Spine Trauma in Children

Michael G. Vitale, MD, MPH

Richard C. E. Anderson, MD

Douglas L. Brockmeyer, MD¹

Mark A. Erickson, MD, MMM¹

¹Gurus:

General Principles in Pediatric Spine Trauma

Significant pediatric spine trauma is fortunately rare but carries with it the possibility of significant trouble. Given the obvious challenges in obtaining a clear history and examination, and issues with imaging, diagnosis of these injuries can be difficult. Have a very high index for suspicion of a spine injury when presented with a child with multiple injuries or high-energy trauma.

It is helpful to understand a bit about the developmental anatomy and biomechanics of the growing spine as these injuries often follow specific patterns related to age and location.

Until around 8 or 9 years of age, the maturing spine is much more malleable resulting in specific injury patterns; after this age, the biomechanics approach those of adults, as do injury patterns.¹,²,³

The main biomechanical difference between the pediatric and adult spine is that the developing spine is less ossified and more elastic. The child’s spine is an able to undergo considerable movement between vertebral segments without damage, but at the cost of providing less protection to the underlying spinal cord.

For example, about half of all spine injuries in children involve the cervical spine, with the level of injury moving more caudal with progressive age. However, fractures of the cervical spine (as opposed to ligamentous injuries, subluxation, etc.) are less common until children are older than 13 years. To stay out of trouble, both fractures and ligamentous injuries must be ruled out prior to cervical spine clearance in young children. Similarly, thoracolumbar injuries are less common until adolescence.

It is also important to be aware that children very commonly sustain injuries at multiple levels of the spine (either contiguous or not), so it is important to carefully survey the entire spinal column in children. Don’t be satisfied with the identification of a single abnormality; our job is to make sure the entire spine is clear. Finally, in younger children without an obvious history of high-energy trauma such as a fall or motor vehicle accident (MVA), it’s important to rule out nonaccidental injury (child abuse) or pathological fracture.⁴

Given the plasticity of the child’s spine, younger children can sustain pure ligamentous injuries without bony fracture. SCIWORA (spinal cord injury without radiographic abnormality) is a rare injury where there is subluxation or distraction of the spinal column, which then bounces back to its anatomical position “without radiographic abnormality.”⁵

Strictly speaking, SCIWORA really means that there are no changes on MRI, but MRI in these cases often reveals disruption of the posterior ligaments and/or increased signal in the spinal cord. It is surprisingly common for SCIWORA to present up to 24 hours after the injury, so repeated neurological examinations are wise in a child with significant trauma, such as an MVA. Children with neurological injury in the cervical or thoracic spine can rapidly develop scoliosis (Fig. 11-1).

Evaluation of Children With Suspected Spine Injuries

The initial history and physical examination is critical. Learn as much detail as possible about the mechanism of injury, and search for signs of head injury or skin findings such as a lap belt sign across the abdomen. Remember that the disproportionately large head of young children will put them in a position of relative flexion/kyphosis if immobilized flat. The torso therefore needs to be bolstered if a cervical spine injury is suspected (Fig. 11-2). Similarly, a cervical collar can be
too large for young patients resulting in dangerous distraction forces. A history of loss of consciousness or facial or skull or even clavicle injury should raise concern about a possible cervical spine injury. In about 40% of children with cervical spine injuries, additional orthopaedic injuries are reported. Once any spine injury is noted, imaging and physical examination of the entire spine must carefully be assessed for other distant spine injuries, which are not uncommon. The isolated spine fracture should really be a diagnosis of exclusion.

Figure 11-1 A 3-year-old boy presented after being struck by a car as a pedestrian. A: He had sustained multiple injuries, including head trauma, epidural hematoma, bilateral pneumothoraces with right lung contusion, multiple right rib fractures, ruptured bladder, pelvic fracture, and right femoral fracture. B: X-rays show no evidence spinal injury. Eight months later, the patient developed severe scoliosis (C), which was treated with vertical expandable prosthetic titanium rib (VEPTR) (D).

If there is a potential spinal cord injury (SCI), document a thorough neurologic examination. Spinal shock results in loss of the bulbocavernosus reflex which almost always returns within 24 hours after injury. Complete injuries are defined by the absence of motor and sensory function below the level of SCI after the resolution of spinal shock. Sacral sparing, the presence of perianal sensation, rectal motor function, and/or great toe flexor function indicates a good prognosis for neurologic recovery.

Figure 11-2 A: The relatively large head of the child forces the injured spine into flexion and can be a problem. B: Children need a modified backboard to hold their cervical spine in neutral.

Cervical spine X-rays are a part of most initial trauma evaluations. If these initial films are normal, but the child has neck pain, tenderness, about the spine, or concern of injury and is awake and cooperative, flexion/extension lateral cervical spine radiographs should be the next step. To stay out of trouble, clinicians should remember that ligamentous injury is more common than osseous injury in children and cannot be excluded based on normal bony anatomy demonstrated on static radiographs or CT scans. Don’t be fooled by certain, classic false positives in children. These include retropharyngeal “swelling” due to crying and C2-3 pseudosubluxation (Fig. 11-3). Advanced imaging, including CT and MRI, is often necessary to better assess suspected spine injury in children. MRI has shown to be an effective method for clearing the cervical spine in obtunded children. As the sensitivity of MRI to detect edema associated with ligamentous injury is reduced after 48 hours from spinal column trauma, the study should be obtained within this time interval in order to be diagnostic.⁶ So the bottom line is if in doubt, MRI the spine early.

While there is no consensus on which particular protocol is best, the use of defined protocols decreases the time needed to clear the cervical spine in children, reduces the number of missed injuries, and facilitates clearance by nonneurosurgical medical staff.⁷,⁸,⁹,¹⁰,¹¹ Figure 11-4 is a useful algorithm recently developed by a multidisciplinary group that stratifies by GCS rather than age or mechanism of injury.

Figure 11-3 Pseudosubluxation of C2/C3. A: Pathological subluxation of C2/C3 with more than 1.5 mm step-off of the spinolaminar line (Swischuk line) drawn from spinolaminar point on C1 to C3. The spinolaminar point on C2 should be within 1.5 mm of the spinolaminar line. B: Pathological pseudosubluxation of C2/C3 with no significant stepoff at posterior line. Around 20% of children admitted for polytrauma will demonstrate this incidental finding, most commonly seen at C2/C3 and in children younger than 8 years. (Used with permission of the Children’s Orthopaedic Center, Los Angeles.)

Figure 11-4 Pediatric cervical spine clearance working group algorithm. (Reprinted with permission from Herman MJ, Brown KO, Sponseller PD, et al. Pediatric cervical spine clearance: A Consensus Statement and Algorithm from the Pediatric Cervical Spine Clearance Working Group. J Bone Joint Surg Am. 2019;101(2):e1. Copyright © 2019 by The Journal of Bone and Joint Surgery, Incorporated.)

Traumatic Injuries of the Cervical Spine

ATLANTO-OCCIPITAL DISLOCATION

Atlanto-occipital dislocation (AOD) involves traumatic separation of the occiput from C1 and is an injury that occurs much more frequently in the pediatric population, due to the laxity of the ligamentous structures anchoring the occiput to the axial skeleton. Resulting from high-energy deceleration such as occurs in pedestrian MVAs, these injuries in children are often lethal. The dislocation usually severs the spinal cord at the foramen magnum, resulting in acute respiratory arrest¹² (Fig. 11-5).

To stay out of trouble, understand that these injuries may often not be appreciated on the initial presentation of the child to the trauma center. Some of these injuries reduce in the field or on transport to the trauma facility and then are not discovered until radiographs are done in a different position, especially traction. It is important to keep in mind that most survivors of AOD, including those with a severe initial presentation such a flaccid quadriplegia, have incomplete injuries and ultimately may have a good outcome. Radiographic findings on plain films may be subtle and AOD should be suspected in any child involved in a high-speed trauma, especially those presenting with cardiopulmonary instability and associated facial injuries. Maintain a high index of suspicion and obtain a thin-cut CT imaging from the occiput to at least C2 with sagittal and coronal reconstructions. The most accurate way to diagnose AOD is by measuring the condyle-C1 joint interval (CCI) on CT.¹³ A CCI of greater than 4 mm in either the sagittal or coronal plane for one or both O-Cl joints is considered a positive finding (Fig. 11-6). AOD is exceedingly unstable so prompt external immobilization is critical. Stay out of trouble by remembering that cervical traction is contraindicated after AOD as it may result in additional cervicomedullary injury. Given that AOD is extremely unstable and there is a very real risk of further neurological injury with inadequate immobilization, internal fixation and fusion from O-C2 is typically performed.

C-1 INJURIES (JEFFERSON FRACTURE)

These injuries present some challenges in diagnosis. It is important to distinguish a Jefferson fracture (Fig. 11-7) from an unfused synchondrosis, which is generally

not of any clinical significance. Alternatively, C1 fractures may occur through the synchondrosis and can be missed on plain radiographs. Atlas fractures may be accompanied by disruption of the transverse ligament, resulting in atlantoaxial instability. There is a high incidence of associated C2 fracture. CT imaging has led to an increased recognition of these fractures children14 (Fig. 11-8). On odontoid view radiographs, transverse ligament disruption is suggested if the sum of the total overhang of the C1 lateral masses on C2 is 7 mm or more (the “rule of Spence”). Treatment of isolated Jefferson fractures with an intact transverse ligament is generally external immobilization in a rigid cervical collar, Minerva brace, or halo. If there is transverse ligament rupture and atlantoaxial instability, treatment should involve either halo immobilization or, rarely, C1-2 internal stabilization and fusion.

Figure 11-5 A: CT of a 1-year-old struck by a car demonstrating occiput-C1 dislocation. B: MRI demonstrates transection of the spinal cord. (Used with permission of the Children’s Orthopaedic Center, Los Angeles.)

Figure 11-6 A: A 10-year-old boy pedestrian hit by a car presented with GCS 8 and imaging consistent with atlanto-occipital dislocation (AOD). B: Coronal CT demonstrates increased condylar-C1 interval (CCI) bilaterally and sagittal short-TI inversion recovery (STIR) MRI demonstrate ligamentous injury with clival hematoma. C: Postoperative lateral radiograph after occipital-C2 stabilization using rigid internal fixation and iliac crest structural allograft with cable.

Figure 11-7 This 14-year-old boy had neck pain after colliding with a tree while snowboarding. A, B: Sagittal and axial CTs show multiple C1 fractures with displacement. MRI (not shown) demonstrated ligamentous injury. C, D: Postoperative AP and lateral radiographs after bilateral C1 lateral mass fixation, C2 pars screws, and iliac crest allograft with wire.

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