Wound Classification....

Wounds encountered in surgical and dermatosurgical practice can be classified according to their thickness, the involvement of skin or other structures, the time elapsing from the trauma (breaking of skin continuity), and their morphology. Additional classifications include factors that determine how to close the wound, classification of how the wound heals, and classification of the wound by bacterial contamination.

Thickness of the wound

• Superficial wounds, involving only the epidermis and the dermis up to the dermal papillae
• Partial-thickness wounds, involving skin loss up to the lower dermis (Part of the skin remains, and shafts of hair follicles and sweat glands are leftover.)
• Full-thickness wounds, involving the skin and the subcutaneous tissue (Tissue loss occurs, and the skin edges are spaced out.)
• Deep wounds, including complicated wounds (eg, with laceration of blood vessels and nerves), wounds penetrating into natural cavities, and wounds penetrating into an organ or tissue
• The image below depicts first-degree, second-degree, and third-degree burn thickness.Burn degree diagram. Image courtesy of Wikimedia Commons.

Involvement of other structures

• Simple wounds, comprising only 1 organ or tissue
• Combined wounds (eg, in mixed tissue trauma)

Time elapsing from the trauma

• Fresh wounds, up to 8 hours from the trauma
• Old wounds, after 8 hours from trauma or skin discontinuity

Morphology

• Excoriation or scarification, the most superficial type
• Incised wound, mainly as a result of surgical intervention
• Crush wound, made with a heavy blow of a cutting tool (eg, hatchet, sword, sable)
• Contused wound, the most common type of wound encountered in traffic accidents
• Lacerated wound, when fragments of tissue are torn away with a sharp-edged object
• Slicing wound (A classic example is detachment of epicranial epineurosis.)
• Stab wound, made with a pointed tool or a weapon
• Bullet wound
• Bite wound
• Poisoned wound

Factors that determine how to close the wound

• Type of wound
• Size of wound
• Location of wound (Poor vascular areas or areas under tension heal slower than areas that are highly vascular.)
• Age of wound (fresh surgical wounds vs chronic wounds)
• Presence of wound contamination or infection (Bacterial contamination slows down the healing process.)
• Age of the patient (The older the patient, the slower the wound heals.)
• General condition of the patient (Malnutrition slows down the healing process.)
• Medication (Anti-inflammatory drugs may slow down the healing process if they are taken after the first several days of healing. After this period, anti-inflammatory drugs should not have an effect on the healing process.)

Classification of how the wound heals

• Healing by first (primary) intention (primary healing): The wound is surgically closed by reconstruction of the skin continuity by simple suturing, by movement (relocation) of skin fragments from the surrounding area (flaps), or by transplantation of free skin elements (grafts) of different thickness (eg, split- or full-thickness grafts). Primary healing is usually the case in all wounds in which the anatomical location and the size allow the skin continuity to be restored.
• Healing by second intention (secondary wound healing): After wound debridement and preparation, the wound is left open to achieve sufficient granulation for spontaneous closure (reepithelialization from remaining dermal elements [eg, hair follicle] or from wound borders). Secondary healing is how abrasions or split-thickness graft donor sites heal.
• Healing by third intention (tertiary wound healing [delayed primary closure]): After wound debridement and preparation (ie, treatment of local infection), the wound is left open and then closed by primary intention or finally by surgical means of skin grafting. Tertiary healing is how primary contaminated wounds or mixed tissue trauma wounds (eg, after reconstruction of hard tissue) heal.

Classification of wound by bacterial contamination

The 4 types of surgical wounds are as follows: clean, clean contaminated, contaminated, and dirty.

• Clean wounds are usually wounds made by the doctor during an operation or under sterile conditions. Only normally present skin bacteria are detectable.
• In clean-contaminated wounds, the contamination of clean wounds is endogenous and comes from the environment, the surgical team, or the patient's skin surrounding the wound.
• In contaminated wounds, large contaminates infect the wound.
• In dirty wounds, the contamination comes from the established infection.

In the daily praxis, the main objective for dermatologists, dermatosurgeons, and surgeons is to transfer the wound from a spontaneous stage to a surgical stage and to heal the wound by primary intention. However, this is not always possible or practicable. In such cases, wounds heal mostly by secondary intention, and the injured tissue becomes healthy again; appropriate wound dressings are necessary to give the wound an optimal environment to heal.