Chapter 4.36: The Buried Tip Stitch

Deep tip stitch

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. The buried variation of the tip stitch can be conceptualized as a low-tension purse-string closure, since it utilizes a mild form of circumferential tissue advancement. 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 5-0 absorbable suture is appropriate. On the extremities and scalp, a 3-0 or 4-0 absorbable suture material may be used, and on the back and shoulders, 2-0 or 3-0 suture material is effective, though care should be taken with leaving the relatively thick 2-0 suture in the superficial dermis, as it may hydrolyze relatively slowly. Monofilament and braided suture materials may both be appropriate when utilizing this technique.

1. The flap is brought into place using buried sutures, allowing the tip to rest with only minimal tension in its desired position. The wound edge of the distal portion of nonflap skin is gently reflected back, permitting visualization of the dermis.

2. The needle is inserted into the underside of the dermis on the far right edge of the distal nonflap section of skin with a trajectory running parallel to an imaginary circle around the point where all three segments of skin will meet. Generally, this entry point in the dermis should be approximately 1-3 mm set-back from the epidermal edge, depending on the thickness of the dermis and the anticipated degree of tension across the tip. The needle, and therefore the suture, should pass through the deep dermis at a uniform depth. Bite size is dependent on needle size, though in order to minimize the risk of necrosis it may be prudent to restrict the size of each bite.

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 repeat the preceding step on the flap tip to the left of the previously placed suture.

4. A small amount of suture material is pulled through and the needle is inserted into the dermis in the flap tip, and the same movement is repeated.

5. The same technique is then repeated on the proximal nonflap edge of skin, keeping the needle parallel to the imaginary circle and moving in the same counterclockwise direction. The needle then exits close to the original entry point on the right side of the wound.

6. The suture material is then gently pulled taut and tied utilizing an instrument tie, burying the knot (Figures 4-36A, 4-36B, 4-36C, 4-36D, 4-36E).

The buried tip stitch is very useful when bringing the tip of a flap into place. 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 buried purse-string approach, it is important to appreciate that the buried 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.

Depending on patient positioning, the three wound edges may be approximated in any order, so that a backhand approach could be used if desired, or the bite through the flap tip could be executed as the first step in a closure. If this is done, however, the knot will be placed directly adjacent to the tip of the flap, which may not be ideal.

A downside of traditional tip stitch placement is the 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 in the standard tip stitch. Therefore, the problem of a depressed tip is not generally seen with the buried tip stitch approach, another significant advantage of this technique.

Since some absorbable suture material is left in the dermis, foreign-body reactions, suture abscess formation, and infections are possibilities. That said, this technique joins only three edges of tissue, and therefore leaves only slightly more suture material in situ than a standard buried suture.

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 together relatively loosely so that the tip is not overly constricted when the knot is tied. Additionally, if the bites of dermis are sufficiently setback 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 buried tip stitch approach likely provides a reasonable balance between tissue approximation and adequate vascular supply.