How Do Patient-Reported Outcomes Vary Between Lumbar Fusion Patients with Complete Versus Incomplete Follow-Up?

Abstract

We sought to assess differences in patient-reported outcome measures (PROMs) between patients who do and do not follow up for 2 years after lumbar fusion. Primary, elective, single-level anterior lumbar interbody fusion, lateral lumbar interbody fusion, or transforaminal lumbar interbody fusion procedures were identified. Patients were grouped by 2-year PROM follow-up completion. Mean and delta PROM scores for visual analog scale (VAS) back and leg, Oswestry Disability Index (ODI), short-form (SF)-12 Physical Composite Score (PCS), and Mental Composite Score (MCS) were computed for both groups preoperatively and postoperatively. Minimum clinically important difference (MCID) achievement was determined for PROM scores using established threshold values. Linear and logistic regression assessed mean and ΔPROM scores as predictors of 2-year follow-up completion and compared MCID achievement between groups, respectively. We included 316 lumbar fusion patients. PROM scores were more favorable for complete follow-up patients for 6-month VAS back (P= 0.003), 6-month and 1-year ODI (P ≤ 0.027, both), and 6-week and 6-month SF-12 PCS (P ≤ 0.015, both). Six-month VAS back (P= 0.007); 6-month and 1-year ODI (P ≤ 0.028, both); 6-week, 6-month, and 1-year SF-12 PCS (P ≤ 0.041, all); and 6-week SF-12 MCS (P ≤ 0.028, both) significantly predicted 2-year follow-up. ΔPROMs significantly differed between groups at 1 year for ΔVAS leg (P= 0.029), ΔODI (P= 0.013), and ΔSF-12 MCS (P= 0.004). One-year ΔVAS leg (P= 0.035), ΔODI (P= 0.011), and ΔSF-12 MCS (P= 0.003) significantly predicted follow-up. MCID achievement for ΔPROMs significantly differed between groups for 6-week VAS leg (P= 0.035), overall ODI (P= 0.034), and SF-12 PCS from 12 weeks through 1 year (P ≤ 0.011, all) and overall (P < 0.001). Patients with full follow-up demonstrated significantly more favorable outcome scores and improvement in pain, disability, and physical function at several postoperative time points.