Depends on what you are trying to accomplish....
With 22ga needles I use a last 1cm tip bend with a hemostat. For transforaminal lumbar blocks, usually a 10 deg bend will do. For z-joint injections lumbar 10 deg, thoracic z-joints I use 20deg, and around 15 for cervical IA z-joint injections, although I usually do medial branch blocks instead. For lumbar discography, I use 20 deg for L3-4 and L4-5, up to 45 deg for L5-S1, and 10 deg for L1-2 and L2-3. Cervical discography 10 deg. For caudal epidurals I use a 20 deg bend over the last 2 cm except for the morbidly obese, in which I may use up to a 40 deg bend over the last 1cm. For transcaudal lateral recess blocks at L5S1, I use a double curve of 20 deg at the tip and another 10-15 deg over the distal 10cm of the blunt 203mm needle in order to keep the tip in the anterior epidural space. For far lateral approach transforaminal epidural and lateral recess blocks, I use a 20 deg curve at the tip and a straight shaft for the 20 ga blunt needles. For an interlaminar approach lateral recess block, I use a 20 deg curve at the blunt needle tip and approach from the contralateral side entering the ligamentum flavum on just to the contralateral side of the needle entry or alternatively use a 22ga spinal needle with a 30 deg angle at the tip to target the most medial border of the lamina at the disc level, then walk under the lamina and laterally. RF, I use 15deg curves at the tip..
All curves are with the bevel, to accentuate the natural curve the needle would take due to the bevel inclination.
It is rare for me to use a straight needle....
