Pediatr Radiol (2009) 39:447–456 DOI 10.1007/s00247-008-1043-2
REVIEW
Pediatric cervical spine trauma imaging: a practical approach Alexia M. Egloff & Nadja Kadom & Gilbert Vezina & Dorothy Bulas
Received: 29 August 2008 / Revised: 4 October 2008 / Accepted: 6 October 2008 / Published online: 12 November 2008 # Springer-Verlag 2008
Abstract Cervical spine trauma in children is rare and the diagnosis can be challenging due to anatomical and biomechanical differences as compared to adults. A variety of algorithms have been used in adults to accurately diagnose injuries, but have not been fully studied in pediatric patients. In this article we review suggested imaging protocols and the general characteristics, types of injuries, and measurements used to diagnose cervical spine injuries in children. Keywords Cervical spine . Emergency . Trauma . Imaging . Children
tion, stage of development, and physiology and biomechanics of the cervical spine, as well as injury mechanisms [3, 7, 8, 13]. In addition, special concerns exist regarding the higher risk of radiation exposure in children [14, 15]. The primary objective of this paper is to review algorithms that have been recommended for and applied in the evaluation of the pediatric cervical spine after trauma. The various types of cervical spine injuries in children and useful measurement techniques have been fully described elsewhere; important characteristics are summarized in Tables 1 and 2, respectively. Strategies that can be implemented in the emergency and radiology departments in order to improve the imaging outcome are described.
Introduction Epidemiology of pediatric cervical spine injuries Although cervical spine injuries are relatively rare in pediatric patients, they can have devastating outcomes when misdiagnosed, including severe neurologic disabilities and even death [1–8]. An accurate and timely diagnosis is critical and requires a combination of clinical history, physical examination and appropriate imaging studies. Various well-established management guidelines exist for adults [9–12], but these may not apply to children. Use of adult cervical spine evaluation algorithms in children may not be appropriate because of significant differences in ability to obtain a reliable clinical examina-
A. M. Egloff (*) : N. Kadom : G. Vezina : D. Bulas Department of Imaging and Radiology, Children’s National Medical Center, 111 Michigan Ave, NW 1607 16th St., Washington, DC 20010, USA e-mail:
[email protected]
Cervical spine injuries occur in approximately 1–3% of pediatric trauma patients [2, 3, 7, 16, 17], and represent 37% [7] to 80% [6] of pediatric spine injuries following blunt trauma. Cervical spine injuries result in a higher incidence of neurologic deficits in patients younger than 8 years of age (62%) compared to older patients (47%) [8], and have higher mortality rates (15–28%) than in adults (11%) [7, 8]. Motor vehicle accidents (MVA) are the most common cause of pediatric cervical spine injuries [3, 13, 18]. Other causes of cervical spine injuries are age-dependent: patients younger than 8 years of age can have cervical injuries after minor trauma and falls; after 8 years, sports-related injuries play a more important role [3, 13, 19]. Sports-related injuries can be seen in children at risk for atlantoaxial instability, including Down syndrome, mucopolysaccharidosis type VI and Marfan syndrome, and in children with congenital spinal stenosis, such as achondroplasia [6].
Craniocervical arterial dissection
Subaxial injuries
C2 fractures
Facet fracture/dislocation
Body compression fracture
Hangman fracture
Odontoid fractures
Ligamentous disruption
Rotatory subluxation
Jefferson fracture (Ring of C1 fracture)
Fractures of the atlas
Atlantoaxial injuries
Rare, can be fatal. 2.5 times more common than in adults
Anterior dislocation Posterior dislocation Longitudinal distraction
Occiput-C1 injury
Unstable, associated with spinal cord syndromes Uncommon; can result in childhood stroke, likely secondary to thromboembolism. Mechanisms described: (1) direct blunt trauma to neck, (2) deceleration injuries with high shearing forces, (3) blunt intraoral trauma, and (4) basal skull fractures crossing petrous carotid canal. Mortality: 5–40%; neurologic morbidity 12–80%
After minor trauma. Present with painful torticollis and spasm of sternocleidomastoid muscle Type 1: Odontoid as pivot, no anterior displacement. Most common Type 2: Lateral mass as pivot, 3–5 mm anterior displacement. Associated with injury of transverse ligament Type 3: More than 5 mm anterior displacement. Abnormal transverse and alar ligaments Type 4: Posterior displacement of C1 Isolated transverse ligament injuries (rare in healthy patients); seen associated with rheumatoid diseases, bone dysplasias and anatomic anomalies (Klippel-Feil syndrome, Down syndrome and os odontoideum). Minor trauma can result in devastating neurologic injuries Most common cervical fracture in children. Usually through the synchondrosis Hyperextension injury with bilateral pars interarticularis fracture. In children, less common than C1 or odontoid fractures Rare in children. When present, frequently associated with severe sports-related or motor vehicle accidents in older children and adolescents Occurs with flexion and axial loading.
Less common than atlantooccipital and atlantoaxial dislocation. Jefferson fracture seen more commonly in adolescents resulting from motor vehicle or diving accidents
Characteristics
Type of injury
Table 1 Different types of injuries of the cervical spine and important characteristics in children [4, 5, 8, 34, 53].
Loss of vertebral height. May have retropulsed fragments that could result in cord injury Translational displacement of vertebrae in 50% Vascular wall irregularity, caliber changes of the vessel, filling defects, intimal flap, extravasation, and occlusion. Severe arterial stenosis with very slow flow, vessel irregularity and intimal flap are better appreciated with catheter angiography
Prevertebral soft-tissue swelling. Anterior odontoid displacement with dens tilted posteriorly Anterior displacement of C2 on C3 with widening of spinal canal
Abnormal predental space
Abnormal or obscured predental interval and asymmetry of lateral atlantoaxial joint spaces
Retropharyngeal swelling. Abnormal Wackenheim clivus line and condylar gap-more useful BDI, BAI and Power’s ratio can also be abnormal. If suspected, obtain CT of craniocervical junction. Asymmetry of distance between lateral masses of C1 and C2. If distance >8 mm, suspect instability. Decreased AP diameter of spinal canal. If no displacement, MRI shows fluid in synchondrosis
Radiographic presentation
448 Pediatr Radiol (2009) 39:447–456
Angulation of spinal column
Kaufman’s condylar gap (Fig. 8) Retropharyngeal space
Basion–axial interval (BAI) (Fig. 6) Power’s ratio (Fig. 7)
C1-C2 interspinous distance (Fig. 5) Basion–dens interval (BDI) (Fig. 6)
Predental interval (Fig. 4)
Wackenheim’s clivus line (Fig. 3)
C2 line (Fig. 2)
Spinolaminar line (Fig. 1)
Distance between basion and line along posterior surface of axis Distance between basion and posterior arch of C1 divided by distance between opisthion and anterior arch of atlas Distance between occipital condyles and condylar facets of atlas Distance between posterior pharyngeal surface and anterior vertebral body surface
Line along posterior aspect of C2 body and odontoid Line extending along posterior surface of clivus inferiorly to upper cervical spine Distance between posteroinferior surface of anterior arch of C1 and anterior surface of odontoid Distance between the spinous process of C1 and C2 Distance between the basion and tip of the dens
Line along anterior aspect of vertebral bodies Line along posterior aspect of spinous process of vertebrae Line along anterior surface of spinous process of vertebral bodies
Anterior cervical line (Fig. 1)
Posterior cervical line (Fig. 1)
How to measure
Parameter
1/2 to 2/3 of vertebral body AP diameter Kyphosis of up to 10–13°, considered normal in >6 years of age (as in adults)
