VAS scores improved significantly in both groups, although improvement was significantly greater among Charite patients at all but the 24-month follow-up. Oswestry scores, which measure disability and function, followed a similar pattern.
Among Charite patients, 73% were satisfied with their treatment at 24 months, compared with 55% in the fusion group. When asked if they would choose the same treatment again, 69% of patients in the Charite group responded “definitely yes” and an additional 13% responded “probably yes,” compared with 52% and 13%, respectively, in the fusion group.
The device will be sold only to surgeons who have been trained by DePuy, and its Web site clearly states that patients should discuss with their surgeon whether they are candidates for the device, Mr. Christianson said.
Senior Writer Elizabeth Mechatie contributed to this report.
Other Cervical Arthroplasty Options
The Charité Disc System might have made it to the market first, but several other cervical arthroplasty options are in the developmental pipeline. Here's a look at some of those devices under investigation in the United States and elsewhere:
▸ Bryan Cervical Disc System (Medtronic Sofamor Danek) was approved for use outside the United States in 2002, and is now being investigated in the United States.
Results from a multicenter prospective study of the Bryan disk showed positive clinical outcomes in both single-level and bilevel treated patients with disk herniation or spondylotic changes at the C3-C7 levels with radiculopathy and/or myelopathy.
At 2 years, 62% of 98 single-level patients and 59% of 41 bilevel patients were “excellent” according to modified Odom's criteria, Jan Goffin, M.D., reported at the meeting. At 2 years, 86% of single-level patients and 96% of bilevel patients had preserved motion of more than 2 degrees.
However, paravertebral ossification was observed on x-ray in 4 of the original 25 study patients at 4 years. The use of NSAIDs postoperatively seems to reduce this phenomenon, said Dr. Goffin, of University Hospital Gasthuisberg, Leuven, Belgium.
There was no evidence of adjacent-level degeneration in 15 of the 25 patients, although long-term follow-up of more than 5 years will be necessary to address this issue, Dr. Goffin noted.
In a separate yearlong study of 90 patients with radiculopathy and/or myelopathy, 16 patients or 18% had signs of heterotopic ossification following implantation of the Bryan disk, reported Clarence Leung, M.B., London.
“In 10 patients, the artificial disk actually stopped moving at 1 year,” Dr. Leung said.
Based on the McAfee classification, six patients had grade III and IV heterotopic ossification, which was strongly associated with loss of movement. Older males were more likely to develop heterotopic ossification, he said.
▸ PCM cervical artificial disk (Cervitech) is not yet in U.S. clinical trials.
In a study comparing the Bryan system with PCM or porous coated motion disk, the Bryan group had longer incisions and operative times, compared with the PCM group, reported lead investigator Luiz Pimenta, M.D., of the University of Sao Paulo (Brazil).
Both groups had minimal blood loss of less than 50 cc.
Range of motion averaged about 8.3 degrees for flexion and extension in the PCM group vs. 4.5 degrees in the Bryan group.
Heterotopic ossification, which is strongly correlated with loss of movement, was present in 19% of Bryan patients, and in none of the PCM group.
In the Bryan group, there were no cerebral spinal fluid leaks, one anterior device migration, two postoperative cases of kyphosis, and three cases of fusion. By comparison, in the PCM group there were two intraoperative leaks, two device migrations, no kyphosis, and no cases of fusion.
▸ Prestige Artificial Cervical Disc (Medtronic Sofamor Danek) has been studied in clinical trials outside the United States and is currently in trials in the United States. In a small, prospective study, there was no statistical difference in any clinical outcomes at 1 year among 22 patients randomized to receive the Prestige disk and 48 patients who received anterior cervical diskectomy and fusion using cortical allograft and a cervical plate.
Patients treated with the Prestige disk showed improvement in all outcomes and maintenance of motion on x-ray, reported J. Kenneth Burkus, M.D., of the Hughston Clinic in Columbus, Ga.
The Bryan cervical disk was approved for use outside the United States in 2002.
The Prestige cervical disk is now being tested in U.S. clinical trials. Medtrinic Sofamor Danek