Embolization of cerebral arteriovenous malformations with cellulose acetate polymer: A clinical, radiological, and histological study

OBJECTIVE: A cellulose acetate polymer (CAP) solution was hypothesized to b e useful for the embolization of arteriovenous malformations (AVMs). To inv estigate this possibility, we analyzed the clinical, radiological, and hist ological results of patients with AVMs embolized by using a CAP solution. METHODS: We reviewed the cases of 11 patients with AVMs treated by emboliza tion before surgical resection. We used two types of CAP solutions, CAP-M a nd CAP-L, which are mixtures of 250 mg of solid CAP and 1800 or 2250 mg of bismuth trioxide dissolved in 5.5 or 7.0 mi of dimethyl sulfoxide, respecti vely. After the embolization procedure, percent reduction of the nidus volu me was measured, and thereafter, the clinical course and computed tomograph ic scans and/or magnetic resonance imaging scans were evaluated. All patien ts underwent surgical resection 1 to 51 days after embolization. Resected s pecimens were stained for light microscopic examination. RESULTS: Thirty-nine feeding vessels were embolized. The reduction rate of the nidus volume ranged from 20% to nearly 100%. Transient and persistent i schemic deficits occurred in three patients and one patient, respectively, and there were no hemorrhagic complications. All AVMs but one were complete ly resected by surgery. The embolized AVMs were soft enough to be easily cu t and retracted. The histological examinations disclosed no or mild inflamm atory reactions within 2 weeks after embolization. The internal elastic lam ina was preserved in every case. Recanalization through the cast of the CAP mass was not observed until 51 days after embolization. CONCLUSION: CAP solution is a safe and useful embolic agent for AVMs.