Continuous Suture

The goal of the exercise is to create a continuous suture by following five consecutive marked squares in an up-and-down pattern.

Any sequence of five squares can be selected. On newer versions of the flat lung, groups of five squares are conveniently marked with an arrow for easier identification.

Suture...

A 4/0 PDS stitch with a 20 mm 1/2 round needle is recommended.

Introduction

This exercise is designed to develop essential VATS suturing skills, focusing on:

• Inserting the needle on a needle driver into the chest cavity.
• Controlling the tip and rotation of the needle driver to pass the needle through tissue safely and efficiently.
• Handling the suture to prevent tangling.
• Mastering both backhand and forehand stitching techniques.
• Utilizing the curved tip of the needle driver effectively.

VATS Suturing

VATS suturing requires slightly different skills compared to laparoscopic suturing due to significant differences between the two approaches::

• Utility port. In VATS, the size of the utility port combined with the wound retractor allows the needle, already mounted on a needle driver, to be inserted directly into the chest cavity. This eliminates the need for repositioning it inside later, simplifying the process.
• Triangulation. Achieving proper 60° triangulation of instruments in VATS is largely impossible without significantly increasing the number of ports. The shorter distances between the ports and the target area limit the triangulation angle, making laparoscopic bi-manual suturing techniques impractical in most situations.

As a result, VATS suturing is performed through the utility incision, with the needle being brought out of the chest after each stitch. The needle is then remounted onto the needle driver at a convenient angle and reintroduced into the chest to perform the next stitch.

Needle Driver

A needle driver with a curved tip is more versatile but slightly more challenging to control compared to a straight-tip needle driver. The main challenge is to determine the optimal direction of the curved tip in relation to the needle:

• Curved in the direction of the needle.
• Curved away from the tip of the needle.

When the needle is inserted and pushed through the tissue, one direction typically enhances exposure, while the other reduces it.

Direction of the curved tip...

To determine the optimal direction of the tip, it is usually best to test both options and then select the one that provides the best exposure.

Handling the suture

A continuous suture can proceed in two directions relative to the utility port:

• Away. Suturing away from the utility incision requires the free end of the suture to remain in the lower part of the utility port. The needle should be introduced above the suture, and after passing through the parenchyma, it must be brought out of the chest along the uppermost trajectory to avoid creating an unintended mattress stitch.
• Towards. Suturing towards the utility incision requires the opposite approach—keeping the free end of the suture in the upper part of the utility incision and performing the suturing underneath.

Starting point...

Start the suturing closer to the utility port and begin by moving away from it.

In VATS, this approach is typically more challenging due to the limited number of ports. Instead, the suture is usually started in a direction moving away from the surgeon, while the free end of the stitch is pulled through the utility port to provide necessary retraction.

Forehand & Backhand

The surgeon must be proficient in both forehand and backhand stitching techniques. In simple suturing situations on a perfectly horizontal surface, it is advantageous for the needle to exit toward the camera, which is positioned in the lower part of the chest cavity, except in uniportal VATS. The following principles typically apply:

• Right Side. A forehand stitch is generally more convenient.
• Left Side. A backhand stich is preferable.

Suturing vessels

In more complex scenarios, such as suturing a more vertical surface (e.g., vessels or bronchi), it is often most convenient for the needle to exit upward. In such cases, different principles apply when selecting between backhand and forehand techniques

Scoring and Feedback

Continuous suturing is scored based on the following criteria:

• Entrance and Exit. The needle should both enter and exit within the marked square. Touching the line earns ½ point..

Camera

• Horizon. The camera horizon must be leveled within a tolerance of ±10°.
• Target. Both marked squares must be within the inner target scoring area.

Penalties

The following errors result in penalties:

• Multiple Attempts. Repeated attempts to pass the needle through the parenchyma are penalized.
• Tangled Suture. A penalty is applied if the suture becomes tangled, such as forming an unintended mattress stitch.
• Injury. Any injury to the lung is penalized.

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