Wednesday, September 26, 2018 3:35 PM – 5:05 PM Preserving Spinal Motion: 89. Impact of range of motion on patient outcomes five years following lumbar TDR at L5-S1

Abstract

BACKGROUND CONTEXT Total disc replacement (TDR) is an alternative to fusion that preserves index level motion. A common misconception is that L5-S1 should be fused because TDR implants do not move at this level. Previously, we reported TDR at L5-S1 preserves motion at this level 5 years postimplantation, and that mobile core devices maintained better motion than constrained core devices. This study aimed to relate clinically significant improvements in patient outcomes (VAS and ODI) to the degree of motion at the L5-S1 index level. METHODS This is a post-hoc analysis of data collected from a large, multicenter clinical trial. Eligible patients were randomly allocated (2:1) to treatment with an investigational TDR device (activL) or a control TDR device (ProDisc-L or Charite). Range of motion (ROM), back pain (VAS) and Oswestry Disability Index (ODI) scores were available at the 5-year time point for 119 patients in the investigational group and 50 patients in the control group with L5-S1 TDR. RESULTS ROM was significantly better at L5-S1 at 5 years for patients implanted with the activL device (6.6° at baseline vs. 6.7° at 5 years, NS) than it was using the control devices (6.7°at baseline vs. 4.8°at 5 years, p=.002). Average ODI and VAS scores for back pain significantly decreased at 5 years from baseline for both groups. There were no differences in ODI or VAS scores between groups at 5 years, but each incremental improvement in ROM correlated with incremental clinical improvement. The percentage of patients demonstrating clinically significant (CS) improvements in ODI and VAS back pain scores (≥ 15% from baseline) at 5 years for every two degrees of ROM at L5-S1 was determined. For patients with 0-2° of motion, 81% and 86% of activL and control patients, respectively, demonstrated a CS improvement in ODI. CS improvement in ODI was observed in all patients with 8-10o of motion at L5-S1. Similarly, an average of 81% TDR patients with 0-2° of motion at L5-S1 demonstrated CS improvements in back pain. Compared to ODI scores, CS improvement for back pain was achieved in 100% of patients at just 6-8° and 4-6° for activL and control patients, respectively. CONCLUSIONS These data show that for patients with TDR at L5-S1, a greater proportion exhibited clinically significant improvements in lower back disability and pain when there was more motion at the index level at 5 years postsurgery, suggesting motion preservation has an impact on function and pain for L5-S1 index level procedures. ActivL improved L5-S1 ROM significantly better than ProDisc-L or Charite. FDA DEVICE/DRUG STATUS ActivL, Prodisc-L, and Charite: Approved for this indication.