Microwave Electrosurgical Radiating Tip for Moving Organ Ablation
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Solution Overview
Problem
Conventional electrosurgical instruments face challenges in accurately locating and treating target tissue, especially in moving organs like the lung or thin-walled gastrointestinal tract, due to their design, which can lead to excessive bleeding and tissue damage during procedures like microwave ablation in highly vascularized regions.
Innovation Solution
An electrosurgical system with a small-diameter radiating tip (1.0 mm or less) that is extendible and guided through a surgical scoping device, combined with pulsed microwave energy delivery to minimize tissue damage and bleeding, utilizing a flexible coaxial cable and a distal needle tip configured as a half-wavelength transformer for efficient energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electrosurgical instruments are used for treating tissue in moving organs like lung or GI tract, then the treatment can be performed, but the instrument cannot be accurately located in the target site due to organ movement
Solution Approach 1:
The electrosurgical instrument is nested within a protective catheter that is inserted through an instrument channel of a surgical scoping device. The instrument can be extended from the catheter to reach target sites in moving organs while the catheter remains positioned in the instrument channel, allowing accurate localization despite organ movement.
2Object-affected harmful factors
If a small diameter radiating tip is used to minimize tissue damage and bleeding, then healthy tissue damage is reduced, but the instrument becomes more difficult to guide and position accurately
Solution Approach 1:
The instrument is segmented into a flexible coaxial cable for energy transmission and a separate rigid radiating tip portion with small outer diameter. The flexible cable provides ease of guidance and positioning, while the small-diameter tip minimizes tissue damage and bleeding at the treatment site.
3Productivity
If microwave energy is delivered continuously to ablate target tissue, then ablation effectiveness is improved, but the radiating tip overheats causing damage to healthy tissue
Solution Approach 1:
The electrosurgical generator delivers microwave energy in pulsed intervals rather than continuously. The controller activates the generator to emit microwave energy for specific time intervals, allowing the radiating tip to cool between pulses. This prevents overheating and damage to healthy tissue while maintaining effective ablation of target tissue.
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 system effectively ablates target tissue while reducing bleeding and minimizing damage to healthy tissue, facilitating precise treatment in challenging anatomical locations like the pancreas and liver by maintaining the radiating tip at an acceptable temperature through pulsed energy delivery.
Implementation Method 1
Water molecules have a permanent electric dipole moment, meaning that a charge imbalance exists across the molecule. This charge imbalance causes the molecules to move in response to the forces generated by application of a time varying electric field as the molecules rotate to align their electric dipole moment with the polarity of the applied field. At microwave frequencies, rapid molecular oscillations result in frictional heating and consequential dissipation of the field energy in the form of heat. This is known as dielectric heating.
Implementation Method 2
a flexible coaxial cable arranged to convey the microwave energy
Data Source
AI summary
An electrosurgical system for treating biological tissue that comprises: an electrosurgical generator to supply microwave energy; a surgical scoping device having a steerable insertion cord for insertion to a treatment site; and an electrosurgical instrument dimensioned to fit within an instrument channel that is located within the insertion cord. The electrosurgical instrument comprises: a flexible coaxial cable arranged to convey the microwave energy; and a radiating tip portion connected at an end of the coaxial cable and configured to receive microwave energy. The radiating tip portion comprises: a coaxial transmission line for conveying the microwave energy; and a needle tip mounted at an end of the proximal coaxial transmission line, wherein the electrosurgical instrument is slidable within the instrument channel to extend the needle tip beyond an end of the instrument channel to puncture biological tissue; the needle tip is arranged to deliver the microwave energy into biological tissue.