Epidural Paddle Lead With Shape Memory Alloy Frame
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Solution Overview
Problem
Current epidural stimulation leads, particularly percutaneous and laminotomy leads, face challenges in invasive procedures and stability during implantation, with percutaneous leads being less invasive but less stable, and laminotomy leads requiring surgical procedures for implantation.
Innovation Solution
A flexible paddle-style lead with a rigid frame and elastic material that can expand for insertion and resume shape for optimal electrode positioning, allowing for percutaneous implantation without the need for partial laminectomy, providing stability and versatility in electrode placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If percutaneous leads are used, then the implantation procedure is less invasive, but the stability of the lead during implantation deteriorates
Solution Approach 1:
The lead incorporates a shape memory alloy frame that can dynamically change its mechanical properties. During implantation, the frame is in a compressed, flexible state that allows percutaneous insertion through small incisions. Once deployed, the frame transitions to an expanded, rigid state that provides stable support for the electrodes, thus resolving the contradiction between ease of insertion and implantation stability.
Solution Approach 2:
The lead utilizes phase transition of shape memory alloy to change its physical parameters (rigidity, shape) between implantation and operational states. The alloy transitions from austenite phase (rigid) during manufacturing to martensite phase (flexible) during compression for insertion, then returns to austenite phase (rigid) after deployment, enabling both minimally invasive insertion and stable positioning.
2Reliability
If laminotomy leads are used, then the stability and positioning of electrodes is improved, but the implantation procedure requires surgical intervention
Solution Approach 1:
The lead design features a nested structure where the electrode array is contained within a collapsible frame that fits inside the introducer sheath during insertion. The frame and electrodes are nested together in a compact configuration that allows passage through small percutaneous incisions, then expand to their functional configuration after deployment, eliminating the need for open surgical procedures.
Solution Approach 2:
The lead transitions from a static, rigid structure requiring surgical implantation to a dynamic structure that changes form during implantation. The shape memory alloy frame dynamically adjusts its rigidity and shape, being flexible during insertion and rigid during operation, thereby enabling percutaneous implantation while maintaining the stability and positioning accuracy previously only achievable with surgical approaches.
3Reliability
If the lead structure is made rigid for stability, then the ease of insertion through percutaneous approach deteriorates
Solution Approach 1:
The shape memory alloy frame undergoes parameter changes in its mechanical properties through phase transitions. During compression for insertion, the alloy transforms to a flexible state with lower rigidity, enabling percutaneous passage. After deployment, it transitions to a rigid state with higher rigidity that ensures stable electrode positioning, thus resolving the contradiction between ease of insertion and positioning stability.
Solution Approach 2:
The lead structure is designed to be dynamic rather than static, with the frame's rigidity being adjustable based on the implantation stage. The frame is flexible during insertion to facilitate percutaneous approach, then becomes rigid after deployment to maintain electrode positioning, effectively decoupling the requirements for ease of insertion and stability that would otherwise be conflicting in a static structure.
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
Enables minimally invasive implantation of epidural stimulation leads with improved stability and positioning of electrodes, reducing the risks associated with surgical procedures while maintaining effective therapeutic delivery.
Implementation Method 1
elastic material disposed across an interior surface area defined by the frame, wherein a plurality of electrodes and a plurality of electrical traces are provided on the elastic material, wherein the plurality of electrical traces comprises a plurality of alternating curves that elongate when the elastic material is stretched
Data Source
AI summary
In one embodiment, a paddle-style lead for implantation in the epidural space through an insertion tool, the paddle-style lead comprises: a paddle structure that comprises: (i) a frame of rigid material, the frame comprising a spring member adapted to bias the frame to assume a first width and a first length, the frame being adapted to elongate to assume a second width and a second length under application of a compressive force; and (ii) elastic material disposed across an interior surface area defined the frame, wherein a plurality of electrodes and a plurality of electrical traces are provided on the elastic material, wherein the plurality of electrical traces are electrically coupled to a plurality of lead conductors and the plurality of electrodes; wherein the plurality of electrical traces comprises a plurality of alternating curves that elongate when the elastic material is stretched.