Methods and devices for treating tissue

An epidural injection system comprising:

• a needle cannula having a sharp tip at a far end of the needle cannula, where the sharp tip is adapted to penetrate tissue, and a needle lumen extending through needle cannula;
• an injection tubing having a distal portion having a distal end, a proximal portion, and an injection lumen extending between the distal portion and the proximal portion, where at least the distal portion is flexible and where the injection lumen exits the injection tubing at an injection port, where the injection tubing is moveable within die needle lumen and limited to extend out of the needle lumen by a fixed distance;
• a sliding member affixed to the injection tube such that a sliding movement of the injection tubing limits a stroke of the injection tubing to the fixed distance such that when the injection tubing is in the proximal position, the distal portion is within the needle cannula and when the injection tubing advances to the deployed position, the distal portion or the injection tubing extends out of the far end of the needle cannula;
• and
• a connector on the proximal portion of the injection tube for coupling the injection tube to a fluid source.