Musculoskeletal Trauma
General Considerations
Whether via monkey bar falls or trampoline accidents, children often find a way into the operating room for the treatment of musculoskeletal injuries. Approximately 40% of boys and 25% of girls will have at least one fracture before the age of 16. Upper extremity fractures account for two-thirds of fractures in children with the radius being the most commonly involved . Surgical repair or reduction under general anesthesia is indicated in approximately 20% patients; the indications for emergent operative repair include neurovascular compromise and open fractures. Non-emergent operative repair is often required for fractures that include the growth plate, fractures that cannot be effectively reduced noninvasively, or complex fractures of the leg and ankle. Surgical repair ranges in complexity from closed percutaneous pinning (e.g. for supracondylar fractures) to open pelvic or femoral fracture repairs with the potential for significant blood loss.
Children who require emergent surgical reduction for acute fractures are considered to have “full stomach” status and should be managed with a rapid sequence technique (or modified rapid sequence depending on the clinical situation) and tracheal intubation. Children who present for elective repair and have adhered to standard fasting guidelines are at low risk for pulmonary aspiration of gastric contents, unless there are other reasons for delayed gastric emptying such as recent opioid administration. Therefore, any anesthetic or airway management technique is feasible. Pelvic and lower extremity fractures may be associated with a significant amount of blood loss. Obtaining a baseline hemoglobin level may be prudent depending on the magnitude of the injury or the risk for intraoperative bleeding. Postoperative pain management for surgical repair of acute fractures can be facilitated through a variety of approaches including nonsteroidal antiinflammatory medications (e.g., ibuprofen, ketorolac, etc.), acetaminophen, muscle relaxants (e.g., diazepam, tizanidine, baclofen, etc.), or opioids for a limited period of time. Peripheral nerve blockade with or without a continuous catheter technique may also be advantageous. If a regional anesthetic is used, appropriate monitoring is vital to ensure early detection of compartment syndrome.
Supracondylar Fractures
The most common elbow injury in children requiring surgical repair is the supracondylar humeral fracture. It is associated with neurologic injury (10%–15%) and vascular injury (20%). Neurologic injury is typically traction neuropraxia and resolves over time. Vascular compromise of the brachial artery can result in diminished or absent distal pulses which must be treated emergently if blood flow fails to improve with closed reduction. Closed reduction and pinning is the preferred mode of treatment for displaced elbow fractures. However, open reduction with vascular exploration may be required when the fracture is associated with diminished or absent pulses. The anesthetic management is dictated by the acuity of the injury and the presence of neurovascular compromise. Patients brought to the operation room (OR) emergently for operative reduction should be treated as a full stomach and intubated with a rapid sequence technique. Conversely, an appropriately fasted child, with a stable fracture, can be managed with a supraglottic airway device.
Spica Cast Placement
One strategy for management of acute lower extremity fractures in children is the spica cast, which extends from above the hip bones down to variable locations of the lower extremities. A spica cast can be used to immobilize fractures or deformities involving one or both lower extremities or stabilize fractures of the pelvis. Because it is typically used for preschool-aged children, general anesthesia is required to optimize proper fitting. The child is placed upon an elevated “spica box” during the procedure; therefore airway management usually consists of tracheal intubation or placement of a securely fitting supraglottic airway. The surgeon may request muscle relaxation to assist with skeletal reduction. As the surgeon begins to apply the spica cast, a folded towel is placed under the upper portion of the cast to ensure sufficient space between the child’s anterior abdominal wall and the cast ( Fig. 25.1 ). Severe postoperative pain or discomfort should prompt examination for a tight or poorly fitted cast.
Slipped Capital Femoral Epiphysis
A unique pediatric musculoskeletal disorder that can present acutely is slipped capital femoral epiphysis (SCFE). Although not specifically a traumatic injury, this hip disorder involves displacement of the femoral head relative to the femoral neck and shaft and most commonly affects obese prepubertal children. It is likely that the combination of physical weakness and/or abnormally large physiologic loads (e.g., obesity) across the physis contribute to the development of this condition. SCFE is associated with pain and the potential for osteonecrosis of the femoral head as the blood supply to the femoral head can be compromised by the displacement of the femoral head. Surgical intervention is typically performed soon after diagnosis. The most common approach involves percutaneous fixation of the femoral head and neck with a cannulated screw to prevent further displacement.
Developmental Dysplasia or Dislocation of the Hip
Developmental dysplasia or dislocation of the hip (DDH) includes all cases of dysplasia, subluxation, or dislocation of the hip joint. The term DDH has gradually replaced the term congenital dysplasia or dislocation of the hip because it is more representative of the range of hip abnormalities that can present in infancy or childhood. DDH has both genetic and environmental factors and it is more common among females (80%) and infants born in the breech presentation. DDH should be treated early in infancy with bracing techniques that immobilize the affected hip and stabilize the relationship between the femoral head and the acetabulum to facilitate normal development. If the hip remains unstable or if the pelvic anatomy is not amenable to closed reduction, surgical correction consisting of an open reduction with a femoral or pelvic osteotomy may be indicated. Adductor muscle release may also be performed.
Correction of DDH in infants is not associated with significant blood loss. Placement of an endotracheal tube should be considered as patients are typically placed in a spica cast or brace at the conclusion of the procedure, which may necessitate patient movement. Regional anesthesia for postoperative pain control is not necessary if reduction of the hip has been accomplished without invasive surgery. Depending on the extent of the surgery, postoperative analgesia can be accomplished by intraoperative infiltration of a local anesthetic or administration of peripheral or neuraxial block with or without a catheter in addition to systemic analgesic medications.
Spinal Deformity
Spinal disorders can range from the otherwise healthy adolescent presenting for correction of slowly progressing scoliosis to the critically ill infant presenting with restrictive lung disease and pulmonary hypertension secondary to thoracic insufficiency syndrome. Careful surgical and anesthetic planning tailored to patient-specific anatomy and physiology is critical to ensuring positive patient outcomes.
Scoliosis is characterized by a curve of the spine in the frontal plan, which can include the thoracic vertebra, lumbar vertebra, or both. This leads to rotation of the spine and corresponding ribs which produces the characteristic chest wall asymmetry. In mild forms, scoliosis can produce a marked deformity of the trunk which, if allowed to progress, can lead to significant cardiopulmonary impairment. Scoliosis can be congenital, early onset, or idiopathic (typically presenting in adolescence), secondary to neuromuscular disease (cerebral palsy, Duchenne muscular dystrophy, and others) or secondary to systemic disease or syndromes (Marfan syndrome, neurofibromatosis, and others). The etiology of the scoliosis, rate of progression, and age at onset will influence the surgical management.
Early onset scoliosis and adolescent idiopathic scoliosis (AIS) are initially managed with bracing to prevent progression of the deformity. When this is unsuccessful, surgical interventions may be indicated. For scoliosis in younger children who have not yet achieved skeletal maturity, the spine can be stabilized with growing rods that allow for future sequential expansions to ensure adequate thoracic development. Once these patients have achieved skeletal maturity, they typically require posterior spinal fusion. Conversely, adolescents, who have reached skeletal maturity and failed bracing, will be managed with spine fusion primarily. A common measurement of spinal deformity is the Cobb angle, which represents the greatest angulation in a region of the spine. It is measured by drawing intersecting lines from the superior endplate of vertebrae at the top of the curve and the inferior endplate of the vertebrae at the bottom of the curve. A Cobb angle of 10 degrees is required for a diagnosis of scoliosis and when a curve progresses to 45 to 50 degrees or higher, surgical intervention is typically indicated.
Children with neuromuscular diseases such as cerebral palsy or various muscular dystrophies will commonly present for spinal fusion. The combination of diffuse muscle weakness and static or progressive limitations in the ability to ambulate leads to a high rate of scoliosis, with up to 95% patients with Duchenne muscular dystrophy developing progressive scoliosis during their lifetime. The primary reason for repairing the spines of these debilitated children is to allow them to sit upright without assistance, thus decreasing the incidence of chronic pulmonary aspiration, increasing their quality of life, and possibly extending their life expectancy. The most extensive surgical procedure performed in these children is when the spine is instrumented from T1 to the sacrum. These procedures typically involve greater blood loss than for idiopathic repair with the potential for patients to lose 1 to 3 blood volumes. The reason for this increased blood loss in patients with cerebral palsy is not fully understood but it may be related to abnormalities in factor levels and abnormalities in platelet function. Real-time coagulation with assessment of coagulation function with thromboelastography can help guide replacement therapy, and these patients may benefit from the early use of blood and fresh frozen plasma.
Preoperative Considerations
For otherwise healthy patients presenting with early onset scoliosis or AIS, routine pulmonary function testing or cardiac evaluation are likely not necessary as long as there are no concerning functional limitations and the spinal curve is less than 80 degrees. Conversely, patients with severe cerebral palsy or muscular dystrophy may suffer from preoperative respiratory insufficiency and require supplemental respiratory support preoperatively (bilevel positive airway pressure [BiPAP], continuous positive airway pressure [CPAP], etc.). In those patients, pulmonary function testing can help identify patients at risk for postoperative respiratory complications. Coordination with the patient’s pulmonologist can help guide postoperative respiratory care and minimize acute respiratory complications (failed extubation, atelectasis, and others). Similarly, providers should have a low threshold for assessing cardiac function in the patient populations at high risk for cardiomyopathy, including Duchenne muscular dystrophy and Friedreich ataxia. Routine echocardiography in all patients with cerebral palsy presenting for spine fusion is unlikely to reveal clinically relevant cardiac abnormalities.
Preoperative laboratory evaluation can include a complete blood count, blood chemistry, coagulation studies, and a type-and-cross though there is little consensus on the relative value of perioperative laboratory assessments such as blood chemistry and coagulation studies in AIS patients. Historically, autologous or directed-donor blood donation was used to reduce the risk for allogenic blood transfusion in this population and, in recent years, the use of intraoperative cell salvage and antifibrinolytic therapy have been shown to reduce the need for allogenic transfusion.
A thorough discussion should take place with the family and patient about the nature and risks of the anesthetic, the surgical procedure, and any neurophysiologic monitoring. If an intraoperative “wake-up” test is planned, the procedure is discussed in detail with the patient to facilitate intraoperative success. The patient and family should also be told that it is common for their face to be swollen postoperatively, and that it will subside over the first two postoperative days.
Intraoperative Considerations
Patients can undergo either an inhalation or IV induction depending on patient and provider preference. Patients are usually induced on the transport bed to simplify turning the patient to a prone position on the OR table ( Fig. 25.2 ). Tracheal intubation can be facilitated with a bolus of propofol and an opioid so as to avoid neuromuscular blockade in anticipation of neuromonitoring. After tracheal intubation, and before turning the patient prone, all the necessary monitors and lines are inserted. This includes a urinary catheter, orogastric tube, esophageal temperature probe, two peripheral IV lines, arterial line, and neuromonitoring leads. An arterial line is used for close hemodynamic monitoring and laboratory assessments. The ulnar artery should not be cannulated if the radial artery on the same side was punctured or if a hematoma of the radial arterial site develops. Early decision to abandon a failed site because of arterial spasm or hematoma and move to the contralateral side can help save time and avoid injury. A central line is not usually required for AIS patients but may be necessary for children with neuromuscular disease because of underlying medical conditions or challenges with securing adequate peripheral access. Finally, careful attention should be paid to securing the endotracheal tube and protecting the eyes. A soft bite block should be placed between the teeth to prevent trauma to the tongue.
