Bronchoscopic Lung Tumor Ablation Using Conductive Hypertonic Saline
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Solution Overview
Problem
Current methods for bronchoscopic ablation of lung tumors face challenges due to high tissue impedance, air volume, and the difficulty of navigating ablation electrodes to peripheral tumors, limiting the effectiveness of radiofrequency (RF) energy delivery.
Innovation Solution
The use of conductive fluids like hypertonic saline to reduce tissue impedance, combined with RF ablation energy, and techniques to collapse lung tissue volume to enhance electrode-tissue contact, allowing for more efficient RF energy delivery through a system that includes a flow regulator and sensors for real-time control of energy and fluid delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If percutaneous RF ablation with needle electrode is used, then immediate technical success rate is over 95%, but major complication rate is 8 to 12% and requires CT guidance
Solution Approach 1:
A conductive fluid (such as saline solution) is introduced as an intermediary between the RF electrode and the lung tumor tissue. This fluid mediates the energy transfer by reducing electrical impedance at the interface, allowing more efficient RF energy delivery to the tumor while reducing the risk of complications such as pneumothorax and tissue damage
2Length of moving object
If bronchoscopic ablation is performed through working channel of bronchoscope, then access to peripheral tumors is enabled, but ablation electrode navigation difficulty increases and ablation volume is limited
Solution Approach 1:
The ablation system is segmented into modular components: a navigable bronchoscope for access, a separate catheter for electrode delivery, and a deployable electrode array. This segmentation allows the bronchoscope to navigate to peripheral tumors while the electrode catheter can be independently positioned and deployed at the target site, reducing navigation complexity
Solution Approach 2:
The ablation electrode catheter is nested within the bronchoscope's working channel during navigation. Once the bronchoscope reaches the peripheral tumor location, the nested catheter is deployed outward from the bronchoscope to position the electrode array at the tumor site, enabling access to distant locations while maintaining operational simplicity
3Reliability
If RF ablation is performed in lung tissue with air and blood perfusion, then treatment of lung tumors is achieved, but tissue impedance increases and cooling effect reduces ablation effectiveness
Solution Approach 1:
A conductive fluid is introduced as an intermediary substance between the RF electrode and the lung tissue. This fluid displaces air at the electrode-tissue interface, reducing electrical impedance and improving current flow into the tissue. The fluid also creates a more stable thermal environment by reducing evaporative cooling, thereby enhancing ablation effectiveness
Solution Approach 2:
The electrical and thermal parameters of the treatment environment are changed by introducing conductive fluid. The fluid alters the electrical conductivity of the interface region, reducing impedance from high (air-filled) to low (fluid-filled). It also modifies thermal parameters by reducing evaporative heat loss and improving thermal coupling between electrode and tissue
4Reliability
If microwave energy is used instead of RF, then air volume interference is reduced, but simplicity and efficiency of RF heating is lost
Solution Approach 1:
A conductive fluid is introduced as an intermediary that eliminates the need for microwave energy by providing a conductive pathway for RF energy. The fluid displaces air in the treatment zone, allowing standard RF systems to function effectively without requiring complex microwave generation and delivery equipment, thus maintaining system simplicity while achieving reliable energy delivery
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
This approach improves the effectiveness of RF energy delivery, increasing the size of ablation zones and reducing complications, enabling more precise and efficient treatment of lung tumors, particularly those in harder-to-reach peripheral locations.
Implementation Method 1
delivering conductive fluid (e.g. HTS) into the airway through the endobronchial ablation catheter to reduce tissue impedance and increase the effective RF energy delivery electrode size
Implementation Method 2
Ablating the tumor with RF ablation energy using monopolar, multiple monopolar, bipolar, multi-polar and multiphasic RF configurations
Implementation Method 3
Collapsing, compressing, air-volume reducing or partially collapsing a portion of a lung comprising a tumor to ablate the tumor
Data Source
AI summary
A method to treat a human patient including: advancing a catheter through a natural airway of the patient and positioning a distal portion of the catheter in the natural airway of a lung of the patient to a target region in the lung, injecting a conductive hypertonic saline solution having a concentration of at least 5% of sodium chloride by weight/volume from the distal portion of the catheter into the target region; delivering energy from the distal portion into the hypertonic saline solution in the target region, wherein the energy heats the hypertonic saline solution in the target region; ablating the target region with the heated conductive hypertonic saline solution, sensing electric impedance or electric conductivity of the target region during the delivery of the energy, and controlling the rate or a bolus of the hypertonic saline solution injected into the target region based on the electric impedance or the electric conductivity.