A 3-year-old child is playing with some older children on a backyard trampoline when he falls from the trampoline and strikes his head on the support. He experiences a transient loss of consciousness and a minor laceration just below the mandible on the right side. His older brother helps him up and he is able to walk inside. He is brought by his mother to the ED for evaluation. In the ED, he is alert, crying and resists examination. He has a small right submandibular laceration which does not require suturing and a right parietal contusion. The rest of the physical examination, including the neurological, is normal. He is discharged to the care of his mother who is given routine head injury instructions.
Twenty-four hours later, the child is brought back to the ED by the mother who has noted that he will not move his neck. She states that he cries and says that his neck hurts when he moves it. On examination, he is rigidly holding his neck in neutral position and is tender to palpation of the upper cervical spine area. His neurological examination remains intact. He is immobilized on a long spine board and cervical spine radiographs are obtained. A fracture of the second cervical vertebra is diagnosed and the child is transferred to a pediatric trauma center for neurosurgical evaluation.
PEDIATRIC CERVICAL SPINE INJURY
Background, Risk Factors and Epidemiology
Cervical spine injury (CSI) in the pediatric patient is relatively rare but of great diagnostic importance to the emergency physician since CSI can result in catastrophic sequelae.
The overall incidence of CSI for all ages in the United States is roughly 10,000 cases per year. Of these, 10% are in the pediatric age group. Half of these are in adolescents or children over the age of 8 years, where the diagnostic and management issues are essentially the same as they are in adults. This leaves about 500 cases of CSI per year that occur in infants or children under the age of 8 years. The Children's National Medical Center has reported a bi-modal distribution of pediatric CSI, with peak incidences between 2 and 4 years of age (toddler exploring behavior) and between 12 and 15 years of age (adolescent risk-taking). Unlike in adolescents and adults where 80% of cases occur in males, the male - female distribution in younger children is close to 50:50.
The most common etiologic factor in all age groups is the motor vehicle crash (MVC), which accounts of 40% of pediatric CSI and for 80% of the deaths. Falls and sports injuries are the next most common etiologies, responsible for about 20% each.
The cervical spine
consists of 7 cervical vertebrae and the ligamentous structures which
support them and maintain alignment. The 1st and 2nd cervical vertebrae,
the atlas and axis, are specialized structures with adaptations for load-bearing
and marked rotation. In the pediatric cervical spine, there are ossification
centers and synchondroses that increase the complexity of x-ray diagnosis.
Ligamentous laxity and hypermobility of spinal structures also give rise
to findings not commonly seen in adults.
Anterior psuedosubluxation of C2 on C3 is seen in almost half of children x-rayed and is most marked under the age of 8 years. It is accentuated in flexion. Differentiating anterior pseudosubluxation from an occult Hangman's fracture can be accomplished with the use of the posterior cervical line (PCL). The PCL connects the bases of the spinous processes of C1, C2 and C3. If the PCL misses the anterior aspect of the spinous process of C2 by 2 mm or more, a true subluxation is indicated.
Posterior pseudosubluxation may also be present with extension. Pseudosubluxation of C3 on C4 is less common but not unusual.
Other effects of hypermobility of the pediatric cervical spine are widening of the atlanto-dens interval, which is normally < 3 mm, and over-riding of the anterior arch of C1 on the odontoid with extension. Absence of uniform angulation between the vertebrae, simulating ligamentous disruption, is frequently seen in the neutral position or with flexion, but is reduced with extension. Absence of lordosis in the neutral position, simulating muscle spasm, may also be seen.
Another factor that complicates the interpretation of pediatric cervical spine films is the progressive maturation of the vertebral bodies. In infancy, the vertebral body is oval-shaped. As the child gets older, this progresses to an anterior wedge shape which is present throughout the rest of childhood. This shape can simulate a wedge compression fracture. However, in the normal pediatric cervical spine, there should be < 3 mm difference in the height of the anterior and posterior aspects of the vertebral body.
The pre-vertebral soft tissue space may appear wide even in the presence of a normal cervical spine, especially when the film is shot in exhalation or in flexion. This space is considered abnormal only when it exceeds ¾ of the anteroposterior width of the adjacent vertebra, about 7 mm at C2-C3.
The interspinous space between C1 and C2 may also appear widened, suggesting disruption of the posterior elements, as in a hyperflexion sprain. It is considered abnormal only if it is > 10 mm.
Cervical spine injury should be considered in all children sustaining multiple trauma, falls from heights and in those involved in MVCs. In addition, CSI should be considered when there is significant localized trauma to the head or neck.
will usually complain of pain localized to the site of injury, while younger,
less verbal infants and children will simply cry, especially with attempts
to move the head or neck. Altered mental status or distracting injuries
may make detection of CSI even more difficult.
Most children with CSI will have a normal neurological examination, but motor, sensory and reflex abnormalities may be seen with more severe injuries. Transient paresthesias (pins and needles, electric shock, numbness or burning) may be seen at the time of injury and may promptly resolve. Nevertheless, such symptoms may be indicators of CSI.
Analysis of the National Pediatric Data Registry over a 10-year period, revealed an overall incidence of CSI of 1.5% of injured children. The mean age of those with CSI was 11 years and boys constituted 61% of the cases. Eighty-three percent had bony injury, with 52% involving the upper cervical vertebrae, 28 % the lower cervical vertebrae and 7% involving both. Upper cervical spine injuries were found to occur with relative frequency in both younger children (8 years or less) and in older children (more than 8 years). Lower CSI was seen predominantly in older children. The mortality rate for upper cervical injury was found to be 23%, compared to 4% for lower cervical injury.
One third of children had neurological injury, 76% incomplete and 24% complete. Half of those with neurological injury had no radiographic evidence of injury (SCIWORA).
Complete cord syndrome is characterized by the absence of all motor and sensory function below the level of injury. Pain at the site of injury is maintained. There is no autonomic function below the level of injury, giving rise to loss of sweating and vasomotor control and in some cases to priapism. A moderate degree of hypotension may be associated. The bulbocavernosus reflex is preserved in all but the most severe complete cord syndromes and its absence carries a grave prognosis. It is elicited by placing a finger into the rectum and then squeezing the glans penis or the clitoris while observing for reflex contracture of the anal sphincter.
Incomplete cord syndromes typically consist of either central, anterior or unilateral (Brown-Sequard) cord syndromes. Central cord syndrome is typically associated with a hyperextension mechanism of injury which results in impingement of the ligamentum flavum on the cord. The neurological deficit is more severe in the upper extremities than in the lower extremities due to the way the motor fibers are laid out in the pyramidal tracks. The Brown-Sequard syndrome is characterized by ipsilateral absence of motor and proprioceptive function along with contralateral loss of pain and temperature sensation. It is due to unilateral injury, typically by penetrating trauma or by unilateral facet dislocation. Anterior cord syndrome is characterized by a complete loss of motor function below the level of injury, along with loss of pain and temperature sensation, but with preservation of position and vibration senses. It is frequently due to impingement of bone fragments on the anterior aspect of the cord and may be amenable to early surgical intervention.
Spinal cord injury without radiographic abnormality (SCIWORA) is due to non-disruptive, self-reducing, intersegmental deformation that may be associated with variable mechanisms of injury in the child with hypermobility of the cervical spine. In the National Pediatric Trauma Registry review, SCIWORA made up 17% of the cases of CSI. Patients who go on to develop SCIWORA may have transient symptoms that have resolved before presentation. Nevertheless, they may have a delayed deterioration that can be severe.
The most common types of vertebral fractures seen in the pediatric age group involve the upper cervical vertebrae. Fracture or subchondral separation of the odontoid is one of the most common. It is thought to be caused by major anterior displacement of the upper cervical spine, resulting in shearing forces applied to the odontoid. In the setting of MVCs, it can occur when infants are secured in forward-facing car seats. Odontoid fracture is frequently not associated with any neurological injury due to the ample space for displacement within the ring of the atlas (C1) without impingement on the cervical cord.
The Hangman's fracture is a fracture-subluxation involving the posterior elements of the axis (C2). There is bony disruption through the pedicles with anterior displacement of the body and posterior displacement of the laminae and spinous process. The usual mechanism is hyperextension and distraction. Again, the Hangman's fracture is frequently not associated with neurological injury due to the ample space about the cord at the level of C2 and due to the auto-decompression inherent in the injury.
Atlanto-axial rotatory subluxation results from disruption of the transverse ligament, the function of which is to keep the odontoid in place in close proximity to the anterior arch of the atlas (C1).
The Jefferson fracture occurs when there is disruption of the ring of the atlas (C1), classically in more that one location about the ring. It may be very hard to detect when the disruption is at the site of ossification centers. The mechanism of injury is vertical loading, such as with a fall onto the top of the head. It is frequently associated with no neurological deficit.
Atlantooccipital dislocation results from disruptions of the musculature, apical ligament, atlantooccipital joints, and tectorial membrane and is frequently associated with high cord injury. The mortality rate is almost 50%, but some patients, especially those without tectorial membrane disruption can have no neurological abnormality. An interspinous C1-C2:C2-C3 ratio of > 2.5 is predictive of tectorial membrane abnormalities. The atlanto-occipital interval should not be > 5 mm.
Physeal injuries may occur at any level of the cervical cord and may occur in adolescents and young adults. The superior and inferior epiphyseal rings are present up to about age 25 years.
Laboratory studies are not specifically helpful in the evaluation of CSI and are indicated only as needed for the evaluation of associated illness or injury.
The standard 3-view cervical spine series has traditionally been used for radiological screening for evidence of CSI. It consists of anteroposterior, lateral and open-mouth odontoid views. The odontoid view is difficult to obtain in young children and efforts to obtain it can result in delays in treatment or further damage to the child. In a retrospective, multiinstitutional review of 51 children with CSI, Buhs, et. al. found that the transoral odontoid view was not used to make the diagnosis of CSI in any patients. The American Society of Neurological Surgeons now recommends only anteroposterior and lateral views for the radiological evaluation of children 8 years of age or less. The odontoid view is still recommended for older children.
Oblique views are unlikely to be abnormal if no acute abnormalities are evident on standard anteroposterior and lateral radiographs. Their use is not recommended as part of the routine radiographic evaluation of acute cervical trauma.
radiographs may be helpful in revealing ligamentous instability when standard
views show suspicious findings. They are unlikely to be abnormal when
no abnormality or only loss of normal lordosis is noted on the standard
Magnetic resonance imaging (MRI) is valuable in the evaluation of potential CSI, especially in obtunded children, in those with equivocal radiographs, and whenever the cervical spine cannot be cleared by traditional means. MRI is also recommended for evaluation of children with neurological symptoms without radiographic findings.
The first challenge encountered in the management of potential CSI is immobilization of the cervical spine. Due to the relatively large head of the child, immobilization of a child under the age of 8 years on a flat backboard will force the child's head into flexion. The use of a properly fitted semi-rigid collar will reduce the flexion but will not eliminate it. Proper immobilization of the child under the age of 8 years requires either the use of a special board with a recessed area for the occiput or the placement of a double mattress pad under the chest and back.
Children with potential CSI may require circulatory support due to coexistent injury or may exhibit evidence of neurogenic shock due to loss of sympathetic cardiovascular tone. Regardless of the cause, fluid resuscitation should be instituted immediately, either by intravenous or intraossesous routes. When the cause is neurogenic shock, the blood pressure is usually only moderately low. Continued administration of large volumes of fluid is not likely to be helpful and may result in edema that is detrimental to the damaged cord. Pressors with a-adrenergic effects, such as high-dose dopamine and phenylephrine, may be useful in reversing the effects of loss of sympathetic tone. Bradycardia may be an associated finding and atropine can be used if it is needed.
The National Acute Spinal Cord Injury Study, published in 1990, found a beneficial effect of the use of high-dose steroids in the setting of spinal cord injury. The presumed mechanism of action is inhibition of lipid peroxidation and hydrolysis in the injured cord. Methylprednisolone is recommended in a dose of 30 mg/kg over 15 minutes, followed by an infusion of 5.4 mg/kg per hour for 23 hours. There were no children under the age of 12 years in the study population used to substantiate this recommendation. However, most authorities continue to recommend the use of high-dose steroids for children with spinal cord injury, regardless of age.
Pediatric patients constituted 3065 (9%) of all NEXUS study patients and 30 (0.98%) had CSI. Only 4 of the 30 children with CSI were younger than 9 years and none were younger than 2 years. The NEXUS decision instrument correctly identified all pediatric CSI victims in this study. Its use could reduce pediatric cervical spine imaging by nearly 20%. Due to the lack of infants and toddlers in the study population, caution in applying the decision rule in this age group is advised.
The use of the
NEXUS criteria for evaluation of pediatric trauma patients is recommended
by the American Society for Neurological Surgeons.
Diagnosis: Fracture though the pedicles of the axis (C2) with traumatic subluxation, the Hangman's fracture. No associated neurological impairment.
The patient was immobilized using a semi-rigid cervical collar and a long spine board. A double mattress pad was placed under the child's back and shoulders to avoid forcing the neck into flexion during immobilization.
Lateral and anteroposterior radiographs were obtained which demonstrated the fracture as outlined above.
The patient remained
stable and transfer to a pediatric trauma center was arranged.
1. Congress of Neurological Surgeons: Management of pediatric cervical spine and spinal cord injuries. Neurosurgery 50(3 Suppl):S85-99, 2002.
1. Proper immobilization
of the cervical spine of a child less than 8 years of age can be achieved
using which of the following techniques?
to the NEXUS criteria, all the following are supportive of the decision
to x-ray the neck of an injured child EXCEPT:
3. Which of
the following series of radiographs is recommended for the evaluation
of the cervical spine of a child less than 8 years of age?
4. Which of
the following is true regarding vertebral fractures in children?
of the pediatric cervical spine may be responsible for all the following
radiographic findings EXCEPT?
1. Answer d.
2. Answer c.
3. Answer a.
4. Answer a.
5. Answer c.
Slide 6, 34: American College of Emergency Physicians, American Academy of Pediatrics: Advanced Pediatric Life Support Course, 1999.
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Slides 17, 28: Strange GR, Ahrens WR, Lelyveld S, Schafermeyer RW: Pediatric Emergency Medicine: A comprehensive study guide, 2nd Edition. New York: McGraw-Hill, 2002.
Slides 18-22: Fielding JW: Cervical spine injuries in children. Jn: The Cervical Spine Research Society (eds): The Cervical Spine. Philadelphia: JB Cippincott; 1983:268-81.
Slides 24-29: Catell HS, Filtzer DL: Pseudosubluxation and other normal variations in the cervical spine in children: A study of 160 children. J Bone Joint Surg 47A:1295-1309, 1965.
Slide 33: Fleisher GR, Ludwig S, et al (eds): Textbook of Pediatric Emergency Medicine, 3rd Edition. Baltimore: Williams and Wilkins, 1993.
Slides 35, 38: Swischuk LE: Anterior displacement of C2 in children: Physiologic or pathologic? Radiology 122:759-763, 1977.
Slide 37: Woods WA: Pediatric cervical spine injuries: Avoiding potential disaster. Trauma Rep 4(4):1-12, 2003.