Torsion Spring Drive Assembly for Surgical Tissue Grasping
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Solution Overview
Problem
Current surgical instruments for tonsillectomy and adenoidectomy lack efficient mechanisms for grasping and treating tissue, particularly in maintaining consistent closure pressure and energy application, which can lead to incomplete tissue removal and increased procedural complexity.
Innovation Solution
A surgical instrument featuring a drive assembly with a torsion spring and movable handle that translates longitudinal movement into longitudinal movement of the end effector assembly, allowing for precise tissue grasping and energy application, with a mechanism to maintain closure pressure and tension the spring for consistent operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a surgical instrument uses a simple mechanical linkage for actuating the end effector, then the device complexity is reduced, but the consistency of closure pressure and precision of tissue grasping deteriorates
Solution Approach 1:
The torsion spring provides continuous force feedback to the drive member, automatically adjusting the closure pressure based on tissue resistance. As the movable handle is squeezed, the torsion spring tensions and delivers consistent closing force to the end effector, ensuring reliable tissue grasping without over-compression
Solution Approach 2:
The torsion spring changes its mechanical parameter (torque) in response to handle displacement, transforming the operator's squeezing motion into controlled closing force. This parameter change ensures that the closure pressure remains consistent throughout the grasping operation
2Ease of operation
If the drive member translates freely through the shaft, then the ease of operation is improved, but the control over end effector actuation and energy application deteriorates
Solution Approach 1:
The drive assembly transitions from a static linkage to a dynamic system where the torsion spring continuously adjusts the force transmission. The drive member moves smoothly through the shaft while the torsion spring dynamically controls the actuation, providing both ease of operation and reliable control
Solution Approach 2:
The torsion spring automatically tensions and releases the drive member without requiring additional control mechanisms. The spring self-regulates the force application to the end effector, ensuring reliable actuation control while maintaining smooth handle operation
3Device complexity
If the surgical instrument uses a fixed mechanism for tissue grasping, then the device complexity is reduced, but the adaptability to different tissue types and positions deteriorates
Solution Approach 1:
The end effector assembly is made dynamic through the torsion spring mechanism, allowing it to adapt its closing force to different tissue types and positions. The movable handle enables the end effector to adjust to various anatomical configurations while maintaining secure grasping
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 ensures consistent closure pressure and efficient energy delivery to tissue, enhancing the precision and effectiveness of tonsillectomy and adenoidectomy procedures by maintaining tension and facilitating smooth transitions between grasping and treating positions.
Implementation Method 1
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.