What happens during a standard spinal fusion surgery?
Dr. Zahrawi: In the standard procedure you make an incision. The most common one is the posterior fusion where you make an incision in the back, in the middle usually, and then you have to retract the muscle to both sides. Then you have to remove bone to decompress the spine, because most fusions are associated with decompression. But if you don’t need to do decompression you don’t need to remove too much bone. If we are just doing strict fusion, after we expose the bone we do what we call decortication — meaning to roughen the bone. What then happens is it bleeds. When it bleeds it brings the cells necessary to perform the fusion. The cells come from the bloodstream of course. That’s in addition to the bone graft that we put on the bone that’s been decorticated (or irritated if you will), and the fusion happens. If you are doing a decompression, you have to remove some bone in addition to that in the posterior element.
How big of a procedure is standard spinal fusion for patients?
Dr. Zahrawi: It’s not only bigger in terms of time; there is more violation to normal tissue in order to get to the area that we like to put the bone. That area is way outside on the lateral part of your spinal column. So it violates normal tissue, and it’s a longer procedure.
What’s the recovery typically like?
Dr. Zahrawi: Usually, recovery takes at least a minimum of three months for fusion. If people don’t heal immediately, the next step takes about six months. So the least that you require is three months; it could go six months, it could go up to year and occasionally even two years — so it’s a long process.
Generally speaking, who would be a candidate for fusion?
Dr. Zahrawi: Fusion you can do for a variety of conditions. The most common one is deformity, like if somebody has scoliosis or another deformity. Then we do it for degenerative process, like if somebody has what we call a spondylolisthesis or somebody who has a significant stenosis where a wide decompression is required –then we have add the fusion to the decompression. We also do it for tumors, we do it for infections, and we do it for, what we call, degenerative disk disease.
Is degenerative disk disease common?
Dr. Zahrawi: Degenerative disk disease is very common. The fusion we do for degenerative disk disease is slightly different from the fusion we do for scoliosis and deformity. Fusion for degenerative disk disease has to involve the disk itself. If you are treating a patient with degenerative disk disease then the disk itself has to be removed in order to eliminate the pain. If you do only bilateral lateral fusion or, what we call, the far-out fusion alone, the patient is not as good as if you do the fusion between the body itself. When you remove that degenerative disk and replace it, sometimes it’s a bone graft sometime it is hormone. So you need to remove the bad disk and replace it with the element that can do the fusion.
Tell me about this new way you are performing spinal fusion.
Dr. Zahrawi: We have talked all along about posterior fusion. Again this is the most common one. Anterior fusion is a fusion that is done in front of the spine. It’s not a new procedure; it’s been done for a long time — done in a different way. Anterior fusion can be done in two ways. It can be done either strict anteriorly or it can be done laterally. Now anteriorly means you’re facing the vertebrae from the front. So you are facing the vertebrae face on — that is anterior fusion. So what you do after you do the exposure is you go to the disk again. You have to remove that disk and you have to put a bond there. That’s anterior fusion. There is another aspect of anterior fusion — we call it a lateral fusion. Lateral fusion is where you go perpendicular to the spine. Again you land on the disk and you have to remove it — you do the same procedure. You’ve got to remove the disk and you have to replace it with either a cage, bond, bone graft, hormone or combination of the above.
So you go in the side basically?
Dr. Zahrawi: Yes, 90 degrees to the spine exactly. So you have posterior fusion, you have anterior fusion, and you have lateral fusion. Lateral fusion is nothing new. We always went from the side to the back, but we always pulled what we call the psoas muscle, which lies right on the side of the vertebrae. What we’ve done in the past is gone laterally and pulled that muscle backward. That allows us to expose the disk and the vertebrae and do fusion that way. The new technology is that we are going through that muscle, the psoas, so that avoids pulling the muscles again. So if you can imagine where the psoas muscle usually lies is right on the side of the bone. So what we’ve done in the past, we’ve pulled the muscle sideways to get access to the disk. Now, we are going right in between these muscles. With that new technology we put dilators into these disks and do the procedure in a minimally invasive way.
So you have smaller instruments to go in there?
Dr. Zahrawi: What we do is, we make about an inch incision, we put a guide wire, and we position an X-ray right over the disk. Then over that guide wire we put dilators. The smallest ones, the first one is the size of a straw. So that straw dilator goes right over the guide wire. Then we move from that dilator to bigger dilators. These dilators go to about three-quarters of an inch in diameter. This last dilator is retractable. So if you were to retract it, it would give you about an inch-and-a-half opening. Sometimes it will be a two-inch opening all the way around, dilated. So actually we do not cut any muscles; we dilate these muscles. The X-ray and these new instruments guide us and position us right over the disk. So that’s how it’s minimally invasive. We are not violating any muscle. It’s a very tiny, small incision. We are avoiding muscle stripping and muscle cutting because otherwise you have to repair it and heal if.
What does that mean for patient’s recovery?
Dr. Zahrawi: It means a much faster recovery and avoiding a tremendous complication. Sometimes [with the old way] you get hernias through these incisions and the healing time is much longer. You have to allow these muscles to heal. You literally cannot do much for about six weeks until these muscles heal. With this surgery, even though you are going to avoid strenuous activity, the pain is much less because there is not much healing to be done. The muscle has not been cut, so there is no healing from that. You are only going to heal the bone itself, no muscle healing needed.
I know you have also another part of this procedure where you use the nerve guidance system. Can you tell me a little bit about that?
Dr. Zahrawi: The nerve-guidance system is because the psoas muscle is lying right over the side. Inside this muscle there is a lumbar nerves that leaves the spine and comes down through these muscles down to the legs. The dilators that we put over the guide wires have a sensor in them, so to speak. That sensor attached to the machine will measure the activity in these nerves and how fast they are responding to the stimulus. The closer you are to the nerve, the faster the response is. So that would tell us how close we are to that nerve. If we found the response is very fast and short, then we have to reposition and stay away from the nerve. What that does is provide us some safety, so we can operate between these nerves without violating them and damaging them. So that is an important part of the procedure that we call nerve vision.
So not only is it easier on the patient, but it’s safer too?
Dr. Zahrawi: Yes. Correct. It’s very safe. It’s safer since we are not going through the nerve the nerves, and we do not retract them like we do when go from the back – - it’s much safer.
Is this procedure being performed widely now, or about how many doctors in the country are performing this?
Dr. Zahrawi: Well again, the anterior approach is nothing new. The anterior approach has been done and continues to be used. What this does is it replaces the old procedure. Since we have this approach as a new minimally invasive procedure, it’s inviting a correcta lot more spinal problem that way. We can do a lot of the procedures that were done posteriorly by converting them to the anterior approach. So it’s not only the old anterior approach that you can do this way, we are shifting some of the posterior surgery to the front. We’re doing this for a couple reasons: First of all, it can correct deformity nicely, which is harder to do posteriorly. Number two, the recovery time is much faster. It’s becoming much more popular and I think time will show that it’s going to be even more popular.
How exciting is this for you as a surgeon to have this now to offer patients — this as opposed to what was available?
Dr. Zahrawi: I think it’s very, very encouraging. One more thing, as spine surgeons we always used to have a general surgeon in the room with us to do this procedure. Now we eliminate that. We don’t need the general surgeon because we are not exposing any vessels. So anytime we manipulate large vessels we always like to have a general surgeon or vascular surgeon in the room. With this procedure we are not anywhere close to these vessels, so it’s safer from that aspect too, and also we are eliminating the need for a vascular surgeon in the room.
So it’s easier for you too.
Dr. Zahrawi: Much easier, yes.
Is there any way to say how long the recovery time would be compared to standard fusion?
Dr. Zahrawi: There are two parts to the recovery. If we are talking about a fusion you are going to need the three months regardless. But in older people it takes a week to get out of bed comfortably and walk around. With the new procedure, the first day you can get up and walk around. The first recovery from the surgery itself is much shorter. The fusion itself, I have to say it’s probably going to take the same amount of time. It’s going to take about three months for a fusion regardless, whether they do it from the front or the back. What I would say the incidence — as you know there is no procedure perfect — of posterior fusion not healing when we do one level is about 10 percent. If you have two levels, it’s about 20 percent. Three levels — it increases as you include more levels. The data is showing that, the incidence for fusions not to heal is much lower when we do Lateral fusion than when we do the posterior one. So the success rate is higher with this procedure than the posterior one.
What’s the success rate?
Dr. Zahrawi: The success rate for the fusion is better when you do this lateral-anterior approach than to do posterior.
What Kinds of patients can have this surgery?
Dr. Zahrawi: There is two answers to that. The first one is if somebody has nerve damage or pressure over a nerve that has to be relieved. There is no question about that. If somebody has nerve damage it has to be relieved. The pressure has to be removed from the nerve. Now that’s one aspect. Another aspect of that is pain — if somebody is dealing with pain. Of course not every pain or back pain needs to be treated surgically. I encourage every patient to live with that condition, not to have anything done about it as long as they are active and it doesn’t require taking narcotics for a long time. Let’s assume somebody has back pain. If they take a couple Tylenol or aspirin, two or three times a day and function well and are able to exercise, I don’t think they should ever have surgery. Even if it means you take the pain medication every day — as long as you are not taking narcotics. Now, if somebody is taking narcotics for a very long time it’s a different story. I don’t think anybody should be on a narcotic more than three or four weeks, maximum, because as you know, after that you can become hooked on the medication. Then it’s very hard to take you off even if you have surgery. It’s very hard to stop this medication even if you have surgery later on for it. If it takes narcotics to relieve your pain, and it takes more than four to six weeks of narcotics, you should consider seriously having surgery. Think seriously about it; see your spine surgeon that you mostncomfortable with. See if the problem can be addressed surgically. If it requires no narcotic, that’s fine. Number two, if the pain is so bad that patient cannot do any exercise then that is also an area that needs to be addressed and evaluated for surgery. But if somebody can do the level of activity that he or she desires, they are good with that. If somebody just takes some anti-inflammatory or minor pain medication, even if you take the anti-inflammatory for six months or a year, it’s not a problem most of the time. There is no need for these people to have any surgery.
How successful is spinal fusion at relieving the pain?
Dr. Zahrawi: Again, not every patient with back pain is a candidate. There are a lot of cases that sometimes we can’t do anything about. But I’m talking about the lucky ones who find that something can be done about it. I would say about probably 30 or 40 percent of the people can benefit from surgical procedure. If the problem is that arthritis has spread out, there is really not much you can do about that. The more localized the problem, the better the result. If somebody has problems at one level, two levels — okay — those are the most successful. You go to three and four levels then your chance to succeed significantly decreases.