Chapter 4.19: The Half Pulley Buried Vertical Mattress Suture

Dermal buried pulley suture; modified buried dermal suture

This technique is best used in areas under very significant tension, and can be conceptualized as existing on the spectrum between single and double buried vertical mattress sutures. Wounds under marked tension may be challenging to close even with well-placed buried sutures. The half pulley buried dermal suture technique relies on the pulley effect of an additional single loop of suture to permit the closure of wounds under even significant tension. In addition, the effect of placing an extra bite of suture leads the suture material to lock in place after the first throw of the surgical knot, obviating the need for an assistant maintaining the alignment of the wound edges.

Suture choice is dependent in large part on location. Since some suture material traverses the papillary dermis and the incised wound edge, as always the smallest gauge suture material appropriate for the anatomic location should be utilized. On the back and shoulders, 2-0 or 3-0 suture material is effective, though theoretically the risk of suture spitting or suture abscess formation is greater with the thicker 2-0 suture material. This needs to be weighed against the benefit of utilizing a larger CP-2 needle, which will almost never bend even in the thickest dermis, and the benefit of adopting the 2-0 suture material, which is less likely to snap under tension or fail during tension bearing activities, leading to attendant dehiscence. On the extremities, 3-0 or 4-0 absorbable suture material may be used, and on the face and areas under minimal tension, though this technique would only rarely be used, a 5-0 absorbable suture is adequate.

Braided suture tends to lock more definitively than monofilament, though monofilament suture allows for easy pull through when taking advantage of the pulley effect.

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

2. While reflecting back the dermis, the suture needle is inserted at 90 degrees into the underside of the dermis 4 mm distant from the incised wound edge.

3. The first bite is executed by following the needle initially at 90 degrees to the underside of the dermis and then changing direction by twisting the needle driver so that the needle exits in the incised wound edge. This allows the apex of the bite to remain in the papillary dermis while the needle exits in the incised wound edge at the level of the reticular dermis.

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.

5. The second bite is executed by inserting the needle into the incised wound edge at the level of the reticular dermis. It then angles upward and laterally so that the apex of the needle is at the level of the papillary dermis. This should mirror the first bite taken on the contralateral side of the wound.

6. Keeping the tail of the suture material between the surgeon and the first set of loops, the needle is then inserted into the undersurface of the dermis slightly further set-back from the wound edge than the first throw.

7. The needle then exits in the deep reticular dermis, just deep to the exit point of the first loop of suture.

8. With both ends of the suture material now exiting from the same side of the wound (generally the surgeon’s left), the suture material is then tied utilizing an instrument tie (Figures 4-19A, 4-19B, 4-19C, 4-19D, 4-19E, 4-19F).

This technique may be conceptualized as a buried vertical mattress suture with an additional bite, or as a 1½ loop buried vertical mattress pulley suture. It is therefore slightly faster to execute than the pulley buried vertical mattress, since this technique saves one needle throw. That said, since there is one less loop of suture, the pulley effect may similarly be less pronounced, though this needs to be weighed against the theoretical benefit of less retained suture material in this technique than in a double buried vertical mattress suture.

This technique requires some practice to master, though once mastered it is straightforward to execute. The first bite may be finessed by first reflecting the wound edge back sharply during needle insertion and then returning the edge medially after the apex has been reached. This approach helps lead the needle in the correct course without an exaggerated change in direction with the needle driver.

The apex of the needle should be in the papillary dermis; if the needle courses too superficially, dimpling may occur. This technique is useful when there is significant tension across the wound, and a single buried vertical mattress suture may not hold the edges together.

This technique is also very useful when the surgeon needs the first throw of the knot to securely hold the wound edges together, as this technique is able to effectively lock the suture in position after only a single throw. This obviates the need for an assistant’s constant presence in these instances, and permits precise placement of the suture and knot to allow for precise epidermal approximation.

It is critical to keep the suture material deep to the loops of suture when using this technique, as this is the mechanism by which the suture locks in place after the first throw. As long as the surgeon conceptualizes this approach as placing a standard buried vertical mattress suture followed by a second half vertical mattress suture slightly deeper, this technique can be very simple to learn and is easily reproducible.

The extra throw may also be completed with an oblique or near-horizontal orientation, since it is very important that this extra throw bite sufficient dermis to support the tension of the wound. The extra throw may also be executed as a single set-back dermal suture, though doing so may lead to some discrepancy in the depth of the wound edges, necessitating the placement of depth-correcting epidermal sutures.

While the eversion is less pronounced than that seen with other techniques, such as the pulley set-back dermal suture, patients may still be left with a small ridge in the immediate postoperative period. While this is desirable, it is also important to warn patients of this outcome; explaining that the technique is akin to placing a subcutaneous splint may help the patient develop reasonable and realistic expectations and reduce anxiety regarding the immediate postoperative appearance of the wound.

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. Similarly, areas with sebaceous skin, such as the nose, require meticulous avoidance of dimpling which has the potential to persist. 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 this pulley approach leaves an extra single loop of suture material in the skin, this may result in an increased risk of foreign-body reaction, suture spitting, or suture abscess formation. Still, since the bulk of retained suture material is in the knots, rather than in the thrown loops of suture, this theoretical risk may not translate into a real-world problem in most cases.

There is also a theoretical concern that the extra loop of suture could lead to some wound-edge necrosis, particularly if it is oriented in a horizontal fashion, though this is not usually seen in practice. Finally, since the suture material is tied together on one side of the wound, there may be less precise epidermal approximation than is seen with other techniques, such as the pulley set-back dermal suture and the pulley buried vertical mattress.