Cerebellar contusion associated with type I Chiari malformation following supratentorial head trauma: case report.

Acute presentation of Type I Chiari malformation in children is distinctly rare. An 11 year old male suffered a trauma to the right temporal-parietal region in a tobogganing accident resulting in an open depressed skull fracture. Radiographic evaluation included a Computed Tomographic scan which also demonstrated a significant cerebellar contusion and the presence of subarachnoid hemorrhage in the region of craniovertebral junction. Magnetic Resonance imaging revealed an underlying Type I Chiari malformation. Somatosensory evoked responses shortly following the injury demonstrated slowing of conduction across the lower brainstem. The open depressed fracture was debrided and elevated. Subsequent observation resulted in slow improvement in neurological function. A followup somatosensory evoked potential study performed 21 days following the accident showed improvement in conduction across the craniovertebral junction. The tonsillar ectopia associated with Type I Chiari malformation may predispose to cerebellar, upper spinal and brainstem injury following supratentorial trauma.