I would say (I'm young btw) out of about 10 facet cysts I tried to aspirate despite good needle placement (confirmed of course with good IA spread of small amount of contrast) I have successfully aspirated fluid that was straw colored, not clear, about 3 times.
I just had a case (last week) with a rather distraught female who had "chronic" back pain but was seeing me for "disabling" leg pain acute onset 3 weeks, new MRI showed a very small facet cyst from anterior superior facet at L4-5. I told her I would try and help with her leg pain as that is why she came to see me.
I did an aspiration and got back about 1cc of very straw colored fluid (did not inject steroid) and then followed with an L5 TFESI
Just saw back in clinic, she looked angry and I asked if the injection helped, she abruptly told me NO!
I asked where her pain was and she told me "My leg pain has completely resolved but I still have my chronic back pain"
The people we deal with on a daily basis.....I question if my motor will stay gassed and lubed for the next 30 years