Last week I caught up with Dr. Fred Geisler at AANS in New Orleans to discuss artificial disc clinical trials and surgeon adoption of artificial discs. Throughout the week, Dr. Geisler led the Academy as the principal thought leader on the subject of artificial lumbar discs.
Dr. Geisler is a recognized international expert in spine and degenerative disc disease and he enjoys a worldwide reputation in the area of developing new, innovative procedures in spinal surgery. Dr. Geisler is a leading authority of the motion-preserving artificial disc and was an investigator in the Charité artificial disc clinical trial.
Dr. Fred H. Geisler, MD, PhD.
JM: How should an artificial disc IDE be designed? What is the ideal control?
FG: There was the past and then there is now. In the past, discs had to be randomized against fusion. People have argued that the only other choice you would have is to randomize against conservative care. But, of course, one entrance criterion is that you have to fail conservative care to get into the study. So it is self-contradictory to randomize against doing what you know has already failed. If you want to randomize against fusion, your choice becomes one of the ALIF procedures, the BAK or someone else's threaded cage so that you are not confounded by the muscle splitting of the back. That would make your study clean. One thing about the Charité study that is important is how clean it was. The approach was identical in both for both the motion preserving device and the control.
JM: I understand that SpinalMotion's Kineflex artificial disc will be randomized against the Charité as its control.
FG: The FDA requires you to randomize against something that has been FDA approved so until the Charité was approved there was no other disc to randomize against. Since October 2004, not only are studies going to be randomized against the Charité, but they basically would have to be. This is because before a device is FDA approved, as surgeons, you don't have to tell the patients about treatments that are experimental or not approved mainly because there is no registry. If you take the example of cancer, if I had to disclose every treatment anywhere in the United States, there's no way I could do that because they are not registered. I may tell them about places theoretically I know about, but there is no way that could be comprehensive. Now, once a therapy becomes FDA approved, I am then obligated to offer that as an option.
So if I was doing anybody's motion study now randomizing against fusion, because the Charité is approved I could say "you can be randomized here" with a 1/2 or 1/3 chance of getting something you don't want or you can go across the street and just get one. So it would be almost impossible to enter patients in that kind of a study. Whereas the Kineflex study is going to be randomized against the Charité, by doing such the patient would have one device over another and patients would consider them equivalent. So the patient is getting the total disc replacement and they are just agreeing to the follow up period which they were going to want to do anyway and it becomes a very doable study. In fact, I will be signing up for the Kineflex study.
JM: Now that the Charité has been approved for several months, what is happening in the field?
FG: The physician enthusiasm is huge - even unprecedented - as far a new medical device goes. The IDE surgeons were very cautious about distributing information and, unlike other products that go out with a brochure and a laser pointer, we wanted training because this is fundamentally a new thing. It turns out Johnson & Johnson (DePuy spine) has stepped up to the plate. They established the training in Cincinnati at the Endo Institute that J&J owns. We reckon that 1,200 - 1,400 surgeons have gone through the training which is a one-day course that goes over the IDE, hands-on techniques, etc. There's one IDE surgeon there, two other surgeons who have placed the disc so that the trainees can get all their questions answered. They not only have in-depth discussions, but case presentations as well.
JM: That's potentially a significant number of "case capacity" if you multiply the surgeons trained by their case volume.
FG: That's right and there are even 1,000 more surgeons who have signed up for the course and I believe it's booked through November. I suppose the J&J folks would have a more accurate figure on that. The physician interest is simply huge and I cannot think of any other product that has this kind of interest. J&J will not distribute the product, unless you have gone through this training, however. Now some of the people going through the training because they want to put the disc in and some are going so they'll know who to refer the patients to. For sure, J&J is not telling these doctors that this is easy or that anyone can just do this. In fact, one of my common comments to someone who comes back to me with certain questions is that "maybe this procedure isn't for you and you have to consider whether you have the skill set to do this".
JM: It is interesting that in Europe discs have been out there for years if not decades, but at the end of the day, perhaps 5% - 10% of the cases actually involve an artificial disc. Will the U.S. see the same type of market penetration?
FG: It depends on what the pool of cases involve. If all we are doing is converting fusion cases over it's a small percentage of the fusion cases that can be converted over. Several people [who deal with complex cases] have retrospectively gone back and looked through their cases have come back and said that "in fact, all my cases would be exclusions". Well, of course that's the situation because complex cases such as Grade III Spondy [Spondolysthesis] or Scoliosis are contraindications and if that's your whole practice you aren't going to buy many of these. So the vast majority of cases that will be done will be fusions not the type of motion technology we are talking about. Now that may not be true in ten years, however.
Let's note that there is a whole new pool of patients that are truly untapped which we think we will have very good luck with. These are patients who [for example] have had a standard discectomy where the radicular pain, the leg pain, etc. go away at first. Then about a year/year-and-a-half later they get nagging back ache, they can't lift things, can't play with their kids, can't run, etc. They can work, they can get around and so forth but they don't think they are normal, they know they are not normal especially for their age. They would have what we would consider a type of disability, but in their own minds it's a high level of disability especially for their own age - in some cases even in their 30's. Even I am older and I want to do those things for a long time! Traditionally in the past, we have been advising these patients not to get a fusion. Although [with a fusion] we will fix these problems on that very day, because these patients are young they run the risk of getting into that fusion cascade down the road - e.g. adjacent level problems. For total management over this person's life, the best we could do for them in the past was to tell them to live with it. This is now no longer true with the artificial disc. Now we can fix them.
JM: So artificial discs are really a new place in the continuum of care.
FG: Correct. The disc by being infinitely slippery - and we have finite element work that will be coming out on this - means that when you put it in the spine (e.g. L5-S1) it actually decreases the forces on L4-L5, but if I fuse... I increase the forces [on L4-L5]. So the Charité acts as an offloader to the L4-L5 disc space and should retard or lessen the degenerative changes. I won't use the word "eliminate" because nothing is going to do that. I would point out that a fusion doesn't cause the adjacent level problem, it produces a tendency to increase forces that may enhance degenerative changes. So we now have a procedure we can offer somebody that will fix them and not start them in the degenerative cascade. Also if they have problems at the same level, we can fuse it later if that's necessary, of course, at that point we can never re-animate.
JM: Does that suggest there is an exit strategy with the artificial disc?
FG: If you needed to fuse it, you could fuse it, for example, if you have facet problems. The real disaster scenario or life-threatening revisions are if it throws out the front and gets to the vessels. It turns out that those are very rare.
JM: That's a good lead-in to the complication issue. What are the complications with lumbar discs and what can be done to ameliorate them?
FG: First and foremost is [surgeon] training. Second is knowing which patients to put [the disc] into. If you put it into a patient with a known contraindication, you should expect to get a bad result. That has occurred, but it is not a device problem it's a surgeon problem. Try asking an aerodynamic engineer to design an airplane that a pilot can't fly into a mountain! All you can do is tell those pilots... "don't start the engine". [laughter]
It's the same with a surgical technique. Suppose you want to get a new hip or knee. If you go to a guy who only does two a year, you are at the wrong spot. The figure [for artificial discs] you want is probably going to be around three a month. If your practice cannot support three a month, then you are probably better off referring your patients. I suspect in every economic area, as this shakes out, there are going to be a small number of all the people who actually call themselves spine surgeons who actually end up doing this procedure. This is a relatively contained market.
JM: Speaking of the economic issues, could you comment on reimbursement for the artificial disc?
FG: The reimbursement issue right now is just a mess. It's a mess for two reasons, one of which is that this is a new procedure so the insurance companies like to spend six months to a year deciding whether or not the procedure ought to be paid for. It's a part of their "don't pay for it or if you have to... pay late" thesis - e.g. they get an interest free loan. Then we have the issue of having the procedure assigned to a DRG this year. It now has a tracking code which we can consider totally prudent although we could say "not"! [laughter] In fact, I view all of these problems as transitory for the first year and then they will be gone.
I think this actually offers a good throttle valve on the training. What we didn't want is a thousand surgeons coming out of the box implanting ten of these a week because we wouldn't really be able to see what happens. Remember with any new technology, you had better do a slow rollout, figure out what the problems are, fix the problems and then continue on with life. Otherwise you could have some disasters and that's not what any of us want.
JM: Thank you Dr. Geisler.
FG: Thank you.
