Chapter 4.10: The Percutaneous Horizontal Mattress Suture

Buried horizontal mattress suture

As with other percutaneous approaches, this technique is designed to allow for excellent tension relief while concomitantly permitting easy suture placement in relatively tight spaces. It is best suited to areas with thicker dermis, though it may also be utilized in any body area when tension-relieving sutures must be placed and where insertion of the full needle is challenging.

Suture choice is dependent in large part on location. Though suture material travels percutaneously, exiting the epidermis and then reentering, 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, particularly where the material has exited the epidermis entirely. 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.

1. The wound edge is reflected back using surgical forceps or hooks. In areas under marked tension, or where full visualization is not possible, the needle may be blindly inserted from the undermined space.

2. The suture needle is inserted perpendicular to the incision line at a 90-degree angle into the underside of the dermis 4 mm distant from the incised wound edge.

3. The first bite is started by following the needle and traversing from the underside of the dermis in the undermined space and passing entirely through the dermis and exiting the skin.

4. The needle is then reloaded onto the needle driver and inserted through the epidermis either directly through the same hole as the suture followed during exit, or just distal to it, with the needle-oriented parallel to the incision line. A shallow bite is taken, staying in the superficial dermis, exiting on the same side of the incision line distal to the entry point.

5. The needle is then reloaded and inserted into the same hole or just medial to it, while being held perpendicular to the incision line. The needle should travel through the full thickness of the skin, exiting on the undersurface of the undermined dermis.

6. The needle is then reloaded and enters the undersurface of the undermined dermis on the contralateral wound edge, exiting through the surface of the epidermis. This step may be combined with the prior step and the needle can be inserted into the contralateral wound edge while it is still loaded from the initial pass.

7. The needle is then loaded and inserted either through the same hole or just proximal to it, oriented parallel to the incision line but in the opposite direction as in step 4, following a superficial course and exiting on the same side of the incision line proximal to the incision entry point.

8. The needle is then reloaded in a standard fashion and inserted either through the same hole or just medial to it perpendicular to the incision line, exiting on the undersurface of the undermined dermis.

9. The suture material is then tied utilizing an instrument tie (Figures 4-10A, 4-10B, 4-10C, 4-10D, 4-10E, 4-10F, 4-10G, 4-10H, 4-10I, 4-10J).

This technique is best for use in areas where placement of a traditional buried suture is challenging due to limited space, such as the scalp and lower leg. Even after using small semicircular needles and with extensive undermining, it may be difficult to insert the body of needle into the undersurface of the dermis in these anatomic locations.

This approach may also be used when it is difficult to visualize the undersurface of the dermis, since the needle throws may be placed in an almost blind fashion. The skin is grasped gently to make it taught and the needle is inserted through the undermined space, exiting on the outside of the skin. This may be executed by feel, an approach well suited to the scalp where minimal dermal elasticity precludes full exposure of the undersurface of the undermined dermis. The ear is another area where this approach may be very useful, since the limited elasticity of the thin dermis on the helix may make placement of traditional vertically oriented buried sutures challenging.

Since suture material exits the skin and then reenters, dimpling may occur. Patients should be warned that this is expected and will resolve with time, though residual dyspigmentation is certainly possible. Reentering the skin through the same hole may help minimize the risk of dramatic dimpling.

Setting back the first throw far from the incised wound edge may result in over-eversion; the chief drawback of over-eversion is that the dermis may overhand in the center of the incised wound edge, barring the epidermal edges from approximating appropriately, leading to a slightly wider final scar. This may be easily solved by carefully beveling the dermis to allow the epidermal edges to meet unimpeded.

Theoretically, horizontally oriented sutures may confer a slightly increased risk of epidermal-edge necrosis, since suture material has the potential to constrict the small vessels supplying the wound margin. That said, this complication is rarely seen in practice as long as the bite size is not overly large and suture material is not tied with excessive tension.