Electrode Lead Extraction Using Dilator and Trephine Dissection
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Solution Overview
Problem
Existing electrode leads used for spinal stabilization systems face challenges with dislodgement and fracture due to the complex anatomy of the lower back, particularly the thoracolumbar fascia and mobile muscles, leading to difficulties in safe removal and replacement.
Innovation Solution
A lead extraction system comprising a dilator and trephine is used to safely remove implanted electrode leads by collapsing fixation elements and cutting surrounding tissue, utilizing a sheath for stability and a trephine for tissue dissection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixation elements are used to anchor the electrode lead in tissue, then the lead stability is improved, but the difficulty of lead removal increases and tissue trauma occurs
Solution Approach 1:
The fixation element is divided into multiple segments that can independently collapse. When the dilator is advanced, each segment collapses separately, allowing the fixation element to detach from the tissue in a controlled manner, reducing removal difficulty while maintaining anchoring stability during use
Solution Approach 2:
The fixation element transitions from a static expanded state during implantation to a dynamic collapsed state during removal. The ability of the fixation element to change its configuration dynamically allows it to provide strong anchoring when needed and be easily removed when necessary, resolving the contradiction between stability and ease of removal
2Ease of operation
If the dilator is advanced to collapse fixation elements, then the lead removal is facilitated, but the risk of lead fracture increases
Solution Approach 1:
The dilator is designed with a gradual taper and smooth surface that progressively compresses the fixation element during advancement. This gradual compression prevents sudden stress concentration that could cause lead fracture, while still achieving complete collapse of the fixation element for safe removal
Solution Approach 2:
The application force on the fixation element is gradually increased as the dilator advances, changing the compression parameter progressively rather than abruptly. This controlled parameter change allows the fixation element to collapse safely without exceeding the lead's fracture threshold
3Reliability
If the trephine is used to cut surrounding tissue, then the extraction safety is improved, but the procedure complexity increases
Solution Approach 1:
The trephine is used to pre-cut a pathway in the tissue before the lead extraction. This preliminary action creates a controlled extraction path that prevents uncontrolled tissue tearing, improving safety while the modular design keeps the overall procedure manageable
Solution Approach 2:
The trephine acts as an intermediary tool that mediates between the extraction force and the tissue. It creates a controlled interface for tissue separation, improving extraction safety by preventing direct trauma while the systematic approach maintains procedural efficiency
Data Source
AI summary
Systems and methods are provided for extracting an implanted lead from a patient's body. The system may include a dilator and a trephine for extracting the electrode lead. A sheath may be included that is advanced over the proximal end of an electrode lead until the distal end of the sheath abuts a collar of the electrode lead coupled to proximal fixation elements. The dilator may be rotatably and axially advanced over the sheath until the distal end of the dilator collapses the proximal fixation elements within a lumen of the dilator. The trephine may then be rotatably and axially advanced over the dilator such that a cutting edge of the trephine cuts tissue surrounding distal fixation elements of the electrode lead to thereby dislodge the electrode lead.