V-Shaped Retrieval Device Arms for Distal Object Capture
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Solution Overview
Problem
Current retrieval devices for removing obstructions from within a patient's body cavities or passages often face challenges in effectively grasping and removing objects, particularly due to their design limitations that can lead to difficulty in capturing objects near the distal end or requiring longitudinal movement, which may cause complications during procedures like lithotripsy.
Innovation Solution
The retrieval device features a unique end effector with a 'butterfly' configuration, comprising a sheath, first, second, and third arms, and preformed bends in the members that allow the arms to transition between contracted and expanded states, forming a V-shape with an open mouth, enabling effective grasping and positioning of objects without longitudinal movement, and facilitating the capture of objects near the distal end or on the sides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional retrieval devices are used, then they can remove obstructions from body cavities, but they have difficulty grasping objects near the distal end or on the sides
Solution Approach 1:
The retrieval device is divided into multiple arms (first arm, second arm, third arm) that can be independently positioned and controlled. Each arm can be selectively extended or repositioned to reach objects at different locations, including the distal end or side positions, allowing the device to grasp objects that would be inaccessible to a single-construction retrieval device
Solution Approach 2:
The device transitions from a linear configuration to a three-dimensional V-shape configuration when expanded. The first and second arms form angled legs of the V-shape while the third arm extends along the longitudinal axis, creating spatial coverage in multiple dimensions that enables grasping objects at the distal end or on the sides of body cavities
2Ease of operation
If conventional retrieval devices require longitudinal movement to capture objects, then they can reach objects, but this causes complications during procedures
Solution Approach 1:
The retrieval device dynamically transitions between a contracted state (for insertion and navigation) and an expanded V-shape state (for object capture). Once expanded, the arms can be repositioned independently to capture objects without requiring longitudinal movement of the entire device, thereby avoiding complications associated with moving the device back and forth during the procedure
Solution Approach 2:
The device is expanded to its V-shape configuration before attempting to capture the object. This preliminary expansion establishes the optimal grasping geometry in advance, allowing the operator to position and secure the object using the angled arms without needing to perform longitudinal movements that could cause complications
3Ease of manufacture
If the retrieval device uses a simple arm structure, then the device is easier to manufacture, but it cannot form effective grasping configurations
Solution Approach 1:
The device employs an asymmetric V-shape configuration where the first and second arms form angled legs and the third arm extends along the longitudinal axis. This asymmetric arrangement provides superior grasping capability compared to symmetric designs, as it allows differential positioning of each arm to accommodate objects at various locations and orientations within the body cavity
Data Source
AI summary
A retrieval device may have a contracted state and an expanded state and may include a sheath defining a longitudinal axis; a first arm, a second arm, and a third arm; a first member extending between a distal end of the first arm and a distal end of the third arm; and a second member extending between a distal end of the second arm and the distal end of the third arm. In the expanded state and from a distal-end view, the first and second members and the distal ends of the first arm, second arm, and third arm may form a V-shape with an open mouth.