Mitsuhiro Anan

A rosette-forming glioneuronal tumor of the spinal cord: the first case of a rosette-forming glioneuronal tumor originating from the spinal cord.

Rosette-forming glioneuronal tumors of the fourth ventricle are rare brain tumors, and only 19 such lesions have been previously reported. This report presents the first case of a rosette-forming glioneuronal tumors arising from the spinal cord. A 44-year-old woman presented with a 15-year history of dissociated sensory disturbance of the lower extremities that gradually spread through her upper extremities. She also experienced continuing motor disturbance. Magnetic resonance imaging demonstrated a mass in the cervicothoracic spinal cord that suggested an intramedullary spinal tumor. A total gross resection of the tumor was performed. As is typical of rosette-forming glioneuronal tumors of the fourth ventricle, this spinal cord example manifested neurocytic and astrocytic components. Neurocytic rosettes were detected in the neurocytic component, and the center of rosettes showed positive immunostaining for synaptophysin. The astrocytic component showed characteristic features of a pilocytic astrocytoma, as is often the case in the fourth ventricle examples.

Postoperative adjuvant treatment for pineal parenchymal tumour of intermediate differentiation

Pineal parenchymal tumour of intermediate differentiation (PPTID) in adults is rare and a treatment strategy for this condition has not yet been established. We present a case of an elderly patient treated with postoperative adjuvant therapy using radio- and chemotherapy. This 60-year-old man presented with a 3-month history of memory disturbance, gait instability and double vision. Computed tomography and magnetic resonance imaging demonstrated a mass in the pineal region that suggested a malignant tumour. Partial removal of the tumour was undertaken via the right occipital transtentorial approach. The histological diagnosis was PPTID. Postoperative radio- and chemotherapy were administered, with a good response. Little is known about the clinical behaviour of PPTID in adults. Our treatment plan indicates one effective option for the management of such tumours.

Neuroprotective effects of edaravone, a free radical scavenger, on the rat hippocampus after pilocarpine-induced status epilepticus.

PURPOSE Edaravone (MCI-186) is a newly developed antioxidative radical scavenger for the treatment of acute cerebral infarction, exerting neuroprotective effects against ischemic insult. The neuroprotective effects of edaravone on pilocarpine-induced seizures in rats were investigated. METHODS Rats were treated intraperitoneally with saline or edaravone (1-30 mg/kg), applied 30 min before pilocarpine hydrochloride (330 mg/kg). The onset of status epilepticus (SE) and mortality were recorded for a period of at least 3 days. The cell loss and immunoreactivities of nitric oxide synthase (NOS) in the hippocampus from control and the day 3 rats after SE, treated with saline or edaravone, were evaluated. RESULTS Edaravone (1mg/kg) significantly prevented cell loss in the hippocampus after SE while easier inducing SE. The higher dose of drug could not induce SE significantly but tended to increase the rate of mortality. Inducible NOS (iNOS) expression was significantly decreased in the hippocampus from day 3 rats treated with 1mg/kg edaravone, compared with saline group, while neuronal NOS (nNOS) and iNOS significantly increased in the hippocampus treated with saline, compared with control group. Significant alteration of endothelial NOS (eNOS) expression in the hippocampus among control group, saline group, and edaravone group was not shown. CONCLUSIONS Edaravone may act as a neuroprotector for the hippocampus after SE by reducing at least iNOS although the low dose of drug easier induces SE because of preventing an endogenous antiepileptic effect of NO.

Induced angiogenesis under cerebral ischemia by cyclooxygenase 2 and hypoxia-inducible factor naked DNA in a rat indirect-bypass model.

We recently reported that hypoxic stress induces the expression of HIF-1alpha, HIF-2alpha, cyclooxygenases-2 (COX-2) and VEGF in vivo. In this study, we investigated whether HIF-1alpha, HIF-2alpha, or COX-2 naked DNA induced angiogenesis in a cerebral ischemic model in vivo. We utilized a rat encephalo-myo-synangiosis (EMS) model and inoculated naked DNA into the brain surface. We analyzed whether DNA induced angiogenic factors and neovascularization. New blood vessel formation was detected by anti-Factor VIII staining. A histological section treated with HIF-2alpha or COX-2 DNA showed an increased expression of VEGF with angiogenesis, in comparison to the control DNA. The HIF-1alpha, HIF-2alpha, and COX-2 are able to promote significant angiogenesis development. These results suggest the feasibility of a novel approach for therapeutic angiogenesis of cerebral ischemia in which neovascularization may be indirectly achieved using a transcriptional and cytokines regulatory strategy.

Surgical technique for anterior skull base reconstruction using hydroxyapatite cement and titanium mesh

Dear Sirs: We have previously reported a surgical technique for anterior skull base reconstruction using an overlapping free bone graft with galea–pericranium [1]. This method prevented CSF leakage and sequestrum formation. However, in patients with tumour infiltration into the inner table of skull, it is difficult to use this method for skull base repair. A 52-year-old man was admitted because of small cell carcinoma. Magnetic resonance images (MRI) revealed the extension of a tumour to the medial orbits, frontal sinus and frontal lobe (Fig. 1a). Computed tomography (CT) demonstrated the presence of a skull base defect and the destruction of the inner table of the frontal sinus. After the total removal of the tumour, a 6×5-cm bone defect was observed. The reconstruction of the skull base was performed as follows: the skull base defect was covered with 0.3-mm-thick titanium mesh (Stryker, Tokyo, Japan) (Fig. 1d) and hydroxyapatite cement (HAC; Kobayashi Medical, Osaka, Japan) (Fig. 1e); then, both were covered with a vascularised galeal–pericranial flap. The dural laceration of the frontal base was repaired with a galea, and thereafter the edge of the galeal–pericranial flap was sutured to the normal dural margin. All layers and dual flaps were fixed with fibrin glue. The free frontal bone flap, in which tumour invasion was observed, was autoclaved and used for cranioplasty. The patient did not show any surgical complications, such as CSF leakage or meningitis. Postoperative MRI demonstrated complete remission and skull base repair (Fig. 1b). Sagittal reconstruction of a CTshowed skull base reconstruction and more than 60% of the skull base was covered with titanium mesh and HAC (Fig. 1c). Since its introduction in 1996, injectable HAC has been used successfully in many fields. Durham et al. [2] demonstrated a technique in which they use HAC, reinforced with tantalum mesh and titanium miniplates, for the repair of large (>25 cm) cranial defects. On the other hand, Kitano and Taneda [3] showed a technique of HAC for cranial base reconstruction after transsphenoidal surgery. However, they used it for relatively small bone defects. It is difficult to use this method for large cranial base reconstruction. Therefore, we used thin transformable titanium mesh, as a supporting and reinforcing material for HAC. Although the number of patients on whom we have performed this technique is low, none of the patients had any complications related to the surgery. This skull base reconstruction procedure is therefore considered to be a simple and useful technique to prevent CSF leakage and infection. Further experiments are therefore required to determine whether this procedure does indeed help to reduce the risk of complications. Acta Neurochir (2009) 151:1337–1338 DOI 10.1007/s00701-009-0392-4

Superficial Temporal Artery-To-Middle Cerebral Artery Anastomosis with Encephalo-Duro-Myo-Synangiosis as a Modified Operative Procedure for Moyamoya Disease

BACKGROUND Various types of revascularization surgery have been performed for moyamoya disease. Although the efficacies of these operations are well recognized, the optimal operative procedure remains undecided. In this report, we describe our modified surgical revascularization procedure for moyamoya disease and retrospectively analyze the results of such surgeries on six sides in six adult patients. METHODS Our operative procedure, combining direct and indirect bypasses, is a superficial temporal artery to middle cerebral artery anastomosis with encephalo-duro-myo-synangiosis. The encephalo-duro-myo-synangiosis is an indirect bypass combining the encephalo-duro- and encephalo-myo-synangioses. This operative procedure has been used routinely in adult patients since 2002. RESULTS Perioperative complications were noted in one of the six operations. This complication was transient and no attributive lesions were detected on CT or MRI. Revascularization was seen in cerebral blood flow studies in all patients, and the clinical outcomes were excellent or good. Effective neovascularization through the grafts was observed in all patients in follow-up angiographies. CONCLUSIONS This operative procedure provides needed revascularization and prevents ischemic deficits. This modified procedure is useful for responding to subsequent additional ischemia in the area of the anterior cerebral artery and should be considered one of the optimal procedures for treating moyamoya disease.

Third nerve palsy caused by compression of the posterior communicating artery aneurysm does not depend on the size of the aneurysm, but on the distance between the ICA and the anterior–posterior clinoid process

OBJECTIVE Third nerve palsy (TNP) caused by a posterior communicating artery (PCoA) aneurysm is a well-known symptom of the condition, but the characteristics of unruptured PCoA aneurysm-associated third nerve palsy have not been fully evaluated. The aim of this study was to analyze the anatomical features of PCoA aneurysms that caused TNP from the viewpoint of the relationship between the ICA and the skull base. METHODS Forty-eight unruptured PCoA aneurysms were treated surgically between January 2008 and September 2013. The characteristics of the aneurysms were evaluated. RESULTS Thirteen of the 48 patients (27%) had a history of TNP. The distance between the ICA and the anterior-posterior clinoid process (ICA-APC distance) was significantly shorter in the TNP group (p<0.01), but the maximum size of the aneurysms was not (p=0.534). CONCLUSION Relatively small unruptured PCoA aneurysms can cause third nerve palsy if the ICA runs close to the skull base.

Induction of collateral circulation by hypoxia-inducible factor 1α decreased cerebral infarction in the rat

Abstract Background: We recently reported that hypoxia-inducible factor 1α (HIF-1α), HIF-2α and cyclooxygenase 2 naked DNA induced angiogenesis in a rat indirect bypass model. In this work, we investigated whether the collateral circulation induced by HIF-1α DNA affected the cerebral infarction. Methods: We utilized a rat encephalomyosynangiosis (EMS) model and inoculated HIF-1α DNA onto the brain surface. These treatments were performed before the cerebral infarction occurred. We thereafter performed middle cerebral artery occlusion on the fifth or tenth day after EMS. Results: A histological section treated with HIF-1α DNA for 10 days showed a well-developed collateral circulation (p<0.05) and a reduction in the infarction volume in comparison to the control DNA (p<0.01). Conclusion: These results suggest the feasibility of a novel approach for the treatment of cerebral ischemia via the development of therapeutic collateral circulation, in which neovascularization may be indirectly achieved using a transcriptional regulatory strategy.

Navigated Brain Stimulation for Preoperative Anatomic and Functional Identification of Impaired Motor Cortex in a Patient With Meningioma

Anatomic and functional organization of the motor cortex in a left falx meningioma case with a large extent of paper-thin cortex was evaluated using navigated brain stimulation (NBS) with transcranial magnetic stimulation (TMS). A 51-year-old woman had a history of gait disturbance for 6 months. Magnetic resonance imaging of the brain demonstrated a left 5-cm homogeneous tumor with caudally compressed motor cortex. A frameless image-guided neuronavigational device was used for NBS to determine the position of the actual sites of the stimulation coils relative to the cortical surface. Descending corticospinal hand motor pathways in the motor cortices were evaluated by the NBS system with TMS in normal subjects (n=10) and in this meningioma case. Motor-evoked potentials were simultaneously recorded from the first dorsal interosseous (FDI) and biceps brachii (BB) muscles preoperatively and intraoperatively with NBS system. NBS with TMS in the patient showed fast-conducting FDI projections from the substantially deviated primary motor cortex (24 mm medially in comparison with healthy controls, with medio-lateral direction, 19 mm depth from the scalp), whereas BB projections were identified at 12 mm caudally to the controls (latero-medial direction, 32 mm depth from the scalp). Intraoperative findings confirmed localization of a thin functioning FDI motor cortex over the tumor top and proximal BB motor cortex compressed beneath the tumor. These observations could not be made by magnetic resonance images alone. Preoperative precise motor cortical mapping using NBS with TMS has the potential to explore anatomic shift and physiologic organization and plastic changes in the human motor system and to establish the degree of remaining functionality in the motor cortex after long-term physical compression and deviation in tumors such as meningioma without implanting electrodes.

A hemispherotomy for intractable startle epilepsy characterized by infantile hemiplegia and drop attacks

Startle epilepsy is provoked by unexpected sensory stimuli, mainly auditory, and reveals subsequent tonic posturing of the limbs. We present a case of intractable startle epilepsy with infantile hemiplegia and discuss the indications for a hemispherotomy.