Temporary Nerve Stimulation Lead with Shape Memory Retention
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Solution Overview
Problem
Current nerve stimulation therapies often require invasive and costly procedures for chronic treatment, lacking a minimally invasive, inexpensive, and easily removable option for temporary or trial stimulation to assess efficacy before committing to a permanent system.
Innovation Solution
A lead design featuring metallic traces sandwiched between polymer layers, forming a ribbon that fits within a small diameter needle, with exposed ends for electrodes and contacts, allowing for minimal invasive implantation, retention in tissue after needle removal, and easy removal, suitable for temporary stimulation of peripheral and cranial nerves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a chronic implant is used for long-term nerve stimulation, then long-term pain relief is achieved, but the procedure becomes invasive and costly
Solution Approach 1:
The lead is segmented into a distal portion with electrodes for nerve stimulation and a proximal portion with electrical contacts for connection to the stimulator. This segmentation allows the lead to function as a temporary, minimally invasive device that can be easily implanted and removed, avoiding the complexity of chronic implant procedures while providing sufficient duration for trial stimulation
Solution Approach 2:
The lead is designed as a disposable, temporary device intended for trial stimulation rather than permanent implantation. This approach reduces the complexity and cost of the implantation procedure compared to chronic implants, while the lead remains functional for the required trial period. After use, the lead is removed and discarded, eliminating the need for complex retrieval or revision procedures
2Ease of operation
If a temporary lead is designed for minimal invasive implantation, then ease of implantation is improved, but retention in tissue may be compromised
Solution Approach 1:
The lead incorporates a shape memory alloy that dynamically changes its shape in response to temperature changes. During implantation, the lead is inserted in a constrained state through a needle. After implantation, body heat causes the shape memory alloy to activate, causing the lead to expand and engage fixation features that secure it to the nerve. This dynamic shape change provides reliable retention while maintaining minimal invasiveness during the implantation procedure
Solution Approach 2:
The lead utilizes changes in physical parameters, specifically temperature, to trigger the shape memory effect. The lead is implanted at room temperature in a compact form, then body temperature causes it to transform into its final configuration with engagement features. This parameter change enables the lead to transition from an easy-to-implant state to a securely-retained state without requiring complex implantation procedures
3Ease of operation
If a trial stimulation system is designed to be easily removable, then ease of removal is improved, but secure engagement during trial may be compromised
Solution Approach 1:
The shape memory alloy provides dynamic engagement that is secure during trial stimulation but reversible when needed. The lead expands and locks onto the nerve using body heat during the trial period, providing reliable retention. For removal, the lead can be cooled or mechanically manipulated to reverse the shape memory effect, causing it to contract and release from the nerve. This dynamic behavior provides both secure engagement during use and ease of removal when needed
Solution Approach 2:
The lead is designed for periodic use during trial stimulation periods. During each trial period, the lead provides secure engagement through the shape memory effect. Between trials or at the end of the trial, the lead is removed. This periodic engagement and disengagement cycle allows the lead to provide reliable retention when needed while maintaining ease of removal for trial purposes
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 a minimally invasive, cost-effective, and easily removable temporary nerve stimulation solution that can be used for trial purposes, providing effective and secure tissue engagement without the need for complex implantation procedures.
Implementation Method 1
The lead ribbon may be wrapped around the stylet in a helical configuration such that upon removal of the stylet, the lead ribbon springs open to engage surrounding tissue
Data Source
AI summary
Apparatus and associated methods relate to a lead that includes metallic traces sandwiched between layers of polymers to form a ribbon (e.g., similar to a flex circuit). In an illustrative example, areas on both ends of the traces may be exposed, forming stimulation electrodes on one end and electrical contacts on the other. The ribbon may be formed such that it fits down a small diameter needle. When the needle is removed, the formed ribbon may relax and engage the tissue providing a means of retention. The lead may advantageously: (1) be minimally invasive to implant, (2) be inexpensive, (3) stay in place a temporary/trial medical procedure setting, and (4) be easy to remove.