Medical Device Daily Associate

Johnson & Johnson's (J&J; New Brunswick, New Jersey) nearly two-year monopoly on the artificial spine disc market has been broken with the report by Synthes (West Chester, Pennsylvania) that its ProDisc-L device has been approved by the FDA for use in single-level disc replacement for treatment of lower back pain in a market that investors see as a potentially huge.

The new device will compete with J&J unit DePuy Spine 's (Raynham, Massachusetts) Charité artificial disc – which was the first such device to be approved for sale in the U.S. in October 2004 (Medical Device Daily, Oct. 28, 2004) – as an alternative to spinal fusion surgery for as many as 25% of the 220,000 Americans who undergo fusion annually.

Texas Back Institute (TBI; Plano, Texas) surgeon Jack Zigler, MD, who performed the first ProDisc implant in the U.S. in October 2001, told Medical Device Daily that the single-level approval is an important milestone, but noted that two-level surgeries are an important addition to the arsenal that should be available soon. “There's a reasonable number of patients who have symptomatic two-level disease.”

He noted that a two-level arm was incorporated into the U.S. clinical trial for the ProDisc in January 2004, about four months after the sing-level arm of the study began enrollment. “The two-level arm lags nine to 12 months behind the one-level [arm].”

TBI also is involved in FDA investigational trials for Synthes' ProDisc-C, which is designed as an artificial cervical disc to treat neck pain. In addition, there are four additional artificial disc devices under FDA investigation at the TBI Center for Spine Arthroplasty at this time, and that institution also was involved in the U.S. clinical trials for the Charité.

Developed by a French spine surgeon, the ProDisc total disc replacement has more than 15 years of clinical follow-up in Europe.

In the U.S., TBI served as the highest enrolling site among the 19 centers in the U.S. that conducted FDA-approval trials of the device, comparing its clinical effectiveness and safety to 360-degree fusion at any of the lowest three lumbar disc levels.

According to Zigler, there are several noteworthy differences between the ProDisc and Charité. One important difference he said is the fact that L3-4 patients can have a ProDisc “on-label,” whereas the Charité is only approved for use in L4-5 and L5-1 procedures.

Zigler said from his experience, the instrumentation of the ProDisc “is much better” than that of the Charité. “It's more streamlined, it uses a shorter width, it's easier to access the midline with it and it's easier to see the disc space around the instruments than with the Charité.”

Two surgeons work together in a standard artificial disc implantation procedure. A general surgeon appro-aches the spine through an incision in the abdomen and carefully moves blood vessels and internal organs out of the way to provide access to the spine. A spine surgeon then removes the damaged disc to create a space between two vertebrae for the implantation of the artificial disc, which is done using fluoroscopic guidance. Generally, the procedure takes about 60 to 90 minutes for a single level.

The issue of reimbursement is sure to be a sticking point for Synthes as it has been for DePuy, as insurers have continued to classify that disc as an experimental device, and many refuse to cover the cost of the implant procedure, which can cost more than $10,000 per disk and several times that amount in hospital and doctors' fees.

Zigler expressed some frustration at this obstinacy. “You have two unbelievably scientifically valid studies [for the Charité and ProDisc] . . . that are presented to insurance companies and they're still saying no.” He noted that as far as he knows, this is the first time that the insurance companies “have decided to dig their heels in and decide what patients get, and it kills me because that decision should be between patients and their doctor.”

He said doctors already know there are problems with spinal fusions and while, as insurers argue, there is not as much long-term data on artificial discs since they have not been in the surgical arsenal as long, “It's certainly unlikely they'll be worse than fusions, so why not give people the chance” to try the artificial disc.

Zigler also argued that the cost differential between the fusion and disc procedures is negligible and in fact the pricing for the disc “was probably made to be similar to or a little bit less than the equivalent fusion per level.”

Although fusions relieve back pain, they may significantly limit range of motion and place extra stress on discs above and below the fusion site. Fusions usually require patients to wear a back brace for several months and require an extended period of rehabilitation, whereas ProDisc-L implant patients require only a short period of soft bracing and a quicker return to normal function. About 20% of fusion patients require additional surgery for an adjacent disc problem within 10 to 15 years.

Zigler said that while it is now difficult to get an artificial disc covered by insurers, he believes that eventually the trend will be reversed. “I think there'll be a time where in an active, working person, we'll have trouble getting an approval for a fusion because the insurance companies are going to want us to do arthroplasty.”