Knot Placement Device for Suture Cutting and Ejection
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Solution Overview
Problem
Surgeons face challenges in efficiently tying and cinching sutures, especially in regions with restricted access, such as the heart, due to the difficulty in handling sutures, which increases procedural time.
Innovation Solution
A knot placement device with a knot body and plug design that secures the suture between the knot body and plug, allowing for easy ejection, cutting, and release of the suture, reducing the force required to cut stretchable sutures using a rotatable cutting surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a surgeon manually ties and cinches a suture in a region with restricted access, then the suture can be secured to join tissue portions, but the procedure becomes time-consuming and difficult to handle
Solution Approach 1:
The suture system is divided into separate components: a suture portion with pre-formed knot and a separate plug. The knot is pre-formed outside the body and loaded onto the suture, then deployed internally. This segmentation allows the complex knot-tying function to be performed externally where it is easier to manipulate, while the deployment inside the restricted access region is simplified to a single insertion and activation step.
Solution Approach 2:
The knot is pre-formed on the suture portion before insertion into the patient's body. The suture is prepared with the knot already tied and cinched in the optimal configuration externally, then the entire assembly is inserted through a catheter or delivery system. This preliminary action eliminates the need to perform complex knot-tying maneuvers inside the restricted access region.
2Ease of operation
If a rotating cutting surface is used to cut the suture, then the suture can be severed from the device, but stretchable sutures require excessive force that may damage the device or tissue
Solution Approach 1:
A cutting element is introduced as an intermediary between the rotating component and the suture material. Instead of relying solely on friction from rotation against the suture, a dedicated cutting edge or blade is used to mechanically sever the suture. This intermediary cutting element requires minimal force to cut through the suture material, even when the suture is stretchable, and prevents excessive force transmission to the device or surrounding tissue.
3Strength
If the knot is secured tightly between the knot body and plug, then the suture is firmly held, but ejecting the knot becomes difficult
Solution Approach 1:
The retention mechanism transitions from a static tight fit to a dynamic system with controlled release. The plug is initially positioned to firmly hold the knot body against the suture, providing strong retention. However, the system includes a release mechanism that allows the plug to be withdrawn or repositioned, dynamically changing the retention force from high to low, enabling easy ejection of the knot when needed.
Solution Approach 2:
The knot is pre-formed and secured in its final configuration before insertion. Once deployed and secured between the knot body and plug, no further manipulation is needed. The preliminary formation and securing of the knot eliminates the need for complex manipulation during ejection, as the knot is already in its functional state and can be simply withdrawn as a complete unit.
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
Knot placement devices and methods can improve the ease for a user and/or success of ejecting a knot having a knot body and a plug, cutting suture and/or releasing the cut suture. The knot placement device can have an incremental rotational feature to cut the suture. The knot placement device can include first and second actuators configured for forming and ejecting a knot. The second actuator can be reversed in its position to release suture(s) caught within the device.