Perilead Edema in Deep Brain Stimulation: Long-Term Outcomes and Etiologic Correlates

Objectives: Deep brain stimulation (DBS) is an effective surgical procedure for the treatment of Parkinson disease (PD) and other movement disorders. Immediate and delayed complications after DBS surgery have been described. Perilead edema (PLE) is a DBS-related complication for which the etiology remains unknown. Moreover, PLE frequency and long-term effects are subjects of ongoing debate. Our study aims to elucidate the long-term clinical and neuropsychologic effects of PLE and to find possible etiologic correlates. Materials and methods: We retrospectively collected clinical and neuropsychologic data from 51 patients with PD before and 1 year after DBS. PLE visualized on fluid attenuated inversion recovery magnetic resonance imaging (MRI) sequence was manually segmented. Using appropriate statistical tests, continuous and categorical variables were compared in patients with and those without PLE. A multivariate regression model was used to analyze the contribution of clinical variables to edema volume changes. Results: Overall, 68.62% of patients presented with PLE at the immediate postoperative MRI. Patients with PLE were significantly older (p < 0.001) and had more frequent postoperative confusion episodes (p = 0.025). Furthermore, more microelectrode recording (MER) tracks (p < 0.001) were used in patients with PLE. Multiple MER tracks were directly correlated with edema volume and were the only significant predictors of edema volume changes in a multivariate regression model. No differences were found in other clinical and neuropsychologic variables. Conclusions: PLE is a frequent postsurgical event and may cause transient postoperative confusion. It seems linked to older age and multiple MER tracks. Although it does not influence global motor and neuropsychologic outcomes, PLE contributes to postoperative confusion episodes. To avoid PLE sequelae, using multiple MER tracks in older patients should be discouraged.