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Results for “Neuronavigation”

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PubMed2006

[Minimally invasive surgery of the pituitary and the sellar region].

INTRODUCTION: New minimal invasive neurosurgical approaches for the treatment of diseases in the sellar and perisellar regions (superciliary and paraseptal approach, perioperative ACTH measurements, application of endoscopes and neuronavigation) were introduced by the author. The modified surgical techniques were applied by the author successfully in the treatment of more than 1000 cases, of which the data of 746 patients were analysed and the results are presented. METHODS AND RESULTS: The results of the clinical studies concerning superciliary and paraseptal approaches were as follows: length of the operations and, loss of blood were decreased, the patients needed shorter anesthesia and the treatment cost became lower. The approaches were performed without hair cutting with excellent cosmetic results leading to easier resocialisation of the patients. In the group of the patients operated on through the superciliary approach postoperative vasospasm developed in significantly lower rate, the number of days spent in the intensive care unit decreased and the rate of patients on discharge in good clinical condition were higher. The study on perioperative plasma ACTH simultaneous measurements with rapid and standard methods revealed first in the literature that, during anaesthesia in patients with ACTH producing adenoma the plasma ACTH level changed individually. There was no difference between arterial and venous plasma ACTH concentration in the same patient and the ACTH concentration in the bleedings from the peripituitary bony structures are individually variable, representing the network of the venous outflow of the pituitary. The decrease in the plasma ACTH concentrations in the peripheral venous samples two hours after operation and next morning proved the radical removal of the adenoma. The differences between concentrations in the left and right sides indicate the intrapituitary lateralization of the adenoma. The study on the usefulness of neuroendoscopy and neuronavigation in the author's hand revealed the advantages and disadvantages of these new neurosurgical instruments. CONCLUSIONS: With the advent of the minimal invasive methods in surgery of the pituitary and the sellar region the mortality end the morbidity of the operations decreased.

Adenoma↗

PubMed1995

[A surgically treated case of ventrally exophytic pontine glioma].

A surgically treated case of ventrally exophytic pontine glioma is reported. A 49-year-old woman, complaining of dysarthria, dysphagia and gait disturbance, was admitted to our department. Her past history included bronchial asthma. Plain skull x-p and tomography revealed destruction of the dorsum sellae and upper clivus. CT demonstrated an enhanced oval mass at the ventral side of the upper brainstem. The mass was severely compressing the brainstem dorsally. MRI revealed a low-intensity band between the tumor and the brainstem. Dynamic MRI demonstrated a pattern of rapid increasing and slow reduction. Cerebral angiogram demonstrated a paradoxical sign that pontine branches were located anterior to the basilar artery. The finding demonstrated that the tumor was an intraaxial mass. The first operation was performed by the orbitofrontomalar approach. On the trans-sylvian route, the tumor was removed partially with CUSA and neuronavigation system. Its histology was astrocytoma grade III. Radiation therapy was added. The patient's symptoms aggravated again. On the second operation, the transtemporal route with tentorial resection was chosen. Under a wide visual field, intracapsular subtotal resection of the tumor was performed. Interferon therapy was added. She was discharged to her home with no neurological deficits. Ventrally exophytic pontine glioma is very rare. Low-intensity band of MRI, a sign of extraaxial mass, was visualised in our case. On the other hand, cerebral angiogram demonstrated a paradoxical sign. This sign suggested that the tumor originated from the brainstem. With update skull base surgery and neuronavigation system, surgical therapy of ventrally exophytic pontine glioma is safe and effective.

Brain Neoplasms↗

PubMed1997

Clinical introduction of an adjustable rigid instrument holder for frameless stereotactic interventions.

Interactive image guidance is now in routine use for open neurosurgical procedures and has demonstrated patient benefits. However, freehand interactive guidance is not an appropriate replacement for the traditional frame-based stereotactic procedures of biopsy, electrode placement, and functional lesioning. These point-based procedures require precise target localization and direct instrument guidance to avoid collateral brain injury. To perform true frameless stereotactic procedures requires a guide that is also adjustable for positioning, lockable, and adaptable to multiple instruments. We describe such a device, which is employed for the guidance of biopsy needles, shunts, electrodes, and endoscopes during neuronavigation. The method of frameless stereotactic biopsy retrieval with an infrared-based neuronavigation system is described, clinical results are given, and further areas of application discussed.

Adult↗

PubMed2003

Intraoperative imaging--MRI.

Neuronavigation has become a standard technique in many neurosurgical procedures where its use allow better positioning of the craniotomy flap, precise targeting of lesions, and better anatomical orientation. However, the imaging used in such procedures is acquired preoperatively and thus, cannot project the dynamic changes that occur during surgery and result in many cases in significant brain shift and decreased accuracy. Recent technological developments have yielded a variety of MRI machines that can be used intraoperatively and provide the surgeon with updated images, integrated navigation capabilities, full compensation for brain shifts, and the ability to assess the extent of resection of the lesion. The concepts behind such technologies vary from one manufacture to another resulting in systems that vary in complexity, ease of use, spatial demands, and cost. In this chapter we review our experience with two intraoperative MRI systems used in a variety of neurosurgical procedures: the GE Signa SP System and the Odin PoleStar System.

Biopsy↗

PubMed2004

[Preoperative imaging as the basis for image-guided neurosurgery].

With the progressive development of soft- and hardware, the acceptance of image-guided neurosurgery has increased dramatically. Additional image data are required to analyze the nature and the dimensions of pathological processes and the surrounding tissue. In this context, fMRI, SPECT, PET, as well as special modalities of CT and MR imaging, are routinely used. Secondary post-processing options are used to detect intracerebral lesions as well as adjacent functional eloquent regions in the parenchymatous organ pre- and intraoperatively. The integration of different image information guarantees the precise planning and realization of surgical maneuvers. The segmentation of interesting structures and risk structures, as well as their implementation in the neuronavigation systems, help to avoid additional intraoperative traumatization and offer a higher level of safety and precision. In this article the value and limitations of presurgical imaging will be discussed.

Brain↗

PubMed2003

Three-dimensional true FISP for high-resolution imaging of the whole brain.

While high-resolution T1-weighted sequences, such as three-dimensional magnetization-prepared rapid gradient-echo imaging, are widely available, there is a lack of an equivalent fast high-resolution sequence providing T2 contrast. Using fast high-performance gradient systems we show the feasibility of three-dimensional true fast imaging with steady-state precession (FISP) to fill this gap. We applied a three-dimensional true-FISP protocol with voxel sizes down to 0.5 x 0.5 x 0.5 mm and acquisition times of approximately 8 min on a 1.5-T Sonata (Siemens, Erlangen, Germany) magnetic resonance scanner. The sequence was included into routine brain imaging protocols for patients with cerebrospinal-fluid-related intracranial pathology. Images from 20 patients and 20 healthy volunteers were evaluated by two neuroradiologists with respect to diagnostic image quality and artifacts. All true-FISP scans showed excellent imaging quality free of artifacts in patients and volunteers. They were valuable for the assessment of anatomical and pathologic aspects of the included patients. High-resolution true-FISP imaging is a valuable adjunct for the exploration and neuronavigation of intracranial pathologies especially if cerebrospinal fluid is involved.

Adult↗

PubMed2004

Functional magnetic resonance imaging for neurosurgical planning in neurooncology.

Functional magnetic resonance imaging (fMRI) is a non-invasive technique that is widely available and can be used to determine the spatial relationships between tumor tissue and eloquent brain areas. Within certain limits, this functional information can be applied in the field of neurosurgery as a pre-operative mapping tool to minimize damage to eloquent brain areas. In this article, we review the literature on the use of fMRI for neurosurgical planning. The issues addressed are: (1) stimulation paradigms, (2) the influence of tumors on the blood oxygenation level-dependent (BOLD) signal, (3) post-processing the fMRI time course, (4) integration of fMRI results into neuronavigation systems, (5) the accuracy of fMRI and (6) fMRI compared to intra-operative mapping (IOM).

Adult↗

PubMed2003

Endo-neuro-sonography: first clinical series (52 cases).

OBJECTIVE: A sono catheter for transendoscopic imaging was applied in neurosurgery for the first time in 52 patients with a broad variety of lesions. METHODS: A transendoscopic sono catheter (Aloka Deutschland GmbH, Düsseldorf, Germany) with a diameter of 1.9 mm (6F) was used and introduced into the working canal of an endoscope. The image produced by the probe is a 360 degrees scan ("brain radar") displayed on a monitor, on which some parameters can be varied to get the best view of the different anatomical structures. RESULTS: In 39 patients intraoperative imaging was the main reason for investigation and in 13 patients neuronavigation was the focus of interest. In 18 cases of tumor resection control targeting a visualized remnant was necessary. There are limitations and artifacts, which should reveal themselves in laboratory and clinical experience. CONCLUSION: In this small series, endo-neuro-sonography proved to make neuroendoscopy safer and easier by online and real-time imaging with high resolution.

Adolescent↗

PubMed2004

Neuroendoscopic surgery of intracranial cysts in adults.

OBJECTS: The purpose of this study was to describe the indications, surgical techniques and postoperative outcome of neuroendoscopic interventions in a heterogeneous group of intracranial cystic pathologies. PATIENTS AND METHODS: Between 1992 and 2003, 127 patients with symptomatic intracranial cysts and cystic tumours underwent neuroendoscopic treatment in our department. In 22 patients indication for surgery was colloid cysts, in 9 patients pineal cysts and in 3 patients cavum vergae cysts. Twelve arachnoid cysts, 10 cystic craniopharyngiomas, 2 Rathke's cleft cysts and 69 malignant cystic tumours were operated on. The patients' mean age was 45 years and their clinical presentations varied from typical signs of increased intracranial pressure to focal neurological deficits. RESULTS: One hundred and twenty-seven patients with intracerebral cystic space-occupying lesions were operated on using stereotactic frameless or frame-based endoscopic techniques. There was no operative mortality. The operative morbidity was 3.1% including 1 memory deficit due to fornix injury, 1 hemiparesis due to postoperative haematoma after lesion biopsy, 1 aseptic meningitis and 1 subdural fluid collection. CONCLUSIONS: Endoscopic interventions enable neurosurgeons to manage intracranial cystic lesions. Via the same approach, the obstructed CSF pathways may be restored and consequently the increased intracranial pressure diminishes. With the aid of stereotactic guidance or a neuronavigation system, access to the lesion can be gained rapidly and with high accuracy.

Adult↗

PubMed2004

Use of a compact intraoperative low-field magnetic imager in pediatric neurosurgery.

OBJECT: The majority of investigations on the utility of and indications for intraoperative magnetic resonance imaging (iMRI) have been in adult patients. We report our initial experience utilizing low-field iMRI in pediatric patients. METHODS: We performed 21 procedures on 20 patients aged 2 months to 18 years (mean 8.9 years) utilizing the PoleStar -10 iMRI system. The procedures included 15 craniotomies, 2 shunts, and 1 each of the following surgeries: transsphenoidal, craniotomy/transsphenoidal, cranioplasty, and endoscopic biopsy and fenestration. Treated lesions included low-grade astrocytoma (5), craniopharyngioma (3), cortical dysplasia (3), hydrocephalus (2), and others (8). The number of scans ranged from 2 to 5 with a mean of 3.2. Intraoperative imaging and navigation provided valuable information on the extent of resection and catheter placement. In eight procedures it influenced the surgical strategy. No untoward events attributable to the system occurred. CONCLUSIONS: The low-field PoleStar -10 iMRI system can safely assist pediatric neurosurgeons treating a variety of diseases. In addition to neuronavigation it provides information on extent of resection, real-time guided catheter placement, and avoidance of complications.

Adolescent↗

PubMed2004

Robot-assisted navigated endoscopic ventriculostomy: implementation of a new technology and first clinical results.

BACKGROUND: Important landmarks in the evolution of advanced neurosurgical techniques during the past decades include microneurosurgery, neuro-endoscopy and its minimally invasive nature, as well as neuronavigation and advanced intra-operative imaging. With conventional neuroendoscopic techniques, e.g. free-hand endoscopy or the use of mechanical or pneumatic holding devices, a definitive and controlled movement of the endoscope within the brain does depend on the experience and manual skill of the individual neurosurgeon. Therefore, the development of robotic systems to assist surgeons in performing complex neurosurgical procedures is a growing field of interest. METHOD: With the precision robot "Evolution 1" (U.R.S. Universal Robot Systems, Schwerin, Germany) a new neurosurgical tool has just become available for the precise steering of instruments within the cranium. After preclinical anatomical as well as precision studies the system was used for robot-assisted navigated endoscopic third ventriculostomies in six patients with hydrocephalus related to aqueductal stenosis. FINDINGS: All robot-assisted navigated endoscopic procedures were successfully completed. The time for the registration procedure and setup of the robot decreased from 60 min. for the first procedure down to 30 min. The time for the surgical part of the neuro-endoscopic procedure itself ranged from 17 to 35 min. During all procedures no system-related complications occurred. INTERPRETATION: The use of robotic technology for neuro-endoscopic third ventriculostomies is a major step towards the controlled movement of the neuro-endoscope within the cranium. The start up procedure and calibration of the robot is still time consuming, but the real operation time is comparable to free hand neuro-endoscopy. The steering of the endoscope is facilitated and the precision of the endoscopic movements is noteworthy.

Adolescent↗

PubMed2005

Intra-operative 3D ultrasound in neurosurgery.

In recent years there has been a considerable improvement in the quality of ultrasound (US) imaging. The integration of 3D US with neuronavigation technology has created an efficient and inexpensive tool for intra-operative imaging in neurosurgery. In this review we present the technological background and an overview of the wide range of different applications. The technology has so far mostly been applied to improve surgery of tumours in brain tissue, but it has also been found to be useful in other procedures such as operations for cavernous haemangiomas, skull base tumours, syringomyelia, medulla tumours, aneurysms, AVMs and endoscopy guidance.

Brain↗

PubMed2004

Endoscope-assisted microsurgery for tumors of the septum pellucidum: surgical considerations and benefits of the method in the treatment of four serial cases.

Neoplasms that primarily originate from the septum pellucidum are extremely rare. Generally the septum pellucidum is involved in direct extension of tumors that arise from the neighboring structures, principally the corpus callosum. Endoscope-assisted techniques form a useful adjunct to common microsurgical procedures to completely remove intraventricular lesions. There are two main advantages of endoscope-assisted surgery over common microsurgical techniques: reduction of superficial brain retraction with less iatrogenic trauma to the neighboring structures and inspection of hidden corners depict simultaneously anatomical details which are not precisely visible in the zoomed and thus light-reduced beam of the microscope. Four patients with septum pellucidum tumors underwent surgery by a transcallosal approach. In all four patients the endoscope-assisted microsurgery technique was used to remove the tumor. In one of the four patients neuronavigation was additionally used for guidance. Complete tumor excision was achieved in all patients. The histological findings showed pilocytic astrocytoma in two cases, one subependymoma and one neurocytoma, respectively. There were no postoperative complications. Endoscope-assisted microsurgery provides maximum efficiency to remove the septum pellucidum tumors with minimum invasiveness.

Adult↗

PubMed2006

[Surgical intervention in patients with malignant glioma].

Glial tumors occur at an incidence from 2 to 10/ 100.000 (Japan vs. Sweden) and building up to 50 % of all patients suffering from brain tumors. 50 % of those are again malignant gliomas Grade III and Grade IV. Despite all therapeutic approaches the median survival for glioblastomas is 15 months and for anaplastic gliomas Grade III 30 months. After diagnosis, preferably by MRI, a neurosurgical procedure is performed under microsurgical guidelines mostly by means of neuronavigation and intraoperative guidance. Depending on the preoperative diagnosis and localisation of the pathologic lesion an open craniotomy or a stereotactic biopsy is performed. This allows the histological verification and decompression and cytoreduction. A gros total safe removal preserving neurological function is the most important goal of surgery. Tumor removal in eloquent areas such as speech area is performed under local anesthesia as an awake operation. Age, Karnofsky performance status, histology as well as radical removal have a significant influence on overall survival. Adjuvant radiotherapy and chemotherapy with Temozolemide have further improved the outcome significantly. The 2-year survival has reached 28 % in most recent studies. Further experimental therapies in controlled trials, such as intratumoral convection-enhanced instillation of immunotoxins and radiopeptids, photodynamic therapy and direct instillation of new formulations of chemotherapeutic drugs (e. g. nanoparticles) are promising new approaches. New developments in the treatment of patients harboring malignant brain tumors allow an individual neurooncological treatment concept to be established to enhance overall survival and quality of life.

Brain↗

PubMed2006

Transcranial magnetic stimulation for the treatment of tinnitus: a new coil positioning method and first results.

Auditory phantom perceptions are associated with hyperactivity of the central auditory system. Neuronavigation guided repetitive transcranial magnetic stimulation (rTMS) of the area of increased activity was demonstrated to reduce tinnitus perception. The study aimed at developing an easy applicable standard procedure for transcranial magnetic stimulation of the primary auditory cortex and to investigate this coil positioning strategy for the treatment of chronic tinnitus in clinical practice. The left gyrus of Heschl was targeted in 25 healthy subjects using a frameless stereotactical system. Based on individual scalp coordinates of the coil, a positioning strategy with reference to the 10--20-EEG system was developed. Using this coil positioning approach we started an open treatment trial. 28 patients with chronic tinnitus received 10 sessions of rTMS (intensity 110% of motor threshold, 1 Hz, 2000 Stimuli/day). Being within a range of about 20 mm diameter, the scalp coordinates for stimulating the primary auditory cortex allowed to determine a standard procedure for coil positioning. Clinical validation of this coil positioning method resulted in a significant improvement of tinnitus complaints (p<0.001). The newly developed coil positioning strategy may have the potential to offer a more easy-to-use stimulation approach for treating chronic tinnitus as compared with highly sophisticated, imaging guided treatment methods.

Adult↗

PubMed2006

Cerebral edema attenuated inversion recovery MR sequence in low magnetic field: a feasibility study.

RATIONALE AND OBJECTIVES: Minimally invasive neurosurgery requires methods to specify surgical boundaries of target tissue, such as brain tumors. This study investigated technical possibilities and clinical usefulness of adapting edema attenuated inversion recovery (EDAIR) pulse sequences to suppress magnetic resonance signal from cerebral edema in brain tumor patients. MATERIALS AND METHODS: A resistive 0.23-T magnetic resonance scanner with magnitude-encoded inversion recovery sequences was used. Twenty-eight separate scanning tests in 25 neurosurgical brain tumor patients were performed on the day before surgery. An inversion recovery sequence with several inversion times between 150 and 2,200 ms was tested. The same sequences were also used intraoperatively and postoperatively. RESULTS: T(1) relaxation time of brain edema varied from case to case. An inversion recovery sequence with an inversion time of 400-800 milliseconds attenuated brain edema and seemed to help in demarcating gross brain tumor for surgical resection. These features were helpful for the evaluation of resectable tumor tissue particularly using neuronavigation techniques. CONCLUSIONS: According to these preliminary findings, inversion recovery sequences supplement other imaging modalities and assist neurosurgeons in evaluating different surgical trajectories and in estimating brain tumor volume before craniotomy.

Adolescent↗

PubMed2005

Navigated dorsolateral suboccipital transcondylar (NADOSTA) approach for treatment of hypoglossal schwannoma. Case report and review of the literature.

Hypoglossal schwannoma is a rare skull base neoplasm, which lies in the midst of extremely complex anatomical structures. We report a 39-year-old man who presented with a history of right glossal hemiatrophy, dysesthesia and weakness of the left extremities. These symptoms were caused by a unilateral hypoglossal schwannoma located at the cranial base. This lesion was exposed through a dorsolateral suboccipital transcondylar approach, which was navigated with the frameless stereotaxy (NADOSTA). We also describe the epidemiology, symptomatology and the diagnosis of hypoglossal schwannoma as well as literature review of the operative approach. By introducing this minimally invasive dorsal surgical approach with neuronavigation in treating hypoglossal schwannoma, we believe that safe exposure and complete tumor resection can be achieved with minimal rate of morbidity.

Adult↗

PubMed2006

Image-guided placement of ventricular shunt catheter.

The position of the ventricular shunt catheter is by far most important factor in the long-term patency of a cerebrospinal fluid shunt. However, standard technique, which relies on surface anatomic landmarks and the surgeon's sense of spatial orientation, is not consistently accurate in the positioning the ventricular shunt catheter. Image guidance provides not only a three-dimensional reconstruction of the ventricular system, but also a real-time virtual trajectory for the catheterization. The authors, using a neuronavigation system, describe the ideal trajectory and target for accurate placement of a ventricular shunt catheter. Seventeen consecutive trials of image-guided placement of the ventricular shunt catheter resulted in excellent positioning of the catheter, within the free cerebrospinal fluid space just anterior to the foramen of Monro. This positioning was accurate in each case, even if the ventricles were distorted or shifted.

Adult↗