Trial findings highlight gains of lumbar disc replacement

Investigators reported two-year follow-up data with the SB Charité lumbar disc.

Issue: Issue 3 2004

AAOS [logo] SAN FRANCISCO — Two-year findings comparing the SB Charité Intervertebral Disc Spacer with anterior interbody fusion suggest that the disc is a viable and potentially more effective treatment option for patients with severe lumbar disc degeneration.

In a presentation at the Scoliosis Research Society Specialty Day Meeting, Paul C. McAfee, MD, outlined details of the first 375 consecutive patients enrolled in a level 1 comparative, prospective, randomized multicenter study with two-year minimum follow-up for one-level disc pathology. One-third of the patients were treated with anterior interbody fusion using the BAK Interbody Fusion Device (Zimmer Spine); two-thirds of the patients were treated with disc replacement using SB Charité (DePuy Spine).

Fifteen U.S. sites treated patients in the study. All 6900 preoperative and postoperative x-rays were sent to a Baltimore facility for digitization and correction of magnification factors.

According to McAfee, an orthopaedic spine surgeon at St. Joseph’s Hospital in Baltimore, U.S.A., the Charité was significantly more effective than the BAK in restoring the height of the collapsed disc space (P<.001). The initial disc space height at the L5-S1 operative level started at 5.2 mm (mean) ±1.44 mm and immediately postop that increased to 13.5 mm (mean) ±1.18 for the Charité cases. Patients who received the BAK at L5-S1 started at an initial disc space height of 5.9 mm ±1.74 mm and increased to an immediate postoperative disc space height of 11.9 mm ±2.07 mm.

There was less subsidence with the Charité disc replacement at the two-year follow-up (P<.001), McAfee said. Also, approximately 83% of the 276 consecutive patients who received the Charité were identified as having “ideal” placement that investigators defined as disc insertion within 3 mm of optimal placement in both planes.

McAfee said that one of the keys of the ongoing study was the validation of the control group. The BAK fusion rate was 94% and was comparable to the published results of Kuslich et al.

“The study results seem to show that the disc replacement patients did statistically better and recovered faster than those who received lumbar fusion, including the Oswestry and Visual Analog Scale scores,” he said. “Patients with artificial discs recovered faster, returned to work sooner and spent less time in the hospital than those who received a fusion.”

McAfee said artificial lumbar discs are especially appealing in their ability to prevent or reduce the severity of progressive adjacent segment disease.

Developed at the Charité Clinic in Berlin in the mid-1980s, the SB Charité is currently used as an investigational device in select U.S. facilities, but it has received the CE mark in Europe and is being used in Europe, Asia, Canada, Africa, Australia and Latin America.

Dr. McAfee has a financial interest in a product cited in the article and is a paid consultant to DePuy.

For more information:

McAfee P, Cunningham B, Holtsapple G, et al. A prospective randomized FDA study of the Charité disc replacement – a radiographic outcome analysis of 276 consecutive patients. #11. Presented at the Federation of Spine Associations Specialty Day. March 13, 2004. San Francisco.