Insider's Guide to Spinal Anesthesia: What you should know.

Your anesthesiologist may recommend, or give you the option of, spinal anesthesia for your surgery. Here you will learn what they are good for and understand the benefits and risks of spinal anesthesia.

A spinal can be done alone, in conjunction with an epidural (common in labor- more on this later), in combination with sedation "twilight" anesthesia or even combined with a general anesthetic.

This article will focus on a spinal anesthesia that is being used as the main anesthetic for your surgery. The most common surgeries done with spinals are cesarean sections and knee and hip replacement and perhaps other surgeries on the lower extremities.

Definition: Spinal anesthesia uses medication injected into the spinal fluid in the low part of your spinal column. The medication, a local anesthetic, makes the lower half of your body numb, and you will not be able to move your legs. Your consciousness is not affected by spinal anesthesia.

Pre-op: When you talk to your anesthesia provider before your surgery about a spinal , be sure to let him or her know if you take any medications, especially those that "thin the blood". Aspirin and ibuprofen are over-the-counter meds of concern. Just as important, but sometimes overlooked, are herbal supplements. Fish oil, garlic, ginseng, vitamin E and several others cause excess bleeding, especially in combo with certain medications. Usually, by themselves, the herbals won't be a problem, but your anesthesiologist must know if you are using them.

Prescription blood-thinners absolutely must be brought to the attention of your anesthesiologist. Many of these take a week or more to be "out of your system". They may want to avoid spinal anesthesia if you take these medications.

Also, be sure to tell the doc if you have pain or other nerve problems (like tingling/numbness) of your back or legs. If you have had surgery on your back, that information will be useful when deciding if a spinal is right for you, also.

Spinal Anesthesia Technique: You will probably be lightly sedated before your spinal anesthetic, unless you are having a c-section (no sedation for baby). This means you will be relaxed but will still talk to the anesthesiologist when they ask you questions during the placement of the spinal anesthetic. After applying monitors for your heart rate and blood pressure, you will either sit up or lay curled up on your side. Your position is quite important for the success of the spinal anesthesia technique and success in many cases.

Your anesthesiologist cleans the skin with sterilizing soap. A sterile drape covers your back. Then, numbing medicine for the skin is injected with a very small needle. This burns a little at first, but quickly dissipates. The anesthesiologist will tell you they are starting and to hold still. Another special hollow needle is used to find the spinal canal. When the anesthesiologist reaches the cerebrospinal fluid -- the CSF, they inject the numbing medicine slowly. You should not feel any pain, tingling, cramping or "shocks" during this phase. If you feel these things at any point, tell your doctor. They may need to adjust the needle a little to avoid irritating a nerve root. If you feel this, it doesn't mean anything bad is happening, but your doc needs to know.

How it works: The small amount of numbing medicine injected spreads out in the spinal fluid to bathe the nerves that supply the lower half of the body. They become numb and you may lose the ability to tell where your legs are in relation to your body. You will not be able to move your legs. This effect is normal and will usually last, at least, a couple of hours. Depending on how high the spinal spreads, you may also feel a little bit like you can't take a deep breath. This results from numbing of nerves of the abdomen and lower chest wall. Normally, even though you aren't aware of it, when you take a deep breath, your can feel your abdomen and chest rise and fall with each breath. Some people who are sensitive to loss of this sensation feel anxious when they aren't able to tell their chest is moving. Tell your anesthesiologist if you feel this and he or she should be able to reassure you that they are watching your breathing and oxygen level on the monitors and you really are just fine.

During the surgery: If you are having spinal anesthesia without general anesthesia, you will likely also receive sedation during the surgery, again, except for cesarean sections. Many times, people sleep through their surgeries, although they are not unconscious, and don't remember much afterwards. Please note, though, that this is NOT general anesthesia. If you do have memories of people talking to you, or about your surgery, it is normal. This is not "anesthesia awareness", or waking up during your surgery abnormally.

Spinal anesthesia recovery: After surgery is over, you will go to the recovery room. Your spinal will not wear off right away, and in fact, may last a couple more hours. It will wear off from the top down and provides continued pain relief until it's gone.

Why would I choose this instead of going to sleep? What are the benefits of spinal anesthesia vs. general anesthesia? In many cases, it's personal preference. Some people don't like the idea of losing consciousness. Others have severe nausea and vomiting with general anesthesia.

*For surgeries like total knee replacement, there is evidence that patients who have spinals for their surgery have less risk of forming blood clots in their legs and less blood loss during and after the surgery. This benefit must be weighed against any potential problems with the spinal, so talk to your anesthesiologist about what is best for you.

*When the anesthesiologist injects the numbing medicine into the spinal fluid, a pain medication can be injected along with it. This pain medication, usually a narcotic like morphine or dilaudid, helps with pain relief for up to the first 24 hours after surgery, reducing the amount of narcotic you need to have in your IV. Because the spinal narcotic is not circulating in your blood, affecting your whole body, side effects may be reduced, as well. You can still get nauseous and itchy from the narcotic pain medicine, but it's usually not as bad as with the IV meds.

What spinal anesthesia side effects can occur? After the spinal fully wears off, there aren't really many spinal side effects. You may have a sore spot on your back where the spinal was done. If you had narcotic pain meds into the spinal space, you can have some nausea. The most common side effects of "intrathecal narcotics", though, is itching. We don't know exactly why this happens, but people itch with narcotic in the spinal fluid, just as they do if these drugs are given intravenously. The itching is especially prominent on the face around the nose. Other people will have all-over body itching. This is mostly just annoying but can be pretty bad for some people so they have trouble resting or sleeping. Your doctor can order some IV Benedryl or other remedy to alleviate this problem.

Will I get a spinal headache? Spinal headaches used to be more common with both spinal anesthesia and spinal taps to test for meningitis. The theory behind the spinal headache involves leakage of spinal fluid. The lining that holds the spinal fluid around the spinal cord and nerves is called the "dura". When we do a spinal, we must go through the dura to inject the medication. The needles used to be much bigger and therefore, more leakage of spinal fluid occurred, and thus, more headaches.

Now, we use MUCH smaller needles (24, 25 or even 27 gauge for those who know how small that is). Also the needles are actually not sharp, but blunted on the end. An introducer needle -- a short, hollow needle is used to get through the skin and overlying layers. The skinny spinal needle doesn't need to 'cut' through anything. It just passes bluntly through the membrane over the spinal cord, separating the fibers instead of making a hole in them. As a result, little spinal fluid is lost during or after the procedure, and headaches now are very unlikely-- way less than 1%.

Can I become paralyzed from the spinal? Because the needle we use is tiny, and because there is no spinal cord, just nerve roots, at the level where the medicine is injected, there is almost no risk of damage to the spinal cord itself from the spinal needle.

The biggest risk involving spinals and paralysis concerns people who are on blood-thinners like heparin, lovenox, plavix, coumadin or similar drugs prior to the spinal. In these rare cases, one of the epidural veins outside the spinal space bleeds and can't clot because of the medication. The blood forms a mass called an epidural hematoma. Because the blood can't drain, the hematoma gets bigger and bigger. Eventually, the hematoma pushes on the spinal cord causing damage to the cord. This is exceedingly rare but is an emergency when it happens. Surgeons need to drain the blood from the back within a few hours of symptoms starting in order to have hope of recovering function from the damaged cord and nerves. When this has occurred, the patient has usually complained of back pain, and loss of movement of the legs after the spinal had previously worn off.