Contusion expansion or a new intracranial hematoma could develop after decompressive craniectomy contralateral or remote to the decompressed hemisphere. This complication may occur because of a reduction or loss of the tamponade effect and may develop early after decompression. Appropriate management based on close monitoring and early detection is the key to proper management.
The mechanism of postoperative epilepsy is still not fully understood, but graded increases in hyperexcitability and a reduced epileptogenic threshold have been suggested to be potential causes of seizure. Prophylactic antiepileptics may prevent postoperative epilepsy.
The mechanism of external cerebral herniation has been attributed to brain edema. External cerebral herniation may cause cortical vein compression and cause cortical laceration resulting in venous infarction of herniated brain tissue and cortical damage. Large craniectomies with augmentative duraplasty allow the brain to expand outward without constriction, and thus, minimize the risk of venous infarction.