Medical devices for fluid delivery and methods of use and manufacture

An intravascular apparatus, comprising:

• an inflatable balloon having an inflated cylindrical configuration;
• an expandable infusion scaffold comprising at least first and second expandable infusion spines, each of the at least first and second infusion spines defining a lumen therein and each including two or more spaced apart radial openings therethrough,
• wherein the expandable infusion scaffold is adapted and positioned about the inflatable balloon such that inflation of the balloon causes the scaffold to radially expand, the at least first and second infusion spines extending about an outer cylindrical surface of the inflatable balloon when the inflatable balloon is in an inflated state;
• and
• a plurality of movable needles assemblies, each one of the plurality of movable assemblies disposed in one of the at least first and second expandable infusion spines and movable within and relative to the infusion spine, each of the plurality of movable assemblies comprising
• a rail that includes a rail lumen, a plurality of needles, and one or more fluid delivery lumens within the rail lumen that are in fluid communication with the plurality of needles,
• wherein the plurality of needles are coupled to the rail such that movement of the rail within the corresponding infusion spine moves the plurality of the needles as a group relative to the infusion spine between undeployed configurations in which each of the plurality of needles are housed within the infusion spine and deployed configurations in which each of the plurality of needles extends generally radially out of one of the radial openings in the infusion spine for delivery of an agent into a wall of a target vessel,
• wherein each rail includes one or more first alignment members that comprises a rail slot, and the corresponding spine in which the rail is disposed includes one or more second alignment members, the one or more first alignment members that comprises a rail slot sized, positioned, and configured to interface with the one or more second alignment members to maintain circumferential alignment of the corresponding plurality of needles and the plurality of radial openings as the rail is axially moved within the spine and thereby facilitates deployment of the plurality of needles out of the plurality of radial openings.