Hand Reconstruction After Burn Injury

Frequently burns of the hand occur as part of a major thermal injury, but appropriate treatment of the hands has high priority, because even small burns of the hand may result in severely limited function and compromised aesthetic appearance. The functional importance of the hand cannot be overemphasized, because the patient’s ability to perform useful work after recovery or the ability to care for themselves is to a great degree determined by residual hand function. This article describes the management of burn injuries involving the hand, stressing the importance of appropriate initial treatment. A comprehensive review of hand reconstruction and rehabilitation, to optimize form and function, is provided.

Key points

  • Frequently burns of the hand occur as part of a major thermal injury, but appropriate treatment of the hands has high priority, because even small burns of the hand may result in severely limited function and compromised aesthetic appearance.

  • The functional importance of the hand cannot be overemphasized, because the patient’s ability to perform useful work after recovery or the ability to care for themselves is to a great degree determined by residual hand function.

  • Reconstruction of function and aesthetics of the burned hand should have high priority in the treatment algorithm.

Introduction

Although each hand only represents less than 3% of the total body surface area, the hands are involved in more than 80% of all severe burns and are categorized as “major injuries” by the American Burn Association. Frequently burns of the hand occur as part of a major thermal injury, but appropriate treatment of the hands has high priority, because even small burns of the hand may result in severely limited function and compromised aesthetic appearance. The hand plays a crucial role in the communication with others, in sending and receiving emotional signals, and in sexuality. It is also frequently a mirror image of our mental state, which is revealed by trembling or sweating.

The functional importance of the hand cannot be overemphasized, because the patient’s ability to perform useful work after recovery or the ability to care for themselves is to a great degree determined by residual hand function. This gives it top priority in modern treatment concepts. The most important treatment principles include early initiation of physical therapy and the use of splinting, passive motion movements, and topical treatment; and, when indicated, the use of excision and grafting. A multidisciplinary team, including plastic surgeons, physical and occupational therapists, and psychologists, should be involved from the day of admission to ensure the best quality of care.

Social and professional reintegration of the patient may be delayed because of the psychological stigma that is caused by the visible mutilation. Burned hands are readily visible, whereas burned areas of the trunk or lower extremity can easily be hidden under clothing. For these reasons, burned hands deserve to be treated with most suitable best conservative and surgical techniques to achieve not only the best function but also the best possible aesthetic result. The statement of Guy Foucher that “hand surgery is also aesthetic surgery” has never been truer than in the treatment of burned hands.

Introduction

Although each hand only represents less than 3% of the total body surface area, the hands are involved in more than 80% of all severe burns and are categorized as “major injuries” by the American Burn Association. Frequently burns of the hand occur as part of a major thermal injury, but appropriate treatment of the hands has high priority, because even small burns of the hand may result in severely limited function and compromised aesthetic appearance. The hand plays a crucial role in the communication with others, in sending and receiving emotional signals, and in sexuality. It is also frequently a mirror image of our mental state, which is revealed by trembling or sweating.

The functional importance of the hand cannot be overemphasized, because the patient’s ability to perform useful work after recovery or the ability to care for themselves is to a great degree determined by residual hand function. This gives it top priority in modern treatment concepts. The most important treatment principles include early initiation of physical therapy and the use of splinting, passive motion movements, and topical treatment; and, when indicated, the use of excision and grafting. A multidisciplinary team, including plastic surgeons, physical and occupational therapists, and psychologists, should be involved from the day of admission to ensure the best quality of care.

Social and professional reintegration of the patient may be delayed because of the psychological stigma that is caused by the visible mutilation. Burned hands are readily visible, whereas burned areas of the trunk or lower extremity can easily be hidden under clothing. For these reasons, burned hands deserve to be treated with most suitable best conservative and surgical techniques to achieve not only the best function but also the best possible aesthetic result. The statement of Guy Foucher that “hand surgery is also aesthetic surgery” has never been truer than in the treatment of burned hands.

Epidemiology

Thermal injuries are the most frequently reported accidents. It is estimated that about 1% of the population in Western countries has a burn injury each year, approximately a quarter of which require medical care. The upper extremity is the most common anatomic area burned, being involved in up to 89% of burns. The two main reasons for this frequent involvement are the protective reflex with which patients try to guard their faces, and that the hand in most instances is exposed without any form of protection. The dorsum of the hand is predominantly involved in flame or explosion injuries, whereas injuries to the palm are more frequently found with chemical exposure, friction burns, or high-voltage injuries.

Anatomy

The skin and soft tissues of the hand demonstrate some anatomically unique properties. The dorsal skin is thin and flexible, supported by a thin subcutaneous layer of fatty tissue. This structure provides little mechanical protection but allows maximum tendon excursion and joint mobility without the necessity for excess skin. The skin is especially thin over the proximal interphalangeal (PIP) joints, where the extensor tendons are at risk. Attenuation or rupture of the central slip with PIP joint exposure is one of the most frequently encountered complications after deep dorsal burns. The underlying cause of many functional disturbances following burns is disruption of the coordinated interplay of extrinsic and intrinsic muscles, tendons, and joints.

The palmar skin shows similarities to the plantar skin of the weight-bearing portion of the foot. The thick subcutaneous fatty layer has a honeycomb-like structure that has shock-absorbing properties and provides grip stability by means of numerous fibrous septa that connect the skin with the deep fascia.

Treatment

Functional rehabilitation starts on the day of the injury. Customized splints made of thermoplastic material should be applied on the day of injury. Whether one chooses to initiate early motion or maintain the hand immobilized depends principally on the condition of the skin over the PIP joints. Deep burns over this area frequently lead to disruption of the central extensor mechanism over the PIP joint and development of a boutonnière deformity. However, if the skin over the PIP joint appears to be more deeply burned, it is best to maintain the joints splinted in nearly full extension. The use of Kirschner wires is frequently associated with problems (eg, pin track infections and joint stiffness) so that splinting is considered the better alternative.

Postburn deformities

A decrease in the need for late reconstructive surgical procedures is reflected in the literature over the last 35 years. Dobbs and Curreri reported a serious contracture rate of 27% in 681 adult burn patients. Pegg and coauthors reported on 411 patients with a 7.8% incidence of burn scar contractures, and Kraemer and associates noted only a 3.7% rate of reconstructive procedures 9 years after burn scar release in a population of 839 adults and children with burn injury. These data suggest that comprehensive treatment efforts, such as improved burn wound management, liberal use of positioning, improved splinting, early maintenance of range of motion, and exercise programs, have contributed to this success.

Postburn scarring and contractures affect function and the aesthetic appearance of the hand and remain the most frustrating late complication of a hand burn. If they affect the dominant hand, as they do on most occasions, the vocation and thereby the economic status of the patient may be severely impaired. A classification of postburn deformities has been proposed by Achauer :

  • A.

    Claw deformity

    • 1.

      Complete

    • 2.

      Incomplete

  • B.

    Palmar contracture

  • C.

    Web space deformity

    • 1.

      Web space contracture

    • 2.

      Adduction contracture

    • 3.

      Syndactylism

  • D.

    Hypertrophic scar and contracture bands

  • E.

    Amputation deformity

  • F.

    Nail bed deformity

  • G.

    Elbow

    • 1.

      Flexion contracture

    • 2.

      Deep burn with extensive tissue loss

    • 3.

      Heterotopic ossification

  • H.

    Axilla

Scars can also be assessed with scoring systems, such as the Vancouver Scar Scale, which allows classification of the scar based on the clinical picture.

Treatment of postburn deformities

Contractures are caused by spontaneous healing of deeper burns (ie, the burn wound itself) or more frequently by the inevitable contracture of transplanted split-thickness skin grafts. This phenomenon occurs more extensively in the acute burn situation and is less pronounced in elective situations. The clinical impression that secondary split-thickness grafts still contract more in burn wound releases than in other posttrauma situations is shared by many authors; however, scientific evidence of this tendency is rare.

Release of contractures may be accomplished by various patterns of Z-plasties, but skin grafting or flap coverage is frequently required. Full-thickness skin grafts play an important role in these secondary corrections because they are more similar to normal skin in texture, color, and resilience than split-thickness grafts and show less tendency for secondary contractures. However, full-thickness grafts take less readily than split-thickness grafts and may suffer the setback of limited availability in patients with larger burns. The latter problem, in some situations, may be solved by pre-expansion of the donor sites ( Fig. 1 ).

Fig. 1
( A,B ) Amputation deformity after third-degree burn. Syndactily DIV/V and adduction contracture of the first web space. ( C ) Contracture release with meshed split-thickness graft (DII/DIII). Full-thickness graft to DIV/DV. Reverse pedicle radial forearm flap to release the adduction contracture of the first web space. Mesh graft to pedicle. ( D ) Postoperative result after 6 weeks before removal of the K-wires.

Before surgically addressing the problem, a thorough analysis is mandatory. Several questions have to be answered:

  • 1.

    What is the nature of the contracture or the limiting scarring?

  • 2.

    Are there any underlying joint problems (eg, shrinking of the ligaments or capsules, cartilage destruction)?

  • 3.

    Are soft tissue procedures sufficient?

  • 4.

    Which type of coverage is adequate after contracture release?

  • 5.

    Where should the skin grafts or flaps be harvested?

Only after these questions have been answered can a surgical plan be designed. The most disturbing functional problems are usually addressed first; however, the patient may perceive aesthetic deformities as the more urgent problem.

Nail Bed Deformities

Dorsal scarring over the distal interphalangeal (DIP) joint leads to distortion of the eponychial fold, retraction of the eponychium, and proximal nail exposure. In cases involving only skin tightness without severe retraction of the nail fold, skin release and skin grafting may be sufficient.

When reconstruction of the nail fold is required or skin grafts are not appropriate, proximally based lateral skin flaps are recommended. The donor site of these narrow flaps can generally be closed primarily, and the resulting tip deformity evens out over time.

Claw Deformities

Claw deformities may be difficult to correct. They usually consist of hyperextended metacarpophalangeal (MP) joints with flexion contracture of the PIP joints. In contrast to Achauer’s classification, we prefer to divide claw deformities into long-standing fixed deformities with ligament shrinkage, and cutaneous deformities in which simple release of the skin contracture solves the joint position problem.

The first group requires arthrolysis, either from the dorsum or in rare cases from the palmar aspect of the joint. Both approaches to the joint can usually be performed from the dorsal skin incision. These situations generally require some sort of flap coverage because the extensive dissection has eliminated all tissue layers where skin graft take is likely. The same holds true for situations where the extensor tendon apparatus is exposed and stable soft tissue coverage is required. The choice of flaps depends on the individual profile of the patient and ranges from regional flaps, such as the dorsal metacarpal artery flaps or the radial forearm flap, to distant flaps (groin flap) and microvascular flaps.

Full-thickness skin grafts are preferred when skin grafts will suffice for skin reconstruction. Only in cases of limited availability, as when other important areas require full-thickness skin grafts (eg, eyelids, lips), are split-thickness grafts used.

Temporary fixation with Kirschner wires is indicated only in joints in which “elastic” resistance remains after release of the skin and ligaments and the patient will probably not be able to mobilize sufficient strength to overcome this resistance. The same holds true for the PIP joint in claw deformities. In most cases there remains palmar tissue deficit that requires either full-thickness skin grafting or flap coverage after release. Local intrinsic hand flaps are generally limited in these hands, although it has been shown that dorsal metacarpal artery flaps are possible even in dorsally grafted hands. Distant flaps or free tissue transfers may be indicated because the problem is usually encountered in more than one digit.

Web Space Syndactyly and Interdigital Contractures

Contracture of the second, third, and fourth web spaces usually occurs along the dorsal margin of the web. Numerous methods that generally involve local flaps and grafts have been developed to improve this surgically. They usually consist of variations of Z-plasty, such as three-, four-, or five-flap (V-M) Z-plasty, or full-thickness skin grafts. Z-plasties alone demonstrated the lowest recurrence rate of all techniques used to correct scar syndactylies. The most important step in correcting these deformities is to reconstruct the natural slope of the web space, from proximally dorsal to distally palmar. This recreates the natural appearance of the web and the natural motion pattern of the dorsal skin creases.

Contractures of the thumb

Contractures of the first web space are usually the result not only of hypertrophic scarring or skin shortage in the web but also shrinking of the adductor muscle, fascia, and possibly the basal joint capsule. First web space contractures limit movement of the thumb at the trapeziometacarpal joint, affecting grasp and pinch. Our experience has shown that in most cases at least the adductor muscle is involved, so division of the muscle is an integral part of the contracture release.

Contractures of the first web space are released with a variety of techniques, including several varieties of Z-plasties, local rotation flaps, and skin grafts. Distant or free microvascular flaps are rarely indicated. Although the technique of simple 60-degree Z-plasty gives the greatest increase in length and depth of the web space, a four-flap Z-plasty provides a smoother contour than does the standard Z-plasty.

Although the most common contracture of the thumb is an adduction deformity, other anatomic deformities are also seen. Less frequently, the thumb metacarpal may be contracted in opposition and extension as a result of bands of dorsal hypertrophic scars between the distal radius and first metacarpal, or in flexion as a result of palmar scarring producing flexion of the interphalangeal or MP joint. Correction of these contractures requires surgical release, sometimes combined with wider burn scar excision, followed by appropriate soft tissue coverage ( Fig. 2 ).

Nov 21, 2017 | Posted by in Dental Materials | Comments Off on Hand Reconstruction After Burn Injury
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