Torque Limiting Mechanism for Controlled Tissue Compression
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Solution Overview
Problem
Current surgical stapling instruments lack a user-selectable mechanism to control tissue compression, leading to potential tissue damage from excessive compression or leaks and bleeding due to insufficient clamping.
Innovation Solution
A torque limiting mechanism is introduced, comprising a driven member and a driving member with interengaging surfaces that slip at a predetermined pressure, allowing for adjustable compression control through a spring-biased engagement system and torque control mechanism, ensuring controlled tissue compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the operator compresses the tissue sections until the instrument reaches a set approximation, then the tissue is clamped with sufficient compression to prevent bleeding and leaks, but excessive compression may lead to tissue damage or restricted blood flow causing tissue necrosis
Solution Approach 1:
The patent applies parameter changes by introducing a torque limiting mechanism that controls the compression force applied to tissue. The mechanism includes a spring with adjustable preload that limits the maximum torque transmitted to the clamping members, thereby controlling the compression parameter within a safe range. This resolves the contradiction by automatically adjusting the compression parameter to prevent both insufficient clamping and excessive compression damage.
Solution Approach 2:
The patent implements feedback through a torque limiting mechanism that continuously monitors and regulates the compression force. The spring-based torque limiter provides real-time feedback by mechanically limiting the torque transmission when a predetermined compression force is reached, preventing over-compression. This feedback mechanism ensures reliable anastomotic joint integrity while protecting against tissue damage.
2Object-affected harmful factors
If a torque limiting mechanism is introduced to prevent excessive compression, then tissue damage is reduced, but the device complexity increases due to additional components
Solution Approach 1:
The patent uses an intermediary element - a spring-based torque limiting mechanism - that mediates between the operator's input force and the tissue compression. This intermediary component passively limits torque transmission without requiring active control systems, electronic sensors, or complex feedback circuits. The spring acts as a mechanical intermediary that automatically regulates compression force, reducing tissue damage while adding minimal device complexity.
Solution Approach 2:
The torque limiting mechanism is designed to be self-regulating and self-adjusting without requiring external control systems. The spring-based limiter automatically adjusts to maintain compression force within safe limits throughout the stapling process. This self-service capability prevents tissue damage while avoiding the complexity of electronically controlled force regulation systems.
3Reliability
If the driving surface slips relative to the driven member at a predetermined engagement pressure, then controlled compression is achieved, but the precision of torque transmission is reduced
Solution Approach 1:
The patent applies beforehand cushioning by using a spring-based torque limiting mechanism that pre-limits the maximum torque transmission before excessive compression can occur. The spring is pre-loaded to a predetermined torque level, providing a cushioning effect that prevents torque overshoot and ensures controlled compression from the outset. This approach prioritizes reliable compression control over precise torque transmission, accepting some torque loss as a necessary trade-off for preventing tissue damage.
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 mechanism prevents over-compression of tissues by limiting the torque applied, thereby reducing the risk of tissue damage and ensuring consistent anastomotic joint integrity.
Implementation Method 1
The driving surface of the driving member slips relative to the driven surface of the driven member at a predetermined engagement pressure
Implementation Method 2
a spring-biased engagement system and torque control mechanism
Data Source
AI summary
There are provided torque limiting mechanisms (40,110,140) for use in tissue clamping surgical instruments (10). The torque limiting mechanisms (40,110,140) generally include a driven member (78,112,142), engageable with an approximating mechanism of the surgical instruments (10), and having a driven surface (80,130,156) and a driving member (82,114,144) having a driving surface (84,132,158) engageable with the driven surface (80,130,156) of the driven member (78,112,142). The driving member (82,114,144) is rotatable relative to the driven member (78,112,142) such that the driving surface (84,132,158) of the driving member (82,114,144) slips relative to or disengages from the driven surface (80,130,156) of the driven member (78,112,142) at a predetermined engagement pressure.