Motion preservation at two cervical levels may make more sense than fusion

SAN FRANCISCO — The safety and effectiveness of cervical total disc replacement was maintained at 5-year follow-up at levels seen in studies of the same prosthesis with shorter follow-up, regardless of whether the prosthesis was implanted at one or two levels of the spine, according to study data presented here.

Results of one-level anterior cervical discectomy and fusion (ACDF) were comparable to those of one- and two-level cervical total disc replacement (CTDR) in the 5-year results, but not to those of two-level ACDF, according to Hyun W. Bae, MD, who presented the study results at the North American Spine Society Annual Meeting.

Hyun W. Bae

The prospective, randomized, multicenter, concurrently controlled trial comprised two treatment arms. Two hundred forty-five patients were enrolled in the one-level procedure arm of the study, where they were randomly assigned in a 2:1 fashion to either CTDR or ACDF. Overall, there were 164 CTDR patients who received the Mobi-C prosthesis (LDR Medical; Troyes, France) and 81 ACDF patients.

The study’s two-level arm included 330 patients randomly assigned on a 2:1 basis to either CTDR or ACDF.

“Of note, at 5 years, our follow-up rate was 88.5% in the CTDR group and 83.1% in the ACDF group,” Bae said.

Bae and colleagues used multiple measures to assess the outcomes of both procedures performed in the one-level and two-level settings, including disability, neck and arm pain, patient satisfaction with the procedure, complications, reoperations and other factors.

Neck Disability Index scores showed one-level CTDR and one-level fusion were about equivalent, as was two-level CTDR, according to Bae.

However, function with the two-level ACDF dropped off as the follow-up reached closer to 5 years.

“Two-level fusion does seem to be a different operation in terms of function,” Bae said, noting in some respects two-level fusions lag behind the other three procedures.

“Although, if you look it as a whole, all these operations are very good, meaning that they still rank with a 90% satisfaction rate,” he said.

Complication rates and rates of adverse events were low in the study at about 5% for the three most successful procedures studied, according to Bae. — by Susan M. Rapp

Reference:

Bae HW. Paper #80. Presented at: North American Spine Society Annual Meeting. Nov. 12-15, 2014; San Francisco.

Disclosure: Bae receives royalties from Stryker, NuVasive, Zimmer, Biomet, has stock ownership in DiFusion, Spinal Restoration, and has private investments in Ascent, is a consultant to Stryker and has teaching/speaking arrangements with Synthes.