Chapter 5.3: The Simple Running Suture

This is the standard running suture used for epidermal approximation. It may be used alone in the context of small wounds under minimal to no tension, such as those formed by a traumatic laceration. It is generally used as a secondary layer to aid in the approximation of the epidermis when the dermis has been closed using a dermal or other deep suturing technique.

With all techniques, it is best to use the thinnest suture possible in order to minimize the risk of track marks and foreign-body reactions. Suture choice will depend largely on anatomic location and the goal of suture placement. Simple running sutures may be placed with the goal of (1) accomplishing epidermal approximation in a wound under mild to moderate tension, such as a laceration, or, more frequently, (2) fine-tuning the epidermal approximation of a wound where the tension has already been shifted deep utilizing a deeper dermal or fascial suturing technique.

On the face and eyelids a 6-0 or 7-0 monofilament suture is useful for epidermal approximation. When the goal of the simple running suture layer is solely epidermal approximation, 6-0 monofilament may be used on the extremities as well. Otherwise, 5-0 monofilament suture material may be used if there is minimal tension, and 4-0 monofilament suture may be utilized in areas under moderate tension where the goal of suture placement is relieving tension as well as epidermal approximation.

1. The needle is inserted perpendicular to the epidermis, approximately one-half the radius of the needle distant to the wound edge. This will allow the needle to exit the wound on the contralateral side at an equal distance from the wound edge by simply following the curvature of the needle.

2. With a fluid motion of the wrist, the needle is rotated through the dermis, taking the bite wider at the deep margin than at the surface, and the needle tip exits the skin on the contralateral side.

3. The needle body is grasped with surgical forceps in the left hand, with care being taken to avoid grasping the needle tip, which can be easily dulled by repetitive friction against the surgical forceps. It is gently grasped and pulled upward with the surgical forceps as the body of the needle is released from the needle driver. Alternatively, the needle may be released from the needle driver and the needle driver itself may be used to grasp the needle from the contralateral side of the wound to complete its rotation through its arc, obviating the need for surgical forceps.

4. The suture material is then tied off gently, with care being taken to minimize tension across the epidermis and avoid overly constricting the wound edges. This forms the first anchoring knot for the running line of sutures. The loose tail is trimmed, and the needle is reloaded.

5. Starting proximal to the prior knot relative to the surgeon, steps (1) through (3) are then repeated.

6. Instead of tying a knot, steps (1) through (3) are then sequentially repeated until the end of the wound is reached.

7. For the final throw at the inferior apex of the wound, the needle is loaded with a backhand technique and inserted into the skin at a 90-degree angle in a mirror image of the other throws, entering just proximal to the exit point relative to the surgeon on the same side of the incision line and exiting on the contralateral side.

8. The suture material is only partly pulled through, leaving a loop of suture material on the side of the incision opposite to the needle.

9. The suture material is then tied to the loop using an instrument tie (Figures 5-3A, 5-3B, 5-3C, 5-3D, 5-3E, 5-3F, 5-3G, 5-3H, 5-3I).

As with the simple interrupted suture, it is important to enter the epidermis at 90 degrees, allowing the needle to travel slightly laterally away from the wound edge before fully following the curvature of the needle when utilizing this technique. This will allow for maximal wound eversion and accurate wound-edge approximation.

The simple running suture is generally used layered over the top of another suture in order to fine-tune epidermal approximation. For example, if set-back dermal sutures were placed to facilitate eversion, occasionally the wound edges may not be fully approximated. A layer of simple running sutures, may be used to solve this problem and effect accurate approximation of the wound edges.

Care should be taken to avoid skimming the needle superficially beneath the epidermis. This results from failing to enter the skin at a perpendicular angle and failing to follow the curvature of the needle. This may result in wound inversion as the tension vector of the shallow bite pulls the wound edges outward and down.

In order to maintain uniformity in the length of the visible running sutures and to allow the suture loops to remain parallel, it is important to take uniform bites with each throw of the simple running suture technique. Therefore, each subsequent loop should begin at the same point lateral to the incised wound edge and at a uniform distance closer to the surgeon than the preceding entry point.

Some surgeons prefer to finesse their running closures so that the loops of suture appear to run perpendicular to the incision line. This approach, however, requires that each loop of running suture be placed at a uniform angle across the incised wound edge, rather than perpendicular to the incised wound edge. Since this affects the force vectors across the wound, and since a row of parallel diagonally oriented sutures is also aesthetically pleasing, this approach is a reasonable option but is not necessary.

It is critical to permit sufficient laxity between the epidermis and the suture material when using this technique in order to minimize the risk of track marks or an exaggerated inflammatory response. Recalling that this technique is designed exclusively for epidermal approximation, and that some postoperative wound edema is expected, will help with conceptualizing the need to keep the throws of suture material loose.

The central drawback of this approach is that, as with all running techniques, the integrity of the entire suture line rests on two knots. Moreover, suture material compromise at any point may lead to a complete loss of the integrity of the line of sutures. Since this technique is designed for low-tension environments, however, even in the face of suture material breakage the remaining throws of suture may permit some residual epidermal approximation.

Since all loops of suture are placed in succession, this technique does not permit the same degree of fine-tuning of the epidermal approximation as a simple interrupted suture. This must be weighed against the benefit of the increased speed of placement of a line of running sutures versus interrupted suture placement, where each throw is secured with its own set of three or more knots.

Moreover, since each loop of the running suture material is designed to hold an equal amount of tension, it follows that areas of the wound under greater tension, such as its central portion, may tend to gape or potentially exist under greater tension leading to an increased risk of track marks.

With any suturing technique, knowledge of the relevant anatomy is critical. When placing simple running sutures it is important to recall that the structures deep to the epidermis may be compromised by the passage of the needle and suture material. For example, the needle may pierce a vessel leading to increased bleeding.

Similarly, particularly if the knot is tied relatively tightly, structures deep to the defect may be constricted. This can lead to necrosis due to vascular compromise or even, theoretically, superficial nerve damage; again, this risk may be mitigated by maintaining some laxity in the suture throws.

This technique may elicit an increased risk of track marks, necrosis, inflammation, and other complications when compared with techniques that do not entail suture material traversing the scar line, such as buried or subcuticular approaches. Therefore, sutures should be removed as early as possible to minimize these complications, and consideration should be given to adopting other closure techniques in the event that sutures will not be able to be removed in a timely fashion.