Prodisc® Artificial Disc Study

NeuroCare Network neurosurgeons will participate in the clinical investigation to compare the safety and effectiveness of the PRODISC® total disc replacement to spinal fusion surgery in the treatment of discogenic pain associated with degenerative disc disease (DDD) in the lumbosacral spine in the L3 – S1 vertebral segments. There will be separate study arms for one and two level cases. The total duration of this study is expected to be approximately 4 years.

Qualifications for inclusion in the study:

Patients must have the following conditions and meet the following criteria to be enrolled in this study.

1. Be between the ages of 18 and 60 years old;
2. Have tried conservative treatment unsuccessfully for at least 6 months;
3. Have at least a minimum level of pain and disability, as measured on questionnaires you have taken;
4. Be able to do everything the study requires as decided by the surgeon; and
5. Have signed informed consent.

Exclusion Criteria:

Patients who have any of the following conditions or meet any of the following criteria are excluded from participating in this study:

1. Have a known allergy to titanium, polyethylene, cobalt, chromium or molybdenum;
2. Have diseased discs at 3 levels or 2 non-neighboring levels;
3. Have had fusion surgery before;
4. Have back or leg pain because of another problem or an unknown cause;
5. Have bones which are unacceptably weaker than normal;
6. Have bone or metabolic diseases determined by the surgeon to be unacceptable;
7. Are extremely over weight;
8. Are currently pregnant or interested in becoming pregnant in the next 3 years;
9. Currently have an infection;
10. Are using drugs that may interfere with bone or tissue healing as decided by the surgeon to be unacceptable;
11. Have rheumatoid arthritis or other autoimmune disease, systemic disease including AIDS, HIV, Hepatitis;
12. Have unacceptable scoliosis, or cancer or a malignancy unless otherwise determined by the surgeon.

Degenerative disc disease and current treatments

Degenerative disc disease (DDD) refers to a syndrome in which a degenerating disc causes chronic back pain, which significantly impacts on an individual’s ability to function. The condition is most commonly diagnosed in the Lumbosacral spinal segments L3 – S1. The condition often starts with an injury to the disc space. The injury weakens the disc and creates excessive motion at the corresponding vertebral level. Over time, the segmental instability and associated neurological compromise combined with ongoing inflammatory processes that occur in and around the disc produce low back pain. The reparative processes in the disc are poor and the painful symptoms can become chronic.

For some people, DDD can be successfully treated with conservative care usually anti-inflammatory drugs combined with physical therapy. Most patients will experience low-grade, continuous but tolerable pain that will occasionally flare (intensify). Stronger therapies, such as oral steroids or epidural injections, are often prescribed to treat severe flare-ups. Surgical procedures including discectomy and intradiscal electrothermal coagulation (IDET) or annuloplasty may also be attempted.

For patients who are unable to function because of the pain, or who are dissatisfied with their activity limitation, lumbar spinal fusion surgery is an option. Lumbar fusion for back and leg pain caused by degenerative disc disease is considered an option for patients who:

a.. Have failed to improve after extensive conservative treatment (such as physical therapy, medications); or
b.. Continue to have back and leg pain that limits their ability to function.

There are a number of surgical procedures available to the surgeon that can be used to achieve fusion of the lumbar spine. The surgery can be done from the front, an anterior lumbar interbody fusion (ALIF), from the back, a posterior lumbar interbody fusion (PLIF) or posteriolateral fusion (PLF) or some combination of these procedures.

Additionally, various medical devices (rods, plates, screws, cages, bone dowels, etc.) and various bone graft materials (autograft, allograft, bone graft substitutes or a combination of these) may be used to augment the fusion procedure.

The surgeon, based on a number of considerations, selects the surgical techniques, implants and bone graft materials to be used. These considerations include the patient’s demographic characteristics (including age, weight, gender); the number of vertebral levels being fused and the stage of the disease process to name a few. Based on these factors and his/her personal experience, the surgeon decides which surgical procedures, implants and bone graft materials are most appropriate for that patient.

At this time, the state of the art of spinal fusion surgery involves many different combinations of techniques, devices and bone grafts. Over the last 5 years the options available to surgeons have expanded rapidly and at this time there is no standard procedure for any given fusion indication.

Theoretically, fusion surgery is effective because it stops the motion at a painful motion segment and allows for the removal of the disc that in most cases is the primary source of the pain. As the number of levels to be fused increases, the probability of a successful fusion decreases dramatically. Only in extreme cases would most surgeons recommend or even offer a three or four-level fusion.

If you have questions about artificial disc replacement, e-mail us!

June 9, 2002

Neurosurgeon Heading Tyler’s Investigational Study ET Doctor Traveling To France For Cutting- Edge Procedure

By Marvin Ellis, Staff Writer, Tyler Courier Times/Tyler Morning Telegraph

Artificial discs have been implanted in 14 East Texans in an investigational study since October…but the amazing twist concerning this back procedure is the neurosurgeon heading the program in Tyler is preparing to go under the knife for the same operation.

Dr. Guy O. Danielson III, MD and president of NeuroCare Network, said, “There is a 50--50 chance I will be able to show you an X-ray with my name on it with one of these discs in my back.”

He said during an interview with the Tyler Courier Times—Telegraph last week about the PRODISC surgery for reconstructive surgery for low back pain, “I will have to go to France where this surgery was developed to make sure I have the artificial disc surgically implanted. Here in the United States I would have to enroll in the randomized study and might not get it.”

Danielson said he was being evaluated for back surgery by the developer of PRODISC, Dr. Thierry Marnay of France.

While being questioned about recommending the investigational study to East Texans, Danielson responded, “I have a problem this procedure is designed to treat and I have been living with it for years. It came to a head about two months ago when I was skiing in Canada and I started having pain in my back. It has progressively gotten worse.”

The 59-year-old Oklahoma City native added, “I got a MRI scan and had Dr. Aaron Calodney do some injections. It has helped a little, but when I went over to France in May for the disc conference, I took my MRI scan to show to Dr. Marnay.”

Since then Danielson has also sent CT scans for Marnay to check. “I am trying to make up my mind in the next few weeks and a lot depends on Dr. Marnay’s evaluation.”

Danielson praised the work he has witnessed in the study in the United States and surgeries done in France. “This procedure is going to be one of the most important technological advances in the last 10—15 years in our field.” Back pain is second only to the common cold as the No. 1 ailment in the U.S.

Tyler was the second place in the United States to Participate in the study, with Dr. Marnay assisting the first two operations in the Rose City. The first three were done in Dallas the day before.

The 1968 graduate of University of Oklahoma School of Medicine said the investigational study will include 250 patients with a one-level disc implant, and 250 patients with two-level implants. “We will average about 10 percent of the study in the United States,” he said.

So far in Tyler, 13 East Texans have had one-level implants, while only one has had the two-level disc surgery. Implants are made from cobalt chrome and high-density polyethylene.

“Tyler attracts a lot of people who have spine problems, and we have been a center in past studies. Sites that have been asked to participate in this study are highly regarded,” he said. Other hospitals in the United States conducting trials include two in New York City and one each in Philadelphia, Chicago, Memphis, St. Louis, Los Angeles, San Francisco, San Diego and Dallas.

Danielson said four or five patients will have two-level disc implants in the next two or three weeks. “We had to have 10 with one-level implants completed before doing the two-level.”

The randomized study begins with patients who need disc fusion, which is the last resort by back doctors. Danielson said conservative back options are always considered before doing surgery. “Their pain is so bad, it is the fusion or investigational disc…this is not a study about a person who has a little ache or pain in their back so they can play 36 holes of gold rather than 18 in a day…they are in the fight of their lives against back pain.”

“So patients have to be willing to have fusion before they are considered for this study. Just before surgery, we call FDA (Food and Drug Administration) at a computer which randomizes who gets the artificial disc. I generally tell the patient before we go into surgery what has been chosen.”

Danielson said the artificial disc was developed after replacements for the hips and knees were developed. “it gives normal amount of mobility, and so far our patients have been doing well, some are doing phenomenally well.”

He said they have not had enough patients in the study to analyze and make a scientific statement, “but it has been very impressive. My responsibility as an investigator means I can’t sound like I’m trying to sell this thing…what I can tell you , that probably, number 1, we are encouraged and number 2, it does appear that patients that have had this in Europe have a quicker recovery…all our experience in the states mirrors what the Europeans have found to be true.”

He said East Texans receiving the artificial disc generally go back to work in half the time than patients with fusion.

Dr. Marnay started with 70 disc implants about 11 years ago and follow-up investigation showed 92.7 percent of the patients had a high percentage of improvement.

Danielson said the surgery is similar to fusion, except they used a specialized chisel to cut in to the spine to insert the disc. The implant’s “teeth” keep it in place in the spine, with a plastic insert similar to those used in other joint replacement surgery.

He said, “What impresses me is that we have a new way of thinking about helping people who have these severe problems with back injuries and back pain…we always have known as we get older this is going to be a problem and we have been pretty comfortable in doing a fusion on an older person, but those in their 20s and 30s we have been quite reluctant to talk about a spine fusion because of the long-term effects.”

“What this has done is change our thinking about how we can help some of the younger patients. Some enrolled in this study in their 20s…when you think about the potential years of a person’s life that you can impact…a person who is having a problem with their back in their 20s is sure to continue to have problems the rest of their lives, and when they are in the prime of their lives, raising their families, they have a lot of important things to do.”

“If they are disabled at that age, it’s a problem they are going to live with a long length of time, so this is going to be one of the most exciting and dramatic parts of it…it’s being able to take appropriate technology to treating some of the people when they really need it the most,” he concluded. To check about enrolling in the study, call Tonya Fitzgerald, clinical research coordinator, or Jennifer Jones, clinical research assistant, at (903) 597-3472