Hand burns

Introduction

Loss of hand function is the leading cause of impairment following burn injury [18]. Over 80% of severe burns involve the hands [2]. In addition, superficial and partial-thickness burns are often incurred during routine occupational and recreational activities due to the hand’s function as the primary point of physical contact during day-to-day activities. Even small hand burns could potentially impair function and quality-of-life.

Advances in acute burn care have made survival of previously fatal injuries possible and shifted the focus of burn care and research towards optimizing functional outcomes. Consequently, care for and restoration of hand function have received increased attention with a multidisciplinary team of burn surgeons, plastic surgeons, rehabilitation physicians, and physical and occupational therapists coordinating care at specialized burn centers to improve outcomes.

Initial evaluation and history

Following trauma protocols, all patients presenting with burn injuries should undergo an initial evaluation focusing on systemic illness and life threatening injuries. Once this has been completed, the burn injury itself may be addressed. In evaluating hand

Marc G. Jeschke et al. (eds.), Handbook of Burns

burns, a careful history, including handedness, mechanism, and the circumstances surrounding the injury should be obtained. The date of the patient’s last tetanus vaccination or booster should be documented and tetanus toxoid or immunoglobulin should be administered as necessary.

After a thorough history, the physical examination proceeds by classifying the extent and depth of burns. Other injuries, such as crush or laceration, occurring in conjunction with the burn should also be documented. The extent of the burn may be efficiently recorded using a hand diagram as well as distinctive markings to indicate the depth of the burn in each area and damaged or exposed underlying structures. The appearance of the hand should also be noted. Edema, especially on the dorsum of the hand and around the joints, may lead to a posture with decreased tension on the collateral ligaments (i. e. extension through the metacarpophalangeal joints and flexion through the interphalangeal joints). Corrective splinting and early motion may be required to minimize the risk of fixed contracture.

Particular attention should be paid to vascular perfusion, especially in the presence of circumferential burns. Decreased perfusion may be suspected if capillary refill is greater than 2–3 seconds or absent, radial or ulnar pulses are diminished, or the skin is cool to the touch. Areas of suspected vascular injury should be further evaluated with a Doppler ultrasound examination. Patients with circumferential

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forearm burns are at risk for vascular insufficiency or compartment syndrome when edema collects deep to an unyielding eschar resulting in decreased arterial flow and venous congestion. To prevent compartment syndrome, escharotomy or fasciotomy (as described below) should be performed to restore adequate perfusion.

Initial wound management

During the initial evaluation of burn wounds, foreign material should be removed and thin or loose blisters should be debrided. An appropriate dressing is then applied. The choice of dressing is dependent on the depth of the burn with the goals of preventing infection, promoting re-epithelialization, avoiding water and heat loss, and keeping the wound moist. Additionally, the ideal dressing should be easy to apply and reduce pain.

Local wound care is the definitive treatment for superficial and superficial partial-thickness hand burns with the objective of optimizing re-epithelia- lization. We prefer an ointment with antimicrobial properties such as bacitracin and a non-adherent gauze dressing. For deeper burns that may form an eschar, we prefer silver sulfadiazine (Silvadene), which provides increased antibacterial protection and is soothing when applied. Silvadene forms a film or “pseudo-eschar” after application necessitating daily cleansing prior to repeat use. Sulfamylon (Mafenide) is preferred for infected burns due to sulfadiazine’s poor eschar penetration. However, metabolic acidosis resulting from carbonic anhydrase inhibition is a potential side effect for which the treating physician must be vigilant. When epithelialization is imminent or occurring, the dressing may be switched to bacitracin and a non-adherent gauze. There is no evidence supporting the use prophylactic antibiotics.

tissue edema under the tight shell-like eschar. Decreased pulses or Doppler signals, cool extremities, or decreased capillary refill in this setting should be addressed immediately with escharotomy to increase distal perfusion [3]. Escharotomy may be performed under general anesthesia in the operating room or at the bedside in the intensive care unit with appropriate analgesia and sedation. Eschar is insensate and pain should be minimal during the procedure. A full release of the forearm may be achieved using either electrocautery or a scalpel to incise the eschar through two longitudinal incisions, radially and ulnarly, to the level of the 1st and 5th metacarpophalangeal joints. Furtherer decompression of the hand itself is achieved through longitudinal incisions between the metacarpals from the base of the hand to the head of the metacarpal taking care not to expose any tendons (Fig. 1). Digital escharotomy is avoided at our institution; however, one small case series suggests that it may decrease finger necrosis [24]. It is crucial that digital incisions be limited to the eschar itself as deeper incisions may expose underlying vital structures unnecessarily.

Compartment syndrome should be suspected in all patients but is less likely in patients with isolated thermal burns limited to superficial tissues. Electri-

Escharotomy and fasciotomy

Deep extremity burns, particularly those that are circumferential, must be closely monitored for distal vascular insufficiency. Additionally, patients who sustain extensive burn injuries require large volumes of intravenous fluid and will develop significant soft

Fig. 1. Escharotomy of the hand is performed by incising the eschar in the intermetacarpal spaces. Care is taken not to unnecessarily expose underlying structures

cal burns and burns with an associated crush injury are more likely to result increased compartmental pressures and a resulting compartment syndrome. Deep muscle compartments are often more affected than superficial after electrical burns because bone has a very high resistance to the flow of electrical current. Neuropraxia following electrical shock can also complicate the initial assessment.

The diagnosis of compartment syndrome is generally clinical and heralded by the constellation of pain on passive stretch, paresthesias, pallor, paralysis, decreased pulses, and poikilothermia (the 6 P’s). Systemic deterioration, including myoglobin induced metabolic acidosis, may be the only sign of compartment syndrome in an obtunded patient with myonecrosis. Although not specific to burns or electrical injuries, compartmental pressures of > 30 mmHg or within 10–20 mmHg or diastolic pressure are also diagnostic criteria of compartment syndrome. In the setting of suspected compartment syndrome, or failure of escharotomy to restore distal perfusion, dorsal and volar fascial incisions, including carpal tunnel release, should be made and the muscle compartments examined and debrided as necessary [3–5].

healthy, bleeding tissue. For excision of web spaces and other areas in which the Goulian knife is difficult to maneuver, the Versajet (Smith and Nephew, London, UK) high-pressure water jet system is useful [15, 23] (Fig. 2). Excision on the dorsum of the hand should be performed carefully given the paucity of

Surgical management: Early excision and grafting

Early excision and grafting has been shown to reduce hypertrophic scarring and subsequent contractures leading to a reduced need for later reconstructions. Superficial and intermediate partial-thickness burns will often heal within 2 weeks and rarely require excision. However, deeper wounds that are expected to take longer to heal (i. e. longer than 21 days) should be carefully monitored for healing potential. Once clear that wounds will not heal in a timely fashion, plans for excision and grafting should be made. Given the relatively small surface area of the hand, timing of hand excision in a patient with extensive burns should be weighed against the need to remove large areas of eschar to prevent burn wound sepsis [10].

Excision and grafting is usually performed under general anesthesia with the use of a tourniquet to reduce blood loss. Excision is performed with the use of a Goulian knife to remove eschar to a depth of

Fig. 2. The Versajet water dissector provides precise tissue excision and is particularly suited for use in areas of convexity or concavity

subcutaneous tissue and subsequent risk of exposing tendons. Small areas of exposed tendon may be covered with surrounding soft tissue to avoid the need for flap coverage. However, larger areas of exposed tendons and joints will not be amenable to grafting without the use of flap coverage [13]. Once excision is complete, the tourniquet should be deflated to assess tissue viability by observing bleeding. Epinephrine (concentration 1 : 10,000) soaked Telfa (Mansfield, MA) and laparotomy pads should be applied for ten minutes. The wound bed is then assessed for hemostasis and new Epinephrine soaked dressings replaced as needed to achieve a bloodless field. Electrocautery should be used sparingly and only on small focal areas of bleeding.

The majority of hand burns can be covered with split thickness skin grafts. In order to guide graft harvest, the wound bed should be templated and the template transposed to the planned donor site. The anterolateral thigh is the preferred donor location in adults and older children. The buttocks, taking care to remain beneath the diaper area, are harvested in younger children. A dermatome with the widest guard appropriate for the amount of skin needed helps to minimize the number of graft junctions. For the majority of the hand, 0.012 inch thick grafts are sufficient while 0.015–0.018 inch thick grafts are necessary for the palm [19]. Sheet grafts are preferred to meshed grafts to improve functional and cosmetic result. Full-thickness grafts harvested from the inguinal crease or the flank may be the most appropriate choice for small burns on both the dorsum of the hand and the palm [7, 25]. Grafts are affixed with absorbable sutures around the edges and fibrin glue applied to the wound bed. The edges of the graft are reinforced with Hypafix (Smith and Nephew, London, UK) and Mastisol (Ferndale Laboratories, Ferndale, MI). A dressing of non-adherent material, fine-mesh gauze, kerlex rolls, and a custom fabricated splint is applied. Of note, grafting should take place in the same position as splinting, attempting to maintain tension on the collateral ligaments and abduct the first webspace. The dressing is removed on post-operative day one and fluid collections are evacuated with a small incision in the graft. It is important to note that we do not make any pie-crusting incisions in the graft at the time of initial placement. The wound should be inspected daily until no fluid

collections are noted. The dressing is maintained until post-operative day five and then replaced with a lighter non-adherent dressing to allow for range of motion exercises [27]. The donor site, if properly harvested and dressed, should re-epithelialize spontaneously within two weeks. We prefer Mepilex AG (Molynycke Health Care, Norcross, GA), a silver-im- pregnated dressing, although a non-adherent gauze and bacitracin is also acceptable.

Two exceptions to early excision are palm burns, particularly in pediatric patients, and small burns. Palm burns are common in the pediatric population after contact with a stove or fireplace. These burns are usually deep partial-thickness or more superficial and heal well with conservative management. Avoiding excision will help to protect palmar sensation that is vital to overall hand function. It is critical that children with palm burns undergo aggressive range of motion therapy as these burns are prone to contracture particularly if a more conservative approach to excision is taken [9]. Parents must be instructed on how to adequately range the hand and the child should do so at least 10 times daily. Splints should only be used if early signs of contracture are noted. Small burns (either linear burns or less than the size of a small coin) should also be given a chance to heal without excision.

Tissue flaps

Severe burns, especially on the dorsum of the hand where the skin is thin with little underlying subcutaneous tissue, are often not amenable to skin grafting due to exposed bone or tendon. When this situation arises, flap coverage is required. Additionally, digits sometimes require vascular soft tissue coverage to optimize function. Numerous soft tissue flaps have been described to provide durable coverage for areas for which skin grafting would not be appropriate. It is important to keep in mind associated injuries that should be treated at the time of grafting. For example, damage to extensor tendons or intra-articular burns may result in eventual joint contracture. In these cases, arthrodesis in the optimal position may facilitate a swifter functional recover.

Local flaps. The radial forearm fasciocutaneous or fascial flap, based on the radial artery, is an appro-