Endoscopic Clip Applier Segmented Coil Force Transmission
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Solution Overview
Problem
Current flexible endoscopic clip appliers are limited in their ability to apply significant force due to buckling, kinking, and friction issues, making it difficult to effectively clamp and suture tissues through an endoscope, especially in tortuous paths.
Innovation Solution
A flexible endoscopic clip applier with a long coil, manual actuator, and jaws that include a force limiter, energy storage device, and a mechanism for precise clip dispensing, allowing for controlled force application and rotation of jaws to improve mechanical advantage and prevent accidental clip dispensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible control element is used to allow the device to bend with the endoscope, then the device can navigate tortuous paths, but the pushing element buckles and cannot transmit sufficient force to the distal end
Solution Approach 1:
The flexible coil is segmented into multiple loops that can rotate relative to each other about the longitudinal axis. This segmentation allows the coil to navigate tortuous paths while maintaining force transmission capability, as each segment can independently adjust to path variations without compromising the structural integrity needed for force transmission.
Solution Approach 2:
The coil structure is designed to be dynamically adjustable, allowing rotation of segments relative to each other. This dynamic capability enables the device to adapt to tortuous paths while maintaining sufficient pushing force transmission to the distal end, resolving the contradiction between flexibility and force transmission.
2Strength
If a larger diameter flexible pushing element is used to resist buckling, then the pushing element can maintain structural integrity, but it imparts too much stiffness to permit flexing with the endoscopic instrument
Solution Approach 1:
The coil is divided into multiple rotatable segments that can flex relative to each other. This segmentation provides the necessary flexibility to conform to the endoscope's path while each segment maintains sufficient structural integrity to resist buckling under pushing loads.
Solution Approach 2:
The coil structure functions as a flexible element that can bend and rotate while maintaining structural integrity. The segmented coil design allows it to flex with the endoscope without requiring a larger diameter that would compromise adaptability.
3Adaptability or versatility
If a smaller diameter flexible pushing element is used to maintain flexibility, then the device can bend easily, but it is subject to kinking which results in little to no force being transmitted to the distal end
Solution Approach 1:
The segmented coil structure prevents kinking by allowing each segment to rotate independently, distributing bending stresses across multiple segments. This maintains flexibility for easy bending while preventing the kinking that would eliminate force transmission.
Solution Approach 2:
The dynamic rotation capability of each coil segment prevents kinking by allowing the structure to adapt to bending forces through controlled rotation rather than rigid deformation. This maintains both flexibility and force transmission capability.
4Adaptability or versatility
If the outer sheath is made stretchable to accommodate tortuous paths, then the device can navigate curved paths, but the force and relative movement of the pushing element are reduced or eliminated
Solution Approach 1:
The segmented coil structure accommodates tortuous paths through rotation of segments rather than stretching of the outer sheath. This maintains the structural integrity needed for force transmission while providing the adaptability to navigate curved paths.
Solution Approach 2:
The dynamic rotation of coil segments provides the necessary adaptability to tortuous paths without relying on elastic stretching. This preserves the pushing force transmission capability while enabling navigation of curved paths.
5Force
If a rigid jaw assembly is used to achieve high clamping force on tissue, then sufficient compression force can be applied, but the device cannot flex to accommodate the endoscopic path
Solution Approach 1:
The jaw assembly is integrated with the segmented coil structure, allowing the jaws to maintain rigidity for high clamping force while the segmented coil provides the flexibility to accommodate the endoscopic path. Each coil segment can rotate to navigate curves while the jaw assembly remains structurally sound.
Solution Approach 2:
The segmented coil acts as a flexible structural element that connects the proximal handle to the distal jaw assembly. This allows the jaw assembly to maintain rigidity for effective tissue clamping while the flexible coil accommodates the tortuous path of the endoscope.
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
Enables precise and controlled application of clips with consistent resistance, preventing excessive force and ensuring accurate tissue fixation while accommodating changes in the endoscope's path length, thereby enhancing the capability for minimally invasive surgical procedures.
Implementation Method 1
a compression spring coupled to the control member proximal of the jaw assembly and movable relative to the coil. The spring is adapted to store energy when compressed by excessive force applied to the control member
Implementation Method 2
a torsion spring coupled to the manual actuator and to the control member. The torsion spring is adapted to store energy when rotated by the manual actuator
Implementation Method 3
a friction element coupled to the control member and adapted to resist motion of the control member relative to the coil
Data Source
AI summary
A flexible endoscopic clip applier includes a flexible coil with a manual actuator coupled to one end and a jaw assembly coupled to the other end. A store of clips is arranged adjacent to the jaw assembly and a clip pusher is arranged adjacent to the store of clips. The actuator includes a lever for opening and closing the jaws, a knob for rotating the jaw assembly, and a crank for dispensing clips. The knob and the lever are coupled to a single control member which extends through the coil to a joiner where it is joined to a pair of pull wires coupled to the jaws. The crank is coupled to a second control member which is threaded along a distal portion. The threaded portion engages a threaded member near the pusher and is coupled to the pusher such that rotation of the threaded control member by the crank causes the pusher to be moved distally.