Computed Three-Dimensional Atlas of Subthalamic Nucleus and Its Adjacent Structures for Deep Brain Stimulation in Parkinson's Disease

Background. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is one of the standard surgical treatments for advanced Parkinson's disease. However, it has been difficult to accurately localize the stimulated contact area of the electrode in the subthalamic nucleus and its adjacent structures using a two-dimensional atlas. The goal of this study is to verify the real and detailed localization of stimulated contact of the DBS electrode therapeutically inserted into the STN and its adjacent structures using a novel computed three-dimensional atlas built by a personal computer. Method. A three-dimensional atlas of the STN and its adjacent structures (3D-Subthalamus atlas) was elaborated on the basis of sagittal slices from the Schaltenbrand and Wahren stereotactic atlas on a personal computer utilizing a commercial software. The electrode inserted into the STN and its adjacent structures was superimposed on our 3D-Subthalamus atlas based on intraoperative third ventriculography in 11 cases. Findings. Accurate localization of the DBS electrode was identified using the 3D-Subthalamus atlas, and its clinical efficacy of the electrode stimulation was investigated in all 11 cases. Conclusion. This study demonstrates that the 3D-Subthalamus atlas is a useful tool for understanding the morphology of deep brain structures and for the precise anatomical position findings of the stimulated contact of a DBS electrode. The clinical analysis using the 3D atlas supports the contention that the stimulation of structures adjacent to the STN, particularly the zona incerta or the field of Forel H, is as effective as the stimulation of the STN itself for the treatment of advanced Parkinson's disease

Hemiparesis Caused by Cervical Spontaneous Spinal Epidural Hematoma: A Report of 3 Cases

We report three cases of spontaneous spinal epidural hematoma (SSEH) with hemiparesis. The first patient was a 73-year-old woman who presented with left hemiparesis, neck pain, and left shoulder pain. A cervical MRI scan revealed a left posterolateral epidural hematoma at the C3–C6 level. The condition of the patient improved after laminectomy and evacuation of the epidural hematoma. The second patient was a 62-year-old man who presented with right hemiparesis and neck pain. A cervical MRI scan revealed a right posterolateral dominant epidural hematoma at the C6-T1 level. The condition of the patient improved after laminectomy and evacuation of the epidural hematoma. The third patient was a 60-year-old woman who presented with left hemiparesis and neck pain. A cervical MRI scan revealed a left posterolateral epidural hematoma at the C2–C4 level. The condition of the patient improved with conservative treatment. The classical clinical presentation of SSEH is acute onset of severe irradiating back pain followed by progression to paralysis, whereas SSEH with hemiparesis is less common. Our cases suggest that acute cervical spinal epidural hematoma should be considered as a differential diagnosis in patients presenting with clinical symptoms of sudden neck pain and radicular pain with progression to hemiparesis

Neural Sources of Vagus Nerve Stimulation–Induced Slow Cortical Potentials

[Objectives] This study investigated neuronal sources of slow cortical potentials (SCPs) evoked during vagus nerve stimulation (VNS) in patients with epilepsy who underwent routine electroencephalography (EEG) after implantation of the device. [Materials and Methods] We analyzed routine clinical EEG from 24 patients. There were 5 to 26 trains of VNS during EEG. To extract SCPs from the EEG, a high-frequency filter of 0.2 Hz was applied. These EEG epochs were averaged and used for source analyses. The averaged waveforms for each patient and their grand average were subjected to multidipole analysis. Patients with at least 50% seizure frequency reduction were considered responders. Findings from EEG analysis dipole were compared with VNS responses. [Results] VNS-induced focal SCPs whose dipoles were estimated to be located in several cortical areas including the medial prefrontal cortex, postcentral gyrus, and insula, with a significantly higher frequency in patients with a good VNS response than in those with a poor response. [Conclusions] This study suggested that some VNS-induced SCPs originating from the so-called vagus afferent network are related to the suppression of epileptic seizures

Distorted depth perception under the microscope : compensation by surgical navigator and image projection

Object. Spatial perceptions by the naked eye and under the surgical microscope were compared between groups of experienced and inexperienced neurosurgeons to understand distortion in the three-dimensional recognition of the surgical field. Methods. A phantom surgical field containing a start point, arbitrarily set virtual gate, and a target point was fixed under a video-see-through microscope which allows projection of navigational image into microscopic view. The surgical navigator was used to record the spatial position of the suction tip. Examinees were first shown the position of the invisible virtual gate. Then they were asked to point consecutively to three points with the suction tip under four different visual conditions; by the naked eye, under the microscope, while watching a navigator monitor, and under the microscope with projection of navigational image. The pointing deviation from the suction tip to the virtual gate, the trajectory of suction tip and the operation time were evaluated. By the naked eye, pointing accuracy did not differ between the two groups. However, accuracy under the microscope was significantly worse in inexperienced group. Further analysis demonstrated that these differences were attributable to inaccurate depth perception. With the navigational image projection, the accuracy and the operation time were significantly improved in both groups. Conclusions. Under the microscope, the spatial perception was considerably distorted, especially in the depth component. Application of the navigator improved this perception considerably. The navigational image projection into the microscope further improved spatial perception and lead to better visuomotor coordination under the microscope