Electrosurgical Forceps Knife Lockout Mechanism
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Solution Overview
Problem
Existing electrosurgical forceps require surgeons to manually sever treated tissue after coagulation or cauterization, which can be challenging due to the need for precise cutting.
Innovation Solution
The electrosurgical forceps incorporate a knife deployment mechanism with a knife lockout system, allowing the knife to be selectively translated between retracted and extended positions, and only deployed when the jaw members are sufficiently approximated, ensuring precise tissue severing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a knife is integrated into electrosurgical forceps for tissue severing, then cutting precision and surgical efficiency are improved, but device complexity increases due to additional deployment mechanisms and lockout systems
Solution Approach 1:
The knife is integrated into the electrosurgical forceps by combining the cutting function with the existing grasping and electrosurgical treatment functions. The knife, deployment mechanism, and lockout system are incorporated within the forceps structure, allowing all functions (grasping, coagulation, cutting) to be performed by a single integrated device rather than separate instruments.
Solution Approach 2:
The lockout mechanism is designed to prevent knife deployment until the jaw members are properly closed around the tissue. This preliminary action ensures that the tissue is securely grasped before cutting occurs, preventing accidental deployment and ensuring proper surgical sequence. The lockout system activates the knife only after the jaw members are in the correct position.
2Reliability
If a lockout mechanism is added to control knife deployment, then operational safety and precision are improved, but ease of operation deteriorates due to additional control steps
Solution Approach 1:
The lockout mechanism provides mechanical feedback that prevents knife deployment until the jaw members are properly closed. The system senses the jaw closure state through the mechanical linkage and only permits knife translation when the correct conditions are met. This feedback ensures proper surgical sequence without requiring complex electronic controls or multiple manual steps.
Solution Approach 2:
The lockout mechanism is designed to automatically engage and disengage based on the jaw member position. When the jaws close around the tissue, the lockout automatically releases to permit knife deployment. When the jaws open, the lockout automatically re-engages to prevent accidental deployment. This self-service design reduces the cognitive load on the surgeon while maintaining safety.
3Manufacturing precision
If the knife is selectively deployable only when jaw members are approximated, then cutting precision is improved, but device complexity increases due to interdependent mechanisms
Solution Approach 1:
The knife is nested within the structure of the forceps, translating through the jaw members when deployed. The deployment mechanism is nested within the shaft members, and the lockout system is integrated into the existing pivot and linkage structures. This nesting allows the additional cutting function to be added without proportionally increasing the overall device size or complexity.
Solution Approach 2:
The knife transitions from a static retracted position to a dynamic extended position that protrudes between the jaw members. The deployment mechanism converts the rotational motion of the trigger into linear translation of the knife. The lockout mechanism dynamically engages and disengages based on jaw position, allowing the system to adapt its degree of freedom based on operational needs.
Data Source
AI summary
An electrosurgical forceps includes first and second shaft members pivotably coupled to one another via a pivot member such that pivoting of the first and second shaft members between spaced-apart and approximated positions pivots jaw members thereof between open and closed positions. A knife is translatable between retracted and extended positions. A knife deployment mechanism is operably coupled to the first shaft member and includes at least one trigger and at least one linkage coupling the at least one trigger with the knife such that pivoting of the at least one trigger relative to the first shaft member translates the knife between the retracted and extended positions. A knife lockout biased towards a locked position inhibits distal translation of the knife. The knife lockout is movable from the locked position to an unlocked position upon approximation of the jaw members to permit distal translation of the knife.