Actuation Mechanisms for Tissue Specimen Retrieval Devices
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Solution Overview
Problem
Minimally-invasive surgical procedures face challenges in retrieving large tissue specimens due to restricted access and the need to prevent cancer cell seeding, often requiring specimens to be broken down, which complicates retrieval within an enclosed environment.
Innovation Solution
A tissue specimen retrieval device with a housing and outer shaft featuring actuatable jaws that expand to deploy a tissue specimen bag, allowing for the collection and closure of specimens without additional deployment arms, utilizing a pin-driven actuation mechanism and sutures for bag control, facilitating intact specimen retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a large tissue specimen is retrieved through minimally-invasive openings, then the specimen can be removed from the body, but the restricted access prevents intact retrieval and requires breaking down the specimen into smaller pieces
Solution Approach 1:
The tissue specimen bag is nested within the outer shaft in a collapsed state during insertion, then deployed to an expanded state for specimen retrieval. This allows the retrieval device to transition from a compact insertable form to an expanded operational form, enabling intact specimen removal through restricted access openings without requiring the specimen to be broken down into smaller pieces
2Ease of operation
If additional deployment arms are added to expand the bag, then the bag can be deployed for specimen collection, but the device complexity increases
Solution Approach 1:
The first and second jaws are combined into a single integrated actuation mechanism that simultaneously controls the expansion of the bag brim. The shared actuator moves both jaws together through coordinated pivotal motion, eliminating the need for separate deployment arms for each jaw while maintaining controlled bag deployment capability
3Ease of operation
If the jaws are actuated to expand the bag brim, then the bag can open for specimen collection, but the maneuverability through minimally-invasive openings is reduced
Solution Approach 1:
The device transitions dynamically between two states: a compact closed configuration during insertion and navigation through minimally-invasive openings, and an expanded open configuration for specimen collection. The jaws and bag brim are designed to pivot and expand only when needed, maintaining a small profile during transit while providing full functionality during the retrieval operation
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 the retrieval of tissue specimens in an intact form within an enclosed environment, reducing the risk of cancer cell seeding and improving maneuverability through minimally-invasive openings by expanding the bag for specimen collection and cinching it closed for removal.
Implementation Method 1
Advancing the pin along a proximal to distal direction actuates the first and second jaws between the closed configuration and the expanded configuration
Implementation Method 2
Actuation of the first jaw and the second jaw between the closed configuration and the expanded configuration pivots the first jaw about the first and second pivot points and pivots the second jaw about the third and fourth pivot points to expand the bag brim
Implementation Method 3
The second suture is configured to cinch the bag brim into a closed configuration
Data Source
AI summary
A tissue specimen retrieval device includes an outer shaft including a proximal portion and a distal portion. The distal portion of the outer shaft includes a first jaw defining a first side of a lumen in the distal portion of the outer shaft. A second jaw defines a second side of the lumen in the distal portion of the outer shaft. The first and second jaws are actuatable between a closed configuration and an expanded configuration in which the first and second jaws are spaced relative to each other. A tissue specimen bag is supported by the first jaw and the second jaw. A bag brim of the tissue specimen bag defines a collapsed configuration when positioned in the lumen defined by the first jaw and the second jaw and an open configuration when the first and second jaws are in the expanded configuration.