Final Long-Term Reporting from a Randomized Controlled IDE Trial for Lumbar Artificial Discs in Single-Level Degenerative Disc Disease: 7-Year Results
Kris E. Radcliff, Jack E. Zigler, Ernest Braxton, Glen Buttermann, Dom Coric, Peter B. Derman, Rolando García, Anton Jorgensen, Nicole Ferko, Aaron Situ, James J. Yue
Abstract
<h3>ABSTRACT</h3> <h3>Background:</h3> This study compared 7-year safety and efficacy outcomes of activL and ProDisc-L lumbar total disc replacements in patients with symptomatic, single-level lumbar degenerative disc disease (DDD). The objectives are to report 7-year outcomes of the trial, evaluate the outcomes for patients lost to follow-up, and determine whether early outcomes predict long-term outcomes. <h3>Methods:</h3> This was a prospective, multicenter, randomized, controlled investigational device exemption study. Eligible patients with symptomatic, single-level lumbar DDD had failed ≥6 months of nonsurgical management. Patients (<i>N</i> = 283) were randomized to receive activL (<i>n</i> = 218) or ProDisc-L (<i>n</i> = 65). At 7 years, data were available from 206 patients (activL, 160; ProDisc-L, 46). Logistic regression models were fit to predict 7-year outcomes for patients lost to follow-up after 2 years. <h3>Results:</h3> At 7 years, the activL group was noninferior to the ProDisc-L group on the primary composite endpoint (<i>P</i> = .0369). Both groups showed significant reductions in back/leg pain severity and improvements in disability index and quality-of-life relative to baseline (<i>P</i> < .0001). In both groups, opioid use was significantly reduced at 7 years (0%) relative to baseline (<i>P</i> < .01), and the overall reoperation rates were low (4.6%). activL patients showed a significantly better range of motion (ROM) for flexion-extension rotation than ProDisc-L patients (<i>P</i> = .0334). A significantly higher proportion of activL patients did not report serious adverse events (activL, 62%; ProDisc-L, 43%; <i>P</i> = .011). Predictive modeling indicated that >70% of patients (depending on outcome) lost to follow-up after 2 years would show clinically significant improvement at 7 years if improvements were achieved at 2 years. <h3>Conclusions:</h3> The benefits of activL and ProDisc-L are maintained after 7 years, with significant improvements from baseline observed in pain, function, and opioid use. activL is more effective at preserving ROM than ProDisc-L and has a more favorable safety profile. Improvements in other primary and secondary outcomes were similar between both disc designs. <h3>Level of Evidence:</h3> 1.