Related Experiment Video
Updated: Jan 14, 2026
Three-dimensional Navigation-guided, Prone, Single-position, Lateral Lumbar Interbody Fusion Technique
Published on: July 15, 2021
Total Joint Replacement of the Lumbar Spine: 12-Month Pain and Functional Outcomes From an Investigational Device
Pierce D Nunley1, J Alex Sielatycki2, S Craig Humphreys3
1Spine Institute of Louisiana, Shreveport, LA, USA.
Background:
Lumbar fusion eliminates motion at the operative level and is associated with altered load transfer and adjacent segment degeneration. Total joint replacement (TJR) of the lumbar spine is a motion segment reconstruction procedure performed via a bilateral transforaminal approach that allows direct neural decompression and replacement of both disc and facet function. This prospective investigational device exemption clinical trial compared TJR with a concurrent, propensity-score-weighted real-world evidence cohort treated with either instrumented transforaminal lumbar interbody fusion (TLIF) or posterior lumbar interbody spine fusion (PLIF).
Methods:
This multicenter investigational device exemption trial was conducted at 20 US sites. Patient-reported outcomes from 152 TJR subjects implanted with the MOTUS device were compared with 142 propensity score-weighted TLIF/PLIF controls. Lumbar-related disability was measured with the Oswestry Disability Index (ODI) and back and worst leg pain severity by a 100-mm visual analog scale (VAS). Minimal clinically important difference thresholds were ODI ≥ 15 points and VAS ≥ 20 mm; responder analyses were also conducted using ≥30% and substantial clinical benefit (≥50%) thresholds. Effect sizes were calculated using Cohen's d or h.
Results:
Baseline characteristics were well balanced, and there were no statistically significant differences between study groups. At 12 months, mean ODI decreased by 45 points (71%) with TJR and 37 points (59%) with TLIF/PLIF. The adjusted between-group difference was 8.1 points (95% CI, 2.5-13.7; P = 0.005; Cohen's d = 0.39, small). VAS back and leg pain decreases were similar between groups, with no significant between-group differences. Minimal clinically important difference responder rates were high (>85%) for both procedures; the ≥30% ODI threshold favored TJR (90% vs 80%; P = 0.04).
Conclusions:
Substantial decreases in back impairment and pain severity were realized in both study groups. However, longitudinal improvement in ODI significantly favored patients treated with TJR.
Clinical Relevance:
Lumbar TJR combines decompression with motion preservation in a single procedure, potentially offering an alternative to fusion in selected patients. The advantage of utilizing a standard posterior operative approach with TJR is that it allows for direct decompression of the neural elements prior to implant placement.
Level Of Evidence:
2b.
