Extremity burn reconstruction

Edema

Edema occurs in all burn injuries but has to be kept to a minimum in hand burns for two reasons. Firstly, edema causes the joints to be in an unfavorable position and become stiff leading to contractures. Secondly, edema fluid is rich in protein and as it settles it causes fibrosis hampering the gliding motion of the tendons. Edema can be considered as “tissue glue”. Edema control is started on admission by splinting and elevating the hand above the level of the heart. Without splinting, the wrist goes into flexion, and this makes the metacarpophalangeal joints (MCPJ) go into extension. Hyperextension at the MCP joint leads to increased tension on the flexors causing flexion of the interphalangeal (IP) joints. If the hand remains in this position it leads to claw deformity.

Apart from the flexed wrist position, edema of the hand by itself can lead to claw deformity. The skin on the palm is tightly tethered to the deeper structures by fibrous septae, while the dorsal skin is loosely attached to the deeper structures. So the edema fluid accumulates on the dorsum drawing the MCP joints into hyperextension and the IP joints into flexion. Even mild edema on the dorsum of the hand can cause hyperextension of the MCP joints.

The burnt hand is splinted with the wrist at about 20° of extension, MCP joints at about 80° of flexion, and the IP joints at as much extension as possible. When the MCP joint is hyperextended there is minimal contact between the articular surfaces and more space for fluid to accumulate in the joint leading to fibrosis and joint stiffness. When the MCP joints are flexed, the contact area between the articular surfaces increases with minimal space for fluid accumulation. In the interphalangeal joints, articular congruity is present in both extension and flexion. The IP joints need to be placed in extension to prevent the contracture of the volar capsule. In addition, if the dorsal skin is involved in burns, IP joint flexion causes tension on the extensors leading to volar subluxation of the lateral bands, and attenuation of the extensor central slip mechanism leading to boutonnière deformity. Thinning and loss of skin due to pressure can lead to non-reconstructable deformity, so every effort must be taken to reduce edema formation in the hand.

Infection

Infection can convert a superficial burn to deep burns and if extensive can be a cause of sepsis leading to death. Early excision and skin grafting to achieve wound closure have been shown to reduce infection-related complications, reduce the length of hospital stay, and improve survival in burned patients in all ages.

Tangential excision

Tangential excision, used in deep dermal burns, involves removal of burned skin preserving the underlying viable deeper part of the dermis. The exposed deep dermis must be immediately covered by a thin split skin graft. Desiccation of the deep dermis post excision will lead to the loss of the exposed dermis. This technique, which put early excision of the burn wound on a firm footing, was introduced by Janzekovic. Working alone in erstwhile Yugoslavia in the 1960s, she observed that deep skin graft donor sites could be covered by thin split skin graft taken from another area for early and quality healing. She extended this concept to deep dermal burns by serially excising thin layers of burnt skin until viable skin was reached. It was covered with thin split skin graft. She treated 2615 patients and showed that they went back to work earlier. It is highly recommended for the management of upper extremity burns, particularly dorsal hand burns. The burn most suited for this technique is where the burnt skin looks pale white, does not blister or blisters late, does not blanch and, if it blanches, the color takes a long time to return or not at all. Such burns usually take more than 3 weeks to heal without infection and could lead to scarring and deformity. Tangential excision of burns is done between the third and fifth days post burn, before infection sets in with healing of the wound in two weeks.

The surgery is done under tourniquet and, using any of the hand held dermatomes, the burnt skin is serially shaved until good bright, healthy dermis is seen. On release of the tourniquet, the area must show spotty bleeding. Areas which do not show bleeding are marked, tourniquet reinflated, and further excision done in those areas. This sequence is repeated until all the involved areas are excised to the desired depth. Hemostasis is achieved by adrenaline-soaked pads. Alternatively, the major bleeding points are coagulated, tourniquet inflated, the raw area is covered with graft, gentle pressure dressing applied, the tourniquet is then deflated while the hand is kept elevated. The raw area is covered with thin split-thickness graft to obtain good results. Since some part of the dermis is preserved, minute inclusion cysts occur later from the secretion of the glands in the deeper part of the dermis. With thin grafts it is easily possible to just press them and release.

Dressings are done after a week if one is sure of hemostasis, and wounds heal in two weeks. All grafted areas undergo therapy with range of movement exercises and compression garments. This gives excellent results with preservation of body contour.

Fascial excision

In full-thickness burns, excision of the burnt skin would expose the fat, which offers a poor bed for grafting. If the extremity burn is part of a major burn, episodes of sepsis lead to ischemic necrosis of the burnt skin due to poor peripheral perfusion in the subcutaneous fat, leading to invasive sepsis. In such instances, excision to fascia is recommended. Fascial excision offers the advantage of easier hemostasis, since only major perforators need to be ligated. The significant disadvantages are contour deformity, which is unavoidable, and distal lymphedema, which can be managed with compressive garments and therapy.

In isolated upper limb burns, donor sites for autograft procurement are adequate. When upper limb burns form part of a major burn, saving of life becomes a priority and the timing of excision is dictated by the overall management of the patient. Further hand burns need a good amount of quality skin for cover. Flexibility, elasticity, and durability of grafted skin are dependent upon the thickness of the dermis present in the graft. Full-thickness excision of burns and coverage with split-thickness graft leaves a surface which is non-pliable and stiff. Introduction of dermal regeneration template like Integra offers a good alternative. Introduced in 1981 by John Burke and Ioannis Yannas, the artificial skin consists of two layers, an outer silastic epidermis to retain moisture and a deeper collagen–chondroitin sulphate dermis. The texture and porosity of the deeper layer allows ingrowth of tissue into the dermal matrix in 2–3 weeks, and a thin split-thickness autograft is placed over after removing the silastic sheet. The take of the graft is improved by using negative pressure wound therapy. In the long term, it has been found that the resultant skin is pliable and aesthetically very acceptable. The limiting factor in the use of Integra is high cost, and so it is used more in small burns, particularly in the hand where the ultimate pliability of the graft is important for function.

Salvage surgery in acute fourth degree burns

The upper limb could be severely burnt with damage to the deeper structures, sometimes up to the bone. This happens in epileptics during their convulsive episodes or in industrial injuries when the hand gets trapped in hot surfaces. Undertaking staged reconstructive procedures is worthwhile and is recommended when there is an overall small percentage of total body surface area of burns. The loss often happens on the dorsal surface of the hand and forearm. When skin over the dorsum of the IP joints is burnt, it is advisable to maintain the IP joints in extended position to promote skin healing and avoid necrosis of extensor insertion and volar subluxation of the extensors. It is not easy by splinting alone, and so oblique K-wires are placed to keep the IP joints in extension. This will prevent the development of boutonnière deformity at the proximal interphalangeal (PIP) joint. If there is composite loss including extensors in the fingers and hand, good debridement and pedicled flap covers are done. When joints are open, K-wires are used to stabilize them in neutral position before flap cover. Arthrodesis of the IP joints is not attempted in the primary situation. Priority is given for primary wound healing. Joints which remain unstable after the flap settles undergo arthrodesis in functional position at a later stage. Reconstructed hands, even in severe burns, functionally fare better than amputation with prosthesis fitting, making reconstructive attempt worthwhile.

Correction of post-burn deformities of the hand

The architecture and the functional mechanisms of the human hand are so intricate that deformities can occur in a hand burn in spite of good primary care. The extent of deformities could be very severe requiring multiple staged procedures in the absence of good care. Following three decades of managing post-burn hand deformities, many of them severe, at Ganga Hospital, these general principles guide our planning and execution of correction of post-burn deformities of the hand:

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  When reconstructing a post-burn hand deformity, the surgeon must concentrate more on increasing function than on increasing the range of movement of individual joints .

  For effective function the surgeon must restore pinch and power grip and the ability to grasp large objects. This is feasible when the thumb pulp meets the pulp of the other fingers. The hand must have adequate first web space, and the position and the movement at the metacarpophalangeal joints must allow the thumb to meet the fingers. Surgical procedures must be chosen with these goals in mind. For instance, it might be an advantage to have a PIP joint arthrodesed in good functional position so that the fingertip meets the thumb rather than perform complex procedures to restore movement in a bad swan neck deformity. In a hand with contracture, on average at least 10 joints are involved, and hence the principle is not to concentrate on the movement of individual joints but concentrate on function.

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  Assess the deformity in each tissue component and make the reconstruction plan with overall function in mind .

  Burn deformities occur primarily due to skin loss. But the deformity correction involves not only correcting the skin loss but also the secondary changes that have occurred in the musculotendinous units, joints, and the length of the vessels and nerves. They usually are the limiting factors for deformity correction. For example, severe flexion contractures are more challenging to treat than extension contractures since flexion contracture release could stretch vessels and nerves, which could risk the viability of the fingers or hand, whereas extension contractures do not share that risk. Evaluate the deformity in each of the components of skin, tendons, bone and joints, blood vessels, and nerves while making the treatment plan.

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  The correction achieved at the time of surgery will most probably be the maximum that will be achieved .

  The power of the scar in burn contractures to cause recurrence is frequently underestimated. A common cause of recurrence is inadequate release at the time of the original operation. Complete release and soft-tissue cover must be achieved whenever possible. While good postoperative splinting and therapy help to maintain the gains of surgery, they hardly can increase the range of movement than what was obtained on the table. So, one must go for maximum possible release at the time of contracture release.

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  It is the extent of release of contracture that matters more to the outcome than the type of cover provided

  This is to re-emphasize the point of the need for good release. Merely excision of the graft or scar and its replacement by a flap will not help restore function. The joints must be positioned well. The type of cover provided will depend upon the bed and the location of the defect. Over the palm thick skin grafts are preferred to bulky flaps since flaps in the palm prevent grasping of objects. The cover provided must help to heal the raw areas as early as possible since timing of the start of physiotherapy and its intensity will depend upon the complete take of the graft or flap. It is advisable to regraft spotty raw areas rather than allow secondary healing. Waiting for spontaneous healing continues the need for dressings and delays institution of good scar control measures like massage and splinting. Spontaneous healing of spotty raw areas is one of the causes of recurrence of the deformity.

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  When the deformity correction would need multiple staged procedures, first do the set of procedures which would maximally benefit the patient .

  Patients with severe deformities would need multiple staged procedures. When it involves the whole upper limb, proximal contractures are released first, one attends from axilla distally. When the hand is only involved, one must choose the set of procedures that would maximally help the patient to regain function. This will help them to regain confidence, increase compliance with therapy, and accept further procedures. Release of the first web space and achieving flexion at the metacarpophalangeal joints are usually the key procedures which would come under this category.

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  Timing of surgery is crucial for good outcome .

  It is felt that contracture release is best done when the scars are mature, as indicated by the subsidence of induration and the scars becoming pale. That usually takes about a year from the time of injury. While that concept is true, we have now gradually started to release the contractures earlier, particularly in children. The longer the joints are deformed, the deformity becomes severe, and in children it progresses fast. The adaptive shortening that happens in musculotendinous units becomes a challenge to correct, and sometimes it is impossible without their division. Further, the articular cartilages for their integrity need to be in contact with a cartilage surface. When the joints remain dislocated, the articular cartilages get covered by soft tissue and lose their integrity. So, if the deformity is severe or when it occurs in children and splinting is not of much help, early intervention is preferable. While obtaining full release is important, it need not be equated to full excision of the thick and hypertrophic scars. The thick hypertrophic scars in between the incisions in the course of time become supple with compression and therapy and yield when the tension forces are released.

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  Concentrate also on the aesthetics of reconstruction .

  Guy Foucher is supposed to have said that “hand surgery is also aesthetic surgery”. Nowhere is that concept more appropriate than in the correction of the deformities of the hand. The hand is an exposed part of the body in all cultures, and an acceptable appearance will help in easier and earlier integration of the individual into the society. This might involve performing procedures to correct minor issues. We have a low threshold for recommending Z-plasties to break the scar of the flaps, correction of web creep, use of laser, and accessories for scar improvement.

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  Provide comprehensive care under one roof .

While correction of severe deformities start with surgery, the maintenance of gains of surgery would need extensive therapy for scar control and prolonged wearing of splints and compression garments. It may take months to achieve the end result. During this arduous process, the patient’s compliance with therapy and their confidence in future is restored if they feel that caregivers are all working as one team. This happens if all the facilities needed are available under one roof and all the involved personnel review the patient together periodically.

Burn contractures of the hand have been classified by McCauley ( Table 19.1 ).

Management of individual deformities

Dorsal hand contractures

This is a common deformity since the dorsum of the hand is more often involved at the time of burn injury and due to the effects of edema in the dorsum of the hand. Protracted edema in the dorsum of the hand causes hyperextension of the metacarpophalangeal joints. The palmar arches flatten. Flexion of the PIP joint occurs as a result of edema-imposed tension on the common digital extensor tendon system and concurrent hyperextension of the MP joints. The ring and little fingers are more often affected. With time the deformities become fixed. The frequently associated first web contracture increases disability. The thumb does not meet the fingertips, making pinch and grasp impossible.

The principle of correction is to achieve full flexion of the MCP joints and get the IP joints as straight as possible. The flexion deformity at the IP joints is first assessed. If flexion deformities at the IP joint are fixed, they first need to be corrected. Otherwise, the release of the dorsal MCP joint extension contracture will bury the fingertips into the palm making the disability more severe. If, after flexion deformity release at the IP joints, the raw area would take skin grafts then one can go ahead with the release of the MCP joints. If the volar surface of the fingers would need a flap then it will be prudent to do that and then release the dorsal contracture in another sitting. The IP joint wounds need temporary stabilization with K-wires in neutral position. Our experience has shown that whenever the volar release needs a flap cover, the dissection is extensive, and further release incisions on the dorsum of the hand might compromise blood supply and venous drainage.

Dorsum contracture release is started by making a transverse incision a few centimeters proximal to the line of the MCP joints, so that after release the distal skin flap would slide over and still cover the MCP joints. Capsulotomy of the MCP joints can be done beneath the flap, and the dorsal raw area can be covered with graft. Achieving articular congruity of the joint surfaces after release is important. There is a larger articular surface on the volar aspect of the head of the metacarpal to accommodate the base of the proximal phalanx on flexion. The capsule is lax, and the pouch allows gliding of the base of the proximal phalanx over the head of the metacarpal. In long-standing contractures, this pouch of capsule is lost, and adhesions develop so that on attempted flexion of the joint, the joint dislocates. When closed maneuvers are used, the abnormal position may not be recognized. This is a frequent cause of recurrence of the deformity and poor outcome. In such circumstances, with a curved instrument adhesions have to be released, and a pocket has to be created on the volar side, for gliding of the base of the proximal phalanx, and the joint stabilized in that position until wound healing ( Fig. 19.2 ).

Long extensor tightness is another issue to be addressed. It can prevent full release. This is due to the adaptive shortening of the long extensors. One way is to do incremental release of the dorsal contracture. But now we prefer to release them as much as possible and if needed lengthen the extensors in the segment extending from the wrist to the origin of juncturae tendinae. In extreme circumstances we have divided the extensors to achieve the correction and patients have done satisfactorily without secondary extensor reconstruction. Division of the extensor in such circumstances has to be done proximally at the level of the wrist so that the distal stump is available if future tendon transfers are considered. When extensive work is done for release, the resultant raw area will almost need a flap cover. Skin flaps are preferred to facilitate future access for secondary reconstruction. We prefer a distant flap like the groin since that area is usually not involved even in major burns, and aesthetics of dorsal reconstruction play a part in patient satisfaction ( Fig. 19.3 ).

Volar hand and digital contractures

Volar contractures are more common in children since they accidentally hold hot objects, whereas dorsal burns are common in adults. Volar contractures of the fingers and thumb are more difficult to correct, particularly if they are long-standing in nature. The release may not always be full, and the resultant raw area will need a flap.

Incision release is done by cutting across the contracture, and gently the contracture is released. The vessels and the nerves get exposed and often limit the extent of contracture release. When the maximum possible release is obtained in the digits, the IP joints are stabilized by K-wires placed oblique across the joint. The tourniquet is then released, and the viability of the fingertip is assessed. If the fingertip remains pale for more than 5 minutes, the K-wire is released, and the joint is gently flexed to the level when the fingertip becomes pink again. Contracture release is accepted at that level, and the K-wire is again passed. If the bed would accept a graft, most often a full-thickness graft or thick split skin graft is applied for volar defects ( Fig. 19.4 ). If neurovascular structures and tendons are exposed, and the raw area is limited to a single finger, it is covered by a cross-finger flap ( Fig. 19.5 ). Large cross-finger flaps can be raised to match the defect. When adjacent fingers are involved we prefer a distant flap, which can be separate for each finger. Rarely, a single flap can be used after syndactylizing the released fingers and fingers separated in stages.

Burns of the palm are rare. If palmar contracture occurs post release, cover by a full-thickness graft or a thick split skin graft is preferred. Bulkiness of a flap prevents cupping of the palm, and the patients feel that they are already holding some objects. Flaps, if they have to be done, have to be thin or multiple thinning procedures have to be done. On the other hand even if multiple sittings of graft have to be applied ultimately grafts are preferable in the palm than a flap.