A. Types of Wounds

1. Majority of the >1.2 million wounds treated annually are due to accidents or fights
   1. Sharp trauma - about 50% of cases
   2. Blunt trauma
2. Minority are due to animal (or human) bites
3. Most persons with wounds are young men
4. Careful attention to host medical history important in evaluating wound
   1. An apparently "mild" wound can become life-threatening in certain patients
   2. Patient's history of scarring will also help with prognosis and guide treatment
5. Host Factors Increasing Risk of Poor Outcome
   1. Extreme older and younger age
   2. Diabetes Mellitus
   3. Chronic Renal Failure
   4. Obesity
   5. Malnutrition - protein and/or vitamin C deficiencies
   6. Immunosuppressive Medications, particularly glucocorticoids
   7. True Connective Tissues Diseases: Ehler-Danlos, Marfan's, Osteogenesis Imperfecta
6. Risk factors for poor outcomes related to impaired wound healing (see below) [2]

B. Evaluation

1. History - thorough whenever possible
   1. Specific questions about incident(s) surrounding wounds
   2. Particular attention to host factors that adversely affect healing (see above)
   3. Ask about allergies to local anesthetics, latex, or antibiotics
   4. Ask about previous tetanus vaccination (and give booster if <5-10 years previously)
2. Physical
   1. Attention to other scars (keloids), if present
   2. Keloids extend beyond boundaraies of original injury
   3. Hypertrophic scars remain within the boundaries of the original injury
   4. Range of motion of structures close to wound should be assessed
   5. Examination of surrounding nerve and vascular structures is critical
3. Examination of Wound
   1. Sterile technique, proper lighting, control of bleeding is required
   2. Anesthetizing the wound area is highly recommended in most cases
   3. Care must be taken to fully evaluate the extent of the wound
   4. Special attention to involvement of nerves, blood vessels, tendons, ligaments

C. Wound Preparation

1. This outline will cover general principles, not techniques
2. Use of anesthetic agent is generally recommended
   1. Permits detailed examination of the wound
   2. Allows expedient debriding and improved visualization
3. Anesthesia
   1. Usually administred by local infiltration of agent(s)
   2. Amides or esters, with or without epinephrine, are typically used
   3. Pain associated with local anesthesia is common and can be avoided (see below)
   4. Regional nerve blocks may be used for large wounds
4. Common Local Anesthetic Agents
   1. Generally require ~2 minutes for onset of action
   2. May be used with or without epinephrine (which lengthens duratin of action)
   3. Three most common agents are listed with their maximal safe doses (max)
   4. Procaine (Novocaine®) - ester, 0.5% solution; 0.25-1.5 hours duration, 7-9 mg/kg max
   5. Lidocaine (Xylocaine®) - amide, 0.5-2% solution, 1-4 hours duration, 4-7 mg/kg max
   6. Bupivacaine (Marcaine®) - amide, 0.125-0.25% sol, 4-16 hours duration, 2-3mg/kg max
5. Minimizing Pain During Wound Treatment
   1. Initially apply topical anesthetics (caution on absorption of drugs)
   2. Add 1cc 10% sodium bicarbonate per 50cc anesthetic agent
   3. warm solution of anesthetic
   4. Inject agents through edge of wound (only for clean wounds)
   5. Use small needle and slow infiltration rates
6. Steps in Preparation of Wound
   1. Sterilize local area and administer anesthesia
   2. Hair removal - avoid shaving which may permit bacterial entry; clipping preferred
   3. Irrigation - high pressure with 35-65 cc wyringe and 16-19 gauge needle
   4. Avoid splatter from irrigation, which may contain transmissible (infectious) agents
   5. Saline is probably the best agent for irrigation
   6. Avoid hydrogen peroxide, detergents, and iodine solutions which can damage tissues
   7. Debride (remove) all necrotic tissue including fat, muscle, sckin
   8. Liberal use of surgical debridement techniques is generally recommended
7. Wound Closure
   1. Primary closure (immediately after debridement) is usually preferred over delay
   2. Primary closure will speed healing and reduce patient discomfort
   3. Closure can be delayed for 6-24 hours (depending on wound character) without major increased risk of infection
   4. Early closure preferred for immunocompromise, contamination, poor vascular supply
   5. Sutures are most commonly used to close wounds
   6. Staples, clips, adhesives and surgical tapes are also used, depending on situation
   7. Sutures are resorbable (usually for deep structures) or non-resorbable (usually for skin)
   8. Tissue adhesives (usually octylcyanoacrylates) are under FDA review
   9. Optimal cosmetic results are usually a major goal and require special attention
8. Stimulation of Healing (see below) [2]
   1. Great deal of interest in stimulating skin growth at wound edges using therapeutics
   2. Overall disappointing results in human studies with biological growth factors
   3. However, some agents, though not optimal, have been approved
   4. These include PGDF (approved in USA) and FGF (approved in Japan)
   5. Continued interest in growth factors, artificial skin substances, ex vivo skin growth
9. Skin Substitutes [2,3]
   1. Immediate coverage of wound (especially burn) is critical
   2. Epidermal, dermal and composite skin substitutes are available
   3. Autologous and allogeneic cultured epidermal cells can be used
   4. Allogeneic cultured cells readily available but only temporary
   5. Autologous cultures require 2-3 weeks and is very costly, but is permanent
   6. Dermal skin substitutes are readily available
   7. Alloderm® is decellularized allogeneic human skin
   8. Integra® is bovine collagen with chondroitin 6-sulfate
   9. Dermagraft-TC are fibroblasts on nylon mesh
   10. Apligraf® is a composite with bovine collagen, allogeneic fibroblasts, epidermal cells
   11. Composite cultured skin is collagen matrix with fibroblasts and epithelial cells

D. Post-Operative Care

1. Wounds should be kept clean
2. Usually cover with a nonadherent dressing for 24-48 hours (allows epithelialization)
3. Maintain moist environment around the wound stimulates epithelialization
4. Keep injured area elevated to reduce edema (and consequent stress on wound closure)
5. Routine use of prophylactic antibiotics is not recommended
   1. Decision is based on degree of wound contamination and likely organisms
   2. Host factors such as immunocompromise, heart murmers, vascular disease important
6. Antibiotics are recommended for the following:
   1. Open fractures and exposed joints
   2. Human, dog and cat bites
   3. Intraoral lacerations
7. Suture or Staple Removal
   1. Seven days for most areas of the body
   2. Three to five days for facial sutures
   3. Up to 2 weeks for areas under tension such as joints
   4. After removal, reinforce wounds with surgical adhesives or tapes to prevent dehiscense
8. Scars will change over following 12 months, so revisions should allow for this
9. Avoid sun exposure over scars, as this will often lead to hyperpigmentation

E. Wound Healing [2]

1. Critical for responses to:
   1. Traumatic wounds
   2. Burns
   3. Skin Ulcers: pressure, venous stasis, diabetes mellitus
   4. Impairment of wound healing leads to chronic skin ulceration
   5. Skin ulcers lack barrier function of skin and complications are very common
2. Stages of Wound Healing
   1. Clotting and Inflammation
   2. Epithelialization
   3. Granulation
   4. Neovascularization
   5. Process described in detail in Dermatology Section
3. Key Cell Types and Functions
   1. Clotting Cascade - platelets not essential but augment process
   2. Inflammatory Cells - especially the monocyte / macrophage lineage
   3. Epithelial Cells
   4. Fibroblasts
   5. Healthy blood supply to the wound area
4. Abnormal (Slow) Wound Healing
   1. Primarily in conditions of impaired vascular supply
   2. Diabetes mellitus
   3. Venous stasis conditions (heart failure, venous insufficiency)
   4. Pressure Ulcers due to incapacitation
   5. Atherosclerotic disease
   6. Note that fetal wound healing is very rapid with essentially no scarring
5. Synthetic or cultured skin may be useful in patients with impaired wound healing (above)

References

1. Singer AJ, Hollander JE, Quinn JV. 1997. NEJM. 337(16):1142
2. Singer AJ and Clark RAF. 1999. NEJM. 341(10):738
3. Bello YM and Phillips TJ. 283(6):716