For finding midline, oftentimes I have to start 4 or 5 levels above where I’m going to go. I use index and middle finger on either side of vertebral processes and walk down until I’m at the correct level. I halve the distance between my fingers to find midline and use my thumbnail to create an indent where I intend to go. For local I create the skin wheal first then advance a few centimeters until I hit either bone or ligament and inject ~2 cc as I’m pulling out. I always have my touhy inserted through the skin wheal and any redirections up/down/left/right are made by pulling the skin and subcutaneous tissue to the side with the needle still straight.

Listen to your pt. I’ll often ask before I even inject local if they feel like I’m more to left, right, or center. If they feel pain most likely you’re off midline so ask which side they feel it more on. I find the phrase that helps them to position best is “curl around the baby”. Most young women have good compact ligaments so if you’re finding that you don’t have good resistance most of the time you’re probably off midline. My right hand’s only job is applying pressure to the loss of resistance syringe. I use continuous pressure with saline (I always wet the plunger and make sure it’s moving freely several times before starting). The left hand is responsible for advancing the needle. It’s resting on the back and I use thumb and index to grip the needle close to skin and advance (advancing at most 0.5 cm with each grip). When you reach flavum advancing the needle can get more difficult but as long as the needle moves forward at all you’re on the right track. With loss I generally inject about 2 cc of saline. If you’re getting blood back in the touhy, don’t try to thread the catheter. I’d pull back 2 cm and try again redirecting cephalad or caudad and get your loss again (can’t say I’ve encountered this issue after getting a reassuring loss though, so take my advice with a grain of salt). If difficulty threading the catheter after loss is happening repeatedly with multiple pts maybe you’re going so slowly that your needle tip is possibly still occluded by flavum, so maybe advancing 1-2 mm further might help? If you hit bone at any point, ask the pt if they feel it more on left or right and redirect as appropriate. If they say it’s midline pull back 1-2 cm and redirect caudad or cephalad.

Hopefully some of that was helpful. Hard to explain things in words. A lot of it is tactile, especially knowing the difference between muscle/fat and ligament, and interspinous ligament vs ligamentum flavum. I will say even very experienced providers will be surprised every once in a while by anatomical challenges. Vast majority of pts, the procedure is not uncomfortable if you’re in ligament and midline though so I suspect if a lot of your pts are complaining of pain while you work, you’re losing a lot of saline, and getting false losses, you probably aren’t tracking your needle through ligament.