Capacitive Finger Control for Ultrasonic Surgical Handpiece
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Solution Overview
Problem
Conventional ultrasonic surgical devices face challenges such as foot pedal dependency, lack of sensory feedback, and unintentional activation risks during surgical procedures, which can lead to decreased precision and increased surgeon fatigue.
Innovation Solution
The development of an ultrasonic surgical instrument with a handpiece that incorporates capacitive and resistive sensing technologies for intuitive finger-activated control, providing tactile feedback and reducing the need for a foot pedal, while ensuring intentional activation through capacitive switch differentiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If foot pedal is used to activate ultrasonic energy, then surgeon can control activation from a distance, but surgeon loses focus on surgical field and experiences leg fatigue
Solution Approach 1:
The foot pedal activation mechanism is extracted and replaced with a finger-actuated switch located on the handpiece. This removes the need for the surgeon to move their foot away from the surgical field, allowing continuous visual focus on the surgical site while maintaining activation control through the integrated finger switch.
Solution Approach 2:
A capacitive switch with haptic feedback serves as an intermediary control mechanism between the surgeon's intent and the ultrasonic activation. The switch provides tactile confirmation of activation status, allowing the surgeon to maintain awareness of device state without visual distraction from the surgical field.
2Extent of automation
If conventional switch is used for activation, then device can be activated, but unintentional activation may occur
Solution Approach 1:
The capacitive switch incorporates haptic feedback that provides tactile confirmation when activation is detected. This feedback mechanism allows the surgeon to verify intentional activation through touch, reducing unintentional activation while maintaining automated control functionality.
Solution Approach 2:
The switch utilizes changes in capacitive parameters (electrical properties) when a finger approaches or contacts the switch surface. This parameter-based detection method provides more precise control compared to conventional mechanical switches, enabling differentiation between intentional and unintentional contact through controlled electrical field changes.
3Device complexity
If no sensory feedback is provided, then device structure remains simple, but surgeon cannot confirm activation status
Solution Approach 1:
The handpiece incorporates a vibration motor that provides tactile feedback to the surgeon's hand when ultrasonic activation occurs. This mechanical vibration feedback confirms activation status without requiring visual attention, maintaining simple device architecture while providing essential status information through the sense of touch.
Solution Approach 2:
Multiple feedback mechanisms (haptic switch confirmation and vibration motor) work together to provide comprehensive activation status information. The feedback loop closes the information gap between activation command and activation state, allowing the surgeon to maintain awareness of device status through tactile senses rather than visual monitoring.
4Manufacturing precision
If thumbwheel and release button are used to adjust blade angle, then precise adjustment is possible, but operation becomes complex and time-consuming
Solution Approach 1:
The blade angle adjustment function is merged with the main body of the handpiece, allowing the surgeon to rotate the entire device to adjust the blade angle. This eliminates the need for separate thumbwheels and release buttons, providing precise angular adjustment through natural wrist rotation while simplifying the operational sequence.
Solution Approach 2:
Instead of adjusting the blade angle through complex mechanical mechanisms (thumbwheel and release button), the invention inverts the approach by allowing the surgeon to rotate the entire handpiece body. This inversion of the adjustment mechanism transforms a multi-step mechanical operation into a simple rotational movement, maintaining precision while dramatically improving ease of operation.
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 surgical precision and reduces fatigue by allowing direct finger control of ultrasonic energy, minimizing unintentional activation, and improving workflow during procedures.
Implementation Method 1
a capacitive sensor configured to detect when the finger is in proximity to or contacting the activation surface
Implementation Method 2
a resistive sensor configured to detect when the finger is contacting the activation surface
Implementation Method 3
Vibrating at high frequencies (e.g., 55,500 times per second), the ultrasonic blade may denature protein in the tissue to form a sticky coagulum
Data Source
AI summary
An exemplary surgical instrument comprises a handpiece, an end effector, and an activation and control feature that is operable to selectively activate an end effector and select an energy level for the end effector. One version of the activation and control feature includes a “floating” button feature where activation and control is accomplished based on the displacement of the button from a home position. In some versions the activation and control feature is sealed within the handpiece, but controllable by the user's touch with the handpiece. The sealed configuration can allow the handpiece to be sterilizable, e.g., using steam sterilization. The activation and control feature may comprise capacitive switches, resistive sensors, resonant cavity switching technology, infrared sensing technology, technology that uses a resonant standing wave on a surface that is perturbed by the presence of a finger, and/or any other suitable type of technology.