Postoperative Confusion in Patients with Parkinson Disease Undergoing Deep Brain Stimulation of the Subthalamic Nucleus

BACKGROUND: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an established treatment for patients with Parkinson disease. One adverse event is the development of postoperative confusion. The aim of this study was to report the incidence and associated factors of postoperative confusion after STN DBS surgery. METHODS: This was a retrospective cohort study by chart review of patients with Parkinson disease who underwent STN DBS in a Brazilian public academic hospital from January 2013 to October 2017. The primary outcome was the incidence of postoperative confusion. The association of the outcome and imaging and clinical variables was evaluated. RESULTS: Among 49 patients who underwent STN DBS for Parkinson disease, the incidence of postoperative confusion was 26.5% (95% confidence interval 15%-41.1%). Univariate analysis identified the following variables associated with development of confusion: age (63.2 +/- 7.8 years vs. 55.4 +/- 9.1 years, P = 0.009), disease duration (16.5 +/- 5.1 years vs. 13.2 +/- 4.2 years, P = 0.027), Charlson comorbidity index (2 [interquartile range 1-3] vs. 1 [0-1 interquartile range], P = 0.002), width of the third ventricle (5.4 +/- 2.1 mm vs. 4 +/- 1.6 mm, P = 0.018), and cella media index (5 +/- 1 vs. 5.6 +/- 0.8, P = 0.018). After adjustment, Charlson comorbidity index remained significant (adjusted relative risk 1.64, 95% confidence interval 1.17-2.3, P = 0.004). CONCLUSIONS: The incidence of postoperative confusion in this cohort was 26.5%. After analysis of confounding factors, the Charlson comorbidity index was significantly associated with postoperative confusion.