Management of Burns to the Hand

Introduction The palm of the hand comprises only one percent of the body surface area. Despite this, a burn of the hand can represent a serious short- or long-term disability. The American Burn Association, the Advanced Trauma Life Support, and the Advanced Burn Life Support curricula all recognize the severity of hand burns by classifying these as injuries requiring treatment at a burn center.[1,2] It should be noted that the term management at a burn center is not synonymous with the term admission to a burn center. Motivated and reliable patients with burns limited to the hands can be appropriately managed on an outpatient basis at a burn center, where the requisite expertise in wound care, excision and grafting, and occupational therapy are available. Initial Care The multidisciplinary treatment of burns of the hand begins on the day of injury and may be carried out simultaneously with resuscitation and other treatment if the burn involves a large body-surface area. Edema formation in burned hands hinders motion and may be a factor in later contracture formation. The hands must be elevated above the level of the heart to prevent edema formation. This is probably the most important initial step in the management of hand burns and can be done in any sized burn without hindering resuscitation, pulmonary, or other critical care management. After airway and breathing concerns are addressed, circulation needs to be assessed. Evaluation of radial, ulnar, and palmar arch pulses should be undertaken by palpation or Doppler ultrasound at the time of initial evaluation and hourly thereafter. Changes in or loss of pulse indicate the need for escharotomy if hand or arm burns are circumferential. Escharotomy may be performed at bedside using a scalpel or electrocautery under local anesthesia. In the authors’ experience, the electrocautery is more useful. Although the full-thickness burn injury is insensate, additional analgesia and sedation is usually provided with intravenous narcotic and benzodiazepine administration under electrocardiogram (ECG) and pulse oximetry monitoring. The arm should be placed in the anatomic position and a mid-radial or mid-ulnar incision made for the entire extent of the full-thickness burn. If incision on one side of the arm does not restore pulses, a second incision is made along the opposite side. Escharotomy of the fingers should be performed only after consultation with the receiving burn center. Whether or not to break blisters remains controversial. Some burn surgeons routinely debride all blisters, while others never break intact blisters. Some debride blisters only when on the hand, while others leave palmar blisters alone and debride dorsal hand blisters. The claimed advantage of leaving blisters alone is that the intact blister provides an autogenous burn dressing. The rationale for not debriding palmar blisters is that palmar skin is specialized and difficult to replace with graft. The rationale for debriding all blisters is that blister fluid contains very high levels of thromboxane B2 and prostaglandin E2.[3,4] Prospective studies demonstrating the advantage of one method over another are lacking. The authors’ practice is to debride all blisters, assuming that patient motion would likely rupture the blisters and provide a possible portal of infection. Daily Care Cleansing. Burned hands should be cleansed twice daily with a mixture of water and chlorhexidine gluconate. Burns that are clearly partial thickness may be managed with one-percent silver sulfadiazine cream. Indeterminate burns are placed in alternating agents, which include mafenide acetate 11-percent cream during the day and 1-percent silver sulfadiazine cream at night. Burns that are obviously full thickness or potentially infected are treated with twice-daily mafenide acetate. Dressings. A number of dressings are available for the treatment of clean partial-thickness burns. Porcine heterograft (pigskin) is inexpensive, but becomes inelastic once applied, hindering hand and finger motion. Allograft (human cadaver skin) provides an excellent temporary dressing but is too expensive for routine use. Biobrane® biosynthetic wound dressing (Bertek Pharmaceuticals, Morgantown, West Virginia) is a bilayer semisynthetic dressing consisting of an elastic nylon fabric bonded to a semi-permeable silastic membrane and coated with collagen polypeptides. Gloves manufactured from this material are available in a variety of sizes and are ideal dressings for clean partial-thickness burns of the hands (Figure 1). The gloves can be applied in the emergency department and then monitored daily on an outpatient basis. Nonadherence of the dressing indicates the possibility of infection or that the burn is full thickness. In the case of infection, the dressing should be removed, and topical antimicrobials placed. The gloves are flexible, facilitating hand therapy, and are less painful than daily washing and application of topical creams. The dressing material lifts off the burn wound, as epithelialization proceeds, and is trimmed with scissors. Positioning. A burned hand that is not properly positioned, splinted, or ranged will develop contractures. These represent major disabilities that are not easily corrected by later reconstructive surgery (Figures 2A and B). The typical contracture is an “intrinsic minus” position where the metacarpophalangeal (MP) joints are fixed in hyperextension and the proximal intraphalangeal (PIP) joints are fixed in a position of flexion.[3] The collateral ligaments of the MP joint are the most important structures of the burned hand. For this reason, positioning of the burned hand should place the MP joints at maximum flexion (90 degrees of flexion) to maximally stretch the collateral ligaments. The anatomic position for splinting is not the “Fosters Beer Can” grip but rather involves 30 degrees of wrist extension, MP joints at 90 degrees of flexion, and IP joints fully extended. The thumb should be fully abducted. During the resuscitation of a patient with a massive burn injury the authors prefer to use a volar cock-up splint extending from forearm to palm, elevating the wrist approximately 70 to 80 degrees for the first 24 to 48 hours. Elevation of the wrist to this degree will pull the MP and IP joints into a safe position. This splint may be secured to the forearm over the burn dressings with Velcro straps and is easily loosened to compensate for progressive edema. Occupational therapy. Occupational therapy has a major impact on hand function following thermal injury, and proper hand therapy is more important than the method (surgical or nonsurgical) utilized to address the wound itself. The occupational therapist should evaluate the patient within 24 hours of admission if not on the day of admission. Achauer points out the importance of emphasizing “elements of early care that will minimize the need for later reconstruction.”[5] Early on in the course of therapy, the authors impress upon their patients that the role of the burn team is to reestablish the normal anatomy of the hand. Reestablishment of function is the responsibility of the patient and is directly dependent upon the effort extended during occupational therapy sessions. In practical terms, the function present at one-year post-injury is likely what the patient will live with for the rest of his or her life. Splints. Hand therapy is moving away from static splinting in favor of active ranging. Static splints are now more often used for cases where the patient is unable to cooperate or participate in hand care or are used to maintain daytime gains in motion while the patient sleeps. After the edema of resuscitation resolves, a static splint should cover the volar forearm to the fingertips and should maintain the wrist in 30 to 40 degrees of elevation, the MP joints in 90 degrees of flexion, the IP joints in extension, and the thumb in abduction. Continuous passive motion machines (CPM) are a useful adjunct to hand therapy but are expensive. Finger burns may limit the ability to attach the CPM machine to fingertips. In refractory cases, the authors maintain burned hands in a functional position by temporary (two week) K-wire arthrodesis of the MP and IP joints. Surgical Management The goal of wound management is to have the skin healed by post-burn day 14.6 In many cases, this will occur nonoperatively with good wound care. In other cases, surgical excision of the burn with split-thickness skin grafting will become necessary. Grafting should be undertaken as soon as it becomes obvious that wound healing will not be complete by post-burn day 14. Considerable controversy surrounds the need, timing, and method of grafting of burned hands. Several prospective studies show that final functional outcome of burned hands is not impacted by surgical management versus nonoperative care.[3,6–9] Likewise, function is not affected by the choice of sheet graft over meshed graft, and some claim that cosmetic result is similar with meshed and unmeshed grafts to the hands. The authors’ preference is to utilize sheet (unmeshed) graft (Figures 3A and B). The recent introduction of a six-inch wide dermatome (Figure 4) allows harvest of a single split-thickness skin graft wide enough and long enough to cover the entire hand and fingers without seams. The timing of hand graft application is also controversial. For burn patients, the first goal of skin grafting is survival, the second is function, and the third is cosmesis. This should be taken into account when planning skin grafting to the burned hand. The complete coverage of two burned hands with sheet grafts will likely require harvest of four to six autografts measuring 4 x 10 inches each. These same six grafts when meshed to a 3:1 or 4:1 ratio could cover most of a chest or abdomen, reducing the total burn size. On the other hand, it makes little sense to leave a burn survivor with nonfunctional hands because grafting was deferred until the remainder of the skin was healed. A balance between survival and function must be struck. The authors’ preference is to tangentially excise burned hands under tourniquet. When a tourniquet is not used, the blood loss associated with the excision of two burned hands and all fingers can easily add up to several units. Following excision, the hands are secured to sterile hand splints in the position of function. This process is facilitated by the preoperative placement of garment hooks onto the fingernails. When fingernails are not present, a nylon suture through the fingertip provides the same function. Placement of the hand in a splint prior to graft application prevents shearing of the graft during dressing and splinting. The graft is secured with skin staples, although fibrin glue is an acceptable alternative. No outer dressings are placed, which facilitates hourly wound inspection by the nursing staff who then roll any subgraft fluid accumulation to the periphery of the graft. The splint is removed between postoperative days three to five and gentle ranging is then undertaken. Staples are removed between days four and seven. The patient is encouraged to use the hands for activities of daily living, and active range of motion exercises are prescribed. When burns of the hands are deep, debridement may result in exposure of viable tendon or joints. Flap coverage is then required. The local flap of choice is the reversed radial forearm flap. Extensive injury may require free-tissue transfer. In rare cases, local flaps are unavailable because of extent of injury and free tissue transfer is contraindicated because of overall medical condition. In such cases, a variety of distant pedicle flaps have been used. The initial flap of choice is the groin flap.[10] Special Considerations Chemical burns. Chemical burns of the hands are continuously flushed with water until the pain significantly decreases or stops. Burns caused by acids may require 20 minutes or less to achieve this goal, while burns caused by strong alkalis may require several hours of irrigation. Chemical burns caused by hydrofluoric acid are a special consideration. Hydrofluoric acid is a weak acid, and contact with solutions below 20-percent concentration usually do not cause initial skin pain.[11] Several hours later, contact with even dilute solutions will cause severe pain as the compound reaches the deeper tissues. This pain is poorly controlled with narcotics. Hydrofluoric acid avidly binds tissue and circulating calcium. Cardiac arrest from hypocalcemia has been documented with hydrofluoric acid burns as small as 2.5-percent body surface area.[11] The initial management of even small burns caused by hydrofluoric acid is ECG monitoring and replacement of intravenous calcium. Hypocalcemia is initially manifested by prolongation of the QT interval, followed by bradycardia then ventricular fibrillation. Following water irrigation, topical calcium should be applied to hydrofluoric acid burns of the hands. This is most easily done by mixing 25mL of calcium gluconate solution with 100mL of water-soluble jelly.[11] The mixture is placed into a surgical glove, which is then used to cover the burned area. Efficacy of treatment is monitored by pain relief. If topical therapy does not relieve pain, then injected calcium will be necessary. Injection of calcium gluconate solution directly into the burned area has been advocated; however, this is impractical for burns of the hand and fingers. The preferred treatment is installation of calcium through an intra-arterial catheter placed fluoroscopically to supply both the radial and ulnar circulation. A solution of 10mL of 10-percent calcium gluconate and 500 units of heparin is added to 50cc of dextrose five percent in water. This is infused over four hours.[11] Pain relief is usually dramatic and serves as indication of successful therapy. The infusion is repeated when pain returns, and multiple infusions over several days are usually necessary. Electrical burns. Electrical burns to the hand range from the trivial to the extremely complex. As electrical current passes through tissue, muscle and bone act as current resistors and generate heat, which continues to harm adjacent structures after the current is removed. The skin tends to dissipate heat externally and may remain uninjured. It is entirely possible to have dead muscle under normal or minimally injured skin in the upper extremity. Diagnosis requires a high degree of suspicion. For this reason, electrical injuries of the hand and upper extremity should be referred to a burn center. Electrical injury is one of the few occasions in burn medicine where immediate surgery may be necessary. Change or loss of pulse or neurological function may indicate the need for fasciotomy. In the upper extremity, fasciotomy should include the volar, mobile, and dorsal compartments of the forearm. It is the authors’ practice to extend a forearm fasciotomy to include median nerve decompression (carpel tunnel release) and exploration and release of the ulnar nerve at Guyon’s canal. Fasciotomy of the intrinsic muscle compartments of the hand may also be necessary. Vacuum-assisted closure devices (VAC) (V.A.C.®, KCI Corporation, San Antonio, Texas) have revolutionized wound care. A sponge designed for the hand is available and is currently in prospective clinical trials for treatment of hand burns (Figures 5a and b). It is possible that edema will be reduced by the early application of vacuum therapy to burned hands. The hand VAC sponge also provides an excellent method of splinting the burned hand in a position of function (Figure 5B).