A research team led by Richard Guyer, MD, of Texas Back Institute in Plano, compared the Kineflex-L Disc to the CHARITE artificial disc for lumbar disc replacement procedures and published their findings in Spine.
Article authors also included Kenneth Pettine, MD, Jeffrey S. Roh, MD, Thomas A. Dimming, MD, Domagoj Coric, MD, Paul C. McAfee, MD, and Donna D. Ohnmeiss, Dr. med. The data was derived from 457 patients who received surgery at 21 sites. There were 261 who received the Kineflex-L Disc and 196 who received the CHARITE disc.
All patients were treated nonoperatively for at least six months prior to surgery. Here are five things to know about the artificial discs examined in this study:
1. The Kineflex-L Disc has a metal-on-metal design anchored with kneels while the CHARITE artificial disc is metal with a polyethylene core and teething for anchoring. The researchers found no significant difference between the two groups when comparing:
• Operative time
• Blood loss
• Length of stay
"This prospective, randomized, controlled study comparing two TDRs, the first to the authors' knowledge, found the devices produced very similar clinical outcomes," the study authors concluded. "Both groups improved significantly by six weeks postoperatively and remained improved throughout follow-up with a high patient satisfaction rate."
2. Both groups reported significantly better Oswestry Disability Index and visual analogue scale scores. There was no difference between the groups in these scores. The success rate was also similar; 68.1 percent for the Kineflex-L and 67.4 percent for the CHARITE disc. Disc replacement could have similar or better outcomes when compared with spinal fusion as well. The North American Spine Society recently released coverage policy recommendations for several procedures, including lumbar artificial disc replacement:
"There have been two and five year follow-up studies published that demonstrate results that are at least equivalent to spinal fusion for discogenic low back pain. The procedure itself is technically challenging and a body of evidence exists that informs us of the technical pitfalls to be avoided. Proper training and institutional support is required." The coverage policy recommendations note there is only one artificial disc replacement prosthesis available in the United States today and others are going through FDA trials.
3. After the 24-month follow-up, the patient satisfaction was also similar and high. For the Kineflex-L group, patient satisfaction was at 94.1 percent, compared with 91.9 percent for the CHARITE disc.
4. There was a slightly higher reoperation rate for the Kineflex-L group when compared with the CHARITE disc group; 10.3 percent reoperation for patients with Kineflex-L compared with an 8.4 percent reoperation for the CHARITE disc. A separate study examining the 10-year results of total disc replacement using the CHARITE disc found good clinical outcomes; 89.6 percent returned to work — including 77.8 percent who had hard labor employment — and 90.6 percent of the implanted devices were still mobile.
5. An analysis of the emerging disc replacement market warns that other emerging markets, such as annulus repair and nucleus repair and replacement, could begin to limit growth among artificial disc replacements. Surgeons continue to experience difficulty receiving clearance for lumbar artificial disc procedures, although cervical disc arthroplasty is becoming more accepted among surgeons and payers.
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