For implanting a therapeutic element, this needle assembly comprises a cannula having a sharpened distal end, a line of elements in the cannula extending rearward from the distal end. Yieldable positioner positions the element more proximate the distal end a predetermined distance from the distal end. The positioner may be in various forms including an end plug, a tab in the cannula and a distortion of the wall of the cannula. A stylet is reciprocable in the cannula and engages the end of the line of elements more remote from the distal end of the cannula.
