Pediatric mutilating hand injuries

Types of injures 

The diversity of mechanisms of injury leads to a multiplicity of types of injuries in the pediatric mutilated hand. The mechanisms of mutilation include meat grinders, saws, stationary bicycles, doors, hinges, explosives, guns, firecrackers, dog and other animal bites, burn injury from both hot water and exposed heating elements or electricity, and lawn mowers [2], [3], [4], [5]. Unfortunately, children's mutilating injuries tend to be less amenable to replantation than the typical hand saw injury seen so commonly in adults. As a result, children frequently need secondary operations to maximize function and appearance.

Initial management and preoperative evaluation 

Frequently, when a child has had a devastating injury to an extremity, most of the attention is focused on the injured part. Frantic parents and friends often make it difficult to assess the entire patient in the emergency room. As is true with any emergency patient, the ABCs (airway, breathing and circulation) are addressed first.

Unlike an adult, a young child often is unable to give a reliable history and may be unable to describe pain successfully in other locations. Unfortunately, if the child is too young, the history must then be obtained from a witness, either a parent or possibly the ambulance crew that arrived on the scene. Key elements in the history include the nature of the injury, mechanism of injury, and the possibility of contamination. Sometimes the mechanism is quite obvious (Fig. 1). If there has been a crushing or avulsion element to the injury, the surgeon must be concerned about a more proximal injury, such as muscle tearing in the forearm and possible delayed compartment syndromes. Severe contamination from farm injuries needs more aggressive debridement and perioperative antibiotics that cover gram-negative bacteria. Obviously, any chronic medical condition that precludes a long general anesthesia also needs to be determined.

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Fig. 1. (A) A 6-year-old child with his hand caught in a meat grinder. (B) The grinder was removed using a carbon cutting circular saw. The patient has a severe mutilating injury. (C) The small finger was salvaged; all carpal bones on the radial aspect of the hand had to be removed. (D) Great toe to thumb transplant (proximal phalanx of the toe to the distal radius) to create prehension. (E,F) The child can now swing a baseball bat, write, and use eating utensils with his reconstructed right dominant hand.

A thorough general physical examination is very important. The evaluating physician should have a low threshold for obtaining radiographs of any potentially injured part or tender site on the body.

With regard to the injured limb, key elements of the examination in the emergency room before taking the patient to the operating room can often be performed with the dressing intact. If there has been an injury to the proximal fingers, mid-palm, wrist, or forearm the examining surgeon may be able gently to examine the tips of the fingers for vascularity, sensation if the patient is old enough to cooperate, and any voluntary motion. Sensory examination may be the most helpful preoperatively, because the surgeon may not need to dissect as extensively for nerve injury intraoperatively if sensation is intact. Particularly in young children, however, the trauma of examining an obviously mangled extremity must be weighed against the unlikely possibility of obtaining any clinical information that helps with the emergency operation.

In cases of amputation, a quick evaluation of the amputated part can be performed in the emergency room under loupe magnification to alert the patient's parents of nonreplantable limbs or digits. Every effort should be made, however, to attempt replantation in children.

Religious and cultural issues are often apparent in the emergency room when discussing treatment with the parents. For example, certain religious groups do not believe in blood transfusions. If replantation or revascularization is contemplated in such a child, the parents should be alerted that the child will probably need blood transfusion sometime during the hospitalization. The parents may elect to have the child not undergo replantation in such a circumstance.

Because of cultural issues in the Asian population, the authors have frequently replanted mutilated parts that they were sure would have a poor functional outcome. According to some Asian cultural philosophies, however, if an individual dies without all of his or her body parts they have somehow disgraced their ancestors. The authors have many happy Asian patients with stiff fingers.

The initial assessment of the injured extremity and amputated part is then completed in the operating room when the child is under general anesthesia. Once a complete evaluation of the mutilated extremity is performed in the operating room, the surgeon may take a short break from the procedure and discuss the examination with the anxious parents. Certainly replantation and revascularization should take precedence over allaying parental anxiousness. Decisions should be made with the parents' assistance, however, if at all possible.

Many patients are transferred to a replantation center from several hours away. During the preparation for transport of the child, several steps should be performed before the patient's transfer. Specifically, the patient should be hemodynamically stable before transfer. The injured extremity should be wrapped with a bulky dressing wrapped tight enough to prevent continuous oozing from the hand but not so tight as to cause pain or vascular compromise. A tourniquet should not be placed on the extremity. The amputated part should be wrapped in slightly moistened saline gauze. It can then be placed in a plastic bag or a water-tight container and placed on ice. Care should be taken not to place the part directly on ice without a protective layer of gauze or directly in ice to avoid freezing the part. Placing the part in soaked saline sponges or allowing the part to float in saline leads to maceration of the part.

The operative procedure: general concepts 

If available, the authors often try to have two operative teams working simultaneously in major amputations. The amputated part is taken to the operating room while another team is evaluating and preparing the patient for surgery. The so-called tagging team examines the amputated or mutilated parts under an operating room microscope and puts tagging sutures, specifically No. 6-0 silk, around structures to be repaired, such as digital arteries, nerves, and veins. Debridement of obviously contaminated tissue should be performed at the same time.

Once the patient is stable hemodynamically, he or she is brought into the operating room and general anesthesia begins. Usually the tagging team is working in the same room identifying structures on the amputated parts. A tourniquet is placed on the arm and the arm is elevated if severe blood loss is anticipated during dressing removal. The tourniquet may, however, need to be released to determine viability of damaged parts and the possible need for revascularization.

Debridement is then performed. If replantation or revascularization is necessary, debridement should be performed expeditiously to minimize ischemia time. Clearly infected, contaminated tissue needs to be removed. Marginally vascularized tissue of significant importance, such as nerves, tendons, joints, and bones, should be left intact. Muscle, devascularized fat, and skin should all be debrided aggressively. Debridement should be performed under tourniquet control. After release of tourniquet there should be good bleeding from the debrided edges; if not, more debridement should be performed. Skin bridges, which may provide critical venous drainage, should be preserved whenever possible. Superficial veins in subcutaneous tissue may be required in future reconstructive efforts, such as microvascular soft tissue coverage operations. The veins can be debrided definitively and immediately at the time of anastomosis.

Tendon debridement should be performed sparingly and paratenon should be preserved if at all possible for future skin grafting. Undebrided tendon ends are convenient grasping points while manipulating a tendon for tenorrhaphy. Bony ends must be debrided of foreign contaminated tissue before any osteosynthesis.

In patients who have suffered burn injuries or crushing injuries with avulsion, care must be taken not to remove marginally vascularized tissue. The authors believe in serial debridements over the next several days to maximize the amount of viable tissue available for reconstruction.

After debridement is completed, irrigation should be performed with bulb syringes or pulse lavage. Once irrigation is completed and hemostasis is obtained, the surgeon next needs to consider coverage of the wound. If primary closure cannot be obtained at the time of the emergency operation, then skin grafting is considered. Large skin grafts or emergency microvascular transplants, however, should not be performed unless the surgeon is sure of having adequately debrided the wound. This is often difficult in the mutilated extremity, because there frequently is a burn, crush, or avulsion component to the injury. What seems viable at the emergency operation may be necrotic 3 or 4 days later at a subsequent debridement operation.

To avoid desiccation of the wound with traditional wet-to-dry dressing changes the authors use a subatmospheric (VAC sponge) pressure dressing for wound management [6]. This system is well tolerated by patients. The system seems to keep the wounds moist and is especially well liked by the nursing staff who no longer need to do three to four times a day wet-to-dry dressing changes. The sponge is generally changed in the operating room.

Replantation and revascularization 

The concepts and techniques for replantation and revascularization in mutilating injuries in children are similar to those in adults [7], [8]. Once tagged, amputated parts are placed in a small operative basin that is then placed on ice to minimize warm ischemia. The second operative team performs debridement and at the same time identifies the corresponding structures that were previously identified in the amputated part by the tagging team, specifically arteries, nerves, veins, and flexor and extensor tendons.

The replantation-revascularization effort should begin with the most ulnar-amputated digit. The sequence of replantation begins with osteosynthesis [9]. Occasionally, in the situation where a large part has been amputated, like an entire hand, forearm, or upper arm, revascularization may be performed before osteosynthesis to prevent muscle ischemia. In this situation a T-shaped shunt is placed in the proximal and distal artery. The other end of the T is attached to a syringe containing heparinized saline. Once arterial inflow is established in the amputated part, osteosynthesis can be performed. The authors generally perfuse the part for about 20 minutes and then clamp off the shunt. Bleeding can be profuse during this time and the anesthesiologist should usually hang blood during such a reperfusion effort. To perform an end-to-end anastomosis of arteries, veins, and nerves, bone shortening is usually performed. Up to 3 to 4 cm can be removed from the radius and ulna or humerus without any significant functional loss in amputation injuries. Rigid plate fixation should be performed in long-bone repairs, being careful not to injure growth centers. In contradistinction, osteosynthesis of finger replants is generally preformed with K-wire fixation over plate fixation to speed along the replantation effort. Plates may also become exposed if there is marginal necrosis of the skin at the repair site.

Once osteosynthesis is performed in the large part replant, an arterial anastomosis is performed either with or without a vein graft, depending on the defect. Throughout this time the replanted part is allowed to bleed from the venous side. At first the blood that comes from the veins is quite dark in color, rich in muscle breakdown products. The authors usually allow this venous blood to drain for several minutes before venous repair. The patient may lose up to one to two units of blood during this time. The venous repair is not performed until the color and consistency of the venous outflow appear normal. Venous blood sampling for potassium has been reported: if the potassium is less than 6.5, then the risk of systemic injury is unlikely [10].

During any crushing or replantation-revascularization operation, the surgeon needs to be aware of possible compartment syndromes. This is missed easily in patients who have had avulsion injuries of the fingers and have had tearing at the musculotendinous junction in the forearm. The patient can develop compartment syndrome sometimes several hours after the injury. Revascularized or replanted arms or hands should be watched closely for elevated compartment pressures in the hand. Dorsal incisions should be made to release the intrinsic musculature by releasing the fascia in the intermetacarpal space. Compartment pressures can be measured accurately with the Stryker system (Stryker Surgical Division, Kalamazoo, MI) [11]. Compartment pressures above 25 mm Hg signal the need for compartment release. The surgeon, however, should have a low threshold for compartment release because edema and elevated pressures may develop several hours after surgery.

When replanting fingers vascular repairs often can be tedious and technically very difficult in children. Vein grafts [12] are used liberally in crushed and avulsed injuries. Resection of damaged vessels is very important to maintain the patency of a vascular repair.

In a very distal replant, for example distal to the distal interphalangeal (DIP) joint, arterial repair may be possible, but a venous repair may not. The surgeon should look for a volar vein or repair the distal artery to a proximal vein thereby using the second artery in the digit as outflow for the replanted part [13].

The use of a venous flow-through flap [14] can serve as a vein conduit and also act as soft tissue cover for an area of questionably viable skin on the volar or dorsal surface of a mutilated finger, as in ring avulsion injuries. The venous flap can be harvested easily from the volar surface of the wrist. Vein grafts can also be harvested from this area. The vein vessel diameter is approximately the same size as the arteries of the finger.

Next in the sequence of replantation and revascularization is the digital nerve repair. Usually after microvascular arterial repair, the nerve is in the operating field and nerve repair can be performed expeditiously. Digital nerve repair should be performed end-to-end if possible. A nerve graft can be placed in the primary emergency setting. If there is marginal necrosis and exposure of the nerve graft, however, one may lose the nerve graft and have lost a precious donor site. A nerve graft can be harvested from the superficial peroneal region on the dorsum of the foot [15] or the sural nerve region. Care should be taken to harvest the nerve high enough up the calf so that the patient does not develop a neuroma at the upper boot level. A nerve graft can also be harvested from the ulnar aspect of the forearm. Patients often complain, however, of numbness over the volar forearm. Vein conduits also can be used for nerve gaps. The patient can obtain similar results with a vein conduit as nerve graft if the defect is 3 cm or less [16].

Flexor tendon repair is next performed using a double-opposing locking loop stitch technique [17], [18] with or without epitendinous stitch depending on the contour and irregularity of the repair. If there is a tendon gap, a tendon graft can be used. One should avoid tendon grafts, however, if marginal necrosis of the skin is anticipated. The surgeon may be more inclined to use a tendon graft in a potentially problematic wound if tendon graft is harvested from a nonreplantable part. Grafts can also be harvested from the palmaris longus, plantaris tendon, or extensor digitorum longus to the middle three toes [12].

The next step in the sequence of replantation involves repairing extensor tendons and dorsal veins. After the volar skin incision is closed loosely, the hand is turned over. The extensor tendon is repaired using as strong a repair as possible. If there is adequate tendon, a double-opposing locking stitch should be performed. Alternatively, a mattress repair is usually adequate. Venous repair is performed under the operating microscope with vein grafts if necessary. In general, veins can usually be repaired in end-to-end fashion.

Once the replantation-revascularization operation has been performed, the patient is empirically started on low-molecular-weight dextran [19], [20] (total dose not greater than 20 mL/kg in 24 hours). Dextran is usually continued for 5 days. Heparin may be added as a second anticoagulant if a vein graft has been used of if there have been intraoperative thrombosis problems [21], [22]. The authors generally run heparin at 5 to 25 units/kg/h and titrate the dose to the clinical response. A loose, bulky dressing with a dorsal protective splint is then fashioned. Xeroform or any other nonadherent petroleum-based gauze should not be placed circumferentially around the finger, to avoid a tourniquet effect with swelling.

Monitoring is performed using quantitative fluorometry. A venous Doppler probe [23] is helpful for real-time monitoring of the circulation in large replanted parts or microvascular transplant.

Medicinal leeches are used when there is any sign of venous insufficiency or in severely bruised or traumatized soft tissue in the mutilated hand [24], [25].

Soft tissue coverage 

Adequate soft tissue coverage is essential to re-establish any reasonable functional result in a mutilated hand, especially in children. For small defects, such as fingertip avulsions with exposed distal phalanx, cross finger flaps or pedicle flaps may be of value. In a larger wound, however, especially if there is any crush or avulsion associated with the injured upper extremity, keeping the patient's hand in a dependent position for a groin flap may cause undue swelling. Young children may not tolerate pedicle flap or being in this uncomfortable position for the 2-week requirement.

Microvascular transplants of muscle with split-thickness skin graft coverage, cutaneous flaps, or fascial flaps with skin graft can serve as excellent coverage for immediate or delayed tendon, bone, nerve, or joint reconstruction [26]. Tendon repairs or tendon grafts may have less adhesion if tunneled through subcutaneous fat of a skin flap or through muscle rather than laying the tendon directly onto healing bone fractures [12].

The timing of soft tissue coverage is a controversial issue. Several others have recommended a strict time frame for definitive soft tissue coverage in mutilating extremity injuries [27], [28]. It has been the authors' experience that soft tissue coverage should take place when the responsible surgeon believes that the wound has been debrided adequately in a serial fashion. The authors have had a few cases of infection from inadequate debridement and early coverage of a wound that had been presumably deemed ready for coverage within 48 hours of the injury. With the use of the VAC sponge system, the problems with desiccation and loss of potentially viable tissue are no longer a significant problem.

Emergency microvascular coverage is probably indicated in the case where a portion of a nonreplantable part can be used as a microvascular transplant, either as an arterial-to-venous repair or a venous flow-through for soft tissue coverage. In those circumstances, a normal donor site is not wasted should a postoperative complication occur. Emergency toe transplants have been performed on the authors' service in specific, unique circumstances. For example, a child suffered a below-knee avulsion amputation with no injury to the foot and also had a nonreplantable thumb injury [29], [30]. In that situation the toe was harvested from the nonreplantable below-knee amputation and transplanted to the thumb position.

Delayed treatment of the mutilating hand injury 

Unfortunately, in many children who have undergone mutilating hand injuries, the surgeon may not be able to salvage any of the amputated parts. The patient is frequently deficient in soft tissue and has either lost all of their fingers or has one finger remaining. This is especially true in the meat grinder-type injury (Fig. 2). Restoring prehensile function or pinch is the goal [31], [32], [33], [34], [35], [36]. When the reconstructive surgeon is presented with a patient who has had this sort of injury, one needs to determine whether soft tissue coverage is adequate and whether there is adequate blood supply to transplant soft tissue and toes for finger and thumb reconstruction [37], [38]. When evaluating for possible toe transplantation, the surgeon needs to define whether digital nerves, flexor, or extensor tendons are available for repair to the toe. If all of this is present soft tissue and toe transplant can be performed simultaneously in the appropriate setting. Otherwise, a staged sequence of operations needs to be performed [39], [40]. In general, soft tissue reconstruction is preformed first followed by toe transplantation (Fig. 3, Fig. 4).

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Fig. 2. (A) A 10-year-old boy suffered a nonreplantable left middle finger amputation. (B) Markings for a second toe transplant for finger reconstruction. (C) Intraoperative image of second toe transplantation. (D,E) Postoperative demonstration of length and function.

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Fig. 3. (A,B) Late result of a mutilating injury of the right hand in a 4-year-old boy. (C,D) Intraoperative image of simultaneous great toe and rectus muscle transplant. (E,F) Immediate postoperative results with STSG over the rectus muscle. Venous Doppler probe is in place. (G,H) Nine months' postoperative view of function.

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Fig. 4. (A) Severe burn crush injury to 7-year-old girl. (B) Radiographs showing loss of all fingers. (C,D) Postoperative image of hand appearance and function after simultaneous right second toe and serratus muscle transplant and subsequent left second and third toe transplant.

Summary 

Mutilating hand injuries in children are a devastating problem. With aggressive efforts at replantation and revascularization, methodic debridement, timely soft tissue coverage, and early mobilization, however, the results in these unfortunate children can be quite rewarding. The child often does well with the functional aspect of recovery and rehabilitation but will probably hide his or her deformed hand from friends and family. These children generally become more shy and reserved.

The parents are the key to rehabilitation. A good relationship between the parent, the physician, and the hand therapist is essential for the best result. Interestingly, the parents who are the most demanding on the staff during the initial emergency period are often the most appreciative parents and their children often achieve the best result. Conscientious parents are the best advocates for their children.

Obviously, the prevention of these devastating injuries is much preferable to extraordinary heroic reconstruction. Unfortunately, some injuries are inevitable. It is nearly impossible to create an absolutely hazard-free environment for children. Potential injuries can be avoided, however, simply by keeping hazardous machines and equipment out of the reach of the child and by keeping children out of the potentially dangerous workplace.