Appropriate interval between embolization and surgery in patients with meningioma.

BACKGROUND AND PURPOSE The best time for surgery after embolization of meningiomas remains unclear. We used the tumor-softening effect of embolization to determine this time. METHODS Forty-two patients with intracranial meningiomas that received more than 50% of their blood supply from the external carotid artery underwent embolization before surgery. The interval between embolization and surgery and the tumor consistency at the time of surgery were recorded. The interval between embolization and surgery was divided into 3-day segments, and an average tumor consistency score was obtained in segments. Patients were assigned to two groups: group 1 underwent surgery on a specified day after embolization; group 2 underwent surgery at a later date. We compared tumor consistency, blood loss, length of hospitalization, surgical resection time, Simpson grade at surgery, and complication rate in both groups. RESULTS On the polynomial regression curve, greatest tumor softening occurred 7-9 days after embolization. When the postembolization interval exceeded 10 days, no further softening occurred. Compared with group 1 patients, group 2 patients did not have an increased blood loss, a longer hospitalization, or a higher complication rate. In group 2, the surgical procedure required less time, and the Simpson grades were lower. CONCLUSION In meningiomas that receive more than 50% of their blood supply from the external carotid artery, the optimal interval between embolization and surgery is 7-9 days. This interval allows the greatest degree of tumor softening, which makes it possible to remove the tumor more safely and easily.