Artificial disc may be a viable alternative to fusion for two-level disc disease

Two-year postoperative data from a randomized, multicenter trial published in the Journal of Bone and Joint Surgery (American) has revealed that worn-out adjacent discs in the lower back can be treated viably through the utilization of artificial discs.

The study’s lead author, Rick B. Delamarter, MD, noted in a Cedars-Sinai Medical Center press release that while previous studies have compared single-disc replacements with fusion, it is believed none others have evaluated the two forms of treatment for two contiguous discs.

The researchers worked with a cohort of 237 patients in a randomized, controlled trial reported in the abstract as being designed, for regulatory application purposes, as a non-inferiority study. The patients were categorized through blocked randomization into a 2:1 ratio of total disc arthroplasty patients to circumferential arthrodesis patients.

For evaluations, the researchers collected data through patient self-assessments, physical and neurological examinations, and radiographic examinations. These data were collected preoperatively, 6 weeks postoperatively, and 3, 6, 12, 18, and 24 months postoperatively.

Study results

The researchers reported in the abstract that 87 (58.8%) of the 148 patients who underwent total disc replacement could be classified as a statistical success, compared with 32 (47.8%) of the 67 patients in the arthrodesis group. Mean Oswestry Disability Index scores in both groups significantly improved from baseline, with mean percentage of improvement for the total disc replacement group being reported in the abstract as significantly higher than that in the arthrodesis group.

The authors also found a 15-point or greater improvement in Oswestry Disability Index scores from baseline in 109 (73.2%) of the patients in the total disc replacement group, as opposed to 37 (59.7%) in the arthrodesis group. SF-36 scores and visual analog scale scores were also reported as significantly better for the total disc replacement group when compared with the arthrodesis group at the 24-month mark.

At the 24-month postoperative follow-up, 111 (78.2%) of the patients in the total disc replacement cohort reported they would have the same surgery again. Thirty-six (62.1%) of the arthrodesis cohort made the same assertion.

“Overall, 24 months after surgery, patients in both groups had less pain and were able to reduce their use of medication, but the percentages were higher in the disc replacement group,” Delamarter stated in the release. “Seventy-three percent of disc replacement patients met the study’s pain improvement criteria, compared with less than 60% of the fusion patients. Of these, only 19 percent in the disc replacement group continued to need narcotics for pain, compared with 40% in the fusion group.”

Reference:

Delamarter R, Zigler JE, Balderston RA, et al. Prospective, randomized, multicenter Food and Drug Administration investigational device exemption study of the ProDisc-L total disc replacement compared with circumferential arthrodesis for the treatment of two-level lumbar degenerative disc disease: Results at twenty-four months. J Bone Joint Surg Am. 2011;93:705-715. doi:10.2106/JBJS.I.00680.

Disclosure: One or more of the authors received outside funding or grants in excess of $10,000 from Synthes Spine. In addition, one or more of the authors or a member of his or her immediate family received payments or other benefits in excess of $10,000 or a commitment or agreement to provide such benefits from commercial entities (Synthes Spine, Spine Solutions).

http://www.csmc.edu/

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