Surgical Instrument Torsion-Spring Drive for Closure Force Retention
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Solution Overview
Problem
Inflammation of the tonsils and adenoids impairs their ability to destroy bacteria, leading to recurrent infections and airway obstruction, necessitating procedures like tonsillectomy and adenoidectomy, which are often performed together to address persistent infections and enlarged tissue causing sleep disorders.
Innovation Solution
A surgical instrument with a housing, shaft, end effector assembly, movable handle, and drive assembly featuring a torsion spring mechanism that translates longitudinal movement into actuation of the end effector assembly, ensuring precise tissue grasping and energy application, with a torsion spring tensioning mechanism to maintain closure force and energy activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a surgical instrument is designed to provide precise tissue grasping and closure force, then the manufacturing precision and device complexity increase, but the reliability and ease of operation improve
Solution Approach 1:
The torsion spring mechanism is designed to automatically maintain closure force on the end effector assembly without requiring external adjustment or intervention. The spring self-regulates the force applied to the tissue, providing consistent closure force throughout the surgical procedure while eliminating the need for complex external control systems
Solution Approach 2:
The torsion spring mechanism allows for controlled change in mechanical parameters (force, position) of the end effector assembly. By designing the spring with specific mechanical properties, the system achieves precise control over closure force while maintaining a relatively simple overall device structure
2Ease of operation
If the drive assembly translates longitudinal movement into end effector actuation, then the ease of operation improves, but the device complexity increases
Solution Approach 1:
The drive assembly acts as an intermediary mechanism between the simple longitudinal movement of the movable handle and the complex actuation requirements of the end effector assembly. This intermediate mechanism translates and amplifies the user's input force while maintaining ease of operation, preventing the user from directly encountering the complexity of the actuation system
Solution Approach 2:
The drive assembly incorporates dynamic elements that allow smooth translation of longitudinal handle movement into end effector actuation. The mechanism adapts its mechanical advantage throughout the range of motion, providing consistent ease of operation while managing the complexity of the actuation process
3Reliability
If the torsion spring maintains closure force, then the reliability improves, but the loss of energy increases
Solution Approach 1:
The torsion spring provides periodic or sustained closure force maintenance throughout the surgical procedure. Rather than requiring continuous energy input, the spring stores energy during the closing action and releases it gradually to maintain closure force, reducing overall energy loss while ensuring reliable tissue grasping throughout the procedure
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
The instrument enables efficient grasping and treatment of tonsillar and adenoidal tissue, ensuring appropriate closure force and energy delivery, facilitating effective surgical procedures like tonsillectomy and adenoidectomy.
Implementation Method 1
The drive assembly includes a drive member and a torsion spring. The torsion spring includes a first leg and a second leg. The first leg is operably coupled to the movable handle and configured to translate longitudinally through the housing in response to movement of the movable handle relative to the housing. The second leg is operably coupled to the drive member and configured to translate longitudinally through the housing in cooperation with the first leg to thereby transfer longitudinal movement thereof into longitudinal movement of the drive member
Implementation Method 2
The second leg is configured to remain in fixed position, thereby tensioning the torsion spring and retaining the drive member in fixed position, in response to longitudinal movement of the first leg when the force acting on the drive member is equal to or exceeds the threshold force
Data Source
AI summary
A surgical instrument includes a housing, a shaft extending therefrom, an end effector assembly supported by the shaft, a movable handle, and a drive assembly. The drive assembly includes a translatable drive member for actuating the end effector assembly, and a torsion spring including first and second legs. The first leg is configured to translate through the housing in response to movement of the movable handle relative to the housing. The second leg is configured to translate through the housing in cooperation with the first leg to move the drive member longitudinally when a force acting on the drive member is less than a threshold force, and to remain in fixed position, thereby tensioning the torsion spring and retaining the drive member in fixed position when the force acting on the drive member is equal to or exceeds the threshold force.