They come in the front door of the surgery suite, they have surgery with some kind of anesthetic, they go to the PACU alive and breathing, they're discharged from PACU and... disappear from the face of the earth. Unless something goes majorly wrong.
So how did that nerve block work? Up til now you mostly only know about the things that went wrong. But now there's an ongoing study of femoral and sciatic blocks that can give you feedback on what went right (and wrong).
Already there appear to be some surprises. Length of time for blocks to set up. How long they last. Difference between concentrations of local anesthetics and the effect of presence or absence of epinephrine in the local.
As more data is collected more may become clear about what you are doing and how it can be improved if, at all.