A 6 yo girl arrives to the ED via ambulance after she was involved in a motor vehicle crash. EMS reports that she restrained in the middle of the backseat of the vehicle by a lap belt. Driving too quickly in the rain, the driver lost control of the vehicle and collided with a tree just off the road at approximately 55 mph. The patient has had reported loss of consciousness. The patient is currently complaining of abdominal pain and back pain. The patient has the following finding on exam:
Trauma labs and imaging are ordered. A fracture is reported on imaging of the lumbar spine Which of the following is true about your suspected diagnosis?
Answers:
A. Concurrent intra-abdominal injuries are uncommon
B. Fracture occurs most commonly in the lower lumbar spine
C. Fracture occurs due to axial loading
D. Treatment is with casting or TLSO bracing if there is purely osseous injury
This vignette tests recognition of the classic pediatric “seat‑belt” or Chance fracture. We want you to link the mechanism (lap‑belt flexion–distraction) to the pattern of bony and soft‑tissue injury. This is a common boards gotcha because the presentation is subtle and because examinees often confuse mechanism, typical level, and management.
| Option | What It Tests / Implies | Why It’s Wrong Here |
|---|---|---|
| Concurrent intra‑abdominal injuries are uncommon | Tests knowledge of associated injuries with lap‑belt/Chance fractures. | Wrong: intra‑abdominal injuries (small bowel, mesenteric) are common — reported up to ~50% in older series — so they are not uncommon. |
| Fracture occurs most commonly in the lower lumbar spine | Tests knowledge of typical level of injury. | Wrong: Chance fractures more commonly occur at the thoracolumbar junction (eg L1), not the lowest lumbar levels. |
| Fracture occurs due to axial loading | Tests understanding of injury mechanism. | Wrong: Chance fractures are flexion‑distraction injuries from lap‑belt fulcrum, not pure axial compression (which causes burst/compression fractures). |
| Treatment is with casting or TLSO bracing if there is purely osseous injury | Tests management decision‑making based on stability and soft‑tissue integrity. | Correct: If the injury is purely osseous, neurologically intact, and ligaments are intact, conservative management with casting or TLSO is appropriate. |
A Chance fracture = flexion‑distraction at the lap belt; check for intra‑abdominal injury and ligamentous disruption; MRI if concern for soft‑tissue injury.
This question tests differential recall of mechanism language while embedding a clinically relevant association (seat‑belt sign + abdominal pain). The trap is the seemingly plausible alternative mechanisms and levels (axial loading, lower lumbar), which many clinicians overapply from other crash injuries. The vignette primes you to think intra‑abdominal injury but the tested single best answer is about spine management — recognize which fact is being asked.
(Topics: identification of Chance fracture mechanism/level, associated intra‑abdominal injury, imaging and management decisions; pediatric ED context)
A 7‑year‑old restrained child involved in a frontal MVC presents with a horizontal abrasion (seat‑belt sign) across the abdomen and midline back pain. CT shows a transverse fracture through the posterior elements and across the vertebral body at T12–L1 without canal compromise. Neurologic exam is normal. The next best step in management is:
A. External fixation in the operating room
B. TLSO brace and bowel evaluation
C. High‑dose IV steroids and immediate fusion
D. Emergent laminectomy and decompression
E. Bed rest only, no brace
A 9‑year‑old in a MVC was restrained with only a lap belt. He has abdominal tenderness and an L1 fracture suspicious for flexion‑distraction. Which imaging is most useful to evaluate for an associated ligamentous injury of the spine?
A. Plain radiographs only
B. CT lumbar spine only
C. Ultrasound of the abdomen and spine
D. MRI of the spine
E. Repeat CT in 24 hours
In pediatric patients with suspected Chance fracture, the most commonly injured intra‑abdominal organ is:
A. Liver
B. Small bowel/mesentery
C. Spleen
D. Kidney
E. Pancreas
A 6‑year‑old with a lap‑belt sign has back pain. Imaging demonstrates a Chance fracture with posterior element distraction and an associated posterior ligamentous complex disruption on MRI. Neurologic exam is intact. Best next step:
A. TLSO brace and observation only
B. Consult spine surgery for operative stabilization
C. Manage non‑operatively but avoid MRI (redundant)
D. Outpatient follow‑up in 2 weeks with no immobilization
E. Epidural steroid injection and early mobilization
A 10‑year‑old restrained only by a lap belt collides with a guardrail. He is neurologically intact but has persistent abdominal pain and a thoracolumbar Chance fracture. Which statement is true about long‑term considerations?
A. Chance fractures always heal without deformity with casting.
B. Untreated ligamentous instability can lead to progressive kyphosis and chronic pain.
C. Pediatric spines are immune to post‑traumatic deformity due to growth potential.
D. All Chance fractures require immediate fusion to prevent deformity.
E. Return to sports is safe within 2 weeks if neurologic exam is normal.
Compare management and imaging strategies for a suspected Chance fracture in a 6‑year‑old lap‑belted child with isolated back pain versus one with abdominal tenderness and hemodynamic instability. How does the presence of abdominal signs change your priorities and diagnostic pathway?
This question appears in Med-Challenger Pediatric Emergency Medicine 3rd Edition Exam Review with CME
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