Rockwood, Green, and Wilkins' Fractures, 10e Package

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CHAPTER 6 • Compartment Syndrome in Children

management is also recommended, as shock and hypoxia may lower tissue pressure tolerance. 12 If the diagnosis of compartment syndrome is made, emer gent fasciotomy should be performed. At times, release of the epimysium is also necessary. Necrotic tissue should be excised. If in doubt as to the viability of soft tissue, questionable tis sue should not be debrided at the index procedure because the potential for tissue recovery in a child is substantial. 10 Via ble tissue will be pink and perfused and muscle will conduct electric current. If tissue is obviously not perfused and is gray, brown, or black, malodorous, and does not conduct current, it may be necrotic and should be debrided to avoid becoming colonized with bacteria. If unsure of viability, allow time for the tissue to declare itself. The patient should subsequently return to the operating room for serial assessments, debridements, and ultimately, closure. Late fibrosis of necrotic muscle can lead to compression of the adjacent nerves and result in disability of the extremity. Other procedures may be indicated based on the etiology of the compartment syndrome, including fracture reduction and stabilization, vascular thrombectomy, repair, or grafting and nerve exploration. Nerve repair or reconstruction should be performed at the time of definitive wound closure. In the case of a delayed compartment syndrome where there is no demonstrable muscle function in any segment of the involved limb, the limb can be splinted in a functional posi tion. Fasciotomy is not indicated. For the upper extremity, if resources are available for immediate reconstruction with func tional free muscle transfer, then early debridement and recon struction can reduce the incidence of late contracture and can improve neurologic recovery. 36,42 Supportive care, usually in the form of vigorous IV hydration, should be given for the poten tial risk of myoglobinuria. Myoglobinuria, as well as metabolic acidosis and hyperkalemia, can also occur during reperfusion and requires medical management to prevent sequelae such as renal failure, shock, hypothermia, and cardiac arrhythmias and/or failure. In the upper extremity, compartment syndrome most com monly involves the forearm and is typically associated with both bone fracture of the forearm and supracondylar humerus (SCH) fracture. 5,14 The incidence of forearm compartment syndrome following upper extremity injuries has been estimated at 1%. 12 One national study identified 31,167 patients with SCH frac tures of whom 0.2% (67/31,167) developed compartment syn drome. Neurovascular injury was associated with compartment syndrome in 4.5% (24/530). 33 For example, SCH fractures with a median nerve injury are at high risk for compartment syndrome, as the pain of compartment syndrome is masked. 24 High-risk fracture patterns include displaced SCH fractures with concomitant ipsilateral forearm fractures, known as the floating elbow. In this case, the rate of compartment syndrome is as high as 33%. 5 Operatively managed Monteggia and Monteggia frac ture equivalents had a higher rate of compartment syndrome UPPER EXTREMITY

at 15.3% (9/59) when compared to operatively managed type three SCH fractures where compartment syndrome occurred in 0.9% (2/230). 15 Other risk factors for developing compartment syndrome include longer intraoperative and fluoroscopic times and male sex. Some studies have suggested younger age is a risk factor for compartment syndrome, while a national study has reported older pediatric patients are at higher risk. 5,23,33,51 Intraoperative examination and pressure measurements should be used to determine what compartment is affected and where to do a fasciotomy. For example, if the arm is affected, decompres sion of the volar forearm may adequately decompress the arm so that the dorsal forearm does not require a fasciotomy as well. The surgical incision for fasciotomy of the arm and forearm is extensile from the brachium to the carpal tunnel. The extent of the release performed is tailored to the clinical and intraopera tive findings. Release of the dorsal forearm and compartments of the hand requires separate incisions when indicated (Table 6-2). Separate incisions for dermatomes of each finger may also be added to prevent skin necrosis and loss of fingers. ARM The anterior and posterior compartments of the arm can be decompressed through a single medial incision. This allows access to the neurovascular structures of the arm, the medial fascia of the biceps and brachialis in the anterior compartment, and the fascia of the triceps. Excision of the medial intermuscu lar septum will provide additional decompression of both com partments (Fig. 6-1). The incision can be extended to the elbow crease and incorporated with the incision for decompression of the forearm. This also allows release of the lacertus fibrosus and evaluation of the distal portion of the brachial artery. When there is no need to evaluate and decompress the neurovascular structures or extend the incision into the forearm, straight mid line anterior and posterior fasciotomies may be performed to decompress the flexor and extensor compartments, respectively. FOREARM Several skin incisions have been described for the forearm. Since the surgical incisions are long and extensile. Almost any incision can be used to decompress the forearm compartments (Fig. 6-2). Because the incisions are left open, we prefer the incision described in Figure 6-3C,D over the incision seen in Figure 6-3A,B, as this minimizes exposure of neurovascu lar structures and can be extended proximally into the medial arm and distally into the carpal tunnel. After the skin incision is made, the antebrachial fascia is opened longitudinally from lacertus fibrosus to the wrist flexion crease. This decompresses the superficial flexor compartment. The deep flexor compart ment is most easily and safely exposed through the ulnar side of the forearm. 34 Start at the mid- to distal forearm and identify the interval between flexor carpi ulnaris and flexor digitorum superficialis. The flexor digitorum profundus and flexor pollicis longus fascia are exposed and released through this interval. This is the most important component of this procedure, as the deep flexor compartment is usually the first and most affected