This study investigated the number of epilepsy surgeries performed over time in Japan, and conducted a questionnaire survey of the Japan Neurosurgical Society (JNS) training program core hospitals to determine the current status and future objectives of surgical therapies and epilepsy training programs for physicians in Japan. This article presents part of a presentation delivered as a presidential address at the 44th Annual Meeting of the Epilepsy Surgery Society of Japan held in January 2021. The number of epilepsy surgeries performed per year has increased in Japan since 2011 to around 1,200 annually between 2015 and 2018. The questionnaire survey showed that 50% of the responding hospitals performed epilepsy surgery and 29% had an epilepsy center, and that these hospitals provided senior residents with education regarding epilepsy surgery. The presence of an epilepsy center in a hospital was positively correlated with the availability of long-term video electroencephalography monitoring beds as well as the number of epilepsy surgeries performed at the hospital. In regions with no medical facilities offering specialized surgical therapies for epilepsy, the JNS training program core hospitals may help improve epilepsy diagnosis and treatment. They may also increase the number of safe and effective surgeries by establishing epilepsy centers that can perform long-term video electroencephalography monitoring, providing junior neurosurgeons with training regarding epilepsy, and playing a core role in surgical therapies for epilepsy in tertiary medical areas in close cooperation with neighboring medical facilities.
Magnetic resonance (MR)-guided focused ultrasound surgery (MRgFUS) is the latest minimally invasive stereotactic procedure, and thalamotomy using this novel modality has demonstrated its effectiveness and safety, especially for patients with essential tremor (ET) and Parkinson’s disease (PD). In Japan, the application of MRgFUS to treat ET and PD has recently been covered by health insurance. Technically, the transducer with 1024 elements emits ultrasound beams, which are then focused on the target with a phase control, resulting in optimal ablation by thermal coagulation. The technical advantages of MRgFUS are continuous intraoperative monitoring of clinical symptoms and MR images and fine adjustment of the target by the steering function. Postoperative tremor control is compatible with other modalities, although long-term follow-up is necessary. The adverse effects are usually transient and acceptable. Prognostic factors for good tremor control include high temperature and large lesion size. A high skull density ratio is a factor to achieve high temperature and large lesioning, but it may not be necessary and sufficient for clinical outcomes. For patients with advanced symptoms such as bilateral tremor or head/neck tremor, deep brain stimulation may be recommended because of the adjustability of stimulation and the possibility of bilateral treatment. Patients have high expectations of MRgFUS because of its non-invasiveness. To perform this treatment safely and effectively, physicians need to understand the technological aspects, the physiological principles. To choose the appropriate modality, physicians also should recognize the clinical advantages and disadvantages of MRgFUS compared to other modalities.
In patients who undergo mechanical thrombectomy for intracranial large vessel occlusion, the occluded site is sometimes distal to the site shown in the initial vascular imaging. We investigated the factors related to the change in the occluded site between the sequential imagings. The 203 patients in the SKIP study were reviewed retrospectively. Magnetic resonance angiography (MRA) or computed tomography angiography (CTA) was used to assess the occluded site. The occluded site shown in the cerebral angiography appeared to be distal to the occluded site shown in the initial vascular imaging in 55 patients (group A). The location of the occluded site in the remaining 148 patients did not change between the sequential imagings (group B). MRA was used more often than CTA in group A (54 MRA, 1 CTA; P <0.01). Patients with middle cerebral artery (M1) occlusion were more likely to show change of the occluded site than patients with internal carotid artery (ICA) occlusion (M1: 38%, ICA: 9%; P <0.01). The number of patients who received intravenous recombinant tissue plasminogen activator did not differ between the two groups (group A: 54%, group B: 49%; P = 0.5). In patients with acute intracranial large vessel occlusion who require mechanical thrombectomy, physicians should be aware that the location of the thrombus may be distal to the occluded site shown in the initial vascular imaging, particularly in patients with M1 occlusion shown by MRA.
The significance of atypical histological features (AHF) as risk factors for recurrence in benign meningioma is not well understood. This study examined risk factors of World Health Organization (WHO) Grade I meningioma (GIM) recurrence, focusing on AHF. We investigated 150 consecutive newly diagnosed GIM patients who had more than one year of follow-up after resection in our hospital between January 2007 and March 2018. The following factors were reviewed retrospectively: age, sex, tumor location, extent of resection, MIB-1 index, mitotic figures, number and distribution of AHF, and recurrence. The patients were grouped according to the presence or absence of recurrence and comparatively examined. Recurrence was observed in 10 cases (6.7%). Univariate analysis showed that patients with recurrence had a significantly higher MIB-1 index (2.0 vs. 4.3; p = 0.006) and a significantly higher proportion of male patients (21.4% vs. 70.0%; p = 0.002) and patients with sheet-like growth (6.42% vs. 30.0%; p = 0.04). In multivariate analysis, skull base location (odds ratio [OR] 31.424; 95% confidence interval [CI] 1.74–569), gross total resection (OR 0.130; 95% CI 0.0189–0.897), and MIB-1 index (OR 1.939; 95% CI 1.19–3.15) were significantly associated with recurrence. Our study revealed that skull base location, subtotal resection, and high MIB-1 index were independent risk factors for recurrence. Only the presence of sheet-like growth had a significantly higher incidence in patients with recurrence in univariate analysis of AHF. Multivariate analysis found no significant association. Sheet-like growth may be involved in malignancy and recurrence of benign meningioma.
Subarachnoid hemorrhage (SAH) is a serious cerebrovascular disease with a high mortality rate and is known as a disease that is hard to diagnose because it may be overlooked by noncontrast computed tomography (NCCT) examinations that are most frequently used for diagnosis. To create a system preventing this oversight of SAH, we trained artificial intelligence (AI) with NCCT images obtained from 419 patients with nontraumatic SAH and 338 healthy subjects and created an AI system capable of diagnosing the presence and location of SAH. Then, we conducted experiments in which five neurosurgery specialists, five nonspecialists, and the AI system interpreted NCCT images obtained from 135 patients with SAH and 196 normal subjects. The AI system was capable of performing a diagnosis of SAH with equal accuracy to that of five neurosurgery specialists, and the accuracy was higher than that of nonspecialists. Furthermore, the diagnostic accuracy of four out of five nonspecialists improved by interpreting NCCT images using the diagnostic results of the AI system as a reference, and the number of oversight cases was significantly reduced by the support of the AI system. This is the first report demonstrating that an AI system improved the diagnostic accuracy of SAH by nonspecialists.
In cases of malignant gliomas located at language eloquent area, it is often difficult to preoperatively detect those area with functional MRI. Awake surgery is often used to spare the language eloquent area during surgery for such tumors; it is not available for a patient whose intracranial pressure is elevated due to the malignant tumor. The Wada test involves infusing anesthetic agents into the internal carotid artery to determine language dominancy before surgery for epilepsy or brain tumor. The super-selective Wada test is a technique to detect more detailed functional localization by infusing anesthetics into far distal middle cerebral artery branches. We present a 37-year-old man suffering from a left frontal lobe glioblastoma, in whom detection of an artery supplying Broca’s area was attempted by a super-selective Wada test. The super-selective Wada test successfully detected the branch of middle cerebral artery supplying Broca’s area. Total resection of the contrast-enhancing area was achieved without damaging the artery supplying Broca’s area without any neurological sequelae. This is the first report describing the usefulness of the super-selective Wada test in glioblastoma treatment. Our findings suggest that the super-selective Wada test is a powerful and useful means to distinguish the artery that supplies the language area from the tumor feeding artery in cases of tumors in the language eloquent area.
A lateral mass screw (LMS) is one of the standard anchor screws in posterior cervical fixation. Although the advantage of cervical LMS is that it is easier and safer to place than pedicle screw, it is sometimes difficult for surgeons to confirm the exact point for screw entry and accurate angle in cases of revision surgery. When LMS fixation is performed as revision surgery after cervical laminoplasty or laminectomy, it might be complicated to secure safe placement of the LMSs. We present a simple but practical technique involving a caliper and angle device for revision surgery after cervical laminoplasty for ossification of the posterior longitudinal ligament. In this technique, the distance between the bilateral entry points is ascertained using preoperative CT. Insertion of the screw is guided using the angle device set to 25 degrees. The technique presented here is easy and allows accurate placement of the LMSs in the posterior cervical spine, and is practical even for revision surgery.