Expandable Cannula with Segmented RF Electrode
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Solution Overview
Problem
Current surgical methods for cutting and resecting nerve and soft tissue, especially in minimally invasive procedures, face challenges such as difficulty in achieving precise dissection, high collateral thermal damage, and inefficient control of bleeding, leading to pain and tissue destruction, with existing electrosurgical devices causing indiscriminate tissue damage and obscuring visualization due to smoke generation.
Innovation Solution
A surgical device with an elongated shaft and retractable stylet that expands to enlarge holes in tissue, equipped with a cutting portion that can emit RF energy or pulsed plasma signals for precise cutting and tissue removal, allowing for controlled enlargement of tissue openings and minimizing collateral damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high power settings are used to initiate the cut in closed environment, then the current density at the cutting electrode is sufficient to initiate the cut, but thermal damage to the tissue increases and the procedure becomes painful
Solution Approach 1:
The electrode is divided into multiple segments along its length, with each segment capable of being independently activated. This segmentation allows the electrical current to be distributed across multiple smaller contact points rather than concentrated at a single point, thereby achieving sufficient current density for cutting while reducing the thermal load on any single tissue location.
Solution Approach 2:
The electrode delivers electrical current in a pulsed or intermittent manner rather than continuously. By applying high power settings periodically with intervals between pulses, the system accumulates sufficient energy for effective cutting while allowing thermal dissipation during the intervals, thus preventing excessive thermal damage and reducing pain.
2Reliability
If radio frequency energy is used to control bleeding by coagulating blood vessels, then bleeding is controlled effectively, but smoke is generated that obscures visualization and prolongs operative time
Solution Approach 1:
A fluid intermediary (such as irrigation fluid or smoke evacuation medium) is introduced between the RF energy source and the surgical field. This intermediary serves dual purposes: it acts as a heat sink to reduce thermal damage and smoke generation, while simultaneously maintaining a clear visual field by evaporating or carrying away smoke particles, thus preserving visualization without compromising hemostatic control.
3Productivity
If conventional monopolar high frequency electrosurgical devices are used to create voltage difference and electrical arc, then tissue cutting is achieved through rapid heating, but collateral tissue damage occurs and proper tissue function is lost
Solution Approach 1:
The electrode design incorporates varying properties along its length, with different segments having different electrical characteristics, contact surface areas, or activation thresholds. This allows the system to concentrate energy precisely at the intended cut site while minimizing energy dispersion to surrounding tissues, thereby achieving efficient cutting with reduced collateral damage.
Solution Approach 2:
The electrode system dynamically adjusts its electrical parameters (such as voltage, current, or pulse duration) based on real-time feedback from tissue impedance or power consumption measurements. This dynamic adjustment allows the system to maintain optimal cutting efficiency while preventing excessive energy delivery that would cause collateral thermal damage to surrounding tissues.
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
Enables efficient, precise, and controlled cutting and resection of nerve and soft tissue with reduced collateral damage and improved visualization, addressing the limitations of existing electrosurgical devices by providing fine dissection capabilities and effective hemostasis.
Implementation Method 1
The stylet is configured to retractably extend out of the elongated shaft so as to contact tissue
Implementation Method 2
Radio frequency energy is used in a wide range of surgical procedures because it provides efficient tissue resection and coagulation
Implementation Method 3
At the point of contact of the electric arcs with tissue, rapid tissue heating occurs due to high current density between the electrode and tissue
Implementation Method 4
rapid tissue heating occurs due to high current density between the electrode and tissue. This high current density causes cellular fluids to rapidly vaporize into steam
Implementation Method 5
Another method of controlling bleeding is through the use of heat. For example, some commercially available scalpels use direct heat to control bleeding
Implementation Method 6
Other commercially available scalpels use ultrasonic energy generally at 50 kHz to heat the tissue so as to coagulate severed blood vessels
Implementation Method 7
equipped with a cutting portion that can emit RF energy or pulsed plasma signals for precise cutting and tissue removal
Data Source
AI summary
A cutting device includes an elongated shaft that extends between a proximal end and a distal end. A distal arm extends from the distal end of the elongated shaft. The distal arm includes an inner surface defining a cavity and an outer surface defining a blunt tip. At least one proximal arm extends from the distal end of the elongated shaft at a position proximal to the distal arm. The at least one proximal arm having an inner surface defines a cavity including a cutting portion configured to cut tissue.