One- vs two-level ACDF and disc replacement study shows trend of poorer results with two-level fusion

NEW ORLEANS — One of the first prospective studies comparing one- and two-level cervical total disc replacement with one- and two-level anterior cervical discectomy and fusion with up to 4-year follow-up shows a trend toward worse results with two-level fusion.

“Our study suggests that [anterior cervical discectomy and fusion] ACDF as well as [total disc replacement] TDR is a good operation from baseline,” Hyun W. Bae, MD, said during at the North American Spine Society Annual Meeting, here. “All of these patients had significant improvement. It does look like however, that there is a difference that we see in a sense that one-level and two-level, multilevel TDR, their efficacy is about the same. Its efficacy is about the same with a one-level fusion, regardless of reoperation rates. But, it does seem that we see a significant difference in the [neck disability index] NDI with the two-level fusion. So all good operations, but maybe the two-level fusion is not ideal or maybe could be improved upon.”

Hyn W. Bae

To investigate the safety and efficacy of one- and two-level ACDF and TDR and to compare the results of these procedures, Bae and colleagues used data from an investigational device exemption trial on the Mobi-C Cervical Disc Device (LDR; Austin, Texas). The one-level arm of the study included 225 patients with a 2:1 randomization favoring TDR, and the two-level arm included 330 patients who were randomized 2:1 favoring TDR. All of the patients were symptomatic for arm or neck pain.

Although the investigators found comparable NDI results at 4-year follow-up for one-level ACDF and TDR and two level-TDR, they discovered a significant difference for the two-level ACDF group. Although patient satisfaction and VAS scores for neck pain and arm pain showed no statistically significant differences between the groups, the study indicated a trend for worse results in the two-level ACDF group.

The investigators found no increase in the reoperation rate at 4 years between one- level and two-level TDR.

“However, when you look at the difference between one-level fusion, there is about a three-fold difference from the TDR group,” Bae said. “When you look at one-level fusion vs. two-level fusion, the reoperation rate does increase.”

There was no significant difference in adverse events related to the device for one- and two-level TDR. “However, when you start looking at one- and two-level fusion, you do see about a two-fold increase. So maybe two-level fusion is a different operation,” Bae said.

Reference:

Bae H. Paper #183. Presented at: North American Spine Society Annual Meeting; Oct. 9-12, 2013; New Orleans.

Disclosure: Bae receives royalties from Biomet, Stryker, Zimmer and NuVasive; is on the speaker’s bureau for Medtronic and Synthes; is a paid consultant for Medtronic, Zimmer and Synthes; has stock in Medtronic, Stryker, Orthovita, Spinal Restoration and DiFUSION; and receives research or institutional support as a principal investigator for Stryker, LDR, Johnson & Johnson, Orthovita and Medtronic.