A wound is damaged or disruption to the skin and, before treatment, the exact cause, location, and type of wound must be assessed to provide appropriate treatment.[1][2][3] Each clinician will have widely differing and distinct opinions and understanding of wound care depending on their prior experience. The reason for this because of the widely differing and distinct types of wounds, each with their etiology. An ostomy nurse will have a completely different approach to wound care that will require an orthopedic surgeon who deals with trauma and both will be far different from a dermatologist who treats burn victims. Nevertheless, each of these healthcare providers is performing wound care. How do professionals then approach wound assessment when the causes are so diverse? Below are some basic questions to ask during a wound assessment to best classify and treat a wound presenting in a clinical setting.

Clinicians perform wound assessment as a means for determining the appropriate treatment for an extremely diverse grouping of disease processes. Just as hypertension is not treated the same as diabetes, each of the underlying etiologies of the given wound must be identified and treated as if it were its own disease, not a blanket classification of "wound."[4][5]

The initial assessment should begin with the following:

• How: How was the wound created and, if chronic, why is it still open? (underlying etiology)
• Where: Where on the body is it located? Is it in an area which is difficult to offload, or to keep clean? Is it in an area of high skin tension? Is it near any vital structures such as a major artery?
• When: How long has this wound been present? (eg., chronic or acute)
• What: What anatomy does it extend? (e.g., epidermis, dermis, subcutaneous tissue, fascia, muscle, tendon, bone, arteries, nerves)
• What: What comorbidities or social factors does the patient have which might affect which might affect their ability to heal the wound?
• Is it life threatening?

All of these factors significantly affect the treatment plan moving forward. While there are many excellent biologics, skin grafts, and other options available, without the appropriate understanding of the nature of the wound the chances of healing decline significantly.

While some wounds are simple, the majority of wounds many clinicians encounter are caused by or complicated by some other issue.[6][7][8][9] These are a few of the possible complications from different wound types:

• A chronic wound will have a different makeup than that of an acute wound, requiring conversion for healing.
• An underlying infection will prevent wound healing even if the infection is subacute.
• A damaged or constricted arterial supply will prevent appropriate blood flow to the wound.
• A damaged venous supply will cause venous stasis.
• Physical pressure on chronic ulceration will cause repeated damage, preventing healing.

 Each of the potential underlying causes must be addressed for the wound to heal. Before determining the underlying cause, it is important to determine what type of wound the patient has. These subclassifications can be acute or chronic.[3][4][10]

Types of Wounds

Acute

Clinicians assess acute wounds by the method of injury and damage to the soft tissues and bony structures. In crush or high impact injuries, there is an area of demarcation which is not fully recognized until sometimes as much as a week or 2 later. For this reason, it is important to determine the method of injury and to keep in mind that the wound seen is not necessarily the entirety of the wound which will be present in a week. In these cases, the patient and their family should be educated on this progression to prevent frustration and misunderstanding.

For all acute types of wounds, it is important to determine the length of time since injury (days or hours), the involvement of neurovascular supply, muscle, tendon, ligament, and bony involvement, and the likelihood of contaminants in the wound. Also of importance is when the patient had their last tetanus shot. CLinicians should start antibiotics if the wound is severely contaminated or if it is longer than 3 hours since the injury. All underlying tissue should be repaired if possible, and the wound should be irrigated to remove contaminants and bacteria.

In cases of open fracture the most used classification is Gustillo-Anderson:

• Type 1: Clean wound, less than one cm with minimal soft tissue damage, adequate soft tissue coverage of bone, and no periosteal stripping
• Type 2: Wound with moderate contamination, greater than one cm with moderate soft tissue damage, adequate soft tissue coverage of bone, and no periosteal stripping
• Type 3A: Wound with significant contamination, with significant soft tissue damage, adequate soft tissue coverage of bone, and periosteal stripping is present
• Type 3B: Wound with significant contamination, with significant soft tissue damage, unable to cover bone with soft tissue (requiring graft), and periosteal stripping
• Type 3C: Similar to type A or B, however with Arterial damage requiring repair

Chronic

If a wound becomes arrested in progression through the normal stages of inflammation and wound healing and remains open, then this becomes a chronic wound. While there is no consensus as to when a wound becomes chronic, a study by Sheehan et. al determined that in diabetic wounds, the degree of healing at 4 weeks is a strong predictor of 12 week healing, suggesting that those wounds which have not healed approximately 50% in 4 weeks are likely to have an arrested healing process, and therefore are chronic.[11][12]

In the chronic setting, the main goal is to identify why the wound is not healing and to fix this obstacle or obstacles.

There are a limited number of reasons a wound becomes chronic; however, once these reasons are rectified, the wound resumes its natural course of healing.

1. Arterial: Is there enough blood flow? Generally speaking, an ABI of less than 50 mm Hg, or an absolute toe pressure less than 30 mm Hg (or less than 50 mm Hg for persons with diabetes) indicates critical limb ischemia and predicts failure of wounds to heal.
2. Venous: Pressure-induced changes in blood vessel wall permeability then lead to leakage of fibrin and other plasma components into the perivascular space. Accumulation of fibrin has direct and negative effects on wound healing as it down-regulates collagen synthesis.
3. Infection: Underlying infectious processes including cellulitic and osteomyelitis processes will inhibit wound healing. Culturing for aerobic, anaerobic, and fungal pathogens is recommended.
4. Pressure: Increased pressure to the area of concern will destroy new tissue growth and prevent proper perfusion of blood to the wound site. These areas need to be offloaded to avoid pressure in the area.
5. Oncologic: Always biopsy areas of concern in nonhealing wounds, as this can be an atypical presentation of some types of malignancies.
6. Systemic: There are multiple systemic diseases which inhibit wound healing, with diabetes being the most common culprit. It has been determined that uncontrolled blood glucose levels suppresses the body’s normal inflammatory response, as well as causing microvascular disease which limits healing.
7. Nutrition: While serum albumin has not been found to be a good predictor of wound healing, there is some evidence that protein malnutrition, as well as insufficient levels of certain vitamins and minerals, will limit the body’s ability to heal chronic wounds.  
8. Pharmacological: Hydroxyurea has been reported in multiple instances to cause nonhealing ulcerations.
9. Self-inflicted/psychosocial: There are instances where a patient is causing the ulceration, either on purpose or as a result of noncompliance. This is often the hardest factor to spot and overcome, but must always be a consideration.

Once the underlying issues are determined, then the assessment of the actual wound is performed.

What type of tissue is present in the wound? Is it healthy normal tissue? Is it granular, necrotic, fibrotic? In red, granular tissue the treatment is generally to keep it clean and moist and to offload to allow healing to take place. If the wet necrotic tissue is present, this should be resected immediately to remove a potential nidus for infection, if dry and there is a compromised vascular supply the patient may need revascularization before debridement, or the debridement will just cause an increase in the wound size. For fibrotic tissue, debridement must be performed to create a healing wound environment. This can be performed with scalpel or curette, or with enzymatic debridement.

Is the wound wet or dry? A simple rule of thumb is that if it is wet, dry it, if it is dry, wet it. The idea with this is to keep the wound at an optimal moisture level for healing. Hydrogels are useful for keeping a relatively dry wound moist, while moisture absorbing materials such as alginates are useful for drying out the weeping ulcer. Some wounds, such as venous stasis ulcerations, are so wet that they require daily dressing changes just to keep the surrounding skin from becoming overly wet.

Is the surrounding tissue healthy, friable, or macerated? Friable skin (fragile and thin) especially is a challenge as any adhesive may tear the skin, increasing the size of the wound. Macerated skin is found when the moisture from the wound is not well controlled. The excess moisture softens the skin till it begins to break down, therefore increasing the wound size.

Finally, is the wound infected? Cellulitic appearing skin appears more erythematous and edematous than the surrounding tissue, with an increase in temperature to the area in question. There is often purulent discharge and, depending on the offending organism, may have a strong odor. The presence of a strong odor, especially in venous stasis wounds, is not indicative of infection unless it is either noticeably worsened from normal, or combined with other signs of infection; as heavy drainage will have a distinct odor by itself. In the case of lower extremity erythema and edema, especially where it is seen bilaterally, this may simply be vasculitis and not an infection. A simple test is to elevate the leg for three to five minutes. If the erythema resolves significantly during that period, it is likely that it is vasculitis, not an infection. However, if there is an open wound and/or other reasons to be suspicious for infection, always err on the side of caution.

Imaging in these cases is vital, as the depth and extent of the infection will change the type of treatment. On plain film x-ray, it is possible to see the destruction of bone, which indicative of osteomyelitis (bone infection). Generally speaking, bone with visible destruction from infection needs to be resected and treated with 6 weeks antibiotics to clear the infection fully. Other signs to look for are focal areas of decreased density which can indicate an abscess formation which will need to be incised and drained, or soft tissue erythema which is diffuse areas of decreased density which indicates gas in the tissue and is seen in severe infections including clostridium perfringens, which is often seen in gas gangrene and is a medical emergency which requires immediate excision and irrigation of infected tissues.

If the infection is suspected be sure to take deep cultures of the wound (just swabbing the rim will likely culture a wide variety of organisms.) If the purulent discharge is present, this is a good source for culture. If sepsis or bacteremia is suspected and the patient is to be given antibiotic therapy, make sure to take the blood cultures before antibiotic therapy is given.

For local treatment of infected wounds, irrigation and debridement are warranted, and if there is a concern for abscess, incision and drainage are necessary to remove any nidus of infection.

While there are many factors to consider when approaching a wound, understanding the nature of the wound and underlying factors causing the wound in question will lead to successful evaluation and treatment of the wound.

This review is not exhaustive, but it provides a basic understanding of the common types of wounds, as well as the underlying concerns for each. The takeaway is the need for appropriate assessment of wounds. Too often, wounds are not treated properly because of a lack of understanding of the underlying disease process.