Chapter 4.28: The Imbrication Suture

This technique is designed for wounds under marked tension, especially those on the scalp and upper forehead. It is a deep tissue support technique, permitting the tension of wound closure to shift from the dermis to the galea or fascia, thereby creating a lower-tension closure that is associated with less scar-spread. Like the fascial plication technique, in addition to tension reduction, this approach also leads to an increase in the apparent length to width ratio of an excised ellipse and improved dead-space minimization.

Suture choice is dependent in large part on location. As this technique is designed to bite the galea or the undersurface of the deep fat, generally a 3-0 (on the scalp), 4-0, or even 5-0 absorbable suture may be used. Since suture material is left deep to the subcutaneous fat, the incidence of suture abscess formation is vanishingly rare.

1. After adequate undermining in the subgaleal (on the scalp and upper forehead) or suprafrontalis (on the lower forehead) plane, and after any lagging fat has been extirpated, the wound edges are reflected back using surgical forceps or hooks.

2. While reflecting back the wound edge, including the galea (or deep fat, as applicable), the suture needle is inserted at 90 degrees into the underside of the deep tissue 4-8 mm distant from the incised wound edge, but medial to the edge of the undermined plane.

3. The first bite is executed by entering the deep tissue and following the curvature of the needle parallel to the wound edge. The suture material may be gently pulled to test that a successful bite of deep tissue has been taken.

4. Keeping the loose end of suture between the surgeon and the patient, attention is then shifted to the opposite side of the wound. The second bite is executed by repeating the procedure on the contralateral side.

5. The suture material is then tied utilizing an instrument tie. Hand tying may be utilized as well, particularly if the wound is deep and the instruments cannot be easily inserted to complete the tie (Figures 4-28A, 4-28B, 4-28C, 4-28D).

This technique is useful for wounds under marked tension, especially for larger defects on the scalp and forehead. If needed, a galeotomy—relaxing incisions through the galea—may be placed parallel to the long axis of the wound to facilitate even greater tissue movement. Like the fascial plication approach, this can therefore be conceptualized as an alternative to pulley sutures that affords both a decrease in tension across the wound surface (by shifting tension from the dermis to the galea) and an increase in the length to width ratio of the ellipse.

Like the fascial plication technique, this approach often leads to a more fusiform defect, even when an oval-shaped excision has been performed. Therefore, it may be useful when attempting to keep a defect as short as possible without dog-ear formation. In cases where this approach is anticipated, it may be worthwhile to create a defect with a length to width ratio of less than 3 to 1, as is traditionally employed, as that may be sufficient to lead to a tapered ellipse.

If possible, a single galeal imbrication suture may be placed at the center of the wound. This balances the benefit of dead-space minimization and tension relief with the desire to minimize suture material piercing the galea that may be associated with a theoretical increase in infection rate.

In large wounds under marked tension, a series of spaced imbrication sutures may be placed as well. Except for the largest wounds, typically no more than three or four sutures are needed to effectively imbricate the underlying galea.

This technique is also useful when large space-occupying lesions, such as pilar cysts, have been excised from the scalp. In these cases, placing dermal sutures alone results in a significant residual dead space that may be associated with a higher risk of hematoma or seroma formation, as well as subsequent infection. Imbrication may serve to help minimize this dead space by pulling deeper structures centrally and thereby filling the potential space.

A double, or pulley, version of this approach is possible as well, that may be useful when the imbricated tissues are under marked tension. As with any pulley approach, this affords a mechanical advantage and allows the imbricated tissues to be drawn together with greater ease. As an added benefit, this also permits immediate locking of the suture material after the first knot throw, which may obviate the need for an assistant in some cases.

It is important that the surgeon have excellent familiarity with the relevant tissue planes when executing deep-tissue imbrication. Since deep tissues are incised, undermined, extirpated, and then imbricated, there is the theoretical potential for damage to an underlying neural or vascular plexus in the course of wound preparation and suturing. As long as meticulous attention is paid to the depth of undermining and the correct tissue planes (subgaleal generally, or suprafrontalis on the lower central forehead), this is not generally a problem, though certainly this technique should not be applied in any of the “danger zones” of the face where damage to the facial nerve, or other vital structures, is possible.

Another possible drawback of this approach is the potential for increased postoperative pain when compared with utilizing dermal sutures alone. While this is not a typical occurrence, depending on how deep the suture material traverses through frontalis muscle, pain may sometimes be experienced that is out of proportion to the defect size and depth.

Since the integrity of the galea has been compromised, there is similarly a theoretically increased risk of infection with this technique. That said, many closures on the scalp and upper forehead, even when placing only dermal sutures, benefit from subgaleal undermining, and therefore this risk is not unique to this technique.

The lateral bites in the undersurface of the galea should be taken no closer than 1-2 mm from the lateral undermined edge of the deep tissue. In addition, for horizontally oriented excisions on the forehead the surgeon may wish to differentially undermine so that a broad area is undermined at the superior portion of the wound but only a relatively narrow area is undermined at its inferior edge. This will aid in avoiding adding a dramatic lift to the lower forehead.