Total Joint Replacement of the Lumbar Spine: 12-Month Pain and Functional Outcomes From an Investigational Device Exemption Clinical Trial.

backgroundLumbar 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).

methodsThis 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

resultsBaseline 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;

conclusionsSubstantial 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.