Electrosurgical Forceps Near-Over-Center Linkage for VATS
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Solution Overview
Problem
In minimally-invasive thoracic surgery, such as Video Assisted Thoracoscopic Surgery (VATS), existing electrosurgical forceps face challenges in maneuverability and tissue handling due to limited access and space within the thoracic cavity, requiring instruments that can effectively treat and cut tissue with reduced force and precision.
Innovation Solution
The design of an electrosurgical forceps with an elongated shaft, a handle assembly, a drive bar, and an end effector assembly that includes pivotably coupled jaw members, where the movable handle's near-over-center position reduces the force required to maintain the closed position, allowing for efficient tissue grasping and cutting, and an activation assembly for energy supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional electrosurgical forceps are used in VATS procedures, then tissue treatment and cutting can be performed, but the force required to maintain the closed position is excessive and maneuverability is limited due to confined intercostal space access
Solution Approach 1:
The forceps incorporates a dynamic linkage mechanism with a movable pivot pin that transitions between over-center and near-over-center positions. This dynamic positioning allows the mechanism to shift from a high-force locking state to a lower-force operational state, enabling easier manipulation in confined thoracic spaces while maintaining effective tissue grasping capability
Solution Approach 2:
The invention changes the geometric parameter of the linkage mechanism by moving the pivot pin from an over-center position to a near-over-center position. This parameter change reduces the mechanical advantage ratio, thereby reducing the force required to maintain the closed position while still achieving effective tissue clamping for electrosurgical procedures
2Object-affected harmful factors
If access port is placed within intercostal space to minimize invasiveness, then patient trauma and recovery time are reduced, but maneuverability within thoracic cavity is limited
Solution Approach 1:
The forceps is designed with segmented, articulated components including movable jaw members and a flexible linkage system. This segmentation allows the distal end of the instrument to navigate the confined intercostal space and reach deep into the thoracic cavity, maintaining minimal invasiveness while improving maneuverability at the working end
Solution Approach 2:
The linkage mechanism incorporates multi-dimensional movement capabilities with pivot pins that can move in multiple planes. This allows the forceps to navigate the complex three-dimensional geometry of the intercostal space and thoracic cavity, converting the constraint of limited access into effective positioning capability through spatial manipulation
3Reliability
If electrosurgical forceps are used to treat and cut tissue in VATS, then lung resection can be performed with reduced bleeding, but the force required to maintain closed position complicates the procedure
Solution Approach 1:
The linkage mechanism is designed to automatically transition between over-center and near-over-center positions based on the operational requirements. The mechanism self-regulates the force requirements through its geometric design, eliminating the need for external force application adjustments and simplifying the overall procedure despite the complex internal mechanics
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
Facilitates precise and efficient tissue treatment and cutting in confined spaces, reducing the force needed to maintain the closed position and enhancing maneuverability, thereby improving the effectiveness of VATS procedures like lung resection.
Implementation Method 1
The movable handle, more specifically, is pivotably coupled to the drive bar via a first pivot pin. The first pivot pin is aligned on the longitudinal axis. The linkage includes a first end portion and a second end portion. The first end portion of the linkage is pivotably coupled to the movable handle via a second pivot pin, while the second end portion of the linkage is pivotably coupled to the elongated shaft via a third pivot pin. In the closed position of the movable handle, the second pivot pin is disposed in a near-over-center position relative to the longitudinal axis to reduce a force necessary to maintain the movable handle in the closed position.
Implementation Method 2
Electrosurgical forceps utilize both mechanical clamping action and energy to treat, e.g., coagulate, cauterize, and/or seal, tissue.
Implementation Method 3
Electrosurgical forceps utilize both mechanical clamping action and energy to treat, e.g., coagulate, cauterize, and/or seal, tissue.
Data Source
AI summary
A surgical instrument includes a shaft defining an axis, an end effector coupled to a distal portion thereof, a fixed handle coupled to a proximal portion thereof, a drive bar, a movable handle, and a linkage. The drive bar is disposed within the shaft and operably coupled to the end effector. The movable handle is movable relative to the fixed handle between open and closed positions and is coupled to the drive bar via a first pin on the axis. The linkage includes a first end portion coupled to the movable handle via a second pin and a second end portion coupled to the shaft via a third pin on the axis. In the closed position of the movable handle, the second pin is disposed in a near-over-center position relative to the axis to reduce a force necessary to maintain the movable handle in the closed position.