Mastering efficient Cor-Knot skills: novel S technique for solo automated suture fastening

Introduction

The Cor-Knot (CK; LSI Solutions, Victor, NY, USA) automated suture securement device featuring titanium fasteners is extensively used in cardiac procedures, especially in valve surgeries. It provides a quick and secure alternative to hand-tied knots, effectively reducing suture tying times. Multiple studies have highlighted its distinct benefits, namely reduced operative, aortic cross-clamp (ACC), and cardiopulmonary bypass (CPB) times and less risk of paravalvular regurgitation leaks (1,2). Beyond valvular applications, the CK is also effective for decannulation site hemostasis (3,4) and left atrial appendage closure (5), broadening its suitability for cardiac surgeries.

The system’s key components include its shaft, curved handle, wire snare, and crimpable titanium fasteners. A scrub nurse preliminarily loads the device with CK fasteners by inserting and rotating the curved handle into the shaft’s distal slot and removing the purple target marker. However, existing resources do not specify optimal handling techniques by surgeons, and instructions for efficient solo use are lacking.

Herein, we introduce the so-called S technique for efficient, solo CK operation, a method that minimizes unnecessary movements and maximizes surgical efficiency. Surgeons may thereby harness the full device potential during cardiac surgery. We present this article in accordance with the SUPER reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2024-1985/rc).

Preoperative preparations and requirements

In cardiac surgeries, particularly those directed at valve annulus, the CK device facilitates reliable suture placement (without loosening) so that ACC and CPB times are reduced. Preoperatively, the scrub nurse prepares the device at tableside according to the standard loading protocol for a CK quick-load unit. This process involves inserting the blunt tip of the curved handle into the distal slot of the CK device shaft. The handle is then rotated until the fastener is positioned securely within the distal slot, at which point the purple target marker is pushed out and removed. The device is then ready for efficient intraoperative use.

Step-by-step description

To apply our technique, the right hand holds the device (white handle), using the left hand for suture control (Video 1). The left hand is functionally divided into part A (thumb plus index finger) and part B (three remaining fingers) (Figure 1). At the start, part B (middle finger included) is tasked with holding the suture taut. The loaded device (within right hand) is then moved close to left middle finger, placing the wire snare (at shaft’s distal end) over the suture (Figure 2A). Using part A (thumb/index finger) of left hand, both ends of suture are subsequently passed through the wire snare.

Figure 1 Surgeon’s left hand illustrating part A (thumb plus index finger) and part B (three remaining fingers) divisions of S technique for optimal control.

Figure 2 Step-by-step S technique depiction using CK practice kit. (A) Wire snare (at shaft’s end) positioned over suture, holding suture taut (part B) for part A (thumb + index finger) delivery of both suture ends through snare (white arrow). (B) Once suture captured, tightly held (no release), and sufficient slack created (part B), grasping/pulling of curved metal handle (part A) draws suture into CK fastener for secure placement (white asterisk, curved handle; black asterisk, CK fastener). (C) Suture threaded through CK fastener by pull on curved handle, using key fingers (black arrow, part B) to retain suture and wire snare (white arrow) in one grasp once both suture ends leave shaft exit hole. (D) Using part B, maintain a firm hold on the suture material, wire snare, and curved handle together. While keeping control with part B, use part A (white asterisk) to adjust the indicator fin. White arrow, throughout the entire ‘S technique’, the assistant ensures additional time savings by exposing the valve annulus. CK, Cor-Knot.

Once ensnared, the suture is held securely (without release) using part B-induced tension to create sufficient slack. To draw the suture into the CK fastener (Figure 2B), the curved metal handle is grasped using part A and pulled, bringing the attached wire snare (with suture) toward the purple lever. This is where the ensnared suture ends are delivered into the fastener. Pull is exerted until the suture exits through a slot near the shaft’s end. Meanwhile, suture control is maintained by part B, ensuring continuous hold on the wire snare and curved handle for enhanced efficiency (Figure 2C).

With part B hold sustained (as above), the indicator fin is also adjusted (rotated, part A), orienting the suture exit hole toward prosthetic valve center (Figure 2D). Finally, a standard exit sequence is executed as elaborated below.

Postoperative considerations and tasks

Ensuring that the device is properly positioned and secured on the outer ring of the valve, the purple lever is fully engaged for one second while holding the device tip in place (6). A gentle tug on the suture frees both ends, the lever is released, and the device is removed, leaving a crimped CK fastener intact.

Tips and pearls

When threading suture through the wire snare, a surgeon’s own thumb and index finger must be used, rather than relying on assistant input or forceps. Avoid setting the suture down or repositioning it, thus injecting unnecessary action and causing delay (Video 1). Many surgeons also mistakenly release an already ensnared suture to reach for the curved handle. Such missteps interrupt flow and prolong procedures.

Once suture is threaded through the CK fastener, and both wire snare and curved handle are extracted, there is no need to readily dispose of the curved handle or set it on the scrub table mid-procedure. Instead, it is best to proceed with rotating/aligning the indicator fin and completing the suture cut, thereafter returning the entire device (including suture material and curved handle) to the scrub table. This approach eliminates wasted steps and saves time.

Throughout these maneuvers, subtle right-hand adjustments are reasonably made relative to left-hand movements. This guide clearly presumes certain handedness, which surgeons may switch at their discretion. However, by precluding involvement of others in CK deployment, the surgical focus does not stray, ultimately rendering the process more expeditious. Handling of various tasks (threading, holding, etc.) by an assistant does not necessarily improve procedural speed or efficiency.

Discussion

The CK automated suture fastening device is widely recognized for its advantages in cardiovascular surgeries, offering a superior, secure, and efficient alternative to hand-tied knots. Studies have documented its capacity for reduced operative times, including ACC and CPB durations, and fewer resultant complications, such as paravalvular leaks (1,2). Still, techniques that maximize device efficiency seemingly remain unexplored. Our novel S technique helps to further reduce time requirements though solo CK handling, eliminating steps reliant on staff assistance.

Once exempted from CK-related efforts, such as suture ensnarement or curved handle removal, there are other essential tasks (i.e., valve exposure or stabilization of the prosthetic valve’s instrument handle) for assistants to address, potentially affording greater time savings. Our experience shows that unlike traditional methods, the intermediate steps eliminated via S technique serve to shorten a procedure by more than 3 seconds per CK load unit. Assuming that 12 or more CK units are needed for complete prosthetic valve implantation, this has the potential to meaningfully reduce total ACC time. However, above all, the most significant advantage of the S technique is its utility for surgeons to effectively perform procedures independently in situations where assistance is not readily available.

In naming our approach, we have tentatively adopted the term S technique, reflecting its emphasis on solo performance and speed. Even as surgical technologies advance, surgeons should aim to refine their manual skills, boosting core competencies that ensure streamlined and precision operations. Future research may focus on quantifying the benefits, such as clamping time reduction, while also investigating how assistants could further enhance the procedure in various surgical configurations.

Conclusions

The CK device offers substantial time savings in cardiac surgeries, with further efficiency achievable through our S technique. This streamlined approach allows surgeons to manage the device swiftly, precisely, and independently, avoiding unnecessary movements and harnessing full device functionality.

Acknowledgments

We gratefully acknowledge the access granted to a Cor-Knot practice kit, enabling us to develop and refine the technique presented herein.

Footnote

Reporting Checklist: The authors have completed the SUPER reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2024-1985/rc

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2024-1985/prf

Funding: None.

Conflicts of Interest:All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2024-1985/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of this work in ensuring that questions related to accuracy or integrity of any part are appropriately investigated and resolved. All procedures as described were undertaken in accordance with institutional ethical standards of the Ethics Committee of Uijeongbu Eulji Medical Center (No. NON2025-001).

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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