Paradoxical Brain Herniation after Cranioplasty: Secondary Sunken Flap Syndrome

Decompressive craniectomy is a life-saving procedure done for innumerable etiologies. Though, not a technically demanding procedure, it has its own complications. Among many, sinking flap syndrome or syndrome of the trephined or paradoxical herniation of brain is frequently underestimated. It results from the pressure difference between the atmospheric pressure and the intracranial pressure causing the brain to shift inward at the craniectomy site. This can present with either nonspecific symptoms leading to delay in diagnosis or acute neurological deterioration, memory disturbances, weakness, confusion, lethargy, and sometimes death if not treated. Cranioplasty is a time validated procedure used to treat paradoxical brain herniation with good and early neurological recovery. We, here in, are going to describe a case report in which the paradoxical herniation occurred after cranioplasty which has not been described in literature.