Stereotactic Neuronavigation System Research Articles

Successful Endoscopic Surgery Under Stereotactic Navigation for a Symptomatic Interhemispheric Arachnoid Cyst Without the Agenesis of the Corpus Callosum in an Elderly Patient: A Case Report

BACKGROUND AND IMPORTANCE: In adults and elderly patients, most arachnoid cysts are asymptomatic. Interhemispheric arachnoid cyst (IHAC) is clinically rare. In this report, we describe a rare case of a symptomatic IHAC without the agenesis of the corpus callosum in an elderly patient who underwent stereotactic endoscopic neurosurgery with excellent results. CLINICAL PRESENTATION: An 85-year-old woman with multiple systemic complications presented with progressive left hemiparesis. MR images, including diffusion tensor images, at the initial examination showed a large IHAC in the right parietal region without the agenesis of the corpus callosum. The patient underwent 3 MR image scans over the next year, and the lesions were markedly enlarged. Endoscopic cyst fenestration using a stereotactic neuronavigation system was performed between the IHAC and the bilateral ventricles. Postoperatively, the IHAC was reduced to a size sufficient to improve her hemiparesis. CONCLUSION: This is the first report of successful stereotactic endoscopic neurosurgery for a symptomatic IHAC without the agenesis of the corpus callosum. Further experience is required to confirm the usefulness of this minimally invasive procedure.

Neuronavigated Repetitive Transcranial Ultrasound Stimulation Induces Long-Lasting and Reversible Effects on Oculomotor Performance in Non-human Primates.

Since the late 2010s, Transcranial Ultrasound Stimulation (TUS) has been used experimentally to carryout safe, non-invasive stimulation of the brain with better spatial resolution than Transcranial Magnetic Stimulation (TMS). This innovative stimulation method has emerged as a novel and valuable device for studying brain function in humans and animals. In particular, single pulses of TUS directed to oculomotor regions have been shown to modulate visuomotor behavior of non-human primates during 100 ms ultrasound pulses. In the present study, a sustained effect was induced by applying 20-s trains of neuronavigated repetitive Transcranial Ultrasound Stimulation (rTUS) to oculomotor regions of the frontal cortex in three non-human primates performing an antisaccade task. With the help of MRI imaging and a frame-less stereotactic neuronavigation system (SNS), we were able to demonstrate that neuronavigated TUS (outside of the MRI scanner) is an efficient tool to carry out neuromodulation procedures in non-human primates. We found that, following neuronavigated rTUS, saccades were significantly modified, resulting in shorter latencies compared to no-rTUS trials. This behavioral modulation was maintained for up to 20 min. Oculomotor behavior returned to baseline after 18–31 min and could not be significantly distinguished from the no-rTUS condition. This study is the first to show that neuronavigated rTUS can have a persistent effect on monkey behavior with a quantified return-time to baseline. The specificity of the effects could not be explained by auditory confounds.

A Semi-Autonomous Stereotactic Brain Biopsy Robot With Enhanced Safety

In stereotactic brain biopsy, operating the needle accurately and taking the biopsy specimen safely are two major challenges for ensuring the success of the surgical procedure. Considering this fact, surgical robots offering high accuracy and precision have been developed for neurosurgery including brain biopsy. Typical brain biopsy robots are only commanded to adjust the needle's pose before inserting the needle manually by a neurosurgeon. In the literature, there exists no robotic system that is competent to complete the needle insertion task autonomously. To move a step forward, a novel biopsy module for brain biopsy is first designed and fabricated in this paper. The biopsy module can be automated to complete a series of tasks such as inserting the needle, generating and controlling the aspiration pressure for specimen acquisition, and rotating the cannula for side-cutting. The biopsy module is further integrated with a cost-effective and lightweight UR5 robot and an optical tracking system to improve the autonomy, leading to a stereotactic neuronavigation system. Kinematic relationships of the involved elements are established via a calibration process. A quadratic programming based approach equipped with a virtual potential field method is implemented to safely control the robot with joint-limit avoidance and obstacle avoidance capabilities. The experimentation of the brain biopsy robot is performed, demonstrating that the developed robotic system has potential applicability in the brain biopsy surgery.

Improving Accuracy for Optical Navigation in Asleep Deep Brain Stimulation Electrode Implantation

Abstract INTRODUCTION The authors sought to quantify the potential error in an optically guided stereotactic neuronavigation system, and demonstrate the repercussions of this error in clinical applications. All stereotactic systems have some degree of tolerated error in their design which may exceed that presumed by the surgeon; this may produce less accurate guidance, and suboptimal surgical outcomes if not taken into account. Surgeons should maintain an understanding of the fundamental limitations of the tools they employ to maximize surgical effectiveness. METHODS A passive optical intraoperative navigation system was used to simulate an asleep deep brain stimulation (aDBS) procedure with a “frameless” targeting system (NexFrame). Multiple configurations of the targeting system components were examined to determine the sources of error. Virtual entry point and target variations were recorded and compared with points obtained using an electromagnetic navigation system and with direct measurement. RESULTS The greatest source of error was the orientation of the targeting probe to the reference frame/camera system. Virtual entry point errors ranged between 0.12 and 1.4 mm, while target errors ranged between 0.2 and 2.4 mm (mean 0.85 mm, median 0.88 mm, standard deviation 0.24 mm). These errors produced a complex, reproducible pattern based on the orientation of the targeting probe. No orientation exceeded the tolerance limits programmed into the targeting software by the manufacturer. Representative configurations were tested for physical error using the electromagnetic system; physical errors between 1.2 mm-1.4 mm + /−0.4 mm were measured and visually confirmed. CONCLUSION Use of optically guided neuronavigation is expected to expand in the future. Successful utilization of this technology depends on an understanding of the limits of the systems. When high precision is critical, systems must be optimized beyond the manufacturer's built-in tolerances. Optimal orientation of the optical markers into a plane roughly orthogonal to the line of sight from the tracking cameras is crucial to maximize accuracy.

Use of Frameless Stereotactic Neuronavigation and O-arm for Transoral Transpalatal Odontoidectomy to Treat a Very High Basilar Invagination

Frameless stereotactic neuronavigation system has been in wide use since many years for precise localization of cranial tumors and navigation for spinal instrumentation. We present its usage in the localization of odontoid process in a very high basilar invagination for a transoral transpalatal resection of the same. We discuss the technical aspects of assembly of neuronavigation system, O-arm and Mayfield head frame on Allen spine system to achieve precise and accurate localization of high riding odontoid process through an extremely narrow operative corridor.

A systematic pipeline for the objective comparison of whole-brain spectroscopic MRI with histology in biopsy specimens from grade III glioma.

The diagnosis, prognosis, and management of patients with gliomas are largely dictated by the pathological analysis of tissue biopsied from a selected region within the lesion. However, the heterogeneous and infiltrative nature of gliomas make it difficult to identify the optimal region for biopsy with conventional magnetic resonance imaging (MRI). This is particularly true for low-grade gliomas, which are often nonenhancing tumors. To improve the management of patients with such tumors, neuro-oncology requires an imaging modality that can specifically identify a tumor's most anaplastic/aggressive region(s) for biopsy targeting. The addition of metabolic mapping using spectroscopic MRI (sMRI) to supplement conventional MRI could improve biopsy targeting and, ultimately, diagnostic accuracy. Here, we describe a pipeline for the integration of state-of-the-art, high-resolution, whole-brain 3-dimensional sMRI maps into a stereotactic neuronavigation system for guiding biopsies in gliomas with nonenhancing components. We also outline a machine-learning method for automated histological analysis that generates normalized, quantitative metrics describing tumor infiltration in immunohistochemically stained tissue specimens. As a proof of concept, we describe the combination of these 2 techniques in a small cohort of patients with grade 3 glioma. With this work, we aim to present a systematic pipeline to stimulate histopathological image validation of advanced MRI techniques, such as sMRI.

Stereotactic probability and variability of speech arrest and anomia sites during stimulation mapping of the language dominant hemisphere.

OBJECTIVE Functional mapping using direct cortical stimulation is the gold standard for the prevention of postoperative morbidity during resective surgery in dominant-hemisphere perisylvian regions. Its role is necessitated by the significant interindividual variability that has been observed for essential language sites. The aim in this study was to determine the statistical probability distribution of eliciting aphasic errors for any given stereotactically based cortical position in a patient cohort and to quantify the variability at each cortical site. METHODS Patients undergoing awake craniotomy for dominant-hemisphere primary brain tumor resection between 1999 and 2014 at the authors' institution were included in this study, which included counting and picture-naming tasks during dense speech mapping via cortical stimulation. Positive and negative stimulation sites were collected using an intraoperative frameless stereotactic neuronavigation system and were converted to Montreal Neurological Institute coordinates. Data were iteratively resampled to create mean and standard deviation probability maps for speech arrest and anomia. Patients were divided into groups with a "classic" or an "atypical" location of speech function, based on the resultant probability maps. Patient and clinical factors were then assessed for their association with an atypical location of speech sites by univariate and multivariate analysis. RESULTS Across 102 patients undergoing speech mapping, the overall probabilities of speech arrest and anomia were 0.51 and 0.33, respectively. Speech arrest was most likely to occur with stimulation of the posterior inferior frontal gyrus (maximum probability from individual bin = 0.025), and variance was highest in the dorsal premotor cortex and the posterior superior temporal gyrus. In contrast, stimulation within the posterior perisylvian cortex resulted in the maximum mean probability of anomia (maximum probability = 0.012), with large variance in the regions surrounding the posterior superior temporal gyrus, including the posterior middle temporal, angular, and supramarginal gyri. Patients with atypical speech localization were far more likely to have tumors in canonical Broca's or Wernicke's areas (OR 7.21, 95% CI 1.67-31.09, p < 0.01) or to have multilobar tumors (OR 12.58, 95% CI 2.22-71.42, p < 0.01), than were patients with classic speech localization. CONCLUSIONS This study provides statistical probability distribution maps for aphasic errors during cortical stimulation mapping in a patient cohort. Thus, the authors provide an expected probability of inducing speech arrest and anomia from specific 10-mm2 cortical bins in an individual patient. In addition, they highlight key regions of interindividual mapping variability that should be considered preoperatively. They believe these results will aid surgeons in their preoperative planning of eloquent cortex resection.

Corpus callosotomy in children with intractable epilepsy using frameless stereotactic neuronavigation: 12-year experience at The Hospital for Sick Children in Toronto

Although corpus callosotomy has been used effectively since the late 1930s to treat severe, medically intractable seizure disorders, particularly atonic or drop-attack seizures, controversy remains as to when, how, and how much surgery should be performed. Intraoperative determination of the extent of callosotomy, the need to stage the procedure, and the side of the interhemispheric approach represent technical issues that remain debatable. The authors report the 12-year experience of the senior author as well as surgical outcomes with corpus callosotomy using a frameless stereotactic neuronavigation system (ISG View Wand and BrainLab). Thirteen consecutive children at The Hospital for Sick Children underwent single-stage corpus callosotomy for medically intractable seizures. The mean age was 10.3 years. Five children underwent partial callosotomy, and 8 underwent complete callosotomy. The side of operative approach to avoid large parasagittal bridging veins was determined by preoperative study of 3D MR imaging/MR venography reconstructed by the neuronavigation system. The extent of callosotomy was determined using intraoperative feedback from the neuronavigation system and postoperative MR imaging. The extent of callosotomy determined by intraoperative neuronavigation and postoperative MR imaging correlated closely in all cases. There were no operative deaths. There was no significant postoperative morbidity related to venous infarction. Four of 5 patients in the partial callosotomy cohort and 7 of 8 patients in the complete callosotomy cohort showed significant improvement in seizure control. The use of frameless stereotactic neuronavigation is a safe, effective, and important surgical adjunct in the planning and execution of successful corpus callosotomy in children with intractable epilepsy.

Endoscopic resection of hypothalamic hamartomas for refractory symptomatic epilepsy

Hypothalamic hamartomas (HHs), rare developmental abnormalities of the inferior hypothalamus, often cause refractory, symptomatic, mixed epilepsy, including gelastic seizures. We present 37 patients with HH who underwent transcortical transventricular endoscopic resection. Between October 2003 and April 2005, 42 consecutive patients with refractory epilepsy who underwent endoscopic resection of HH were studied prospectively. The endoscope was held by an articulated pneumatic arm and tracked with a frameless stereotactic neuronavigation system. Data collection and follow-up were performed by personal interview. Five patients were excluded. The remaining 37 patients (22 males, 15 females; median age 11.8 years; range 8 months to 55 years) had frequent and usually multiple types of seizures. Postoperative MRI confirmed 100% resection of the HH from the hypothalamus in 12 patients. At last follow-up (median 21 months; range 13-28 months), 18 (48.6%) patients were seizure free. Seizures were reduced more than 90% in 26 patients (70.3%) and by 50% to 90% in 8 patients (21.6%). Overall, the mean postoperative stay was shorter in the endoscopic patients compared with our previously reported patients who underwent transcallosal resection (mean 4.1 days vs 7.7 days, respectively; p = 0.0006). The main complications were permanent short-term memory loss in 3 patients and small thalamic infarcts in 11 patients (asymptomatic in 9). Endoscopic resection of hypothalamic hamartoma (HH) is a safe and effective treatment for seizures. Its efficacy seems to be comparable to that of transcallosal resection of HH, but postoperative recovery time is significantly shorter.

Development of a Frameless and Armless Stereotactic Neuronavigation System with Ultrasonographic Registration

Development of a Frameless and Armless Stereotactic Neuronavigation System with Ultrasonographic Registration