Chapter 4.4: The Buried Horizontal Mattress Suture

Fully buried horizontal mattress suture

This is a niche technique, useful when closing narrow wounds or those where there is limited space to insert the needle driver, and when placing a buried suture is desirable. It may be employed in a variety of locations, including the scalp, ears, and lower leg, though it has been applied broadly and may be utilized in any number of anatomic locations.

This technique results in adequate wound eversion; depending on how far back the bites are taken and whether the incised wound edge is cut with an inward bevel, it may result in only modest wound-edge approximation.

As always, suture material choice depends on preference and location; while the suture material remains on the undersurface of the dermis, it does traverse the midpapillary dermis, and therefore care should be taken to utilize the smallest caliber of suture that provides adequate tensile strength. Similarly, the knot remains relatively superficial at the level of the reticular dermis, confirming the need to utilize the finest suture available.

This approach should only rarely be used in areas with a thick dermis and under marked tension, such as the chest and back. On the extremities, a 4-0 absorbable suture material may be used, and on the face and areas under minimal tension a 5-0 absorbable suture is adequate. A 3-0 caliber suture may be used on areas such as the lower legs if needed, though this should be utilized with caution as the larger caliber suture material has more of a tendency to spit or result in foreign body reactions.

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 into the undersurface of the dermis parallel to the incision line just lateral to the incised wound edge.

3. The first bite is executed by placing gentle pressure on the needle so that it enters the papillary dermis and then relaxing pressure to permit the needle to exit on the undersurface of the 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 and final bite is executed by inserting the needle into the undersurface of the dermis on the contralateral side, with a backhand technique if desired, and completing a mirror-image loop, so that the needle exits directly across from its original entry point on the contralateral side.

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

This technique is useful for narrow or shallow wounds, such as those on the scalp and shins. It may also be used when adding an additional buried suture in an otherwise largely closed wound, where there is insufficient space to insert a vertically oriented buried suture in the narrow space between two other already-placed sutures.

As with the buried vertical mattress approach, 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, though the needle is oriented parallel to the incised wound edge, as opposed to the perpendicular approach utilized with the buried vertical mattress.

The needle driver may also be held like a pencil, and the needle may then be rotated through the dermis while reflecting back with the forceps to permit easy visualization.

As with any buried technique, the apex of the needle should be in or deep to the papillary dermis; if the needle courses too superficially, dimpling may occur.

This technique should not be adopted in all areas, and there are generally better options for use in areas with a robust dermis under moderate to marked tension, such as the back and shoulders. In those locations, the buried horizontal mattress approach should only be utilized for inserting additional sutures in between already placed buried sutures, when there is insufficient space to place a set-back dermal suture or buried vertical mattress suture.

While the eversion is less pronounced than other techniques, such as the 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.

Wound-edge necrosis has been raised as a potential risk of horizontally oriented suture placement, but in practice this is only encountered very rarely and as a complication of tightly placed traditional horizontal mattress sutures, rather than with the buried equivalent. This is likely due to a constrictive effect on the incised wound edge, which is not typically seen with buried sutures.

The original description of this approach bears some resemblance to the butterfly suture; keeping in mind that the buried horizontal mattress suture should represent a buried version of the traditional horizontal mattress approach, however, the needle entry and exit points should both be in the undersurface of the dermis just lateral to the incised wound edge, as opposed to the butterfly suture where entry and exit occur at the juncture of the incised wound edge and the undersurface of the dermis and where the needle arcs on a diagonal.