Chapter 5.22: The Tip Stitch

Half-buried horizontal mattress suture

This technique is designed to bring three ends of tissue together, and is often used in the context of a flap, where it permits the tip of tissue to be inset. It is also utilized to repair V-shaped lacerations. This approach may be conceptualized as a half-buried horizontal mattress suture. 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 its desired position.

2. The needle is inserted into the distal edge of the distal nonflap section of skin at 90 degrees with a trajectory running toward the planned entry point in the tip.

3. The needle is then grasped with the surgical pickups and simultaneously released by the hand holding the needle driver. As the needle is freed from the tissue with the pickups, the needle is grasped again by the needle driver in an appropriate position to place the next throw.

4. The needle is inserted into the distal portion of the tip at the level of the superficial dermis, which should be the same depth at which it exited in the prior step. Keeping the needle running horizontally, parallel with the skin surface, it is rotated through the dermis of the tip, exiting on the proximal side of the tip at the same depth.

5. The needle is then reloaded in a backhand fashion and inserted into the dermis of the proximal nontip section of skin, exiting, parallel to its initial entry point.

6. The suture material is then gently tied utilizing an instrument tie. Care should be taken to minimize tension on this suture to mitigate the risk of flap tip necrosis (Figures 5-22A, 5-22B, 5-22C, 5-22D, 5-22E, 5-22F, 5-22G).

The tip stitch is very useful when bringing the tip of a flap into place, and is used frequently in this situation. Importantly, 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 half-buried horizontal mattress, it is important to appreciate that the 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.

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.

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.

There is sometimes a tendency for the tip to sit deeper than the surrounding tissues. This may be related to the relative upward pull on the nontip sections of skin by the transepidermal sutures.

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.