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Characteristics of pediatric cervical spine injuries
Characteristics of Pediatric Cervical Spine Injuries By Evan R. Kokoska, Martin S. Keller, Marcus C. Rallo, and Thomas R. Weber St Louis, Missouri
Purpose: The objective of this study was to assess the mechanisms and patterns of injury and o u t c o m e in children with cervical (C) spine trauma. Methods: We reviewed the National Pediatric Trauma Registry between April 1994 and March 1999 and identified (by ICD-9 criteria) all cases of blunt trauma victims with cervical fractures, dislocations, and spinal cord injuries w i t h o u t radiographic a b n o r m a l i t y (SCIWORA). Data are s h o w n as mean _+ SEM.
Results: During the 5-year period, the incidence of blunt C-spine injury was 1.6% (n = 408 of 24,740 total entries). Mean age was 10.5 +_ 0.3 (1 to 20) years, and 59% were boys, Leading mechanisms were m o t o r vehicle accidents (n = 179; 44%), sports (n = 66; 16%), and pedestrian injuries (n - 57, 14%). Y o u n g e r (~<10 years) children more often sustained high (C1 to C4) vs l o w (C5 to C7) injuries (85% v57%; P < .01) and also had a higher incidence of dislocations (31% v 2 0 % ; P < .01 ) and cord injuries (26% v 14%; P < .01 ), whereas older
LTHOUGH THE INCIDENCE of spinal cord injury is relatively low (1% to 2%) among pediatric trauma victims, 60% to 80% of all pediatric vertebral injuries are in the cervical (C) spine. This is in contrast to adults in whom C-spine injuries constitute 30% to 40% of all vertebral injuries.l,2 The biomechanical and anatomic features of the immature (or pediatric) C-spine account for a completely different pattern of C-spine injury when compared with that of the adult. 2 Peculiar aspects of the young pediatric C-spine include incomplete ossification, a unique vertebral configuration, and ligamentous laxity. Previous reports suggest that the pediatric C-spine may not take on characteristics of an adult C-spine until an age of 8 years. 3-6 Current recommendations regarding C-spine management are based primarily on class II and class III studies of predominantly adult patients. 7 Our main objective was to assess
From the Division of Pediatric Surgery, Department of Surgery, Saint Louis University Health Sciences Center and Cardinal Glennon Children's Hospital, St Louis, MO. Presented at the 31st Annual Meeting of the American Pediatric Surgical Association, Orlando, Florida, May 25-29, 2000. Address reprint requests to Thomas R. Weber, MD, Director of Pediatric Surgery, Cardinal Glennon Children's Hospital, 1465 South Grand Blvd, St Louis, MO 63104. Copyright © 2001 by W.B. Saunders Company 0022-3468/01/3601-0017503.00/0 doi: l O.l O53/jpsu.2001.20022 100
children had more C-spine fractures (66% v 43%; P < 0.01). Mortality rates (overall, 17%) were higher in y o u n g e r children (n = 180) w h e n c o m p a r e d with older children (n = 228; 30% v 7%; P < .01). Overall, the m a j o r i t y of deaths (93%) were associated with brain injuries. No children with cervical dislocations had neurologic sequelae. The preponderance of children with fractures (83%) also were w i t h o u t neurologic injury, whereas those associated with SCIWORA usually were (80%) partial. Overall, complete cord lesions were infrequent (4%).
Conclusions: These data, representing the largest series to date, confirm that blunt C-spine injuries in children are rare. Patterns of injury v a r y significantly according to child age. M a j o r neurologic sequelae in survivors is uncommon, does not correlate well with cord level, and rarely is complete. J Pediatr Surg 36:100-105. Copyright © 2001 by W.B. Saunders Company. INDEX WORDS: Pediatric, cervical spine, trauma.
the mechanisms and patterns of injury and outcome in children with C-spine trauma. MATERIALS AND METHODS The database of the National Pediatric Trauma Registry was reviewed during phase 3 (April 1994, to March 1999) and identified all cases of blunt trauma victims with C-spine injury. Data were sorted by International Classification of Diseases, 9th revision, Clinical Modification (ICD. 9 • CM) diagnosis as follows: fractures (805.00 to 805.19, 806.00 to 806.19), dislocations (839.00 to 839.18), and spinal cord injury without radiographic abnormality (SC1WORA; 952.00 to 952.09). Because the ICD • 9 • CM classification did not always designate a specific spinal cord level, injuries were categorized into either upper (C1 to C4) or lower (C5 to C7). No children were excluded from the study. Analysis of variance (ANOVA) using a Scheffe posterior contrast test was performed on all groups with continuous data because it is more strict than other ANOVA comparisons and is exact when group sizes are unequal. 8 Chi-square or Fisher's Exact test was used for analysis of nominal data. A P value less than .05 defined statistical significance, and all data are shown as mean + SEM. StatView 4.5 (Abacus Concepts, Inc, Berkeley, CA) was used for all statistical analyses.
RESULTS
During the 5-year period, 408 children (1.6%) were entered into the database with blunt C-spine injuries. Mean child age was 10.5 _+ 0.3 (1 to 20) years and 59% were boys. The age distribution of the children is depicted in Fig 1. Leading mechanisms of injury were motor vehicle collisions (n = 179; 44%), sports (n = 66; 16%), falls (n = 57; 14%), pedestrian injuries (n = 44; Journal of Pediatric Surgery, Vol 36, No 1 (January), 2001: pp 100-105
CERVICAL SPINE INJURIES
101
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Fig 1. Age distribution of children sustaining blunt C-spine injuries.
2
3
6
7
9 10 l l 12 13 14 15 16 17 18 19 20
8
Age (years) of sport and bicycle injuries. Young and old children had similar rates of motor vehicle collisions. Overall, the majority of the injuries (n = 284, 69.9%) occurred between C 1 and C4. Young children more often sustained high (C1 to C4) versus low (C5 to C7) injuries (85.3% v 56.9%; P < .01) when compared with old children. The mean age of children with high C-spine injuries (9.4 -+ 0.3 years) also was significantly lower than those with low injuries (12.8 -+ 0.4 years, P < .01). The relationship between child age and level of C-spine injury is depicted in Fig 3. The most common types of C-spine injuries were fractures (n = 228, 55.9%), followed by dislocations (n = 103, 25.2%) and SCIWORA (n = 77, 18.9%).
11%), and bicycle injuries (n = 25; 6%). Compared with all injured children involved in motor vehicle collisions,
children with C-spine injuries were more frequently unrestrained (80.1% v 58.4%; P < .01). The incidence of C-spine injuries associated with motor vehicle collisions (179 of 5,908, 3.0%) and sports (66 of 1,976, 3.3%) was higher than injuries associated with falls (57 of 7,148, 0.8%; P < .01) or bicycle (25 of 2,254, 1.1%; P < .01) and pedestrian (44 of 3,401, 1.3 %; P < .01) accidents. Mechanisms of injury in children with C-spine injuries, sorted by age group, are shown in Fig 2. Young children (1 to 10 years, n = 180) were more prone to falls and pedestrian accidents, whereas old children (11 to 20 years, n = 228) had a higher incidence 50-,-
5
4
n=179
@Young • Old
40 n=66
eH
.c~
30 n = 57
~
n = 44
t
2O
n=25 ~
10
MVC
Sports
Fall
Mechanism
Pedestrian
of Injury
Bicycle
Fig 2. Common mechanisms of injury in children, sorted by age group, sustaining blunt C-spine injuries (tP < ,01 v old [11 to 20 years] children, *P < .01 v young [1 to 10 years]), The number of children in each group is depicted above the respective column.
i02
KOKOSKA ET AL
100% 90% 80% - - 70%
o~
60% 50% 40% 30% 20% 10%
0% 1 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16 17 18 19 20
Age (years) Young children had a higher incidence of dislocations (31.2% v 20.4%; P < .01) and SCIWORA (26.7% v 14.5%; P < .01), whereas older children had more C-spine fractures (65.1% v 42.1%; P < .01). Mean patient ages were significantly lower in children with dislocations (9.3 -+ 0.5 years) and SCIWORA (9.3 _+ 0.6 years) when compared with those with fractures (11.4 _+ 0.4 years; P < .01). The relationship between patient age and the type of C-spine injury is shown in Fig 4. Overall, there were 69 (16.9%) deaths, the majority (92.8%) of which were associated with brain injuries. Mortality rates were significantly higher in young versus old children (30.0% v 6.6%; P < .01) and were highest in children after fails (40.3%), motor vehicle collisions
Fig 3. Relationship between patient age and level of C-spine injury (High, C1 to C4; Low, C5 to C7).
(20.1%), and bicycle accidents (20.0%). There were no sports-related deaths. Among the surviving children (n = 339), all those with cervical dislocations had no neurologic sequelae. The preponderance of children with fractures (83.0%) also were without neurologic injury, whereas syndromes associated with SCIWORA usually were (79.7%) partial. Overall, complete cord lesions were infrequent (4.4%). These data are depicted in Table 1. DISCUSSION
These data, representing the largest series to date, suggest that blunt C-spine injuries in children are rare. The current study is similar to other reports, which suggests that the incidence of blunt C-spine injuries in
100% 90% 80%
_~
70%
~.)
60%
.~
50% 40%
i
30%
20% 10%
O% Fig 4. Relationship between patient age and type of C-spine injury.
1
2
3
4
6 7 8
l0 11 12 13 14 15 16 17 18 19 20
Age (years)
CERVICAL SPINE INJURIES
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Table 1. Spinal Cord Syndromes in Survivors (n = 339) Anterior
Complete
Central
Partial
None
Fracture (n - 194; 57%)
2
8
1
22
161
Dislocation (n - 81; 24%)
0
0
O
0
81
SCIWORA (n = 64; 19%)
1
7
5
51
0
children is between 1% to 2% of all trauma victims requiring admission. 1 However, mortality rates in children with injured C-spines is high (15% to 20%), in large part because of associated lethal head injuries. 9 The most common mechanisms of C-spine injury are motor vehicle collisions, falls, sports-related accidents, and pedestrian and bicycle accidents. Similar to prior studies is our observation that younger children are more prone to C-spine injury after falls and pedestrian accidents, whereas older children more commonly sustain C-spine injury during sports and bicycling. However, children of all ages have similar rates of C-spine injury after motor vehicle collisions. 24,8-11 The current report confirms the data in the literature, which suggests that young children have a predilection for higher C-spine injuries. 1,2,4,5,6,9-11 In addition, as the current study suggests, young children have a higher incidence of C-spine dislocations and SCIWORA, whereas older children are more likely to sustain a C-spine fracture after blunt trauma. 5,6,9,12,13 These observations can be explained by the biomechanical and anatomic differences that exist in the developing pediatric C-spine. Young children have proportionally larger heads with an underdeveloped neck musculature and are thus more susceptible to flexion and extension injuries. In addition, the greater head-to-body ratio causes torque and acceleration stress to occur higher in the C-spine. Although the fulcrum of cervical motion is at C5 to C6 in adolescents and adults, it is much higher (C2 to C3) in young children. Physiologic anterior wedging of the upper Cspine in young children facilitates forward vertebral movement, causing the C-spine to be more prone to anterior dislocation. The articulating facet joints in young children are more horizontally oriented, leading to greater spine mobility and less stability. Finally, in a young child, the interspinous ligaments, cartilaginous end plates, and joint capsules have greater laxity and elasticity.3.4.5,9 As a child grows and matures, the C-spine becomes more like that of an adult. The neck musculature becomes stronger, and the size of the head becomes relatively smaller. The anterior vertebral bodies lose their wedge shape and become more rectangular. The articulating facet joints become more vertical. Finally, the interspinous ligaments and vertebral bodies mature and ossify. Thus, although the laxity and elasticity of the young pediatric C-spine may act to protect against spinal
column injury (fracture) during low energy trauma, these same characteristics seem to result in other types of injury (such as SCIWORA) when a young child sustains a high-energy impact? SCIWORA occurs in about 15% to 25% of all pediatric C-spine injuries and is an injury that is specific to children and extremely rare in adults, m,11,12 The mechanism of SCIWORA involves transient vertebral displacement with subsequent realignment to a normal configuration resulting in a damaged spinal cord with a normal-appearing vertebral column. SCIWORA occurs when the cord is stretched, torn, or contused because of the ligamentous laxity of the developing spine. The elasticity of the young spinal column is such that it can stretch up to 5 cm before rupture, whereas the spinal cord, which is anchored to the brachial plexus superiorly and the cauda equina inferiorly, ruptures after 5 to 6 mm of traction. H,12 Although our findings suggests that SCIWORA usually is associated with partial cord injuries, others have reported that spinal cord syndromes usually are (75%) complete. 12 Our data suggest that characteristics (level and type) of C-spine injuries in children do not trend toward that of an adult until age 10 to 11 years and do not equal that of an adult until late adolescence. This is in contrast to the data in the current literature, which support a clear transition at either age 83-6 or 9 years. 9,1°,13 Although the multiple vertebral ossification centers fuse at various ages, most epiphyseal plates are fused by 8 years of age. 2 The articulating facets become more vertical and ossify between 7 to 10 years. 2 Thus, our findings suggest that, although a child's C-spine may anatomically take on some of the characteristics of an adult at 8 years of age, the clinical patterns of injury may not parallel that of the adult until much later in life. For example, in the adult population, SC1WORA is extremely rare, the incidence of C-spine dislocation is approximately 15%, and the rate of upper C-spine injury is approximately 40%. 14 The current study (Figs 3 and 4) suggests that children approach the adult pattern of C-spine injury at about 15 years of age. Because patterns of injury do vary with child age, radiologic imaging in young and adolescent children must include the upper C-spine and take into account the higher incidence of ligamentous injury. C-spine injuries in children are preventable. In the current series, the majority (80%)of children involved in motor vehicle collisions were restrained improperly. Givens et al 3 reported a similar observation: In a study of
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all police-reported car collisions in the United States over a 1-year period, the incidence of the use of proper restraint was only 76% in infants and 41% in toddlers. The single strongest risk factor for injury after a motor vehicle collision was the nonuse of restraint (adjusted odds ratio of 2.7). 15 Other studies also have confirmed that age-appropriate car seat restraints markedly decrease the incidence and likelihood of C-spine injury associated with motor vehicle collisions. 12 Neck muscle conditioning, appropriate tackling and checking, proper-fitting helmets, and good attention to swimming and diving sites also have been reported to lessen the risk of C-spine injury during organized sports. 12 Our data confirm that the overall incidence of C-spine injuries in children is low. Mortality rate, unfortunately, is high and usually is related to concomitant head inju-
ries. Young children (---10 years) are more likely to sustain higher C-spine injuries with dislocations or SCIWORA. Contrary to other reports, the incidence of high C-spine injury and ligamentous injury remains high throughout early adolescence. Finally, major neurologic sequelae in survivors is u n c o m m o n and rarely is complete. Such data should be considered when evaluating and imaging children after blunt trauma. Imaging practices for C-spine clearance should take into account the greater propensity for high C-spine injury, ligamentous injury, and neurologic injury without bone abnormality.
ACKNOWLEDGMENT The authors thank Sue Schneps of the Research and TrainingCenter at Tufts UniversitySchool of Medicine(Boston,MA) for her assistance with assimilatingdata from the National Pediatric Trauma Registry.
REFERENCES 1. Dietrich AM, Ginn-PeaseME, Bartkowski HM, et al: Pediatric cervical spine fractures: Predominatelysubtle presentation. J Pediatr Surg 26:995-1000, 1991 2. Dickman CA, Rekate HL, Sonntag VKH, et al: Pediatric spinal trauma: Vertebral column and spinal cord injuries in children. Pediatr Neurosci 15:237-256, 1989 3. Givens TG, Polley KA, Smith GF, et al: Pediatric cervical spine injury: A three-year experience. J Trauma 41:310-314, 1996 4. Baker C, Kadish H, Schunk JE: Evaluationof pediatric cervical spine injuries. Am J Emerg Med 17:230-234, 1999 5. Nitecki S, Moir CR: Predictive factors in the outcome of traumatic cervical spine fracture in children. J Pediatr Surg 29:1409-1411, 1994 6. OrensteinJB, Klein BL, GotschallCS, et al: Age and outcome in pediatric cervicalspine injury: 11-yearexperience. Pediatr Emerg Care 10:132-137, 1994 7. Pasquale M, Fabian TC: Practice management guidelines for trauma from the Eastern Association for the Surgery of Trauma. J Trauma 44:941-957, 1998 8. Zarling EJ, Piontek F, Klemka-WaldenL, et al: The effect of
gastroenterologytrainingon the efficiencyand cost of care provided to patients with diverticulitis.Gastroenterology112:1859-1862, 1997 9. Eleraky MA, Theodore N, Adams M, et al: Pediatric cervical spine injuries: Report of 102 cases and review of the literature. J Neurosurg 92:12-17, 2000 10. FinchGD, Barnes MJ: Major cervical spine injuries in children and adolescents. J Pediatr Orthop 18:811-814, 1998 11. Kriss VM, Kriss TC: SCIWORA (spinal cord injury without radiographic abnormality)in infants and children.Clin Pediatr 35:119124, 1996 12. Manary MJ, Jaffe DM: Cervical spine injuries in children. Pediatr Annals 25:423-428, 1996 13. HadleyMN, ZabramskiJM, BrownerCM, et al: Pediatric spinal trauma: Review of 122 cases of spinal cord and vertebral column injuries. J Neurosurg 68:18-24, 1988 14. WoodringJH, Lee C: Limitationsof cervicalradiography in the evaluation of acute cervical trauma. J Trauma 34:32-39, 1993 15. Johnston C, Rivara FP, Soderberg R: Children in car crashes: Analysisof data for injury and use of restraints. Pediatrics 93:960-965, 1994
Discussion J. Tepas (Jacksonville, FL): I was fascinated by the study primarily because we have examined the entire NPTR, almost 75,000 cases, and found exactly the same thing, which is the good news. The real practical concern, however, is that in this very small proportion of patients there is a very real bit of morbidity and mortality attached to it. What exactly are your recommendations about finding those patients out and to put in different parlance clearing the C-spine? E.R. Kokoska (response): I think one thing this suggests is that any kind of radiologic protocol for children involved with blunt trauma must include the high Cspine. The other thing is, for younger children with a high index of suspicion in whom you cannot examine for ligamentous injury, I think one should have a low thresh-
old for other kind of imaging studies such as magnetic resonance imaging. W. Hardin (Birmingham, AL): We reported about 3 years ago our experience in Birmingham and found some conflicting results in which there really was a distribution throughout the cervical spine, even in the younger children. I would emphasize to the group it is not so much the high lesions that you are looking for; it is the hidden low lesions that you are looking for. It is the workup that becomes critical in identifying those patients. We have incorporated the CT scan very early on in evaluating some of these patients, and I again would ask you, how are you doing that at your institution? Do you have a protocol for looking at these kids with the more advanced imaging techniques?
CERVICAL SPINE INJURIES
E.R. Kokoska (response): CAT scan is not routinely used with the exception of some of the younger adolescents in whom you may not image the lower C-spine, and if right off the bat we can tell that we need a CAT scan for other reasons and that it is going to be difficult to image C6 and C7, we routinely get the CAT scan right away. A. Cooper (New York, NY): Prehospital immobilization of the child especially the young child with suspected spinal cord injury remains a vexing problem. The collars do not fit well. They are frequently improperly applied, and of course the large posterior occiput does tend to force the head forward into flexion even if the collar is in place. I wondered if you were able to identify any risk factors that might identify those patients who might especially require spinal immobilization to give some better guidance to our prehospital colleagues. E.R. Kokoska (response): Not from this data set; in the data base there is a category for whether the child was immobilized in pretransfer, and the majority were, so it is hard to sort out specific recommendations with regard to that. The only thing I can think of, there was a paper, and I think it was out of Columbus several years ago, that looked at how important the angle is with regard to the head and the neck, and they did not find a big difference in their mechanistic study. J. Groner (Columbus, OH): C-spine injuries are something I wrestle with every day, and they get me in trouble with orthopedics and anesthesia, and so forth. We have tended to get away from the term SCIWORA in Columbus because most of the patients with the neurologic injuries without fractures will have abnormalities on MRI. We jokingly call it SCAWOFA, which stands for spinal cord abnormality without fracture apparent. I was wondering what your experience is doing MRIs in these patients. E.R. Kokoska (response): That is a good point. Usually you pick something up on MRI that you miss on CAT scan or plain films.
105
P. Trefogli (Lima, Peru): In the infant age group of trauma patients, which usually are the patients that do not necessarily come openly as an abused group of patients, what is the survival rate and what are the associated lesions? E.R. Kokoska (response): I did not have time to present the in-detail data on mortality, but mortality was much higher in the younger children in this study. It, as well, was almost uniformly associated with concomitant head injuries. R. Powell (Mobile, AL): I am afraid that your conclusions about dislocations and no neurologic injury may be incorrect. Are there any atlantooccipital dislocations in your series? This is a very devastating injury to children, which frequently results in death at the scene of the accident, although with improving EMSC we are seeing several of these types of injuries presenting to our emergency room. To get the complete incidence of that, you really need to look at the medical examiner's experience because frequently the medical examiner is the first one to get those patients. Did you have any atlantooccipital dislocations in this series? E.R. Kokoska (response): There were, but you are exactly right that probably many children had them that were not entered into this data base that did not reach the emergency room. With regard to your first point, I agree we all have seen children with dislocations who have a spinal cord injury, so I do not know what to make of that observation. M. Statter (Richmond, VA): In terms of your prehospital data, do you have any information on how these children were restrained, and can you make any recommendations, particularly the 4 to 9-year-old age group, which has outgrown the infant car seat? E.R. Kokoska (response): Not based upon the current data set.
Purpose: The objective of this study was to assess the mechanisms and patterns of injury and o u t c o m e in children with cervical (C) spine trauma. Methods: We reviewed the National Pediatric Trauma Registry between April 1994 and March 1999 and identified (by ICD-9 criteria) all cases of blunt trauma victims with cervical fractures, dislocations, and spinal cord injuries w i t h o u t radiographic a b n o r m a l i t y (SCIWORA). Data are s h o w n as mean _+ SEM.
Results: During the 5-year period, the incidence of blunt C-spine injury was 1.6% (n = 408 of 24,740 total entries). Mean age was 10.5 +_ 0.3 (1 to 20) years, and 59% were boys, Leading mechanisms were m o t o r vehicle accidents (n = 179; 44%), sports (n = 66; 16%), and pedestrian injuries (n - 57, 14%). Y o u n g e r (~<10 years) children more often sustained high (C1 to C4) vs l o w (C5 to C7) injuries (85% v57%; P < .01) and also had a higher incidence of dislocations (31% v 2 0 % ; P < .01 ) and cord injuries (26% v 14%; P < .01 ), whereas older
LTHOUGH THE INCIDENCE of spinal cord injury is relatively low (1% to 2%) among pediatric trauma victims, 60% to 80% of all pediatric vertebral injuries are in the cervical (C) spine. This is in contrast to adults in whom C-spine injuries constitute 30% to 40% of all vertebral injuries.l,2 The biomechanical and anatomic features of the immature (or pediatric) C-spine account for a completely different pattern of C-spine injury when compared with that of the adult. 2 Peculiar aspects of the young pediatric C-spine include incomplete ossification, a unique vertebral configuration, and ligamentous laxity. Previous reports suggest that the pediatric C-spine may not take on characteristics of an adult C-spine until an age of 8 years. 3-6 Current recommendations regarding C-spine management are based primarily on class II and class III studies of predominantly adult patients. 7 Our main objective was to assess
From the Division of Pediatric Surgery, Department of Surgery, Saint Louis University Health Sciences Center and Cardinal Glennon Children's Hospital, St Louis, MO. Presented at the 31st Annual Meeting of the American Pediatric Surgical Association, Orlando, Florida, May 25-29, 2000. Address reprint requests to Thomas R. Weber, MD, Director of Pediatric Surgery, Cardinal Glennon Children's Hospital, 1465 South Grand Blvd, St Louis, MO 63104. Copyright © 2001 by W.B. Saunders Company 0022-3468/01/3601-0017503.00/0 doi: l O.l O53/jpsu.2001.20022 100
children had more C-spine fractures (66% v 43%; P < 0.01). Mortality rates (overall, 17%) were higher in y o u n g e r children (n = 180) w h e n c o m p a r e d with older children (n = 228; 30% v 7%; P < .01). Overall, the m a j o r i t y of deaths (93%) were associated with brain injuries. No children with cervical dislocations had neurologic sequelae. The preponderance of children with fractures (83%) also were w i t h o u t neurologic injury, whereas those associated with SCIWORA usually were (80%) partial. Overall, complete cord lesions were infrequent (4%).
Conclusions: These data, representing the largest series to date, confirm that blunt C-spine injuries in children are rare. Patterns of injury v a r y significantly according to child age. M a j o r neurologic sequelae in survivors is uncommon, does not correlate well with cord level, and rarely is complete. J Pediatr Surg 36:100-105. Copyright © 2001 by W.B. Saunders Company. INDEX WORDS: Pediatric, cervical spine, trauma.
the mechanisms and patterns of injury and outcome in children with C-spine trauma. MATERIALS AND METHODS The database of the National Pediatric Trauma Registry was reviewed during phase 3 (April 1994, to March 1999) and identified all cases of blunt trauma victims with C-spine injury. Data were sorted by International Classification of Diseases, 9th revision, Clinical Modification (ICD. 9 • CM) diagnosis as follows: fractures (805.00 to 805.19, 806.00 to 806.19), dislocations (839.00 to 839.18), and spinal cord injury without radiographic abnormality (SC1WORA; 952.00 to 952.09). Because the ICD • 9 • CM classification did not always designate a specific spinal cord level, injuries were categorized into either upper (C1 to C4) or lower (C5 to C7). No children were excluded from the study. Analysis of variance (ANOVA) using a Scheffe posterior contrast test was performed on all groups with continuous data because it is more strict than other ANOVA comparisons and is exact when group sizes are unequal. 8 Chi-square or Fisher's Exact test was used for analysis of nominal data. A P value less than .05 defined statistical significance, and all data are shown as mean + SEM. StatView 4.5 (Abacus Concepts, Inc, Berkeley, CA) was used for all statistical analyses.
RESULTS
During the 5-year period, 408 children (1.6%) were entered into the database with blunt C-spine injuries. Mean child age was 10.5 _+ 0.3 (1 to 20) years and 59% were boys. The age distribution of the children is depicted in Fig 1. Leading mechanisms of injury were motor vehicle collisions (n = 179; 44%), sports (n = 66; 16%), falls (n = 57; 14%), pedestrian injuries (n = 44; Journal of Pediatric Surgery, Vol 36, No 1 (January), 2001: pp 100-105
CERVICAL SPINE INJURIES
101
45 40
35.,
"~
30-
o~
~
2s-
z.
20-
~
15-
Z
lO-
0
1
Fig 1. Age distribution of children sustaining blunt C-spine injuries.
2
3
6
7
9 10 l l 12 13 14 15 16 17 18 19 20
8
Age (years) of sport and bicycle injuries. Young and old children had similar rates of motor vehicle collisions. Overall, the majority of the injuries (n = 284, 69.9%) occurred between C 1 and C4. Young children more often sustained high (C1 to C4) versus low (C5 to C7) injuries (85.3% v 56.9%; P < .01) when compared with old children. The mean age of children with high C-spine injuries (9.4 -+ 0.3 years) also was significantly lower than those with low injuries (12.8 -+ 0.4 years, P < .01). The relationship between child age and level of C-spine injury is depicted in Fig 3. The most common types of C-spine injuries were fractures (n = 228, 55.9%), followed by dislocations (n = 103, 25.2%) and SCIWORA (n = 77, 18.9%).
11%), and bicycle injuries (n = 25; 6%). Compared with all injured children involved in motor vehicle collisions,
children with C-spine injuries were more frequently unrestrained (80.1% v 58.4%; P < .01). The incidence of C-spine injuries associated with motor vehicle collisions (179 of 5,908, 3.0%) and sports (66 of 1,976, 3.3%) was higher than injuries associated with falls (57 of 7,148, 0.8%; P < .01) or bicycle (25 of 2,254, 1.1%; P < .01) and pedestrian (44 of 3,401, 1.3 %; P < .01) accidents. Mechanisms of injury in children with C-spine injuries, sorted by age group, are shown in Fig 2. Young children (1 to 10 years, n = 180) were more prone to falls and pedestrian accidents, whereas old children (11 to 20 years, n = 228) had a higher incidence 50-,-
5
4
n=179
@Young • Old
40 n=66
eH
.c~
30 n = 57
~
n = 44
t
2O
n=25 ~
10
MVC
Sports
Fall
Mechanism
Pedestrian
of Injury
Bicycle
Fig 2. Common mechanisms of injury in children, sorted by age group, sustaining blunt C-spine injuries (tP < ,01 v old [11 to 20 years] children, *P < .01 v young [1 to 10 years]), The number of children in each group is depicted above the respective column.
i02
KOKOSKA ET AL
100% 90% 80% - - 70%
o~
60% 50% 40% 30% 20% 10%
0% 1 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16 17 18 19 20
Age (years) Young children had a higher incidence of dislocations (31.2% v 20.4%; P < .01) and SCIWORA (26.7% v 14.5%; P < .01), whereas older children had more C-spine fractures (65.1% v 42.1%; P < .01). Mean patient ages were significantly lower in children with dislocations (9.3 -+ 0.5 years) and SCIWORA (9.3 _+ 0.6 years) when compared with those with fractures (11.4 _+ 0.4 years; P < .01). The relationship between patient age and the type of C-spine injury is shown in Fig 4. Overall, there were 69 (16.9%) deaths, the majority (92.8%) of which were associated with brain injuries. Mortality rates were significantly higher in young versus old children (30.0% v 6.6%; P < .01) and were highest in children after fails (40.3%), motor vehicle collisions
Fig 3. Relationship between patient age and level of C-spine injury (High, C1 to C4; Low, C5 to C7).
(20.1%), and bicycle accidents (20.0%). There were no sports-related deaths. Among the surviving children (n = 339), all those with cervical dislocations had no neurologic sequelae. The preponderance of children with fractures (83.0%) also were without neurologic injury, whereas syndromes associated with SCIWORA usually were (79.7%) partial. Overall, complete cord lesions were infrequent (4.4%). These data are depicted in Table 1. DISCUSSION
These data, representing the largest series to date, suggest that blunt C-spine injuries in children are rare. The current study is similar to other reports, which suggests that the incidence of blunt C-spine injuries in
100% 90% 80%
_~
70%
~.)
60%
.~
50% 40%
i
30%
20% 10%
O% Fig 4. Relationship between patient age and type of C-spine injury.
1
2
3
4
6 7 8
l0 11 12 13 14 15 16 17 18 19 20
Age (years)
CERVICAL SPINE INJURIES
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Table 1. Spinal Cord Syndromes in Survivors (n = 339) Anterior
Complete
Central
Partial
None
Fracture (n - 194; 57%)
2
8
1
22
161
Dislocation (n - 81; 24%)
0
0
O
0
81
SCIWORA (n = 64; 19%)
1
7
5
51
0
children is between 1% to 2% of all trauma victims requiring admission. 1 However, mortality rates in children with injured C-spines is high (15% to 20%), in large part because of associated lethal head injuries. 9 The most common mechanisms of C-spine injury are motor vehicle collisions, falls, sports-related accidents, and pedestrian and bicycle accidents. Similar to prior studies is our observation that younger children are more prone to C-spine injury after falls and pedestrian accidents, whereas older children more commonly sustain C-spine injury during sports and bicycling. However, children of all ages have similar rates of C-spine injury after motor vehicle collisions. 24,8-11 The current report confirms the data in the literature, which suggests that young children have a predilection for higher C-spine injuries. 1,2,4,5,6,9-11 In addition, as the current study suggests, young children have a higher incidence of C-spine dislocations and SCIWORA, whereas older children are more likely to sustain a C-spine fracture after blunt trauma. 5,6,9,12,13 These observations can be explained by the biomechanical and anatomic differences that exist in the developing pediatric C-spine. Young children have proportionally larger heads with an underdeveloped neck musculature and are thus more susceptible to flexion and extension injuries. In addition, the greater head-to-body ratio causes torque and acceleration stress to occur higher in the C-spine. Although the fulcrum of cervical motion is at C5 to C6 in adolescents and adults, it is much higher (C2 to C3) in young children. Physiologic anterior wedging of the upper Cspine in young children facilitates forward vertebral movement, causing the C-spine to be more prone to anterior dislocation. The articulating facet joints in young children are more horizontally oriented, leading to greater spine mobility and less stability. Finally, in a young child, the interspinous ligaments, cartilaginous end plates, and joint capsules have greater laxity and elasticity.3.4.5,9 As a child grows and matures, the C-spine becomes more like that of an adult. The neck musculature becomes stronger, and the size of the head becomes relatively smaller. The anterior vertebral bodies lose their wedge shape and become more rectangular. The articulating facet joints become more vertical. Finally, the interspinous ligaments and vertebral bodies mature and ossify. Thus, although the laxity and elasticity of the young pediatric C-spine may act to protect against spinal
column injury (fracture) during low energy trauma, these same characteristics seem to result in other types of injury (such as SCIWORA) when a young child sustains a high-energy impact? SCIWORA occurs in about 15% to 25% of all pediatric C-spine injuries and is an injury that is specific to children and extremely rare in adults, m,11,12 The mechanism of SCIWORA involves transient vertebral displacement with subsequent realignment to a normal configuration resulting in a damaged spinal cord with a normal-appearing vertebral column. SCIWORA occurs when the cord is stretched, torn, or contused because of the ligamentous laxity of the developing spine. The elasticity of the young spinal column is such that it can stretch up to 5 cm before rupture, whereas the spinal cord, which is anchored to the brachial plexus superiorly and the cauda equina inferiorly, ruptures after 5 to 6 mm of traction. H,12 Although our findings suggests that SCIWORA usually is associated with partial cord injuries, others have reported that spinal cord syndromes usually are (75%) complete. 12 Our data suggest that characteristics (level and type) of C-spine injuries in children do not trend toward that of an adult until age 10 to 11 years and do not equal that of an adult until late adolescence. This is in contrast to the data in the current literature, which support a clear transition at either age 83-6 or 9 years. 9,1°,13 Although the multiple vertebral ossification centers fuse at various ages, most epiphyseal plates are fused by 8 years of age. 2 The articulating facets become more vertical and ossify between 7 to 10 years. 2 Thus, our findings suggest that, although a child's C-spine may anatomically take on some of the characteristics of an adult at 8 years of age, the clinical patterns of injury may not parallel that of the adult until much later in life. For example, in the adult population, SC1WORA is extremely rare, the incidence of C-spine dislocation is approximately 15%, and the rate of upper C-spine injury is approximately 40%. 14 The current study (Figs 3 and 4) suggests that children approach the adult pattern of C-spine injury at about 15 years of age. Because patterns of injury do vary with child age, radiologic imaging in young and adolescent children must include the upper C-spine and take into account the higher incidence of ligamentous injury. C-spine injuries in children are preventable. In the current series, the majority (80%)of children involved in motor vehicle collisions were restrained improperly. Givens et al 3 reported a similar observation: In a study of
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KOKOSKA ET AL
all police-reported car collisions in the United States over a 1-year period, the incidence of the use of proper restraint was only 76% in infants and 41% in toddlers. The single strongest risk factor for injury after a motor vehicle collision was the nonuse of restraint (adjusted odds ratio of 2.7). 15 Other studies also have confirmed that age-appropriate car seat restraints markedly decrease the incidence and likelihood of C-spine injury associated with motor vehicle collisions. 12 Neck muscle conditioning, appropriate tackling and checking, proper-fitting helmets, and good attention to swimming and diving sites also have been reported to lessen the risk of C-spine injury during organized sports. 12 Our data confirm that the overall incidence of C-spine injuries in children is low. Mortality rate, unfortunately, is high and usually is related to concomitant head inju-
ries. Young children (---10 years) are more likely to sustain higher C-spine injuries with dislocations or SCIWORA. Contrary to other reports, the incidence of high C-spine injury and ligamentous injury remains high throughout early adolescence. Finally, major neurologic sequelae in survivors is u n c o m m o n and rarely is complete. Such data should be considered when evaluating and imaging children after blunt trauma. Imaging practices for C-spine clearance should take into account the greater propensity for high C-spine injury, ligamentous injury, and neurologic injury without bone abnormality.
ACKNOWLEDGMENT The authors thank Sue Schneps of the Research and TrainingCenter at Tufts UniversitySchool of Medicine(Boston,MA) for her assistance with assimilatingdata from the National Pediatric Trauma Registry.
REFERENCES 1. Dietrich AM, Ginn-PeaseME, Bartkowski HM, et al: Pediatric cervical spine fractures: Predominatelysubtle presentation. J Pediatr Surg 26:995-1000, 1991 2. Dickman CA, Rekate HL, Sonntag VKH, et al: Pediatric spinal trauma: Vertebral column and spinal cord injuries in children. Pediatr Neurosci 15:237-256, 1989 3. Givens TG, Polley KA, Smith GF, et al: Pediatric cervical spine injury: A three-year experience. J Trauma 41:310-314, 1996 4. Baker C, Kadish H, Schunk JE: Evaluationof pediatric cervical spine injuries. Am J Emerg Med 17:230-234, 1999 5. Nitecki S, Moir CR: Predictive factors in the outcome of traumatic cervical spine fracture in children. J Pediatr Surg 29:1409-1411, 1994 6. OrensteinJB, Klein BL, GotschallCS, et al: Age and outcome in pediatric cervicalspine injury: 11-yearexperience. Pediatr Emerg Care 10:132-137, 1994 7. Pasquale M, Fabian TC: Practice management guidelines for trauma from the Eastern Association for the Surgery of Trauma. J Trauma 44:941-957, 1998 8. Zarling EJ, Piontek F, Klemka-WaldenL, et al: The effect of
gastroenterologytrainingon the efficiencyand cost of care provided to patients with diverticulitis.Gastroenterology112:1859-1862, 1997 9. Eleraky MA, Theodore N, Adams M, et al: Pediatric cervical spine injuries: Report of 102 cases and review of the literature. J Neurosurg 92:12-17, 2000 10. FinchGD, Barnes MJ: Major cervical spine injuries in children and adolescents. J Pediatr Orthop 18:811-814, 1998 11. Kriss VM, Kriss TC: SCIWORA (spinal cord injury without radiographic abnormality)in infants and children.Clin Pediatr 35:119124, 1996 12. Manary MJ, Jaffe DM: Cervical spine injuries in children. Pediatr Annals 25:423-428, 1996 13. HadleyMN, ZabramskiJM, BrownerCM, et al: Pediatric spinal trauma: Review of 122 cases of spinal cord and vertebral column injuries. J Neurosurg 68:18-24, 1988 14. WoodringJH, Lee C: Limitationsof cervicalradiography in the evaluation of acute cervical trauma. J Trauma 34:32-39, 1993 15. Johnston C, Rivara FP, Soderberg R: Children in car crashes: Analysisof data for injury and use of restraints. Pediatrics 93:960-965, 1994
Discussion J. Tepas (Jacksonville, FL): I was fascinated by the study primarily because we have examined the entire NPTR, almost 75,000 cases, and found exactly the same thing, which is the good news. The real practical concern, however, is that in this very small proportion of patients there is a very real bit of morbidity and mortality attached to it. What exactly are your recommendations about finding those patients out and to put in different parlance clearing the C-spine? E.R. Kokoska (response): I think one thing this suggests is that any kind of radiologic protocol for children involved with blunt trauma must include the high Cspine. The other thing is, for younger children with a high index of suspicion in whom you cannot examine for ligamentous injury, I think one should have a low thresh-
old for other kind of imaging studies such as magnetic resonance imaging. W. Hardin (Birmingham, AL): We reported about 3 years ago our experience in Birmingham and found some conflicting results in which there really was a distribution throughout the cervical spine, even in the younger children. I would emphasize to the group it is not so much the high lesions that you are looking for; it is the hidden low lesions that you are looking for. It is the workup that becomes critical in identifying those patients. We have incorporated the CT scan very early on in evaluating some of these patients, and I again would ask you, how are you doing that at your institution? Do you have a protocol for looking at these kids with the more advanced imaging techniques?
CERVICAL SPINE INJURIES
E.R. Kokoska (response): CAT scan is not routinely used with the exception of some of the younger adolescents in whom you may not image the lower C-spine, and if right off the bat we can tell that we need a CAT scan for other reasons and that it is going to be difficult to image C6 and C7, we routinely get the CAT scan right away. A. Cooper (New York, NY): Prehospital immobilization of the child especially the young child with suspected spinal cord injury remains a vexing problem. The collars do not fit well. They are frequently improperly applied, and of course the large posterior occiput does tend to force the head forward into flexion even if the collar is in place. I wondered if you were able to identify any risk factors that might identify those patients who might especially require spinal immobilization to give some better guidance to our prehospital colleagues. E.R. Kokoska (response): Not from this data set; in the data base there is a category for whether the child was immobilized in pretransfer, and the majority were, so it is hard to sort out specific recommendations with regard to that. The only thing I can think of, there was a paper, and I think it was out of Columbus several years ago, that looked at how important the angle is with regard to the head and the neck, and they did not find a big difference in their mechanistic study. J. Groner (Columbus, OH): C-spine injuries are something I wrestle with every day, and they get me in trouble with orthopedics and anesthesia, and so forth. We have tended to get away from the term SCIWORA in Columbus because most of the patients with the neurologic injuries without fractures will have abnormalities on MRI. We jokingly call it SCAWOFA, which stands for spinal cord abnormality without fracture apparent. I was wondering what your experience is doing MRIs in these patients. E.R. Kokoska (response): That is a good point. Usually you pick something up on MRI that you miss on CAT scan or plain films.
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P. Trefogli (Lima, Peru): In the infant age group of trauma patients, which usually are the patients that do not necessarily come openly as an abused group of patients, what is the survival rate and what are the associated lesions? E.R. Kokoska (response): I did not have time to present the in-detail data on mortality, but mortality was much higher in the younger children in this study. It, as well, was almost uniformly associated with concomitant head injuries. R. Powell (Mobile, AL): I am afraid that your conclusions about dislocations and no neurologic injury may be incorrect. Are there any atlantooccipital dislocations in your series? This is a very devastating injury to children, which frequently results in death at the scene of the accident, although with improving EMSC we are seeing several of these types of injuries presenting to our emergency room. To get the complete incidence of that, you really need to look at the medical examiner's experience because frequently the medical examiner is the first one to get those patients. Did you have any atlantooccipital dislocations in this series? E.R. Kokoska (response): There were, but you are exactly right that probably many children had them that were not entered into this data base that did not reach the emergency room. With regard to your first point, I agree we all have seen children with dislocations who have a spinal cord injury, so I do not know what to make of that observation. M. Statter (Richmond, VA): In terms of your prehospital data, do you have any information on how these children were restrained, and can you make any recommendations, particularly the 4 to 9-year-old age group, which has outgrown the infant car seat? E.R. Kokoska (response): Not based upon the current data set.