Surgical Stapler Rotatable Cam for Sequential Staple Ejection
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Solution Overview
Problem
Existing surgical stapling devices with rigid shafts face challenges in accessing hard-to-reach surgical sites, such as the ascending or transverse colon, leading to increased patient trauma and recovery time during open colectomy procedures.
Innovation Solution
A surgical stapling device with a flexible outer tube and a tool assembly featuring a segmented pusher assembly and a pusher drive mechanism that includes a cam member, allowing for independent movement of pushers to eject staples, and a gear system for approximating the anvil assembly, minimizing firing forces and facilitating access to difficult-to-reach surgical sites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid shaft is used in the surgical stapling device, then structural strength and stability are improved, but accessibility to hard-to-reach surgical sites deteriorates
Solution Approach 1:
The pusher assembly is divided into multiple independently movable pushers (first pusher, second pusher, etc.) arranged circumferentially. Each pusher can be advanced independently by the cam member to eject staples from different positions in the staple cartridge, enabling the device to adapt to various surgical configurations and access difficult-to-reach areas while maintaining structural integrity
Solution Approach 2:
The pushers are designed to be movable rather than fixed, allowing them to be advanced independently as needed. The cam member enables dynamic control of each pusher's position, allowing the device to adapt its configuration during operation to reach different surgical sites while maintaining overall structural strength through the rigid housing and controlled movement mechanism
2Productivity
If multiple pushers are advanced simultaneously to eject all staples, then productivity is improved, but firing forces required exceed available forces
Solution Approach 1:
The cam member is designed to sequentially advance the pushers in a step-by-step manner rather than simultaneously. As the cam member rotates, it engages each pusher's cam surface in sequence, causing the pushers to advance periodically one after another. This periodic action allows multiple staples to be ejected over time without requiring all pushers to be advanced at once, keeping firing forces within available limits while maintaining productivity
Solution Approach 2:
The cam member is positioned and oriented such that it can engage and advance multiple pushers in a predetermined sequence. The cam surfaces on each pusher are positioned to be engaged by the cam member at different rotational positions, allowing the system to pre-plan the ejection sequence and manage forces accordingly before the actual ejection process begins
3Ease of operation
If a rotary pusher mechanism is used to eject staples, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The cam member serves multiple functions: it acts as the driving element that advances all pushers, provides the sequential timing mechanism through its rotation, and acts as the control element that determines the ejection sequence. This multi-functionality reduces the need for separate control mechanisms for each pusher, simplifying the overall device complexity while maintaining ease of operation through a single rotational input
Solution Approach 2:
The cam surfaces on each pusher are designed to be automatically engaged by the cam member in sequence during rotation. The geometry of the cam surfaces and the rotational motion of the cam member create a self-regulating mechanism where each pusher advances only when the cam member reaches its specific engagement position, eliminating the need for additional sensors, actuators, or control systems for each individual pusher
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 flexible shaft design enables easier access to hard-to-reach surgical sites, reducing patient trauma and recovery time by allowing for minimally invasive procedures.
Implementation Method 1
The pusher drive is rotatable to move the cam member into sequential engagement with the cam surfaces of the plurality of pushers of the segmented pusher to sequentially advance the plurality of pushers
Implementation Method 2
the threads on the outer surface of the threaded spline tube are engaged with the inner threaded surface of the pusher drive such that rotation of the pusher drive about the threaded spline tube causes longitudinal movement of the pusher drive
Data Source
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AI summary
A surgical stapling device that includes an adapter assembly that has a flexible outer tube, and a tool assembly that is supported on the flexible outer tube having an anvil assembly and a shell assembly that supports an annular staple cartridge. The shell assembly includes a mechanism for approximating the anvil assembly with the shell assembly over two clamping stages to minimize forces transferred to the flexible outer tube of the adapter assembly during clamping. The shell assembly also includes a mechanism for minimizing firing forces required to eject staples from the staple cartridge.