Articles: neuronavigation.
-
Journal of neurosurgery · Jun 2005
Clinical TrialFrameless stereotactic placement of depth electrodes in epilepsy surgery.
Depth electrodes are useful in the identification of deep epileptogenic foci. Computerized tomography-magnetic resonance (CT/MR)- and angiography-guided frame-based techniques are safe and accurate but require four-point skull fixation that limits cranial access for the placement of additional grids and strips. The authors investigated the viability and accuracy of placing depth electrodes by using a commercially available frameless system. ⋯ Depth electrodes can be placed safely and accurately by using a commercially available frameless stereotactic navigation system and a custom-made adapter. Depth electrode placement to record ictal onsets during epilepsy surgery only requires the contacts to touch rather than to reside within the intended structure. The laterotemporal approach is a more accurate method of placing electrodes than is the occipitotemporal one, likely due to the increased distance from the entry point to the target.
-
Journal of neuro-oncology · Jun 2005
Comparative StudyFrame-based stereotactic biopsy remains an important diagnostic tool with distinct advantages over frameless stereotactic biopsy.
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. ⋯ 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.
-
The Sonic Flashlight (SF) is a new handheld ultrasound (US) display device being developed at our institution. It replaces the standard monitor on a conventional ultrasound (CUS) system with a miniature monitor and half-silvered mirror to reflect real-time US images into the body. With the SF, the imaged body part appears translucent, with the US image appearing to float below the surface of the anatomy, exactly where it is being scanned. The SF merges the patient, US image, instrument, and operator's hands into the same field of view, allowing the user to operate directly on the US image using normal hand-eye coordination. In contrast, CUS procedures result in displaced hand-eye coordination when the operator looks away from the patient to view the CUS monitor. Intraoperatively, the SF may make localizing and accessing tumors, foreign bodies, hematomas, vascular malformations, and ventricles easier and more accurate, especially for those without extensive CUS training. ⋯ The needle was easily and intuitively visualized and guided into the lesion, both within and outside of the US plane. By having the US image appear directly beneath the brain surface, the surgeon can easily and quickly guide the needle or surgical instrument to the lesion. The operator's eyes never have to leave the surgical field, as they do with CUS technology. The impact of this device on neurosurgical procedures could be significant. The ease of use, intuitive function, and small instrument size allow the surgeon to quickly localize lesions, confirm surgical positioning, and assess postoperative results.
-
To evaluate, regardless of the clinical results, the contribution of combining functional magnetic resonance imaging (fMRI) with intraoperative cortical brain mapping (iCM) as functional targeting methods for epidural chronic motor cortex stimulation (MCS) in refractory neuropathic pain. ⋯ This study confirms the functional accuracy of fMRI guidance in neuropathic pain and illustrates the usefulness of combining fMRI guidance with iCM to improve the functional targeting in MCS. Because appropriate targeting is crucial to obtaining pain relief, this combination may increase the analgesic efficacy of MCS.
-
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. ⋯ 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.