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Introduction: Deep brain stimulation (DBS) is an effective treatment for multiple movement disorders and shows substantial promise for the treatment of some neuropsychiatric and other disorders of brain neurocircuitry. Optimal neuroanatomical lead position is a critical determinant of clinical outcomes in DBS surgery. Lead migration, defined as an unintended post-operative displacement of the DBS lead, has been previously reported. Despite several reports, however, there have been no systematic investigations of this issue. This study aimed to: 1) quantify the incidence of lead migration in a large series of DBS patients, 2) identify potential risk factors contributing to DBS lead migration, and 3) investigate the practical importance of this complication by correlating its occurrence with clinical outcomes. Methods: A database of all DBS procedures performed at UF was queried for patients who had undergone multiple post-operative DBS lead localization imaging studies separated by at least two months. Bilateral DBS implantation has commonly been performed as a staged procedure at UF, with an interval of six or more months between sides. To localize the position of each DBS lead, a head CT is acquired ~4 weeks after lead implantation and fused to the pre-operative targeting MRI. The fused targeting images (MR + stereotactic CT) acquired in preparation for the delayed second side lead implantation provide an opportunity to repeat the localization of the first implanted lead. This paradigm offers an ideal patient population for the study of delayed DBS lead migration because it provides a large cohort of patients with localization of the same implanted DBS lead at two time points. The position of the tip of each implanted DBS lead was measured on both the initial post-operative lead localization CT and the delayed CT. Lead tip displacement, intracranial lead length, and ventricular indices were collected and analyzed. Clinical outcomes were characterized with validated rating scales for all cases, and a comparison was made between outcomes of cases with lead migration versus those where migration of the lead did not occur. Results: Data from 138 leads in 132 patients with initial and delayed lead localization CT scans were analyzed. The mean distance between initial and delayed DBS lead tip position was 2.2 mm and the mean change in intracranial lead length was 0.45 mm. Significant delayed migration (>3 mm) was observed in 17 leads in 16 patients (12.3% of leads, 12.1% of patients). Factors associated with lead migration were: technical error, repetitive dystonic head movement, and twiddler’s syndrome. Outcomes were worse in dystonia patients with lead migration (p = 0.035). In the PD group, worse clinical outcomes trended in cases with lead migration. Conclusions: Over 10% of DBS leads in this large single center cohort were displaced by greater than 3 mm on delayed measurement, adversely affecting outcomes. Multiple risk factors emerged, including technical error during implantation of the DBS pulse generator and failure of lead fixation at the burr hole site. We hypothesize that a change in surgical technique and a more effective lead fixation device might mitigate this problem. [ABSTRACT FROM AUTHOR]

Objective: Deep brain stimulation (DBS) has been used for more than a decade to treat Parkinson's disease (PD); however, its mechanism of action remains unknown. Given the close proximity of the electrode trajectory to areas of the brain known as the “germinal niches,” we sought to explore the possibility that DBS influences neural stem cell proliferation locally, as well as more distantly. Methods: We studied the brains of a total of 12 idiopathic Parkinson's disease patients that were treated with DBS (the electrode placement occurred 0.5–6 years before death), and who subsequently died of unrelated illnesses. These were compared to the brains of 10 control individuals without CNS disease, and those of 5 PD patients with no DBS. Results: Immunohistochemical analyses of the subventricular zone (SVZ) of the lateral ventricles, the third ventricle lining, and the tissue surrounding the DBS lead revealed significantly greater numbers of proliferating cells expressing markers of the cell cycle, plasticity, and neural precursor cells in PD-DBS tissue compared with both normal brain tissue and tissue from PD patients not treated with DBS. The level of cell proliferation in the SVZ in PD-DBS brains was 2–6 fold greater than that in normal and untreated PD brains. Conclusions: Our data suggest that DBS is capable of increasing cellular plasticity in the brain, and we hypothesize that it may have more widespread effects beyond the electrode location. It is unclear whether these effects of DBS have any symptomatic or other beneficial influences on PD. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: To compare subthalamic nucleus (STN) to globus pallidus internus (GPi) deep brain stimulation (DBS) for control of motor fluctuations and for potential dyskinesia-suppressing qualities. Methods: We conducted a retrospective database review of all patients who underwent GPi or STN DBS for idiopathic Parkinson''s disease. Direct dyskinesia suppression (dDS) was defined as improvement in dyskinesia subscore of the Unified Parkinson''s Disease Rating Scale (UPDRS) part IV (items 32–34), despite lack of reduction in dopaminergic medication dosage. We analyzed the data using methods appropriate for a case–control study. Results: A total of 133 patients were evaluated. At the last evaluation Dyskinesia scores and motor fluctuations significantly improved in both the GPi (p < 0.0001) and STN groups (p < 0.0001). The GPi group was more likely than the STN group to experience dDS (odds ratio = 1.95, 95% CI = 0.556, 3.21). However, the association between DBS target and dDS was not statistically significant (Pearson chi-square = 2.286, p = 0.131). Conclusions: The overall clinical outcome of STN and GPi DBS for control of dyskinesia and motor fluctuations was similar. STN and GPi DBS both had some direct dyskinesia suppression effects. [Copyright &y& Elsevier]