Validity of PROMIS in minimally invasive transforaminal lumbar interbody fusion: a preliminary evaluation

OBJECTIVE Patient-reported outcomes are commonly used to evaluate treatment efficacy. Inefficiencies in standard measurement tools often prove to be a barrier to data collection. The Patient-Reported Outcomes Measurement Information System (PROMIS) was developed to overcome these limitations. This tool implements computer-adaptive testing, which enables the assessment of physical function in fewer questions than those required for "static" metrics. In spine surgery patients, moderate to strong correlations with Oswestry Disability Index (ODI) and the 36-Item Short Form Survey (SF-36) scores have been reported for PROMIS. However, to date, data regarding the efficacy of this tool for patients undergoing minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF) have been limited. METHODS A prospectively maintained registry of patients who have undergone primary 1- or 2-level MIS TLIF was reviewed retrospectively. Patients with incomplete PROMIS data were excluded. Changes in PROMIS physical function scores 6 weeks, 12 weeks, and 6 months after surgery were analyzed using paired t-tests. PROMIS scores were compared with traditional outcome measures, including SF-12 physical function, ODI, and visual analog scale (VAS) back and leg scores. Correlations were tested using the Pearson correlation coefficient, and the strength of association was interpreted as follows: small, 0.1 ≤ |r| < 0.3; moderate, 0.3 ≤ |r| < 0.5; and large, |r| ≥ 0.5. Statistical significance was set at p < 0.05. RESULTS Seventy-four patients were included in this analysis after the exclusion of those without PROMIS scores. The mean preoperative PROMIS score was 35.92 ± 6.98. Significant improvements were demonstrated in PROMIS scores 12 weeks (41.33, p < 0.001) and 6 months (43.58, p < 0.001) after surgery. PROMIS scores demonstrated a significant correlation with SF-12, ODI, and VAS leg scores (p < 0.05). Strong associations with PROMIS scores were observed for SF-12 (r = 0.650 to 0.854), ODI (r = -0.525 to -0.831), and 6-month VAS back (r = -0.693) scores. CONCLUSIONS Physical function as measured by PROMIS improves significantly 12 weeks and 6 months after MIS TLIF. In addition, PROMIS scores have strong correlations with SF-12 and ODI scores. These results suggest that PROMIS scores can be used as a valid assessment of physical function in MIS TLIF patients. Further work is required to determine the full benefits of this measure in other spine populations.