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At least 595 records · Page 33Linked to original sources
PubMed2005

Frame-based stereotactic biopsy remains an important diagnostic tool with distinct advantages over frameless stereotactic biopsy.

OBJECT: As the availability of image-guided surgical navigation systems has increased, the application of frame-based biopsy has declined at our institution, despite equivalent accuracy and safety. There are several cost issues separating the use of surgical navigation systems and stereotactic frames for simple biopsy which may have implications in this era of health care cost control. We retrospectively reviewed the UCSF experience with stereotactic brain biopsy from a 9 year period. METHODS: Data were collected for 213 consecutive stereotactic brain biopsies performed at UCSF (139 frame-based and 74 frameless). There were no significant differences between the frame-based and frameless biopsy groups with regard to patient demographics, overall histopathology, proportion of nondiagnostic biopsies, or incidence of complications. General anesthesia was used for 9 (6%) and 70 (95%) of the frame-based and frameless biopsy cases, respectively. Frame-based biopsies required a mean of 114+/-3 min of operating room time, while frameless biopsies required 185+/-6 min (P<0.0001). For patients admitted to our neurosurgery service who underwent frame-based (n=110) or frameless (n=52) biopsy within 24 h of admission, the mean lengths of hospital stay were 1.8+/-0.2 and 3.2+/-0.6 days, respectively (P=0.007). CONCLUSION: Frame-based and frameless stereotactic biopsy approaches were equally effective at providing a tissue diagnosis with minimum morbidity and mortality. The frame-based approach, however, required significantly less anesthesia resources, less operating room time and shorter hospital stays, and thus should still be considered a first-line approach for stereotactic brain biopsy.

Adolescent↗
PubMed2006

Assessment of image guided accuracy in a skull model: comparison of frameless stereotaxy techniques vs. frame-based localization.

INTRODUCTION: The use of image-guided systems (IGS) for brain biopsy has increased in neurosurgical practice. We sought to evaluate the accuracy of a plastic, disposable burr hole mounted guide for stereotactic biopsy using an IGS and compare the results of different targeting methods with those of frame based localization. METHODS: MRIs were performed on a skull model with mounted fiducials with a stereotactic frame in place and data was loaded onto the Stealth IGS. The model was placed in a Mayfield head holder and fixed to the OR table. Registration of imaging to physical space was carried out. Using three different targeting methods on the Stealth IGS, the distance between the target and the predicted position of the target, the offset error, was measured in three dimensions and confirmed by 2 observers. A sum of squares for the 3 offset errors in all planes was used to calculate the summed vector error. The same MRI dataset used with the Cosman-Roberts-Wells (CRW) stereotactic frame for comparison. The summed vector error was calculated in the same manner to compare the accuracy of targeting with these guides to the frame-based CRW system. RESULTS: For frameless stereotaxy using the "Straight- guide 4 2D" targeting method the mean error was 2.58 +/- 0.51 mm (n=12). The vector error was 5.23 +/- 0.54 (n=4). For the registration set and target using the "Offset- guide 4 2D" targeting method the mean error was 1.66 +/- 0.36 mm (n=12). The vector error was 3.32 +/- 0.72 (n=4). The best localization was obtained with the "probe's eye" planning and targeting. The mean error was 0.33 +/- 0.16 mm (n=12). The vector error was 1.0 +/- 0.28 (n=4). We found a statistical difference between the different techniques (P<0.001) (Kruskal-Wallis One Way Analysis of Variance on Ranks). An all pairwise multiple comparison procedure (Holm-Sidak method) found an overall significance level = 0.05. For the frame-based CRW the mean error from the target was 1.03 +/- 0.19 mm (n=18) and the mean target localization error vector was 2.23 +/- 0.14 (n=6). We found a statistically significant difference between NDT guide "Probes Eye" vs. the MR-CRW (P=0.003, Mann-Whitney Rank Sum Test). CONCLUSIONS: These results indicate that using MR imaging, surgical planning software and the skull mounted Navigus-DT with the probe's eye view option for targeting, localization accuracy appears to fall within acceptable ranges compared with frame-based methods which have been the standards for stereotactic brain biopsy and functional neurosurgery. Furthermore, there may be considerable differences in accuracy between different targeting methods.

Biopsy↗
PubMed2005

Improvement of functional outcome after radical surgery in glioblastoma patients: the efficacy of a navigation-guided fence-post procedure and neurophysiological monitoring.

This retrospective study investigated the functional outcomes of patient with glioblastoma receiving radical surgery before and after the adoption of the navigation-guided fence-post (NGFP) procedure and neurophysiological monitoring. We investigated 42 glioblastoma patients receiving radical surgery in our institute between 1980 and 2005. Of the 42 patients, 18 patients from 1980 to 1996 (1st term) underwent radical surgery without navigation system guidance, NGFP, or neurophysiological monitoring; 11 patients from 1997 to 2002 (2nd term) underwent surgery with simple navigation system guidance but without NGFP procedure or neurophysiological monitoring, and 13 patients from 2003 to 2005 (3rd term) underwent surgery with the NGFP procedure and neurophysiological monitoring as appropriate. There were no significance differences between any of the three term groups in age, gender, preoperative KPS score, or 'surgical staging for glioma' according to the difficulty of surgery. The rates of 95% or greater volume reduction in each term were 38.9%, 54.5% and 76.9%. The rates of morbidity were 38.9%, 18.1% and 0%. The change in KPS scores (delta KPS) before and after the perioperative period in each term were -16.1 +/- 6.6 SEM, -9.0 +/- 5.8 SEM and +8.5 +/- 3.7 SEM, respectively. The delta KPS in the 3rd term was significantly better than those of 1st and 2nd terms (P < 0.01, Kruskal-Wallis rank test). The rate of patients who were discharged to home and who resumed daily useful life without assistance was 38.9%, 63.6% and 84.6% in each term, respectively. The mean survival times in each term were 9.9, 14.0 and 16.8 months. The introduction of the NGFP procedure and neurophysiological monitoring in glioblastoma radical surgery improved the functional outcome of patients.

Brain Neoplasms↗
PubMed2005

Comparing 0.2 tesla with 1.5 tesla intraoperative magnetic resonance imaging analysis of setup, workflow, and efficiency.

RATIONALE AND OBJECTIVES: To compare low-field with high-field intraoperative magnetic resonance imaging (MRI) in respect to setup, workflow, and efficiency. MATERIALS AND METHODS: A total of 750 patients were investigated either with a 0.2 T (March 1996-July 2001) or a 1.5 T (April 2002-August 2004) MRI system adapted for intraoperative use. RESULTS: With the low-field setup, 330 patients were examined in 65 months; with the high-field setup, 420 patients were examined in 29 months, which is a 2.8-fold increase in cases per month (14.5 versus 5.1) reflecting improved ease of use. Concerning intraoperative workflow, the time for preparation to start intraoperative imaging decreased fivefold (2 minutes instead of 10 minutes); navigation was applied more often with 57% versus 51% (240/420 versus 167/330), whereas functional data were integrated in 35% versus 39% (84/240 versus 65/167). Application of navigation updates was doubled (22% versus 11%; 53/240 versus 18/167). Image acquisition time was reduced by a factor of two, allowing a more detailed imaging protocol, whereas the image quality is clearly improved in the high-field setup, where there was no difference between the standard preoperative image quality compared with the intraoperative quality. This contributed to an increased detection of tumor remnants and extended resections in pituitary (36% versus 29%; 47/129 versus 17/59) and glioma surgery (41% versus 26%; 38/93 versus 28/106). CONCLUSION: Compared with the low-field setup, the high-field setup results not only in clearly superior image quality and increased imaging armamentarium, contributing to increased rates of detected tumor remnants, but also in a distinct improvement of intraoperative workflow. Furthermore, intraoperative high-field MRI offers various modalities beyond standard anatomic imaging, such as magnetic resonance spectroscopy, diffusion tensor imaging, and functional MRI.

Brain Diseases↗
PubMed2005

Navigator system-assisted endoscopic fenestration of a symptomatic cyst in the septum pellucidum--technique and cases report.

Expanding cysts of the septum pellucidum are rare and frequently manifest as intermittent headaches. Although the technique of endoscopic fenestration has been used since 1999, only a limited number of cases have been reported. We have added the use of a navigator system to guide keyhole creation and endoscopic access. To provide experience in navigator endoscopic treatment of symptomatic cyst of septum pellucidum and long-term follow-up of the surgical result. Under the guidance of the navigator system, a burr hole was made and rigid endoscope was inserted into the lateral ventricle through a working sheath. With direct visualization, only one side of the lateral wall of the cyst was fenestrated. And a grasping basket was used to further dilate the perforated hole. Patient A, a 14-year-old male adolescent, had an acute onset of severe headache with increased intracranial pressure. Patient B was a 37-year-old woman with a diagnosis of medically intractable migraine. Both patients experienced dramatic symptomatic relief after surgery at 4.5- and 2-year follow-up exams, respectively. The technique of navigator-assisted endoscopic fenestration in the treatment of a symptomatic cyst of the septum pellucidum might be a safe and effective method. It achieved satisfactory results in our two patients.

Adolescent↗
PubMed2007

CT-MR image data fusion for computer assisted navigated neurosurgery of temporal bone tumors.

PURPOSE: To demonstrate the value of multi detector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative work up of temporal bone tumors and to present, especially, CT and MR image fusion for surgical planning and performance in computer assisted navigated neurosurgery of temporal bone tumors. MATERIALS AND METHODS: Fifteen patients with temporal bone tumors underwent MDCT and MRI. MDCT was performed in high-resolution bone window level setting in axial plane. The reconstructed MDCT slice thickness was 0.8 mm. MRI was performed in axial and coronal plane with T2-weighted fast spin-echo (FSE) sequences, un-enhanced and contrast-enhanced T1-weighted spin-echo (SE) sequences, and coronal T1-weighted SE sequences with fat suppression and with 3D T1-weighted gradient-echo (GE) contrast-enhanced sequences in axial plane. The 3D T1-weighted GE sequence had a slice thickness of 1mm. Image data sets of CT and 3D T1-weighted GE sequences were merged utilizing a workstation to create CT-MR fusion images. MDCT and MR images were separately used to depict and characterize lesions. The fusion images were utilized for interventional planning and intraoperative image guidance. The intraoperative accuracy of the navigation unit was measured, defined as the deviation between the same landmark in the navigation image and the patient. RESULTS: Tumorous lesions of bone and soft tissue were well delineated and characterized by CT and MR images. The images played a crucial role in the differentiation of benign and malignant pathologies, which consisted of 13 benign and 2 malignant tumors. The CT-MR fusion images supported the surgeon in preoperative planning and improved surgical performance. The mean intraoperative accuracy of the navigation system was 1.25 mm. CONCLUSION: CT and MRI are essential in the preoperative work up of temporal bone tumors. CT-MR image data fusion presents an accurate tool for planning the correct surgical procedure and is a benefit for the operational results in computer assisted navigated neurosurgery of temporal bone tumors.

Adult↗
PubMed2006

Image-to-patient registration techniques in head surgery.

Frame-based stereotaxy was developed in neurosurgery at the beginning of the last century, evolving from atlas-based stereotaxy to stereotaxy based on the individual patient's image data. This established method is still in use in neurosurgery and radiotherapy. There have since been two main developments based on this concept: frameless stereotaxy and markerless registration. Frameless stereotactic systems ('navigation systems') replaced the cumbersome stereotactic frame by mechanically and later also optically or magnetically tracked instruments. Stereotaxy based on the individual patient's image data introduced the problem of patient-to-image data registration. The development of navigation systems based on frameless stereotaxy has dramatically increased its use in surgical disciplines other than neurosurgery, but image-guided surgery based on fiducial marker registration needs dedicated imaging for registration purposes, in addition to the diagnostic imaging that might have been performed. Markerless registration techniques can overcome the resulting additional cost and effort, and result in more widespread use of image-guided surgery techniques. In this review paper, the developments that led to today's navigation systems are outlined, and the applications and possibilities of these methods in the field of maxillofacial surgery are presented.

Cephalometry↗
PubMed2004

Navigation at the spine.

Computer aided and computer navigated operative techniques have been used for the first time in neurosurgery and surgery of the spine. For computer aided surgery of the spine there are currently two different methods: CT-based and C-arm based techniques. The advantage of the CT-based technique is its accuracy especially in difficult anatomical regions like the cervical and upper thoracic spine, and the possibility of preoperative planning. The advantage of C-arm navigation is the broad intraoperative availability with the disadvantage of limited image quality in some regions of the spine eg, the upper thoracic spine. This last disadvantage has been dramatically improved by introducing 3-D C-arm navigation (ISO C 3-D, Siemens, GER). Generally, all methods enhance the precision of pedicle screw insertion. Clinical as well as experimental studies show an exact pedicle screw position using the computer navigated techniques in over 90% of cases. C-arm based navigational techniques are being constantly improved and the future will be CT-like images with instant intraoperative availability.

Bone Screws↗
PubMed2006

Patient-specific model of brain deformation: application to medical image registration.

This contribution presents finite element computation of the deformation field within the brain during craniotomy-induced brain shift. The results were used to illustrate the capabilities of non-linear (i.e. accounting for both geometric and material non-linearities) finite element analysis in non-rigid registration of pre- and intra-operative magnetic resonance images of the brain. We used patient-specific hexahedron-dominant finite element mesh, together with realistic material properties for the brain tissue and appropriate contact conditions at boundaries. The model was loaded by the enforced motion of nodes (i.e. through prescribed motion of a boundary) at the brain surface in the craniotomy area. We suggest using explicit time-integration scheme for discretised equations of motion, as the computational times are much shorter and accuracy, for practical purposes, the same as in the case of implicit integration schemes. Application of the computed deformation field to register (i.e. align) the pre-operative images with the intra-operative ones indicated that the model very accurately predicts the displacements of the tumour and the lateral ventricles even for limited information about the brain surface deformation. The prediction accuracy improves when information about deformation of not only exposed (during craniotomy) but also unexposed parts of the brain surface is used when prescribing loading. However, it appears that the accuracy achieved using information only about the deformation of the exposed surface, that can be determined without intra-operative imaging, is acceptable. The presented results show that non-linear biomechanical models can complement medical image processing techniques when conducting non-rigid registration. Important advantage of such models over the previously used linear ones is that they do not require unrealistic assumptions that brain deformations are infinitesimally small and brain stress-strain relationship is linear.

Brain↗
PubMed2005

A stainless steel sheath for endoscopic surgery and its application in surgical evacuation of putaminal haemorrhage.

A stainless steel tube was used as an endoscope sheath in combination with a working channel endoscope to evacuate hypertensive putaminal intracerebral haematoma (ICH). A frontal entry point ipsilateral to the haematoma was selected for insertion of the sheath. From January to June 2004, seven patients with putaminal ICH underwent endoscopic surgery in our hospital. There were no surgical complications. Haematoma evacuation rates were greater than 90% (median of 93%). Six patients (87%) regained consciousness within one week. Six patients, including four who had no residual disability and two who had moderate disability, were able to function independently. One patient remained in a persistent vegetative state at clinical follow-up after 6 months. Use of a stainless steel endoscopic sheath combined with working channel endoscopy via a frontal approach facilitates evacuation of putaminal ICH.

Aged↗
PubMed2004

A deformable digital brain atlas system according to Talairach and Tournoux.

Brain atlases are valuable tools which assist neurosurgeons during the planning of an intervention. Since a printed atlas book has several disadvantages-among them the difficulty to map the information onto a patient's individual anatomy-we have developed a digital version of the well-established stereotaxic brain atlas of Talairach and Tournoux. Our atlas system is mainly dedicated to assist neurosurgical planning, and its benefits are: (i) a three-dimensional (3D) representation of most brain structures contained in the Talairach atlas; (ii) a nonrigid matching capability which warps the standard atlas anatomy to an individual brain magnetic resonance imaging (MRI) dataset in a few minutes and which is able to take deformations due to tumors into account; (iii) the integration of several sources of neuroanatomical knowledge; (iv) an interface to a navigation system which allows utilization of atlas information intraoperatively. In this paper we outline the algorithm we have developed to achieve 3D surface models of the brain structures. Moreover, we describe the nonrigid matching method which consists of two tasks: firstly, point correspondences between the atlas and the patient are established in an automatic fashion, and secondly these displacement vectors are interpolated using a radial basis function approach to form a continuous transformation function. To generate appropriate target structures for the first of these tasks, we implemented a quick segmentation tool which is capable to segment the cortex and ventricles in less than 5 min. An evaluation shows that our nonrigid approach is more precise than the conventional piecewise linear matching, though it should be further improved for the region around the deep grey nuclei. Summarizing, we developed a Win32 program which permits the convenient and fast application of standardized anatomy to individual brains which potentially contain tumors.

Algorithms↗
PubMed2005

Intraoperative MR imaging.

With the rapid evolution of technologic advances in neurosurgery, it is no surprise that the use of MR imaging to guide the performance of safe and effective surgical procedures is at the forefront of development. This article highlights the current capabilities of intraoperative MR-guided surgery for a variety of neurosurgical procedures and traces the evolution of the field to its present level of technical sophistication. The costs of intraoperative MR imaging and its future directions are discussed.

Biopsy↗
PubMed2004

Cyberknife radiosurgery for metastatic spine tumors.

Metastatic spine tumors affect a large number of patients each year, resulting in significant pain,destruction of the spinal column causing mechanical instability, and neurologic deficits. Standard therapeutic options include surgery and fractionated external beam radiotherapy. The first option can be associated with significant morbidity and limited local tumor control. Conversely, radiotherapy may provide less than optimal pain relief and tumor control, because the total dose is limited by the tolerance of adjacent tissues, such as the spinal cord. The emerging technique of spinal radiosurgery represents a logical extension of the current state-of-the-art radiation therapy. It has the potential to significantly improve local control of cancer of the spine, which could translate into more effective palliation and potentially longer survival. Spinal radiosurgery might offer improved pain control and a longer duration of pain control by giving larger radiobiologic doses.This technique also allows for the treatment of lesions previously irradiated using external beam radiation. Another advantage to the patient is that irradiation can be completed in a single day rather than several weeks, which is not inconsequential for patients with a limited life expectancy. In addition, cancer patients may have difficulty with access to a radiation treatment facility for prolonged daily fractionated therapy. This technique allows for the treatment of lesions previously irradiated using external beam radiation.Finally, the procedure is minimally invasive compared with open surgical techniques and can be performed in an outpatient setting. Similar to intracranial radiosurgery, stereo-tactic radiosurgery now has a feasible and safe delivery system available for the treatment of spinal metastatic lesions. The major potential benefit of radiosurgical ablation of spinal lesions is a relatively short treatment time in an outpatient setting combined with potentially better local control of the tumor with minimal risk of side effects. CyberKnife spinal radiosurgery offers a new and important alternative therapeutic modality for the treatment of spinal metastases in medically inoperable patients, previously irradiated sites, and for lesions not amenable to open surgical techniques or as an adjunct to surgery. Spinal radiosurgery is likely to become an essential part of any neurosurgical spine center that treats a large number of patients with spinal metastases.

Humans↗
PubMed2004

A stereotactic method for image-guided transcranial magnetic stimulation validated with fMRI and motor-evoked potentials.

Transcranial Magnetic Stimulation (TMS) delivers short magnetic pulses that penetrate the skull unattenuated, disrupting neural processing in a noninvasive, reversible way. To disrupt specific neural processes, coil placement over the proper site is critical. Therefore, a neural navigator (NeNa) was developed. NeNa is a frameless stereotactic device using structural and functional magnetic resonance imaging (fMRI) data to guide TMS coil placement. To coregister the participant's head to his MRI, 3D cursors are moved to anatomical landmarks on a skin rendering of the participants MRI on a screen, and measured at the head with a position measurement device. A method is proposed to calculate a rigid body transformation that can coregister both sets of coordinates under realistic noise conditions. After coregistration, NeNa visualizes in real time where the device is located with respect to the head, brain structures, and activated areas, enabling precise placement of the TMS coil over a predefined target region. NeNa was validated by stimulating 5 x 5 positions around the 'motor hotspot' (thumb movement area), which was marked on the scalp guided by individual fMRI data, while recording motor-evoked potentials (MEPs) from the abductor pollicis brevis (APB). The distance between the center of gravity (CoG) of MEP responses and the location marked on the scalp overlying maximum fMRI activation was on average less then 5 mm. The present results demonstrate that NeNa is a reliable method for image-guided TMS coil placement.

Algorithms↗
PubMed2005

The next generation of navigational technology.

Registration for image guidance has become significantly simplified and will continue to improve in accuracy. Unparalleled visualization of target tissues has been made possible through advances in imaging technologies,some of which have been modified to be employed directly in the operating room. With the advent of functional imaging techniques, the promise of functional rather than structural imaging suggests potentially fascinating interventions based on functional disturbances in tissue. Given the aggressive nature of the technology industry, some of the issues in surgical navigation discussed in this article have probably already been resolved and may be on their way to market. Undoubtedly, other points will also soon be addressed in novel and imaginative ways. As a result, the authors hope, the practice of rhinology will continue to evolve to improve the standard of care for patients. The future of many therapeutic interventions seems to be tied to the information infrastructure provided by information-guided therapy. Only through the innovative use of information-guided technology will further minimization of risks and maximization of benefit be achieved.

Endoscopy↗
PubMed2006

Reduction of intractable deafferentation pain by navigation-guided repetitive transcranial magnetic stimulation of the primary motor cortex.

The precentral gyrus (M1) is a representative target for electrical stimulation therapy of pain. To date, few researchers have investigated whether pain relief is possible by stimulation of cortical areas other than M1. According to recent reports, repetitive transcranial magnetic stimulation (rTMS) can provide an effect similar to that of electrical stimulation. With this in mind, we therefore examined several cortical areas as stimulation targets using a navigation-guided rTMS and compared the effects of the different targets on pain. Twenty patients with intractable deafferentation pain received rTMS of M1, the postcentral gyrus (S1), premotor area (preM), and supplementary motor area (SMA). Each target was stimulated with ten trains of 10-s 5-Hz TMS pulses, with 50-s intervals in between trains. Intensities were adjusted to 90% of resting motor thresholds. Thus, a total of 500 stimuli were applied. Sham stimulations were undertaken at random. The effect of rTMS on pain was rated by patients using a visual analogue scale (VAS) and the short form of the McGill Pain Questionnaire (SF-MPQ). Ten of the 20 patients (50%) indicated that stimulation of M1, but not other areas, provided significant and beneficial pain relief (p<0.01). Results indicated a statistically significant effect lasting for 3 hours after the stimulation of M1 (p<0.05). Stimulation of other targets was not effective. The M1 was the sole target for treating intractable pain with rTMS, in spite of the fact that M1, S1, preM, and SMA are located adjacently.

Adult↗
PubMed2005

Correlation of factors predicting intraoperative brain shift with successful resection of malignant brain tumors using image-guided techniques.

BACKGROUND: Intraoperative brain shift may cause inaccuracy of stereotactic image guidance on the basis of preoperatively acquired imaging data. The purpose of our study was to determine whether factors predicting brain shift affect the success of image-guided resection of malignant brain tumors. METHODS: We retrospectively studied 54 patients who underwent image-guided resections of histopathologically confirmed malignant brain tumors (9 metastases, 45 high-grade gliomas). Precautions were taken during surgery to minimize brain shift, but intraoperative imaging was not performed. The following factors predictive of intraoperative brain shift were assessed: tumor size, periventricular location, patient age, prior surgery or radiation therapy, patient positioning, use of mannitol, and length of operative time. Postoperative magnetic resonance imaging was obtained in all cases within 48 hours of surgery to assess extent of resection. RESULTS: Perioperative mortality was 0% in our series; perioperative morbidity was 3 of 54 patients (5.5%); 1 patient required reoperation for a hematoma, and 2 had transient neurological deficits. Successful resection was accomplished in 93% of tumors less than 30 cm(3) compared with 63.6% of tumors greater than 30 cm(3) (P = .026, Fisher exact test). This difference was more pronounced for patients with malignant gliomas. However, other factors predictive of intraoperative brain shift were not associated with unsuccessful resection. CONCLUSIONS: Intraoperative brain shift does not significantly affect the likelihood of successful resection of malignant brain tumors smaller than 30 cm(3). Larger tumors are less likely to be successfully resected, although factors other than brain shift can contribute to unsuccessful resection.

Adult↗