Chapter 4.7: The Backing Out Running Subcuticular Suture

Backing out subcuticular suture

This is an epidermal approximation technique suitable for wounds under minimal to no tension in areas with an excellent vascular supply. 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 ineffective in the presence of significant tension.

As with any technique, it is best to utilize the thinnest suture possible for any given anatomic location. Since the backing out subcuticular suture technique is not designed to hold tension, and its utility is limited to fine-tuning epidermal approximation, 5-0 or 6-0 suture is generally adequate when adopting this technique. This is especially important since a large volume of suture material is left in situ when utilizing this approach. It is best to utilize a monofilament suture material to minimize the coefficient of friction at the time of suture removal.

1. 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.

2. 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.

3. 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 earlier mentioned step on the contralateral edge of the incised wound edge.

4. A small amount of suture material is pulled through 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.

5. The same technique is repeated on the contralateral side of the incision line, and alternating bites are then taken from each side of the incision line, with continuing on 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.

6. A small roll of petrolatum gauze (or a dental roll) is then inserted in the space between the apex of the wound and the exit point of the suture material. The needle is then reinserted between the petrolatum gauze and the wound apex, securing the gauze in place and exiting at the interior of the wound.

7. Moving in the opposite direction, steps (1) through (5) are then repeated, with the suture material snaking an alternating course through the superficial dermis, using a backhand technique if desired.

8. After exiting lateral to the apex where the closure began, a roll of petrolatum gauze is again placed between the two ends of the suture and the suture material is tied off (Figures 4-7A, 4-7B, 4-7C, 4-7D, 4-7E, 4-7F, 4-7G, 4-7H, 4-7I, 4-7J).

This is a niche technique, as the addition of a second row of subcuticular suture material in the wound probably does not add significantly to wound security while it doubles the amount of suture material that will ultimately need to be removed.

As with the standard running subcuticular suture, body positioning may be very helpful in maintaining an efficient and comfortable backing out subcuticular technique. Most surgeons are trained to work with the surgical site flat and perpendicular to their body. Since the motions associated with subcuticular suture placement are 90 degrees off from this, it may be useful to stand with the surgeon’s body (shoulder to shoulder) parallel to the incision line. This allows for a flowing motion from right to left without the need to twist the shoulders or wrists.

Since this approach requires the surgeon to perform the second half of the closure moving in the opposite direction, it may be useful to use a backhand technique for many of the suture throws when moving back toward the original wound apex. This may add significantly to the time needed to complete this closure while facility with a backhand technique is improved.

As with the standard running subcuticular approach, a smooth, flowing technique is of paramount importance in executing this technique effectively and efficiently. Some authors have advocated adjusting the angle used to hold the needle in the needle driver from the traditional 90 degrees to 135 degrees to increase the surgeon’s comfort and minimize the need for physical contortion, though adjusting the surgeon’s body position may obviate the need for this adjustment.

Though it may be conceptualized as a bidirectional subcuticular closure, the extra row of sutures in this technique adds little to wound security, as the entire suture line is secured with a single knot. Therefore, it is not recommended as a solitary closure approach, but rather it is best utilized layered over the top of a deeper suturing technique.

This technique results in leaving a very significant quantity of foreign-body material in the dermis in a continuous fashion—essentially twice as much as the running subcuticular technique. While this may not represent a major problem in areas with a thick dermis such as the back, in other anatomical locations the large quantity of suture that is left in situ may result in concerns regarding infection, foreign-body reaction, and even the potential that the suture material itself could present a physical barrier that would impinge on the ability of the wound to heal appropriately—an iatrogenic eschar phenomenon.

The extra row of subcuticular sutures used in this technique raises further concern regarding the possibility of tissue strangulation along the wound margin that could theoretically be associated with tightly placed subcuticular sutures. It, therefore, should be reserved for areas with an outstanding vascular supply, such as the face.

Removal of long-standing suture entails a theoretical risk that a potential space—albeit a thin and long one—is created on the removal of the suture material. This theoretical risk may be mitigated by utilizing the thinnest possible suture material, and this risk is higher in this approach than in the standard subcuticular suturing technique.

There is sometimes a tendency for the apices of the wound to develop exaggerated dog ears due to the tension vector created when looping and tying the suture material over the gauze bolsters lateral to the apices. Minimizing tension across this suture helps minimize this potential issue.