One of the preoperative decisions prior to hip or knee replacement surgery is what type of anesthesia will be administered. Before your surgery is scheduled, your anesthesiologist will review your past medical history, give you an exam and then discuss the type of anesthesia recommended for you. Ultimately, the final decision is made jointly between you and your anesthesiologist.
General anesthesia involves a complete loss of consciousness, while regional anesthesia numbs a specific area of the body without altering brain or breathing functions. Occasionally, an anesthesiologist will strongly recommend one over the other because a of patient’s current medical condition or because of the type of procedure.
At first, many of my patients say to me, “Just knock me out; I don’t want to remember anything.” That’s when I explain that even if a regional anesthetic is used, they will be given sedatives, will be asleep throughout the procedure and will not remember the surgery.
Prior to choosing which anesthesia is best for you, your doctor should consider several factors including:
- Have you had anesthesia before, what type and what was your reaction/experience?
- Do you smoke, drink or use recreational drugs?
- Are you currently overweight?
- Are you being treated for any condition other than your joint replacement?
- What medications, nutritional supplements, vitamins, or herbal remedies are you taking?
- Do you have any allergies, drug or otherwise?
- Have you ever experienced bad side effects from a drug?
General anesthesia affects the entire body, acting on the brain and nervous system to induce a deep sleep. Usually, it is administered by injection or inhalation of special gasses. Some of the side effects from general anesthesia can include:
- Having a sore throat after surgery, if a tube is placed through the mouth and into trachea to control breathing.
- Historically there has been an increase in nausea after general anesthesia, although with modern drugs and techniques, this occurs much less.
- Some older patients report more confusion after waking up, or family members notice a patient’s confusion, but this also has decreased with modern drugs and techniques.
There are two types of regional anesthesia: an epidural and a spinal block. During a spinal block, a fine needle is used to inject a local anesthetic between the spinal vertebrae and into subarachnoid space (the fluid-filled space that surrounds the brain, spinal cord and nerve roots). Since the injection site is located below the spinal cord, the spinal cord is not in jeopardy of being injured. Medications also are given first, which help the patient to relax before a spinal block is administered. Most patients never even remember having the spinal block placed.
A spinal block produces a rapid numbing effect typically at the level of, and below the injection site. After the block is placed and it is confirmed that the legs are anesthetized, the anesthesiologist administers different medicines by IV and the patient simply sleeps, but still is breathing on his or her own. Again, I reassure my patients that they will not feel anything or remember the surgery.
An epidural block is very similar to a spinal block except the local anesthetic is injected through a small catheter that is inserted into the patient’s lower back and administers a larger quantity of local anesthetics over a longer period of time than with a spinal block. Unlike a spinal block, the epidural catheter is placed slightly closer to the skin and farther from the spinal cord. The greatest advantage of an epidural block is that local anesthesia can be re-injected through the catheter hours or even days after it’s placed. It is a particularly popular form of anesthesia for childbirth.
For many years, when my patients were having both of their hips or knees replaced during the same anesthetic session, they were given epidurals. We no longer do this because better forms of postoperative pain management have been developed. Because we do not plan on re-dosing the anesthetic after the initial dose, there is no increased benefit over a spinal block. Also, the epidural anesthetic typically requires more skill to place and potentially has more complications.
Although both general and regional anesthesia are safe, I encourage my patients to have regional anesthesia when appropriate because I see fewer side effects.
Benefits of regional anesthesia include:
- Patients do not use a breathing tube, so there is no irritation to the throat and airway.
- During a spinal block, medications also can be administered to help manage postoperative pain.
- There tends to be less blood loss during surgery, because regional anesthesia lowers the blood pressure during surgery, potentially reducing the need for a transfusion.
- A number of studies have reported a lower incidence of deep vein thrombosis (DVT), which is the forming of blood clots.
- Patients tend to wake up in the recovery room more smoothly and with less pain.
- Patients also tend to wake up feeling better, especially because there is less nausea.
- Sometimes older patients are more vulnerable to confusion after general anesthesia. In my experience, when using regional anesthesia I see much less confusion in this group. I think this is because fewer drugs are used during surgery.
More now, than ever in my career, I recognize that my patients feel much better almost immediately after surgery and routinely tell me the next morning how clear-minded and well they feel. Hence, they want to go home much more quickly.
Many of my patients who have experienced general anesthesia often tell me how vastly different and better it was to have a spinal block for surgery. Regional anesthesia does make a difference, but the overall experience for my patients is greatly enhanced by the multi-modal pain regimen we follow at The Leone Center for Orthopedic Care, which minimizes use of narcotics.
However, for some patients a regional anesthetic simply is not appropriate, and for those who do have general anesthesia, they also do well with surgery.
And, while most of my patients do choose to have a spinal block rather than general anesthesia, it is important that you consider all of the options and discuss them with your surgeon and anesthesiologist, so the right method with the best outcome can be chosen for you.