This technique is best used in areas under significant tension. The back, shoulders, and thighs are particularly amenable to the set-back technique, though it may be used in almost any location, including the central face and ears. Areas prone to wound inversion, such as the cheek and forehead, may also be well-served utilizing this technique.
Since it is easier to place than a buried vertical mattress suture, this technique may be used by budding surgeons, medical students, and residents as the workhorse technique for deep tension-relieving sutures.
Suture choice is dependent in large part on location, though as 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 buried simple or buried vertical mattress suture. 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. 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.
The wound edge is reflected back using surgical forceps or hooks. Adequate visualization of the underside of the dermis is required.
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.
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.
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.
The second and final 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.
The suture material is then tied utilizing an instrument tie (Figures 4-2A, 4-2B, 4-2C, 4-2D, 4-2E, 4-2F, 4-2G, 4-2H).
Figure 4-2A.
The needle is inserted through the underside of the dermis, exiting again through the underside of the dermis set back from the wound edge.