Impact of preoperative depression on 2-year clinical outcomes following adult spinal deformity surgery: The importance of risk stratification based on type of psychological distress

OBJECTIVE: The objective of this study was to isolate whether the effect of a baseline clinical history of depression on outcome is independent of associated physical disability and to evaluate which mental health screening tool has the most utility in determining 2-year clinical outcomes after adult spinal deformity (ASD) surgery. METHODS: Consecutively enrolled patients with ASD in a prospective, multicenter ASD database who underwent surgical intervention with a minimum 2-year follow-up were retrospectively reviewed. A subset of patients who completed the Distress and Risk Assessment Method (DRAM) was also analyzed. The effects of categorical baseline depression and DRAM classification on the Oswestry Disability Index (ODI), SF-36, and Scoliosis Research Society questionnaire (SRS-22r) were assessed using univariate and multivariate linear regression analyses. The probability of achieving ≥ 1 minimal clinically important difference (MCID) on the ODI based on the DRAM's Modified Somatic Perceptions Questionnaire (MSPQ) score was estimated. RESULTS: Of 267 patients, 66 (24.7%) had self-reported preoperative depression. Patients with baseline depression had significantly more preoperative back pain, greater BMI and Charlson Comorbidity Indices, higher ODIs, and lower SRS-22r and SF-36 Physical/Mental Component Summary (PCS/MCS) scores compared with those without self-reported baseline depression. They also had more severe regional and global sagittal malalignment. After adjusting for these differences, preoperative depression did not impact 2-year ODI, PCS/MCS, or SRS-22r totals (p > 0.05). Compared with those in the "normal" DRAM category, "distressed somatics" (n = 11) had higher ODI (+23.5 points), lower PCS (-10.9), SRS-22r activity (-0.9), and SRS-22r total (-0.8) scores (p ≤ 0.01), while "distressed depressives" (n = 25) had lower PCS (-8.4) and SRS-22r total (-0.5) scores (p < 0.05). After adjusting for important covariates, each additional point on the baseline MSPQ was associated with a 0.8-point increase in 2-year ODI (p = 0.03). The probability of improving by at least 1 MCID in 2-year ODI ranged from 77% to 21% for MSPQ scores 0-20, respectively. CONCLUSIONS: A baseline clinical history of depression does not correlate with worse 2-year outcomes after ASD surgery after adjusting for baseline differences in comorbidities, health-related quality of life, and spinal deformity severity. Conversely, DRAM improved risk stratification of patient subgroups predisposed to achieving suboptimal surgical outcomes. The DRAM's MSPQ was more predictive than MCS and SRS mental domain for 2-year outcomes and may be a valuable tool for surgical screening.