Will I be nude during lumbar disc surgery?

Yes. For operations of the low back you are nude but do not worry all areas of the body except the ares of surgery is covered with drapes and modesty of patients is always taken into account.
Yes. Yes, but after bring properly positioned, you will be covered by the surgical drapes. The OR staff make every effort to keep you covered as much as possible.
Yes but covered most. You will be naked but nursing will keep you covered over most of your body while being placed under anesthesia & positioned on or table. Once positioned, you will stay fairly well covered except for the lower back that will be washed & then you will be further covered by surgical drapes except for the exact area of the incision. The reason is not modesty but warmth as it reduces infection rates!