When the Data Favor Motion Preservation, How Long Does It Take for Surgeon Culture to Catch Up?

Key Takeaways

• TOPS achieved 85% composite clinical success versus 64% TLIF.
• 93% of TOPS patients improved ODI ≥15 points, versus 81% TLIF.
• L4‑5 range of motion unchanged at 2‑year follow‑up.
• Reoperation rate lower with TOPS (5.9%) than TLIF (8.8%).
• Facet arthroplasty offers motion preservation without higher complications.

Pulse Analysis

For decades, lumbar fusion—especially TLIF—has been the default for grade I degenerative spondylolisthesis, despite concerns about adjacent‑segment disease and loss of spinal flexibility. Surgeons have relied on pedicle‑screw constructs to achieve stability, but the trade‑off is permanent arthrodesis, which can limit motion and potentially accelerate wear at neighboring levels. As the population ages and demand for functional preservation grows, the spine community has been eager for evidence‑based alternatives that maintain mobility while providing comparable stability.

The FDA‑approved IDE trial of the Total Posterior Spine (TOPS) system enrolled 249 patients across 37 sites, randomizing 170 to the facet‑replacement device and 79 to TLIF. At a minimum 24‑month follow‑up, TOPS outperformed fusion on the composite success metric (85% vs 64%) and on the Oswestry Disability Index, where 93% of TOPS recipients achieved a ≥15‑point improvement versus 81% with TLIF. Pain scores improved similarly in both arms, indicating effective decompression, while reoperations were modestly lower for TOPS (5.9% vs 8.8%). Most strikingly, the segment’s range of motion remained essentially unchanged (3.85° pre‑op to 3.86° at two years), confirming the device’s motion‑preserving claim.

These findings could accelerate a cultural shift among spine surgeons who have long equated instability with fusion. By delivering functional benefits without added risk, TOPS positions itself as a viable competitor for a subset of patients—those with mobile, grade I slips and significant stenosis. Market analysts may see increased adoption as reimbursement pathways solidify and long‑term data accumulate. However, widespread acceptance will depend on surgeon training, device cost considerations, and real‑world durability beyond the trial’s two‑year horizon. If those hurdles are cleared, motion preservation could become a new standard alongside traditional fusion techniques.