Hemorrhagic and repositioning risk factors related to intraoperative multitrack microrecording on a large series of patients treated for deep brain stimulation

Background: Deep brain stimulation (DBS) is a commonly performed surgical technique used to treat various movement disorders. Despite DBS being nonablative and minimally invasive, numerous complications and side effects have been recorded, the most critical of which are intracranial ischaemic/hemorrhagic events. Methods: We analyzed this complication in relation to simultaneous multitrack microrecording (MER) as observed in our experience. The possible contribution of MER to the precision of the DBS procedure was also evaluated. From October 1996 to January 2010, 532 consecutive procedures were performed at the Unit of Functional Neurosurgery, Division of Neurosurgery IRCCS Galeazzi in Milan, and at the Istituto Besta IRCCS in Milan by 2 of the Authors (D.S. and M.S.), on a total number of 272 patients. Findings: Ischaemic/hemorrhagic complications were documented in 9 patients (1.6%), and 5 of them presented with a neurological syndrome. Overall mortality was 3 patients (1.1%), and was correlated with intracranial hemorrhage in 1 patient. Repositioning of incorrectly positioned electrodes was deemed necessary in 26 procedures (4.9%) on 23 patients (8.4%). Conclusions: Although no consistent association was documented between the use of simultaneous intraoperative multitrack MER and hemorrhage, a statistically significant association was recorded between an incorrect positioning of the definitive leads, as reported in the postoperative magnetic resonance imaging controls or at the intraoperative computed tomographic (CT) scans, and the lack of intraoperative MER. DBS proves to be a safe and effective procedure even for novel indications. In our experience, no association was found between hemorrhagic risk and simultaneous multitrack MER

Subthalamic local field potentials after seven-year deep brain stimulation in Parkinson's disease

Studies describing subthalamic (STN) local field potentials (LFPs) recorded during deep brain stimulation (DBS) in patients with Parkinson's disease (PD), within the first month after DBS electrode implant, show that DBS modulates specific STN oscillations: whereas low-frequency (LF) oscillations (2-7 Hz) increase, beta oscillations (8-30 Hz) variably decrease. No data show whether LFPs remain stable for longer than one month after DBS surgery. Having long-term information is essential especially for use as a long-term feedback control signal for adaptive DBS systems. To evaluate how STN activity behaves years after prolonged chronic stimulation in PD we studied STN LFPs at rest without DBS and during ongoing DBS, in 11 parkinsonian patients 7 years (7.54\ub11.04) after STN electrode implantation for DBS (hyperchronic group) and in 16 patients 3 days after STN electrode implantation (acute group). STN LF and beta-band LFPs recorded at rest at 7 years contained almost the same information as those recorded at 3 days. STN recordings showed similar LFP responses to DBS in the acute and hyperchronic stages: whereas during ongoing DBS the LF power band increased for the whole population, beta activity decreased only in nuclei with significant beta activity at baseline. The LF/beta power ratio in all nuclei changed in both study groups, suggesting that this variable might be an even more informative marker of PD than the single LF and beta bands. Because STN LFP activity patterns and STN LFP responses to DBS stay almost unchanged for years after DBS electrode implantation they should provide a consistent feedback control signal for adaptive DBS

The Effects of Levodopa and Deep Brain Stimulation on Subthalamic Local Field Low-Frequency Oscillations in Parkinson's Disease

New adaptive systems for deep brain stimulation (DBS) could in the near future optimize stimulation settings online so as to achieve better control over the clinical fluctuations in Parkinson's disease (PD). Local field potentials (LFPs) recorded from the subthalamic nucleus (STN) in PD patients show that levodopa and DBS modulate STN oscillations. Because previous research has shown that levodopa and DBS variably influence beta LFP activity (8-20 Hz), we designed this study to find out how they affect low-frequency (LF) oscillations (2-7 Hz). STN LFPs were recorded in 19 patients with PD during DBS, after levodopa medication, and during DBS and levodopa intake combined. We investigated the relationship between LF modulations, DBS duration and levodopa intake. We also studied whether LF power depended on disease severity, the patient's clinical condition and whether LF modulations were related to electrode impedances. LF power increased during DBS, after levodopa intake and under both experimental conditions combined. The LF power increase correlated with the levodopa-induced clinical improvement and the higher the electrode impedance, the greater was the LF power change. These data suggest that the LF band could be useful as a control neurosignal for developing novel adaptive DBS systems for patients with PD

Cervical synovial cyst: case report and review of literature

Synovial cysts, typically observed in the lumbar spine eventually associated with degenerative changes of the facet joints, only rarely present in the cervical spine. Up to now, only 28 symptomatic cases are described in literature. Typically, the treatment of these cases is a decompressive laminectomy followed by complete surgical removal of the lesion. The authors present the case of an 84-year-old man with a symptomatic synovial cyst involving the space between C7 and T1