Using pre-operative pain medications would not make you wake up during the surgery but Duragesic will block the effects of most other pain killers that you might need during and after surgery. This includes all opiates which are most commonly prescribed to manage post operative pain. That is the reason the patch is usually stopped pre-op, but the Fentanyl would probably be continued as it doesn't do the same thing.

May I suggest you ask our resident pharmacy expert, mrsD? I'm sure she'll be able to answer better than I can.