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PubMed2002

Comparison of sitting versus prone position for stereotactic large-core breast biopsy in surgically proven lesions.

OBJECTIVE: Our purpose was to compare the two different body positions for stereotactic large-core breast biopsy with regard to sensitivity, specificity, and accuracy, as well as complication rate. SUBJECTS AND METHODS: Two hundred patients had large-core breast biopsy performed either in the prone (n = 100) or in the sitting (n = 100) position and subsequently underwent surgical resection. The histopathologic findings of large-core breast biopsy and surgery of all 200 patients were compared; sensitivity, specificity, and accuracy were calculated for both groups. Biopsy-associated complications were prospectively recorded for immediate and delayed events and for technical failures in both groups. RESULTS: Sensitivity (96%), specificity (100%), and accuracy (98%) were the same for both groups with two false-negative findings in each group. The two false-negative results in the sitting group were caused by vasovagal reactions, whereas those in the prone group were caused by technical failure and uncomfortable biopsy position. More statistically significant complications (seven vs four, p < 0.001) and vasovagal reactions (seven vs two, p < 0.0001) were seen in the sitting group. CONCLUSION: For performance of large-core breast biopsy, both the prone and sitting positions are reliable and accurate methods. However, vasovagal reactions that could potentially complicate biopsy were seen significantly more often in the sitting position.

Adult↗

PubMed1993

Stereotactically guided fractionated radiotherapy: technical aspects.

A system for high precision radiotherapy in the head and neck region has been developed. The components of the system are a head mask connected to a stereotactic frame, a localization unit that can be used during CT- and MR-imaging and a stereotactic target positioner. Conformal precision radiotherapy is planned with a new treatment planning system (Voxelplan-Heidelberg). Three different multi-leaf collimator systems are used. An evaluation of the precision and accuracy of the head fixation system, which was performed with a photogrammetry system, is presented.

Head↗

PubMed1993

Titanium Riechert head ring for MR stereotaxy. Technical note.

Magnetic Resonance has become the preferred neuro-imaging modality. To fully take advantage of the high anatomical resolution the Riechert stereotactic system was adapted for use in Magnetic Resonance Stereotaxy. The head ring which until recently was made of an aluminum alloy has been replaced by an unsegmented head ring of pure titanium without changing the dimensions and fixation mode. No significant misregistration due to eddy currents has been noticed. Minor distortion induced by the titanium head ring can be corrected mathematically. Thus the geometric information is limited only by the pixel resolution of the MR image.

Artifacts↗

PubMed1987

Interstitial brachytherapy of malignant brain tumors using computed tomography-guided stereotaxis and available imaging software: technical report.

The implantation of radioactive sources into malignant intraaxial brain tumors, interstitial brachytherapy, is a theoretically attractive treatment for these nearly uniformly fatal lesions. Optimal application of this treatment modality requires careful preoperative planning, computer-assisted dosimetry, and computed tomography-guided stereotactic implantation of the isotope-bearing catheters. A method is presented by which available computed tomographic imaging software can be used with a standard radiotherapy treatment planning computer and the Brown-Roberts-Wells stereotactic system for preoperative imaging, dosimetry planning, and brachytherapy catheter insertion. Dedicated computer facilities are not required, making this method available to any neurosurgeon with access to a current generation computed tomographic scanner.

Brachytherapy↗

PubMed2002

A four-year experience with a stereotactic computer in a small neurosurgical department.

BACKGROUND: A stereotactic computer with a mechanical, proprioceptive arm was acquired in 1996. The aim of this report is to review the 4-year experience with frameless, computer-aided stereotaxy in a small neurosurgical department. METHODS: From 1996 to 1999 the computer was used for 121 operations. The surgical files from these operations were either retrospectively or prospectively registered. Patient and computer data, type of surgery, complications and number of surgeons were noted. The versatility, benefits, and drawbacks of the stereotactic computer were evalued based on these findings. RESULTS: Seven surgeons performed a total of 121 computer-assisted operations. The procedures consisted of 63 stereotactic tissue samplings, 44 craniotomies, 7 abscess punctures and 3 insertions of intracerebral devices (shunts and microelectrodes). Technical complications were seen in 6 cases (4.8%), but this did not affect the surgical outcome. CONCLUSIONS: The stereotactic computer has enabled the department to broaden its spectrum of procedures. High precision surgery such as stereotactic biopsy has been possible without the use of a framebased system. The results indicate that even small neurosurgical units with a limited number of procedures can safely and successfully implement neuronavigation in daily routines.

Adolescent↗

PubMed1997

Infrared-based neuronavigation and cortical motor stimulation in the management of central-region tumors.

An infrared-based neuronavigation device (Surgical Microscope Navigator) integrating a pointer system with microscope guidance, is presented. We report our experience with this system in 17 patients undergoing surgery for space-occupying lesions of the central region. Cortical motor stimulation was additionally used in selected cases. The system was helpful in all operations by guiding craniotomy, corticotomy, or extent of tissue resection. Gross total tumor removal was possible in all patients but 1. Technical problems occurred in 1 case. Postoperative neurological worsening was found in 3 patients; this was reversible within a few weeks in 2 of them. In 9 cases, neuronavigation (combined with cortical stimulation, if necessary) probably prevented permanent neurological injury by exactly localizing tumors in the central area. It is concluded that neuronavigation (combined with motor cortex stimulation) may decrease neurological injury or neurosurgical invasiveness in lesions of the central region.

Astrocytoma↗

PubMed1990

Initial experience related to the use of the Cosman-Roberts-Wells stereotactic instrument. Technical note.

Initial experience with a new arc-radius design of stereotactic frame that interfaced with the existing components of the Brown-Roberts-Wells instrument is reported. Over a 6-month period, 32 procedures were performed on 23 males and nine female patients (mean age 32 years); these included 27 stereotactic biopsy procedures, two stereotactic implantations of cyst catheter reservoirs, two ventriculoscopic aspirations of third ventricular colloid cysts, and one stereotactic aspiration of a craniopharyngioma. In all cases successful targeting was achieved and verified by postoperative computerized tomography. There were no operation-related complications. This new frame offers rapid and accurate targeting and is a useful adjunct to the stereotactic armamentarium.

Adult↗

PubMed1995

Modifications of transnasal and transoral stereotactic procedures--technical notes.

Stereotactic transnasal and transoral procedures have been reported by different authors in the past. In this paper, several modifications of these methods are described. The modifications are: transnasal approach to the frontal skull base and suprasellar regions; and transoral approaches to the clivus, the petroclival junction, medial part of the cerebellopontine angle and the lateral mass of C-1. Eleven patients were operated on using these modifications. The procedures were for biopsy and brachytherapy. No complications resulted from the procedures.

Adolescent↗

PubMed1983

Stereotactic systems and procedures for depth electrode placement: technical aspects.

The authors describe the conversion of the Leksell spherical system to that of the orthogonal approach for depth electrode placement, by the addition of relatively simple devices to the main frame. These modifications have created the need for new instrumentation such as teleradiology with laser beam centering and the use of an all-purpose stereotactic chair. The main device used for the orthogonal approach is an instrument and electrode carrier moving on sliding side bars. This system can also take advantage of the newer imaging techniques, such as CT scanning, digital angiography and NMR, by the addition of computer markers which are interchangeable with the frame side bars.

Brain Mapping↗

PubMed1995

[Stereotaxic convergent irradiation with the gamma knife. A study of the possibilities for optimizing the dosage distribution].

PURPOSE: On April 1992, the first stereotactic radiosurgical procedure using the gamma knife was performed at the University Medical School Graz, Department of Neurosurgery. Accurate dose optimization is the foundation of a convenient and responsible utilization of this modality. But there are limits, because the final collimation is only achieved by 1 of the 4 special helm collimators. MATERIAL AND METHODS: The possibilities of dose optimization and its influence on the dose distributions were investigated and partly compared with results of film densitometry measurements. In detail, the technique, which uses the same isocenter, but different sized collimators was studied. The influence of these optimization techniques on the resulting dose distributions and the dose gradient at the edge of the treatment planning volume was analyzed. Also the visions for an effective dose optimization are discussed. RESULTS: With 2 shots of different diameters, located at the same target coordinates and different weighting of time any collimator size between the 4 mm and 18 mm can be achieved. Because of that, a combination of more than 2 collimators is not meaningful. With the combined shots the dose fall gradient was less than that of either of the single shots involved in the combination. CONCLUSIONS: With the available physical and technical possibilities only a limited, very time consuming optimization is practicable. The quality control of isodose distributions requires optimizations in hard- and software, that enable CT- or MRT-based 3-dimensional visualization and dose volume analysis.

Brain Neoplasms↗

PubMed2001

Localisation of the subthalamic nucleus using Radionics Image Fusion and Stereoplan combined with field potential recording. A technical note.

Subthalamic nucleus stimulation is an effective therapy for alleviating parkinsonian tremor, rigidity and bradykinesia. Although microelectrode recording is said to be essential for accurate targeting, this often prolongs the operation and the multiple recording tracts required may increase the incidence of complications, particularly haemorrhage. We describe a technique for implantation of deep brain electrodes in the subthalamic nucleus using MRI/CT fusion for anatomical localisation followed by bipolar recording of focal field potentials via the implanted stimulating electrode for neurophysiological confirmation of the stimulation site. The technique is effective, safe and requires much less time, and can be used as an alternative method to microelectrode recording.

Electric Stimulation Therapy↗

PubMed1989

Transcranial Doppler arteriography--a technical note.

Transcranial Doppler (TCD) evaluation of the intracranial vessels was performed in sixty-six patients, 51 of whom received conventional angiography either prior to or subsequent to the ultrasonic arteriogram. Of the 14 patients evaluated for arteriovenous malformations (AVMs), TCD indicated the existence of the AVM in 10 cases. Of those 10 cases, 9 correlated with angiography. Twenty-one patients with aneurysms were evaluated with TCD and only 2 were detected. Twenty-three patients suspected of having ischemic disease were evaluated with TCD, which indicated the presence of stenosis in 21 patients. Twenty of those patients received conventional angiography, with 18 demonstrating significant stenosis.

Blood Flow Velocity↗

PubMed1994

Stereotactic gamma-thalamotomy with a computerized brain atlas: technical case report.

Radiosurgical stereotactic thalamotomy was performed in a patient with parkinsonian tremor with a computerized stereotactic brain atlas, which was transformed to fit the patient's thin-sliced magnetic resonance image to select an optimal target in the nucleus ventralis intermedius of the thalamus. The patient's tremor and rigidity disappeared and have not appeared again for more than 1 year since the eighth postoperative month. A method for converting the presurgically planned stereotactic coordinates in the atlas coordinate system to the coordinates in the frame coordinate system is described.

Aged↗

PubMed1994

A simple technique for making a stereotactic localiser both CT and MRI compatible. Technical note.

Stereotactic neurosurgery requires the utmost precision. This can be achieved with modern imaging methods, provided special localisers are used which produce reference points for the calculation of stereotactic coordinates. Since not every substance can be visualised in every imaging modality, various localisers are normally used. These contain, for example, thin steel wires for CT or copper sulphate for MRI. By using a mixture of jopamidol and copper sulphate at a ratio of 1:1, it is possible to make the reference points of a localiser visible in both CT as well as in MRI. In this way, the entire stereotactic planning can be carried out using only one single localiser. This not only simplifies the procedure, it also reduces costs.

Copper↗

PubMedDate not supplied

[Stereotactic localization in medical imaging. Technical and methodologic aspects].

Stereotactic neurosurgery and stereotactic radiation therapy require the three-dimensional localization of lesions for biopsy or for treatment planning. The aim of this paper is the description of methods used in the different imaging modalities: x-ray teleradiography, digital subtracted angiography, computed tomography, and nuclear magnetic resonance imaging. The simple pin-target locating techniques are distinguished from those serving to the definition of volumes target necessary to treatment planning. Performances and difficulties of these techniques are emphasized. The specific methodology developed in Lille is described as an example. Organizational aspects and necessary quality controls for a good progress of the entire procedure, from imaging to treatment, are also discussed.

Angiography, Digital Subtraction↗

PubMed1995

Virtual image guided navigation in tumor surgery--technical innovation.

We present a new visualization system for image-guided stereotactic navigation in tumor surgery. The combination of frameless stereotactic localization technology with real-time video processing permits the visualization of medical imaging data as a video overlay during the actual surgical procedure. Virtual computer-generated anatomical structures are displayed intraoperatively in a semi-immersive head-up display. This results in surgical navigation assistance without limiting the judgement of the physician based on the continuous observation of the operating field. The case presented documents the potential of augmented reality visualization concepts in tumor surgery of the head.

Computer Simulation↗

PubMed1977

Surgery of the pituitary gland.

Increasing diagnostic sophistication among endocrinologists has continually expanded the horizon of surgical treatment of adenohypophyseal problems. This advancement in endocrinology has been paralleled by improvement in the technical sophistication of neurosurgeons which has resulted in an increasingly aggressive approach to these serious disorders. Neurosurgical treatment is clearly able to provide resolution of significant physical disorders with minimal sequelae. The apparent potential for transsphenoidal approaches to the sella turcica as described within this paper has intrigued a number of neurosurgeons throughout this century. Their continuing interest has carried this procedure to a secure position in the management of many of these complex problems. This paper describes the author's experience with 132 consecutive transsphenoidal hypophysectomies.

Acromegaly↗

PubMed1991

Surgical strategies and technical methodologies in optimal management of craniopharyngioma and masses affecting the third ventricular chamber.

Management of craniopharyngiomas and masses affecting the third ventricular chamber represents one of the most challenging problems confronting contemporary neurological surgeons. Given the devastating sequelae of surgical complications involved in approaches to the deep cerebral midline, surgical management requires a combination of sophisticated imaging, diagnostic pathology and surgical technique including ventricular microsurgery and stereotaxy and its attendant refinements. Surgical and non-surgical management is based upon the structural presentation of these masses as defined by detailed imaging studies. Operative objectives include histological definition, maximally feasible excision, cerebral spinal fluid diversion and relief of neurologic deficits created by masses affecting the third ventricular chamber.

Cerebral Ventricle Neoplasms↗