Are Preoperative Health-Related Quality of Life Scores Predictive of Clinical Outcomes After Lumbar Fusion?

Study Design. Prospective longitudinal cohort. Objective. This study evaluated the effect of preoperative Mental Component Summary (MCS), preoperative Physical Component Summary (PCS), preoperative Oswestry Disability Index (ODI), back pain predominance, body mass index (BMI), age, smoking status, and workers' compensation on health-related quality of life after lumbar fusion. These factors were selected as they are readily available and may influence a surgeon's decision-making process. Summary of Background Data. Measures of health-related quality of life are increasingly used to evaluate treatment effectiveness. However, their use as a predictive tool to determine which patients will improve has been limited. Methods. The Short Form 36 (SF-36) and ODI were collected before surgery and two years after surgery in 489 patients undergoing lumbar fusion for degenerative disorders. Linear regression modeling was used to determine the effect of preoperative MCS, preoperative PCS, preoperative ODI, back pain predominance, BMI, age, smoking status, and workers' compensation on the change in ODI and change in SF-36 PCS two years after lumbar fusion. Results. Patients with better preoperative MCS (P = 0.008) and worse preoperative ODI scores (P < 0.0001) achieved greater ODI improvement. Workers' compensation patients did significantly worse (P = 0.03). Patients with better preoperative MCS (P = 0.0004), better preoperative PCS (P = 0.0155), and worse preoperative ODI scores (P = 0.0210) achieved greater PCS improvement. Those on workers' compensation had lower changes in PCS, an effect that was nearly significant (P = 0.0644). There were no significant correlations between PCS and ODI improvement and back pain predominance, BMI, age, and smoking status. Attempts at determining threshold values for MCS, PCS, and ODI that are predictive of a patient achieving minimum clinically important difference for PCS and ODI wereunsuccessful. Conclusion. Patients with good preoperative MCS and poor preoperative ODI scores who are not on workers' compensation are more likely to improve after lumbar fusion. Threshold values for MCS, PCS, and ODI predictive of a patient achieving minimum clinically important difference for PCS and ODI could not be determined.