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Purpose Endovascular treatment is technically challenging as distal anterior cerebral artery (DACA) aneurysms have distal location, small-caliber parent artery, and small size/wide neck. This study evaluated the feasibility and safety of the transradial approach (TRA) with a radial-specific neurointerventional guiding sheath as the first-line technique for DACA aneurysms. Methods We retrospectively analyzed an institutional database of consecutive patients with DACA aneurysm who underwent coil embolization using TRA. Ten consecutive patients were included in this study. After the radial-specific 6F Simmons guiding sheath (0.088″ inner diameter) was completely engaged into the target common carotid artery, a quadraxial system (6F Simmons guiding sheath/6F intermediate catheter/3.2F intermediate catheter/single microcatheter) was used for embolization. Then, we assessed for procedural success, angiographic outcomes, and procedure-related or vascular access site complications. Results Embolization procedures were conducted using simple coiling in eight and stent-assisted coiling with the trans-cell approach in two patients. The embolization procedure was successful in all patients (n = 10). Moreover, none presented with catheter kinking, parent artery flow stagnation, or system instability during the procedure. Immediate postprocedural angiography revealed complete obliteration in six and residual neck in four patients. Then, eight patients underwent follow-up angiography at a mean of 7.1 months, and none developed recanalization or required retreatment. The postprocedural course was uneventful, and there were no complications. Conclusion The transradial quadraxial system had the ability to achieve sufficient stability and kink resistance in DACA aneurysm embolization. Thus, this method was feasible and safe and had a high success rate.

Background Postoperative intracranial complications are rare in spine surgery not including cranial procedures. We describe an uncommon case of pseudohypoxic brain swelling (PHBS) and secondary hydrocephalus after transforaminal lumbar interbody fusion (TLIF) presenting as impaired consciousness and repeated seizures. Case presentation A 65-year-old man underwent L4-5 TLIF for lumbar spondylolisthesis and began experiencing generalized seizures immediately postoperatively. Computed tomography (CT) revealed diffuse cerebral edema-like hypoxic ischemic encephalopathy. He was transported to our hospital, at which time epidural drainage was halted and anti-edema therapy was commenced. His impaired consciousness improved. However, he suffered secondary hydrocephalus due to continuous bleeding from a dural defect and spinal epidural fluid collection 3 months later. Following the completion of dural repair and insertion of a ventriculoperitoneal shunt, his neurologic symptoms and neuroimaging findings improved significantly. Conclusions PHBS can be considered in patients with unexpected neurological deterioration following lumbar spine surgery even with the absence of documented durotomy. This might be due to postoperative intracranial hypotension-associated venous congestion, and to be distinguished from the more common postoperative cerebral ischemic events-caused by arterial or venous occlusions-or anesthetics complications.

Background The fence post technique, which involves insertion of catheters as fence posts around a tumor, has been widely used to demarcate the tumor border for maximal resection of intraparenchymal tumors, such as gliomas. However, a standard procedure for fence post insertion has not been established, and there are some limitations. To overcome this problem, a simple microscopic navigation-guided fence post technique was developed. The feasibility and efficacy of this novel technique during glioma surgery were assessed. Methods The microscopic navigation-guided fence post technique was used in 46 glioma surgeries performed in 42 patients. Intraoperatively, the preplanned trajectory was overlaid on the microscopic surgical field, and the microscope angle was changed until the entry and target points of the trajectory overlapped. A fence post catheter was inserted as planned under microscopic view, and the tumor was resected with fence post guidance. Preoperative tumor characteristics and surgical outcomes were evaluated. Results Mean age of patients was 50 years (range, 16–78 years), and 19 (45%) of 42 patients were women. Maximal safe resection was successfully achieved in 45 surgeries (97.8%), which was planned preoperatively with identification of the tumor border with fence posts without adverse effects of brain shift. No surgical complications attributable to fence post insertion occurred. Conclusions Clinical experience indicated that the microscopic navigation-guided fence post technique, in which fence posts can be placed without requiring the surgeon to take their eyes off the microscope, is safe and useful in glioma surgery.

Background Severe intraventricular hemorrhage (IVH) is associated with a high mortality rate and poor functional outcome, even with recent neurosurgical developments. IVH requires emergent surgery to save the patient's life, but the optimal surgical strategy remains controversial. We assessed the results obtained with our tailor-made endoscopic surgical strategy for severe IVH with obstructive hydrocephalus. Methods Consecutive patients with severe IVH owing to intracerebral hemorrhage who were treated with endoscopic surgery in the acute phase were retrospectively reviewed. Both rigid and flexible endoscopes were used for removal of hematoma in the whole ventricular system. Endoscopic third ventriculostomy and septostomy were performed as appropriate in each individual case. Results Eight patients met the inclusion criteria and were included in the analysis. Sufficient IVH removal without neglecting the fourth ventricle was achieved with our technique in 6 of 8 cases (75.0%). Endoscopic third ventriculostomy and septostomy were added in 4 cases each (50.0%). Four patients (50.0%) had a marked recovery and a good outcome (modified Rankin Scale score ≤2) despite disease severity at onset. The procedure was completed successfully in all cases, and there were no surgery-related complications. Conclusions This study showed that our tailor-made endoscopic surgical strategy for severe IVH with obstructive hydrocephalus may be beneficial.

Acromegaly is an acquired disorder usually caused by growth hormone-secreting pituitary adenoma, resolution of which requires correction of the excess hormone production. Recently, intraoperative magnetic resonance imaging (iMRI) was reported to be useful during the endoscopic endonasal approach (EEA) for pituitary adenoma. The present study was performed to quantitatively assess the role of iMRI in improving surgical outcomes in EEA for acromegaly. Twenty surgeries for acromegaly in EEA performed at Shinshu University Hospital between April 2016 and March 2020 were reviewed retrospectively. The inclusion criteria were cases without severe cavernous sinus tumor invasion (Knosp grade 0 – 3) or history of prior pituitary surgery. Fifteen consecutive patients were enrolled in this study. Clinical characteristics and postoperative clinical outcomes were compared between patients with and without use of iMRI during EEA for acromegaly. Conventional navigation-guided surgery was performed in nine patients, and six underwent iMRI-guided EEA for acromegaly. Gross total resection (GTR) was obtained in the six (100%) patients in the iMRI group, and in four (44.4%) patients in the conventional group without iMRI. Postoperative clinical outcomes, including hormonal remission rate and surgical complications, were comparable between the two groups. Although iMRI significantly increased the GTR rate, we found no direct evidence of increased hormonal remission rate by use of iMRI. It is important to confirm complete tumor resection carefully with not only iMRI findings, but also with intraoperative high-definition endoscopic direct visualization to increase the hormonal remission rate of acromegaly.

Segmental arterial mediolysis (SAM) is a rare non-arteriosclerotic and non-inflammatory vascular disease. Superficial temporal artery (STA) aneurysms are usually associated with trauma, surgery, and hair transplantation. Spontaneous aneurysms of the STA are uncommon, but an STA aneurysm caused by SAM is rare. We report a 70-year-old woman with a spontaneous aneurysm of the STA. The mass in the left parietal region was pulsatile and gradually enlarged in size without any history of head trauma. The mass was successfully removed by surgery and was proved histopathologically to be a true aneurysm with SAM.

Background Generally, asymptomatic epidermoid cysts (ECs) or ECs with minor symptoms controlled by medication are not treated further. Although epidermoid carcinomas are only sporadically reported, the possibility of malignant transformation of ECs is of concern. Case Description A 77-year-old man under observation for a left cerebellopontine angle tumor presented with no symptoms, including headache, dizziness, or other cranial nerve abnormalities typical of cerebellopontine angle tumors. The tumor manifested as an extra-axial mass in the left cerebellopontine angle and measured 24 × 16 mm (length × width) on magnetic resonance imaging (MRI). As he was asymptomatic, his primary physician did not pursue invasive treatment but ordered follow-up MRI every 2 years. The tumor decreased in size 2 years after the initial MRI, and no tumor fragmentation was observed on the patient’s spinal MRI. Ultimately, the tumor shrank to 19 × 11 mm over 22 years. Conclusions The reduction of an EC is extremely rare. We report a case of spontaneous regression of an EC and consider similar previous cases.

As there are many collateral pathways between venous systems, intraoperative venous injury rarely induces venous infarction. In some patients, however, venous injury during microsurgical manipulation may cause acute and/or delayed serious complications. Although intraoperative evaluation using indocyanine green (ICG) videoangiography is very useful, it is difficult to assess the flow direction using this technique. A simple technique using temporary clips and ICG videoangiography was applied to assess the collateral venous pathway in 4 cases of surgical manipulation-related injury or occlusion of the main superficial Sylvian vein in patients with aneurysm. The flow direction and collateral pathway can be easily visualized after release of temporary occlusion. A collateral venous pathway can be evaluated with the present simple technique described here.

Background In cardiac intervention, the transradial approach (TRA) is increasingly used as the first-line approach owing to numerous advantages over the transfemoral approach. Neurointerventional TRA, especially in intracranial interventions, is predominantly restricted to an alternative approach, as transradial carotid cannulation using a conventional transfemoral system can be technically challenging for patients with unfavorable acute takeoff of the target common carotid artery. This study evaluated the feasibility and safety of first-line TRA with a radial-specific neurointerventional guiding sheath for a large series of consecutive intracranial anterior circulation aneurysm embolizations. Methods We retrospectively analyzed our institutional database of first-line TRA for consecutive coil embolizations of anterior circulation aneurysms conducted between June 2018 and March 2020. A radial-specific 6-F Simmons guiding sheath (0.088-inch inner diameter) was engaged into the target common carotid artery, and subsequently a triaxial or quadraxial system was created for the embolization procedure. We assessed procedural success and procedure-related or vascular access site complications. Results A total of 119 patients with intracranial anterior circulation aneurysms underwent 121 coil embolization procedures. Of these, 101 patients who underwent 103 (85.1%) embolization procedures treated with first-line TRA were included. After the triaxial or quadraxial system was constructed, the embolization procedure was successful for all 103 cases without catheter kinking, system instability, or complications. Conclusions A transradial 0.088-inch triaxial or quadraxial system provided sufficient stability and kink resistance for intracranial aneurysm embolization. This method is feasible, highly successful, and safe for intracranial anterior circulation aneurysm embolization.

Objective In coronary intervention, the transradial approach (TRA) is increasingly used as the primary vascular access because of its numerous advantages over the transfemoral approach. However, in neurointerventions, conventional TRA with a straight-shaped guiding system is used as an alternative vascular access because transradial carotid cannulation can be technically challenging for right common carotid artery (CCA) lesions with steep angulation to the right subclavian artery or left CCA lesions with a nonbovine origin. The purpose of the present study was to evaluate the feasibility and safety of TRA as the primary vascular access with a pre-shaped Simmons guiding sheath for anterior circulation interventions. Methods Between June 2018 and September 2019, 130 consecutive patients (75 carotid artery stenting and 55 cerebral aneurysm coiling cases) who underwent TRA as the primary vascular access were included in this study. A 6-Fr Simmons guiding sheath was introduced into the target CCA by selecting a cannulation technique based on preprocedural image assessment. We retrospectively analyzed the carotid cannulation success, procedural success, and periprocedural or vascular access site complications. Results Carotid cannulation (69 right CCA, 6 left CCA with a bovine origin, and 55 left CCA with a nonbovine origin) and the subsequent procedure were successfully performed for all 130 patients without periprocedural or vascular access site complications. Conclusions TRA with a 6-Fr Simmons guiding sheath for anterior circulation interventions is highly successful and safe for all target CCAs and aortic arch types. This method can be utilized as the primary vascular access for anterior circulation interventions.

Background When medical devices and equipment in an operating room are connected to a network, vast amounts of data concerning the progress of the operation and the patient's condition can be comprehensively processed to improve the precision and safety of the surgical procedure. To make this possible, a next-generation networked operating room, “Smart Cyber Operating Theater” (SCOT), has been developed with medical-engineer cooperation. SCOT integrates stand-alone medical devices using the “OPeLiNK” communication interface. Using OPeLiNK, medical devices are connected and various data, such as intraoperative magnetic resonance imaging, neuromonitoring, biochemical monitoring, and navigation system, are integrated and displayed in the same timeline. Case Description The authors succeeded in clinical tumor resection via the endoscopic endonasal approach using the SCOT system in a 79-year-old man with a large nonfunctioning pituitary adenoma. The surgeons performed the operation while sharing information in real time between all staff in the operating room and supervising expert surgeons at the surgical strategy desk. Any decisions, such as intraoperative surgical procedures, were made with discussion between the operating room and the surgical strategy desk. The patient's postoperative course was uneventful. Conclusions This is the first case report of endoscopic endonasal approach performed successfully in the SCOT. Further developments in this technology may lead to innovations in not only microscopic neurosurgery but also endoscopic neurosurgery.

Meningiomas rarely progress to malignant variants and there is no consensus regarding the period over which malignant transformation may occur. Here, we report a case of anaplastic meningioma that showed malignant transformation 18 years after gross total resection of benign meningioma in the primary surgery, which may be the longest duration reported to date. Although the recurrence rate is low following total resection of benign meningioma, malignant transformation can rarely occur after a long period as in our case. Long-term follow-up after total resection of benign meningioma is suggested considering the risk of malignant transformation.

BACKGROUND: Radial artery access for cerebral angiography is traditionally performed in the wrist. Distal transradial access in the anatomic snuffbox is an alternative with several advantages. PURPOSE: Our aim was to review the safety and efficacy of distal transradial access for diagnostic cerebral angiography and neurointerventions. DATA SOURCES: We performed a comprehensive search of the literature using PubMed, Scopus, and EMBASE. STUDY SELECTION: The study included all case series of at least 10 patients describing outcomes associated with distal transradial access for diagnostic cerebral angiography or a neurointervention. DATA ANALYSIS: Random-effects models were used to obtain pooled rates of procedural success and complications. DATA SYNTHESIS: A total of 7 studies comprising 348 (75.8%) diagnostic cerebral angiograms and 111 (24.2%) interventions met the inclusion criteria. The pooled success rate was 95% (95% CI, 91%–98%; I(2) = 74.33). The pooled minor complication rate was 2% (95% CI, 1%–4%; I(2) = 0. No major complications were reported. For diagnostic procedures, the combined mean fluoroscopy time was 13.53 [SD, 8.82] minutes and the mean contrast dose was 74.9 [SD, 35.6] mL. LIMITATIONS: A small number of studies met the inclusion criteria, all of them were retrospective, and none compared outcomes with proximal transradial or femoral access. CONCLUSIONS: Early experience with distal transradial access suggests that it is a safe and effective alternative to proximal radial and femoral access for performing diagnostic cerebral angiography and interventions. Additional studies are needed to establish its efficacy and compare it with other access sites.

Background Recent advances in neuroendoscopic surgery have led to the minimally invasive treatment of brain abscesses using various endoscopy techniques. The endoscopic diving technique (EDT) involving the formation of fluid lenses to improve the visibility of the endoscope has been reported to be useful in the endoscopic endonasal approach (EEA) for pituitary and midline cranial base lesions. Here, we report a case of brain abscess treated endoscopically using EDT in cylinder surgery. Clinical presentation A 29-year-old man with 11q trisomy syndrome developed a fever and progressive right hemiparesis was observed. A diagnosis of a brain abscess was made based on neuroradiological imaging, and endoscopic irrigation and drainage with EDT via a transparent endoscopic sheath were performed, which provided a clear operative field and allowed satisfactory irrigation without bacterial contamination. The bacterium identified by PCR was Streptococcus intermedius, and antibiotic therapy was administered. Postoperatively, his symptoms gradually improved. Conclusion This is the first technical case report describing the clinical experience of EDT in brain abscess surgery. EDT may be a useful technique not only in EEA but also in cylinder surgery for brain abscesses.

BACKGROUNDIntraoperative magnetic resonance imaging (MRI) is useful for identifying residual tumors during surgery. It can improve the resection rate; however, complications related to prolonged operating time may be increased. We assessed the advantages and disadvantages of using low-field intraoperative MRI and compared them with non-use of iMRI during glioma surgery.METHODSThe study included 22 consecutive patients who underwent total tumor resection at Shinshu University Hospital between September 2017 and October 2020. Patients were divided into two groups (before and after introducing 0.4-T low-field open intraoperative MRI at the hospital). Patient demographics, gross total resection (GTR) rate, postoperative neurological deficits, need for reoperation, and operating time were compared between the groups.RESULTSNo significant differences were observed in patient demographics. While GTR of the tumor was achieved in 8/11 cases (73%) with intraoperative MRI, 2/11 cases (18%) of the control group achieved GTR (p=0.033). Seven patients had transient neurological deficits: 3 in the intraoperative MRI group and 4 in the control group, without significant differences between groups. There was no unintended reoperation in the intraoperative MRI group, except for one case in the control group. Mean operating time (465.8 vs. 483.6 minutes for the intraoperative MRI and control groups, respectively) did not differ.CONCLUSIONSLow-field intraoperative MRI improves the GTR rate and reduces unintentional reoperation incidence compared to the conventional technique. Our findings showed no operating time prolongation in the MRI group despite intraoperative imaging, which considered that intraoperative MRI helped reduce decision-making time and procedural hesitation during surgery.

A conchal non-pneumatized sphenoid sinus tends to be considered as unfavorable for transsphenoidal surgery because of procedural difficulties. Especially in acromegalic patients, the proportion of the conchal type of sphenoid sinus is potentially high compared with that of other patients who have a pituitary tumor. This report investigates the characteristics and surgery of the conchal type of sphenoid sinus in acromegaly along with the internal bone properties.A 70-year-old man with acromegaly underwent endoscopic endonasal transsphenoidal surgery. Intraoperatively, the anterior wall of the non-pneumatized sphenoid was cortical, however, the cancellous bone was very soft, included fatty tissue, and was easily removed by suction. The sellar lesion could be reached without any problems, and finally, total tumor resection was achieved.Based on this surgical case, the conchal sphenoid sinus of acromegaly is not always homogeneous solid bone but may contain soft fatty tissue. Therefore, although the sphenoidal characteristics may have an impact on the surgical procedures, precise assessment pre- and intraoperatively can make transsphenoidal surgery with conchal sphenoid sinus feasible.

Background The benefits of the right transradial approach for anterior circulation lesions using a 6F Simmonds guiding sheath have been reported. However, this technique can be anatomically challenging in the type I aortic arch. Furthermore, to the best of our knowledge, no studies have reported on neurointervention using a Simmonds guiding sheath and the left transradial approach. We devised a novel technique using the contralateral subclavian artery as an “anchor” to reform the Simmonds curve, named the subclavian artery anchoring technique (SCAT). The purpose of the present study was to evaluate the feasibility, safety, and usefulness of neurointervention with the SCAT for patients with a type I aortic arch treated with the right transradial approach and patients treated with the left transradial approach. Methods Ten consecutive patients treated from June 2018 to January 2019 were included in the present study. We retrospectively analyzed: 1) the success rate for reforming the Simmonds curve using the SCAT; 2) the success rate for introducing the 6F Simmonds guiding sheath into the target common carotid artery; 3) the success rate for completing the procedure; 4) periprocedural complications; and 5) vascular access site complications. Results In all 10 patients, the Simmonds curve was reformed, and a 6F Simmonds guiding sheath was introduced into the target common carotid artery. The procedure was successfully achieved for all 10 patients without periprocedural or vascular access site complications. Conclusions The results of the present study have shown that this technique is a feasible, safe, and useful method for patients with type I aortic arch treated with a right transradial approach or a left transradial approach. SCAT makes up for a deficiency in the transradial approach with a 6F Simmonds guiding sheath.

Several surgical procedures can be applied for syrinx associated with Chiari type 1 malformation; however, it remains controversial as to which approach is the most effective. Here, we evaluated the indications and limitations of foramen magnum decompression (FMD) with or without dural plasty. Forty patients with Chiari type 1 malformation were surgically treated and followed up for > 12 months. Thirty-two patients (80.0%) underwent FMD with removal of only the outer dura mater layer, while eight patients underwent FMD with dural plasty. We evaluated surgery-related complications and preoperative radiological findings affecting syrinx shrinkage rates. Post-surgery, the mean syrinx shrinkage rates were 0.32 ± 0.44 in the outer layer-removal group and 0.72 ± 0.27 in the dural plasty group (P = 0.012). Surgery-related complications were less frequent, but reoperation was more frequent, in the outer layer-removal group. The extent of tonsillar descent significantly affected syrinx shrinkage in FMD with outer layer removal (P = 0.042). The outcomes of both approaches in patients with tonsillar descent

Highlights • Motor threshold can be variable during surgery in TES-MEP. • The motor threshold in TES-MEP was influenced by intraoperative environmental changes. • The threshold change was greater on the affected side than on the unaffected side., Objective Motor threshold usually varies in the intraoperative motor evoked potential (MEP) by transcranial evoked stimulation (TES). This study investigated the degree of change in the motor threshold before and after surgery in TES-MEP monitoring with threshold criterion. This study aimed to evaluate the threshold change and discuss the factors influencing the motor threshold. Methods We retrospectively analyzed TES-MEP monitoring during supratentorial surgery with frontotemporal craniotomy in 72 patients without pre- and postoperative motor weakness. We analyzed the percentage changes between the affected and the unaffected sides, correlating the changes on the two sides. Results The percentage change on the affected and the unaffected side was 4.4 ± 15.1% and 0.4 ± 6.5%, respectively. The percentage change on the affected side was significantly larger than that on the unaffected side. A significantly positive correlation between the percentage change on the affected and the unaffected sides was detected. Conclusion The threshold for the TES-MEP varied significantly more than that on the unaffected side. Significance It is important to understand the characteristics of threshold variation for the evaluation of TES-MEP.

We present the case of a 74-year-old woman complaining of blurred vision in the left eye who was found to have a unilateral, continuous lesion of the optic nerve and nerve sheath accompanied by an intracranial mass next to the cavernous sinus and meninges. Surgical decompression of the left optic nerve in the optic canal and partial resection of the mass followed by prednisolone administration were successful. Immunohistochemical analysis disclosed abundant infiltration of IgG4-positive plasma cells at >10 cells/high power field. These findings indicated a new pattern of compressive optic neuropathy with confirmed IgG4 histopathological findings. Such an extensive lesion may produce visual disturbance.

Vestibular migraine (VM) commonly causes episodic vertigo/dizziness; however, its clinical features are unknown. Based on the evidence that central sensitization is related to VM pathogenesis, we hypothesized that cutaneous allodynia is frequently associated with patients with VM compared with patients without VM. This study aims to (1) elucidate the clinical features of patients with VM and (2) evaluate whether patients with VM were more frequently associated with cutaneous allodynia than patients without VM. This cross-sectional study enrolled consecutive patients with migraine aged 18–65 years. The comprehensive interview form included diagnostic questions regarding migraine and VM, demographic characteristics, migraine-specific variables, migraine-associated symptoms, and cutaneous allodynia. A total of 245 consecutive patients with migraine (mean age = 39.5 years, 81.2% women) were enrolled; 65 (26.5%) patients with VM were assigned to the VM group, 74 (30.2%) with migraine with vestibular symptoms not meeting the VM criteria (MwVS) were assigned to the MwVS group, and 106 (43.3%) patients with episodic migraine without vestibular symptoms (EM) were assigned to the EM group, respectively. Pairwise comparisons demonstrated no significant differences between the VM and MwVS groups, except for severe disability in the VM group. Compared with EM group, VM group had significant aura, severe disability, depression, tinnitus, sleep disorders, and widespread multimodal cutaneous allodynia. VM and MwVS may be on the same spectrum of disorders. The VM group had significantly associated widespread multimodal cutaneous allodynia compared with the EM group, indicating that thalamic sensitization plays a key role in VM pathogenesis. Widespread allodynia may be a useful diagnostic aid for VM.

The prognosis for spinal artery aneurysms associated with spinal cord arteriovenous malformations (AVMs) is poor because of the high rupture rate of aneurysms. However, endovascular treatment remains technically difficult because the catheter system must be constructed via the small-caliber anterior spinal artery (ASA) or posterior spinal artery (PSA), which feeds functionally eloquent spinal cord. A 2.6F Carnelian HF-S microcatheter (Tokai Medical Products, Aichi, Japan) has been specifically designed to assist a 1.6F Carnelian MARVEL S microcatheter (Tokai Medical Products) as a small-profile 'platform catheter' close to the target lesion. Here we present a prenidal ASA aneurysm treated using a 2.6F Carnelian HF-S microcatheter as an intraspinal canal platform catheter and review related literature.A 50-year-old man presented with a subarachnoid haemorrhage due to cervical spinal cord AVM. Diagnostic vertebral angiography revealed the AVM supplied by the PSA originated from the right C2 segmental artery and ASA arising from the right V4 segment. Superselective angiography for each feeder was achieved through a 2.6F Carnelian HF-S microcatheter, and a prenidal ASA aneurysm was diagnosed, which was clinically consistent with haemorrhagic origin. A 1.6F Carnelian MARVEL S microcatheter was cannulated into the aneurysm through the 2.6F Carnelian HF-S microcatheter positioned at the ASA. The aneurysm coiling was successfully performed without system instability or periprocedural complications.Only a few cases have described endovascular treatment for spinal artery aneurysms. To date, no reports have been published regarding the use of an intraspinal canal platform catheter to treat spinal artery aneurysms. A 2.6F Carnelian HF-S microcatheter served as a useful intraspinal canal platform catheter for coil embolization of the ASA aneurysm. This system can provide excellent accessibility and controllability for endovascular treatment of spinal artery lesions.

BACKGROUND Intraoperative flash stimulation visual evoked potential (VEP) monitoring has been used for endoscopic endonasal approach (EEA). Recently, off-response VEP, which is recorded when the light stimulus is turned off, was introduced to monitor visual function intraoperatively. OBJECTIVE To evaluate off-response VEP monitoring in comparison with the conventional flash stimulation VEP monitoring for EEA. METHODS From March 2015 to March 2020, 70 EEA surgeries with intraoperative VEP monitoring (140 eyes) were performed. Light stimuli were delivered by a pair of goggle electrodes. Recording electrodes were placed on the scalp over the occipital region. The warning signal was prompted by a reduction of the peak-to-peak amplitude of the VEP by more than 50% compared to the initial amplitude. Visual function was assessed pre- and postoperatively. Results of flash and off-response VEP monitoring were compared. RESULTS VEP was recorded in 134 eyes. Warning signal occurred in 23 eyes (transient in 17 eyes and permanent in 6 eyes). Two eyes showed permanent VEP attenuation for flash VEP monitoring, in which one patient had postoperative visual function deterioration. Four eyes showed permanent VEP attenuation for off-response VEP monitoring, where 2 patients had postoperative visual function deterioration. Sensitivity, specificity, positive predictive value, and negative predictive value were 100%, 98.9%, 50%, and 100%, respectively, for flash stimulation VEP, and 100%, 97.8%, 50%, and 100%, respectively, for off-response VEP. CONCLUSION VEP monitoring was useful to monitor visual function in EEA surgery. Off-response VEP monitoring was not inferior to conventional flash stimulation VEP monitoring.

Background: The demographic and clinical characteristics of vestibular migraine (VM) based on the International Classification of Headache Disorders (ICHD)-III beta are not well documented, and the underlying pathophysiology remains largely unknown. Based on evidence that central sensitization is involved in VM pathogenesis, we hypothesized that cutaneous allodynia (CA), which is a clinical manifestation of central sensitization, and interictal widespread pressure hyperalgesia (IWPH), which may be an accelerator for central sensitization, are more frequently associated with VM patients compared with non-VM patients. The aim of this study was as follows: 1) to assess differences in demographic and clinical characteristics among VM patients, patients with migraine with vestibular symptoms not meeting VM criteria (MwVS), and patients with migraine without vestibular symptoms (MwoVS); and 2) to evaluate whether VM patients were more frequently associated with CA/IWPH compared with the other two groups.Methods: This cross-sectional study enrolled consecutive migraine patients, aged 18–65. The comprehensive interview form included diagnostic questions of migraine and VM, demographic characteristics, migraine-specific variables, migraine-associated symptoms, and CA. IWPH occurrence was investigated using a manual tender point survey and clinical parameters were compared.Results: A total of 245 episodic migraineurs (mean age = 39.5 ± 11.3 years, 81.2% women) were enrolled. Based on ICHD-III beta criteria, 65 (26.5%), 74 (30.2%), and 106 (43.3%) patients were assigned to the VM group, MwVS group, or MwoVS group, respectively. Pairwise comparisons demonstrated no significant differences between the VM and MwVS groups, except for higher occurrence of headache disability in the VM group. Compared with the MwoVS group, the VM group was significantly associated with aura, severe disability, depression, tinnitus, sleep disorders, multimodal CA, and IWPH.Conclusions: There were no significant differences in clinical features between VM and MwVS groups, except for disability, which was possibly caused by criteria selection bias. VM and MwVS may be on the same disease process spectrum. Widespread multimodal CA, including clinical manifestations of thalamic sensitization, was significantly associated with VM patients compared with MwoVS patients, which indicates that thalamic sensitization may play a key role VM pathogenesis. Furthermore, IWPH may enhance susceptibility to thalamic sensitization.

Background A next-generation networked operating room, Smart Cyber Operating Theater (SCOT), has been developed in cooperation with medical engineers that integrates standalone medical devices, including intraoperative magnetic resonance imaging (MRI) using the OPeLiNK communication interface. Here, we report the application of this newly developed advanced type of operating theater for the endoscopic endonasal approach (EEA), along with an evaluation of our initial experiences. Methods The study population consisted of 18 patients with parasellar tumor. All patients underwent surgery via the EEA in SCOT. During all procedures, various types of intraoperative information, including electrophysiologic monitoring, anatomic orientation with navigation system, intraoperative MRI, and endoscopic images of the operative field, were collected and stored by OPeLiNK. Furthermore, the intraoperative information was shared with the surgical strategy desk, where a senior neurosurgeon can direct and manage the surgical procedure in real-time. Results We successfully completed the surgical procedures in SCOT in all cases. Using OPeLiNK, operators in SCOT were able to share various data, such as images obtained intraoperatively and surgical instrument position from navigation systems, as well as images of the surgical field, with senior neurosurgeons at the surgical strategy desk in all cases. Surgically relevant information from these sources was transmitted through an application and displayed to all surgical staff. The necessary nuances were reflected in the surgical procedures. Conclusions SCOT, which is considered an innovative operation system in neurosurgery, enables both quality and safety in the EEA. Furthermore, the use of SCOT may also contribute to the education of young neurosurgeons.

Background Spontaneous cerebrospinal fluid (CSF) rhinorrhea associated with untreated prolactinomas is rare, which is in contrast to medical treatment-induced CSF rhinorrhea. Previous studies have suggested that cessation of drug administration should be the first line of treatment for prolactinoma with medically induced CSF rhinorrhea. On the other hand, there is no standard treatment strategy for prolactinoma with the development of spontaneous CSF rhinorrhea, because of its complicated pathology. Here, we report a case of giant invasive macroprolactinoma with spontaneous CSF rhinorrhea, and discuss the treatment strategy for this complicated condition with a review of the relevant literature. Case Description A previously healthy 39-year-old man presented with 1-year history of intermittent clear fluid nasal discharge with headache and vomiting. Magnetic resonance imaging showed a large parasellar mass with destruction of the skull base. This tumor was diagnosed as prolactinoma with hypopituitarism based on the results of hormone examinations. Tumor resection with skull base reconstruction in the endoscopic endonasal approach was performed because CSF rhinorrhea was aggravated by bromocriptine loading test and administration of dopamine agonist. Life-threatening bacterial meningitis occurred after surgery, which was cured with antibiotics along with resolution the CSF rhinorrhea. Conclusions Careful consideration is necessary before applying standard first-line protocols with dopamine agonist administration in patients with prolactinoma, especially in cases with spontaneous CSF rhinorrhea. An appropriate treatment strategy should be planned according to the individual case, including factors such age, sex, pituitary function, tumor mass size, prolactin concentration, and condition of CSF leakage.

Background Primary dedifferentiated liposarcoma of the orbit is a rare condition. Case Description A 41-year-old man presented with a history of right ophthalmalgia with eye movement and exophthalmos that had developed 2 months earlier. Neuroimages revealed a right orbital mass located above the superior rectus muscle. Tumor resection through the right frontal craniotomy was performed. Histopathologic findings showed the dedifferentiated liposarcoma. Conclusions Primary orbital dedifferentiated liposarcomas remain challenging for their diagnosis and standard treatment. Clinicians should keep in mind the possibility of liposarcoma with orbital tumors.

Pediatric reversible cerebral vasoconstriction syndrome (RCVS) and spontaneous cervical internal carotid artery (ICA) vasospasm are rare conditions; the former is commonly associated with a favorable prognosis. A healthy 13-year-old girl presented with thunderclap headache, followed by left hemiparesis, during a curling match. Six days after onset, left hemiparesis worsened to hemiplegia. Magnetic resonance imaging showed progressive cerebral infarction caused by severe right middle cerebral artery and cervical ICA stenosis. She became comatose because of impending uncal herniation. Emergent surgical decompression was performed. Then, 59 days after onset, her multiple stenoses improved, which was consistent with RCVS concomitant with spontaneous cervical ICA vasospasm. This is the first case of RCVS that concurrently developed spontaneous cervical ICA vasospasm. The patient developed life-threatening stroke due to the hemodynamic impairment of the affected intracranial and cervical arteries. Spontaneous extracranial supra-aortic artery vasospasm can be a poor prognostic predictor of RCVS.

Purpose Endovascular treatment for subclavian artery (SA) occlusive disease is well established; however, a potential risk remains for posterior circulation embolism, which can be life threatening. To reduce the risk of vertebral artery (VA) embolism, we have devised a transradial dual-balloon protection system referred to as the balloon switching technique. Herein, we describe a patient with left SA stenosis who successfully underwent SA stenting using the balloon switching technique. Case presentation A 79-year-old woman with left arm claudication was diagnosed with left subclavian steal syndrome due to severe stenosis of the proximal left SA. Endovascular revascularization using the balloon switching technique was employed. To obtain VA embolic protection during device advancement through the SA lesion, an 8F balloon-guiding catheter was inflated in the left SA at the level of the VA takeoff using the left transradial sheathless approach. A balloon-expandable stent was inflated in the SA lesion, followed by deflation of the balloon-guiding catheter. The stagnant left VA flow was flushed away toward the distal left SA. Following reinflation of the balloon-guiding catheter, the stent delivery system was deflated and removed. Floating debris in the SA proximal to the balloon-guiding catheter was adequately aspirated, followed by deflation of the balloon-guiding catheter. Left SA angiography showed successful revascularization, and postprocedural neuroimaging showed no evidence of ischemic stroke. Conclusions The balloon switching technique reduces the risk of VA embolism during left SA stenting via the transradial access. This method is a useful therapeutic option for patients with left SA occlusive disease.

Background Mechanical endovascular embolectomy using stent retrievers has gained popularity for treatment of large vessel occlusion in acute ischemic stroke. Use of open embolectomy as a direct surgical treatment has been limited, likely owing to the technical difficulty, therapeutic time window, and time-consuming procedure. Methods We retrospectively reviewed clinical and radiographic records of patients who underwent open embolectomy for major artery occlusion at an acute stage. Clinical features, complications, and outcome of patients were analyzed. Results From January 2004 to September 2016, 153 patients underwent 157 open embolectomies for major artery occlusion. Complete recanalization was achieved in 96.2% of patients. A favorable outcome was observed in 43.9%. Cerebral aneurysm along the occluded artery was observed in 11 patients with 12 aneurysms. Conclusions Open embolectomy resulted in a high complete recanalization rate with an acceptable safety profile. Open embolectomy is a safe and durable method of cerebral recanalization in patients with embolic stroke and can be considered as a potential treatment if endovascular embolectomy cannot be performed. The details of the occluded arteries presented here will be useful for endovascular surgeons to prevent complications.

Middle cerebral artery (MCA) aneurysms usually arise at the primary MCA bifurcation or trifurcation. Distal MCA aneurysms are rarely considered as sources of aneurysmal subarachnoid hemorrhage (SAH). It has been reported that ruptured distal MCA aneurysms are associated with head trauma, neoplastic emboli, arterial dissection, or bacterial infection. We experienced five cases of ruptured distal MCA aneurysms and evaluated their clinical characteristics. Retrospective analysis of aneurysmal SAH at Kobayashi Neurosurgical Neurological Hospital was performed from January, 2004 to December, 2014. Clinical characteristics of ruptured distal MCA aneurysms were analyzed using our database. Among 191 aneurysmal SAH patients, there were five ruptured distal MCA aneurysms. All patients did not have any specific medical problems such as infectious disease, head trauma, or cardiac disorders. The incidence of ruptured distal MCA aneurysm was higher than expected and was equivalent to 9.4% of the total ruptured MCA aneurysms. Strong male predominance (80%) and M2-3 junction aneurysm preponderance (80%) were observed. In addition, there were only two patients (40%) with intracerebral hematoma in our study. We reported five cases of ruptured distal MCA aneurysms. Although ruptured distal MCA aneurysms are thought to be rare as sources of aneurysmal SAH, the incidence of ruptured distal MCA aneurysm was 9.4% of all ruptured MCA aneurysms in our study. Ruptured distal MCA aneurysms should be considered as sources of aneurysmal SAH without intracerebral hematoma.

Posterior inferior cerebellar artery (PICA) aneurysms are often located in the ventral craniocervical junction. Such deep-seated aneurysms are usually treated with coil embolization. However, recurred and/or very small PICA aneurysms are hardly treated with an endovascular approach. We present a modification of the transcondylar fossa approach with intradural and extradural removal of the jugular tubercle. An adequate preaccessory surgical corridor was created with this novel technique. The ventocaudal PICA aneurysm was clipped through the outside of the spinal accessory nerve without surgical manipulation of other lower cranial nerves. This approach is worthwhile to avoid dysphagia.

Nonpenetrating titanium clips create no suture holes and thereby reduce cerebrospinal fluid leakage after dural closure. However, no data exist regarding metallic artifacts caused by these clips during postoperative neuroimaging. We aimed to evaluate clip-related artifacts on postoperative magnetic resonance (MR) images of 17 patients who underwent spinal surgery.A phantom study evaluated the size of metallic artifacts, and a clinical study evaluated the quality of postoperative spinal MR images. Both 1.5-T studies used T1-weighted and T2-weighted fast spin echo sequences. The phantom study compared clip and artifact size for 10 clips. Artifacts were defined as signal voids surrounded by high signal amplitude that followed the clip shape. In the clinical study, 2 neurosurgeons assessed 22 images from 17 patients of the spinal cord, cauda equina, and paravertebral muscles adjacent to the nonpenetrating titanium clips, using 5-point scales.Mean metallic artifact sizes were 4.82 ± 0.16 mm (T1) and 4.66 ± 0.25 mm (T2; P0.001 vs. control). The former and latter were respectively 207% and 200% larger than the clip size. Both readers graded spinal cord and paravertebral muscles images as 3 or 4, indicating very good image quality regardless of clip-related artifacts, with excellent interobserver agreement (κ = 0.99 and 0.98, respectively).Metallic artifacts caused by nonpenetrating titanium clips were 200% larger than the actual clip but did not affect spinal cord and extradural tissue visualization. The use of these clips for closing the spinal dura mater does not alter postoperative radiologic evaluation quality.

The efficacy of the endoscopic transcortical transventricular approach (ETTA) for craniopharyngioma in the third ventricle with hydrocephalus has been reported focusing on its reduced invasiveness. On the other hand, suprasellar craniopharyngioma without ventriculomegaly is generally surgically managed by craniotomy or the endoscopic endonasal approach (EEA). Here, we report an elderly patient who received cyst fenestration and Ommaya reservoir placement in ETTA for recurrent suprasellar cystic craniopharyngioma without ventriculomegaly. The ETTA as a less invasive procedure is feasible in patients not only with intraventricular craniopharyngioma but also with suprasellar craniopharyngioma without hydrocephalus provided a navigational system is applied and the surgeon has ample experience with transcranial endoscopic procedures.

Background: Although glioblastoma has been shown to be able to disseminate widely in the intracranially after treatment with bevacizumab without any significant radiological findings, reports on such cases with subsequent autopsy findings are lacking. Case Description: A 36-year-old man presented with a general seizure and a mass of the right frontal lobe, which was diagnosed as diffuse astrocytoma (WHO Grade II). The patient underwent a total of four surgeries from 2005 to 2017. He showed tumor recurrence, progression, and malignant transformation to glioblastoma (GBM) (WHO Grade IV) despite repeated tumor resections, radiotherapy, and chemotherapies with temozolomide and carmustine wafers. Bevacizumab (10 mg/kg body weight) was started following the fourth surgery. After bevacizumab administration, the patient’s clinical condition improved to a Karnofsky performance status (KPS) score of 50–60, and he was stable for several months before finally deteriorating and passing away. Although sequential magnetic resonance imaging (MRI) showed shrinkage of the lesion and a reduction of edema, an autopsy showed widespread tumor invasion that was not revealed on MRI. Neoplastic foci were identified extensively in the cerebral cortex, basal ganglia, pituitary gland, cerebellum, and brainstem, imposing as gliomatosis cerebri. Conclusion: Imaging follow-up of malignant gliomas needs to be interpreted with caution as marked improvement in radiological response after bevacizumab treatment may not be indicating tumor regression. Despite the notable lack of evidence to increase overall survival in GBM patients with bevacizumab, the increase in progression-free survival and the observed relief of symptoms due to a decrease in edema should be considered relevant for patient management.

Background The endoscopic endonasal approach for the craniovertebral junction (CVJ), instead of the microscopic transoral approach, has been widely adopted and accepted, especially in resection of the odontoid process for basilar invagination. However, there is concern regarding insufficient resection of odontoid and surgical complications, including vessel injuries, because this is a historically immature procedure. Here, we report a surgical case of endoscopic endonasal odontoidectomy (EEO) in the hybrid operating room (hOR) for improvement of its safety and reliability. Case Description A 70-year-old man presented with a 2-month history of myelopathic gait disturbance and swallowing disturbance. Neuroimaging analysis indicated medulla oblongata compression associated with basilar invagination. The patient underwent EEO in the hOR after posterior instrumented fixation. With the hOR, the extent of bone resection and anatomic orientation were confirmed intraoperatively. Postoperative course was uneventful, and symptoms were improved after surgery. Conclusions The application of the hOR may make the EEO safe and precise for anterior decompression of the CVJ. To our knowledge, this is the first case report describing clinical experience of EEO in the hOR.

Objective Corkscrew (CS) electrodes are usually used for transcranial electrical stimulation (TES) in the intraoperative monitoring of motor evoked potentials (MEP). Direct cranial stimulation with peg-screw (PS) electrodes can elicit MEP. The present study investigated the difference in the initial threshold between PS and CS electrodes for intraoperative MEP monitoring. Methods We retrospectively analyzed TES-MEP monitoring for supratentorial surgery in 72 patients. Of these 72 patients, 44 were monitored with PS and CS electrodes (PS/CS group) and 28 were monitored with CS and CS electrodes (CS/CS group). TES was used to deliver electrical stimulation by a train of 4-pulse anodal constant current stimulation. The initial threshold in each electrode was checked and analyzed. Results In the PS/CS group, the initial threshold with the PS electrode was 38.3 ± 15.1 mA (mean ± standard deviation) on the affected side, and the initial threshold with the CS electrode was 51.4 ± 13.9 mA on the unaffected side. The initial threshold with the PS electrode was significantly lower than that with the CS electrode (P = 0.0001). In the CS/CS group, the initial threshold was 56.2 ± 16.5 mA on the affected side and 62.1 ± 18.6 mA on the unaffected side, with no statistically significant difference (P = 0.23). Conclusion The initial threshold to elicit MEP was significantly lower with the PS electrode than with the CS electrode. A PS electrode can be used as a feasible stimulation electrode for TES-MEP.