About the Technology
By Dr. Thomas A. Zdeblick
Madison, WI
Degenerative disc disease (DDD) is a leading cause of lower back pain in young adults. Because degeneration is commonly associated with aging, "degenerative disc disease" is somewhat of a misnomer. With age, we all exhibit some degree of degeneration in our vertebral discs. And to add to the confusion, degenerative disc disease is actually not a disease at all, but rather a degenerative condition that can cause pain from a damaged disc. For these reasons, the medical community has been reluctant to agree on what "degenerative disc disease" actually describes.
Despite this confusion, a few aspects of the condition are known. At birth, a vertebral disc is comprised of about 80 percent water, which gives it a sponge-like quality, and allows it to function as a sort of shock absorber between the vertebrae. As the disc ages, the water content decreases and the disc becomes less capable of absorbing the shock. With age, inflammatory proteins within the nucleus pulposus (soft inner core of the disc) also change composition, and tears develop in the annulus fibrosus (the outer hard core of the disc). We can all expect to have some level of disc degeneration during the course of our life, yet we will not all experience back pain. It's not exactly clear why some degenerated discs are painful and some are not.
With the advent of magnetic resonance imaging (MRI), the medical community has started to gain a better understanding of this condition and to develop less invasive and less painful techniques for treating it. As Dr. Thomas A. Zdeblick puts it, "The last thing you need to do when you're treating back pain is create some other pain."
Dr. Zdeblick is the Director of Orthopedic Surgery at the University of Wisconsin (UW). For thirteen years, he has run the UW Spine Center. Dr. Zdeblick holds a Doctor of Medicine degree from Tufts University, and a BS from Marquette University. Prior to accepting a position at the University of Wisconsin, Dr. Zdeblick completed a spine surgery fellowship at Johns Hopkins Hospital and the orthopaedics residency program at Case Western Reserve University Affiliated Hospitals.
The U.S. Food and Drug Administration (FDA) approved INFUSEŽ Bone Graft, in combination with the LT-CAGEŽ Lumbar Tapered Fusion Device, for the treatment of degenerative disc disease. As the following interview with Dr. Zdeblick suggests, this technology could significantly change the way surgeons perform a spinal fusion to treat this condition.
Back.com: Many Americans seem to suffer from lower back pain. Why is it such a significant health problem?
Dr. Zdeblick: Twenty-five to thirty million Americans suffer from chronic low back pain, so it's very common. It's actually the number one cause of lost days from work in the U.S. There are many reasons why we get low back pain. One is that we're just designed improperly to stand on two legs all day. But many of us can be overweight, or out of shape, we don't exercise as much as we should. Smoking has been shown to cause more back pain. So there are a number of reasons why back pain is so common.
Back.com: What exactly is degenerative disc disease (DDD), and how does it relate to lower back pain?
Dr. Zdeblick: All of our discs as we get older do some amount of degeneration. In general, discs, which are the cushion between our vertebrae, can start to shrink with time. They have a little less water in them; they wear out a little bit. But typically that doesn't occur until you're in your 60s or 70s. When you have a disc that starts to do that at a young age, we call that degenerative disc disease. There are a number of reasons why a disc may wear out when you're young: accidents, injuring the disc in a fall, or from an athletic injury. Sometimes the discs, because of genetic reasons, wear out at a young age. As they begin to wear out, you lose cushion in the disc, and then the bones of the spine get closer together. Sometimes the bones actually begin to rub together and that's a painful degenerative disc.
Back.com: What kind of health issues does degenerative disc disease pose for the patient?
Dr. Zdeblick: Degenerative disc disease in a young patient causes a chronic aching low back pain. And it's not the type of back pain that you or I may get that lasts for a day or two, but it's a type of back pain that's daily. They wake up with back pain, it gets worse as the day goes on, and it often begins to impair their ability to work or to enjoy their weekends. Medication helps but they always have that backache. Sometimes it begins to go down into the legs because of narrowing of the disc. When the disc gets very degenerative, when bones are rubbing together, it's not the kind of back pain that you can ignore.
Back.com: What are the treatment options currently available to patients with degenerative disc disease?
Dr. Zdeblick: Most patients can treat disc degeneration without surgery. We usually begin with a physical therapy programactive, aggressive exercise to strengthen the muscles of the trunk, sit-ups and crunches. We often add medication, the anti-inflammatory medications. Chiropractic care can help. Occasionally a brace or a weight lifting belt may be helpful. And really before considering surgery, all of those things should be exhausted.
Back.com: As a physician, how do you decide whether to use a less invasive or more invasive treatment for a patient with degenerative disc disease?
Dr. Zdeblick: Well, we always begin with the less invasive techniques. Certainly, if we can avoid surgery, we'd prefer to do that. So if a patient responds to physical therapy or activity modification or medication, we would leave it at that. It's those patients that have exhausted all of those and really haven't responded that we then begin a consideration of surgery.
Back.com: How effective is traditional spinal fusion surgery?
Dr. Zdeblick: Well, traditional spinal fusion surgery was performed through the back. We would make an incision in a patient's back. We'd have to move their back muscles out of the way. And then take bone graft from their hip, and then place that bone graft down the spine in hopes that by healing the back of the spine, the disc pain would go away. Unfortunately, it wasn't that effective. Only about 50 to 60 percent of patients improved with the traditional posterior spinal fusion, and that was for several reasons. The fusions did not always heal. It was painful to take bone graft from the hip, and we moved their back muscles out of the way which often caused scarring and stiffness in those back muscles, the very things we were treating in the first place.
Back.com: What's different about INFUSEŽ Bone Graft/LT-CAGEŽ Device?
Dr. Zdeblick: Well, the standard spinal fusion surgery requires the harvesting of bone graft. That means an incision has to be made somewhere over the hipbone to take out pieces of that bone to use to get the spine to heal. With INFUSEŽ Bone Graft/LT-CAGEŽ Device, you don't need to do that. You only use the sponge with the bone protein dripped on to it, and you place the sponge within the fusion cage, and that is what makes bone graft. It really eliminates the need to take any bone from the patient's hipbone.
Back.com: So eliminating the need for the second operationthe bone graft harvestingis the advantage?
Dr. Zdeblick: The advantage to this new technique is twofold. With the LT-CAGEŽ Device, you can hold the spine in the exact position that you want it in [Click here to learn more about this procedure, Anterior Lumbar Interbody Fusion (ALIF)]. And with the INFUSEŽ Bone Graft, you don't have to take any bone graft from the hip.
Back.com: What exactly is INFUSEŽ Bone Graft?
Dr. Zdeblick: Well, INFUSEŽ Bone Graft is a combination product. There's a collagen sponge, and then there's the bone protein that's dripped onto it. Now this protein, BMP, is the same protein that we all have in our bodies. It's what makes bone when we break a bone. This bone protein has been distilled and purified, and now a biotechnology laboratory can manufactured it as a pure protein. So this protein, once it's placed on the sponge, stimulates your own body to make bone where that sponge is.
Back.com: How will the use of INFUSEŽ Bone Graft/LT-CAGEŽ Device enhance traditional spinal fusion surgery?
Dr. Zdeblick: Again, INFUSEŽ Bone Graft eliminates the need to harvest bone graft because, in and of itself, it will make bone. Traditionally, we had to take bone from someplace else in your body to place it near the spine. The INFUSEŽ Bone Graft generates bone in that location by itself, eliminating the need for that second incision.
From a surgeon's perspective, INFUSEŽ Bone Graft/LT-CAGEŽ Device is easy to use. It eliminates the 20 to 30 minutes that it takes to harvest bone graft. It's also easy to place the sponge within the LT-CAGEŽ Device and control where you place it.
From a patient's perspective, the advantages are huge. They don't have a second incision and pain from that, and they don't have long lasting discomfort from the site where the bone was removed.
Back.com: Are there patients who are not good candidates for INFUSEŽ Bone Graft/LT-CAGEŽ Device?
Dr. Zdeblick: Not every patient is a perfect candidate for spinal fusion. Multiple level fusions are not effective for treating back pain. The older patient that has weaker bones, osteoporosis, they're not a good candidate for the use of cages and spinal fusion. Certainly, if a patient's pregnant, if they have an active infection, or if they have cancer, they should not be treated with INFUSEŽ Bone Graft/LT-CAGEŽ Device.
In clinical trials, the combination of the LT-CAGEŽ device and INFUSEŽ Bone Graft had a very high success rate. In my personal series, over 90 percent of the patients were happy that they had the surgery performed. [Click here to learn more about this procedure, Anterior Lumbar Interbody Fusion (ALIF)]. And that compares to the 60 or 70 percent of patients that I treated using traditional spinal fusion techniques. We looked at the safety concerns with INFUSEŽ Bone Graft/LT-CAGEŽ Device very carefully. We didn't find any adverse reactions. It's a naturally occurring protein, so it's well accepted by patients. This product represents a huge advance. It's not only effective but safe and eliminates the need for bone graft harvest.
Back.com: Were there other differences between the patients treated using the LT-CAGEŽ Device/INFUSEŽ Bone Graft combination versus the traditional spinal fusion techniques?
Dr. Zdeblick: The patient that were treated with INFUSEŽ Bone Graft/LT-CAGEŽ Device stayed on average one day less in the hospital perhaps because they could get up more easily to walk. They could move about more easily. Many of my patients were done on an outpatient basis, which I could never do when I harvested bone graft. The pain from the bone graft site is what keeps patients in the hospital and keeps them from returning to normal activity.
The preliminary results of the INFUSEŽ Bone Graft/LT-CAGEŽ Device clinical trials generated a lot of excitement among surgeons. This product is a tremendous advance. The last thing you need to do when you're treating back pain is create some other pain. By not taking a patient's bone graft, we don't create any other pain. We simply treat the back pain from the degenerative disc.
The information provided here is not a substitute for professional medical advice. All of the content is educational in nature and for general information purposes only, and is not a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified medical professional regarding any questions or medical conditions.
