The invention provides surgical needles with a porous
distal portion from which a liquid injectate will
weep or ooze multidirectionally under
injection pressure while the porous
distal portion of the needle is inserted into a
body surface. The porous
distal portion of the needle can be fabricated from a
porous carbon,
metal,
ceramic or
polymer and preferably has a decreasing gradient of impedance to fluid flowing to the point of the needle to compensate for the falling off of
injection pressure as fluid moves towards the point, thereby ensuring uniform weeping of the injectate along the injection course. The needle is adapted for attachment to a
catheter or
syringe. In another embodiment, a surgical assemblage is provided wherein a porous distal portion having similar fluid flow characteristics is located along the distal end of a
catheter, and a needle point is attached to the distal end of the
catheter (e.g., a steerable catheter) for piercing tissue. A guidance catheter can be used to direct the invention devices to a remote internal
injection site. The invention devices and methods can be used to inject fluids (including those containing nucleic acids for
gene therapy) into interior body walls or tissue, such as a
beating heart, without substantial loss of fluid and without substantial damage to tissue caused by injectate.