A vascular occlusion device deployment system for placing an occlusion device at a preselected site within the vasculature of a patient. The deployment system employing a pusher having a lumen with an opening at the distal end of the pusher. A vascular occlusion device is connected to the distal end of the pusher by a portion that is removeably disposed within the opening. The portion of the occlusion device is forced out of the opening by an expandable reaction chamber, thereby deploying the occlusion device. In one embodiment a vascular occlusion deployment system comprises: a deployment unit comprising a pusher having a proximal end portion and a distal end portion with a distal opening, the pusher including an inner wall defining a cavity proximal of said distal end portion, the cavity having a distal wall opening a vascular occlusion device having a protruding portion sized and shaped to be removeably disposed within the distal opening a first reactant and a second reactant located within the cavity proximal the distal wall of the cavity and a frangible wall separating the first and second reactants wherein said frangible wall is capable of being breached to allow said first reactant and second reactant to mix forming a product that expands in the direction of the distal opening, said expanding product applying a force to the distal wall and the protruding portion of the vascular occlusion device so that the protruding portion is removed from the distal opening, thereby deploying the vascular occlusion device and an element for breaching the frangible wall.
