Key Practice Points
Applying the principles of wound closure is key to acceptable wound and scar appearance.
Matching the layers of the wound surfaces with sutures is critical to scar appearance.
Because scar tissue contracts over time, wound edge eversion prevents “pitting” of the scar and eliminates a poor result.
Excessive wound tension, caused by sutures placed too tightly, can cause ischemia of the edges and an increased amount of scar tissue.
Deep sutures become foreign material when buried in a wound. Placing as few deep sutures as possible is recommended to reduce the risk of infection and the risk of an increase in the amount of scar tissue.
“Dead” space is created when the skin of deep wounds is closed without deep or subcutaneous sutures to eliminate the dead space.
The final sutured wound should have all of the knots aligned to one side of the wound. This appearance inspires confidence in the patient and, more important, prevents the knots from interfering with laceration healing.
Each wound and laceration has technical requirements that have to be met to repair a wound effectively. By understanding the basic principles that underlie the technical requisites of wound care, lacerations and wounds can be closed with the best chance for an optimal result. During actual closure, every attempt is made to match each layer evenly and to produce a wound edge that is properly everted. Proper knot-tying technique is paramount to facilitate eversion and to prevent excessive tension on the wound edge. When necessary, dead space is closed, and finally, sutures are spaced and sequenced to provide the best and most gentle mechanical support.
Definition of Terms
Several techniques and maneuvers used in wound care are referred to by terms that can be confusing. These terms are defined so that the reader thoroughly understands the material contained in this chapter.
Bite: A bite is the amount of tissue taken when placing the suture needle in the skin or fascia. The farther away from the wound edge that the needle is introduced into the epidermis, the bigger the bite.
Throw: Each suture knot consists of a series of throws. A square knot is fashioned with two throws. Because of nylon’s tendency to unravel, several additional throws are necessary to secure the final knot when this material is used.
Percutaneous closure (skin closure): Sutures, usually of a nonabsorbable material, which are placed in skin with the knot tied on the surface, are called percutaneous closures. They also are referred to as skin closures. Recent clinical studies have shown that, in certain circumstances such as lacerations of the face and fingertip, absorbable sutures can be used to close skin.
Dermal closure (deep closure): Sutures, usually of an absorbable material, which are placed in the superficial (subcutaneous) fascia and dermis with the knot buried in the wound, are called deep closures.
Interrupted closure: Single sutures, tied separately, whether deep or percutaneous, are called interrupted sutures.
Continuous closure (running suture): A wound closure accomplished by taking several bites that are the full length of the wound, without tying individual knots, is a continuous or running suture. Knots are tied only at the beginning and at the end of the closure to secure the suture material. Continuous closures can be percutaneous or deep.
Basic Knot-Tying Techniques
Several knots can be used to tie sutures during wound closure. The most common is the surgeon’s knot ( Fig. 10-1 ). The advantage of this knot is that the double first throw offers better knot security, and there is less slipping of the suture material as the wound is gently pulled together during tying. The wound edges remain apposed while the second and subsequent single throws are accomplished. The knot-tying sequence shown in Figure 10-1 illustrates the proper instrument technique required to obtain a surgeon’s knot. The instrument tie can be used for almost all knots, whether for deep or superficial closures.
Principles of Wound Closure
When closing a laceration, it is important to match each layer of a wound edge to its counterpart. Superficial fascia has to meet superficial fascia. Dermis to dermis necessarily brings epidermis to epidermis. Failure to appose layers meticulously can cause improper healing with an unnecessarily large scar ( Fig. 10-2 ).
Wound Edge Eversion
Just as important as layer matching is proper wound edge eversion during the initial repair. Because of the normal tendency of scars to contract with time, a wound edge slightly raised above the plane of the normal skin gradually flattens with healing and has a final appearance that is cosmetically acceptable ( Fig. 10-3 ). Wounds that are not everted contract into linear pits that become noticeable cosmetic defects because of their tendency to cast shadows.