This article reviews thoracolumbar injury patterns that may be seen in children. Although much of the management of these injuries has been extrapolated from the adult literature, unique surgical and nonsurgical considerations in treating children with thoracolumbar spine fractures are discussed. In conclusion, most children achieve satisfactory outcomes in long-term follow-up after healing.
Key points
- •
Compared with adult spine trauma, pediatric spine trauma is less likely to result in fracture due to the greater elasticity and compressibility of the pediatric spine.
- •
The anatomy, injury pattern, radiographic findings, and management of pediatric thoracolumbar spine trauma warrant special consideration.
- •
Among various thoracolumbar spine injuries, a major difference between adults and children is the occurrence of spinal cord injury (SCI) without radiographic abnormality (SCIWORA).
- •
The understanding of thoracolumbar spine injury in children is constantly evolving.
Introduction
Pediatric spine trauma is rare, with pediatric patients suffering only 2% to 5% of all spinal injuries. A majority of these are in the cervical spine. This is attributed to the proportionally larger head size in children, in addition to their weaker supportive soft tissue structures in comparison to those of adults. Thus, only an estimated 0.6% to 0.9% of all spinal trauma cases are pediatric thoracic and lumbar spine injuries.
Compared with adult spine trauma, pediatric spine trauma is less likely to result in fracture due to the greater elasticity and compressibility of the pediatric spine. Radiography may show subtler signs, such as splaying of spinous processes or signs of dislocation, belying a graver injury. As a result of weaker musculature and supporting structures, traumatic forces are transferred more directly and more severely to the neural structures. Fortunately, at younger ages, children have remaining plasticity of bone and neural elements that allow healing potential if treated promptly and appropriately. Thus, the anatomy, injury pattern, radiographic findings, and management of pediatric thoracolumbar spine trauma warrant special consideration.
Among various thoracolumbar spine injuries, a major difference between adults and children is the occurrence of SCIWORA. This pathology occurs almost exclusively in children under 8 years of age due to biomechanical mismatch between the hypermobility of the spine and the lack of tolerance of the spinal cord to stretch to the same degree.
The understanding of thoracolumbar spine injury in children is constantly evolving. In this article, some of the common patterns of injury and their management are reviewed.
Introduction
Pediatric spine trauma is rare, with pediatric patients suffering only 2% to 5% of all spinal injuries. A majority of these are in the cervical spine. This is attributed to the proportionally larger head size in children, in addition to their weaker supportive soft tissue structures in comparison to those of adults. Thus, only an estimated 0.6% to 0.9% of all spinal trauma cases are pediatric thoracic and lumbar spine injuries.
Compared with adult spine trauma, pediatric spine trauma is less likely to result in fracture due to the greater elasticity and compressibility of the pediatric spine. Radiography may show subtler signs, such as splaying of spinous processes or signs of dislocation, belying a graver injury. As a result of weaker musculature and supporting structures, traumatic forces are transferred more directly and more severely to the neural structures. Fortunately, at younger ages, children have remaining plasticity of bone and neural elements that allow healing potential if treated promptly and appropriately. Thus, the anatomy, injury pattern, radiographic findings, and management of pediatric thoracolumbar spine trauma warrant special consideration.
Among various thoracolumbar spine injuries, a major difference between adults and children is the occurrence of SCIWORA. This pathology occurs almost exclusively in children under 8 years of age due to biomechanical mismatch between the hypermobility of the spine and the lack of tolerance of the spinal cord to stretch to the same degree.
The understanding of thoracolumbar spine injury in children is constantly evolving. In this article, some of the common patterns of injury and their management are reviewed.
Pediatric spinal development
Thoracolumbar spine trauma is unique in children due to consideration of the ongoing development of the spine. In the developing child, each vertebra has 3 ossification centers: a centrum and 2 neural arches (ventral and dorsal) that normally fuse between ages 2 and 6 years. Prior to fusion, the centrum and neural arches are connected by a cartilaginous membrane. The neural elements ascend to their normal levels in the spinal canal by the first birthday. By 6 years of age, the spinal canal attains near-adult volume. By 8 to 10 years of age, the spine is generally similar to that of the adult state. Even into early adolescence, however, the pediatric spine has greater mobility due to ligamentous laxity, shallow facet joint angulation, immature paraspinous musculature, and incomplete vertebral ossification.
The developing spine depends on 3 cartilaginous areas for continued vertebral growth: end-plate cartilage, neurocentral cartilage, and the ring apophysis. The end-plate physeal cartilage is adjacent to the bony vertebral body. At birth, the end plate is entirely composed of cartilage; ossification islands appear by 5 years of age in the margins, eventually fusing to form the annular ring apophysis. The ring apophysis, complete by 12 years of age, encircles the full circumference of the vertebral body, providing significant strength. It remains physically separated from the vertebral body by a thin seam of cartilage until 14 to 15 years of age.
Unique features of pediatric spinal anatomy
Unlike that of an adult, the pediatric spine is dynamic; evaluation of injuries should be made in the context of a child’s growth and development. Children have larger heads relative to their bodies and less neck musculature, which predisposes them to flexion and extension-type injuries. In addition, they have inherent ligamentous laxity, elasticity, and incomplete ossification. Children have facet joints that are small and more horizontally oriented, resulting in greater mobility and less stability. As children develop a more adult-like vertebral column between 9 and 16 years of age, they gain sturdier osseoligamentous structures that provided better protection of the spinal cord. Thus, these patients tend to be subject to less severe SCI compared with those in the younger age group. Under high stress, the adult spine is more likely to suffer breakage of bones and frank rupture of ligaments in comparison the pediatric spine, where deformation and return to normal alignment are more common.
Epidemiology
Pediatric spine fractures can occur in the thoracolumbar region, most frequently secondary to high-speed motor vehicle accidents (MVAs) or falls from significant heights. Representing 1% to 3% of all spine fractures, pediatric spine fractures occur in 2 major age groups: those younger than 5 years old and those older than 10 years old. Due to increased activity, there is a seasonal peak during the summer break from June to September and again during winter break. Whereas in younger children less than 10 years old, injuries are most frequently secondary to falls or automobile versus pedestrian accidents (75%), in children 10 to 14 years old, MVAs are more frequent (40%). As they age into late adolescence, motorcycle accidents and sports trauma increase in proportion. The proportion of thoracic and lumbar fractures increases with age, because ligaments stiffen and cervical musculature matures.
Risk factors and prevention
Despite all efforts to optimize treatment of thoracolumbar spine trauma, the most efficacious approach is a public health one—prevention. Because motor vehicle crashes represent a majority of these injuries, prevention strategies targeted to motor vehicle crashes offer the highest yield. Risk factors for SCI include single-vehicle crashes, rollover, and ejection. Before 1959, only 2-point lap belts were available in automobiles. In reality, however, only racecar drivers routinely used seat belts. The 2-point belt strapped across the torso facilitated serious abdominal injuries and thoracolumbar spine fractures in high-speed crashes, especially in small children wearing adult lap belts. Volvo was the first automobile manufacturer to include 3-point belts for front seat passengers as a standard feature. Today, Title 49 of the United States Code, Chapter 301, Motor Vehicle Safety, requires 3-point seat belts in all seating positions. Most seat belt legislation in the United States is left to the states; however, most states (28 states plus the District of Columbia) have enacted mandatory use of seat belts for all passengers. Each of the 50 states and the District of Columbia, however, have enacted their own mandatory child seat belt laws, including regulation of the use of car seats and booster seats.
Types of thoracolumbar spine fractures in pediatrics
Compression Fractures
Compression fractures represent the largest subtype of thoracolumbar fractures in pediatrics. They often occur around the thoracolumbar junction ( Fig. 1 ). The wedge shape of the immature vertebral body and the natural kyphosis make children susceptible to compression fractures. Lower-energy axial loading forces, such as those in minor to moderate falls or sports injuries, are associated with these fractures. Compression of the anterior column in hyperflexion injuries is also a common mechanism, with preservation of the posterior portion of the end plate(s). Multiple levels may occasionally be affected, indicating a higher-energy injury, and should trigger evaluation for intra-abdominal injuries. Most fractures result in less than 30% loss of height; loss of greater than 50% of original height should heighten concern for disruption of the posterior ligamentous complex (PLC) and prompt evaluation by MRI. A large majority of compression fractures do not require surgical intervention. Even in stable injuries, the potential for progressive deformity should be considered when the end plate is damaged and there is significant kyphosis. Fractures with minor loss of height usually recover with conservative management. Thoracolumbosacral orthosis (TLSO) brace therapy can also be considered in nonoperative management of unstable fractures, usually for 6 to 8 weeks, with good results.
Burst Fractures
Burst fractures, similar to compression fractures, occur after axial loading injuries to the thoracolumbar junction ( Fig. 2 ). In contrast to compression fractures, burst fractures are associated with higher-energy trauma, which drives the nucleus pulposus into the vertebral body, leading to fracture of the anterior and middle columns. In younger children, these fractures can also damage the germinal layer, leading to premature epiphyseal fusion. Burst fractures are considered unstable and are more frequently associated with neurologic injury. Retropulsion of fragments of the posterior vertebral body can lead to these injuries and necessitate urgent decompression. CT is the preferred initial modality and can assess compression of canal compromise and extent of bony injury. In addition to this, MRI can provide better visualization of the neural structures, including the spinal cord, conus medullaris, and/or nerve roots that may be affected, as well as the PLC to assess for instability.
Surgical management of burst fractures commonly includes decompression, in addition to stabilization, depending on the presence of a neurologic deficit or canal compromise. The extent of the instrumentation construct is a nuanced decision without clear guidelines. In adults, fusion is typically performed 2 levels above and 2 levels below the fractured vertebral level; however, in children, long fusions may lead to stunted truncal growth and crankshaft deformity. Sparing the developing spine from additional levels of fusion is important from the perspective of growth and in the pursuit of reduced operative morbidity, such as blood loss.
Although percutaneous fixation has been well described in adults, it has yet to be analyzed in great detail and studied in large series in the pediatric population. Alternatives to posterolateral fusion include anterior fusion and lateral fusion (extreme lateral interbody fusion and direct lateral interbody fusion). These are less commonly used in the setting of trauma due to the common need for decompression in addition to arthrodesis. The extent of fusion is also a matter of debate.
Nonsurgical management can be pursued for biomechanically stable fractures without neurologic compromise, usually with a thoracolumbosacral brace (TLSO) for 8 to 12 weeks.
Vertebral Apophysis Fracture
Fracture of the ring apophysis, also called slipped vertebral apophysis injury, can occur in children, most commonly at L4 or L5 ( Fig. 3 ). Clinical presentation is most commonly back pain and radicular leg pain, similar to those of disk protrusion in adults, but can also include neurogenic claudication. These fractures are a distinct entity that warrants awareness in children. CT is the best diagnostic imaging for this. A standard approach for discectomy with fragment removal may not be necessary and may increase surgical risk; posterior laminar decompression alone at the involved levels may relieve presenting symptoms and allow for good functional outcome. Overweight children may be at additional risk of this pathology.
Seat Belt Injury
Seat belt injuries are a specific type of flexion-distraction injury frequently associated with severe abdominal trauma ( Fig. 4 ). Classically, this includes a small bowel mesenteric tear or perforation and a compression or chance-type fracture. The rib cage protects the thoracic spine against horizontal displacement but provides little protection against longitudinal distraction that can occur in these injuries. The mechanism involves migration of the lap belt toward the anterior abdominal wall, due to the tendency of children to sit further over the edge of the seat. Sudden deceleration then results in direct compression of viscera occurring between the seat belt and the spine, with the flexion fulcrum placed at the anterior vertebral body. In pediatric patients, the most commonly affected levels are L2 and L3 compared with the thoracolumbar junction in adults. Further contributing to the likelihood of neurologic injury is that the elasticity of the pediatric spinal column far exceeds that of the spinal cord and the dura. In their review of 28 children with seat belt syndrome, Santschi and colleagues found 43% had a spinal cord injury, associated with a wide spectrum of fractures beyond the classic chance fracture. Thus, patients with this pattern of injury require special consideration, including a comprehensive trauma survey, because 50% of patients also present with significant abdominal injury (ie, the nutcracker phenomenon, where the head of the pancreas, third segment of the duodenum, and left renal vein are crushed between the superior mesenteric artery and aorta).
Slow Vehicle Crushing Injury
Slow vehicle crushing injuries, also referred to as driveway injuries, most often affect the thoracic spine and are seen in children under 5 years of age. These occur most often when drivers back out slowly from a parking space, not noticing a child in the vicinity. Injury can occur when a patient’s thoracic spine is upright and pinned between the car bumper and another surface, resulting in hyperextension and associated thoracoabdominal injures. Other, often younger, patients are run over by a car tire at low speeds, indicated by tire marks across the chest or abdomen, indicating potentially major thoracic or intraperitoneal injuries. Spinal injuries are most common in the former due to the presence of spinal hyperextension.
Traumatic Spondylolisthesis/Spondylolysis
Traumatic spondylolisthesis/spondylolysis of the thoracic and lumbar spine can occur in several ways, some which merit special mention in the pediatric population ( Fig. 5 ). In the typical nomenclature of 6 types of spondylolisthesis, type IV is designated for traumatic spondylolisthesis without injury to the pars (usually from a fracture dislocation), whereas type II indicates spondylolysis. Type II spondylolisthesis is further broken down into 3 subtypes. Type IIA occurs in younger children with congenital abnormality of the lumbosacral spine, such as spina bifida occulta or variation in number of lumbosacral vertebra, predisposing them to pars articularis (pars) fatigue and microfractures. Type IIB is similar but with partial healing of the microfractures resulting in abnormally elongated pars. Type IIC, a rare type, results from high-velocity injuries that cause isolated pars fracture and resultant slip.
Related posts:
Update on New Imaging Techniques for Trauma
Thoracolumbar Trauma Classification
Classification and Management of Pediatric Craniocervical Injuries
Classification and Management of Pediatric Subaxial Cervical Spine Injuries
Treatment of Odontoid Fractures in the Aging Population
Complications in the Management of Patients with Spine Trauma
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
