epidurals

Where are  epidurals for knee surgery given?  Are they below the spine or actually given right into the spinal column? Is there any risk of paralysis with epidurals?

Thanks.

[Michael L Gross, MD]

Let me try to expand on the answer I gave you previously.  I hope this addresses your concerns more completely
Several factors must be considered when selecting anesthesia, including:

1. Your past experiences and preferences. Have you ever had anesthesia before? What kind? Did you have a reaction to the anesthesia? What happened? How do other members of your family react to anesthesia?
2. Your current health and physical condition. Do you smoke? Are you overweight? Do you drink or use recreational drugs? Are you being treated for any condition other than your joint replacement?
3. Your reactions to medications. Do you have any allergies? Have you ever experienced bad side effects from a drug? Which drug? What were the side effects? What medications, nutritional supplements, vitamins, or herbal remedies are you currently taking?
4. The risks involved. Risks vary, depending on your health and selection of anesthesia, but may include breathing difficulties, blood loss, and allergic reactions. Your surgeon and anesthesiologist will discuss specific risks with you.
5. The skill and preferences of your surgical team

Regional anesthesia involves numbing a specific area of the body, without affecting your brain or breathing. Because you remain conscious, you will be given sedatives to relax you and put you in a light sleep.  For knee surgery , a combination block that targets the lumbar plexus and the sciatic nerve can numb only one leg. The differnce between epidural and spinal anesthesia is not the level, both can be given at the same level, but in the depth of penetration, and the method of delivery for the anesthetic.

In a spinal block, the anesthesia is injected into the fluid surrounding the spinal cord in the lower part of your back. This produces a rapid numbing effect that can last for hours, depending on the drug used.

An epidural block uses a small tube (catheter) inserted in your lower back to deliver large quantities of local anesthetics over a longer time period. The epidural block and the spinal block are administered in a very similar location; however, the epidural catheter is placed slightly closer to the skin and farther from the spinal cord.

Side effects from regional anesthesia include headaches, trouble urinating, and allergic reactions, which could be quite serious. Permanent, complete paralysis is a rare, if not unheard of, complication.

In knee replacement surgery specifically, there are several advantages to using a regional anesthesia rather than general anesthesia. Studies have shown that there is less blood loss during the surgery, and fewer complications from blood clotting afterwards.  

If an epidural block was used during your surgery, the epidural catheter can be left in place and anesthesia continued afterwards to help control pain. You will also have control over the amount of pain medication you receive, within preset limits. This allows for effective pain releif, while maintaining a clear head.