Chapter 4.21: The Half Pulley Buried Dermal Suture

Lateral pulley buried dermal suture, set back pulley 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. It is similar to the half pulley buried vertical mattress suture, but with the extra loop placed at the beginning, rather than the end of the technique.

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 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. 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 required.

2. While reflecting back the dermis, the suture needle is inserted at 90 degrees into the underside of the dermis 4-8 mm distant from the incised wound edge.

3. The first bite, which represents the extra pulley loop, 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 3-4 mm distant from the incised edge, as would be done with a set-back dermal suture. The size of this first loop is based on the size of the needle and the thickness of the dermis, and should be designed as a modestly sized extra loop which will allow for a pulley effect.

4. Keeping the loose end of suture between the surgeon and the patient, the needle is then reinserted again on the same side of the dermis as the first loop, just distal to the entry and exit points of the first loop of suture, but again through the undermined undersurface of the dermis. It should enter approximately 3-8 mm setback from the incised wound edge. The needle then exits at the wound margin as in a simple buried dermal suture.

5. The tissue on the opposite side of the wound is then reflected back in a similar fashion as on the first side, and the third bite is executed by inserting the needle into dermis at the wound edge. This bite should be executed by following the curvature of the needle and avoiding catching the undersurface of the epidermis. It then exits the undersurface of the dermis approximately 3-8 mm lateral to the incised wound margin. This should mirror the second bite taken on the contralateral side of the wound.

6. The suture material is then tied utilizing an instrument tie (Figures 4-21A, 4-21B, 4-21C, 4-21D, 4-21E).

Like the half pulley buried vertical mattress suture, this technique may be conceptualized as a simple buried dermal suture with an additional loop, or as a 1½ loop simple buried dermal pulley suture, though with the extra loop taken at the beginning, rather than at the end of the technique. It is slightly faster to execute than other pulley sutures, 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 pulley buried dermal suture.

This technique is useful when there is significant tension across the wound, and a single buried suture may not hold the edges together.

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 extra loop of suture material.

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 an oblique fashion, though this is not usually seen in practice. Finally, since the additional loop of suture material is located on the side of the first bite, the pulley effect may not be as pronounced as in other pulley techniques, since there is no back-and-forth pulley effect between the two sides of the wound.