Chapter 4.18: The Pulley Buried Vertical Mattress Suture

Double buried vertical mattress, dermal buried pulley suture, SICM, modified buried dermal suture

This technique is best used in areas under very significant tension. Wounds under marked tension may be challenging to close even with well-placed buried sutures. The pulley buried vertical mattress suture technique relies on the pulley effect of multiple loops of suture to permit the closure of wounds under even significant tension. In addition, the locking effect of placing a double loop 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. Though 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, 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.

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, critically, 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, steps (1) through (5) are then repeated, after moving proximally toward the surgeon. The second set of loops may be placed 2-6 mm apart depending on the size of the defect, the thickness of the dermis, and the degree of tension on the wound.

7. The suture material is then tied utilizing an instrument tie (Figures 4-18A, 4-18B, 4-18C, 4-18D, 4-18E, 4-18F, 4-18G, 4-18H, 4-18I).

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.

A similar approach may be utilized by surgeons who favor skin hooks over surgical forceps; here again, the hook may be used to hyper-reflect the skin edge back during the first portion of the first bite and then similarly pull the incised wound edge toward the center of the wound during the second portion of the first bite. This will encourage the needle to follow the desired heart-shaped path without necessitating a dramatic twist of the needle driver as the needle changes course.

The apex of the needle should be in the papillary dermis; if the needle courses too superficially, dimpling may occur. While such dimpling is sometimes almost unavoidable, it remains best to avoid it if possible since: (1) patients may sometimes have some concern regarding the immediate postoperative appearance, and (2) dimpling signifies that the suture material traverses very superficially, raising concern that it could be associated with an increased risk of suture spitting.

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. As long as undermining has been carried out effectively, utilizing a pulley technique with a thicker gauge suture material should allow for effective closure of all but the tightest wounds.

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 buried vertical mattress suture closer to the surgeon, this technique can be very simple to learn and is easily reproducible.

As always, the choice of suture material is largely based on the individual surgeon’s preference. Braided absorbable suture material has the advantage of locking more reliably than monofilament, though monofilament suture allows for easier pull through and therefore may facilitate the pulley effect of the double loop of suture material.

In areas under extreme tension, a three-loop variation of this approach is possible as well, allowing for an even more dramatic pulley effect. This benefit must be weighed against the added retained suture material that would be associated with the additional loop.

While the eversion is less pronounced than that seen in other techniques, such as the pulley set-back dermal suture, patients may still be left with a small ridge in the immediate postoperative period.

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 pulley sutures leave two loops of suture material in the skin in lieu of one, 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.