Are Preoperative PHQ-9 Scores Predictive of Postoperative Outcomes Following Anterior Cervical Discectomy and Fusion?

STUDY DESIGN: This is a retrospective study. OBJECTIVE: The objective of this study was to determine if there is an association between preoperative depression, as quantified by Patient Health Questionnaire-9 (PHQ-9), and postoperative improvement in pain and disability after anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: Few studies have quantified depression symptoms in the preoperative period using PHQ-9 and have tracked patient-reported outcomes (PROs) following ACDF. METHODS: Patients undergoing ACDF were retrospectively reviewed and stratified by their preoperative PHQ-9 score. PROs, including Neck Disability Index (NDI), Visual Analogue Scale (VAS) neck and arm pain, and 12-Item Short Form (SF-12) Physical Component Score (PCS), were measured preoperatively and at 6-week, 3-month, 6-month, and 1-year postoperatively. PRO scores were analyzed amongst PHQ-9 cohorts using multiple linear regression. Achievement of minimum clinically important difference (MCID) was compared using chi analysis. RESULTS: Higher PHQ-9 scores were associated with increased preoperative NDI, VAS neck, and VAS arm scores and significantly lower SF-12 PCS scores preoperatively. Cohorts experienced similar VAS pain scores up to 1-year following surgery, except for VAS neck pain at 3 months when patients with greater depression symptoms had more pain. High PHQ-9 patients had higher NDI values at 6 weeks and 3-month marks but had similar NDI scores at 6 months and 1-year. Similarly, SF-12 PCS scores were lower for patients with a higher PHQ-9 score at 3 and 6 months, however, both groups had similar scores at 1-year follow-up. A greater percentage of the high PHQ-9 cohort achieved MCID for NDI, however, there were no differences in MCID achievement for VAS neck, VAS arm, or SF-12 PCS. CONCLUSIONS: Patients with worse preoperative mental health reported significantly greater preoperative disability and pain. However, both cohorts demonstrated similar clinical recovery at the 1-year follow-up. These findings suggest patients with worse preoperative mental health can expect significant improvements in PROs following surgery.