Often antibiotics don't work in the upper sinuses, due to the low blood supply, and the fact that sinus infections work differently than other tissue infections. This is an often effective technique that removes the infected mucus in the upper sinuses, avoiding surgery.
http://www.medhelp.org/user_journals/show/2322
The Flip-Turn Sinus Flush is mildly risky, because you have to bend over to do it, preferably in a shower, but you can also do it outside on soft ground, or you can kneel down and lean over a bathtub, or perhaps a plastic basin or tub, with the shower running for steam.