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Clearing the Pediatric C-Spine. Kelly R. Millar, MD, FRCPC Emergency Physician, Alberta Children’s Hospital Assistant Professor, University of Calgary. Overview. Epidemiology Anatomic considerations Clearing the pediatric c-spine Who needs imaging? What films should be ordered?
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Clearing the Pediatric C-Spine Kelly R. Millar, MD, FRCPC Emergency Physician, Alberta Children’s Hospital Assistant Professor, University of Calgary
Overview • Epidemiology • Anatomic considerations • Clearing the pediatric c-spine • Who needs imaging? • What films should be ordered? • Who needs a CT/MRI? • Interpretation of Pediatric c-spine films • Cases
Epidemiology of PediatricCervical Spine Injury • 5% of all spinal cord injuries occur in children • 1000 pediatric spinal cord injuries in the US each year • 80% of spinal injuries in children < 8 yrs are cervical (vs 30-40% in adults)
Epidemiology • Many small case series • Often include up to age 20, so data very skewed to older “children” • 2 recent large pediatric data sources have fair number of younger children: • The largest prospective series is the pediatric subset of the NEXUS trial • The largest retrospective series comes from the National Pediatric Trauma Registry
National Pediatric Trauma Registry • Prospective, multi-center database • Includes ages 0-20 • Primary diagnosis traumatic injury • Patel et al (2001) J Ped Surg • 10 yr review (1988-98) • > 75,000 pediatric injuries in database • 1.5% had cervical spine injury (N = 1098)
National Pediatric Trauma RegistryKokoska et al (2001) J Ped Surg • 6 year review of same database • 1994 – 99 • Age distribution of c-spine injuries → • Younger age groups well represented Age (yrs)
Do children have the same injury patterns as adults? NO! • Injuries differ in location and type Why? • Developing spine has unique anatomy
Anatomic Considerations • Large head • Torque and acceleration stress occur higher in the c-spine • Fulcrum of motion C2-C3 in young children (vs C5-C6 in adults) • Younger children have an increased incidence of high C-spine injury
Location of InjuryNational Pediatric Trauma Registry Kokoska et al (2001) J Ped Surg Patel et al (2001) J Ped Surg Age
anterior wedging of vertebral bodies • horizontal alignment of facet joints • Children prone to anterior dislocation Young Child Mature University of Hawaii (www.hawaii.edu/medicine/pediatrics/pemxray)
Underdeveloped neck musculature • Ligamentous laxity • Younger children have an increased incidence of ligamentous injury
Believed that the laxity of the peds spine acts to protect against spinal fracture in low energy trauma, however, may lead to SCIWORA in high-energy trauma • More on SCIWORA in a moment…
Type of injury National Pediatric Trauma Registry: Kokoska et al (2001) J Ped Surg
How common are neuro deficits? National Pediatric Trauma Registry:Patel et al (2001) J Ped Surg
What is SCIWORA? • Def: Spinal cord injury without radiographic abnormality on plain film or CT • Mechanism: transient vertebral displacement with subsequent realignment resulting in damaged spinal cord and normal appearing vertebral column • Young spinal column can stretch up to 5cm • Spinal cord ruptures after 5mm of traction
SCIWORA • How common is it? • Literature extremely inconsistent with definition and incidence • Reported as 0-50% of peds spinal cord injuries • National Pediatric Trauma Registry: 17% • NEXUS: none!!
SCIWORA – case series Common themes: • Up to half may have delayed onset of symptoms (usually within 48 hrs) • SCI can be severe • Chance of recovery low if complete • May be related to spinal cord infarction
Epidemiology: Bottom Line • C-spine injuries in children are rare, but they do occur in about 1.5% of blunt trauma patients • In young children, be on look out for: • High c-spine injury • Ligamentous injury
Begins in Prehospital Setting: Immobilization • Aim for “neutral position” • Big head • When laying flat on backboard, neck is flexed • Must accommodate large occiput, using either an occipital depression or padding under the torso
Immobilization • Best immobilization achieved by modified spine board, rigid collar and taping • Too large a collar can distract the neck and worsen an injury – blocks are preferable to a poorly fitting collar
OK… Now the collar’s on…How do I get it off? Challenges: • Preverbal or crying children: • Difficult to assess tenderness • Difficult to perform detailed neurologic exam Questions: • Who needs imaging? • What type of imaging is needed? • When do I need a CT or MRI?
Clearing the Pediatric C-SpinePART 1: Who needs imaging? Is there any pediatric evidence? • 1 prospective study • Peds subset of NEXUS – Viccellio et al • 1 retrospective study • Isolated head injuries – Laham et al
Imaging – Peds subset of NEXUSViccellio et al (2001) Pediatrics • Prospective study of patients with blunt trauma + cervical spine radiography • Used 5 low-risk criteria: • No midline cervical tenderness • No evidence of intoxication • No altered level of consciousness • No focal neurological deficit • No painful distracting injury • If all 5 criteria met – considered low risk
NEXUS – peds subset • 3065 patients < 18 years (9% of NEXUS) • Total # c-spine injuries: 30 • 603 / 3065 considered “low risk” (20%) • All low risk patients had negative radiographic evaluations (100% sensitive)
NEXUS – peds subset • Problem: Numbers are small, so 95% CI for sensitivity: 87.8% - 100% • Problem: Very few injuries in younger kids • Grouped as follows: • 0-2 (lack of verbal skills) N = 88 (0) • 3-8 (immature cervical spine) N = 817 (4) • 9-17 (older children) N = 2150 (26)
NEXUS – peds subset • Bottom line: • Authors “cautiously endorse” the use of the NEXUS criteria in children over age 8 • Not enough power to ensure that the tool is safe to use in younger children • However, authors state that there is not a single case in the medical literature of a child with a c-spine injury who would have been classified as low risk using NEXUS
Laham et al (1994) Ped Neurosurg • Retrospective review of 268 children with apparent isolated HI • 2 high risk criteria = incapable of verbal communication (due to age or HI) and neck pain • Did x-rays in all kids • No abnormal x-rays in low risk group • 7.5% abnormal in high risk group • Authors concluded: In isolated HI with no neuro deficits, no x-rays needed if child can communicate and has no neck pain
What about the Canadian C-Spine Rules? • Have not been evaluated for use in patients < 16 years
Are there any consensus statements or guidelines? • American Association of Neurosurgeons (Guidelines committee of the section on disorders of the spine) [AANS] Management of Pediatric Cervical Spine and Spinal Cord Injuries Neurosurgery 2002;50(3) March supp • Guidelines based on available evidence and expert opinion
AANS Bottom Line:Children > 8 years • Evidence supports the use of NEXUS criteria: • Image if any one of: • Midline tenderness • Focal neurological deficit • Altered level of consciousness • Evidence of intoxication • Painful distracting injury
AANS Bottom Line: Children 8 years and under who are conversant • Although evidence is lacking, expert opinion supports the use of the NEXUS criteria • Given lack of evidence, and possible communication barriers in young children, it would be reasonable to consider imaging in high risk mechanisms: • high speed MVC • fall > 8 ft • axial load injury
What should we do with infants? • NEXUS – 88 patients < 2 yo – no injuries • NPTR – children < 2 yo : ~ 8 injuries per yr • No studies with large enough numbers to generate evidence-based practice recommendations • Have to go to expert opinion
AANS Bottom Line: Non-conversant Children • Advise obtaining images in all non-conversant children who have “experienced trauma” • Practically, this is not what’s done in most Canadian pediatric EDs
What should we do with infants? • See them quickly • Assess for altered LOC, neuro deficit, distracting injury • If no injury apparent, remove immobilization equipment in protected environment • Observe for spontaneous movement of neck • Most small children will “clinically clear” themselves
Clearing the Pediatric C-Spine PART 2: What films do I need?
General agreement that a lateral and AP c-spine film are necessary • The sensitivity of the lateral film alone in peds is comparable to the adult literature ~85%
Odontoid views? • Many authors have questioned the need • Swischuk surveyed 984 pediatric radiologists (432 responses) • Obtained reports of 46 pediatric fractures that were missed on lateral view and seen on odontoid view • Calculated a miss rate of 0.007 per year per radiologist
Odontoid views? • Buhs et al(2000) J Ped Surg - Retrospective review of all c-spine injuries in children< 16 yrs over 10 year period at 4 Detroit trauma centres • can’t r/o fracture with AP/lat alone
But odontoid views are hard to get in young children!!! • Consider: • 0-3 years: 50% of injuries are at C1 / C2 level • 4-12 years: 8% of injuries are at C1 / C2 level • Bottom line: If you are worried enough to image the c-spine, you need to get a good look at C1 / C2 ~need odontoid view or CT
Oblique views? • Ralston et al (2003) Ped Emerg Care: • Blinded retrospective review (8 year period) • Blunt trauma patients ≤16 yrs • AP/Lat + oblique views • N = 109
Oblique views? • All with normal AP/Lat had normal obliques (N = 78) If AP/Lat normal, obliques unlikely to add additional information • 4 obliques resulted in revision of impression: • 3 from equivocal to normal • 1 from equivocal to abnormal (final dx = no injury) May be of assistance in equivocal situation
Flexion-Extension views?Ralston et al (2001) Acad Emerg Med • Blinded retrospective review (6 year period) • Blunt trauma patients ≤16 yrs • AP/Lat (+ odont in 83%) + flex/ex views • N = 129 • 45 patients had initial AP/Lat read as normal – all had normal flex/ex views (no revision of impressions) If primary series is normal…flex/ex views do not add info • 84 patients had initial AP/Lat read as abnormal (including loss of lordosis -79 had revision of impression)
Flexion-Extension views? • Normal flex-ex views do not rule out an injury • If plain films worrisome, more sensitive modalities are warranted (CT +/- MRI) May consider flex-ex after to look for major instability • If the concern is significant pain despite normal plain films, quality of flex-ex view likely limited due to pain and they cannot be used to “rule out” an injury
To CT or not to CT…. • Routinely used in adults trauma patients to examine c-spine • There are significant concerns that exposing children to CT radiation may lead to an increased lifetime risk of cancer • Try to be much more selective with the use of CT in children • Limit scans to specific areas of interest
Indications for CT • Valuable for: • Defining anatomy in regions where an abnormality is suspected on plain film • Viewing regions not visualized on plain film • ie – skullbase to C3 in intubated patient • Remember: a large proportion of young children with c-spine injury will have an isolated ligamentous injury, a normal CT cannot be used to exclude a c-spine injury • CT can miss odontoid #
Evidence for early CT?Keenan et al (2001) AJR • Retrospective study of 63 kids • Head injury + C-spine plain films • 21/63 had early CT c-spine with initial head CT • 42/63 had plain films alone - often repeat attempts • Analyzed multiple patient factors + total radiation dose received in process of imaging c-spine • Found kids in high speed MVC with GCS <8 had same radiation with repeated plain films as with early CT (new generation, helical CT with recons)
How about MRI ??? • Keiper et al (1998) Neurorad • Retrospective case review • Children with hx of blunt c-spine trauma • Normal plain films + normal CT • One of: • Persistent or delayed neuro symptoms • Persistent significant neck pain • N = 52 • MRI abnormal in 16/52 (31%) • 4 went on to operative management