Sinking skin flap syndrome is a rare and potentially fatal complication of a decompressive craniectomy. It occurs when atmospheric pressure exceeds intracranial pressure at the craniectomy defect.

This results in displacement of the brain across various intracranial boundaries. This may result in subfalcine and/or transtentorial herniation.

Clinical findings may range from asymptomatic to a monosymptomatic state to an acute neurological deterioration. Radiological findings here are typical.