SEARCH · PubMed Health

Results for “Neuronavigation”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 577 records · Page 32Linked to original sources

PubMed2004

Surface-based registration accuracy of CT-based image-guided spine surgery.

Registration is a critical and important process in maintaining the accuracy of CT-based image-guided surgery. The aim of this study was to evaluate the effects of the area of intraoperative data sampling and number of sampling points on the accuracy of surface-based registration in a CT-based spinal-navigation system, using an optical three-dimensional localizer. A cadaveric dry-bone phantom of the lumbar spine was used. To evaluate registration accuracy, three alumina ceramic balls were attached to the anterior and lateral aspects of the vertebral body. CT images of the phantom were obtained (1-mm slice thickness, at1-mm intervals) using a helical CT scanner. Twenty surface points were digitized from five zones defined on the basis of anatomical classification on the posterior aspects of the target vertebra. A total of 20 sets of sampling data were obtained. Evaluation of registration accuracy accounted for positional and rotational errors. Of the five zones, the area that was the largest and easiest to expose surgically and to digitize surface points was the lamina. The lamina was defined as standard zone. On this zone, the effect of the number of sampling points on the positional and rotational accuracy of registration was evaluated. And the effects of the additional area selected for intraoperative data sampling on the registration accuracy were evaluated. Using 20 surface points on the posterior side of the lamina, positional error was 0.96 mm +/- 0.24 mm root-mean-square (RMS) and rotational error was 0.91 degrees +/- 0.38 degrees RMS. The use of 20 surface points on the lamina usually allows surgeons to carry out sufficiently accurate registration to conduct computer-aided spine surgery. In the case of severe spondylosis, however, it might be difficult to digitize the surface points from the lamina, due to a hypertrophic facet joint or the deformity of the lamina and noisy sampling data. In such cases, registration accuracy can be improved by combining use of the 20 surface points on the lamina with surface points on other zones, such as on the both sides of the spinous process.

Analysis of Variance↗

PubMed2006

Frameless stereotaxy in a transmandibular, circumglossal, retropharyngeal cervical decompression in a Klippel-Feil patient: technical note.

Frameless stereotaxy, while most commonly applied to intracranial surgery, has seen an increasing number of applications in spinal surgery. Its use in the spine has been described to a greater degree in posterior rather than anterior surgical approaches, presumably due to the relative paucity of anatomical landmarks appropriate for frameless stereotactic registration in the anterior spine. This technical note illustrates the previously undescribed, successful use of frameless stereotaxy to the transmandibular, circumglossal, retropharyngeal surgical approach in a patient with Klippel-Feil syndrome.

Adult↗

PubMed2006

Computer-assisted screw insertion for cervical disorders in rheumatoid arthritis.

To reconstruct highly destructed unstable rheumatoid arthritis (RA) cervical lesions, the authors have been using C1/2 transarticular and cervical pedicle screw fixations. Pedicle screw fixation and C1/2 transarticular screw fixation are biomechanically superior to other fixation techniques for RA patients. However, due to severe spinal deformity and small anatomical size of the vertebra, including the lateral mass and pedicle, in the most RA cervical lesions, these screw fixation procedures are technically demanding and pose the potential risk of neurovascular injuries. The purpose of this study was to evaluate the accuracy and safety of cervical pedicle screw insertion to the deformed, fragile, and small RA spine lesions using computer-assisted image-guidance systems. A frameless, stereotactic image-guidance system that is CT-based, and optoelectronic was used for correct screw placement. A total of 21 patients (16 females, 5 males) with cervical disorders due to RA were surgically treated using the image-guidance system. Postoperative computerized tomography and plane X-ray was used to determine the accuracy of the screw placement. Neural and vascular complications associated with screw insertion and postoperative neural recovery were evaluated. Postoperative radiological evaluations revealed that only 1 (2.1%; C4) of 48 screws inserted into the cervical pedicle had perforated the vertebral artery canal more than 25% (critical breach). However, no neurovascular complications were observed. According to Ranawat's classification, 9 patients remained the same, and 12 patients showed improvement. Instrumentation failure, loss of reduction, or nonunion was not observed at the final follow-up (average 49.5 months; range 24-96 months). In this study, the authors demonstrated that image-guidance systems could be applied safely to the cervical lesions caused by RA. Image-guidance systems are useful tools in preoperative planning and in transarticular or transpedicular screw placement in the cervical spine of RA patients.

Aged↗

PubMed2002

Glioblastoma multiforme of the brain stem in a patient with acquired immunodeficiency syndrome.

Glioblastoma of the brain stem is rare and there is no description of such a lesion in patients suffering from acquired immunodeficiency syndrome. The majority of intracerebral mass lesions are due either to toxoplasmosis or primary central nervous system lymphomas so that it is usually not included in the differential diagnosis of enhancing lesions of the central nervous system in these patients. A 31-year-old human immunodeficiency virus (HIV) infected man presented with a four months history of slowly progressive deterioration of brainstem associated symptoms despite antitoxoplasmic therapy. Magnetic resonance imaging revealed a large ring enhancing lesion in the brainstem. Clinical and neuroradiological data could not establish a proper diagnosis and a stereotactic serial biopsy was undertaken. Histological examination of the specimen showed a glioblastoma multiforme (GBM) as the first reported case of GBM located in the brainstem in an acquired immunodeficiency syndrome (AIDS) patient. Patient management and effectiveness of stereotactic serial biopsy are discussed.

AIDS Dementia Complex↗

PubMed2004

Nocardia brain abscess mimicking brain tumour in immunocompetent patients: report of two cases and review of the literature.

Nocardia brain abscess is a rare intracranial lesion and has been reported in immunocompromised patients. An optimal treatment approach has not been established. However, early diagnosis and appropriate antimicrobial therapy are very important factors for a good outcome. We report two unusual cases of Nocardia brain abscess simulating brain tumour in immunocompetent patients. One of the cases was presumed to be a primary brain tumour and the other a metastatic brain tumour. They underwent surgical gross total resection. After Nocardia asteroides was seen on Gram's stain and subsequently identified by culture, appropriate antibiotic therapy was initiated.

Adolescent↗

PubMed2004

Intra-operative magnetic resonance imaging in neurosurgery.

Intra-operative MRI (iMRI) has been incorporated into modern neurosurgical operating rooms as a guide for neurosurgical interventions for almost ten years. This technology has been shown to be a useful modality in brain tumour surgery and biopsy; its use in spine, vascular and epilepsy surgery has been evolving. It is particularly useful in low-grade gliomas, pituitary adenomas and pediatric tumors. We evaluate currently available iMRI systems and their applications in neurosurgery. Future possibilities related to iMRI systems are mentioned in the light of current advances.

Adult↗

PubMed2005

Image guided interstitial laser thermotherapy: a canine model evaluated by magnetic resonance imaging and quantitative autoradiography.

OBJECTIVE: To determine the applicability and safety of a new canine model suitable for correlative magnetic resonance imaging (MRI) studies and morphological/pathophysiological examination over time after interstitial laser thermotherapy (ILTT) in brain tissue. MATERIAL AND METHODS: A laser fibre (Diode Laser 830 nm) with an integrated temperature feedback system was inserted into the right frontal white matter in 18 dogs using frameless navigation technique. MRI thermometry (phase mapping i.e. chemical shift of the proton resonance frequency) during interstitial heating was compared to simultaneously recorded interstitial fiberoptic temperature readings on the border of the lesion. To study brain capillary function in response to ILTT over time quantitative autoradiography was performed investigating the unidirectional blood-to-tissue transport of carbon-14-labelled alpha amino-isobutyric acid (transfer constant K of AIB) 12, 36 hours, 7, 14 days, 4 weeks and 3 months after ILTT. RESULTS: All laser procedures were well tolerated, laser and temperature fibres could be adequately placed in the right frontal lobe in all animals. In 5 animals MRI-based temperature quantification correlated strongly to invasive temperature measurements. In the remaining animals the temperature fibre was located in the area of susceptibility artifacts, therefore, no temperature correlation was possible. The laser lesions consisted of a central area of calcified necrosis which was surrounded by an area of reactive brain tissue with increased permeability. Quantitative autoradiography indicated a thin and spherical blood brain barrier lesion. The magnitude of K of AIB increased from 12 hours to 14 days after ILTT and decreased thereafter. The mean value of K of AIB was 19 times (2 times) that of normal white matter (cortex), respectively. CONCLUSION: ILTT causes transient, highly localised areas of increased capillary permeability surrounding the laser lesion. Phase contrast imaging for MRI thermomonitoring can currently not be used for reliable temperature readings in vivo. The suggested new canine model proved to be safe, accurate, easy to use, and provides clinical, radiographic, pathological and physiological correlations.

Aminoisobutyric Acids↗

PubMed2005

The use of virtual fluoroscopy in managing acute type II odontoid fracture with anterior single-screw fixation. A safe, effective, elegant and fast form of treatment.

BACKGROUND: The management of odontoid fractures represents both a clinical and a technical challenge due to the singular anatomy and biomechanics of the region. At present there is still much controversy as far as any form of management (surgical vs. conservative) is concerned and in any case there is not sufficient evidence to support a standardized form of treatment. This study was designed to further evaluate safety and efficacy of anterior odontoid single-screw fixation and to better determine the usefulness of Image Guided Surgery Virtual Fluoroscopy in treating such cases assessing also its advantages over traditional fluoroscopy and CT-guided frameless stereotaxy in the upper cervical spine surgery. METHODS: This was a retrospective review of ten patients presented during a short period of 18 months with acute traumatic Type II odontoid fractures. Nine underwent fixation within a mean of 3 days after injury, whereas a patient had to be operated upon on the 22nd day due to poor alignment with conservative treatment and ongoing instability. All patients postoperatively were fitted in a collar and then followed-up with serial clinical and radiographic examinations. FINDINGS: Radiological signs of fusion were seen in 10 cases (100%) (mean follow-up: 16 months). No complications occurred during the surgical procedure, nor were any instrumentation failures recorded; all patients remained neurologically intact. CONCLUSIONS: We believe that anterior odontoid screw fixation using Image Guided Surgery virtual fluoroscopy is a safe, effective, less time consuming and low x-ray exposure technique and we recommend this as the preferred treatment method for acute Type II odontoid fractures. Moreover, the use of image guided technology affords more precision, confidence and safety enabling the surgeon to approach the upper cervical spine in an easier and faster way.

Adult↗

PubMed2005

Ability of navigated 3D ultrasound to delineate gliomas and metastases--comparison of image interpretations with histopathology.

BACKGROUND: The objective of the study was to test the ability of a 3D ultrasound (US) based intraoperative imaging and navigation system to delineate gliomas and metastases in a clinical setting. The 3D US data is displayed as reformatted 2D image slices. The quality of the displayed 3D data is affected both by the resolution of the acquired data and the reformatting process. In order to investigate whether or not 3D US could be used for reliable guidance in tumour surgery, a study was initiated to compare interpretations of imaged biopsy sites with histopathology. The system also enabled concomitant comparison of navigated preoperative MR with histopathology. METHOD: Eighty-five biopsies were sampled between 2-7 mm from the tumour border visible in the ultrasound images. Biopsies were collected from 28 operations (7 low-grade astrocytomas, 8 anaplastic astrocytomas, 7 glioblastomas and 6 metastases). Corresponding cross-sections of preoperative MR T1, MR T2 and intraoperative US were concomitantly displayed, steered by the biopsy forceps equipped with a positioning sensor. The surgeons' interpretation of the images at the electronically indicated biopsy sites were compared with the histopathology of the samples. FINDINGS: The ultrasound findings were in agreement with histopathology in 74% (n = 31) for low-grade astrocytomas, 83% (n = 18) for anaplastic astrocytomas, 77% (n = 26) for glioblastomas and 100% (n = 10) for metastases. Excluding irradiated patients, the results for glioblastomas improved to 80% concurrence (n = 20). As expected tumour cells were found in biopsies outside the US visible tumour border, especially in low-grade gliomas. Navigated 3D US have a significantly better agreement with histopathology than navigated MR T1 for low-grade astrocytomas. CONCLUSION: Reformatted images from 3D US volumes give a good delineation of metastases and the solid part of gliomas before starting the resection. Navigated 3D US is at least as reliable as navigated 3D MR to delineate gliomas and metastases.

Adult↗

PubMed2006

New microsurgical technique for intraparenchymal lesions of the brain: transcylinder approach.

BACKGROUND: Although various minimally invasive approaches, including endoscopic, stereotaxic, and ultrasound-guided surgery, have been introduced to minimize damage to healthy brain tissue, the microsurgical technique has retained a significant role in contemporary neurosurgery. A new microsurgical approach to intraparenchymal brain lesions, namely, the transcylinder approach, was developed to realize both minimal surgical access and sufficient microsurgical technique. METHOD: A 0.1-mm transparent polyester film was used to create a cylindrical surgical route. The film was rolled into a thin stick and used to penetrate the brain, and a computer-aided navigation system was used from inside the stick to access the lesion accurately. After the stick gained access to the lesion, it was dilated to 2 cm, and this diameter was maintained during surgery. FINDINGS: The transcylinder approach was used in 11 cases, including intraparenchymal tumours and haematomas, and the usual microsurgical procedure was performed without difficulty. The film avoided unnecessary enlargement of the surgical field and minimized injury to the brain. Intra-operative ultrasonography also can be used to identify the lesion through the cylinder because the polyester film does not reflect the ultrasound beam. The surgical route was observed to recover to almost the same size as the initial cortical incision after removal of the cylinder. CONCLUSIONS: The transcylinder approach could be advantageous for removing tumours or haematomas in the intraventricular or intraparenchymal regions. By avoiding unnecessary retraction, it significantly reduces the risk of injury to surrounding brain tissue while facilitating precise microsurgical technique. The accuracy of this minimally invasive technique can be enhanced when used in conjunction with frameless stereotaxy and intra-operative ultrasound guidance.

Adolescent↗

PubMed2006

Frameless stereotactic subcaudate tractotomy for intractable obsessive-compulsive disorder.

Obsessive-compulsive disorder (OCD) is a chronic, disabling disorder. Psychosurgery may be indicated for a subset of patients for whom no conventional treatment is satisfactory. This paper focuses on the stereotactic subcaudate tractotomy (SST). Thus far, these procedures have been carried out using frame-based stereotactic techniques. However, modern - highly accurate - frameless stereotactic procedures have successfully been introduced in neurosurgical practice. We developed a novel frameless stereotactic subcaudate tractotomy procedure with promising initial results in a patient suffering from intractable OCD. This is the first report on frameless SST. Future studies should examine whether other ablative stereotactic psychosurgery procedures can be done using frameless stereotactic methods.

Afferent Pathways↗

PubMed2006

Primary germinoma arising from the midbrain.

A 29-year-old man presented with diplopia, dysarthria, anisocoria, oculomotor nerve paralysis, abducens nerve paralysis, right facial palsy, and spastic hemiparetic gait. Magnetic resonance imaging (MRI) showed a homogenously enhanced mass in the midbrain. MRI-guided stereotactic biopsy was performed, and the histologic diagnosis was pure germinoma. The tumor disappeared after chemotherapy and radiotherapy. Germinoma should be included in the differential diagnosis of midbrain lesions in young adults. MRI-guided stereotactic biopsy provided a helpful diagnostic clue in a patient with a midbrain lesion.

Adult↗

PubMed2002

Frame-based and frameless stereotaxy in the localization of cavernous angiomas.

Cavernous angiomas are mostly small intracranial vascular lesions which can be intraoperatively localized by sonography or stereotactic methods. This paper compares the results of cavernous angioma surgery localized by frame-based vs frameless techniques. Thirty-nine patients with cortical or subcortical lobar cavernoma were operated on by a microsurgical trans-sulcal approach. The localization of the lesion was performed in 19 (49%) patients by frame-based technique and in 20 (51%) patients by frameless navigation. In 22 (56%) of the patients, the cavernomas were located in an eloquent cortical area. Ten of 22 of these lesions were localized by frame-based stereotaxy and 12/22 by frameless navigation. The patients demonstrated the following preoperative symptoms: seizures 20 (51%), hemorrhage 18 (46%), focal neurologic deficit 11 (28%), and headache three (7%), and three (7%) were asymptomatic. Thirteen of 19 patients localized with frame-based stereotaxy were postoperatively asymptomatic or their preoperative neurological symptoms improved. Four of 19 had a transitory neurologic deficit and 2/19 a permanent worsening. Seventeen of 20 patients localized by frameless navigation were asymptomatic or neurologically improved. Three out of 20 suffered from a transient neurologic deficit. Regarding the seizures, 14 (70%) patients were postoperatively free of seizures, three (15%) were improved, and three (15%) were unchanged. The frameless navigation was superior regarding the flexibility for approaches along the skull base and midline, and the frame-based method was superior regarding the accuracy for very small lesions (less than 7 mm). In other cases, both methods were equal. Frame-based and frameless stereotactic methods are useful in the localization of small cavernous angiomas. They make it possible to remove cavernous angiomas in eloquent cortical regions with low risk of a permanent neurologic deficit.

Adolescent↗

PubMed2003

Computer-aided navigation in neurosurgery.

The article comprises three main parts: a historical review on navigation, the mathematical basics for calculation and the clinical applications of navigation devices. Main historical steps are described from the first idea till the realisation of the frame-based and frameless navigation devices including robots. In particular the idea of robots can be traced back to the Iliad of Homer, the first testimony of European literature over 2500 years ago. In the second part the mathematical calculation of the mapping between the navigation and the image space is demonstrated, including different registration modalities and error estimations. The error of the navigation has to be divided into the technical error of the device calculating its own position in space, the registration error due to inaccuracies in the calculation of the transformation matrix between the navigation and the image space, and the application error caused additionally by anatomical shift of the brain structures during operation. In the third part the main clinical fields of application in modern neurosurgery are demonstrated, such as localisation of small intracranial lesions, skull-base surgery, intracerebral biopsies, intracranial endoscopy, functional neurosurgery and spinal navigation. At the end of the article some possible objections to navigation-aided surgery are discussed.

Equipment Design↗

PubMed2006

Intraorbital lymphomas: neurosurgical experiences and management strategies.

Intraorbital lymphoma is a rare event. The aim of this study was to evaluate the clinical features, management, and outcome of patients with intraorbital lymphoma. The data of twenty-one individuals (12 women, nine men, aged 33 years to 84 years, mean age 62 years) with intraorbital lymphoma diagnosed between 1994 and 2003 were reviewed. Fifteen patients had no signs of systemic lymphoma disease. After the diagnosis of lymphoma had been surgically confirmed, chemotherapy alone was administered to seven patients, only radiotherapy was employed in nine, and both therapies were administered to five patients. With this treatment it was possible to obtain relief of orbital symptoms in 14 patients (67%) for at least 1 year. Three patients remain unchanged in their decreased visual capabilities. Local recurrence was observed in four cases and was treated with chemotherapy. Individualized microsurgical approaches to the orbit and adequate adjuvant therapy (radiotherapy, steroids, and chemotherapy, separate or in combination) are necessary to achieve satisfactory remission of orbital lymphomas.

Adult↗

PubMed2005

Intraventricular meningiomas: a report of 16 cases.

Meningiomas of the ventricle system are extremely rare. We report on a series of 16 intraventricular meningiomas (IVMs) treated at our institution between 1980 and 2004, with a special interest on the surgical outcome of using the intra/inter-parietal and parieto-occipital approach and the benefits of neuro-navigation. A retrospective analysis of the medical files for clinicoradiological findings, surgical interventions and surgical outcome was carried out. In 16 IVM patients with a female/male ratio of 11:5, age ranged from 24 years to 84 years (median 44 years). Duration of symptoms ranged from a few days to several years, and the cardinal symptoms were signs of increased intracranial pressure (86%), followed by corticospinal tract signs (43%), visual field defects (36%), cognitive changes (29%) and seizures (7%). The majority of tumours was located in the trigone (88%), and one was found in each the temporal horn and in the fourth ventricle. Tumour size ranged from 2.5 cm to 8 cm (median 5 cm), and the radiological appearance was uniform. The neuropathological workup revealed most IVMs as meningothelial, transitional (mixed) or lymphoplasmacyte-rich meningiomas (81%). Three tumours were classified as atypical (19%) and the MIB-1 proliferation index ranged from 1% to 40%. Complete resection was possible in all but one case. The trigonal IVMs were resected via an intraparietal/inter-parietal or parieto-occipital approach, and neuro-navigation was used in eight tumours. We encountered one perioperative death and one severely disabled patient. All other patients had a Glasgow outcome scale score of 5, and most of the pre-existing symptoms disappeared or improved after surgery. IVMs are a surgically curable tumour entity in most cases. The intraparietal/inter-parietal and parieto-occipital approach is very safe, and neuro-navigation allows early devascularisation of the tumour.

Adult↗

PubMed2005

[The reliability of stereotaxy in diagnosis of intracranial space occupying lesions].

A total of 79 patients with a suspect space occupying intracranial lesion was operated stereotactically. After CT and MR image acquisition, entry and target coordinates were defined and biopsy trajectories were simulated preoperatively using a special planning software. Biopsy specimens allowed a satisfactory neuropathological examination and diagnostic result in 74 of 79 (93.7%) cases. In the remaining 5 of 79 (6.3%) patients, a glioses was diagnosed in three cases; in only two patients could no pathological process be proved. 10 of 79 (12.7%) patients showed an intraoperative bleeding out of the biopsy-cannula during serial stereotaxy, which was associated with a CT-detectable hematoma up to 7 mm in diameter in only three cases (3.8%). In no patient was the detection of intracerebral bleeding the reason for any neurological deficit. In summary, the high percentage of satisfactory neuropathological diagnoses, the low rate of stereotaxy-associated morbidity and the comfortable and safe use of computer and stereotactic devices justify this kind of minimally invasive diagnostic measure as a routine method.

Adolescent↗

PubMed2005

Accuracy of stereotaxic positioning of transcranial magnetic stimulation.

In cognitive neuroscience, optically tracked frameless stereotaxic navigation has been successfully used to precisely guide transcranial magnetic stimulation (TMS) to desired cortical areas for brain-mapping purposes. Thereby, potential sources of imprecision are the fixation of a reference frame to the head of the subject and the referencing procedure according to certain landmarks (LM). The aim of our study was to evaluate the accuracy of frameless stereotaxic coil positioning in a standard experimental setting. A parameter for accuracy is the reproducibility of LM coordinates. In order to test the stability of the referencing for stereotaxic positioning within a single TMS session (within-session stability), the coordinates of six predefined facial LM in nine subjects were recorded first after the initial registration and second after a 20 minutes TMS session. The two sets of coordinates were then compared. The reliability of the positioning coordinates between different TMS sessions (inter-session repeatability) was addressed by registering the subjects LM coordinates in two independent TMS sessions. The variance of the recorded coordinates was analyzed. Altogether, LM were registered 1728 times (192 measures per subject). Within-session stability: The mean Euclidean distance (MED) between the LM position coordinates before and after a TMS session was 1.6 mm, when pooling over all LM. Inter-session repeatability: The MED between the LM positions recorded after the reference procedures of two different sessions showed an average deviation of 2.5 mm. In conclusion, optically tracked frameless stereotaxic coil positioning is from the technical viewpoint of high stability and repeatability. It is therefore a precise method for TMS brain mapping studies or for repeated TMS treatments, with the need of topographically exact stimulation.

Adult↗