Introduction: Chance fractures, the horizontal splitting vertebral fractures caused by flexion distraction mechanism, are inherently unstable fractures. These fractures can land up with significant visceral injuries. There are most commonly seen at thoracolumbar junction or in lumbar spine due to their high mobility. These fractures are extremely rare in the thoracic spine due to the rigidity of thoracic spine rendered by attachment of ribs. Furthermore, the level of injury makes neurological complications even graver.
Case report: We present a case of a road traffic accident with right lower limb monoplegia. On careful examination, a thin transverse fracture line was noticed in D5 vertebral body, and magnetic resonance imaging revealed posterior ligamentous disruption extending in line with the transverse fracture line in D5 vertebral body which confirmed the diagnosis of a Chance fracture. Fracture was stabilized by pedicle screw fixation from D4 to D7 level, and decompression was done at D5 level. By the end of 7 months, patient regained Grade 4 power in the right hip and knee joints, with Grade 5 power in the right ankle and great toe.
Conclusion: Chance fractures in thoracic region are extremely rare. A clinician should have a high index of suspicion as these fractures can be notorious when it comes to presentation on plain X-ray. These being inherently unstable fractures, posterior instrumented stabilization with decompression in patients with neurodeficit gives good results.
Keywords: Chance fracture; flexion distraction injury; monoplegia; seat belt injury.