Medical DC Current Generator Bipolar Implant Fragmentation
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Solution Overview
Problem
Existing medical direct current generators fail to securely fragment thin-walled and wire-shaped metallic implants due to rapid re-solidification of melted material, caused by high heat dissipation and loss of physical contact between electrodes and the implant, leading to incomplete cutting.
Innovation Solution
A medical direct current generator with a control device that maintains current flow after physical contact is lost, using a two-phase cutting process: a heating phase to melt the implant material and a cutting phase that sustains an electric arc to ensure separation is completed before re-solidification occurs, with adjustable parameters for different implant materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a single DC current pulse is applied to melt the implant material, then localized heating to melting point is achieved, but rapid re-solidification occurs due to high heat dissipation
Solution Approach 1:
The single DC current pulse is divided into multiple sequential pulses. The first pulse melts the implant material, and subsequent pulses maintain the temperature to prevent re-solidification. This segmentation of the heating process ensures the material remains in liquid state long enough for complete fragmentation.
Solution Approach 2:
The control device is pre-programmed with material-specific parameters (number of pulses, pulse duration, pulse interval) based on the implant material type. This preliminary configuration ensures optimal pulse parameters are applied automatically, preventing re-solidification before fragmentation is complete.
2Loss of energy
If the current pulse duration is minimized to reduce heat dissipation, then localized melting is improved, but the melted material re-solidifies before separation is completed
Solution Approach 1:
Instead of a single continuous or minimal pulse, the system applies periodic DC current pulses with specific intervals. The pulses are spaced to allow heat distribution within the melted zone while maintaining overall temperature above melting point, preventing re-solidification during the separation process.
Solution Approach 2:
The multiple pulse sequence ensures continuous heating action throughout the fragmentation process. Rather than a brief single pulse that allows cooling, the repeated pulses maintain thermal energy in the implant material, ensuring the melted state is sustained until separation is complete.
3Power
If high current density is applied through small contact area, then localized melting is achieved, but loss of physical contact occurs when melted material moves
Solution Approach 1:
The control device dynamically adjusts the current pulse parameters based on real-time feedback from voltage and current monitoring. When contact is lost (detected by voltage spike or current drop), the system automatically extends or repeats pulses to maintain heating, adapting to the dynamic state of the melted material.
Solution Approach 2:
The control device continuously monitors the electrical parameters (voltage, current) during pulse application. This feedback mechanism detects when physical contact is lost and triggers appropriate responses such as extending pulse duration or applying additional pulses, ensuring fragmentation completes even without sustained contact.
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
The solution effectively prevents re-solidification of the implant material, ensuring successful fragmentation by maintaining an electric arc for a predetermined time after contact loss, thereby improving the success rate of implant cutting and reducing tissue damage.
Implementation Method 1
The application of a single DC current pulse onto the OTSC clip material leads to very localized heating of a cross-section of the implant material (for example Nitinol) to its (well-known) melting point
Implementation Method 2
The control device is adapted to extend the current pulse until a predetermined time has passed since the loss of contact or to maintain a current flow through an electric arc
Data Source
AI summary
The present invention is directed to an endoscopic implant cutting and/or fragmenting apparatus of the bipolar type, operating on direct current, comprising an endoscope instrument having at least two opposing electrodes at its distal instrument head forming a cutting gap inbetween for receiving an electrically conductive implant or implant section to generate punctiform physical contact with the implant, and a DC-impulse generator connected to a control device adapted to generate a direct current in a pulsed way such that in a first phase of physical contact, the current pulse is adjusted to induce electric energy into the implant material being sufficient to melt the implant material exclusively in the area of the contact portion and in a second phase of physical noncontact, the current pulse is adjusted to generate an electric arc between at least one electrode and the melted implant material being sufficient to cut the melted implant material.