Is the "numbing" part of the lumbar sympathetic block painful? Should I be able to tolerate w/o sedation. I'm a student, very busy, no being in daze-

It can be painful. Would recommend the use of short acting sedating agents that do not have lingering sedation effect after the surgery is complete. Unwise to proceed with the procedure w/o sedation for it can be a painful procedure.
Not very painful. The procedure involves inserting a needle through skin and deeper tissues. So, there is some pain involved. However, we may numb the skin and deeper tissues with a local anesthetic using a very thin needle before inserting the actual block needle. Most of the patients also receive intravenous sedation that makes the procedure easier to tolerate.