Published 12/1/2010

ACDF results do not match perception

“If you ask most spine surgeons about the clinical results of a one-level anterior cervical fusion, typically they would answer that it’s a 95 percent operation—95 percent of patients have excellent results, and fusion rates are 95 percent or better,” Kenneth A. Pettine, MD, told members of the North American Spine Society. Dr. Pettine himself believed those statistics—until he did a meta-analysis of the published results.

“The perception is that this is a great operation,” Dr. Pettine said. “I’m not saying it’s an awful operation. We’re just presenting the data that it’s certainly not 95 percent.”

In fact, based on Level I and Level II data, Dr. Pettine found that anterior cervical decompression and fusion (ACDF) has a 10 percent reoperation rate and a 70 percent clinical success rate.

Using IDE studies
Level I and Level II data were available from five U.S. Food and Drug Administration (FDA) investigational device exemption (IDE) studies involving ACDF as the control procedure. Two studies compared two different types of interbody fusion systems filled with local reaming of autogenous bone versus intervertebral allograft without plating; three studies compared various artificial disks versus intervertebral allograft with plating.

In the first study, the BAK-C fusion system (Zimmer, Minneapolis, Minn.) had a 12 percent reoperation rate; the BAK-C control allograft without plating had a 17.5 percent reoperation rate. Reoperation rates in the second study were 9.2 percent for the Affinity cage system (Medtronic Sofamor Danek, Memphis, Tenn.) and 18.1 percent for the Affinity allograft control without plating. The overall reoperation rate of ACDF without plating was 12.7 percent.

The remaining three studies involved artificial disk systems. The reoperation rates for the ACDF controls were 4.1 percent, 19.9 percent, and 8.5 percent. The overall reoperation rate for ACDF with plating was 9.5 percent.

The five combined studies provided a sample of 1,154 single-level ACDF patients—562 patients fused with a stand-alone interbody cage and 592 fused with an interbody allograft along with a titanium cervical plate.

Thus, based on this analysis, the true result for a one-level ACDF is a 10 percent reoperation rate due to pseudarthrosis, adjacent level degeneration, or revision of the index surgical site, said Dr. Pettine. In addition, the clinical success rate was 70 percent.

The evidence base
This study plays two important roles, according to Dr. Pettine. First, it presents the real ACDF results. Second, this research emphasizes the importance of examining the literature.

Dr. Pettine is currently conducting a more expansive meta-analysis of seven Level I studies on allograft ACDF with plating, which he said is currently considered the U.S. gold standard for fusions.

Dr. Pettine’s coauthor for “Meta-analysis of Class I and II Data on Results of Anterior Cervical Decompression and Fusion” is Lukas Eisermann.

Disclosure information: Dr. Pettine—Medtronic, Paradigm, Spinal Motion, NuVasive; Mr. Eisermann—NuVasive.

Bottom Line

  • Spine surgeons generally believe that ACDF is more successful than the data indicate.
  • Based on an analysis of Level I and Level II data, however, ACDF has a 10 percent reoperation rate and a 70 percent clinical success rate.