Spinal Cord Stimulation Lead with Flap Fixation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Implantable medical electrical leads face challenges in maintaining precise positioning along the spinal cord during and after implantation, with issues of longitudinal and transverse movement leading to reduced efficacy and increased power consumption, and difficulties in advancing the lead through ligamentous structures.
Innovation Solution
The design includes an elongate lead body with a distal region featuring a flap that can move from a constrained to an extended position to maintain electrode positioning against the spinal cord, and a system comprising a tubular catheter and pusher element to facilitate precise placement and stabilization of the lead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a stiffening member or stylet is used to advance the lead through ligamentous structures, then the lead can be advanced more easily, but the stylet may buckle during the implantation procedure
Solution Approach 1:
The lead is divided into segments with different stiffness characteristics - a more compliant proximal portion for navigation and a stiffer distal portion for stable electrode placement. This segmentation allows the lead to be advanced through ligamentous structures without requiring a separate stylet that may buckle
Solution Approach 2:
The lead's stiffness parameter is varied along its length, with the distal portion having increased rigidity compared to the proximal portion. This gradient in stiffness allows easy advancement while maintaining structural integrity and preventing buckling during implantation
2Reliability
If the lead remains fixed in position after implantation, then electrode positioning is maintained, but the lead may be dislodged during surgical procedure or physical activity
Solution Approach 1:
The lead incorporates a dynamic fixation mechanism where flaps or wings can transition from a compressed delivery state to an expanded deployed state. This allows the lead to adapt to tissue contours and achieve stable fixation while maintaining flexibility during implantation
Solution Approach 2:
The flaps are positioned asymmetrically on the lead body, with specific orientation relative to the electrode array. This asymmetric configuration provides directional stability and prevents rotation or dislodgement while maintaining optimal electrode-spinal cord contact
3Power
If surface electrodes are positioned closely along the spinal cord, then signal strength is improved, but the lead may move longitudinally or transversely
Solution Approach 1:
The fixation flaps extend in a dimension perpendicular to the lead's longitudinal axis, providing transverse stabilization. This dimensional addition prevents both longitudinal migration and transverse displacement while maintaining close electrode-to-spinal-cord positioning for optimal signal strength
Data Source
AI summary
Devices and methods for implanting a spinal neurological lead having at least one wing or flap extending transversely from the lead body. The wing can have a first wrapped configuration in which the wing is constrained against the lead body and a second unwrapped configuration is which the wing is unconstrained and allowed to extend outwardly. The wing can be biased to unwrap such that the wing tips change in angular position when viewed from the end, and in transverse extension when viewed from the top, but not in longitudinal position when viewed from the side. A pusher tube can be used to urge the lead from a delivery catheter, allowing the wing or wings to extend to urge a surface electrode toward the spinal cord, to maintain longitudinal position, and to be passively fixed over time. Leads according to the present invention can provide improved longitudinal stability after the lead electrode position has been properly fixed with respect to the spinal cord.