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At least 541 records · Page 30Linked to original sources
PubMed1990

[Interstitial brachytherapy for malignant gliomas using the Brown-Roberts-Wells (BRW) stereotactic system].

Eleven patients harboring recurrent or deep-seated malignant gliomas were treated by interstitial brachytherapy with 192Ir seed assembly, between June 1987 and September 1989. Implantations for the afterloaded catheter were performed using the Brown-Roberts-Wells (BRW) CT guided stereotactic system. The number of seeds and the distribution of the implants were chosen in such a way that the minimum tumor dose of 30-50Gy could be delivered to the surface or 1cm beyond the rim of the contrast enhancement. The radioactive sources were held in the afterloaded catheters that were removed after the desired dose had been delivered. Response to therapy was measured by serial CT scans and clinical examination. Tumor regressions were seen by CT scans made 2 or 3 months after implantation. One tumor showed complete regression (CR), four showed partial response (PR), one showed minor response (MR) and 5 showed no change (NC). Overall response rate was 54%. Six patients died 3 to 18 months following implantation, and five are still alive 7 to 27 months after implantation. No complications such as infection or hemorrhage were observed during the treatment. A patient harboring large (6.5cm in diameter) recurrent glioblastoma in the rt. parietal robe required a craniotomy due to the mass growing for one and half month after implantation, and radiation necrosis of the entire tumor mass was documented. The technique of stereotactic interstitial implantation was clinically well tolerated and easily reproducible and our preliminary results seemed encouraging. Technical improvement to achieve an adequate isodose distribution to cover the tumor volume might lead to improved survival rates.

Adolescent↗
PubMed1996

Stereotactic breast biopsy: a practical approach.

The continuing increase of women participating in mammographic screening has resulted in a rise in the number of nonpalpable abnormalities identified. The development of minimally invasive and cost-effective methods to achieve accurate histologic diagnosis is needed. Stereotactic needle core biopsy had been used to reduce the number of women requiring needle-directed open surgical biopsies for benign disease. The team approach is essential for implementation of these newer diagnostic and interventional modalities. The surgeon has always taken the responsibility for coordinating the diagnostic and treatment components of appropriate breast care. Therefore, surgeons must continue to integrate new technology into their practices. The extensive experience of more than 3000 stereotactic biopsies performed at The Breast Center has provided the background for discussing the technical aspects of the procedure. The appropriate workup and subsequent indications for patient selection are reviewed. Pre and postprocedural patient considerations are addressed. This should provide an introduction to the basic principles of stereotactic needle core biopsy for implementation into a surgical practice.

Biopsy, Needle↗
PubMed2000

Stereotactic radiosurgery for acoustic neuromas: a survey of the American Neurotology Society.

OBJECTIVE: The purpose of this study was to better understand the complications, outcomes, and surgical difficulties in treating acoustic neuroma patients who have undergone stereotactic radiosurgery (SRS). STUDY DESIGN: A six-page, 28-item questionnaire was mailed to 395 members of the American Neurotology Society. SETTING: The study was conducted through an academic neurotologic practice. Questionnaire respondents were neurotologic physicians in private and academic practice. PATIENTS: A total of 46 patients who had undergone SRS were evaluated. INTERVENTIONS: Twelve (26%) of the 46 patients required microsurgery after SRS. MAIN OUTCOME MEASURES: Posttreatment cranial nerve status and the development of complications such as cerebrospinal fluid leak, meningitis, and cerebrovascular accident were evaluated. RESULTS: In the group of 12 patients who underwent microsurgery after SRS, 11 patients had some form of postoperative facial paralysis. Anacusis was present in all 12 patients. Two of the 12 patients had new-onset trigeminal neuropathy postoperatively. CONCLUSION: Microsurgical resection of acoustic neuroma after SRS is technically difficult. The difficulty exists regardless of the time of microsurgical resection after SRS. Patients who underwent microsurgery after SRS had uniformly poor cranial nerve results.

Adolescent↗
PubMed2001

Does exhaustive search for microcalcifications improve diagnostic yield in stereotactic core needle breast biopsies?

Stereotactic core needle biopsy (SCNB) of the breast is a cost-effective alternative to needle localization biopsy for the diagnosis of mammographic calcifications. We questioned whether an exhaustive search for calcium in the small samples obtained in SCNB yields more diagnostic information than that obtained with examination of a standard number of sections. We retrospectively reviewed 168 specimens from 123 patients with mammographic calcifications, including cases in which radiographic suspicion ranged from low to high. Microcalcifications were identified on three initial levels in 112 specimens. Additional sections were examined in 50 specimens. The final diagnosis differed from the diagnosis based on three levels in 11/50 cases (22%). In 6/50 (12%), complete sectioning yielded a specific diagnosis. The increase in technical cost associated with the additional levels was 414% per case. We conclude that exhaustive searching for microcalcifications in SCNB yields a small increase in specific diagnostic information and a high technical cost. In individual cases, the additional information may be critical for appropriate patient management.

Biopsy, Needle↗
PubMed2005

Microsurgical anatomy of the transcallosal anterior interforniceal approach to the third ventricle.

OBJECTIVE: We explored relevant regional microanatomy as it relates to the challenging anterior interforniceal (AIF) approach for removing hypothalamic hamartomas. METHODS: Five silicone-injected cadaveric heads were dissected by use of frameless stereotactic navigation to reveal microanatomy and extent of exposure through the transcallosal AIF approach. Distances between trajectories to the coronal suture and the genu of the corpus callosum (CC) and between the posterior border of the anterior commissure to the lower end of the rostrum of the CC and posterior border of the foramen of Monro were measured. RESULTS: The AIF approach provided adequate access to the anterior third ventricle and related structures (i.e., hypothalamus, infundibular recess, and mamillary bodies) through the corridor bounded by the anterior commissure anteriorly and the choroid plexus at the foramen of Monro posteriorly. The mean distances from the posterior trajectory to the coronal suture and the genu of the CC were 44.8 mm (range, 43.8-46.2 mm) and 14.88 mm (14.1-15.7 mm), respectively. The mean distance from the anterior trajectory posterior to the coronal suture was 4.66 mm (0-8.9 mm), and 32.6 mm (30.5-33.9 mm) to the genu of the CC. The mean length of callosotomy was 17.52 mm (16.2-19.1 mm). The mean distance between the posterior border of the anterior commissure and the lower end of the rostrum of the CC was 5.22 mm (4.6-5.6 mm), and 10.52 mm (9.7-11.5 mm) to the posterior border of the foramen of Monro. CONCLUSION: The technically safe AIF approach permitted limited interforniceal splitting, no major deep vein manipulation, and adequate visualization of the hypothalamus, infundibular recess, and mamillary bodies.

Cadaver↗
PubMed1996

Volumetric reconstruction and stereotactic computer assisted resection in intracerebral lesions.

Since 1990 112 patients have undergone stereotactic resection of intra-axial tumoural lesions with volumetric reconstruction, using the Kelly-Goerss system. Stereotactic integration of CT, angiographic and particularly MRI information, together with three-dimensional information of the lesion, provide an innovative evaluation of the most appropriate surgical approach, even for each single patient. The main limitation of this surgical method is in cases where the infiltrating part of the tumour is pre-eminent, while it can allow "macroscopically complete resection" of well circumscribed lesions, almost independently of their location and volume. Some technical aspects of stereotactic resection of brain tumours are discussed in the light of our experience.

Adolescent↗
PubMed1990

Stereotactic craniotomy.

Computed tomography-based stereotactic biopsy procedures for diagnosing intracranial tumors are common today. In addition, point stereotaxis is used to center a craniotomy over a superficial lesion or to find a deep one. Technical innovations have improved performance of these operations. The author describes the instrumentation and current methodology for computer-assisted stereotactic laser microsurgical extirpation of intra-axial lesions and discusses the results.

Brain Neoplasms↗
PubMed1995

[Symptomatic glial cysts of the pineal gland: report of two cases and review of the literature].

Referring to two individual cases, the authors review clinical, radiological and histological features of benign glial cysts of the pineal gland. Both patients were young females with aggravating headaches and with convulsions in one case. Symptoms were referable to a space-occupying cystic mass of the pineal gland. On histology, both lesions proved to be non neoplastic cysts without an epithelial lining. Their histogenesis and low growth potential were reinforced by immunohistochemical analysis of pineal antigens and proliferation markers. Glial cysts of the pineal gland are not infrequent, but symptomatic occurrences are exceptional. Most glial cysts are of dysontogenic or degenerative origin. Sometimes, however, the role of hormonal influences or paraneoplastic factors must be considered. Symptoms caused by glial cysts of the pineal gland are non-specific and radiologic imaging technics may contribute little to etiologic diagnosis. Pineal cysts are curable by surgical resection or stereotactic decompression. Whatever the diagnostic approach, emphasis must be laid on the histologic examination in order to avoid unnecessarily aggressive treatment.

Adolescent↗
PubMed1993

Technical possibilities and limitations of stereotaxy.

The availability of CT-Scanners and MRI coupled to stereotactic systems has made a stereotactic neurosurgical intervention an everyday tool. The indications, contra-indications and complications concerning intracranial tumours, the hypophysis, combined open stereotactic procedures, third ventriculostomy, diseases of the extrapyramidal motor system, pain, epilepsy, psychosurgery and the transplantation of embryonal cells are discussed.

Biopsy↗
PubMed1998

Multiple neuroanatomical tracing in primates.

The present report deals with a multiple tract-tracing procedure in non-human primates enabling the simultaneous visualization of retrogradely transported Fluoro-Gold (FG) and cholera toxin B subunit (CTB) in combination with anterogradely transported biotinylated dextran amine (BDA). Two issues have played key roles on the achievement of this reliable procedure: first, the recent development of a commercial antiserum against FG that allows us to convert the original fluorescent signal of this dye in a permanent precipitate via standard peroxidase-anti-peroxidase methods; second, the introduction of the novel peroxidase substrate Vector(R) VIP (V-VIP), resulting in a purple precipitate. The combination of these neuroanatomical tracers in one and the same histological section opens a possibility for the permanent visualization of the convergence of inputs from a particular brain area onto identified, two different subsets of projection cells of another area. Furthermore, this combination of three tracers emerges as a powerful technical tool for obtaining broad amounts of complementary data regarding the monkey brain connectivity, thus significantly reducing the number of animals needed to complete a particular study.

Animals↗
PubMed1993

Quantification of central benzodiazepine receptor binding potential in the brain with 123I-iomazenil SPECT: technical and interobserver variability.

Factors contributing to the quantification of the central benzodiazepine receptor binding potential in vivo using 123I-iomazenil and single photon emission computed tomography (SPECT) were analysed in phantom studies and in volunteers. SPECT was performed with the SME810 multidetector system. The Hoffman three-dimensional brain phantom was used to investigate linearity and reproducibility of SPECT results using different 123I activity concentrations. Dynamic and multislice SPECT scans were performed in nine healthy volunteers between 0 and 270 min after injection of 110 MBq 123I-iomazenil. Displacement studies were performed in three volunteers using 1 mg flumazenil administered intravenously (i.v.) at 250 min postinjection (p.i.). Regions of interest (ROIs) over the cerebral cortex and various subcortical nuclei were either fixed areas based on a stereotaxic brain atlas, or manually drawn, based on 60% isocontour lines. Interobserver variability of the ROI data and ratios derived from those data were estimated for two independent observers. The brain phantom measurements showed linearity with respect to 123I concentration and good reproducibility. The interobserver study showed a reasonable interobserver reliability for the large fixed ROIs. The displacement study showed about 50% displacement in all ROIs. Concentrations of 123I-iomazenil in the brain can be measured reliably with the SME810. Large fixed ROIs based on a stereotaxic atlas may be used reliably for quantification. The level of 4 cm above the cantomeatal line does not provide a useful reference region with a very low central benzodiazepine receptor binding potential.

Adult↗
PubMed1994

A stereotactic guide for microsurgery. Technical note.

A stereotactic guide for microsurgery is presented. The guide consists of a weak helium neon laser projecting a red beam towards the target when the arc carrying the beam has been set on the Leksell frame according to the stereotactic co-ordinates of the target calculated on the pre-operative imaging studies. The device allows free manoeuverability of the operating microscope.

Brain Diseases↗
PubMed2000

The present and future of cerebral tumor surgery in children.

Cerebral hemisphere tumors are less common than posterior fossa tumors in children, but are still important among childhood tumors. At the present time, many are low grade and can be treated satisfactorily with modern surgical techniques. These techniques include image-guided surgery in the conventional operating room, brain mapping, and surgery in the intraoperative MRI. Technical sophistication is the chief characteristic of present approaches to cerebral cortical tumors. In the future, surgery for these tumors will require both technical and biological sophistication. Malignant cerebral tumors are invasive and heterogeneous and require new understandings of biology to develop effective treatments. These biological understandings will be added to sophisticated surgical techniques for surgical resection, perhaps with local delivery methods.

Brain Mapping↗
PubMed1994

Stereo-electroencephalography methodology: advantages and limits.

Since January 1990, 70 patients with medically intractable partial epilepsy underwent a stereo-EEG investigation in our center. We first described technical requirements, and gave an overview of the variety of the explored cerebral regions and implantation patterns realized, pointing out the low rate of morbidity (1.4%). The three-dimensional epileptogenic zone thus defined led to a tailored individualized surgical excision in 60 patients, while 9 are waiting for surgery and the remaining 1 has been excluded (1.4%). Conceptual and technical aspects of the stereo-EEG methodology were discussed in order to underline its peculiarities in the field of "depth recordings", and more generally among the broader group of "invasive" procedures.

Adolescent↗
PubMed1997

[Stereotactic surgery in Parkinson's disease].

Stereotactic surgery for Parkinson's disease (PD) has regained interest due to the recently described hyperactivity of the subthalamic-pallidal pathway. Many patients suffering from complications associated with the chronic use of levodopa may benefit from surgical treatments. There are different surgical targets and techniques (ablative and deep brain stimulation). The choice of one particular target and technique relies on the clinical symptoms of the patient. The risk/benefit ratio of surgery is related to the careful selection of patients and the technical accuracy. Intraoperative microrecording is considered the best method to avoid side effects and partial results. A series of patient's selection and follow-up assessment criteria are proposed.

Follow-Up Studies↗
PubMed1993

Modifications of the compass stereotactic magnetic resonance localizer: technical note.

Head size, shape, or optimal anterior support placement can preclude stereotactic localization using the Compass magnetic resonance imaging (MRI) localizer. The described modifications of MRI localization largely overcome these limitations and should allow for safer, more versatile MRI stereotactic localization with the Compass system in more patients than using standard techniques.

Equipment Design↗
PubMed1975

Destruction of small intracranial tumours with 60Co gamma radiation. Physical and technical considerations.

The clinical and physical conditions for the destruction of small intracranial tumours by means of multiple gamma beam irradiation are evaluated. The effects of the collimation of the single beam and the spatial distribution of 179 beams on the superimposed three-dimensional dose distribution are investigated experimentally and theoretically. Techniques for selective irradiation of tumours of various types and sizes are discussed.

Brain Neoplasms↗
PubMed1994

Chronic neurogenic pain and the medial thalamotomy.

69 patients suffering from chronic therapy-resistant neurogenic pain of peripheral and/or central origin underwent a stereotactic medial thalamotomy. Medial thalamic unit recordings were performed peroperatively, allowing the physiological confirmation of the electrode location and the recognition of a specific physiopathology. Thanks to these recordings, a concept was developed, based on the presence of an imbalance between medial (nucleus centralis lateralis mainly) and lateral (nucleus ventroposterior) thalamic nuclei, resulting in an over-inhibition of both by the reticular thalamic nucleus, and then in a paradoxical activation of pain-related cortical areas. The medial thalamotomy, re-actualized by new technical, anatomical and physiological data, offers a 50-100% relief to 67% of all patients with peripheral as well as central neurogenic pain, on all body localizations, without producing neurological deficits and without risk for the development of iatrogenic pain.

Adult↗