The proposed device for the occlusion of brain vessels comprises an occlusive bulb of an elastic material. Its thicker head portion accommodates a metal plug, while the tail portion contains a valve made of the material of the bulb itself, through which the tip of a catheter is introduced. The pear-shaped...http://www.google.co.uk/patents/US4282875?utm_source=gb-gplus-sharePatent US4282875 - Occlusive device
