Indications

Once the wound has been debrided and irrigated, the physician must determine whether it is amenable to closure based on the time since injury, location, availability of tissue for a tension-free suture as well as the level of contamination. The decision in favor of closing the skin or of open wound management depends on the likely success of primary closure, which in turn heavily depends on the surgeon′s experience. Failure of primary closure can lead to even more damage and a worse outcome than open-wound care with delayed or secondary wound closure.

While in general, surgical incisions should always be closed primarily, this does not apply to all wounds not associated with a fracture, although many of them may also be closed primarily ( Fig 10.1-1a–c ). In the past, surgeons have been taught to leave wounds associated with internally fixed fractures open at the time of the first debridement and irrigation. Many surgeons today believe that wounds of open fractures—up to Gustilo type IIIA fracture—may be closed primarily, which is, however, still controversial [1, 2]. Absolute indications and contraindications to primary wound closure are shown in Table 10.1-1 . Relative contraindications to primary closure include human and animal bites—with the exception of facial bites—and the presence of foreign material.

A common scenario is to extend the traumatic wound in order to provide better exposure for the debridement of recesses and the removal of debris, but also for the insertion of implants. In such cases the clean surgical extension may be closed primarily, while the traumatic portion of the wound is often left open for secondary closure.

Systemic factors and associated conditions must also be taken into consideration when deciding whether to close a wound primarily or not (chapter 4.4). These include:

• 
  

  history and mechanism of injury

  
  
• 
  

  associated injuries

  
  
• 
  

  patient age

  
  
• 
  

  vascular status and/or diabetes mellitus

  
  
• 
  

  immune function

  
  
• 
  

  coagulation status.

Questionable viability of adjacent tissues including compartment syndrome should preclude primary closure. This is an important consideration in:

• 
  

  crush or missile injuries

  
  
• 
  

  thermal burns

  
  
• 
  

  electrical injury.

In each of these situations there frequently is an extensive zone of injury beyond the central area of nonviable tissue, and a zone of questionable tissue viability in between (chapter 3, 10.3.3). As a result, in many injuries with underlying muscle damage, serial debridements may be necessary before the extent of the lesion is fully demarked and wound closure can be considered. The degree of contamination, either based on history, mechanism of trauma or examination, is another important variable to assess.

Too much tension on the wound edges is the greatest enemy of primary wound closure. If in doubt, it is often better to leave the wound open and only close it secondarily. A good measure to judge the tension of skin edges is impaired vascular perfusion or lack of capillary refill when tying the sutures, as may best be seen when the skin appears blanched between stitches. Approximation of the subcutaneous fascia (superficial fascia of the fat) may be helpful in order to reduce the tension of a primary skin suture, but depending on the trauma mechanism (eg, avulsion injury) or the region of the body (eg, lower leg) this is not always possible.

Timing

An important factor to include in the decision for primary closure is the time interval since the injury. In general, the likelihood of infection rises with the length of time the wound is left without debridement. Most surgeons believe that wound debridement and irrigation should occur within 6–8 hours, although some would consider 12 hours to be acceptable. The more heavily contaminated the wound, the more important a shorter time to debridement (chapter 7.1) becomes.

Some surgeons believe that no open fracture wound should be closed primarily, but among those who do close open fractures primarily, debridement within the above guidelines is a prerequisite.

Characteristics of suture materials

There are numerous suture materials available for wound closure. These sutures possess many characteristics, among which size, configuration and resorbability are the most important. Size denotes the diameter of the suture material. The accepted surgical practice is to use the smallest diameter suture that will adequately hold the mending wounded tissue. This practice minimizes trauma while the suture is passed through the tissue to effect closure. It also ensures that the minimum mass of foreign material is left in the body. Suture size is stated numerically; as the number preceding the zero in the suture size increases, the diameter of the strand decreases, eg, 4-0 is much smaller than 1-0 or even 1.

Sutures may generally be classified according to the number of strands of which they consist. Monofilament sutures are made of a single strand of material. Because of their simplified structure, they encounter less resistance as they pass through tissues than multifilament suture material consisting of several twisted or braided strands. Although multi-filament strands possess greater tensile strength, pliability, and flexibility, the multitude of filaments of braided sutures may more easily harbor organisms that may cause infection. Sutures may also be classified according to their degradation properties. Sutures that undergo degradation and resorption in tissues are considered resorbable sutures. Sutures that generally maintain their tensile strength and are resistant to resorption are nonresorbable sutures.

As a general rule, resorbable sutures are used for closure of fascial layers, subcutaneous tissue (ie, the approximation of the superficial fascia of the fat), and joint capsules. Nonresorbable sutures are typically used for skin and tendon repair. Synthetic suture materials are resorbed by hydrolysis. Natural suture materials, such as catgut, are resorbed by proteolysis. Monofilament sutures cause less tissue damage. They also resist infection better than braided suture. However, monofilament sutures do not hold a knot as well as braided suture.

Table 10.1-2 shows representative suture types and their characteristics. Needles should be chosen based on the tissue, which is being sutured. Tapered needles are used for easily penetrated tissues, whereas cutting or reverse-cutting needles are used for skin or heavy fascia.

Suture techniques

Wounds are closed in layers, from deep to superficial. Sutures ( Video 10.1-1a–h ) are used to close dead space in a wound and to close the skin. Joint capsules and fascia are usually closed using a simple interrupted suture ( Fig 10.1-2 ), figure-of-eight suture ( Fig 10.1-3 ) or a running suture ( Fig 10.1-4 ). Both fascia and joint capsules should be closed to form a water-tight layer in order to prevent bacteria from gaining access to underlying joints. Tendons may be sutured using a number of different techniques, such as a modified Krakow, Bunnell or any of a myriad of specialty-specific sutures. These sutures have been adequately described in numerous textbooks or specialized manuals and do not need repeating here. Furthermore, there is no set rule that postulates: this layer needs this specific suture technique and this specific suture material. Often, suture techniques and suture material go with the personal preference and experience of the surgeon.

The goal of all these different techniques of suturing the skin is to provide a mechanical closure of the wound without putting too much tension on the wound edges, allowing for uneventful reepithelialization within 24 hours. Excessive tension at the skin edges can compromise local blood supply as well as the healing process, but placing too many sutures may also result in local hypoxia and hence compromise vascularity, making wound closure a balancing act. While appropriate tension on the skin is difficult to judge clinically, signs that there is too much tension on the skin include blanching of the skin between sutures due to a lack of capillary refill, indentation of the suture into the skin, and loosening of the suture. Keep in mind that edema is common after injury or surgery, so the degree of tension on the skin will often increase during the first few days after closure. This should be anticipated when closing a wound. Softtissue edema and contamination of the wound are two major reasons not to use running sutures for skin closure, but rather interrupted sutures. The latter allows to selectively remove some sutures in case of undue tension, hematoma or seroma formation and/or local inflammation and infection, respectively.

Techniques which reduce strain on the dermis without further damaging the blood supply to the skin involve separate closure of deep layers, such as muscle fascia and subcutaneous fascia (ie, superficial fascia of the fat), the use of horizontal ( Fig 10.1-5 ) or vertical mattress (Donati) suture ( Fig 10.1-6 ), and the careful placement of an appropriate number of stitches. A simple buried suture ( Fig 10.1-7a–b ) may be used for the fascia within the subcutaneous tissue or the dermis.

Cutaneous edges may be closed in many ways. The strongest is closure of the deep dermis with a figure-of-eight suture using a resorbable suture (ie, polyglycolic acid) followed by closure of the dermis with intradermal suture ( Fig 10.1-8 ). The least amount of observable scar is created with a running, nonresorbable, intradermal suture with the least inflammatory response (ie, polypropylene) ( Fig. 10.1-8 ). However, this suture does require removal. It is usually recommended to remove the sutures from extremities within 10–14 days. In doubtful cases or specific regions such as the thigh or the calcaneus, removal after 3 weeks is reasonable. A resorbable intradermal suture (ie, poliglecaprone 25) can be used, but involves a prolonged inflammatory phase during suture degradation.

Instead of using Donati-type mattress suture, Allgöwer described a modification called the Allgöwer-Donati suture ( Fig 10.1-9 ), where the opposite skin edge is caught and exited within the dermis. This technique with 3-0 or 4-0 nonresorbable suture material allows to approximate the skin edges at equal level without eversion or bulging, which cosmetically leaves almost invisible scars. The skin edge with the more problematic vascular supply, eg, the side of a flap and not the side of the local skin, is chosen for the intradermal part of the backstitch in order to have the knot lying on the well-perfused side of the wound.

In wounds forming angles—particularly if there is a Tshape—a corner suture ( Fig 10.1-10 ) may be used. A special suture called an over-and–under or far-near-near-far suture ( Fig 10.1-11 ) may be used as a retention suture whenever temporary swelling precludes primary closure. Such sutures must be used with care, since they may exert a tremendous amount of tension on the skin. If swelling does not abate quickly, they may even lead to tissue necrosis. At corners or apices of flaps, it is important to avoid placing sutures, particularly the ones that are on a dermal level, so as not to compromise perfusion. Rather place single sutures at an adequate distance from the corner or apex of the flap. Fine approximation of the corner or apex can be performed with single knots using thin suture material or Steri-Strip™.

Staples, although popular and frequently used, are not considered first choice, if cosmetically nice-looking scars are expected. Their application is quick, but not very precise and removal must occur within a few days in order to avoid a stepladder pattern, which may cause secondary widening or dehiscence of the skin, resulting in ugly scarring.

Small, clean, simple lacerations with minimal retraction may be managed with noninvasive techniques, including suture strips (ie, Steri-Strip™, 3M™, St. Paul MN, USA), mesh and/or cutaneous adhesives, (ie, Prineo^®, Dermabond^®, Johnson & Johnson Medical Ltd., New Brunswick, NY, USA).

When primary closure is not immediately possible, delayed primary closure may be considered. The wound may be conditioned for closure with a synthetic-skin substitute (eg, Epigard^®, Pfizer, New York, NY, USA), which is applied to the wound initially, then removed after swelling abates and primary closure is made.