Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “STEREOTAXIC TECHNICS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 451 records · Page 25Linked to original sources
PubMed2001

History of lesioning for pain.

The history of open and subsequently stereotactic brain lesions for the relief of pain is traced. Important steps included recognition of the importance of the non-specific pain pathways and the differential effects of lesioning on nociceptive pain and on different elements of neuropathic pain. Although the advent of morphine infusion and deep brain stimulation has greatly eroded the number of destructive lesions made, new technical and conceptual advances must be carefully evaluated.

Chronic Disease↗
PubMedDate not supplied

[The CT-stereotaxic neutron brachytherapy of brain tumors with californium sources on the ANET-B apparatus].

A method for stereotaxic intratissue radiotherapy of brain tumors based on the findings of computed tomography is described. Radiosurgical implantation of sources with increased 252Cf content emitting mixed neutron + gamma-radiation was accomplished by means of an ANET-B apparatus by the afterloading method. Neutron irradiation is particularly effective in patients with malignant tumors possessing a large fraction of cells in a state of deep anoxia. Dosimetric planning was conducted by means of an original computer system. Devices and radiation-technical equipment for adaptation of the ANET-B apparatus for irradiation of neurosurgical patients are described. The indications for the use of this method and its place among the complex of measures for the treatment of patients with new growths of the brain are discussed. The first experience in using CT-stereotaxic neutron brachytherapy with californium sources on the ANET-B apparatus for the treatment of 6 patients with malignant glial tumors of the brain is dwelt on.

Adult↗
PubMedDate not supplied

[Preoperative approach to the histologic diagnosis of cerebral tumors by combination of clinical and paraclinical examinations (EEG, computerized cerebral tomography, scintigraphy, and angiography)].

The authors present their last series of one hundred operated cerebral tumors (19 meningiomas, 16 benign gliomas, 38 malignant gliomas, 20 isolated metastasis, 8 diversified tumors) studied on the clinical, E.E.G., isotopic scanner, computorized tomographies and angiographic point of view. The comparison of these multiple exams, permits one to determinate the malignant of benign nature of a tumor in 86 p. 100 of the cases and the precise histological nature in 56 p. 100 of the cases. The biopsy effectuated in stereotaxic conditions permits to solve the problem in uncertain cases. The interest of computorized tomography is emphasized (discovery or confirmation of a suspected tumor, definition of its extension in depth), but this recent technic is incapable of constant confirmation of the histological diagnosis; it cannot replace other confirmed methods of diagnosis. The angiography remains necessary to guide the surgical gesture.

Brain Neoplasms↗
PubMed1999

Technical advances in radiotherapy of head and neck tumors.

Future teletherapy in head and neck sites will include treatment of additional aggressive base-of-skull tumors, acoustic neuromas, and external ear canal tumors. In addition, protocols are being developed to take advantage of the enhanced precision of stereotaxic and conformal teletherapy to deliver concomitant boosts to gross or residual disease after surgery. These field-in-field boosts permit accelerated, hyperfractionated radiotherapy to be delivered to tumor, while maintaing or decreasing dose to surrounding normal tissues. The improved results of aggressive, accelerated fractionation schedules may be realized with acceptable morbidities through the use of more focused irradiation.

Brachytherapy↗
PubMed1998

[Computer-assisted surgery in the ENT specialty. Developments and experiences from the first decade].

BACKGROUND: Computer-Assisted-Surgery (CAS) names a method that allows intraoperative navigation in the surgical field based on digital image data like CT, MRT, MRA, DSA and others. A computer processes the image data in real time and is intraoperatively connected to a measuring system for coordinate determination. CAS is used in ENT surgery since 1986. The authors developed several generations of CAS systems. METHODS: In a first approach, a passive robot arm was applied. Self-developed electromechanical and infrared optical coordinate measuring devices followed. RESULTS: CAS was applied to several fields of otorhinolaryngologic surgery including the paranasal sinuses, the orbit, the rhinobasis and otobasis and other. CAS was found to be useful for surgery of acoustic neuromas, the paranasal sinuses in cases of massive disease or revision surgery, decompression of orbit or optiv nerve, extraction of deep seated foreign bodies, stereotaxy-like biopsies, for educational purposes and others. CONCLUSIONS: CAS in its current state of development is a useful tool that can be routinely applied. However, further technical development is necessary.

Computer Systems↗
PubMed1990

[Laitinen's stereo-adapter: application to the fractionated cerebral irradiation under stereotaxic conditions].

Radiosurgery is a technique which provides a single high dose of radiation very precisely to an intracranial lesion. The volume of tissue treated is small enough to avoid undue biological damage. This treatment requires very sophisticated apparatus and often considerable modifications in the treatment apparatus. The authors have closen to elaborate a system which makes it possible to deliver conventional fractionated irradiation, using a non-invasive stereotactic head frame called "Laitinen stereo-adapter". By fractionating the dose, most benign or low-grade malignant brain tumours can be treated, whatever their volume. The stereo-adapter and the target localization process are described. It can be used with C.T. scanning, angiography or M.R.I. The treatment apparatus is a linear accelerator delivering a 10 M.V. photon beam and treatment is made in the precise positioning of the target localization. The geometrical accuracy of the repeated mountings was studied in a preliminary study, showing a mean discrepancy of less than 1 mm in the three space planes. The geometrical accuracy of the radiation treatment was also studied on a phantom and the precision evaluated at less than 1 mm. The addition of extra collimators with a precollimation system decreased the lateral penumbra to 2-3 mm. Careful dosimetry was performed for each collimator. The use of non-coplanar arcs makes it possible to obtain a steep dose fall off outside the target volume. The dose planning calculations were compared to photodensitometry and thermoluminescent measurements, showing a good correlation. Each technical point will be discussed.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Neoplasms↗
PubMedDate not supplied

Accuracy of cytologic diagnosis of central nervous system neoplasms in sterotactic biopsies.

The cytohistologic correlation is reported for 112 of the 128 consecutive sterotactic aspiration biopsies performed on patients with clinical and neuroradiologic evidence of brain tumors investigated at the Neurosurgery Department, Karolinska Hospital, from 1976 to 1979. The cytodiagnostic accuracy of benign and malignant tumors was 87% when adequate cell material was obtained. In 17 benign tumors of the sellar region, the diagnostic rate was 88%; cytologic examination independent of histologic biopsy is feasible in this area. The cytodiagnostic accuracy for 95 malignant central nervous system (CNS) tumors was 87% after adjusting for the appreciable sampling error inherent in the use of a stereotactic procedure during the early phase of the study. Two histopathologically proven infectious lesions were reported cytologically as benign. The main microscopic problems were the recognition of highly differentiated astroglial neoplasms and the differential diagnosis between poorly differentiated brain neoplasms and metastases to the CNS. Cytodiagnostic accuracy of CNS tumors can be increased by technical improvements in the stereotactic device, diagnostic experience and immunochemical staining.

Biopsy, Needle↗
PubMed2005

A new stabilizing craniotomy-duratomy technique for single-cell anatomo-electrophysiological exploration of living intact brain networks.

Standard large craniotomies induce undesirable brain motions during intracellular recordings in whole animal preparations. Practically all of the papers available in the literature outline a number of specific methodological approaches designed to avoid this inconvenience. Our study describes a new craniotomy-duratomy, which consists of the maintenance of a thin bone membrane and dura mater surrounding the small hole opened for lowering the recording micropipette. This new surgical preparation avoids brain movements by keeping the brain's volume constant within the cranial cavity and does not require additional technical procedures. It is an all-purpose surgical technique, although it was developed in anaesthetized rats while studying spatio-temporal dynamics of cellular interactions associated with thalamocortical oscillations. It significantly improves both the precision of stereotaxic approaches and the success rate of single-cell recordings (e.g., current-clamp intracellular and paired recordings) compared to standard craniotomy/electrophysiology techniques.

Animals↗
PubMed2000

[Orthognathic surgery and stereolithographic models. A new technic of dental occlusion transfer].

Use of stereolithographic models in orthognathic surgery is limited by the difficult in considering the facial osteotomies and the dental occlusion at the same time. Different techniques allow the surgeon to perform the simulation using composite prototypes after including the dental casts on the models. These techniques require complex "stereotaxic" systems or a surgical approach before CT scanning in order to insert the reference screws. They cannot overcome the problem of mandibular movement during the CT session. Our technique is a simple way to include the dental casts in the stereolithographic model with high precision. This can easily be done in a maxillo-facial environment and does not require any further special knowledge other than that which can be aquired in a classical dental laboratory. The occlusion transfer is achieved with a silicon cast of the teeth and the bony structures of the sterolithographic model on which we include the plaster dental casts. The silicone cast of the dental occlusion can also be used to decrease the mandibular movement during CT scanning.

Adult↗
PubMedDate not supplied

[Stereotactic cerebral biopsy in acquired immunodeficiency syndrome (AIDS)].

Central nervous system (CNS) complications are currently described in patients with Acquired Immuno-Deficiency Syndrome (AIDS). CT-scan imaging is helpful in the description of the lesions. However, by CT-criteria alone, it is not possible to reliably distinguish toxoplasmosis from other CNS infections and from a primary CNS sarcoma. The authors consider that biopsy of the lesion is recommended to exclude other treatable diseases such as bacterial infections, tuberculosis, fungus and toxoplasmosis. Stereotactic technic gives the optimal precision and security.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Preliminary experimental investigation of in vivo magnetic manipulation: results and potential application in hyperthermia.

The first in vivo experiments in support of a new technique for delivering stereotaxic hyperthermia have been conducted at the Experimental Surgery Facility of the University of Virginia's Medical Center. We call this technique the "Video Tumor Fighter." In each of twelve trials a single, small permanent magnet or train of small permanent magnets was implanted on the brain surface of adult canine models. In three of the trials, this "seed" (typically 6-mm diameter X 6-mm long) was moved by magnetic manipulation to different locations within the brain. In two other trials, the seed moved along the interface between the brain and the inner vault of the skull. The noncontact magnetic manipulation was accomplished by coupling the permanently magnetized seed to the large dc magnetic field gradient created by a water-cooled coil surrounding the animal's head. The seed's motions were monitored with x-ray fluoroscopy; its rate of movement was found to be approximately 0.8 mm s-1. The forces required to produce these motions were on the order of 0.07 N. We document here the instrumentation used in these trials, describe the experimental procedures employed, and discuss the technical aspects of the results.

Animals↗
PubMed1999

Staged functional neurosurgery using image fusion: electronic atlas and microelectrode recording at Dundee.

The unforgiving nature of the thalamus, the globus pallidus and the subthalamic nucleus necessitates precise localization of functional targets. This requires the total attention of both the patient and the surgeon. To maximize the concentration of the patient and provide the most accurate localization, we performed staged stereotactic functional procedures. The first stage was performed under general anesthesia to abolish any head movement. We fused CT and MRI images and correlated the fused images with a digitized Talairach brain atlas. We calculated the target coordinates and fixed a modified Bennett Sphere to the skull with the central hole defining the trajectory to the target. The surrounding 12 holes gave parallel trajectories to targets surrounding the anatomical target at 2-mm intervals. The second stage was performed at least a week later under local anesthesia. Microelectrode recording using three simultaneous channels was used to refine the target. Once the microelectrode recordings and macrostimulation confirmed the desired target, a lesion was created or an Activa neurostimulator was inserted. Our early results using this technique in 28 procedures (in 19 patients) indicate a good outcome in 86% and a technical failure in 1 patient.

Diagnostic Imaging↗
PubMed2003

Semiautomatic core biopsy. A modified biopsy technique in breast diseases.

PURPOSE: To evaluate a semiautomatic gun to retrieve diagnostic core specimens of lesions in the breast and the axillary region. MATERIAL AND METHODS: In a series of 180 consecutive core biopsies (2.1 mm), 145 (142 breasts and 3 axillae) were performed with a semiautomatic gun (18 stereotaxic and 127 US-guided) from lesions presenting mammographically as microcalcifications (n = 15) and opacities (n = 130). The gun did not work satisfactorily in 34 lesions, which were tumors with a very hard consistency. One additional patient was excluded because of technical failure. Biopsy diagnoses in the 145 patients were correlated to surgical histopathology, follow-up mammograms and/or clinical findings. RESULTS: Histologic examination of the specimens resulted in correct diagnoses in 89% (129/145) of the total material and in 87% (108/124) of cancers. In 107 cases, in which only 1 specimen was obtained, 83 of 89 cancers (87%) were detected. Length of specimens ranged from 3 mm (n = 2) to 17 mm (n = 31). Among patients with a 17-mm-long specimen, there was only 1 false-negative diagnosis. CONCLUSION: The semiautomatic gun provided diagnostic specimens in a majority of cases and could be used as an alternative to the automatic guns when size or location of the lesions necessitates a high precision. It was not suitable for use in very hard tumors.

Adult↗
PubMed1986

[Treatment of abnormal movements by thalamic lesions].

Thalamic targets in the treatment of involuntary movements include the lateral and usually the intermediary ventral nuclei. Destruction of their afferents in Forel's fields provides the same therapeutic result but the size of the lesion must then be very small due to the proximity of essential structures, particularly corpus Luysi. Efficacy of treatment depends partly on the aetiology of the involuntary movement (and thus from the indication for surgery) and also on the technical possibilities of electrophysiologic mapping. The true dystonic element of the involuntary movement is usually little improved whereas tremors of all types are improved or suppressed. Essential tremor, familial or not, of large amplitude and very disabling, is an ideal indication for stereotaxic surgery when it presents as intention tremor. In Parkinson's disease, the treatment is effective against tremor and rigidity but akinesia is unaltered and the progressive course of the disease uninterrupted. Indications for surgery have become rare since the availability of L-dopa, perhaps too rare for the slowly progressive forms with predominant tremor poorly relieved by dopa-therapy, surgery has a curative and probably preventive effect on the involuntary movements of limbs induced by this treatment. Suppression of post-traumatic tremor and that due to multiple sclerosis is dependent on various factors: electrophysiologic precise mapping of the target since "electrical silences or holes" exist that disturb or prevent collection of evoked potentials or spike activity; multiple neurologic lesions that may be worsened by an additional thalamic lesion; finally residual cerebellar disturbance unmasked by the suppression of tremor, a poor "functional" result despite a good operative result.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Injuries↗