To assess the effect and mechanism of early cranioplasty for the treatment of intractable subdural effusion after large decompressive craniotomy for traumatic brain injury.

Twenty traumatic brain injury patients with subdural effusion after decompression craniotomy were selected from Neurosurgery Department of 251 Hospital of PLA from January 2014 to January 2019. All these patients had received subcutaneous or skull burr hole drainage, local pressure, lumbar drainage or cistern dissection, which gained little beneficial effect. They received cranioplasty 4-6 weeks after decompressive craniotomy. The alteration of subdural effusion was observed to assess the effect of early cranioplasty.

Local wound infection occurred in 2 patients after operation and recovered after active dressing change and antibiotics treatment; Subdural effusion was not significantly reduced in 5 patients revealed from the 1^st month CT reexamine after operation, and gradually decreased and disappeared revealed from the 3^nd and 6^th month follow-up after the operation; the rest patients achieved good results, neurological dysfunction recovered to varying degrees, and no recurrence of subdural effusion was observed during follow-up.

Early cranioplasty can effectively treated intractable subdural effusion.