Overview
Rapid covering and
healing of both acute skin defects and chronic skin defects are
important objectives for wound healing. The best way to heal a wound is
to close it according to surgical standards as quickly as possible after
injury. However, this procedure is limited to those wounds and those
anatomical regions that allow both excision and adaptation of wound
borders to close the wound by primary intention or per primam (Latin term meaning to close the wound by suturing [or equivalent method] and restructuring of the skin continuity).
In large-surface and deep wounds in which the primary wound closure is not possible or not practicable, the most important issue is to dress the wound with appropriate materials to allow the following: (1) to keep the wound free of infection, (2) to reduce or eliminate pain, (3) to reduce or eliminate all potential factors inhibiting natural healing (eg, dead tissue in burns, superficial fibrosis, necrotic tissue), and (4) to replace or substitute the missing tissue as much as possible.
Autologous skin grafting in the form of split- or full-thickness skin is still a criterion standard. However, in many patients, this technique may not be practicable for a variety of reasons, and the wound must be allowed to heal by second intention. Moreover, in cases in which skin grafts are used, a new wound is created on the donor side. Thus, eliminating a new wound to close the old one and to close as many tissue defects as possible without the risk of large area infection, necrosis, tissue hypertrophy, and contraction, as well as deformation of wound borders, is a necessity. The next important problem is to reduce or eliminate scar formation, particularly in the field of large-surface wounds.
Traditional management of large-surface or deep wounds involves open and closed methods. In the open method, the wounds are left in a warm, dry environment to crust over, whereas, in the closed method, wounds are covered with different kinds of temporary dressings and topical treatment, including antibiotics, until healing by secondary intention. The early removal of the dead tissue (eg, in burns) reduced pain, the number of surgical procedures, and the length of the hospital stay.
The surgical intervention (ie, tangential excision of partial- or full-thickness wound) followed by wound closure with autografts or temporary dressings is one of the currently used methods. In large-surface, full-thickness wounds, the wound can be excised down to the fat or the fascia, particularly if infection is present. Excision to the fat induces the removal of the subdermal plexus of blood vessels and decreases the take of autografts because this tissue is less vascularized. Excision down to the fascia induces better take of the autografts but has aesthetic disadvantages.
Wound debridement can also be achieved by enzyme digestion of the dead tissues. Proteolytic enzymes (eg, collagenases used topically) allow a more specific destruction of necrotic tissues, while preserving viable dermis and avoiding blood loss, but the treatment can be painful and can increase the risk of local infection. In addition, it takes a long time to achieve a clean wound bed.
Conventional autograft (epidermis and a significant amount of dermis) obtained from healthy skin areas is considered the optimum wound cover in that its viability yields immediate take (incorporation into the wound bed) and resistance to wound infection. However, harvesting of autograft creates a second wound in the healthy tissue, a donor wound. This open wound increases the risk of infection and fluid/electrolyte imbalance. Repeated conventional harvests of autograft from a donor wound site can result in contour defects or scarring. Optimizing the healing of both main wounds and donor wounds becomes a later goal of patient management and the development of different surgical dressings, which can be used based on the principle of phase-adapted wound healing.
Most recently, developed wound dressings are in use only as temporary dressings because of their synthetic or chemical components, limited persistence on the wound surface, and foreign body character.
Primary closure versus second-intention treatment of skin punch biopsy sites was evaluated in a randomized trial.[1] Punch biopsy sites healed by second intention appear at least as good as biopsy sites closed primarily with sutures. Volunteers preferred suturing for 8-mm biopsy sites and had no preference for 4-mm sites. Elimination of suturing of punch biopsy wounds results in personnel efficiency and economic savings for both patients and medical institutions.
The wounds had been dressed with petroleum jelly under an occlusive dressing that consisted of gauze covered by a transparent dressing (Tegaderm; 3M, St Paul, Minn) and were left in place for 3 days. After that time, the gel foam was removed from the second-intention site and both biopsy sites were cleansed with water to remove any exudate. Then, an occlusive transparent dressing was reapplied to both sites. After this initial dressing change, dressings were changed weekly or more often at the volunteers' discretion until the biopsy sites were completely healed or reepithelialized. Efficient wound dressings can be important for both small and large wounds.
Some of the currently available surgical dressings used in dermatologic and dermatosurgical practice are discussed.
In large-surface and deep wounds in which the primary wound closure is not possible or not practicable, the most important issue is to dress the wound with appropriate materials to allow the following: (1) to keep the wound free of infection, (2) to reduce or eliminate pain, (3) to reduce or eliminate all potential factors inhibiting natural healing (eg, dead tissue in burns, superficial fibrosis, necrotic tissue), and (4) to replace or substitute the missing tissue as much as possible.
Wound repair
Wound repair involves the timed and balanced activity of inflammatory, vascular, connective tissue, and epithelial cells. All of these components need an extracellular matrix to balance the healing process. Skin wounds heal by the formation of epithelialized scars of different contraction ability rather than by the regeneration of a true full-thickness tissue. To minimize scar formation and to accelerate healing time, different wound dressings and different techniques of skin substitution have been introduced in the last decades.Autologous skin grafting in the form of split- or full-thickness skin is still a criterion standard. However, in many patients, this technique may not be practicable for a variety of reasons, and the wound must be allowed to heal by second intention. Moreover, in cases in which skin grafts are used, a new wound is created on the donor side. Thus, eliminating a new wound to close the old one and to close as many tissue defects as possible without the risk of large area infection, necrosis, tissue hypertrophy, and contraction, as well as deformation of wound borders, is a necessity. The next important problem is to reduce or eliminate scar formation, particularly in the field of large-surface wounds.
Traditional management of large-surface or deep wounds involves open and closed methods. In the open method, the wounds are left in a warm, dry environment to crust over, whereas, in the closed method, wounds are covered with different kinds of temporary dressings and topical treatment, including antibiotics, until healing by secondary intention. The early removal of the dead tissue (eg, in burns) reduced pain, the number of surgical procedures, and the length of the hospital stay.
The surgical intervention (ie, tangential excision of partial- or full-thickness wound) followed by wound closure with autografts or temporary dressings is one of the currently used methods. In large-surface, full-thickness wounds, the wound can be excised down to the fat or the fascia, particularly if infection is present. Excision to the fat induces the removal of the subdermal plexus of blood vessels and decreases the take of autografts because this tissue is less vascularized. Excision down to the fascia induces better take of the autografts but has aesthetic disadvantages.
Wound debridement can also be achieved by enzyme digestion of the dead tissues. Proteolytic enzymes (eg, collagenases used topically) allow a more specific destruction of necrotic tissues, while preserving viable dermis and avoiding blood loss, but the treatment can be painful and can increase the risk of local infection. In addition, it takes a long time to achieve a clean wound bed.
Wound coverings
Currently available wound coverings can be divided into 2 categories: (1) permanent coverings, such as autografts, and (2) temporary coverings, such as allografts (including de-epidermized cadaver skin and in vitro reconstructed epidermal sheets), xenografts (ie, conserved pig skin), and synthetic dressings.Conventional autograft (epidermis and a significant amount of dermis) obtained from healthy skin areas is considered the optimum wound cover in that its viability yields immediate take (incorporation into the wound bed) and resistance to wound infection. However, harvesting of autograft creates a second wound in the healthy tissue, a donor wound. This open wound increases the risk of infection and fluid/electrolyte imbalance. Repeated conventional harvests of autograft from a donor wound site can result in contour defects or scarring. Optimizing the healing of both main wounds and donor wounds becomes a later goal of patient management and the development of different surgical dressings, which can be used based on the principle of phase-adapted wound healing.
Most recently, developed wound dressings are in use only as temporary dressings because of their synthetic or chemical components, limited persistence on the wound surface, and foreign body character.
Primary closure versus second-intention treatment of skin punch biopsy sites was evaluated in a randomized trial.[1] Punch biopsy sites healed by second intention appear at least as good as biopsy sites closed primarily with sutures. Volunteers preferred suturing for 8-mm biopsy sites and had no preference for 4-mm sites. Elimination of suturing of punch biopsy wounds results in personnel efficiency and economic savings for both patients and medical institutions.
The wounds had been dressed with petroleum jelly under an occlusive dressing that consisted of gauze covered by a transparent dressing (Tegaderm; 3M, St Paul, Minn) and were left in place for 3 days. After that time, the gel foam was removed from the second-intention site and both biopsy sites were cleansed with water to remove any exudate. Then, an occlusive transparent dressing was reapplied to both sites. After this initial dressing change, dressings were changed weekly or more often at the volunteers' discretion until the biopsy sites were completely healed or reepithelialized. Efficient wound dressings can be important for both small and large wounds.
Some of the currently available surgical dressings used in dermatologic and dermatosurgical practice are discussed.
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