13.jpgThe FDA recently (Dec 12, 2007) approved ProDisc-C for cervical vertebra use. They first approved ProDisc-L for lumbar-vertebra use in Aug 2006.

ProDisc was designed in the late 1980’s by a French Spinal Orthopedic Surgeon name Thierry Marnay. Marnay implanted this artificial disc into 64 patients in the early 90s and almost a decade later these patients were studied to determine the long-term results of implantation. Three patients had died from unrelated causes, but the remaining 58 were studied extensively at 7-11 year follow-ups. All implants were intact and functioning. There had been no implant removals, revisions, or failures.

There was no evidence of subsidence (sinking or settling in bone) on follow-up radiographs compared to the peri-operative films, as reported by the operating surgeon as well as by an independent US Orthopaedic spine surgeon.

A significant (99.99% confidence) reduction in patient-reported back pain and leg pain was identified. 92.7% of these patients were “satisfied” or “extremely satisfied” with the procedure.

Two-thirds of these patients had single vertebra implants while one-third had two vertebra replaced. There was no outcome difference between the 1 and 2 level ProDisc implantations.

During follow up, there were no device-related safety issues, no untoward effects, no complications and no adverse events.

07.jpgProDisc is made of metal endplates made of a cobalt chromium molybdenum alloy (CoCrMo). The convex bearing surface, snap-fit into the inferior end plate, is made of ultra-high molecular weight polyethylene (UHMWPE). The artificial disc is attached through a large central keel and two spikes on each endplate. Physiologically, the ProDisc matches the range of motion in flexion, extension, axial rotation, and lateral bending as a normal spine.

From these positive results, the ProDisc has been implanted in over 8000 patients in Europe since December 1999. A multicenter FDA study was started in the United States in October 2001. The first ProDisc in the United States was implanted at the Texas Back Institute on October 3, 2001. Nineteen study centers participated in the prospective randomized study, comparing the ProDisc to the current standard treatment of a 360° (front and back) fusion using allograft in the intervertebral space and pedicle screws with autograft posteriorly.

ProDisc is the only one of the artificial discs undergoing FDA trials that is being investigated for multiple level lumbar disc disease. Other disc replacement devices include: Maverick, Flexicore, Kineflex.

The two level study arm completed enrollment in November 2003. Continued Access in this arm began in January 2004, where a limited number of patients may be treated at study sites with two-level ProDisc surgery as long as they meet the original study criteria, and continue follow-up for collection of safety data.

Thanks for the input and collaborations with Dr. Sue Snyder. 

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