You should post your SIJ RFA technique for the group as it is different from standard.
But sounds like it works for your patients and with less post procedural pain.
Needle insertion caudal to get cannulae tips parallel to os in nal placement.
I have a cephalad tilt to the II and oblique as necessary to see S1, S2 and S3
posterior foramina and groove the nerve exits in laterally. From anatomical
pictures the branching of the of the nerves is less medially and inferiorly for S1,
midline S2 and superior S3. This is where I put the tips of the needles. Snug
against OS ventral, tip firmly against superior wall of the groove for S3 and
usually S2. S1 I am inferior for placement.
Go to lateral. Often looks a bit different than the below images.
The sacrum is triangle in lateral view and usually S2 and S3 are lower on the
slope so your needle appears to be almost in sacral canal. If I see this at SI I am
too ventral and not a safe placement. This allows me to place more medial
safely in AP for S1 which gets me closer to where it branchs. I believe S1 is
largest and provides most innervation to joint so I am particular about
placement.
As far as lesion size a 22g lesion is 6x10 versus 7.5x12mm for 18g.