Study: Surgeons’ Rosy Perception of ACDF Outcomes are Inaccurate

Spine surgeons can be a tad sanguine at times.

Kenneth A. Pettine, M.D., a spine surgeon at The Spine Institute in Loveland, Colo., used to count himself among that bullish bunch. Then he conducted a study of anterior cervical decompression and fusion (ACDF) procedures and he realized just how bouyant he and his colleagues could be sometimes.

Results of a meta-analysis of Class I and Class II data for ACDF showed a 10 percent revision rate and a 70 percent clinical success rate. Pettine presented his findings at the North American Spine Society’s 25th Annual Meeting in Orlando, Fla., earlier this month.

“If you ask most spine surgeons what the results are of a one-level anterior cervical fusion, typically they would answer that it’s a 95 percent operation; that 95 percent of patients have excellent results, and fusion rates are over 95 percent,” he said, adding that he had the same misconception of results before conducting the study.

“There is a perception that this is such a great operation,” Pettine continued. “I’m not saying it’s an awful operation. We’re just presenting data that [say] it’s certainly not 95 percent.”

It’s not even close. Pettine and his colleague, Lukas Eiserman, senior director of development, Advanced Technology, at NuVasive Inc., a San Diego, Calif.-based designer and developer of spine treatment products, analyzed Class I and Class II data from five U.S. Food and Drug Administration investigational device exemption studies involving ACDF.

The research conducted by Pettine and Eiserman included studies on the BAK-C and Affinity cages filled with locally reamed autogenous bone compared with intervertebral allograft without plating. The research also included separate studies on the Prestige, ProDisc and the Bryan artificial discs compared with intervertebral allograft with plating.

The five combined studies provided a sample of 1,154 single-level ACDF patients; 562 patients were fused with a stand-alone interbody cage, and 592 were fused with an interbody allograft along with a titanium cervical plate. The researchers compared the measures common among all of the trials: the Neck Disability Index, reoperation rate, neurological success rate and composite success rate.

After two years, the BAK-C patients experienced a 12 percent reoperation rate, while those who received the BAK-C control allograft without plating experienced a 17.5 percent reoperation rate, according to Pettine’s study results. Patients with the Affinity cage had a 9.2 percent reoperation rate, while patients given the Affinity allograft without plating experienced an 18.1 percent reoperation rate.

The overall reoperation rate of ACDF without plating was 12.7 percent, according to Pettine’s research. For the allograft with plating studies, the Bryan control group reported a 4.1 percent reoperation rate, the Prestige control group experienced a 19.9 percent reoperation rate and the ProDisc control group showed an 8.5 percent reoperation rate. The overall reoperation rate for ACDF with plating was 9.5 percent.

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

Pettine said his study plays two important roles: it represents accurate ACDF results (however disappointing they might be to those upbeat spine surgeons) and it emphasizes the significance of examining literature. “It’s kind of like blog sites—you know they’re not all equal,” he said. “You can get information on the Internet, and depending on the source, it’s either better information or it’s not as good. There’s no question that Class III and Class IV data are not as good as Class I data.”

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