A Case of Suspected Radiation-Induced Meningioma That Developed 36 Years after Radiotherapy for a Suprasellar Tumor.

Recently, the improvements in the prognosis of childhood brain tumors have made it necessary to consider the risk of radiation-induced brain tumor development in long-term survivors. In this report, we describe a case of radiation-induced meningioma (RIM) treated surgically 36 years after radiotherapy. A 46-year-old woman, who underwent craniotomy for suprasellar germ cell tumor at 10 years of age with additional postoperative radiotherapy, was admitted to the emergency room with consciousness disturbance and right hemiplegia. One year earlier, magnetic resonance imaging (MRI) revealed a 1-cm diameter tumor in the left middle cranial fossa. This MRI showed an enlarged brain tumor in same lesion with clearly enhanced by gadolinium. A RIM located on a left sphenoid ridge with a fast growth rate was diagnosed, and the gross total removal was achieved by a left frontotemporal craniotomy. Histological diagnosis of atypical meningioma (World Health Organization grade II) was made. RIMs are frequently atypical, anaplastic meningiomas that have already been treated with radiotherapy, making additional postoperative radiotherapy difficult; the removal rate must be increased to achieve a good prognosis. In the case of long-term survivors after childhood radiotherapy, a strict follow-up with the occurrence of RIM in mind is necessary.

Small vestibular schwannoma presented with trigeminal neuralgia: illustrative case.

BACKGROUND: A vestibular schwannoma (VS) presenting with paroxysmal facial electric shock pain, that is, trigeminal neuralgia (TN), is relatively rare. Furthermore, TN is extremely rare in small VSs. OBSERVATIONS: Herein, the authors report the case of a 52-year-old woman with a complaint of right TN. Magnetic resonance (MR) imaging revealed a right VS of 12-mm diameter that compressed the trigeminal nerve. Although she did not report any hearing impairment, audiometry revealed decreased high-frequency range on the right side. The tumor was excised using the right retrosigmoid approach, and TN was confirmed to be caused by direct compression of the trigeminal nerve by the VS. Sufficient decompression of trigeminal nerve was done. The proximity of the trigeminal nerve root to the vestibular nerve root was the cause of TN. TN disappeared immediately after surgery, and there was no worsening of hearing impairment and facial paralysis. LESSONS: It is important to remember that TN may occur with direct tumor compression, even in small VSs. A preoperative 3-dimensional MR cisternogram/angiogram fusion image clearly showed direct tumor compression of the trigeminal nerve and the absence of responsible vessels, which was useful for surgical planning.

Unruptured aneurysm at bifurcation of super short middle cerebral artery mimicking duplicated middle cerebral artery aneurysm.

Background: Duplicated middle cerebral artery (DMCA) is a normal variation of the middle cerebral artery (MCA), and distinguishing DMCA from other arteries based only on the angiographical findings is sometimes difficult. Case Description: Preoperative angiography of a 60-year-old woman revealed two MCAs originating near the top of the right internal carotid artery and a 6-mm-sized aneurysm located between these two MCAs. The ipsilateral A1 segment of the anterior cerebral artery was not visualized due to hypoplasia. The patient was diagnosed with an unruptured aneurysm at the bifurcation between MCA and DMCA, preoperatively. However, during clipping surgery, the hypoplastic A1 segment was observed at approximately 2 mm proximal to the bifurcation of the MCA, indicating that these two MCAs were not "true" MCA and DMCA, but rather two normal MCA trunks bifurcated from the very short prebifurcation segment of M1. This difference in interpretation was due to the fact that the hypoplastic A1 was not visualized on preoperative examinations. The patient was discharged following the surgery without any neurological deficits. Conclusion: The distinction between DMCA and MCA trunks from the very short prebifurcation segment of MCA might be difficult, especially when the ipsilateral A1 segment is hypoplastic. Such an M1 with a length of 2-3 mm might be named super short M1. Thus, it is necessary to confirm the anatomy during aneurysm surgery.

In vivo goat brain model for neurosurgical training.

Background: Novice neurosurgeons require neurosurgical technique training, but the current method is demanding and time consuming. Therefore, it is crucial to perform training using an appropriate and informative method. In this report, we describe our attempts to provide training in neurosurgical techniques using goat in vivo brain model and to demonstrate the effectiveness of this model. Methods: Under general anesthesia, the surgery was performed on a male goat in the prone position. A midline liner skin incision was made in the scalp, six burr holes were drilled, a craniectomy was performed, and the dura was incised in an arcuate fashion. We attempted the interhemispheric approach and a retrosigmoid approach. Results: It was confirmed that common neurosurgical approaches are achievable in this model. Furthermore, anatomical structures such as nerves and blood vessels were similar to those of humans. Moreover, the goat brain was similar in color and texture to that of humans. Conclusion: Unlike a cadaver brain, in vivo brain requires hemostasis and careful dissection, which provides the surgeons a realistic experience of actual neurosurgery.

Intermediate nerve neuralgia developed during hemifacial spasm follow-up: illustrative case.

BACKGROUND: Intermediate nerve neuralgia (INN) is a rare condition believed to be caused by vascular compression, with external auditory canal pain as the chief symptom. The authors reported a rare case of a 78-year-old woman who developed INN during follow-up for hemifacial spasm (HFS). OBSERVATIONS: The patient had been receiving Botox treatment for right HFS for 20 years when she developed paroxysmal electric shock pain in the right external auditory canal and tinnitus induced by opening her mouth. A three-dimensional magnetic resonance fusion image showed the cisternal portion of the facial-vestibulocochlear nerve complex to be compressed by the meatal loop of the anterior inferior cerebellar artery (AICA), which was pressed against by the posterior inferior cerebellar artery. The authors diagnosed INN, and microvascular decompression (MVD) was performed. Surgical findings were consistent with preoperative neuroimaging. In addition, the proximal portion of the meatal loop of the AICA had passed between the facial and vestibulocochlear nerves, compressing both. The AICA was moved and the nerve completely decompressed. All symptoms improved immediately following surgery. LESSONS: When INN occurs during HFS follow-up, aggressive MVD should be considered based on detailed neuroimaging. This treatment is a very effective single-stage cure for INN, HFS, and vestibulocochlear symptoms.

A complete thrombotic large aneurysm at the nonbranching segment of the distal anterior cerebral artery mimicking a cavernous malformation: illustrative case.

BACKGROUND: Thrombotic aneurysms at the nonbranching segment of the distal anterior cerebral artery (ACA) are extremely rare and difficult to differentiate from cavernous malformations by radiographic features alone. OBSERVATIONS: Computed tomography and magnetic resonance imaging of a 30-year-old female patient with a chronic headache complaint revealed a 22-mm frontal lobe mass. The mass showed heterogeneous mixed intensity and hemosiderin deposits on magnetic resonance images. It was not visualized by conventional angiography, indicating that the mass and ACA/other vessels were not connected. The patient was preoperatively diagnosed with a cavernous malformation. However, during resection, the mass surface was white and smooth, different from a cavernous malformation. Although the mass was adherent to the pericallosal artery branch, no luminal continuity was observed. After detachment, the mass was completely resected. Pathological and immunohistochemical findings indicated a vessel wall and interior thrombus. The patient was rediagnosed with a thrombotic aneurysm at the distal ACA nonbranching segment and discharged 10 days postsurgery without neurological deficits. LESSONS: Because radiographic findings of thrombotic aneurysm and cavernous malformation are similar, mass lesions in contact with major arteries should be differentiated as thrombotic aneurysms, even when the artery lumen appears disconnected from the mass.

Prosthesis Used in Microvascular Decompressions: A Multicenter Survey in Japan Focusing on Adverse Events.

OBJECTIVE: To investigate the characteristics of materials used as prostheses for microvascular decompression surgery (MVDs) in Japan and their possible adverse events (AEs) to determine preferable materials for MVDs. METHODS: A questionnaire was sent to all members of the Japanese Society for MVDs, and answers were obtained from 59 institutions. RESULTS: Among a total of 2789 MVDs, 1088 operations for trigeminal neuralgia, 1670 for hemifacial spasm, and 31 others, including 117 reoperations, were performed between April 2011 and March 2014. Nonabsorbable material was used in 96.5% of MVDs, including polytetrafluoroethylene (PTFE) (80.5%), polyurethane (11.9%), expanded PTFE (2.1%), and silk thread (1.47%). The use of absorbable materials, including fibrin glue (87.5%), cellulose (13.5%), gelatin (4,77%), and collagen (1.76%), was reported. The major combinations were PTFE with fibrin glue (58.7%) followed by PTFE alone (7.60%). Eighty-eight AEs in 85 (3.2%) cases were reported among 2672 first operations. AEs included 51 central nervous system dysfunctions, 15 wound infections/dehiscence, and 10 others, which were presumed to be related to the intraoperative procedure. Among relatively high-, moderate-, and low-volume centers, there were no significant differences in the frequency of AEs (P = 0.077). Tissue-prosthesis adhesion and/or granuloma formation were reported in 13 cases of 117 reoperations. The incidence of adhesion-related recurrence was 11.1% of all reoperations. CONCLUSIONS: The number of AEs was quite low in this survey, and intradural use of any prosthesis reported in this paper might be justified; however, further development of easily handled and less-adhesive prosthesis materials is awaited.

Predictive Factors of Antiparkinsonian Drug Reduction after Subthalamic Stimulation for Parkinson's Disease.

Subthalamic nucleus deep brain stimulation (STN-DBS) improves motor symptoms in individuals with advanced Parkinson's disease (PD) and enables physicians to reduce doses of antiparkinsonian drugs. We investigated possible predictive factors for the successful reduction of antiparkinsonian drug dosage after STN-DBS. We evaluated 33 PD patients who underwent bilateral STN-DBS. We assessed rates of reduction of the levodopa-equivalent daily dose (LEDD) and levodopa daily dose (LDD) by comparing drug doses before vs. 6-months post-surgery. We used correlation coefficients to measure the strength of the relationships between LEDD and LDD reduction rates and preoperative factors including age, disease duration, preoperative LEDD and LDD, unified Parkinson's Disease Rating Scale part-II and -III, levodopa response rate, Mini-Mental State Examination score, dyskinesia score, Hamilton Rating Scale for depression, and the number of non-motor symptoms. The average LEDD and LDD reduction rates were 61.0% and 70.4%, respectively. Of the variables assessed, only the number of psychiatric/cognitive symptoms was significantly correlated with the LEDD reduction rate. No other preoperative factors were correlated with the LEDD or LDD reduction rate. A wide range of preoperative psychiatric and cognitive symptoms may predict the successful reduction of antiparkinsonian drugs after STN-DBS.

Extensive spinal epidural immature teratoma in an infant: case report.

Here, the authors present an extremely rare case of an extensive spinal epidural teratoma (SET) in an infant and provide a review of the cases in the literature. In this report, the authors focused on the clinical manifestation and management of extensive SET. A 64-day-old girl presented with severe dyspnea and paraparesis caused by a large thoracic mass. Imaging studies revealed that the mass originated from the epidural space of the thoracic spine and extended from C7 to L1. The tumor extended bilaterally through the intervertebral foramina and formed a large posterior mediastinal mass. The tumor was partially resected via laminotomy after an emergency thoracotomy. The remnant grade I immature teratoma grew rapidly. After a re-laminotomy and bilateral thoracotomy, the residual tumor stopped growing. However, the patient's paraparesis improved very little, and her scoliosis progressed gradually. Therefore, SET should be included in the differential diagnosis when an infant patient with paraparesis of the lower extremities is encountered. Timely diagnosis, aggressive treatment, and close monitoring are of critical importance to successful recovery in such patients.

[Surgical Technique for Lumbar Spinal Extraforaminal Schwannoma].

INTRODUCTION: Spinal neurinomas are frequently observed in the cauda equina, particularly within the dura mater. However, extraforaminal schwannomas(EFS), which are neither intradural nor dumbbell type, are relatively rare; hence, different surgical procedures have been employed. Here, we report 12 cases of lumbar EFS with total resection that were safely performed. METHODS AND SUBJECTS: This study was comprised of 12 patients with lumbar EFS(excluding those with neurofibromas)who were previously treated at our hospital. Using the Wiltse paraspinal approach, we inserted the microscope until it reached the tumor surface. After confirming the tumor surface, we inserted a scalpel to make an incision in a portion of the outer capsule. Then, we confirmed that the surfaces of the outer capsule and the tumor within the capsule could be dissected. Next, a thread was attached to the outer capsule and pulled upwards so that there was enough space to perform the required procedures within the capsule. Using a CUSA®, we removed the intracapsular tumor. After its removal, the outer capsule was treated carefully to ensure that the origin nerve was not damaged. RESULTS: In all cases, we successfully performed a total removal of the intracapsular tumor;in the mean postoperative observation period of 8 years, no recurrence was observed. Although temporary paralysis was observed in three patients, this improved over time. CONCLUSION: We report our experience with a surgical technique that ensured the safe removal of lumbar EFS. Satisfactory results were achieved, with no recurrences observed during the mean 8-year postoperative observation period.

Differences in the Genotype Frequency of the RNF213 Variant in Patients with Familial Moyamoya Disease in Kyushu, Japan.

The p.R4810K (rs11273543, c.14429G > A) variant of the RNF213 gene is associated with increased risk of Moyamoya disease (MMD), which is an idiopathic progressive intracranial vascular steno-occlusive disease, in Asian populations. Numerous variant association studies for this MMD variant have been performed in Japan to date. Since another genetic study that utilized approximately 140,000 single nucleotide polymor (SNPs) has indicated that there still are genetic differences among mainland Japanese, there is a possibility that the variant distribution in patients with MMD and normal individuals varies between different Japanese regions. Additionally, the majority of variant association studies have used Sanger sequencing, which is labor-intensive, time-consuming, and costly. In this study, we analyzed the frequency of the variant genotype in patients with MMD and normal individuals in Kyushu using pyrosequencing, which is an accurate, cost-effective, and automated method. We found differences in the genotype frequencies in familial patients from Kyushu and normal populations in Tohoku compared with west Japan, which suggested that there were differences in the frequency of the variant among different regions in Japan.

[A Rare Case of Cerebellar Hemangioblastoma Causing Taste Disorder].

Taste(gustation)is one of the five senses, and comprises the types: sweet, bitter, salty, sour, and umami. Taste disorders, such as dysgeusia and parageusia, are classified into 2 types: those with peripheral origin and those with central origin. The peripheral origin-type taste disorder is caused by zinc deficiency, mouth dryness, a side effect of radiotherapy or complication of systemic diseases such as, diabetes, hepatopathy, and nephropathy. The central origin-type taste disorder is reported to be caused due to demyelinating disease, pontine hemorrhage, pontine infarction, and thalamic infarction; it is very rarely caused by a brain tumor. We surgically treated a 69-year-old man with cerebellar hemangioblastoma who had developed taste disorder. The tumor compressed the solitary nucleus, which includes the taste tract in the central nervous system. On removal of the tumor, the taste disorder gradually improved.

Brain metastasis from primary peritoneal carcinoma: Case report and literature review.

Here, we describe a patient with primary peritoneal carcinoma (PPC) who developed a late, solitary brain metastasis. It is a case of a 68-year-old female presented with a 1-month history of progressive gait disturbance who had undergone a surgical resection of PPC five years prior, followed by adjuvant chemotherapy. An MRI revealed a 4.6cm mass lesion in her right cerebellum. The patient underwent total removal of the tumour. The histopathology was consistent with a brain metastasis due to PPC. This condition is a rare malignancy of peritoneum, and only six cases of brain metastasis have been reported in PPC patients to date. Due to the prolongation of survival resulting from advanced chemotherapy for PPC, more patients will live long enough to develop brain metastases.

Outcome of microvascular decompression for hemifacial spasm associated with the vertebral artery.

We retrospectively compared the outcome of microvascular decompression (MVD) for hemifacial spasm (HFS) associated with the vertebral artery (VA) with that of MVD for HFS unrelated to the VA. Between April 2008 and April 2015, 22 patients with VA-associated HFS underwent MVD at our institution. The median follow-up period was 28 months (range, 12-90 months). Results were classified as excellent in 19 patients (86 %), good in one (5 %), fair in one (5 %), and poor in one (5 %). Immediate complications developed in five patients (23 %), and one of these complications (5 %) was permanent. The surgical outcome of MVD for VA-associated HFS was similar to that of MVD for HFS unrelated to the VA; however, the incidence of complications was significantly more frequent in patients whose VA compressed the more proximal portion of the facial nerve root exit zone from the caudal side at the pontomedullary sulcus. We conclude that preoperative evaluation of VA compression patterns is important to predict the difficulty of the planned MVD procedure.

Carotid artery stenosis with a high-intensity signal plaque on time-of-flight magnetic resonance angiography and association with evidence of intraplaque hypoxia.

OBJECTIVE Hypoxia induces angiogenesis and plays a major role in the progression of carotid plaques. During carotid intervention, plaques with high-intensity signals on time-of-flight (TOF) magnetic resonance angiography (MRA) often cause ischemic stroke and embolic complications. However, the role of intraplaque hypoxia before carotid endarterectomy (CEA) and carotid artery stenting is not presently understood. In this study the authors aimed to investigate the relationship between intraplaque hypoxia and MRA findings. METHODS Nineteen consecutive patients with 20 carotid artery stenoses who underwent CEA at Saga University Hospital between August 2008 and December 2014 were enrolled in the study. The expressions of hypoxia-inducible transcription factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) were analyzed by immunohistochemical analysis. In addition, the relationship between the findings on TOF MRA and pathology for the carotid plaques was analyzed. RESULTS High-intensity plaques on TOF MRA showed higher expression levels of HIF-1α (p = 0.015) and VEGF (p = 0.007) compared with isointensity plaques. The rate of intraplaque hemorrhage (IPH) on TOF MRA was also significantly higher in the high-intensity plaques than in the isointensity plaques (p = 0.024). Finally, the mean number of neovessels was significantly higher in those without plaque hemorrhage than in those with plaque hemorrhage (p = 0.010). CONCLUSIONS Plaques with high-intensity signals on TOF MRA were associated with IPH and evidence of intraplaque hypoxia. This fact may represent an opportunity to establish novel therapeutic agents targeting intraplaque hypoxia.

Typical Symptoms of Normal-Pressure Hydrocephalus Caused by Choroid Plexus Papilloma in the Cerebellopontine Angle.

BACKGROUND: Choroid plexus papillomas (CPPs) are rare benign intracranial tumors. We report a rare case of CPP manifesting with typical symptoms of normal-pressure hydrocephalus rather than obstructive hydrocephalus. CASE DESCRIPTION: A 45-year-old woman presented with a 6-year history of headache and typical symptoms of normal-pressure hydrocephalus, including gait disturbance, urinary incontinence, and cognitive dysfunction, in addition to the more common symptoms of CPP, such as lower cranial nerve dysfunctions and ataxia. The CPP arose from the right lateral recess of the fourth ventricle and extended to the cerebellopontine angle. Magnetic resonance imaging did not show any radiographic evidence of obstruction of aqueduct, foramen of Magendie, or foramen of Luschka on the contralateral side. We speculated that hydrocephalus was associated with cerebrospinal fluid overproduction by the CPP originating from the choroid plexus of the lateral recess and extending laterally into the cerebellomedullary fissure (CMF). Surgical excision was performed with a trans-CMF approach. The symptoms of normal-pressure hydrocephalus disappeared. In addition to improved clinical symptoms, radiographic findings showed mitigation of ventricular dilatation. CONCLUSIONS: The hydrocephalus was of a communicating type and caused by CSF overproduction. The lateral route of the trans-CMF approach is useful for the dissection of tumors that extend into the unilateral cerebellomedullary cistern through the CMF. This approach not only enables sufficient exposure for resection but also avoids damage to the surrounding structures.

[Two Cases of Ruptured Cerebral Aneurysm Complicated with Delayed Coil Protrusion after Coil Embolization].

We report two cases of delayed coil protrusion after coil embolization for ruptured cerebral aneurysms. Case 1:An 82-year-old woman with a subarachnoid hemorrhage due to a ruptured small anterior communicating artery aneurysm underwent successful coil embolization. Eighteen days after the procedure, coil protrusion from the aneurysm into the right anterior cerebral artery was observed without any symptoms. Further coil protrusion did not develop after 28 days. Case 2:A 78-year-old woman with a subarachnoid hemorrhage due to a ruptured small left middle cerebral artery aneurysm underwent successful coil embolization. Twenty days after the procedure, coil protrusion from the aneurysm into the left middle cerebral artery was observed, with a transient ischemic attack. Further coil protrusion did not develop. Both patients recovered with antithrombotic treatment. Even though delayed coil protrusion after coil embolization is rare, it should be recognized as a long-term complication of coil embolization for cerebral aneurysms.

Outcome of microvascular decompression for trigeminal neuralgia treated with the stitched sling retraction technique.

The purpose of this retrospective study was to describe and evaluate the long-term outcome of microvascular decompression (MVD) with the stitched sling retraction technique for treating trigeminal neuralgia (TN). Between January 2007 and December 2012, 50 patients with idiopathic TN underwent MVD using the stitched sling retraction technique at our institution. The median follow-up period was 5.2 years (range, 1.8-6.8 years). Using Kaplan-Meier analysis, the rates of complete pain relief without medications were 88% at 1 year and 83% at 5 years. Recurrence was noted in two patients, and one patient was re-treated using a complementary procedure for pain relief. Although transient complications were observed in seven patients, no permanent neurological deficit was observed. We conclude that the stitched sling retraction technique is a safe and effective treatment for TN and maintains substantial pain relief and low recurrence rates over a long period of time.