Chronic subdural hematoma associated with arachnoid cyst. Two case histories with pathological observations.

Arachnoid cysts are well known to induce chronic subdural hematoma (CSDH) after head injury. However, histological observations of the arachnoid cyst and hematoma membrane have only been rarely described. An 8-year-old boy and a 3-year-old boy presented with CSDH associated with arachnoid cyst. Surgical removal of the hematoma and biopsy of the hematoma membrane and cyst wall were performed. Clinical courses were good and without recurrence more than 1.5 years after surgery. Histological examination suggested that the cysts did not contribute to hematoma development. Pediatric hematoma membranes, similar to adult hematoma membranes, are key in the growth of CSDH. Therefore, simple hematoma evacuation is adequate as a first operation for CSDH associated with arachnoid cyst.

[Vertebral arteriovenous fistula as a complication of atlantoaxial transarticular screw fixation--case report].

We report a rare case of a vertebral arteriovenous fistula that developed as a complication of atlantoaxial transarticular screw fixation. The patient was a 44-year-old male with a history of juvenile rheumatoid arthritis. He had undergone an atlantoaxial transarticular screw fixation for an atlantoaxial dislocation. At 2 months after the surgery, he complained of right-side tinnitus. A selective left vertebral angiography showed a high-flow arteriovenous fistula of the right V2 segment and occulusion of the right vertebral artery at the level of the C3 vertebral body. Endovascular embolization of the arteriovenous fistula was successfully performed using detachable coils. No deficits were observed after the treatment, and the tinnitus disappeared completely. Endovascular coil embolization is currently an effective and safe treatment for the vertebral arteriovenous fistula.