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Results for “Neuronavigation”

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At least 361 records · Page 20Linked to original sources

PubMed2005

Traumatic C6-7 subluxation associated with C-7 fracture treated with a pedicle screw system under navigation guidance--case report.

A 51-year-old female presented with traumatic C6-7 subluxation associated with C-7 fracture due to an automobile accident. She underwent pedicle screw fixation at C-6, C-7, and T-1 for stabilization of the spinal column. A neuronavigation system was used to obtain accurate placement of the pedicle screws. The patient recovered well without further neurological compromise. Postoperative cervical radiography showed reasonable restoration of the vertebral column without delayed kyphotic deformity.

Bone Screws↗

PubMed2005

Design, implementation and accuracy of a prototype for medical augmented reality.

OBJECTIVE: This paper is focused on prototype development and accuracy evaluation of a medical Augmented Reality (AR) system. The accuracy of such a system is of critical importance for medical use, and is hence considered in detail. We analyze the individual error contributions and the system accuracy of the prototype. MATERIALS AND METHODS: A passive articulated arm is used to track a calibrated end-effector-mounted video camera. The live video view is superimposed in real time with the synchronized graphical view of CT-derived segmented object(s) of interest within a phantom skull. The AR accuracy mostly depends on the accuracy of the tracking technology, the registration procedure, the camera calibration, and the image scanning device (e.g., a CT or MRI scanner). RESULTS: The accuracy of the Microscribe arm was measured to be 0.87 mm. After mounting the camera on the tracking device, the AR accuracy was measured to be 2.74 mm on average (standard deviation = 0.81 mm). After using data from a 2-mm-thick CT scan, the AR error remained essentially the same at an average of 2.75 mm (standard deviation = 1.19 mm). CONCLUSIONS: For neurosurgery, the acceptable error is approximately 2-3 mm, and our prototype approaches these accuracy requirements. The accuracy could be increased with a higher-fidelity tracking system and improved calibration and object registration. The design and methods of this prototype device can be extrapolated to current medical robotics (due to the kinematic similarity) and neuronavigation systems.

Humans↗

PubMed2003

Coregistered intraoperative ultrasonography in resection of malignant glioma.

OBJECT: The authors present their experience with coregistration of preoperative imaging data to intraoperative ultrasonography in the resection of high-grade gliomas, focusing on methodology and clinical observation. METHODS: Images were obtained preoperatively and coregistered to intraoperative hand-held ultrasound images by merging the respective imaging coordinate systems. After patient registration and imaging calibration, the authors computed the location on the magnetic resonance (MR) space of each pixel on an ultrasound image acquired in the operating room. The data were retrospectively reviewed in 11 patients with high-grade gliomas who underwent ultrasonography-assisted resection at our institution between June 2000 and December 2002. Satisfactory coregistration of intraoperative ultrasound and preoperative MR images was accomplished in all cases. Ultrasound and MR image data were closely congruent. Preoperative setup and intraoperative use of the system were unencumbering. CONCLUSIONS: Based on these preliminary results, intraoperative ultrasonography is an attractive neuronavigational alternative, by which a less expensive and constraining imaging technique is used to acquire updated information. Optimal intraoperative guidance can be provided by the integration of this with other imaging studies.

Adult↗

PubMed2003

Preoperative magnetic source imaging for brain tumor surgery: a quantitative comparison with intraoperative sensory and motor mapping.

OBJECT: The aim of this study was to compare quantitatively the methods of preoperative magnetic source (MS) imaging and intraoperative electrophysiological cortical mapping (ECM) in the localization of sensorimotor cortex in patients with intraaxial brain tumors. METHODS: Preoperative magnetoencephalography (MEG) was performed while patients received painless tactile somatosensory stimulation of the lip, hand, and foot. The early somatosensory evoked field was modeled using a single equivalent current dipole approach to estimate the spatial source of the response. Three-dimensional magnetic resonance image volume data sets with fiducials were coregistered with the MEG recordings to form the MS image. These individualized functional brain maps were integrated into a neuronavigation system. Intraoperative mapping of somatosensory and/or motor cortex was performed and sites were compared. In two subgroups of patients we compared intraoperative somatosensory and motor stimulation sites with MS imaging-based somatosensory localizations. Mediolateral projection of the MS imaging source localizations to the cortical surface reduced systematic intermodality discrepancies. The distance between two corresponding points determined using MS imaging and ECM was 12.5 +/- 1.3 mm for somatosensory-somatosensory and 19 +/- 1.3 mm for somatosensory-motor comparisons. The observed 6.5 mm increase in site separation was systematically demonstrated in the anteroposterior direction, as expected from actual anatomy. In fact, intraoperative sites at which stimulation evoked the same patient response exhibited a spatial variation of 10.7 +/- 0.7 mm. CONCLUSIONS: Preoperative MS imaging and intraoperative ECM show a favorable degree of quantitative correlation. Thus, MS imaging can be considered a valuable and accurate planning adjunct in the treatment of patients with intraaxial brain tumors.

Adolescent↗

PubMed2005

Spontaneous motor cortex encephalocele presenting with simple partial seizures and progressive hemiparesis. Case report and review of the literature.

Several cases of congenital or acquired temporal encephaloceles have been reported in the literature as the causative mechanism of simple and/or complex partial seizures. In this report the authors describe a rare case of spontaneous parietal encephalocele presenting with simple partial seizures and progressively increasing contralateral upper-extremity motor deficit. The unusual anatomical location of an encephalocele associated with seizures and the delayed seizure onset represent distinctive characteristics in this case. Preoperative imaging included surface electroencephalography, computerized tomography, and brain magnetic resonance imaging. Frameless neuronavigation and intraoperative cortical mapping were used to aid resection of the encephalocele, and the dural and bone defects were reconstructed. The surgical outcome in this case was excellent, and the patient has remained seizure free. The pertinent literature is reviewed in this report.

Disease Progression↗

PubMed2002

Preoperative magnetic source imaging for brain tumor surgery: a quantitative comparison with intraoperative sensory and motor mapping.

Adolescent↗

PubMed2002

Radiosurgery for residual or recurrent nonfunctioning pituitary adenoma.

OBJECT: Nonfunctioning pituitary adenomas comprise approximately 30% of all pituitary tumors. The purpose of this retrospective study is to evaluate the efficacy and role of gamma knife radiosurgery (GKS) in the management of residual or recurrent nonfunctioning pituitary adenomas. METHODS: A review was conducted of the data obtained in 42 patients who underwent adjuvant GKS at the University of Pittsburgh between 1987 and 2001. Prior treatments included transsphenoidal resection, craniotomy and resection, or conventional radiotherapy. Endocrinological, ophthalmological, and radiological responses were evaluated. The duration of follow-up review varied from 6 to 102 months (mean 31.2 months). Fifteen patients were observed for more than 40 months. The mean radiation dose to the tumor margin was 16 Gy. Conformal radiosurgery planning was used to restrict the dose to the optic nerve and chiasm. Tumor control after GKS was achieved in 100% of patients with microadenomas and 97% of patients with macroadenomas. Gamma knife radiosurgery was equally effective in controlling adenomas with cavernous sinus invasion and suprasellar extension. No patient developed a new endocrinological deficiency following GKS. One patient's tumor enlarged with an associated decline in visual function. Another patient experienced a deterioration of visual fields despite a decrease in tumor size. CONCLUSIONS: Gamma knife radiosurgery can achieve tumor control in virtually all residual or recurrent nonfunctioning pituitary adenomas. Dose sparing facilitates tumor management even when the adenoma is close to the optic apparatus or invades the cavernous sinus.

Adenoma↗

PubMed2005

Multimodal metabolic imaging of cerebral gliomas: positron emission tomography with [18F]fluoroethyl-L-tyrosine and magnetic resonance spectroscopy.

OBJECT: The purpose of this study was to determine the predictive value of [18F]fluoroethyl-L-tyrosine (FET)-positron emission tomography (PET) and magnetic resonance (MR) spectroscopy for tumor diagnosis in patients with suspected gliomas. METHODS: Both FET-PET and MR spectroscopy analyses were performed in 50 consecutive patients with newly diagnosed intracerebral lesions supposed to be diffuse gliomas on contrast-enhanced MR imaging. Lesion/brain ratios of FET uptake greater than 1.6 were considered positive, that is, indicative of tumor. Results of MR spectroscopy were considered positive when N-acetylaspartate (NAA) was decreased in conjunction with an absolute increase of choline (Cho) and an NAA/Cho ratio of 0.7 or less. An FET lesion/brain ratio, an NAA/Cho ratio, and signal abnormalities on MR images were compared with histological findings in neuronavigated biopsy specimens. The FET lesion/brain ratio and the NAA/Cho ratio were identified as significant independent predictors for the histological identification of tumor tissue. The accuracy in distinguishing neoplastic from nonneoplastic tissue could be increased from 68% with the use of MR imaging alone to 97% with MR imaging in conjunction with FET-PET and MR spectroscopy. Sensitivity and specificity for tumor detection were 100 and 81% for MR spectroscopy and 88 and 88% for FET-PET, respectively. Results of histological studies did not reveal tumor tissue in any of the lesions that were negative on FET-PET and MR spectroscopy. In contrast, a tumor diagnosis was made in 97% of the lesions that were positive with both methods. CONCLUSIONS: In patients with intracerebral lesions supposed to be diffuse gliomas on MR imaging, FET-PET and MR spectroscopy analyses markedly improved the diagnostic efficacy of targeted biopsies.

Adolescent↗

PubMed2005

Comparison of the reliability of brain lesion localization when using traditional and stereotactic image-guided techniques: a prospective study.

OBJECT: Accurate localization of brain lesions is of utmost importance. Traditional methods of localization that involve the use of neuroimaging and surface anatomy have been replaced in certain cases by using frameless stereotactic neuronavigational systems. Even though these systems have been found to be accurate, no studies have been conducted to investigate whether the systems provide improved localization accuracy compared with traditional methods. METHODS: Twenty-two patients undergoing image-guided surgery with the aid of the Stealth Neuro-Station were prospectively enrolled in this study. All patients underwent standard magnetic resonance or computerized tomography imaging, as well as special Stealth-sequenced imaging acquired using scalp fiducial markers. Traditional and Stealth estimates of the surface projection of lesions were determined, digitally photographed, and later compared. The mean (+/- standard deviation) error associated with traditional localization of lesions was 1.1 +/- 0.7 cm in the mediolateral plane and 1.3 +/- 1.1 cm in the anteroposterior plane. This error was not significantly affected by the size or location of the lesion. CONCLUSIONS: Findings of this study indicate that the conventional localization technique used to demarcate brain cortical and subcortical lesions has an error of approximately 1 to 1.5 cm in both the mediolateral and anteroposterior directions. This error can be reduced by judicious use of image-guided techniques.

Brain Diseases↗

PubMed2006

Intraoperative ventricular puncture during supraorbital craniotomy via an eyebrow incision. Technical note.

The authors determined the landmarks and coordinates for intraoperative ventricular puncture directly from the supraorbital craniotomy opening via an eyebrow incision. Fifty magnetic resonance (MR) imaging studies were obtained from patients with no pathological cerebral characteristics or ventricular distortion. The cerebral entry point of the ventriculostomy was located directly under the key bur hole (just behind the zygomatic process of the frontal bone) at the base of the frontal lobe because it represents a stable, reliable point that can be used as the bur hole during supraorbital craniotomy via an eyebrow incision. From this point, the coordinates for lateral ventricular puncture were determined using MR imaging studies and neuronavigational software. The cerebral entry point of the ventriculostomy was situated directly under the key bur hole at the base of the frontal lobe. The catheter was directed at a 45 degrees angle to the midline and a 20 degrees angle up from an imaginary line parallel to the orbitomeatal line. The catheter will usually be inserted into the ventricle at a point 5 cm deep to the cortex and may be inserted as deep as 6.5 cm. Using this technique, the frontal horn of the lateral ventricle can be easily tapped. The landmark required for this technique is readily available in all patients.

Catheterization↗

PubMed2002

[Integration of metabolic data by positron emission tomography in image-guided neurosurgical interventions].

The potential of positron emission tomography (PET) to investigate accurately in vivo pathophysiology has opened new perspectives for the management of neurological disorders, especially brain tumors. Integration of PET in the management of brain tumors represents a unique way to provide metabolic and functional information that can be used for diagnosis, guidance of therapies, and treatment monitoring. We have developed a stereotactic method allowing the routine integration of PET images in neurosurgical procedures with a high precision. Our ten year experience with the use of PET in stereotactic conditions for neurosurgical guidance, indicates that PET integration in image-guide neurosurgical approaches, including [1] stereotactic biopsy, [2] neuronavigation and [3] radiosurgery with Leksell Gamma Knife, is feasible and worthwhile, in that it provides complementary information that contribute to the optimization of the neurosurgical treatment of brain tumors.

Biopsy↗

PubMed2003

Neurosurgical stereomorphometry in vivo--method description and error measurement.

Rules of geometry and stereomorphometry are often applied to narrow and deep neurosurgical approaches. Methods of research are based on the direct cadaver measurements, radiological analysis and intraoperative measurements. Newly developed devices allow direct morphometry to be performed in vivo, during the operation. We describe the use of the neuronavigation system Stealth Station by Medtronic for such stereomorphometric measurements and evaluate the precision of the described method.

Humans↗

PubMedDate not supplied

Post-processing of digital images.

Post-processing of bi- and three-dimensional images plays a major role for clinicians and surgeons in both diagnosis and therapy. The new spiral (single and multislice) CT and MRI machines have allowed better quality of images. With the associated development of hardware and software, post-processing has become indispensable in many radiologic applications in order to address precise clinical questions. In particular, in CT the acquisition technique is fundamental and should be targeted and optimized to obtain good image reconstruction. Multiplanar reconstructions ensure simple, immediate display of sections along different planes. Three-dimensional reconstructions include numerous procedures: multiplanar techniques as maximum intensity projections (MIP); surface rendering techniques as the Shaded Surface Display (SSD); volume techniques as the Volume Rendering Technique; techniques of virtual endoscopy. In surgery computer-aided techniques as the neuronavigator, which with information provided by neuroimaging helps the neurosurgeon in simulating and performing the operation, are extremely interesting.

Image Interpretation, Computer-Assisted↗

PubMed2004

[Minimally invasive surgical techniques in the treatment of pituitary and peripituitary tumors: experience with the paraseptal approach].

INTRODUCTION: The direct endonasal, paraseptal approach, performed with the aid of an operating microscope, for removal of pituitary and peripituitary tumors has the potential advantage over the traditional sublabial, transseptal routes of minimizing postoperative rhinological complications, yet maintaining a high degree of efficacy and safety. Combination of this approach with the endoscope or neuronavigation may improve the effectiveness of the operation. METHODS AND RESULTS: Between June, 2000 and June, 2003 two hundred and seventeen patients underwent 221 paraseptal operations for tumor removal at the National Institute of Neurosurgery, Budapest. To asses the effectiveness of this procedure, duration of the operation, tumor remission rates and surgical complications as well as postoperative complaints of patients were reviewed. Surgical remission rates for pituitary adenomas were as follows: 94% for microadenomas, 67% for macroadenomas and 29% for giant adenomas. There were five surgical complications and no operative deaths. Ten out of 12 patients, who had undergone transseptal surgery previously, preferred the endonasal approach in terms of pain and ease of recovery. CONCLUSIONS: The direct paraseptal route for pituitary and pericellar tumor removal has an efficacy and complication rates comparable to those of the transseptal and sublabial routes. Patients generally recovered rapidly from this minimally invasive procedure and had no or minimal sinonasal complaints. For patients requiring a repeated operation, the paraseptal route appears to be less painful and easier to recover from, than the transseptal route.

Adenoma↗

PubMed2006

[Application of magnetoencephalography localization in brain tumor surgery].

OBJECTIVE: To evaluate the applied value of magnetoencephalography (MEG) localization in microsurgery of brain tumors in the region of motor cortex. METHODS: From January 2003 to April 2005, 36 patients with 19 meningomas, 14 gliomas, 2 metastases and 1 cavernous angioma underwent MEG and MRI before operation. These individualized functional brain maps were integrated into a neuronavigation system. Preoperative mapping of somatosensory and/or motor cortex was performed, and sites were compared, and all tumors were resected microsurgerically. RESULTS: A space-occupying lesion could change the region of motor cortex in all the patients. Thirty-four cases were resected totally. The patient's myodynamia after operation improved in 19 cases, unchanged in 15 cases, descended in 2 cases. CONCLUSIONS: MEG is an effective localization method of function, providing the relationship between the region of motor cortex and the tumor. And it is valuable for accurate planning in the treatment of brain tumors in the region of motor cortex.

Adolescent↗

PubMed2006

Pre- and intraoperative processing and integration of various anatomical and functional data in neurosurgery.

A software system is presented, capable of integrating various information sources for neurosurgical procedures. These include anatomical data such as a standard 3D DICOM image stacks, atlas data, as well as functional information (e.g. fmri, MEG, EEG). The system is programmed in C++ using Open GL for visualisation, and was developed in a close cooperation with a neurosurgical department to match existing needs. Preoperatively the data may be combined, registered by a rigid or elastic matching process, enriched by user specified planning information such as annotations or trajectories, and visualised in a standard fashion using different segmentation schemes, interactive rotation, zooming etc. Selected portions of the gathered and generated information may then be exported for neuronavigation input in DICOM or a vendor specific format. Intraoperatively, this information may, on the one hand, be simply used as an integrational part of the routinely used navigational data. On the other hand, the system is also capable of interacting with the navigational system to integrate the actual spatial information of the ongoing procedure into the preoperative data, thus allowing further planning and visualisation beyond the scope of the navigational unit. Furthermore, intraoperatively updated information such as intraoperative MR images or electrophysiological data may be integrated and correlated to the existing information. Ongoing developments comprise redistribution of the relevant data for injection onto the screen of the navigational system or into the optical pathway of the (3D capable) microscope display/ocular. This also includes information about the actual automatically optimized accuracy of the navigation process in relation to the head markers in use.

Humans↗

PubMed1997

Image guided excision of a ruptured feeding artery "pedicle aneurysm" associated with an arteriovenous malformation in a child: case report.

Excision of a ruptured aneurysm located at a lenticulostriate feeding artery associated with an arteriovenous malformation was performed using image guided neuronavigation in an 8-year-old child. The management of this lesion, which is rare in childhood, demonstrates the potential of combining frameless stereotaxy for precise target approach with conventional open microneurosurgery to minimize morbidity. Because of the unavoidable shifting of the brain that occurs during surgery, a catheter pointing towards the dome of the aneurysm was placed using image guidance prior to insertion of spatulae.

Aneurysm, Ruptured↗

PubMed1998

Preoperative planning and intraoperative navigation: status quo and perspectives.

An essential step in modern microneurosurgery involves preoperative planning of procedures. For difficult lesions neuronavigation is being used in conjunction with complex and detailed radiological investigations. This article shows how these examinations are used for computerized planning of surgical steps. Although planning and navigation are still two separate entities, the combination of the two may help in neurosurgery.

Aged↗