Doing great....board meetings, expanding practice, research, and my teenage kids keeping me busy...
I don't always get in to L5S1...there were about 3 or 4 cases over the past 10 years that I could not enter, because of either disc space autofusion or vertebral body osteophytes that were pronounced and bilateral.
Tricks I use for more difficult access:
1. Use up to a 60 deg curve on the distal cm of the needle and twirl the needle helicopter style on entry, contact the SAP (aim for the base, but sometimes the iliac crest causes a more cephalad contact), then switch to lateral fluoro view for entry. The repositioning of the needle is very easy within the vertebrae with such a curve by retracting the needle within the disc, reversing the curve direction, then readvancing
2. With a high iliac crest, with the fluoro in a 30 deg oblique to the sagittal plane, enter over the top of the crest regardless of whether you can see the disc, then change views to the traditional window, and advance onto the SAP, then into the disc
3. When there is severe osteoporosis or the anatomy is mush on oblique fluoroscopy, initially place a guide needle onto the lateral border of the SAP in a non-oblique rotation but with a cephalo-caudad beam angulation through the disc. Then rotate to the oblique 30 deg, and use the tip of the first needle as a target.
4. Go to the opposite side if there are overlying osteophytes or fusion on one side....sometimes the contralateral side is open
5. If on initial fluoro exam through the disc, it appears to be closed, try having the patient change positions by laterally flexing at the waist. Sometimes this opens up one side.
6. If you are dead set on getting in, sometimes you can drill your way into through small osteophytes with the needle tip.
7. Another means of desperate access includes transdiscal in the midline with a needle tip curved 20-25 deg (the curve is necessary due to the necessary cephalad tragectory through the interlaminar window that is approximately 25 degrees angled to the disc. The needle curve can then be used to access the disc and curve to the anatomical center of the nucleus of L5S1 which of course lies at the junction between the anterior 2/3 and posterior 1/3 of the disc for L5S1 due to the very thickened anterior annulus fibrosis)
8. Finally, if you are brave, you can use the intracanal, extradural approach that bypasses the dura laterally. This works best with the patient in the lateral position, but the fluoroscopy angles are use are difficult. Enter the interlaminar window starting over the midline interspinous ligament and aim for the edge of the inferior lamina. Once the lamina is contacted, advance the needle around the dura (that is now partially reduced in lateral diamter due to the lateral position) until the disc is contacted, then on into the center of the disc. During my translaminar endoscopic discectomies, I use continuous irrigation after dissection of a ligamentum flavum window, and the irrigation pushes the dura medially. The same may be true in discography if a second tuohy needle were placed in the lateral epidural space with continuous irrigation.
Hope this was helpful
