Implantable therapy systems are disclosed for the local and controlled delivery of a biologically active factor to the brain, spinal cord and other target regions of a subject suffering from a debilitating condition. The method of the invention involves surgically exposing an insertion site, generally located above a predetermined treatment site (12), in a patient. A cannula (20), having an obturator (30) or dilator (104) positioned therein, is inserted at the insertion site, defining a pathway to the treatment site. In some instances, the cannula can be inserted along the path of a guidewire (102) previously positioned at the treatment site. The cannula (20) is preferably a low friction polymeric material such as polytetrafluoroethylene. The cannula (20) generally has an open proximal end for receiving the obturator (30) or dilator (104), and an open distal end, preferably a tapered end, for delivery of neurologically active factors to the treatment site (12). The obturator (30) is then removed from the cannula (20), and a biocompatible tethered vehicle (40) containing a biologically active material is inserted into the cannula along the passageway. A pusher can be inserted within the cannula, behind the vehicle (40), to position the proximal end of the vehicle at the distal end of the cannula (20b). Once the vehicle (40) is positioned near the distal end of the cannula (20), the cannula is removed from the passageway, followed by the pusher, leaving the vehicle (40) positioned at the treatment site (12).