Chapter 4.12: The Running Set-Back Dermal Suture

Running Kantor suture; running set-back suture

This approach is best used in areas under mild to moderate tension, as it is a running technique that allows rapid placement of multiple buried suture throws. It may be utilized in a variety of anatomic locations, including the face, neck, and extremities. While it may be utilized on the trunk, interrupted set-back sutures are generally more appropriate in this location.

Since it is a running technique, it may be associated with a higher risk of dehiscence, as interruption of the suture material in any point in its course would lead to loss of effectiveness of the entire suture line. Therefore, it is often used in concert with other sutures techniques rather than as a sole closure approach.

Suture choice is dependent in large part on location. Though this technique is designed to bite the deep dermis and remain buried well below the wound surface, the surgeon may choose to utilize a larger gauge suture than would be used for an equivalently placed running simple or running buried vertical mattress suture.

On the extremities, a 3-0 or 4-0 absorbable suture material may be used, and on the face and areas under minimal tension a 5-0 absorbable suture is adequate. While this approach should probably not be routinely utilized on the back, using a 2-0 absorbable suture on the back with this technique results in only vanishingly rare complications, since the thicker suture remains largely on the underside of the dermis, and suture spitting is an uncommon occurrence.

Braided suture material will allow for better locking of the suture in place, though it will also impede the surgeon’s ability to pull suture material through multiple loops, and therefore adequate suture material should be pulled through with each loop. Monofilament absorbable suture material will pull through more easily, though the lower coefficient of friction means that it will easily slide back through the wound and it will therefore not lock in place until tied.

1. The wound edge is reflected back using surgical forceps or hooks. Adequate visualization of the underside of the dermis is required.

2. While reflecting back the dermis, the suture needle is inserted at 90 degrees into the underside of the dermis 2-6 mm distant from the incised wound edge.

3. The first bite is executed by traversing the dermis following the curvature of the needle and allowing the needle to exit closer to the incised wound edge. Care should be taken to remain in the dermis to minimize the risk of epidermal dimpling. The needle does not, however, exit through the incised wound edge, but rather 1-4 mm distant from the incised edge. The size of this first bite is based on the size of the needle, the thickness of the dermis, and the need for and tolerance of eversion.

4. Keeping the loose end of suture between the surgeon and the patient, the dermis on the side of the first bite is released. The tissue on the opposite edge is then reflected back in a similar fashion as on the first side, assuring complete visualization of the underside of the dermis.

5. The second bite is executed by inserting the needle into the underside of the dermis 1-6 mm distant from the incised wound edge. Again, this bite should be executed by following the curvature of the needle and avoiding catching the undersurface of the epidermis that could result in epidermal dimpling. It then exits further distal to the wound edge, approximately 2-6 mm distant from the wound edge. This should mirror the first bite taken on the contralateral side of the wound.

6. A knot is tied using an instrument tie to secure the suture in place. The tail end of the suture is cut with minimal to no tail, and the needle, now attached to suture material that is securely anchored in the dermis, is reloaded.

7. Steps (1) through (5) may then be repeated in pairs, moving toward the surgeon, but without tying additional knots with each throw.

8. Once the end of the wound is reached, the suture material is tied utilizing an instrument or hand tie (Figures 4-12A, 4-12B, 4-12C, 4-12D, 4-12E, 4-12F, 4-12G). The final anchoring knot is tied by leaving a loop on the penultimate throw, and tying the free end of suture material from the final throw to this loop. The ends of the suture are then trimmed.

As with any running buried technique, this approach provides the benefit of permitting rapid placement of a long string of tension relieving sutures. The pulley effect of the multiple throws also permits effective closure of wounds under even marked tension.

That said, it is critical to focus on outstanding knot security, since the entire suture line is held in place by the knots at the beginning and end of the set of suture throws.

Adding an additional tacking knot, when utilizing this approach is an option as well. It may provide additional knot security. Alternatively, one could consider placing an additional knot or leaving a longer suture tail when utilizing this approach.

A theoretical benefit of the running approach is that there is less suture material left in situ, since the bulk of retained absorbable suture material is in the knots; as there are knots only at the beginning and end of the row of sutures, this technique theoretically decreases the risk of suture spitting and suture abscess formation. Still, the set-back approach leaves suture material deep to the undersurface of the dermis, and therefore the risk of suture spitting and suture abscess formation is negligible.

This is an easy to execute running buried suture approach; since the suture follows the arc of the needle on the undersurface of the dermis there is no need to change planes, effect a heart-shaped suture placement, or guarantee that the suture exit point is precisely at the inside edge of the lower dermis, as may be needed with the running buried vertical mattress suture.

Accurate suture placement is predicated on having a sufficiently undermined plane, since the entire suture loop lays on the undersurface of the dermis. Therefore, broad undermining is a prerequisite for utilizing this technique, since each throw of the needle begins 2-6 mm distant from the incised wound edge on the undermined undersurface of the dermis.

Suture throws may be placed closer together toward the higher-tension areas at the center of the wound to permit greater mechanical advantage and to allow the pulley effect to have a more profound impact at the center of the wound. The throws may then be spaced farther apart toward the apices where the pulley effect is neither needed nor desired, allowing minimization of the quantity of retained buried absorbable suture material left in the wound.

The main drawback of this approach is the same as with any running buried suture. The integrity of the entire suture line rests on the quality of the knots at each end of the row of sutures. Therefore, attention to detail when tying these knots is of paramount importance.

This approach should therefore not be used as a solitary closure technique, but rather may be used deep to interrupted transepidermal sutures or superficial to fascial plication sutures, to afford greater redundancy and add to the resilience of the closure.

The running set-back dermal approach creates significant wound eversion, and the degree of eversion elicited by this approach may, depending on how far set-back the dermal bite is taken, elicit significantly more wound eversion than even the running buried vertical mattress technique.

Patients should be cautioned that they might develop a significant ridge in the immediate postoperative period. Depending on the suture material used and the density of the sutures, this ridge may last from weeks to months.

Epidermal dimpling will occasionally occur where the arc of the suture reaches its apex at the dermal-epidermal junction; on the face and areas with thin dermis this should be assiduously avoided. In truncal areas or those with thick dermis, however, a small degree of dimpling will resolve with time as the absorbable sutures are gradually resorbed. Since tension is distributed broadly across multiple suture loops, the dimpling is not usually overly pronounced, as the tension averages across multiple throws and therefore it is less likely that any one area will yield marked dimpling.