Ultrasonic Surgical End Effector Feedback for Tissue Heating Control
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Solution Overview
Problem
Ultrasonic surgical instruments face limitations in their ability to react to tissue conditions, leading to inconsistent performance due to heating issues and limited flexibility, especially in laparoscopic and endoscopic applications, and lack of real-time feedback on tissue interaction.
Innovation Solution
A surgical device with a transducer, end effector, generator, and control circuit that detects tissue contact and adjusts vibration frequency, calculates collagen denaturation, and provides real-time feedback on tissue coagulation, using a clamping mechanism to apply pressure and a central member with radial mode transducers for enhanced flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If ultrasonic vibration is transmitted to tissue at high energy levels, then cutting and coagulation effectiveness is improved, but tissue heating increases leading to inconsistent performance
Solution Approach 1:
The control circuit monitors the vibration frequency of the end effector and adjusts the current amplitude of the electrical signal to maintain consistent ultrasonic energy transmission despite tissue heating. The system detects frequency changes caused by temperature effects and compensates in real-time to maintain cutting and coagulation effectiveness.
Solution Approach 2:
The system dynamically adjusts electrical parameters (current amplitude, frequency) based on detected vibration frequency changes. By monitoring and responding to frequency drift caused by heating, the control circuit modifies operating parameters to maintain consistent ultrasonic energy delivery and performance.
2Device complexity
If a single element end effector is used, then device simplicity is improved, but ability to apply blade-to-tissue pressure on soft tissue is reduced
Solution Approach 1:
The patent combines a single ultrasonic blade element with a separate clamping mechanism that applies pressure to the tissue. This merging of the ultrasonic cutting element with a mechanical clamping system enables effective pressure application on soft tissue while maintaining the simplicity of the ultrasonic generation system.
3Device complexity
If only the tip of the end effector is ultrasonically active, then transducer-to-end effector energy transmission is simplified, but flexibility and articulation capability are limited
Solution Approach 1:
The end effector is segmented into an ultrasonic waveguide portion and a flexible articulation portion. The waveguide transmits ultrasonic energy to the active tip, while the flexible portion enables articulation and adaptation to different surgical sites. This segmentation allows the system to maintain simple transducer coupling while gaining flexibility.
Solution Approach 2:
The end effector incorporates flexible materials and thin-walled structures that enable articulation and bending while maintaining ultrasonic energy transmission. The flexible construction allows the end effector to navigate complex anatomical pathways and adapt to different surgical configurations.
4Manufacturing precision
If ultrasonic frequency is increased, then cutting precision is improved, but sensitivity to frequency changes from tissue contact increases
Solution Approach 1:
The control circuit continuously monitors the vibration frequency of the end effector and provides feedback to the generator. When frequency changes are detected (indicating tissue contact or heating), the system adjusts the electrical signal parameters to maintain the target ultrasonic frequency, ensuring consistent cutting precision despite environmental variations.
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
Enhances the ability of ultrasonic instruments to provide consistent cutting and coagulation by adapting to tissue conditions, improving flexibility and providing real-time feedback for better surgical outcomes.
Implementation Method 1
The transducer may be constructed of one or more piezoelectric or magnetostrictive elements in the instrument hand piece
Implementation Method 2
The transducer may be constructed of one or more piezoelectric or magnetostrictive elements in the instrument hand piece
Implementation Method 3
Ultrasonic vibrations, when transmitted to organic tissue at suitable energy levels and using a suitable end effector, may be used to cut, dissect, elevate or cauterize tissue
Implementation Method 4
Activating or exciting the end effector (e.g., cutting blade) of such instruments at ultrasonic frequencies induces longitudinal vibratory movement that generates localized heat within adjacent tissue
Implementation Method 5
The waveguides and end effectors are designed to resonate at the same frequency as the transducer
Data Source
AI summary
A surgical device. The surgical device may comprise a transducer, an end effector, a generator and a control circuit. The transducer may be configured to provide vibrations. The end effector may be coupled to the transducer and may extend from the transducer along the longitudinal axis. The generator may provide an electrical signal to the transducer. Also, the control circuit may modify a current amplitude of the electrical signal in response to a change in a vibration frequency of the end effector. Accordingly to various embodiments, the control circuit may detect a first contribution to a vibration frequency of the end effector, the first contribution originating from tissue in contact with the end effector. Also, according to various embodiments, the control circuit may indicate a change in a vibration frequency of the end effector.