A vascular occlusion device deployment system for placing an occlusion device at a preselected site within the vasculature of a patient. The deployment system employs a pusher including a gripper located at the distal end of the pusher to releasably retain a vascular occlusion device. The gripper is expanded under the force of a collapsible chemical reaction chamber so that the gripper releases the vascular occlusion device, thereby deploying the vascular occlusion device.
