Invention of an Online Interactive Virtual Neurosurgery Simulator With Audiovisual Capture for Tactile Feedback.

BACKGROUND: Present neurosurgical simulators are not portable. OBJECTIVE: To maximize portability of a virtual surgical simulator by providing online learning and to validate a unique psychometric method ("audiovisual capture") to provide tactile information without force feedback probes. METHODS: An online interactive neurosurgical simulator of a posterior petrosectomy was developed. The difference in the hardness of compact vs cancellous bone was presented with audiovisual effects as inclinations of the drilling speed and sound based on engineering perspectives. Three training methods (the developed simulator, lectures and review of slides, and dissection of a 3-dimensional printed temporal bone model [D3DPM]) were evaluated by 10 neurosurgical residents. They all first attended a lecture and were randomly allocated to 2 groups by the training D3DPM (A: simulator; B: review of slides, no simulator). In D3DPM, objective measures (required time, quality of completion, injury scores of important structures, and the number of instructions provided) were compared between groups. Finally, the residents answered questionnaires. RESULTS: The objective measures were not significantly different between groups despite a younger tendency in group A (graduate year -2.4 years, 95% confidence interval -5.3 to 0.5, P = .081). The mean perceived hardness of cancellous bone on the simulator was 70% of that of compact bone, matching the intended profile. The simulator was superior to lectures and review of slides in feedback and repeated practices and to D3DPM in adaptability to multiple learning environments. CONCLUSION: A novel online interactive neurosurgical simulator was developed, and satisfactory validity was shown. Audiovisual capture successfully transmitted the tactile information.

Hemodynamic changes during the obliteration process for cerebral arteriovenous malformations after radiosurgery.

OBJECTIVE: The process of cerebral arteriovenous malformation (AVM) obliteration following radiosurgery is poorly understood. Authors of this retrospective study aimed to assess the changes in AVM hemodynamics after stereotactic radiosurgery (SRS) by using 3D flow magnetic resonance imaging (MRI) to elucidate the process of AVM obliteration. METHODS: Twenty-four patients with AVMs treated with SRS between July 2015 and December 2017 were included in this study and classified into two groups depending on the duration of AVM obliteration: group A, obliteration within 3 years (n = 15); and group B, obliteration taking more than 3 years or no obliteration (n = 9). Blood flow (ml/min) in the largest feeding artery was measured before and after SRS by using time-averaged 3D flow MRI. The decreasing rate of blood flow in the feeding artery after SRS was calculated as the percent change from baseline blood flow. A Wilcoxon rank-sum test was used to compare the decreasing blood flow rate between the two groups at 4 and 12 months after SRS. RESULTS: For the entire cohort, the mean decrease in blood flow in the feeding artery from baseline was 29% at 4 months and 71% at 12 months after SRS. In general, blood flow after SRS decreased faster in group A and slower in group B. The decreasing rates in blood flow at 4 and 12 months after SRS were significantly different between the two groups (p = 0.02 and < 0.001, respectively). CONCLUSIONS: Tracking changes in AVM hemodynamics after SRS may be useful for assessing the progress of AVM obliteration and the therapeutic effects of SRS, possibly contributing to the prediction of subsequent obliteration outcome.

Accurate Preoperative Identification of Motor Speech Area as Termination of Arcuate Fasciculus Depicted by Q-Ball Imaging Tractography.

BACKGROUND: Tractography is one way to predict the distribution of cortical functional domains preoperatively. Diffusion tensor tractography (DTT) is commonly used in clinical practice, but is known to have limitations in delineating crossed fibers, which can be overcome by Q-ball imaging tractography (QBT). We aimed to compare the reliability of these 2 methods based on the spatial correlation between the arcuate fasciculus depicted by tractography and direct cortical stimulation during awake surgery. METHODS: In this study, 15 patients with glioma underwent awake surgery with direct cortical stimulation. Tractography was depicted in a three-dimensional computer graphic model preoperatively, which was integrated with a photograph of the actual brain cortex using our novel mixed-reality technology. The termination of the arcuate fasciculus depicted by either DTT or QBT and the results of direct cortical stimulation were compared, and sensitivity and specificity were calculated in speech-associated brain gyri: pars triangularis, pars opercularis, ventral precentral gyrus, and middle frontal gyrus. RESULTS: QBT had significantly better sensitivity and lower false-positive rate than DTT in the pars opercularis. The same trend was noted for the other gyri. CONCLUSIONS: QBT is more reliable than DTT in identification of the motor speech area and may be clinically useful in brain tumor surgery.

Two cases of symptomatic common carotid artery occlusion treated by carotid endarterectomy with L-shaped ministernotomy.

BACKGROUND: Common carotid artery occlusion (CCAO) is rare. Symptomatic lesions are resistant to medical treatment and revascularization are often required, but there is no consensus on the treatment of CCAO. In this paper, two cases of symptomatic CCAO treated by carotid endarterectomy (CEA) with L-shaped ministernotomy, in which the lesions extended to the beginning part of the CCA, are reported. CASE DESCRIPTION: Case 1 involved a 74-year-old man who presented with transient left limb numbness and an abnormal right visual field. Cerebrovascular angiography showed that the right CCA was occluded immediately after its origin and blood was supplied from the posterior circulation. CEA was performed with an L-shaped ministernotomy that allowed exposure of the CCA origin with minimal invasion. There were no complications associated with the sternal incision and he was discharged with a modified Rankin Scale (mRS) score of 0. Case 2 involved a 70-year-old man who presented with left half-blindness. Magnetic resonance imaging showed infarction in the right posterior cerebral artery region and neck echo showed CCA pseudo occlusion just before the carotid bulb. A new infarction in the right middle cerebral artery region developed during hospitalization. CEA with partial sternotomy was performed. The patient was rehabilitated with no deterioration of neurological findings and transferred with an mRS score of 3. CONCLUSION: There were no complications resulting from partial sternotomy in the two cases presented. CEA with partial sternotomy could be an effective treatment option for CCAO in which the internal carotid artery is patent and thrombus extends to the proximal CCA.

Anti-allergic effect of Perilla frutescens and its active constituents.

The leaves of Perilla frutescens Britton (Labiatae) are one of the most popular garnishes in Japan, used as an antidote for fi sh and crab meat allergy or as a food colorant. The present study was conducted to evaluate its anti-allergic effect and to identify its active constituents using mice ear-passive cutaneous anaphylaxis (PCA)-reaction. 48 h after the cutaneous injection of anti-ovalbumin serum into the ears of mice, ovalbumin and evansblue dye were intravenously injected. Perilla was extracted with boiling water, and intraperitoneally injected 15 min before ovalbumin-treatment. Thirty min after ovalbumin-treatment, the ears were removed and the colorant in the ear was colorimetrically quantitated. Perilla extract significantly suppressed the PCA-reaction, which was brought about by rosmarinic acid with a partial contribution from some macromolecular compounds. The anti-allergic titer of rosmarinic acid was more effective than tranilast, which is a modern anti-allergic drug. Perilla and rosmarinic acid are potentially promising agents for the treatment of allergic diseases.