Definitely a learning curve on this one to stay posterior enough, especially when sometimes handling hard bone, tall medial iliac crest, wide and narrow s1 vert body etc.
Some excellent prior threads on this, most of what I learned was via posts by rolotomassi
Here is cut and pasted from my notes file put together over the 4 years of doing this, just shy of 200 cases:
S1:
- Ferguson/head tilt to square sep,
- If oblique at 30-35 still has crest in way - tilt even more to head to get access.
- can doc a bit laterally to med-pedicle, walk medially til hit sap in deepest part of groove
- If placement overall very difficult at S1, and started wide angle, le 40+, can advanced ICA much further into vb then much shorter distance for CCA needed.
- Use bevel.
- make sure final entry into VB is close to medial border pedicle..... if too far lateral before J, leaves long path to get to midline.
- can also consider going through iliac crest if its too high/medial
Not specific to this level, but if hard bone, even if you have a big angle, I would still recommend keeping the J retracted, “distal scallop” on Gen 3. it is always a better problem to be too posterior, much much easier to fix, than too anterior. Their generation three equipt is a really nice step up in multiple ways, but all the tricks needed with the earlier generations are still sometimes needed with hard bone or other unfavorable anatomy.