Duration of Surgery and Intraoperative Blood Pressure Management Are Modifiable Risk Factors for Postoperative Neurocognitive Disorders After Spine Surgery

Abstract

Study Design. Prospective quasi-experimental observational study. Objective. The objective of this study was to evaluate whether duration of surgery is a modifiable risk factor for postoperative delirium (POD) after spine surgery and explore further modifiable risk factors. In addition, we sought to investigate the association between POD and postoperative cognitive dysfunction and persistent neurocognitive disorders. Summary of Background Data. Advances in spine surgery enable technically safe interventions in elderly patients with disabling spine disease. The occurrence of POD and delayed neurocognitive complications (e.g. postoperative cognitive dysfunction/persistent neurocognitive disorder) remain a concern since these contribute to inferior functional outcomes and long-term care dependency after spine surgery. Materials and Methods. This prospective single-center study recruited patients aged 60 years or above and scheduled for elective spine surgery between February 2018 and March 2020. Functional (Barthel Index, BI) and cognitive outcomes [Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) test battery; telephone Montréal Cognitive Assessment] were assessed at baseline, three (V3), and 12 months postoperatively. The primary hypothesis was that the duration of surgery predicts POD. Multivariable predictive models of POD included surgical and anesthesiological parameters. Results. Twenty-two percent of patients developed POD (n=22/99). In a multivariable model, duration of surgery [ORadj=1.61/h (95% CI, 1.20–2.30)], age [ORadj=1.22/yr (95% CI, 1.10–1.36)], and baseline deviations of intraoperative systolic blood pressure [25th percentile: ORadj=0.94/mm Hg (95% CI, 0.89–0.99); 90th percentile: ORadj=1.07/mm Hg (95% CI, 1.01–1.14)] were significantly associated with POD. Postoperative cognitive scores generally improved (V3, ΔCERAD total z-score: 0.22±0.63). However, this positive group effect was counteracted by POD [beta: −0.87 (95% CI, −1.31 to 0.42)], older age [beta: −0.03/yr (95% CI, −0.05 to 0.01)], and lack of functional improvement [ΔBI; beta: −0.04/point (95% CI, −0.06 to 0.02)]. Cognitive scores at twelve months remained inferior in the POD group, adjusted for baseline cognition/age. Conclusions. This study identified distinct neurocognitive effects after spine surgery, which are influenced by perioperative risk factors. Potential cognitive benefits are counteracted by POD, rendering its prevention critical in an aging population.