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Figure 4 Knot: Simple Tying Technique for Robotic and Endoscopic Sutures

Ishikawa, Norihiko MD, PhD; Watanabe, Go MD, PhD

Innovations: Technology & Techniques in Cardiothoracic & Vascular Surgery: March/April 2017 - Volume 12 - Issue 2 - p 152–153
doi: 10.1097/IMI.0000000000000348
How-To-Do-It Articles

Abstract: Various endoscopic suturing and tying methods have been reported, but these methods remain imperfect because knots are sometimes not tied completely and additional stitches are needed. To address this problem, we developed the “Figure 4” technique in which the knot can be easily slid to the suture point and tied by pulling suture tail—these knots will never come untied. This technique requires very simple technique and can be used in other surgical procedures such as conventional laparoscopic surgery.

From the Department of Cardiovascular Surgery, NewHeart Watanabe Institute, Tokyo, Japan.

Accepted for publication December 7, 2016.

A video clip is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site (www.innovjournal.com).

Disclosure: The authors declare no conflicts of interest.

Address correspondence and reprint requests to Norihiko Ishikawa, MD, PhD, NewHeart Watanabe Institute, 3-19-11 Hamadayama, Suginami-ku, Tokyo 168-0065, Japan. E-mail: iskwnrhk@gmail.com.

Recently, minimally invasive cardiac surgeries such as robotic surgery and minimally invasive cardiac surgery have enabled surgeons to perform robotic- or video-assisted atrial septal defect (ASD) closures, mitral valve repairs, and other procedures.1 However, it remains technically demanding to completely close atrial and cardioplegia openings to prevent postoperative bleeding. In this article, we present a simple and effective knot tying technique called “Figure 4” in which the knot can be easily slid to the suture point and tied by pulling suture tail—these knots will never come untied.

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Technique

We use a transthoracic approach for robotic or minimally invasive cardiac surgery procedures for ASD closure and mitral valve repair.2 After fixing the ASD of MV, the atrial opening is closed with 4-0 Gore-Tex suture (CV-4; W.L. Gore & Associates, Flagstaff, AZ USA) using a running suture technique. In this article, we describe our technique for atrium closure after robot-assisted ASD closure.

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Creating a Small Loop

Before starting atrial suture, create a small loop at the distal end of the suture approximately 3 cm from the end of the suture thread (Fig. 1A). For the edge of the running suture, the needle is first passed through the distal loop and the loop is tightened (Fig. 1B). The running suture is then continued (Fig. 1C).

After reciprocating the running suture, the Figure 4 technique is used at the final edge of the suture (Video 1, http://links.lww.com/INNOV/A116). The following steps describe our technique for the Figure 4 in detail.

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Formation of a “4” by Overwrapping

The tail of CV-4 is pulled around to form a loop in the shape of a “4” with an overwrap (Fig. 2A). At this stage, the right instrument continues to hold the free end of the suture, while the patient-side assistant holds the external end of the suture loosely.

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Formation of the Knot

The left instrument holding the end of the suture is passed though the “4” to form the knot (Figs. 2B, C). At this stage, the patient-side assistant starts to apply gentle traction on the external end of the suture.

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Completion of the Knot

The external suture is grasped with the right instrument. Traction is applied with both instruments. This is easily remembered as a conversion of the “4” to a “Q” (Fig. 2D).

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Formation of the Second “Mirror Image of 4”

At this stage, the instruments release the tip and regrasp the suture a few centimeters from the tip. The left instrument is withdrawn and rotated slightly to allow the short end of the suture to be wrapped around the formation to form a “mirror image of 4,” and completion of the suture in opposite directions is possible (Fig. 2E). Additional knots maybe fashioned to complete the square knots.

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DISCUSSION

Complete closure of incision or hole is a very important step in preventing bleeding during cardiac surgery. Various endoscopic suturing and tying methods have been reported.3,4 Knot pushers and simple intracorporeal tying methods using robotic instruments have been used in robot-assisted cardiac surgery.5 However, these methods remain imperfect because knots are sometimes not tied completely and additional stitches are needed. To address this problem, we developed the Figure 4 technique as a helpful tool. This technique is significantly easier to perform, and the knot is not loosened by traction. Furthermore, this Figure 4 technique is useful for not only robotic surgery but also conventional endoscopic surgery.

The Figure 4 technique has two merits: it is very easy and not too loose. This technique makes knot tying dramatically easier because the console surgeon can use two instruments at the same time, which allows the pulling of one suture to prevent loosening of the knot in the deep operative field. Because the patient-side assistant pulls one end of the suture during knot tying, the knot does not loosen after it is tightened. After ligation with two instruments, a second simple square knot can be made easily and tied tightly; therefore, this method requires that knots be tied several times.

In this article, we described a technique for atrial closure followed by intracardiac maneuver. However, it is also applicable not only in atrial repair but also for the suturing of cardioplegia holes as well as in a number of situations during robotic cardiac surgery. To perform a conventional laparoscopic suture and to tie a knot, the surgeon must practice on a simulator before clinical application. Our new method, the Figure 4 technique requires a very simple technique and can be used in other surgical procedures such as conventional laparoscopic surgery.

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REFERENCES

1. Nifong LW, Chitwood WR, Pappas PS, et al. Robotic mitral valve surgery: a United States multicenter trial. J Thorac Cardiovasc Surg. 2005;129: 1395–1404.
2. Ishikawa N, Watanabe G. Ultra-minimally invasive cardiac surgery: robotic surgery and awake CABG. Surg Today. 2015;45:1–7.
3. Ko S, Airan MC. Therapeutic laparoscopic suturing techniques. Surg Endosc. 1992;6:41–46.
4. Pennings JL, Kenyon T, Swanstrom L. The knit stitch. An improved method of laparoscopic knot tying. Surg Endosc. 1995;9:537–540.
5. Watanabe G, Ishikawa N. Alternative method for cardioplegia delivery during totally endoscopic robotic intracardiac surgery. Ann Thorac Surg. 2014;98: 1129–1131.
Keywords:

Robotically-assisted cardiac surgery; Endoscopic surgery; Suture tying

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©2017 by the International Society for Minimally Invasive Cardiothoracic Surgery