Self-Folding Paddle Lead Shape Memory Spinal Stimulation
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Solution Overview
Problem
Conventional laminotomy leads require a surgical procedure for implantation due to their size and physical characteristics, necessitating a partial laminectomy and vertebral tissue resection for access and positioning within the epidural space.
Innovation Solution
A self-folding paddle lead with a shape memory feature, comprising an intermediate metal layer and insulative polymer layers, which folds for insertion through a small profile and unfolds to expose electrodes for spinal tissue stimulation, eliminating the need for surgical implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional laminotomy leads are used, then electrode positioning stability and electrical field efficiency are improved, but surgical complexity and tissue damage increase due to required partial laminectomy
Solution Approach 1:
The paddle lead employs a shape memory alloy structure that dynamically changes its configuration from a compressed insertion state to an expanded operational state. The paddle is compressed during insertion through the laminectomy site, then automatically expands to its full paddle configuration once deployed, providing stable electrode positioning without requiring complex surgical procedures for positioning
Solution Approach 2:
The paddle lead structure allows the paddle to be nested within itself during insertion. The paddle is compressed into a compact configuration that fits within the insertion catheter, then expands outward to its full functional size after deployment, minimizing the surgical opening required while maintaining the full electrode array for stable positioning
2Use of energy by moving object
If conventional laminotomy leads are used, then electrical field efficiency is improved, but tissue displacement and damage increase during insertion and removal
Solution Approach 1:
The lead incorporates a shape memory alloy structure that dynamically transitions between compressed and expanded states. During insertion, the paddle is compressed to minimize tissue displacement. Once positioned, it automatically expands to provide the full electrical field coverage needed for effective stimulation, and can be compressed again for removal, minimizing tissue damage throughout the procedure
Solution Approach 2:
The shape memory alloy changes its physical parameters (shape, volume, configuration) in response to temperature or stress changes. This allows the paddle to transition from a compact low-profile insertion state to a full-size operational state, and back again for removal, reducing tissue displacement and damage while maintaining electrical field efficiency during operation
3Ease of operation
If percutaneous leads are used, then ease of insertion is improved, but electrode positioning stability and electrical field efficiency deteriorate
Solution Approach 1:
The lead combines the ease of percutaneous insertion with the stability of laminotomy leads by using a shape memory alloy structure. The paddle is inserted in a compressed state through a minimally invasive approach, then automatically expands to a stable full-size configuration once deployed, providing both easy insertion and reliable electrode positioning
Solution Approach 2:
The paddle structure is nested within itself during insertion, allowing it to pass through a small percutaneous opening. Once deployed, it expands to its full paddle configuration with multiple electrodes properly positioned, combining the minimally invasive insertion approach with the stable electrode array needed for effective electrical field delivery
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 insertion and removal of the paddle lead without partial laminectomy, maintaining electrode positioning stability and efficiency while reducing tissue displacement and potential damage during folding and unfolding.
Implementation Method 1
the paddle possesses shape memory to cause the paddle to assume a substantially planar orientation when the shape memory is in a relaxed state
Data Source
AI summary
In one embodiment, a medical lead comprises a lead body for conducting electrical pulses and a paddle. The paddle includes an intermediate metal layer, at least an insulative polymer backing layer, and an insulative polymer covering layer. The intermediate metal layer comprises a plurality of features defined by gaps in the metal material in the metal layer such that each feature is electrically isolated from each other feature, wherein each feature includes a respective connector element that is electrically coupled to at least one conductor within the lead body, wherein a portion of the insulative polymer covering layer is exposed above each feature to define a respective electrode for the corresponding feature. Also, the paddle possesses shape memory to cause the paddle to assume a substantially planar orientation when the shape memory is in a relaxed state.