Keyed Stimulator Anchor Structure to Prevent SCS Lead Migration
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Solution Overview
Problem
Current spinal cord stimulation (SCS) devices suffer from migration or movement of the electrical stimulator due to the smooth outer body surface design, leading to reduced therapeutic efficacy, increased risk of infection, and the need for revisionary surgeries.
Innovation Solution
An anchor with a keyed outer surface and complementary retaining cavity, combined with a stimulating member having a keyed shape, secures the stimulator in place using sutures through retaining channels, preventing migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a smooth outer body surface is used for the electrical stimulator, then the device is easier to implant and has simpler manufacturing, but the stimulator migrates or moves from the desired treatment site
Solution Approach 1:
The anchor features a non-smooth outer body surface with protrusions that create retaining channels, providing localized friction and mechanical interlocking at the tissue interface while maintaining a smooth surface elsewhere for ease of implantation. This local quality change prevents stimulator migration without complicating overall manufacturing.
Solution Approach 2:
The anchor's outer body surface includes asymmetric protrusions that create directional retaining channels, providing mechanical interlocking that resists migration forces. The asymmetric geometry creates effective friction-based retention while maintaining relatively simple manufacturing processes.
2Reliability
If sutures are used to secure the electrical stimulator, then the stimulator can be retained in place, but the friction between suture and smooth surface is reduced, increasing migration risk
Solution Approach 1:
The anchor incorporates localized non-smooth features (protrusions forming retaining channels) at the suture contact regions, creating high-friction zones that enhance suture retention. The smooth surface regions remain unchanged for ease of implantation, while the localized texture changes provide the necessary friction force to prevent migration.
3Reliability
If the anchor has a non-smooth outer body surface with retaining channels, then migration is prevented through increased friction, but the manufacturing complexity increases
Solution Approach 1:
The anchor is formed from flexible memory polymer material that can be molded into the final shape with integrated non-smooth features. This allows the retaining channels and protrusions to be created directly during forming rather than requiring post-manufacturing operations, reducing manufacturing complexity while maintaining migration prevention functionality.
Solution Approach 2:
The anchor utilizes memory polymer composite material that combines flexibility with shape retention properties. This material enables the creation of complex non-smooth surface geometries with retaining channels while maintaining manufacturability through direct molding or forming processes.
Data Source
AI summary
An electrotherapeutic device includes a stimulation member and an anchor to retain the stimulation member at the treatment site of implantation. The stimulating member and the anchor have surfaces that are “keyed” to each other, such that when the stimulating member is inserted in the anchor, the stimulating member is resistant to moving relative to the anchor. The anchor also includes one or more retaining channels, which are configured to receive sutures therein that are used to secure the anchor to the treatment site of implantation, which prevent the anchor from moving or migrating relative to the treatment site.