Cam-Driven Suturing Needle Motion for Precise Tissue Placement
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Solution Overview
Problem
Existing surgical suturing methods using graspers or needle drivers often result in inaccurate suture placement, tissue damage, and increased risk of needle sticks due to inadequate grip, pressure control, and needle deformation, leading to compromised wound healing and surgeon discomfort.
Innovation Solution
A suturing device with a housing and actuation lever that allows for precise placement of two needles with consistent pressure, eliminating the need for graspers or needle drivers, and featuring a follower plate and cam path mechanism for single-handed operation and needle retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If graspers are used to hold and control the needle, then the needle can be manipulated during suturing, but the grip is not secure enough, increasing the risk of needle slipping or rotating
Solution Approach 1:
The patent introduces a needle holder as an intermediary device between the grasper and the needle. The needle holder provides a secure grip on the needle through its jaws, preventing slipping and rotation, while still allowing the grasper to manipulate the overall assembly. This intermediary component resolves the contradiction by decoupling the manipulation function from the secure gripping function.
2Productivity
If needle drivers are used to drive the needle through tissue, then suturing can be performed, but inadequate pressure makes it difficult to properly grasp and drive the needle
Solution Approach 1:
The patent employs a dynamic pressure application mechanism where the needle holder's jaws can adaptively apply varying levels of pressure to the needle. The mechanism allows the surgeon to control the pressure magnitude, enabling proper needle grasping and driving without excessive force that could deform the needle or cause tissue damage. This dynamic control resolves the contradiction between productivity and force application.
3Force
If excessive pressure is applied to the needle with the driver, then the needle can be driven through tissue, but the needle deforms or bends, compromising its ability to pass smoothly through tissue
Solution Approach 1:
The needle holder serves as a protective intermediary between the driving mechanism and the needle. Its jaws are designed to apply force distributed along the needle shaft, preventing localized stress concentrations that would cause bending. The holder's structure allows force transmission while maintaining needle geometry, thus resolving the contradiction between driving force and shape preservation.
4Reliability
If the jaws of the driver are worn or damaged, then the needle may slip during suturing, but using a well-maintained driver ensures secure needle grip
Solution Approach 1:
The patent divides the needle holding function into separate components: the needle holder with replaceable jaws and the main driver body. This segmentation allows the jaws to be easily replaced when worn or damaged without affecting the rest of the device. The modular design maintains reliability while simplifying maintenance, as the jaws can be swapped out without replacing the entire driver assembly.
5Ease of operation
If an ill-fitting or poorly designed needle driver is used, then the device can be operated, but it causes discomfort and fatigue, affecting the surgeon's dexterity and focus
Solution Approach 1:
The patent applies local quality improvements to the needle holder's gripping surfaces, designing jaws with specific geometric features and material properties that provide secure needle engagement. The local optimization of the gripping interface improves operability while reducing the overall force required by the surgeon, thereby minimizing discomfort and fatigue during prolonged procedures.
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 consistent and precise suture placement with reduced risk of tissue damage and needle sticks, improving surgical efficiency and reducing surgeon fatigue.
Implementation Method 1
a slot defining a cam path is formed in a first portion of the actuation lever, the actuation lever configured to be displaceable from an unactuated first lever position to an intermediate second lever position to a fully actuated third lever position by displacing the actuation lever in a single direction. The embodiment of the suturing device may further include a follower plate that includes a cam follower that is disposed within the slot defining the cam path of the actuation lever
Data Source
AI summary
A suturing device includes an actuation lever having a displaceable actuation lever having a cam path is formed in a portion of the actuation lever. A cam follower of a follower plate is disposed in the cam path such that as the actuation lever is displaced from a first position to an intermediate position, the follower plate is displaced from a proximal position to a distal position thereby displacing a first needle coupled to the follower plate from a first position to a second position, and as the actuation lever is displaced from the intermediate position to a third position, the follower plate is displaced from the distal position to the proximal position, thereby displacing the first needle from the second position to the first position.