Methods
pain, Oswestry Disability
ADVERSE EVENT, EVENT
As previously published and described in the 12-month interim analysis by Wind et al. [Dynamic x-rays (flexion/extension) were obtained at 3 months, 6 months, 12 months, and 24 months postoperatively, while computerized tomography (CT) scans were obtained at 12 and 24 months. Radiographic fusion at 24 months was assessed by an independent reviewer (TELOS Partners, Warsaw, IN, and MMI, Houston TX), with successful fusion being defined as: (1) lack of angular and translational motion (< 3° and < 3 mm, respectively) on Quantitative Motion Analysis (QMA) and (2) the presence of bridging bone across the adjacent endplates, or transverse processes on thin-cut CT scans. Both fusion criteria had to be met for the subject to be considered a fusion success. In multi-level procedures, all treated levels had to be fused to be considered a fusion success. Clinical outcomes included the Oswestry Disability Index (ODI), and Visual Analog Scales (VAS) for back and leg pain. Clinical outcomes were obtained preoperatively and 6 weeks, 3 months, 6 months, 12 months, and 24 months postoperatively. Adverse events were recorded from surgery through 24 months for each subject, including the event’s relatedness, severity, and outcome.Subject data was analyzed with SAS Version 9.4 (SAS Institute, Cary, NC). Counts and percentages were reported for categorical baseline variables; the mean standard deviation (SD) and range were reported for continuous variables. Preoperative and postoperative subject reported outcomes were compared with a Wilcoxon signed rank test. Correlation of outcomes to risk factors were calculated by chi-square test. Alpha was set at 0.05 and a p-value of ≤ 0.05 was considered significant.