Study design: Retrospective.
Objective: The aim of this study was to evaluate the validity of Patient Health Questionnaire-9 (PHQ-9) among patients undergoing minimally invasive (MIS) lumbar interbody fusion.
Summary of background data: Few studies have evaluated the utility and concurrent validity of the PHQ-9 survey in patients undergoing spinal procedures.
Methods: Patients undergoing a one- or two-level MIS lumbar interbody fusion were retrospectively reviewed. Patient-reported outcome surveys were completed preoperatively and at 6-week, 12-week, 6-month, and 1-year timepoints. Postoperative survey scores were compared to preoperative values using paired t tests. PHQ-9 scores were compared with the Mental Component Summary (MCS) scores of the Short Form-12 (SF-12) and the Veterans RAND-12 (VR-12) surveys at each timepoint using the Pearson correlation coefficient.
Results: A total of 215 patients were included in the analysis. The mean preoperative scores for the PHQ-9, SF-12 MCS, and VR-12 MCS were 6.78, 49.55, and 50.39, respectively. Significant improvements in each survey outcome measure were observed at all postoperative timepoints. Strong correlations with PHQ-9 scores were identified for SF-12 MCS scores and VR-12 MCS scores at preoperative and postoperative timepoints (|r| ≥ 0.5 and P < 0.05 for each).
Conclusion: This study demonstrated that mental health, as measured by the PHQ-9, SF-12 MCS, and VR-12 MCS surveys, improves significantly after MIS lumbar fusion. In addition, PHQ-9 scores were strongly correlated with SF-12 and VR-12 scores. These results suggest that PHQ-9 can be a valid assessment of baseline mental health and postoperative improvement after MIS lumbar fusion. Concordant results among PHQ-9, SF-12 MCS, and VR-12 indicate that the simultaneous utilization of multiple survey instruments may not be necessary. Limiting the number of questionnaires that are administered in the evaluation of mental health could also help reduce survey burden placed on patients.
Level of evidence: 3.