Our hands reflexively assume a defensive posture to protect the rest our body when confronted with trauma. Consequently, hands bear the brunt of injuries in cases of burns. Severe burns involve the hand in at least 90% of the cases. The collaborative efforts of hand surgeons, burn specialists and hand therapists are imperative for the most effective treatment of burns to the hands. Assessing burn severity is not always straightforward, and several methods can be used to determine wound depth. Treatments are specifically tailored to each patient based on not only wound depth, but also the cause and anatomical structures involved. When treating burn patients, the primary objectives are to salvage as much of the hand as possible, avert the potential of contractures, and maintain functionality by implementing the best techniques with passive and active range of motion therapy.3
Pathophysiology
- Wound depth determines the degree of pathology a burn will have on the skin. Superficial burns trigger a resilient response to blister and re-epithelialize with or without local wound care. With deeper burns, encompassing the epidermis and partial- and full-thickness dermal layers, the skin loses its capacity to regenerate and is severely compromised owing to the loss of underlying vital structures. Hypertrophic scarring and contracture are the body’s debilitated response to heal and seal off the wound bed.
- Hypertrophic scarring results from the overexpression of transforming growth factor B1 (TGF-B1) and connective tissue growth factor released by fibrocytes that infiltrate deep burns.2
- Fluid contained within blisters contains proinflammatory cytokines, an excellent medium for bacterial growth, and is therefore considered counterproductive to the healing process. However, blistered skin provides an autonomous protective barrier by covering the wound until healed. Thus, removing burn blisters remains controversial.3
- The threat of contracture is limited to deep, partial- and full-thickness burns. Desiccation of underlying tendons and/or muscles or rupture of the lateral bands will result in outward contraction of the hand, functional morbidity and disability, in addition to embarrassment relating to the disfigurement.4
- Because the subcutaneous layer of tissue overlying the dorsal aspect of the hand is relatively thin compared with that of the palmar aspect, extensor tendons are more susceptible to contractures than are the flexor tendons.4
Related Anatomy
- Anatomical structures involved will vary depending on the severity of burn. The greater the wound depth, the greater risk of neurovascular, muscular, tendinous and bony structures being involved.
Incidence and Related Conditions
- Flame and scald burns account for 75% of those burn patients requiring hospitalization.4
- Flame burns occur most frequently at home (61%); 6% occur during recreational events, and 6% occur in the industrial/occupational setting.4
- 19% of burns reported involve children younger than age 5 years. Post-burn flexion contractures are most often seen in children after touching or immersing their hand in something hot, including a rotating object or machine.4
- 30% of burns involve the upper extremity.3
Differential Diagnosis
- Eczema
- Rheumatic skin disease
- Birth deformity
- Self-inflicted mutilation
Burn Severity
Symptoms vary based on burn severity, which is graded by degrees (Fufa et al., 2014).
- First-degree burns are confined to the epidermis
- Superficial
- Erythema
- Pain
- Devoid of blistering
- Second-degree burns
- Partial-thickness burns, superficial
- Blister formation followed by sloughing
- Painful, owing to survival and exposure of nerve endings
- Intact capillary wound bed with intact capillary refill (blanching).
- Injury will usually re-epithelialize completely within 10-14 days with local wound care; hair, sebaceous glands, and sweat glands will be restored.3,5
- Partial-thickness burns, deep
- Pain is absent because the wound depth extends beneath nerve endings
- Few epithelial cells remain and take longer than 2–3 weeks to heal
- Increased chance of hypertrophic scarring owing to collagen deposition.3,5,6
- Topical antimicrobial dressing affords the ability to determine wound depth and time needed to heal.5
- May require skin grafting.5
- Third-degree burns
- Full-thickness burns involve epidermis and dermis
- Pallor is due to secondary thrombosis
- Leathery, firm, desiccated or carbonized skin on exam3,5
- Insensate owing to destruction of cutaneous nerve endings
- Full-thickness burns will not re-epithelize
- Fourth-degree burns
- Full-thickness burn
- Most severe, encompassing destruction of fat, tendon, muscle, vasculature, nerves, bone, and joints 3,4
- Heals by scar tissue formation4,6
- Compartment syndrome may occur concomitantly with fluid resuscitation in cases of deep-partial or full-thickness burns 3
- Levels of contractures also are graded (Types I–III) based on degrees of extension and flexion, with the most severe form of contracture being the claw-hand deformity 4
- Web contractures are not uncommon in severe cases involving dorsal-, palmar- , or inter-digital web spaces 4