar Stimulation Lead Structure for Fracture-Resistant Removal
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Solution Overview
Problem
Temporary stimulation leads for percutaneous electrical stimulation lack sufficient fracture resistance, making them prone to failure during use and removal, and they often require surgical intervention for removal, which is inconvenient for patients.
Innovation Solution
A fracture-resistant stimulation lead designed with a multi-filar wire structure, featuring an inner and outer layer with specific winding orientations and a de-insulated portion forming an electrode, along with an anchor that extends from the helical coil structure without a helical coil structure itself, to enhance flexibility and anchoring while minimizing tissue ingrowth and withdrawal force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the lead is made rigid to remain in the target area without drifting, then positioning stability is improved, but the lead becomes more prone to fracturing during patient movement
Solution Approach 1:
The lead is divided into multiple segments including a helical coil portion and a straight anchor portion. The helical coil portion provides flexibility to accommodate patient movement, while the straight anchor portion maintains positioning stability. This segmentation allows each part to fulfill its specific function without compromising the other.
Solution Approach 2:
Different portions of the lead have different structural properties tailored to their specific functions. The helical coil portion is designed with high flexibility to move with patient motion, while the anchor portion is designed with higher rigidity to maintain stable positioning in the target area. This local differentiation of mechanical properties resolves the contradiction between overall stability and fracture resistance.
2Ease of operation
If the lead is made flexible to move with patient movement, then ease of operation is improved, but the lead drifts from the target area
Solution Approach 1:
The lead is divided into a flexible helical coil portion and a stable straight anchor portion. The helical coil portion accommodates patient movement through its flexible structure, while the straight anchor portion maintains positioning stability. This segmentation allows the lead to be both flexible enough to move with the patient and stable enough to remain in the target area.
3Reliability
If surgical intervention is used for lead removal, then complete lead extraction is achieved, but patient discomfort and procedural complexity increase
Solution Approach 1:
The helical coil portion is designed to be detachable from the straight anchor portion. During removal, the helical coil portion can be extracted first, followed by the straight anchor portion. This extraction sequence allows for complete lead removal without requiring surgical intervention, reducing patient discomfort and procedural complexity while maintaining extraction completeness.
4Stability of the object's composition
If the anchor has a helical coil structure to enhance anchoring, then tissue ingrowth is improved, but withdrawal force increases making removal difficult
Solution Approach 1:
The lead is segmented into a helical coil portion for anchoring and a separate straight anchor portion for easy removal. The helical coil portion promotes tissue ingrowth for stable anchoring during use, while the straight anchor portion is designed to be extracted after the helical coil is removed. This segmentation allows strong anchoring during therapy without creating excessive withdrawal force that would require surgical intervention.
Solution Approach 2:
The helical coil portion is designed to be removed first as a preliminary step before removing the straight anchor portion. This preliminary action allows the majority of the lead to be extracted without encountering the high withdrawal forces associated with the anchor portion, making the overall removal process easier and less invasive.
Data Source
AI summary
A lead may comprise a multiple filar wire comprising an inner core, an inner layer and an outer layer, where a portion of the inner layer is wound in a first orientation and the inner layer comprises a first number of filars of wire and where a portion of the outer layer is wound in a second orientation opposite the first orientation and the outer layer comprises a second number of filars of wire, the second number of filars of wire being greater than the first number of filars of wire. The lead may also comprise insulation covering a portion of the multiple filar wire, the portion of the multiple filar wire and the insulation comprising a helical coil structure wound in the first orientation and an anchor formed by the inner core, inner layer and outer layer extending away from the portion of the multiple filar wire, wherein the anchor comprises no helical coil structure.