Electrosurgical Instrument Jaw Camming Mechanism
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Solution Overview
Problem
Existing electrosurgical forceps face challenges in effectively sealing and cutting large tissue structures due to inadequate control over mechanical parameters such as pressure and gap distance between electrodes, leading to potential short circuits and incomplete seals.
Innovation Solution
The design incorporates a surgical instrument with a housing and elongated shaft featuring pivotally coupled jaw members with camming slots and a drive rod, allowing precise control over jaw movement and pressure application, along with a knife mechanism for cutting, to ensure effective tissue sealing and cutting of large tissue structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrosurgical forceps are used to seal large tissue structures, then the ability to seal tissue is improved, but inadequate control over pressure and gap distance causes short circuits and incomplete seals
Solution Approach 1:
The patent applies parameter changes by incorporating a spring mechanism that automatically controls the closure pressure within the optimal range of 3-16 kg/cm² for sealing large tissue structures. The spring's mechanical properties are specifically designed to maintain consistent pressure and gap distance between electrodes, eliminating the need for manual pressure control and ensuring reliable seals without short circuits.
Solution Approach 2:
The patent replaces manual mechanical control with an automated spring-based mechanical system. The spring mechanism automatically regulates the force applied to the tissue, substituting the surgeon's manual pressure control with a pre-calibrated mechanical system that maintains optimal pressure parameters throughout the sealing process.
2Reliability
If pressure is increased to seal large tissue structures, then sealing effectiveness is improved, but excessive pressure causes tissue damage and incomplete seals
Solution Approach 1:
The spring mechanism is designed with specific mechanical properties to maintain closure pressure within the optimal range of 3-16 kg/cm². This parameter control ensures sufficient pressure for complete sealing of large tissue structures while preventing excessive pressure that would cause tissue damage or incomplete seals.
3Reliability
If gap distance between electrodes is reduced to improve seal, then sealing effectiveness is improved, but electrode contact causes short circuit
Solution Approach 1:
The spring mechanism maintains a precise gap distance between the electrodes that is optimized for energy transfer efficiency. By controlling the compression distance of the spring, the system ensures the electrodes remain at the correct separation distance during sealing, preventing both short circuits and incomplete seals.
4Stability of the object's composition
If force applied to tissue is increased to prevent movement, then sealing stability is improved, but excessive force prevents adequate seal generation
Solution Approach 1:
The spring mechanism applies force within the optimal range to stabilize tissue during sealing without excessive compression. The spring's mechanical properties are designed to provide sufficient force to prevent tissue movement while maintaining the pressure within the 3-16 kg/cm² range necessary for adequate seal generation.
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
This design enables economical manufacturing of a surgical instrument capable of achieving consistent tissue seals and cuts in large tissue structures by precisely controlling pressure and gap distance, preventing short circuits and ensuring effective hemostasis.
Implementation Method 1
The electrodes are charged to opposite electrical potentials such that an electrosurgical current may be selectively transferred through tissue grasped between the electrodes
Implementation Method 2
A cam pin is supported by the drive rod such that longitudinal movement of the drive rod is imparted to the cam pin. The end effector includes an upper jaw member pivotally coupled to the distal portion of the elongated shaft about a pivot axis, and the upper jaw member includes a first pair of laterally spaced flanges each defining a camming slot for engaging the cam pin
Data Source
AI summary
A surgical instrument includes a housing that supports an elongated shaft. A selectively movable drive rod extends through the elongated shaft and carries a cam pin in a longitudinal direction. An end effector for surgically treating tissue is supported by the elongated shaft and includes upper and lower jaw members pivotally coupled to one another about a pivot axis. The upper jaw member includes a first pair of laterally spaced flanges, and the lower jaw member includes a second pair of laterally spaced flanges defining a camming slot for engaging the cam pin. The flanges are arranged in an offset configuration where one flange of the upper jaw member is positioned on a laterally exterior side of a corresponding flange of the lower jaw member, and the other flange of the upper jaw member is positioned on a laterally interior side of the other flange of the lower jaw member.