This is an epidermal approximation technique suitable for wounds under minimal to no tension. This technique should almost never be employed in the absence of a deep dermal suture, since its strength is in fine-tuning epidermal approximation and it is less effective in the presence of significant tension. Its use is also predicated on the presence of a relatively robust dermis, since it is a primarily intradermal technique and therefore does not recruit any strength from the epidermis. Therefore, it should be avoided in the context of atrophic skin or in areas with a very thin dermis, such as the eyelids.
As with any technique, it is best to utilize the thinnest suture possible for any given anatomic location. The subcuticular suture technique is not designed to hold tension irrespective of anatomic location. Since its utility is limited to fine-tuning epidermal approximation, 5-0 or 6-0 suture is often useful when adopting this technique.
Depending on the chosen technique variation, this technique may be used with either absorbable to nonabsorbable suture. If nonabsorbable suture is used, it is best to utilize a monofilament suture material to minimize the coefficient of friction when removing the suture. Since a relatively large amount of suture material will be left in the superficial dermis, if absorbable material is used then utilizing a nonbraided monofilament suture may be best to minimize the risk of infection and foreign body reaction.
The needle is inserted at the far right corner of the wound, parallel to the incision line, beginning approximately 2-5 mm from the apex. The needle is passed from this point, which is lateral to the incision apex, directly through the epidermis, exiting into the interior of the wound just medial to the apex. Note that this first pass may be finessed depending on the technique used for finishing the closure, as addressed in detail below.
With the tail of the suture material resting lateral to the incision apex and outside the wound, the wound edge is gently reflected back and the needle is inserted into the dermis on the far edge of the wound with a trajectory running parallel to the incision line. The needle, and therefore the suture, should pass through the dermis at a uniform depth. Bite size is dependent on needle size, though in order to minimize the risk of necrosis it may be prudent to restrict the size of each bite. The needle should exit the dermis at a point equidistant from the cut edge from where it entered.
The needle is then grasped with the surgical pickups and simultaneously released by the hand holding the needle driver. As the needle is freed from the tissue with the pickups, the needle is grasped again by the needle driver in an appropriate position to repeat the above step on the contralateral edge of the incised wound edge.
A small amount of suture material is pulled through, the skin of the contralateral wound edge is reflected back, and the needle is inserted into the dermis on the contralateral side of the incised wound edge and the same movement is repeated. The needle should enter slightly proximal (relative to the wound apex where the suture line began) to the exit point, thus introducing a small degree of backtracking to the snake-like flow of the suture material. This will help reduce the risk of tissue bunching.
The same technique is repeated on the contralateral side until the end of the wound is reached. At this point, the needle is inserted from the interior of the wound in line with the incision line and exits just lateral to the apex of the wound (Figures 4-6A, 4-6B, 4-6C, 4-6D, 4-6E, 4-6F, 4-6G, 4-6H, 4-6I, 4-6J).
Figure 4-6C.
Overview of the running subcuticular technique.