Electroactive Polymer Actuator for Surgical Stapler Articulation
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Solution Overview
Problem
Current circular stapling devices require a large force for actuation, which can exceed a surgeon's hand strength and lead to binding or malfunctions, and the force required varies throughout the firing stroke, affecting the flexibility and adjustability of the shaft.
Innovation Solution
The use of electroactive polymer actuators to drive staples and articulate the stapling apparatus, allowing for low-force actuation and articulation by delivering energy to move the staple applying assembly and anvil, and to pivotally adjust the stapling apparatus relative to the elongate shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hand-squeezed trigger is used to actuate the stapling apparatus, then the device can be operated manually, but the large force required to effect firing exceeds the surgeon's hand strength and can cause binding or malfunctions
Solution Approach 1:
The patent replaces the traditional mechanical spring-loaded actuator with an electroactive polymer (EAP) actuator that converts electrical energy directly into mechanical motion. This substitution eliminates the need for high manual squeezing forces while maintaining the ability to drive staples through tissue effectively.
Solution Approach 2:
The patent changes the actuation parameter from mechanical force (hand-squeezed trigger) to electrical stimulus (voltage applied to EAP). This parameter change allows for precise control of the actuation force and eliminates the limitation of human hand strength.
2Reliability
If the force required to fire the stapler is reduced, then operator fatigue is reduced and binding is prevented, but the ability to drive staples through tissue effectively may be compromised
Solution Approach 1:
The electroactive polymer actuator provides precisely controllable electrical stimulation that can be tuned to deliver the exact amount of force needed for reliable staple formation without excessive force that causes binding or operator fatigue.
Solution Approach 2:
The EAP actuator system allows for controlled delivery of energy to achieve consistent stapling forces throughout the firing stroke, preventing the force variations that lead to binding while maintaining effective staple driving capability.
3Adaptability or versatility
If a flexible shaft is used to allow curved insertion pathway, then the shaft can navigate curved pathways, but the transfer of force from handle to stapling apparatus interferes with the curved orientation and may cause straightening
Solution Approach 1:
The patent replaces the mechanical force transmission system with an electroactive polymer actuator located at the distal end of the shaft. This substitution eliminates the need to transfer mechanical force through the flexible shaft, thereby preserving the shaft's curved orientation without interference from actuation forces.
Solution Approach 2:
The actuation function is segmented from the shaft structure itself, with the EAP actuator being a separate component mounted on the distal portion of the shaft. This segmentation allows the shaft to maintain its flexible, curved configuration independently of the actuation mechanism.
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 consistent and efficient stapling with reduced operator fatigue, maintaining the flexibility and adjustability of the shaft by providing a controlled and consistent force throughout the stapling process.
Implementation Method 1
an electroactive polymer actuator coupled to the articulation joint and adapted to move the end effector about the articulation joint relative to the elongate shaft when energy is delivered to the electroactive polymer actuator
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A
AI summary
Methods and devices are provided for actuating and/or articulating a circular stapler. In one exemplary embodiment, a circular stapler is provided having an elongate shaft with a stapling apparatus coupled thereto. An electrically expandable and contractible actuator, such as an electroactive polymer actuator, can be used to pivotally or angularly adjust a position of the stapling apparatus relative to the elongate shaft by delivering energy to the electroactive polymer actuator. In another embodiment, an electroactive polymer actuator can be used to actuate the stapling apparatus, thereby driving one or more staples, preferably in a substantially curved pattern, into tissue. The actuator can alternatively or additionally drive a blade distally to cut tissue being stapled.