Chapter 5.24: The Hybrid Mattress Tip Stitch

Vertical mattress tip stitch

This technique is designed to bring three ends of tissue together, and is used in the context of a flap or M-plasty, where it permits the tip of tissue to be inset. This approach may be conceptualized as a hybrid mattress suture that encompasses the dermis of the tip of suture in its near-near step. Since it is used only when attempting to approximate three segments of skin, it is a niche technique.

Suture choice is dependent in large part on location, though as always the smallest gauge suture material appropriate for the anatomic location should be utilized. On the face, where this technique may be used for flap repairs, a 6-0 or 7-0 monofilament nonabsorbable suture is appropriate. On the trunk, extremities, and scalp, a 3-0 or 4-0 nonabsorbable suture material may be used. Fast-absorbing gut may also be used, obviating the need for suture removal but increasing the risk of tissue reactivity.

1. The flap is brought into place using buried sutures, allowing the tip to rest with only minimal tension in or close to its desired position.

2. Starting approximately 4 mm distal from the point where the flap tip will be inset, the needle is inserted perpendicular to the epidermis, approximately 6 mm distant to the wound edge.

3. With a fluid motion of the wrist, the needle is rotated through the dermis, taking the bite wider at the deep margin than at the surface, and the needle tip exits the skin on the contralateral side. If the needle radius is too small to complete this arc in one movement, this first step may be divided into two, with the needle first exiting between the incised wound edges and then reloaded and reinserted to exit on the contralateral side.

4. The needle body is grasped with surgical forceps in the left hand, with care being taken to avoid grasping the needle tip, which can be easily dulled by repetitive friction against the surgical forceps.

5. The needle is then reloaded in a backhand fashion and inserted at 90 degrees perpendicular to the epidermis approximately 3 mm from the wound edge on the same side of the incision line as the exit point, distal from the exit point relative to the surgeon so that it is approximately 2 mm proximal to the flap tip.

6. The needle is rotated superficially through its arc, exiting in the undermined space.

7. The needle is then reloaded, again in a backhand fashion, and a modest bite of the dermis in the flap tip is taken. The needle moves parallel to the skin surface and does not penetrate the epidermis of the tip.

8. The needle is then again reloaded in a backhand fashion and is inserted into the superficial dermis on the contralateral side, exiting through the epidermis similarly to steps (5) and (6).

9. The suture material is then tied off gently, with care being taken to minimize tension across the epidermis and avoid overly constricting the wound edges. Care should be taken to minimize tension on this suture to mitigate the risk of flap tip necrosis (Figures 5-24A, 5-24B, 5-24C, 5-24D, 5-24E, 5-24F, 5-24G).

The hybrid mattress tip stitch is very useful when bringing the tip of an M-plasty into position. Importantly, as with the standard tip stitch, this technique is designed to gently approximate the tissues so that the flap is properly inset in the surrounding skin. While it bears a technical resemblance to the hybrid mattress, it is important to appreciate that the hybrid mattress tip stitch is not designed to work under significant tension, as tension across the suture may lead to necrosis of the delicate and lightly vascularized tip of the flap.

As with the tip stitch, placing set-back dermal sutures, imbrication sutures, or suspension sutures prior to placement of the tip stitch will ensure that the tip itself is not under tension when it is approximated with the surrounding skin.

Note that the near-near step incorporating the flap tip bite is taken just proximal to the tip of the flap, while the initial far-far bite is taken distal to the flap tip. The sling-like effect of this approach forces the tip into place, securing it in its desired position.

The vertical mattress component of this approach helps mitigate the risk of flap tip inversion, an occasional drawback of the standard tip stitch technique.

As with all tip stitch techniques, flap tip necrosis is the greatest risk with this technique, since suture material traverses the dermis containing the tip’s vascular supply. This risk may be mitigated by tying the suture relatively loosely so that the tip is not overly constricted when the knot is tied. Additionally, if the bites of dermis are sufficiently set-back from the wound edge, a small bite comprising less than half of the dermis in the tip could be taken. This would allow blood supply to the tip even in the context of a relatively tight loop running through the distal flap.

Finally, while flap tip necrosis is a risk, studies have suggested that the tip stitch provides less vascular constriction than other options, such as placing two vertically oriented sutures at the edges of the tip or a suture directly through the tip itself. Vascular compromise and ensuing necrosis of the flap tip is always a risk, even if no sutures are placed through the tip itself, and therefore the tip stitch approach likely provides a reasonable balance between tissue approximation and adequate vascular supply.