I wanted to have both done simultaneously. My thinking was that rehab takes a year or more, and I wanted to only go through that once. My surgeon advised that there is greater total risk from 1 single, longer operation than 2 separate operations. The off the cuff explanation was that if you assign an arbitrary risk value of 1 to a single-side resurf operation and then have the other side done a month or so later, the total risk is 2. But for a single operation, simultaneous resurf, the risk would be more like 2.5. Apparently there is greater risk of needing blood transfusion, for e.g.. After saying that, the doctor added that he had done many simultaneous bilat and all had turned out fine, and all patients had obviously been very happy.
I followed the surgeons advice and had the operations 5 weeks apart. So far, so good, and I am very happy to think that my work at rehab will soon be done, and that I won't have to go through it again for "the other side."
I think a lot has to do with the types of activities you want to return to and the schedule you would like for recovery.
Good luck,
-Dirk
Bilat, Dr. Ball, DePuy ASR, 02/08 and 03/08.