Impact of Postoperative Chronic Back Pain Syndrome on the Incidence of Psychiatric and Brain Disorders, and All-Cause Mortality.

Purpose: Postoperative chronic back pain syndrome (PCBPS) is characterized by persistent or recurrent symptoms following lumbar spine surgery. This study aimed to investigate its long-term associations with psychiatric and brain disorders, and mortality outcomes. Patients and Methods: This retrospective cohort study utilized the Korean National Health Insurance Service database. Patients who underwent lumbar spinal surgery between 2009 and 2023 were included (n= 603,272). PCBPS was operationally defined using three criteria: diagnosis code for post-laminectomy syndrome (PCBPS-D group), prolonged gabapentinoid prescription (≥12 weeks) (PCBPS-G group), and reoperation (PCBPS-R group). Psychiatric disorders (anxiety, depression, and insomnia), brain disorders (stroke, Parkinson's disease, and dementia), and all-cause mortality were assessed as outcomes. Results: Among the cohort, 169,796 patients (28.1%) met at least one PCBPS definition. PCBPS was significantly associated with psychiatric disorders (aHR 1.15; 95% CI, 1.13-1.17), including anxiety (aHR 1.15; 95% CI, 1.11-1.19), depression (aHR 1.20; 95% CI, 1.15-1.24), and insomnia (aHR 1.14; 95% CI, 1.11-1.18). PCBPS was also linked to increased risk of brain disorders (aHR 1.09; 95% CI, 1.07-1.11), including stroke (aHR 1.15; 95% CI, 1.12-1.19), Parkinson's disease (aHR 1.40; 95% CI, 1.27-1.55), and dementia (aHR 1.07; 95% CI, 1.05-1.09). Moreover, PCBPS was associated with higher all-cause mortality (aHR 1.10; 95% CI, 1.07-1.12). These associations remained robust across PCBPS sub-definitions and stratified analyses. Conclusion: PCBPS is associated with increased risks of psychiatric disorders, brain diseases, and mortality. These findings emphasize the need for early identification and integrative management in patients with chronic postsurgical pain.