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Results for “STEREOTAXIC TECHNICS”

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At least 649 records · Page 36Linked to original sources
PubMed1988

Cerebral angiography under stereotactic conditions. Technical note.

A simple system for cerebral angiography under stereotactic conditions using standard components is described. X-ray tubes and power generator belong to the usual equipment of the stereotactic operating room. A film changer and an injection pump were integrated into the stereotactic arrangement. Angiographic documents with reduced X-ray magnification were obtained. For topographical orientation 5 films per seriogram were sufficient. The system also allows stereoscopic viewing by performing an additional oblique sequence after the head ring is rotated exactly 6 degrees. The combination of the necessary diagnostic procedures, as CT scan, angiography, ventriculography, serial biopsy within a single three coordinate reference system offers considerable advantages for brain tumour patients.

Adolescent↗
PubMed1996

Magnetic resonance image-guided stereotactic cingulotomy for intractable psychiatric disease.

We describe the modern operative technique of magnetic resonance (MR) image-guided stereotactic cingulotomy and discuss the indications, results, and complications of this procedure. A retrospective analysis of psychiatric outcome was performed for 34 patients with intractable major affective disorder and/or obsessive-compulsive disorder who underwent MR image-guided stereotactic cingulotomy since 1991. Fourteen patients underwent multiple cingulotomies (50 total procedures). Overall, 38% of the patients were classified as responders, 23% as possible responders, and 38% as nonresponders. Of the patients who did not respond to initial cingulotomies and who underwent multiple cingulotomies, 36% became responders, 36% possible responders, and 28% nonresponders. There were no deaths or long-term side effects related to the procedure. The therapeutic results of MR image-guided stereotactic cingulotomy are similar to the results of earlier methods of cingulotomy, and the use of MR imaging offers substantial technical advantages. This procedure also compares favorably with other neurosurgical procedures performed for intractable psychiatric disease with a low rate of undesired side effects. Cingulotomy is safe and well tolerated, with over one-third of the patients demonstrating significant improvement; however, prospective long-term follow-up studies are needed to further define the role of surgery in treating intractable psychiatric disease.

Adolescent↗
PubMed1997

Volumetric magnetic resonance imaging. Clinical applications and contributions to the understanding of temporal lobe epilepsy.

In recent years, magnetic resonance imaging-based volumetric measurements of the amygdala and hippocampus have proved useful in the diagnosis and treatment of patients with temporal lobe epilepsy. This imaging modality allows amygdaloid and hippocampal volumes to be correlated with neurophysiological, neuropathological, and neuropsychological findings, surgical outcome, and clinical findings. We evaluated the technical and anatomical aspects underlying the successful use of the modality that were reported in previous studies. We also evaluated issues such as the sensitivity and specificity of volumetric magnetic resonance imaging, its use in bilateral temporal lobe epilepsy, and the debate concerning the sensitivity of qualitative visual analysis vs quantitative volumetric analysis of magnetic resonance images. Volumetric magnetic resonance imaging, when used in conjunction with video electroencephalographic monitoring, neuropsychological studies, and other neuroimaging studies, will enable patients with temporal lobe epilepsy to be treated in an appropriate, efficient, and cost-effective manner.

Amygdala↗
PubMed2002

Imaging of subthalamic nucleus and ventralis intermedius of the thalamus.

The techniques of targeting the subthalamic nucleus (STN) and the ventralis intermedius nucleus (Vim) are similar, only the coordinates are different. Targeting ideally consists of gathering all data about a target and positioning the electrode correctly within that target. The electrode should be positioned within a statistical range of coordinates, where the neuronal firing fits a given pattern and responds to external stimuli, particularly to proprioceptive inputs, in a somatotopically organized manner. Moreover, final placement should provide the best clinical improvement of symptoms under the stimulation parameters expected to be used in the long term. This latter criterion is by far the most important, because intraoperative findings indicate the functional benefit for the patient, which is the ultimate purpose of this surgery. A variety of radiological modalities are available to provide data for electrode placement, but each type has its drawbacks. Ventriculography, although safe when performed accordingly to strict technical procedure, is the most precise method but provides more indirect targeting and is more invasive than magnetic resonance imaging (MRI). MRI is the best method for visualizing the STN and, to some extent, for discerning the Vim, but it is plagued with unpredictable and nonreproducible deformations that induce a systematic distortion. These shortcomings no doubt will be corrected in the near future, and the technologies will better assist us in the proper placement of electrodes, which will provide the patient with the highest possible benefit.

Cerebral Ventriculography↗
PubMed2000

Experience with the advanced breast biopsy instrumentation system.

OBJECTIVES: To report early experience with the advanced breast biopsy instrumentation (ABBI) system and to compare the results with those of other published studies. DESIGN: A nonrandomized case series. SETTING: An outpatient breast diagnostic centre at a large urban community hospital. PATIENTS: Thirty-four women; 27 had suspicious calcifications, 2 had a nonpalpable mass and 5 had both. INTERVENTION: The ABBI procedure to excise a breast lesion or obtain a representative sample for histologic examination. MAIN OUTCOME MEASURES: Success of the procedure with respect to diagnosis, sample quality, technical problems, margins of tumour free tissue and patient satisfaction. RESULTS: Malignant tissue was diagnosed in 7 women (21%) and atypical ductal hyperplasia in 2 (6%). In all cancers, the obtained samples had malignant cells present at the margins or less than 1 mm away. Technical problems were encountered in 32% of cases. Manual extraction of the specimen was required in 21% of cases. CONCLUSIONS: The preliminary data correlate well with those of other published results. Although it is possible that a small number of cases and a relatively high proportion of technical difficulties may represent a normal learning curve, there is a definite need for improvement of some ABBI components. ABBI does not appear to provide adequate margins of uninvolved tissue in patients with cancer and thus should not be used with curative intent. ABBI provides excellent quality samples for pathological study and good patient satisfaction. There are not yet enough data for meaningful comparison of ABBI with stereotactic core biopsy and excisional biopsy with needle localization.

Adult↗
PubMed1993

A stereotactic device for experimental gamma knife radiosurgery in rats. A technical note.

A rat stereotactic device was designed for use in Gamma Knife radiosurgery. Experimental radiosurgical lesions were made in superficial and deep cerebral structures to verify the accuracy of the coordinate system, which is based on a standard rat stereotactic atlas. Calculated dosages were shown to be accurate utilizing thermoluminescence dosimetry. Two additional features of the device permit the surgical positioning and placement of electrodes, and postmortem slicing of the brain according to the same coordinate system. This new apparatus allows precise and repeatable gamma irradiation of the rat brain without the need for expensive and time-consuming imaging techniques. Studies of this type will provide a rapid means for examining the effects of radiosurgery on the central nervous system.

Animals↗
PubMed2006

Gamma knife radiosurgery for epilepsy related to dysembryoplastic neuroepithelial tumor.

Dysembryoplastic neuroepithelial tumor (DNT) is a well-known epileptogenic lesion with favorable seizure outcome after surgical resection. However, sometimes surgery may be difficult technically, and epilepsy may continue throughout the patient's lifetime despite surgical intervention. We report a case of intractable epilepsy related to DNT that was treated with gamma knife radiosurgery (GKRS). The frequency of seizure was reduced remarkably after GKRS, and finally a seizure-free state was accomplished in two years. Neuropsychological tests also showed improvement. It is suggested that GKRS may be an effective and less invasive alternative treatment for the patients in whom surgical treatment is difficult.

Brain↗
PubMed2001

Operations using a frameless stereotactic system with a marker: technical note.

One of the most critical problems in navigation systems is that of brain shifts during operations. In order to solve this problem, we developed a simple method using a marker placed prior to microsurgery to provide a reference point. We produced a thin probe. After the dural incision, the probe, covered with a silicone tube, was inserted into the target point. Then only the probe was removed, leaving the silicone tube in place. This tube moved together with the brain, which deviated during the operation, and throughout the operation indicated the same point as that which it was pointed at first. This result suggests that this is a simple and useful method to allow navigation systems to accommodate brain shifts during operations.

Biopsy↗
PubMed2000

Microelectrode-guided thalamotomy for Parkinson's disease.

OBJECTIVE: To describe the outcomes in our first 40 microelectrode-guided thalamotomies for parkinsonian tremor. METHODS: Twenty-four left-sided and 16 right-sided thalamotomies were performed between October 1984 and January 1996; the mean follow-up period was 35.8 months (range, 1-152 mo). The results were evaluated retrospectively and semiquantitatively by a disinterested observer (MNL) and correlated with the quality of the microelectrode recording and the number and size of radiofrequency lesions made. The first 20 and second 20 procedures were evaluated separately. RESULTS: At the last follow-up, the Unified Parkinson's Disease Rating Scale showed no or virtually no tremor in the upper limb in 75% of patients or in the lower limb in 73% of patients. No significant persistent complications were found. These results were achieved at the expense of having to repeat the procedure on 11 sides (in 5 because of technical problems and in 6 for no obvious reason). Total or nearly total abolition of tremor occurred after the first procedure in 40% of the first 20 operations and in 65% of the second 20. Eight of the first 20 procedures and 2 of the second 20 failed for technical reasons. Lesions were made larger in the second 20 procedures than in the first 20. With the use of an electrode with a 1.1 x 3-mm bare tip for 60 seconds, it seems that lesions had to be created at 60 degrees C or more to produce a successful result. CONCLUSION: Thalamotomy with microelectrode recording is an effective procedure with which to treat tremor in patients with Parkinson's disease and may involve fewer complications than conventional techniques. The procedure appears to involve a learning curve.

Adult↗
PubMed1988

Closed biopsy of the spine using a stereotactic biopsy forceps. Technical note.

A new technique for closed biopsy of the spine is presented. Using a stereotactic biopsy forceps, which is advanced to the lesion through a protective puncture cannula, sufficient samples from different sites of the lesion can be obtained. Biopsy was performed in seven patients harbouring osteolytic and osteoplastic lesions of the cervical (3 cases), thoracic (3 cases) and lumbar spine (1 case). Histological diagnosis was possible in five patients. In all of them, metastatic disease was found. In our opinion, using this device closed biopsy of the spine is a simple and efficient method for obtaining sufficient material at different levels of the spine and at different sites within a lesion. We recommend its use when the therapeutic consequences--surgical tumour removal with stabilization, stabilization alone or radiation therapy--is contingent on the histopathological diagnosis.

Aged↗
PubMed1995

Real-time ultrasound imaging of cerebral lesions during "target point" stereotactic procedures through a burr hole. Technical note.

Stereotactic burr-hole procedures like biopsies of brain tumours based on CT scan or MRI and angiographic data have so far usually been carried out without real-time ultrasound image control. Intra-operative real-time ultrasound imaging was carried out during twelve target-point stereotactic procedures via a single standard burr-hole using a new slender ultrasound transducer with a diameter of 8 mm. The technical parameters of the transducer are: frequency range of 5 < - > 3.5 MHZ, phased array sector scan, 90 degree sector. The transducer has a bayonet-like configuration and can be sterilized. Sufficient quality of the images was achieved in these twelve cases with different pathological entities such as malformation cysts (3 cases), gliomas (7 cases), one metastasis and one intracerebellar haemorrhage. Moreover, co-ordinate values may be calculated from the ultrasound images generated peroperatively, allowing the surgeon to choose additional targets. Colour flow mapping provides the visualization of vascular structures. For the beginner stereotaxy may be easier to learn using ultrasound real-time imaging.

Biopsy↗
PubMed1989

[Radiation treatment of intracranial arteriovenous malformations--experiences with a semi-stereotactic technic].

Since 1982 79 patients with intracranial AVM's were irradiated at linear accelerator with 10 MV photons. Diagnosis, localization and therapy were done immobilizing the head for identical positioning. In a controlled study the therapy was done with fractionated irradiation up to 50 Gy in 25 fractions within 5 weeks or with 20 Gy in 4 fractions within 7 days. Complications, due to therapy, did not occur. Suffering from convulsion was not affected. Five patients have died, one patient got a hemorrhage 36 months later. The angiographical analysis of the first 25 patients until 30 months after radiotherapy gave complete obliterations and reduction of volume in more than 50% with minor AVM's. The result are not detrimental compared with a group after photon irradiation.

Adolescent↗
PubMed2006

MR-guided breast biopsy and hook wire marking using a low-field (0.23 T) scanner with optical instrument tracking.

The purpose of this study was to evaluate the technical feasibility of MR-guided percutaneous breast biopsy (LCNB) and breast hook wire marking in a low-field (0.23 T) MRI system with optical instrument tracking. MR-guided core biopsy and/or hook wire marking was performed on 13 lesions observable at MR imaging only. Seven breast LCNBs and 10 hook wire markings were performed under MR guidance on 11 patients. The diagnosis was confirmed by excision biopsy or mastectomy in 12 lesions and with histopathological and cytological diagnosis and 12-month clinical follow-up in one lesion. All lesions seen in the high-field scanner were also successfully identified and targeted in the low-field scanner. The following procedures were typically technically successful. There were difficulties due to unsatisfactory functioning of some core biopsy guns. Detailed description of low-field MR guidance and optical tracking in breast biopsies is provided. The procedure seems accurate and safe and provides means to obtain a histological diagnosis of a breast lesion only seen with MRI. The low-field biopsy system is comparable to the high-field MRI system. MR-compatible biopsy guns need to be improved.

Adult↗
PubMed1991

Technical application of stereotactic irradiation in malignant brain tumors.

This study reports the technical application of stereotactic interstitial brachytherapy for malignant gliomas in two groups of patients. Group I consisted of 2 patients who had undergone previous debulking brain surgery; group II were 3 patients who were not candidates for craniotomy because their tumors were surgically inaccessible. The stereotactic implantation technique in group I was somewhat complicated due to the irregular shape of the residual tumor masses. Sophisticated pre-implantation planning was necessary for adequate coverage of the entire tumor volume. In this series, inoperable tumors were also successfully implanted with excellent results.

Brachytherapy↗
PubMed1994

Stereotactic biopsy for intrinsic lesions of the medulla through the long-axis of the brainstem: technical considerations.

The authors report the technique and results for stereotactic biopsy of intrinsic lesions of the medulla oblongata through the long-axis of the brainstem. Multi-planar stereotactic magnetic resonance imaging and/or reformatted computed tomography imaging is used for coordinate determination and trajectory selection and facilitates a completely intra-axial pathway through critical neural tissue. Two patients with small, solitary, enhancing lesions of the medulla had stereotactic sampling via this approach performed under local anesthesia. There was no morbidity and in both the patients a histologic diagnosis of lymphoma was obtained. We believe that with high-resolution, multi-planar stereotactic imaging, small lesions in the medulla can safely be biopsied, avoiding the need for either posterior fossa craniectomy and open biopsy, or for empiric management.

Biopsy, Needle↗
PubMed2003

Intraoperative functional MRI as a new approach to monitor deep brain stimulation in Parkinson's disease.

This article deals with technical aspects of intraoperative functional magnetic resonance imaging (fMRI) for monitoring the effect of deep brain stimulation (DBS) in a patient with Parkinson's disease. Under motor activation, therapeutic high-frequency stimulation of the subthalamic nucleus was accompanied by an activation decrease in the contralateral primary sensorimotor cortex and the ipsilateral cerebellum. Furthermore, an activation increase in the contralateral basal ganglia and insula region were detected. These findings demonstrate that fMRI constitutes a promising clinical application for investigating brain activity changes induced by DBS.

Aged↗
PubMed1998

Superimposed holographic image-guided neurosurgery. Technical note.

Computerized tomography scanning-derived narrow band reflection holograms of patients undergoing craniofacial procedures were created to evaluate the applicability of superimposing these three-dimensional images (3-D) on the operative field during neurological surgery. These sterilized radiological holograms were positioned over the surgical site by using bone sutures as registration points between the skull and the 3-D image to serve as a visual template between the patient and surgeon. Surgeries were then performed with the surgeon looking through the radiological hologram at the patient. Holograms were accurate to within 2 mm (plus or minus) of the actual calvarial anatomy. The use of the holographic image as a visual guide during surgery eliminated intraoperative guesswork or free-handed contouring. To the author's knowledge, this is the first report of the superimposed holographic image used in situ during surgery.

Craniofacial Dysostosis↗
PubMed1979

Techniques for the lesion of the vomeronasal organ of the rat.

Two technical procedures were developed in order to suppress the vomeronasal organ (V.O.) of the rat. The organ was approached through the nasal or oral cavity and electrolytic or thermic lesions were respectively performed. For electrolytic lesions the projection of the organ on the nasal bone was first determined. After opening the nasal bones, the Vs. Os. were lesioned by way of an electric current applied through an electrode introduced between the mucosa and nasal septum. For thermic lesions, the projection of the V.O. on the palate's surface was determined. After opening this area and the underlying part of the maxillary bone, both Vs. Os. were cauterized.

Animals↗