Summary

The DREZ operation has provided substantial relief of pain for thousands of patients who otherwise would have continued to suffer from their condition. Many pain syndromes previously deemed untreatable'' have become more manageable. Even anesthesia dolorosa, the dreaded complication of a minority of trigeminal neuralgia procedures, can yield to the nucleus caudalis DREZ operation in a significant number of cases. The DREZ is generally not useful for peripheral etiology pain in the spinal cord...

Trigeminal Neuralgia

Leksell first described radiosurgical treatment of trigeminal neuralgia in 1971 3 . Our experience now includes more than 450 patients treated for TN with the Gamma Knife 4 . In our treatment protocol, the trigeminal root is identified on axial, coronal, and reconstructed sagittal stereotactic MR images at its point of entry into the pons. Treatment is delivered using the 4-mm secondary collimator helmet of the Gamma Unit. The treatment isocenter is placed over the trigeminal root such that the...

References

Barnett GH, McKenzie RL, Ramos L, Palmer J. Nonvolumetric stereotaxy-assisted craniotomy. Results in 50 consecutive cases. J Stereotact Funct Neu-rosurg 61 80-95, 1993. 2. Gomez H, Barnett GH, Estes ML, Palmer J, Magdinec M. Stereotactic and computer-assisted neurosurgery at the Cleveland Clinic. Review of 501 consecutive cases. Cleve Clin J Med 60 399-410, 1993. Friets EM, Strohbehn JW, Hatch JF, Roberts DW. A frameless stereotaxic operating microscope for neurosurgery. IEEE Trans Biomed Eng...

Pituitary Tumors

Microsurgery remains the procedure of choice for the rapid treatment of pituitary tumors that are causing mass effect or secreting adrenocorticotropic hormone or growth hormone. Stereotactic radiosurgery is an effective alternative for patients who do not require decompressive surgery, rapid normalization of endocrine abnormalities, or who suffer from recurrent tumors despite medical and surgical intervention. The treatment goals for pituitary tumors are control of tumor growth, cessation of...

Introduction

A scientific basis for the application of intrathecal opioids was first laid in 1970s when highly specific opioid receptors were discovered in the nervous system of rats and primates 1 . Subsequently, opioid receptors were identified in the substantia gelatinosa of the dorsal root entry zone of the human spinal cord 2 . Clinical effectiveness of intrathecal morphine was demonstrated by Wang 3 in 1979 and since then, the idea of intrathecal drug delivery for pain control has gained wide...

Intraoperative Monitoring

Rootlet selection for division is based on the electromyographic response to electrical stimulation and visible muscle contraction. The overall clinical picture is considered, and sacral-level rootlets associated with anal sphincter activity are spared. Recordings from the muscles are made from 2.5 cm. stainless-steel needles, placed two each in the anal sphincter and in five muscle groups of each leg hip adductors, quadriceps, tibialis anterior, hamstrings, and gastrocnemius. This allows...

Ii

Table 3 Comparison of 2-Year Survival Rates ( ), Stratified by RTOG-Defined Risk Groups III, IV, V, and VI Series stratified by risk Table 3 Comparison of 2-Year Survival Rates ( ), Stratified by RTOG-Defined Risk Groups III, IV, V, and VI Series stratified by risk Historical controls RTOG standard risk groups (13) SRS combined experience of Wisconsin, JCRT, and Gainesville (14) Fractionated treatment MGH-HCL (19) Numbers of patients in each group at time of diagnosis are shown in parentheses....

Discussion

The decision to use thalamotomy or thalamic stimulation is not clearcut. The advantages of thalamotomy are that it is an established technique with which there is considerable experience. The surgery is relatively more straightforward and is of shorter duration than thalamic DBS. Once the surgery is complete, there are no further concerns about hardware infection, migration, or malfunction. Furthermore, once the lesion is made, there are no adjustments to be made to the stimulator. This can be...

Psychiatric Disorders

After the introduction of classic physiologic methods to the study of the forebrain, interest turned to how the results of these studies could be applied to the clinical realm. Because of the horrid conditions within psychiatric facilities at the time and the primitive nature of nonsurgical therapies (e.g., insulin and electric shock), the advent of psychosurgery held great promise. Stereotactic variants of psychosurgical procedures have included cingulot-omy 28 , anterior capsulotomy 29 ,...

Assembling The Zd Framebased System For Surgery

5.1 Mounting the Z-D Localizing Unit The patient is prepared for mounting the Z-D unit vital signs are monitored, an intravenous (IV) line is placed for sedation with Versed 2 mg and Fen-tanyl 100 mcg, and supplemental oxygen is provided. The ring is placed in the clamps of the head holder. The patient is put on the stretcher and carefully moved into the ring. The patient's head is positioned such that the ring is parallel to the obtitomeatal line. The sites of pin placement are marked, and...

Surgical Complications

Infection risks are probably the most feared complication with the use of intraspinal opioids. Infection can occur at the pump insertion site, along the catheter track, and within the intrathecal space. The hardware must be placed under sterile technique according to manufacturer recommendations with the use of perioperative antibiotics and intraoperative antibiotic irrigation. After the initial pump filling before implantation, the first puncture to refill the pump should not be earlier than...

Electrode Internalization

If the stimulation trial is satisfactory, achieving at least 50 pain relief without intolerable side effects such as unpleasant paresthesias, the patient is prepared for electrode internalization. The final system selection (IPG vs RF receiver), which depends on optimal stimulation parameters and patient preferences, can be made before internalization. The internalization procedure is usually performed under general anesthesia, as IPG receiver insertion and especially wire tunneling are very...

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...

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...

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...

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

Microrecording

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...

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...