This is a locking variation of 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.

It is used for three central reasons: (1) To aid in hemostasis, (2) To provide improved eversion over the standard running suture, and (3) To provide equal tension across all loops of the running suture.

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. On the face and eyelids, a 6-0 or 7-0 monofilament suture is useful for epidermal approximation. When the goal of the running locking 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 is useful in areas under moderate tension where the goal of suture placement is relieving tension or hemostasis 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 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, but rather than pulling all of the suture material through after completing the throw, a loop of suture is left from the beginning of the throw, and the needle is then passed through the loop of suture, locking the suture in place.

   
   
6. 
   

   Instead of tying a knot, step (5) is 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 5-4A, 5-4B, 5-4C, 5-4D, 5-4E, 5-4F, 5-4G, 5-4H, 5-4I, 5-4J, 5-4K, 5-4L).