Bipolar Forceps with Four-Bar Linkage for Consistent Vessel Sealing
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Solution Overview
Problem
Current electrosurgical instruments face challenges in consistently sealing larger blood vessels during endoscopic procedures due to difficulties in controlling closure pressure and maintaining uniform tissue sealing, leading to ineffective or non-uniform seals, and require a method to accurately measure and ensure closure pressure within a specific range for effective vessel sealing.
Innovation Solution
A bipolar endoscopic forceps design with a four-bar mechanical linkage and a blade guide that includes a knife channel and stop members to control the distance between electrodes, facilitating consistent closure pressure and precise tissue sealing, while also allowing for multiple orientations to accommodate various surgical positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard electrosurgical techniques are used to seal larger vessels, then the vessel sealing may be ineffective or non-uniform, but increasing closure force may cause the electrically conductive surfaces to touch and short circuit
Solution Approach 1:
The patent introduces a compressible resilient member (spring) as an intermediary between the actuator and the jaw members. This spring mediates the force transmission, providing progressive closure force that maintains consistent pressure on the vessel without causing the electrically conductive surfaces to touch and short circuit, while still achieving effective vessel sealing
Solution Approach 2:
The patent changes the mechanical parameter of closure force from a direct rigid transmission to a progressive elastic transmission through the resilient member. This parameter change allows the closure force to adapt to the vessel thickness and maintain optimal pressure within the range of 3-16 kg/cm², preventing short circuits while ensuring reliable sealing
2Reliability
If larger vessels are sealed using electrosurgery, then appropriate electrosurgical power curve and large closure force are required, but this increases the risk of metal pins shearing due to large forces
Solution Approach 1:
The resilient member acts as a force-distributing intermediary that reduces peak loads on mechanical components. By distributing the closure force progressively through the spring mechanism, the patent prevents metal pins from shearing under large forces while maintaining the necessary closure force for large vessel sealing
Solution Approach 2:
The compressible resilient member provides beforehand cushioning by absorbing and distributing mechanical stresses before they reach the metal pins. This pre-cushioning effect protects the mechanical components from excessive forces during the sealing of large vessels
3Manufacturing precision
If manual control of closure pressure is used, then the success of sealing depends on surgeon skill, but consistent and uniform sealing pressure is difficult to achieve
Solution Approach 1:
The resilient member creates a self-regulating system that automatically maintains consistent closure pressure. The spring's elastic properties provide inherent feedback control, allowing the instrument to self-adjust and maintain optimal pressure without requiring constant surgeon intervention or high skill level for pressure control
4Manufacturing precision
If the gap distance between electrodes is not controlled, then effective sealing of smaller vessels is difficult, but the chances of surfaces touching increases as vessels become smaller
Solution Approach 1:
The patent employs a dynamic system with a compressible resilient member that adapts the gap distance between electrodes based on vessel size. The spring allows the electrodes to maintain an optimal gap for small vessels while preventing surface contact through its cushioning effect, providing dynamic adjustment rather than fixed positioning
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 forceps achieve consistent and effective tissue sealing by maintaining closure pressure within the optimal range, reducing the risk of mechanical failure and improving the reliability of vessel sealing, even for larger vessels, and enable precise cutting along the sealed tissue without the need for additional instruments.
Implementation Method 1
a four-bar mechanical linkage and a blade guide that includes a knife channel and stop members to control the distance between electrodes, facilitating consistent closure pressure
Implementation Method 2
electrical energy can be selectively transferred through the tissue. The electrode of each jaw member is charged to a different electric potential such that when the jaw members grasp tissue, electrical energy can be selectively transferred through the tissue
Implementation Method 3
to reduce the tissue impedance to a low enough value that allows enough electrosurgical energy through the tissue
Implementation Method 4
Vessel sealing is defined as the process of liquefying the collagen in the tissue so that it reforms into a fused mass
Data Source
AI summary
A bipolar endoscopic forceps including an elongated shaft having opposing jaw members at a distal end thereof and a blade guide operatively disposed between the jaw members. The jaw members are movable relative to one another about a pivot from a first position wherein the jaw members are disposed in a spaced relation relative to one another to a second position wherein the jaw members cooperate to grasp tissue therebetween. Each jaw member includes an electrically conductive sealing surface. The blade guide is configured to facilitate translation of a knife through a knife channel defined in the jaw members. The blade guide has an aperture defined therethrough for housing the pivot.