The cervical spine consists of the upper spinal cord, surrounded by seven vertebrae and their ligaments. Injuries to this area can involve any one or all of these structures, but those with the most serious long-term sequelae involve the spinal cord. Movement of patients with unstable cervical spine injuries may result in spinal cord damage by blood or bony fragments. Stable injuries are unlikely to have subsequent impairment of the spinal cord.
The incidence of cervical spine injuries among US children is about 18 per million per year.1 Approximately 1300 cervical spine injuries occur in the United States annually. More than 80% of these occur in children older than 10 years. Boys are more likely to be injured than girls. The most common mechanism of injury is blunt trauma from motor vehicle collisions, falls, and sports-related accidents, each of which account for about 30% of significant cervical spine trauma. The sports most commonly involved are diving, football, gymnastics, and hockey.2 Because participation in football is about 20 times that of the other three sports, most of the sports-related cervical spine injuries occur in football. Children with Down syndrome, Klippel-Feil syndrome, and mucopolysaccharidoses are at increased risk of cervical spine injury because of ltgamentous laxity and bony abnormalities of the upper cervical spine. The incidence of penetrating cervical spine injuries, particularly bullet and stab wounds, has more than doubled in the last decade.3
CLINICAL PRESENTATION AND TYPES OF INJURIES
Symptoms that may indicate a cervical spine injury are neck pain, paresthesias, fecal or urinary retention, weakness, and inability to move the neck. A careful and complete neurologic examination is the most important and sensitive test in cervical spine trauma. Some specific signs are an abnormal motor or sensory examination, neck muscle spasm, neurogenic shock (bradycardia, hypothermia, and hypotension), priapism, ileus, temperature instability, diaphragmatic breathing, abnormal reflexes, Homer's syndrome (unilateral ptosis, miosis, enophthalmus, and loss of facial sweating), and clonus without rigidity.4'8 Any new neurologic abnormality in a child with a history of trauma should arouse suspicion for a cervical spine injury. Neurologic abnormalities occasionally may not be manifest for up to 24 hours, so serial examinations in trauma suspicious for cervical spine injury are necessary.
Figure 1. A line drawing (left) and an open-mouth radiograph (right) of a fracture of the odontoid process.
Among all pediatrie cervical spine injuries, about 60% involve a fracture without a neurologic deficit, 20% involve both fractures and spinal cord injury, and 20% only involve the spinal cord.4-11 In adults, 85% of cervical spine injuries occur below the level of C-3, whereas among children younger than 8 years, only 30% are lower cervical spine injuries. This difference has been attributed to the anatomic and biomechanical differences between children and adults. The fulcrum of the spine is at C-2 and C- 3 in children, compared with the lower cervical spine in adults.
The largest series of pediatrie cervical spine injuries lists the most common diagnoses as:
* spinal cord injury without radiographie abnormality (SCIWORA),
* atlantoaxial rotary fixation,
* fracture of a spinous process (clay shoveler's fracture),
* fracture of a transverse process,
* fracture of the odontoid process,
* dislocation of two adjacent vertebrae with locked facets,
* compression fracture of a vertebral body, and
* burst fracture of C-I (Jefferson fracture).4,7,10,11
The four most common and serious of these will be discussed in greater detail, while information about the others can be found in current references.12
Spinal Cord Injury Without Radiographic Abnormality
Spinal cord injury without radiographic abnormality probably occurs when the spinal cord is stretched, torn, or contused during trauma with transient displacement of the vertebrae, that subsequently realign in a normal configuration. A stable cervical spine injury, SCIWORA occurs in children because of the ligamentous laxity and multiple ossification centers of the developing spine." Spinal cord injury without radiographie abnormality accounts for about 15% to 25% of all pediatrie cervical spine injuries and can present with partial neurologic deficits (incomplete lesion} or flaccid paralysis as is seen in a spinal cord transection (complete lesion).14 Spinal cord injury without radiographie abnormality is more common in younger children (<8 years), presenting as a complete lesion 75% of the time. The prognosis for neurologic recovery in SCIWORA with a complete lesion is extremely poor. Spinal cord injury without radiographie abnormality is sometimes a result of child abuse; the violent shaking of a young child with a relatively large head can result in hemorrhages in and around the cervical spinal cord without fractures. The term SCIWORA was coined before magnetic resonance imaging (MRI) was available. When patients with SCIWORA have been studied by MRI, most show abnormalities of the spinal cord. The lesion most frequently seen is a swollen spinal cord with occlusion of the subarachnoid space.15
Fracture of the Odontoid Process
The odontoid process is predisposed to an avulsion fracture in younger children because of its incomplete ossification (Figure I).16 The mechanism of injury is often a fall. These children complain of neck pain and hold their heads and necks rigid, sometimes with a head tilt. Seventy-five percent present with minimal associated neurologic deficits because the spinal canal is larger at the C-I level than more caudally, allowing for displacement without compromise of the spinal cord. Nonetheless, this is an unstable fracture. Widening of the predentai space may be seen on the lateral cervical spine radiograph or the odontoid process may be obscured by the arches of C-I. An open-mouth plain radiograph or a computerized tomograph (CT) scan may be required to visualize the odontoid process.
Dislocation of Two Adjacent Vertebrae With Locked Facets
Dislocation of two adjacent vertebrae with locked facets is an injury seen in older children after hyperflexion injury, such as a diving accident (Figure 2). The posterior ligaments are disrupted bilaterally, and both facets are dislocated. Neurologic involvement is common, and complete cord transection (flaccid areflexia and complete sensory loss below level of injury) often occurs. A unilateral facet dislocation can present with a hemicord transection (Brown-Sequard syndrome, ipsilateral loss of proprioception and motor function, and contralateral loss of sensation below the level of the lesion). The body of the upper vertebra will appear 50% anteriorly translocated on lower vertebra on a lateral cervical spine radiograph. This is a highly unstable fracture.
Atlantoaxial Rotary Fixation
Atlantoaxial rotary fixation (rotary subluxation) is unilateral rotary dislocation of the facet of C-I on C2.17 There is typically a history of minor trauma, cervical adenitis, or recent general anesthesia. Children may complain of neck pain and hold their heads laterally flexed with the chin rotated to the contralateral side ("cock-robin deformity"). The neurologic examination is usually normal, but signs of a C-2 radiculopathy (occipital pain, loss of occipital sensation, weakness of the muscles of breathing or upper extremities, and upper torso paresthesias) may be seen. This injury is more common in children with Down syndrome and mucopolysacchartdoses. Twentyfour percent of children with Down syndrome will have radiographic atlantoaxial instability, and 1 % are symptomatic from this problem. This instability is progressive, so as the child matures, he or she may develop new or worsening instability. This stable lesion is treated with closed reduction and traction by a neurosurgeon. The prognosis is good.
Figure 2. A line drawing (top) and a lateral neck radiograph (bottom) of dislocated vertebrae with locked facets.
Klippel-Feil syndrome is characterized by a short neck and atlanto-occipital fusion. These patients may present with neck pain and myelopathy without trauma secondary to spinal cord compression. Minor trauma may result in a fracture of the fused C-I to C-2 bone and catastrophic spinal cord injury.
Figure 3. Infant immobilization (left) and child immobilization (right). (Infant diagram reprinted with permission from Strange GR, Anrens WR1 Lelyveld S, Schafermeyer RW, eds. Pediatrie Emergency Medicine. Copyright ©1996, McGraw Hill.)
INITIAL MANAGEMENT AND PROGNOSIS
The primary goal of initial trauma management is to restore and maintain adequate oxygenation and perfusion, while at the same time stabilizing the cervical spine to avoid causing further spinal cord injury. This approach has been standardized by Pediatrie Advanced Life Support (PALS) and Advanced Trauma Life Support (ATLS) protocols. Maintaining adequate oxygenation and perfusion limits further hypoxic- ischemic insults to the spinal cord. These protocols facilitate safe transfer to a trauma center. While the possibility of an unstable cervical spine injury should never make the practitioner reluctant to resuscitate a patient, it does necessitate precautionary measures until a more thorough evaluation can be done. Backboards should be moved under the injured children, rather than moving the injured children onto backboards. If the back of the child is being visualized, the child should be "log-rolled" (rolled in concert by two medical personnel with one holding the head and neck immobilized in line). Efforts to open the airway should use the chin lift or jaw thrust maneuvers, avoiding neck extension. If an endotracheal tube is required to maintain an open airway, the ATLS protocol recommends intubation by directly visualizing the trachea with the neck firmly held in the neutral position by manual stabilization.
Immobilization of the spine is indicated whenever there is post-traumatic neck or upper back pain, posttraumatic shock or neurologic abnormalities, or posttraumatic impaired level of consciousness. A mechanism of injury compatible with serious cervical spine injury, such as a passenger in a high-speed motor vehicle accident, a pedestrian hit by a vehicle, penetrating trauma to the upper back or neck, or an upper body or head injury during football, diving, gymnastics, or hockey, is also an indication for immobilization. Children with a mechanism of injury compatible with serious cervical spine injury who are intoxicated, preverbal, or have other very painful injuries that may distract them from their neck pain also should be immobilized.
Immobilization of the child's cervical spine is best achieved by securing the child to a hard backboard (Figure 3). A pad, about one-inch thick, placed under the child's shoulders is recommended to bring the cervical spine into a neutral position18; otherwise, the prominent occiput results in neck flexion on a flat surface. The forehead and chin should be taped to the board, and the lateral head and neck supported with sandbags or similar suitable devices. The trunk and pelvis should be strapped or taped to the board to minimize compression and traction of the spine by movement of the lower body. A rigid cervical collar should be placed around the neck of the child older than 1 year. Both the cervical collar and immobilization on a backboard are needed to achieve adequate cervical spine immobilization. While it is necessary to keep a patient immobilized until the assessment for cervical spine injury is completed, immobilization itself reduces forced vital capacity and often causes neck pain and stiffness that can persist for many hours. To minimize patient discomfort, evaluation should proceed deliberately with a goal of removing unnecessary immobilization rapidly.
After immobilization, the patient can be transported safely for radiographic investigation and neurosurgical consultation. A complete series of radiographs includes three views: a lateral, an anteroposterior, and an open-mouth view. Lateral cervical spine radiographs provide the most useful information, but they may not adequately demonstrate the area most likely to be injured in the younger child, C-I to C-2 (Figure 4). The anteroposterior view should be examined for vertebral body compression and symmetry of alignment of the vertebral bodies, facets, and pillars. The odontoid process can be visualized with an open-mouth view. The odontoid process should be symmetrically positioned between the arches of C-I, without any irregularities of its outline suggesting a fracture.8 In young, uncooperative children, this view may not be possible, and a reverse Waters view can be substituted. Computed tomography is more sensitive than plain radiographs in detecting fractures and dislocations, and should be considered when radiographs are normal, but signs or symptoms persist. Magnetic resonance imaging allows the spinal cord to be visualized and is the radiographic method of choice for assessing cord injury in association with neurologic deficits.
Because a multicenter study demonstrated improved neurologic outcomes in trauma victims older than 13 years who received methylprednisolone (50 mg/kg followed by an infusion of 5.4 mg/kg/hour for 24 hours), many specialists recommend its use in younger children.19 Broad-spectrum parenteral antibiotics should be given in penetrating cervical spine trauma, as the incidence of infection is 10%.
Pediatric cervical spine injury has a mortality of 59%; most of these victims die at the scene after catastrophic injury. This is because pediatrie cervical spine injuries often involve C-I to C-3, leading to paralysis of the muscles of respiration. The high mortality suggests that injury prevention is the best way to decrease mortality. For patients who survive to be evaluated in trauma centers, the initial neurologic examination is highly correlated with outcome. While children with complete spinal cord lesions have only a 10% chance of recovering any function, those with limited upper extremity sensory or motor deficits will recover completely in more than 50% of cases.
Injury prevention is always preferable to injury treatment. Age-appropriate car seat restraints can markedly decrease the likelihood of cervical spine injuries associated with motor vehicle collisions. Adolescents who participate in organized sports should be reminded of the benefits of conditioning the neck muscles by exercise, as increased neck girth is associated with a decreased frequency of cervical spine injuries. Those who play football and hockey should be instructed in the proper techniques of tackling and checking, using the shoulder and chest to transmit the force to opponents, rather than using the head and neck as an offensive weapon. While wearing a helmet is mandatory for head protection, it may increase the tendency to spear opponents with the head, which in turn may precipitate a serious cervical spine injury. Football and hockey helmets that fit improperly (particularly those that extend down the nape of the neck) are associated with more cervical spine injuries. Anticipatory guidance about the choice of swimming and diving sites is also important. Children with Down syndrome should be screened with lateral cervical spine radiographs prior to participation in sports and asked to abstain if evidence of ligamentous laxity is demonstrated.
Figure 4. Criteria for clearing the cervical spine: lateral view. 1) All seven vertebral bodies must be clearly seen, including the C-7 to T-1 junction. 2) Evaluate proper alignment of the posterior cervical line and the four lordotic curves: anterior longitudinal ligament line (A), the posterior longitudinal ligament line (B), the spinolaminal line (C), and the tips of the spinous processes (D). No discontinuities or step-offs should be seen in these lines. 3) Evaluate the predentai space (3), 4 to 5 mm is normal in children. 4) Evaluate each vertebra for fracture and increased or decreased density (suggestive of compression fracture). 5) Evaluate the intervertebral and interspinous spaces. Abrupt angulation of 11° at a single interspace is abnormal. 6) Evaluate if there is fanning of the spinous processes, suggestive of posterior ligament disruption. 7) Evaluate prevertebral soft-tissue distance; <7 mm at C-2 and <5 mm at C-3 to C-4 is considered normal. In children less than 2 years, this space may be widened if it is not an inspiratory film. 8) Evaluate the atlanto-occipital region for possible dislocation. (Modified from Barkin HM, Rosen P. Emergency Pediatrics. 3rd ed. Copyright (01990, Mosby-Year Book Ine, and Van Hare RS, Yaron M. The ring of C2 and evaluation of the cross-table lateral view of the cervical spine. Ann Emerg Meo. 1992;21 :734. Copyright ©1992.)
While cervical spine injuries are unusual in children, when they occur they frequently cause death or life-long disability. The primary care practitioner should be familiar with the signs and symptoms of cervical spine injuries, know the proper techniques of initial management, and engage in anticipatory guidance to prevent these injuries.
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