[Posterior fossa hemorrhage 11 years after the use of silastic dural substitute: case report].

: A case of posterior fossa hemorrhage is reported. The hemorrhage occurred 11 years after posterior fossa craniotomy with closure using a graft of silastic dural substitute. This 14 year-old girl underwent suboccipital craniotomy at the age of 3 years because of traumatic posterior fossa hemorrhage. The dura mater was repaired with a piece of dural substitute. Eleven years later, she developed severe headache and vomiting. Computerized tomography scanning revealed a high density area in the right posterior fossa. At exploration, a fresh clot was evacuated between the dural graft and the fibrous scar tissue. The resected fibrous scar tissue was 1cm thick, and was adhering to the duro glial scar tissue. Her postoperative course was uneventful, and she was discharged 2 weeks after surgery. Microscopic examination of the fibrous scar tissue revealed an outer layer of loose connective tissue with numerous capillaries. The inner layer consisted of dense connective tissue. It was speculated that fragile capillaries of fibrous scar tissue caused this hemorrhage. Surgeons should not forget this complication although silastic dural substitute is less used than it used to be.