I have had 3 sets of injections in the S1 & L5 before I had to have surgery. The Hospital will put you in a room and ask you to change into a gown, then you lay on the bed and they come in and start an IV for the sedation meds.
When they are ready for you, they will wheel you into a room with a large overhead Xray machine and you will be asked to move over on the table and lay on your stomach, a nurse will be up by your head and the Doc will be adjusting the Xray machine.
Then you are given a light sedation and the Doc tells you everything he or she is doing, it doesn't take very long at all.
Then you will go to a room to rest for a hour and go home.
You will be very sore and possibly in more pain than you are right now for about 2-3 days, then the meds kick in.
I had a problem with my first one, and it's not likely to happen, but just in case: When they started my IV for my first set of injections, I was very scared and crying, I heard the nurse say she was afraid to flush the IV (if you hear those words tell them if in doubt MOVE IT!)I told them that the other 2 times and they did without a problem, anyway, when the Doc gave the OK for the sedation my vein blew, so I went through the first one with no sedation. However, they were very nice and tried to give me more hoping it would be absorbed, the Doc told me everything she was doing step by step, the only thing I felt was a tiny sting to numb the area and 10 minutes later she said she was done. There was nothing to be afraid of after all.
Yes, if you have too many they can damage the area, but your not allowed more than 3 a year to help prevent this.
The Best of luck to you,