Hello 'Chris Baltimore', thanks for your question. The answer to your question depends on multiple factors, which ultimately rests upon weighing the benefits VS risks of a procedure. Any surgery has potential risks and complications, and in the arena of cosmetic surgery it becomes tricky as patients do NOT HAVE to have surgery for a particular disease or traumatic injury. It is all elective, and the patients need to determine for themselves how much of an improvement in their quality of living will the cosmetic surgery offer them. That being said, as long as you are healthy without significant medical problems, an eight hour procedure under anesthesia would still be considered within safe limits. Longer than this however will lead to gradual increased risks, such as blood clots, cardiovascular stresses, and respiratory issues. Surgeries that last over 24hrs have been described and patients have done OK afterwards, but these are for medically necessary procedures. Hope that helps!
-Dr.92660