Interview with Dr. Mohammed Diab: New Treatment for Scoliosis

Audio Interview

Scoliosis is an abnormal curvature of the spine that's typically treated with bracing or an operation called spinal fusion. Now, a new procedure, called spinal tethering , is a more effective alternative than bracing and one that allows for growth and more normal function in children.

Hear an interview with Dr. Mohammed Diab, a pediatric orthopedic surgeon at UCSF Benioff Children’s Hospital who helped develop this new procedure and who is the only surgeon performing vertebral body stapling in the western U.S.

Interview Transcript

Andrew Schorr

Imagine your child has severe curvature of the spine, scoliosis, and you're told that he or she might need to wear a brace for several years. Is there be a better approach? The answer is yes. We'll hear about it next on Patient Power.

Andrew Schorr

Any of us with children want the best for our child, and if there's a health concern you want to get the best care. Imagine you have a young child whose spine is curved a lot, and that is scoliosis. We're going to learn about that, and the procedures that have been changing over the years. We've been looking for a better way and, at UCSF, they've been pioneering vertebral stapling. A man who has really pioneered that is an orthopedic surgeon and chief of pediatric orthopedics at the UCSF Benioff Children's Hospital, Dr. Mohammed Diab.

Dr. Diab, thank you so much for joining us. Let's just start with the basics. How do you define scoliosis?

Defining Scoliosis

Dr. Mohammad Diab

Scoliosis is an abnormal curvature of the spine. If you look at someone from the side everyone has normal curvature of the spine. In the chest area, your spine curves backwards. In the flank area, also known as the lumbar area, your spine curves forward. In your neck, your spine curves forward. So that's normal. But if you look at someone face to face, the spine should be straight.

In scoliosis if you look at someone face to face, the spine is curved to the side. In addition, it twists, so we think of it as a 3-dimensional abnormal curvature. It goes side to side, and it twists.

Andrew Schorr

If you talk about degree, how many degrees might somebody be curved?

Dr. Mohammad Diab

The curve is measured in degrees. One assumes that in the normal state, when you look at someone face to face if their spine is straight, then it's zero degrees. One could think, well, actually that's really 180 degrees, but we call that zero. Any deviation from that is given a number, and it's measured. It's usually measured on X-ray. We say that you have to have 10 degrees to be even called scoliosis.

So if you're under 10 degrees, we consider you to be a normal variant. We often see patients with curves under 10 degrees referred to us, and a wise surgeon from Toronto once called that schooliosis, not scoliosis, because often it comes from a school screening program by the school nurse.

But once you're at 10 degrees, we call you scoliosis. Then we have all ranges of curves. It can be 20 degrees, it can be 30, it can be 50, it can be 80, it can be 100. There are a wide variety of ways that patients will present.

Andrew Schorr

Now, I mentioned earlier about braces. What have been the traditional approaches? Let's talk about younger kids. So you have a four-year-old, a five-year-old, and they have this terrible curvature, maybe pain, discomfort, things they can't do, and you worry as a parent about their future. What have been approaches traditionally in your field?

Dr. Mohammad Diab

We divide patients with scoliosis in different ways. One way is according to age. If you have scoliosis above 10 years of age, we call you an adolescent scoliosis. If you have scoliosis in the first maybe three years of life, we would call you an infantile type scoliosis. Between 3 and approximately 10, we refer to that as juvenile scoliosis.

The patients who have adolescent scoliosis, if they need a brace, they need it for maybe a few years. The patients with the infantile form, the zero to 3 years of age, that scoliosis can behave unusually, including go away, so those patients often don't need any treatment.

The patients between 3 and 10 are the most challenging because they have a long period of growth ahead of them and because the type of scoliosis that sets in at that age period is particularly progressive. It has a tendency to get worse much more often than the other types. So those are the patients that are of most interest for coming up with a different approach to treatment. They have a long period of growth ahead of them, and their curve tends to progress more than the other types.

The traditional approach and the current approach to scoliosis consists of watching curves until they get to about 25 to 30 degrees in magnitude. Once they approach that number, we consider non-operative interventions and in particular bracing. Once the curve exceeds approximately 45 to 50 degrees, then we consider surgical treatment.

So if you take a step back and ask yourself, well, what are the treatments for scoliosis, divide them into non-operative and operative. The non-operative approach is bracing, and we recommend it for curves approximately 25 to 30 degrees. The operative approaches can be divided broadly into two categories. The traditional approach is fusion surgery, where we stick the bones together so they can't bend anymore, and we use different techniques including implants to accomplish that.

The Most Innovative Treatment

The other approach — which is the current, newer, innovative . . . where so much of the buzz is — is the so-called fusionless surgeries. In that category, there are maybe two different types but only one that's realistic or viable to patients today, and that is the vertebral stapling. Vertebral stapling is used not at the same curve magnitude as traditional spine fusion, i.e., 45 or 50. Instead, it's introduced to a patient earlier in the bracing range as an alternative to bracing. It acts like an internal brace, as opposed to a brace, which is on the outside.

Andrew Schorr

Well, I can't even imagine my child wearing a brace for many years, so when you talk about an alternative I want to hear about it. Now, I understand staples for the body or along the spine have been around for years. They were tried maybe back in the 50s even. But you have helped pioneer it being used now where it didn't prove to be effective then. What's changed? Tell us about that.

Dr. Mohammad Diab

There's a man, a surgeon called Blount from Milwaukee who introduced stapling in the 40s to modulate the growth of the long bones.

So bones are divided into categories. The bones of, let's say, your lower limb or your upper limb are called long bones because when you look at them, they're long. There are other types of bones. For example, the bones of the spine, each one is called a vertebra, and those are irregular bones. So the staple was introduced not for the spine. It was introduced for the long bones specifically of the lower limbs, and even more specifically around the knee because kids can get very bad knock knees or bow legs.

Kids have things called growth plates. They are different from adults. We don't have growth plates anymore once you're an adult. The growth plates are the centers from which your bones grow.

In the long bones, you usually have a growth plate at each end, not always, but most of the time. The fastest growing growth plates in your body are around your knee. If you have knock knees you can put a staple, which is a metal bracket, on the inside of your knee, either in the thigh bone or the shin bone. Those are the two bones that make up the knee and control the growth plates on the inside while the outside part of the growth plates keep on growing. You can swing from a knock knee to a straight position with time. That was the concept of growth modulation.

After that became established and was shown to be effective, and it still is today a tried and true method because it works well, a group of surgeons, one in particular who did a lot of this from the UK started stapling scoliosis, the thinking being if a spine curves in one direction that means that on the convexity the bones are growing a little bit faster than on it concavity. The thinking was, just like with knock knees and bow legs, if one came in and inserted staples on the convex side of the spine where it's growing a little bit faster, that growth can be slowed down while the concave part of the spine was allowed to continue to grow and thereby catch up and hopefully straighten the spine.

The problem is that the staples in the original form back in the 40s and 50s were not strong enough to hold in the spine because it's a different setting. In the long bones, you can put in the staples and they can stay within the same bone.

In the spine when you put in the staples, you put in the staples across, between bones, so there's motion between the two bones, and so the staple feels that motion. With time, that means multiple, repetitive movements in a day and then in a week and then in a month in a given child. Those staples can wiggle out.

Staples wiggle out even from long bones where there's not that much motion. They certainly can wiggle out of the spine. So the early experience with staples in the long bones was good, but in the spine where they were crossing between bones, was not good and there were many, many failures. A, they didn't hold, and B, they'd back out of the spine and would float around in the chest.

Andrew Schorr

So my understanding is the innovation was in developing a technology where I think you keep the staples cold in the operating room and then when they are inserted in the body and they warm up they curve and sort of lodge themselves?

Dr. Mohammad Diab

The traditional staple is a piece of metal with two prongs that are at 90 degrees to the main stem of the device. If you impact them into a bone, they stay there by interference, but they theoretically could back straight out the way they were inserted.

The innovation in the spine has been the use of a memory metal. It's called nitinol. It is an acronym, and it refers to where the technology was developed, in the U.S. Navy, and to the alloy, nickel and titanium, that the staples are made of.

Being a memory metal, when frozen . . . these staples are kept on ice, they can be shaped to a given shape and they'll stay that way. But once they are heated up to body temperature, they will assume their original fabrication shape. So they are made with a stem and two or four curved prongs. When they are frozen those prongs can be straightened out with a device and they can stay that way. But once they are inserted, the body temperature will make them assume their original shape, which is to have tines that are curved.

The fact that the tines can be put in straight because they're cold and then curve within the bone means that the channel changes. The channel of insertion now is different than the channel of backing out. And for them to back out because now the tines or the prongs are curved, they would have to cut through bone, and that's much more difficult. So the early experience has been that these staples stay in and do not back out the way the original staples would.

Andrew Schorr

Now, Dr. Diab, I understand that you in your work that you're doing at UCSF, you've really been a leader nationally and certainly west of the Mississippi in the United States in doing this six-hour procedure. But it's really changed things for some children that have benefitted from it. I know I read of some children where it's just been incredible for them.

Dr. Mohammad Diab

We have begun stapling certain kids. I was slow to move because the original person who began this new experience had not done it experimentally. He understood the theory, he's an excellent surgeon, and he applied it directly to patients. There was precedent because this is old technology and has been done before. For me, we were slow to move because medicine has been taken down many a garden path only to find out that given treatment does not work or is not effective for patients. So we waited until we did a cadaveric or a lab-based experiment.

Several years ago, we did that using a calf spine model and showed that indeed the staples work in the lab the way that the theory would suggest. Once we did that, then I felt comfortable introducing it to patients.

The other thing we've done here is we've been very careful in our indications. One of the temptations of new technology is to take it and run with it and run in every direction, and physicians historically have been a little guilty of being too excited with a new treatment and applying it broadly. We've been careful here to apply to a very select group of patients.

Who Can Benefit From Stapling?

The specific group is the one group of patients that it has become clear do not benefit from bracing, the one group of patients where bracing probably will be ineffective. A group out of France has shown that patients who are under 10 years of age with a scoliosis 30 degrees or greater will end in a spine fusion regardless of treatment, including regardless of bracing. So for me, that's the group that most needs an alternative treatment, alternative to bracing and alternative to fusion, and so fusionless surgery. For that group, we have introduced stapling with so far success.

But I say this with caution because the experience in the world is still early. Our early experience has shown that every patient who has undergone stapling at our center for this indication, again, under 10 years of age, greater than 30 degrees, has shown a stabilized curve. Not magical correction, but just a curve that does not get worse. And if I can keep kids at 30 degrees throughout their childhood, then they'll never need anything more from me. So our early experience has been encouraging, but we're not ready to celebrate yet because this is still very early in the overall, worldwide, collective experience.

Andrew Schorr

Well said. Now, just to put this in perspective, as I alluded to earlier. Six-hour procedure, you're putting in the staples. They will always remain in. The child will grow, and would they need other surgery down the road?

Dr. Mohammad Diab

The procedure length really varies, but roughly four to six hours. Many people do the operation with the aid of a telescope. I used to do it that way, but now, I do it open. I find that the incisions that are necessary to be made to perform the operation with a telescope, if you add up the length of each one of these incisions, they end up being as long as a single incision in my hands. I also do the incision in a certain way that makes it heal quite cosmetically and makes it covered by the arm when the arm is at the side of the body.

We insert the staples without sacrificing any of the tissues. For example, there are blood vessels that cross the bodies of each vertebra, and I insert the staples without sacrificing those blood vessels whenever I can. There are occasional patients who are so small that it's practically difficult to insert the staples without doing that. For the most part, we can.

The theory is that we'd like to put in the staples and hold the curve where it is. It's the same goal of an external brace for, let's say, the adolescent. If the patient comes at 30 degrees and you the surgeon brace the patient, your goal is to maintain the curve at 30 degrees. Your goal is not to correct it to zero. A brace cannot accomplish that. In introducing something different, fusionless surgery, the goal should at least meet that standard.

So, for me, I'm inserting staples so that I can control the curve at that degree. If I can keep a curve at 30 or 35 degrees throughout childhood, and presumably for the rest of the patient's life, then they'll have a normal functioning spine and never have any problems, not with their spine and not with the organs around the spine. So in that case, if I insert staples, then they never need to be taken out, and it's a one-time experience.

On the other hand, theoretically, the staples could control the growth so much on the convex side of the spine and perhaps for long enough that the concave part of the spine can keep growing and automatically correct the curve. If that happens, then once the curve is corrected to zero then the patient would require a second operation to remove the staples. This is what we do in the long bones. If a patient comes with knock knees and we insert staples, once the knock knees have corrected to neutral or we overshoot a little bit into a little bit of bow legs, then we take the staples out. So theoretically, the child may need another operation to have the staples removed.

The third possibility is that the staples don't work. You put it in a child with the correct indications but for whatever reason that we do not understand, the scoliosis that the given child has is so aggressive that it overpowers the staples. In that case you may have to remove the staples as well.

Andrew Schorr

I imagine time will tell as you gain more experience. But this seems to be one of these cases, Doctor, you're a specialist in this and a pioneer in it and yet have a very conservative approach, which I applaud. If a family is dealing with this with that younger patient, 30 degrees or more, a second opinion or coming to see you would be wise, I would think.

Dr. Mohammad Diab

I leave that up to the patients. I'll tell you the reverse of that. My patients who come to see me and we're discussing an operation will occasionally ask if they should get a second opinion, and it's always an awkward thing. I deal with that head on, and I'm quick to help them with that, which is I tell every patient get as many opinions as you need. My patients, I encourage them to go see other surgeons because at the end of the day, ne has to feel comfortable with one's surgeon. There's too much at stake otherwise. So I often encourage my patients to get other opinions. I patients would like to come and see me for another opinion,they're welcome.

Andrew Schorr

Given the worry that parents have about their children, and certainly if you see this pretty significant curvature of the spine, you want to connect with the wisdom that's available in the field. Icertainly appreciate you, Dr. Mohammed Diab, chief of pediatric orthopedics at the UCSF Benioff Children's Hospital for being with us and explaining where we are now and where vertebral stapling can come in for some of these children. Thank you so much for being with us today.

Dr. Mohammad Diab

You're welcome. Thanks for having me.

Recorded in November 2011.


Reviewed by health care specialists at UCSF Benioff Children's Hospital.

This information is for educational purposes only and is not intended to replace the advice of your doctor or health care provider. We encourage you to discuss with your doctor any questions or concerns you may have.

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