This study examines the associations between preoperative Patient-Reported Outcomes Measurement Information System (PROMIS) physical function (PF) score, measured by PROMIS-PF and the change between pre- and postoperative PROMIS-PF scores.
A prospectively maintained surgical registry was retrospectively reviewed for spine surgeries between May 2015-June 2019. Inclusion criteria were primary, single-level minimally invasive transforaminal lumbar interbody fusions. Revisions, multilevel procedures, and patients missing preoperative surveys were excluded. Patients were grouped by preoperative PROMIS-PF scores of ≥ 35 and < 35, with higher scores indicating greater PF. A chi-squared and Student t-test were used to analyze categorical and continuous variables respectively. Linear regression evaluated the relationship of PROMIS-PF score improvement.
Of the 180 subjects, 84 were in the PROMIS-PF < 35 group which had more obese patients (p < 0.001) and more males (p = 0.001). Length of stay was greater for the PROMIS-PF < 35 group (36.2 hours vs. 28.7 hours, p = 0.014). PROMIS-PF and Oswestry Disability Index scores were significantly different between subgroups at all timepoints. PROMIS-PF < 35 cohort had larger postoperative PROMIS-PF improvements at 6 weeks (p = 0.008) and 12 weeks (p = 0.003). Linear regression demonstrated a negative association between preoperative PROMIS-PF scores and improvement at 6 weeks, 12 weeks, 6 months, and 2 years (p < 0.001). PROMIS-PF < 35 demonstrated significantly lower rate of achieving minimum clinically important difference at 6 months, otherwise no difference observed throughout the 2-year follow-up.
Up to 6 months postoperatively, lower preoperative PROMIS-PF scores were associated with larger PROMIS-PF improvements. Understanding the relationship preoperative PROMIS-PF scores have with postoperative improvement may enable better patient counseling.
Minimally invasive transforaminal lumbar interbody fusion; Oswestry Disability Index; Patient-Reported Outcomes Measurement Information System; Physical function; Visual analogue scale.