Baron Lonner, MD, Chief of Minimally Invasive Scoliosis Surgery at Mount Sinai Hospital, talks about scoliosis and how it affects the system in our bodies and how tethering can revolutionize the way to correct scoliosis.
For our viewers who have heard of scoliosis but may not really be familiar with what’s going on, can you explain what’s happening in the system?
LONNER: So, scoliosis is a lateral or side curvature of the spine. Normally we are straight and, when we look at an individual from the front or from the back, their spine should be straight. A curve to the side one way or another is what scoliosis is but it’s really a three-dimensional curvature that has not only a curve but a twist to it, and it occurs in about two to three percent of the adolescent population and we see it even greater numbers in the adults either untreated scoliosis from their childhood or new onset adult scoliosis.
What are some of the treatments? Would it depend upon the severity of the curve?
LONNER: In the pediatric population in growing children, for example, curves that are mild we just observe. We keep an eye on them so that, with time, if there’s no progression or worsening of the curvature, there’s really no treatment that is required but for larger curves. Those that are getting worse with growth and time, we will tend to brace those patients, so offer them a brace, which is an external—like a corset—that’s made out of plastic, and that helps to control the curve and prevent the curves from getting worse and to require surgery. Then for larger curves, especially in growing children but also those who have reached the end of growth with larger curves, we’ll offer surgical correction.
Within that surgical correction, can you talk to me about the old way of doing it and then tethering, if you could explain what tethering is?
LONNER: The way that it is done most commonly to this day and has been done for the last more than a century, really—-and here we are in New York—the first spinal fusions for scoliosis and spinal curvatures were done at two institutions in New York at the turn of the last century. And so we’ve been doing spinal fusions for over a century, and that’s still the most common form of treatment for most curves. And what is…
Doctor, I’m going to stop you for a second. I’m going to have you just walk it through, talk it to me In terms of we were talking about the fusion surgery.
LONNER: So spinal fusion has been done for a long time. It’s been done for over a century. The techniques, of course, have changed and evolved and it works very well for most patients but what it entails is generally we go from the back of the spine and we open up the spine, we remove the joints where motion occurs between one segment of the spine and we take those joints out to make the spine more flexible and then we place screws at multiple levels of the spine and connect those screws with two rods made out of, usually, cobalt chrome. So, that allows us to get a correction usually very dramatic and a strong, stable correction, and we hold that correction with time. The process of fusion occurs over the ensuing three to six months where the spine basically biologically welds together and forms a column of bone within those segments that are fused.
And then talk to me about tethering. What’s new about that?
LONNER: So tethering is really a revolutionary change in the way we correct scoliosis. What is done is we go through the patient’s side through very small incisions. We use a scope and video monitor to allow us to do this through very small incisions. And we don’t take the spine apart, we really—what we do is place screws into the vertebral bodies, which are the building blocks of the spine, and we connect those screws together one another. We link them up through a flexible cord – it’s like a rope. And that’s the tethering procedure. And we get a correction at the time of surgery and, with growth, there’s gradual correction of the spine because the other side is—the long side of the curve is tethered or held. And then there’s further growth on the concave or the inside of the curvature and, with time, the curve corrects further.
Does the tethering have to be removed or is that a permanent part then of someone’s spine?
LONNER: We have hope to leave the tether in permanently, but in some patients there can be overcorrection. If they have a lot of growth left and if the device is working well, it may work too well in a sense and they can correct and continue to correct. If we see that with remaining growth, then we’ll recommend to the family that we should either remove or cut the cord in the locations where overcorrection is occurring. We have that discussion with all of the families and it’s almost kind of a proof that the procedure works and that we’re straightening the spine, but also preserving flexibility and movement, which is what distinguishes it from a spinal fusion.
What’s the benefit and which patients are best suited for the tethering?
LONNER: The benefit of tethering is we don’t permanently alter the spine and we maintain flexibility and some growth for the patients. If you are an individual involved in dance or gymnastics or high level sports, it’s and really just for almost anybody, it’s nice to be able to have your spine working the way it was intended to work and have movement and mobility to it. The problem with the spinal fusion is, although it works very well for the vast majority of patients as they get into their older years and their adult years beyond childhood, some patients will develop low back or neck pain after a spinal fusion because all the loads and all the motion occur in the remaining segments of the spine that haven’t been fused. I see those patients in their adult years and some of them have problems that require further surgery. The promise of tethering is that it maintains flexibility for the patient. We have a lot of high-level athletes, swimmers, dancers, gymnasts, et cetera, and so they really kind of gravitate to this procedure. We don’t know yet because we don’t have long-term follow-up, but the hope is that there’ll be less problems below and above the tethered segments than what we might see with spinal fusion.
What’s the recovery like? Is it easier on patients who have the tethering or is it about the same?
LONNER: So recovery with the tether procedure is really the first few days are not too dissimilar. That’s difficult for everybody regardless of the procedure but after the first few days the recovery is, I think, dramatically different for the tether patients. They really get back to their activities sooner. We allow them to get into a swimming pool at three or four weeks after surgery and they can walk and do kick board. Then beginning at six weeks, full activities are allowed. Takes a little bit of time to get back to full strength, if you will, but we get our patients into physical therapy and then allow them to pursue their sport or activities. With spinal fusion, we hold the patients back for at least three months, and so it’s more of a recovery. The procedure has more blood loss associated with it, spinal fusion does occasional infections, and we don’t see that really haven’t seen that with tether. In fact, in almost 350 patients, I have not had to give a blood transfusion to one of my tether patients. So the blood loss is quite low.
Will this become the gold standard at some point?
LONNER: I think it will become a gold standard for the right indications for the right patient and I believe it’s going to take hold as we’re seeing excellent results in again, the right patient, the ones who are carefully selected. I think it’ll replace a lot of spinal fusion surgery in the future.
Can you speak to me a little bit about Alivia’s case?
LONNER: Alivia is terrific. She is a full of life and full of passion for dance and is just a lovely young lady. She had the tether procedure done almost two years ago now. She was braced for scoliosis, which is not an uncommon scenario. Unfortunately, her curves progressed or got worse despite the brace. Alivia and her family came to see me after the brace had failed and they knew that spinal fusion was the option that most doctors were offering them and were hoping for something else, and I offered the family and Alivia the tether procedure which, for her case in particular, as a dancer, and the fact that her curve extended into the lumbar spine the lower part of the unribbed portion of the spine where flexibility is, really, the greatest and most important for a dancer. Her curve type was really very amenable to this procedure and would be very beneficial to her in order to maintain her ability to dance and her flexibility and function.
Had she had the fusion option, would dance have been possible for her?
LONNER: I think dance would have been possible for Alivia if she had a spinal fusion but I think it would have been impacted because the fusion would’ve had to extend into the lower portion of her lumbar spine. In my experience, it does impact dance. For some patients, they’re able to make up for the loss of flexibility through the remaining segments of their spine. But there’s a price to pay for that because, over the years, those segments can wear out prematurely as a result. I think this was the best procedure for Alivia to maintain her dance and her function.
Is there anything that I didn’t ask you that you would want people to know?
LONNER: Yeah. The other side of tether, we talked about the possibility of overcorrection with growth, where in which case we would remove or cut the cord in someone who’s still growing and showing signs of overcorrection. The other possibility is that, over the years, the cord can break in one or two locations, and we’ve seen that in up to a quarter of our patients but the vast majority of them hold their corrections and have done well and there’s no consequence to that. But there may be some who lose significant correction over the years and, in those cases, they would have the option to have the cord replaced. Of course, spinal fusion always remains an option, but we try to avoid that wherever we can and I think the future holds for better cords that we’re working with our engineers with the implant company that we’re partnered with to have cords that will be two or three times stronger, and I see that coming in the near future. So, this is a model of a patient or in this case a model with a spinal fusion with the implants that are used for a spinal fusion. The implants consist of screws, we have several screws shown here. We usually put far more screws than are shown here. Then we attach those screws with metal rods that go up and down along the spine, so that part of the spine will not move. The fusion is really the biological welding of the spine where the bone basically forms a sheet here like a bony column, a marble column almost. All the motion in this illustration in this model will occur below the fusion. In this case, there are three discs below the fusion, and those will be the remaining segments that take up all the motion and all of the stresses and loads of daily life.
That’s where the pain could occur.
LONNER: Some patients, especially over the years throughout life, can develop a disc degeneration or wear and tear and back pain, in some cases sciatica, and some patients will have neck pain or upper back pain as well.
So point out the screws to me.
LONNER: Here are the screws, they’re called pedicle screws that we place into the spine, and we use, generally, a lot more than what is shown here. Then here are the metal rods, these are made out of cobalt chrome that we use to connect screws from the top to the bottom and then all the motion occurs below the fusion. In this case, there are three discs below, and those can wear out over time. It’s called disc degeneration, or wear and tear of the discs and that can result in back pain and sciatica. Those patients in some cases even go on to require an extension of the fusion down to the very bottom of the spine.
OK. And then with the tethering.
LONNER: This is a model of the spine if we look at the spine from the back and many families will ask about the bumps on their child’s back up here. We all have it. That’s the spinus process—-that’s the normal bony process of the spine. Basically, in our tether patients, we don’t touch the back. We don’t go through with an incision in the back, we don’t move the muscle aside, we don’t take out the joints of the spine as we do with spinal fusion and the screws go here and the two metal rods. What we do is we go through very small incisions in the patient’s side. We don’t disrupt their anatomy in any way except for placing screws into the vertebra, which are the bony building blocks of the spine separated by the discs the shock absorbers, where motion occurs. Then we place these screws out to the other side and the screws are connected with this flexible cord, the tether. And in some patients who have tethers that extend into the lumbar spine and maybe have a little less growth, so we’re not worried so much about overcorrection, we’ll place a second row of screws and a second cord, as we did for Alivia. So, we place screws through the vertebra or the building blocks of the spine. These are separated by discs, or the shock absorbers, where motion occurs. We place the screws across from one side to the other and then we connect the screws with a flexible cord, again, the tether. That permits motion mobility and also growth. In some patients, we’ll extend a second row of screws into the spine, especially when we’re tethering into the lumbar area where there’s more forces on the tether to make it stronger, especially with someone who has less growth left and we’re not worried about overcorrection as much.
Interview conducted by Ivanhoe Broadcast News.
END OF INTERVIEW
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