Dr. Elias Chua, M.D

The best way to view what you should do prior to undergoing anesthesia is this. You need to be in your best physical condition (medically optimized) because anesthesia and surgery can potentially be an extreme stress on your body. Though surgery usually goes just fine, if an unforeseen complication results in extreme measures to get you through the procedure, it is absolutely in your best interest to be physically optimized. Even the most benign procedures can lead to complications so don't get plastered the night before but a glass of wine or a beer is probably fine.

Greatest variable in the amount of discomfort is the provider’s experience and the patient’s anatomy. A spinal and an epidural are very similar procedures placed most likely in the same location. A spinal goes about 1 cm deeper as it needs to be placed into the intrathecal space, vs. the epidural space. The spinal needle is usually much thinner than an epidural needle. If you understand the measure of Gauges with regard to needle diameter, a spinal needle for a spinal anesthetic is typically a 25 Ga and sometimes a 22 Ga needle. The epidural needle is almost always an 18 Ga needle. In the same hands, and with the same patient, the spinal is most likely less painful. Both are inserted after local is injected into the skin and subcutaneous tissue so it’s possible that you only feel the local injection.

That will depend on the plan set forth by your anesthesiologist in conjunction with the preference of your surgeon. The definition of "sleep" is different in anesthesia terms. MAC anesthesia (a term coined many many years ago which stands for "Monitored Anesthesia Care") basically means sedation. Typically you are still breathing on your own with supplemental oxygen. Sometimes, local anesthesia can be administered by the surgeon in the field or by the anesthesiologist through a "block" or injection of local around a nerve that innervates the surgical field. Also, a Bier block can flood the field and extremity with local utilizing a tourniquet to keep the medication in the surgical field. Most likely you would not be aware of much, if anything under MAC anesthesia though on occasion you might remember some parts of the procedure. They can also perform the surgery under general anesthesia but this probably isn't the most common method for Carpal Tunnel Surgery. With general anesthesia, airway devices are often placed to assist with your breathing and you are often attached to a ventilator (breathing machine) and given inhalation agents to keep you asleep. When you speak to your anesthesiologist, this should all be described to you.

Always tell your anesthesiologist of any medications (including illicit / illegal drugs). They use this information to provide you the safest anesthetic. Marijuana doesn't alter anesthesia to a great degree. If smoked frequently, lung reactivity can be increased as with any smokers. The decision to proceed will be made by the anesthesiologist in your best interest of safety based on your entire health history. The more information you provide, the better and safer it will be for you as you undergo anesthesia.

The CT scanner is very different from an MRI scanner. CT scans are very fast and are not enclosed. It's basically a donut magnet that is about 1-1.5 feet thick. MRI scanners are more tubes that are much more claustrophobic. There are "Open MRIs which are much better. These look like a large disk about 6 feet in diameter hovering above you while you get scanned.

There are a number of reasons why you are under more risk as a long time smoker. The answer is yes. In order to undergo surgery safely, you should be evaluated by a physician to ensure your health is optimized.

This would be extremely unusual. There are dentists who offer sedation. There are dentists who work with anesthesiologists and/or nurse anesthetists to offer sedation. General anesthesia has been given for dental procedures but these are usually much more extensive than a root canal.

http://depts.washington.edu/awaredb/publication-subcategory/1

Here is a link that will answer your question.
They quote studies that vary from 0.1% to 0.023%. It is very rare.