Indications and Contraindications

The selection criteria for insertion of the NCP system remain in evolution and reflect current governmental standards, as well as institutional biases and general guidelines from prior clinical trials 1,2 . Currently, the device is only approved by the FDA as an adjunctive therapy in reducing the frequency of seizures in adults and adolescents over 12 years of age with partial onset seizures which are refractory to antiepileptic medications'' 1 . However, favorable results have been obtained...

Macrostimulation

We recommend confirming the location of the target with macrostimulation using the standard stimulator (Neuro50, F. L. Fischer Leibinger, Freiburg, Germany), given the fact that the mere introduction of the needle generates microsignals that can be somewhat confusing. The setup parameters of the stimulator are square waves of 2 to 100 Hz, 1 to 10 mV, 1 ms of duration. Once the accuracy of the target has been confirmed, we proceed with permanent lesioning. In the case of deep brain stimulation,...

Technical Considerations

Spinal cord stimulation technology has evolved from the relatively simple monopolar electrodes used in the original studies during the mid-1960s 8,9 to sophisticated multielectrode arrays for monopolar, bipolar, and tripolar stimulation that may be attached either to a completely implantable system for impulse generation or to a radiofrequency-coupled system with an im-plantable receiver and externally attached antenna controlled by a battery-powered impulse generator (Table 2). The...

Foreword

This is an exciting time to be in stereotactic surgery. In a little more than 50 years, it has developed from a concept used in the animal laboratory to a technique that promises to permeate all of neurosurgery. Before human stereotactic surgery was born, functional neurosurgery consisted of a few adventurous procedures confined to interrupting pathways that were conveniently located superficially and were not overlain by other eloquent tracts. The only functional operations that were generally...

Longterm Results

Spinal cord DREZ lesioning has been used to successfully treat a number of neuropathic pain syndromes refractory to conventional treatment, including deafferentation syndromes, brachial and lumbar plexus avulsions, and pain secondary to spinal cord injury. In addition, nucleus caudalis DREZ lesioning has been successful in treating facial pain. Several clinical series demonstrate the utility of DREZ lesioning in the treatment of many intractable neuropathic pain syndromes and illustrate some of...

Introduction

Over the past decade, image-guided surgery has become one of the most exciting new technologies for the neurosurgeon. Advances in techniques and instrumentation have been rapid 1-9 . The Mayfield ACCISS image-guided stereotactic workstation OMI system has been developed to meet the image-guided needs of the most demanding surgeons Fig. 1 . With the May-field ACCISS, the surgeon can perform stereotactic-guided craniotomies, transphenoidal and other ears, nose, throat ENT skull-base procedures....

Neurological Disease And Therapy

Professor of Neurology Harvard University School of Medicine Beth Israel Deaconess Medical Center Boston, Massachusetts National Parkinson Foundation Miami, Florida Friedman Professor of Neurology Co-Director, Alzheimer's Disease Research Center Washington University School of Medicine St Louis, Missouri Professor of Neurology University of Missouri School of Medicine Chief of Neurology Children's Mercy Hospital Kansas City, Missouri Professor of Neurology Director, Movement Disorders Program...

References

Alexander III EB, Black PM, Wen PY, Fine H, Loeffler JS. Results of radiosurgery versus brachytherapy for malignant gliomas. In AAF De Salles and SJ Goetch eds . Stereotactic Surgery and Radiosurgery. Madison, Wisconsin Medical Physics Press, 1993, pp 455-461. 2. Betti OO, Munari C, Rosler R. Stereotactic radiosurgery with the linear accelerator Treatment of arteriovenous malformations. Neurosurgery 24 311-321, 1989. 3. Bortfeld T, Burkelbach J, Boesecke R, Schlegel W. Methods of image...

Stereotactic Imaging And Localization

Imaging is one of the most important aspects in radiosurgery. The accuracy achieved with stereotactic head rings and the Linac Scalpel treatment delivery system leaves the imaging modality used as the only uncertainty. Poor imaging techniques increase this uncertainty and nullify efforts to improve accuracy in treatment planning and delivery. Therefore, it is important to understand stereotactic imaging techniques, the increased quality assurance demands that are placed on the diagnostic...

Lars Leksell

It is well to reflect on the seminal contributions of Lars Leksell as we embrace new technology as a matter of course in the 21st century. A flurry of recent articles has appeared, for example, on the use of radiosurgery in trigeminal neuralgia. Few contemporary clinicians are aware that Leksell, in fact, pioneered this procedure in 1951, obtaining good results. He was also the first to perform intracavitary treatment of cystic craniopharyngiomas with phosphorus-32 1 . Leksell is best known...

System Setup

Voyager is composed of the dual CCD camera stand, the equipment rack with integrated flat panel light-emitting diode LED display and an optional outboard flat panel liquid crystal display LCD 7 . The camera stand houses a dual CCD infrared camera Northern Digital Inc. along with infrared emitters that allow for use of passive tools. The cameras may be oriented either horizontally or vertically, the latter allowing for a narrower line-of-sight corridor between the pointing devices and camera....

Ncp Device Components

Figure 1 depicts a schematic representation of VNS therapy. A pulse generator inserted in the subcutaneous tissues of the upper left side of the chest delivers intermittent electrical stimulation to the cervical vagus nerve trunk through a bifurcated helical lead. In addition to the implantable lead and pulse generator, the NCP system includes a number of peripheral components, such as a telemetry wand that interrogates and programs the pulse generator noninvasively. This programming wand is...

Target Localization Anatomical

Target selection depends on the surgeon's preferred surgical method and chosen treatment option. The target site is always contralateral to the predominant symptoms 1 . There are three possible targets for Parkinson's disease, depending on the predominant symptomatology the motor thalamus, Gpi, and STN 2 . All these structures may be localized indirectly by measuring fixed distances from well-known anatomical structures, such as the internal capsule, third ventricle, the optic tract, or the...

Surgical Technique

Anterior Temporal Horn

Preoperative treatment is similar to many craniotomies. Preoperative labs are limited to a complete blood count and AED levels, unless age or other medical conditions indicate additional tests. Patients are instructed to take nothing by mouth after midnight and to take any morning AEDs when they awaken. Patients are admitted to the hospital on the day of surgery. They are given a dose of prophylactic antibiotics in the preoperative holding area. All efforts are made to maintain therapeutic AED...

Target Localization for Stereotactic Biopsy

Imaging modality should depend on the modality that best demonstrates the lesion either CT, MRI, or angiography. Basic principles that should be applied when planning a trajectory to target. The instrument's trajectory should avoid eloquent brain and breach only one pial surface to minimize the change of hemorrhage. This is particularly true for lesions near the sylvian fissure or pineal region. When possible, the instrument should penetrate the brain parallel to white matter tracts, especially...

Technical Considerations in Movement Disorders Surgery

University of California San Francisco, San Francisco, California, U.S.A The major subcortical structures targeted for deep brain stimulation DBS or lesioning for the treatment of movement disorders include the nucleus ventralis intermedius Vim of the thalamus, the globus pallidus internal segment GPi , and the subthalamic nucleus STN . The major technical goal during surgery for movement disorders is to maximize both precision and safety. The methods for localization of the Vim, GPi, and STN...

Indications For Thalamic Surgery

Thalamotomy Mri

The indications for thalamotomy or thalamic stimulation are similar. Patients should have tremor that is refractory to medical therapy and represents the predominant form of disability. The best candidates for thalamic surgery are patients with incapacitating benign essential tremor and those with tremor-predominant PD that is unilateral or asymmetric. Patients with PD who have other motor signs should be considered for surgery aimed at other targets, such as the globus pallidus internus Gpi or...

Microelectrode Recording And Microstimulation

Microelectrode Recording Globus Pallidum

3.1 Overview of Microelectrode Recording Since its introduction by Albe-Fessard and Guiot 22 in the early 1960s, microelectrode recording MER has been performed in the human thalamus during surgery for parkinsonism and other movement disorders 23-33 . There is now a growing literature on microelectrode recording in the human GPi 34-41 and the human STN 42 . The most common technique is recording of single-unit, extracellular action potentials using high impedence 0.1-1.0 Mohm at 1000 Hz...

Impedance Monitoring And Stimulation Through A Macroelectrode

Additional intraoperative physiologic confirmation of the brain target may be obtained using the lesioning probe or deep brain stimulator. These macroelectrodes are typically about 1 mm in diameter and thus much too large to record cellular activity, but they can be used for impedance monitoring or electrical stimulation. Because the macroelectrode has a low impedance, the impedance of the surrounding brain tissue contributes significantly to current flow in response to applied voltage. Gray...

The Leksell Frame

After an inspiring visit with Spiegel and Wycis in Philadelphia, Leksell developed his first stereotactic frame 5 . His design included an arc system that was attached to a patient's head with pins such that the center of the arc corresponded to the selected target. The radius of the arc in the Leksell system is 190 mm, and stereotactic space is designated in a Cartesian coordinate system with center established, in millimeters, at x 100, y 100, and z 100 and zero, by convention, is right,...

Microrecording and Myostimulation

For target localization we start with microrecording. The Z-D frame localizing unit has an adapter for the microdrive. The specific microelectrode is gradually advanced through a guiding cannula until it reaches 20 mm above the level of the desired target Fig. 2 . The microelectrode is connected by short leads to a preamplifier, which increases the signal-to-noise ratio. The signal from the preamplifier is then filtered, amplified, and passed through Figure 2 Microdrive mounted in the...

Brwcrw Frames

In 1977, Theodore Roberts and a third-year medical student, Russel Brown, were responsible for developing the Brown-Roberts-Wells System BRW at the University of Utah 6 . This originally CT-based system consists of a skull base ring with carbon epoxy head posts that offers minimal CT interference. The ring is attached to the patient with screws that are tightened into the skull. The localizer unit is secured to the ring with three ball-and-socket interlocks and consists of six vertical posts...

System Description And

Stealth Station Cranial

The StealthStation system was designed by Surgical Navigation Technologies Louisville, CO , now a division of Medtronic, Inc. Minneapolis, MN . It has been described by Kurt Smith 1 and was independently evaluated by Germano 2 . System components include a Unix-based Silicon Graphics workstation, an infrared digitizer with active, infrared light emitting diodes IRLED or with passive reflector spheres, and infrared cameras Polaris, Inc. a dynamic reference frame that maintains registration...

Contributors

Department of Neurosurgery, Stanford University School of Medicine, Stanford, California, U.S.A. Eben Alexander III, M.D. Department of Neurosurgery, University of Massachusetts Medical School, Worcester, Massachusetts, U.S.A. Ahmed Alkhani, M.D. Division of Neurosurgery, University of Toronto, and Toronto Western Hospital, Toronto, Ontario, Canada Ron L. Alterman, M.D. Division of Stereotactic and Functional Neurosurgery, The Hyman-Newman Institute for Neurology and...

Which Frame Is Best

First Stereotactic Frame

The quotes around the last word sum up the answer succinctly there is no one ''best'' system or concept. Neurosurgeons or institutions seeking to purchase their first stereotactic frame may find various reasons for making a Figure 3 Cosman-Roberts-Wells CRW stereotactic system. A, MRI-compatible headring with attached Universal Compact Localizing Frame UCLF . B, Rectilinear phantom pointer RLPP with CRW stereotactic frame calibrated to phantom target. The RLPP is also used for isocenter...