[Interactive Virtual Simulation with Haptics for Neurosurgery].

We established a unique pre-surgical simulation method by applying interactive virtual simulation(IVS)using multi-fusion three-dimensional imaging data, presenting high-quality visualization of microsurgical anatomies. Our IVS provided a realistic environment for imitating surgical manipulations, such as dissecting bones, retracting brain tissues, and removing tumors, with tactile and kinesthetic sensations delivered through a specific haptic device. The great advantage of our IVS was in deciding the most appropriate craniotomy and bone resection to create the optimal surgical window and obtain the best working space with a thorough understanding of the lesion-bone relationship. Particularly for skull-base tumors, tailoring the procedures to individual patients for craniotomy and bone resection was sufficiently achieved using our IVS. In cases of large skull base meningiomas, our IVS was also helpful preoperatively regarding tumors, as several compartments were achievable in every potentially usable surgical direction. Additionally, the non-risky realistic microsurgical environments of the IVS provided improvement in the microsurgical senses and skills of young trainees through the repetition of surgical tasks. Finally, our presurgical IVS simulation method provided a realistic environment for practicing microsurgical procedures virtually and enabled us to ascertain the complex microsurgical anatomy, determine optimal surgical strategies, and efficiently educate neurosurgical trainees.

Missense mutation of NRAS is associated with malignant progression in neurocutaneous melanosis.

Neurocutaneous melanosis (NCM) is a rare congenital neurocutaneous syndrome characterized by congenital melanocytic nevus of skin and abnormal proliferation of leptomeningeal melanocytes. Early acquisition of post-zygotic somatic mutations has been postulated to underlie the pathogenesis of NCM. The pathogenesis of NCM remains to be fully elucidated, and treatment options have not been established. Here, we report for the first time, multiregional genomic analyses in a 3-year-old autopsied girl with leptomeningeal melanomatosis associated with NCM, in which a ventriculo-peritoneal (VP) shunt was inserted for the treatment of hydrocephalus. The patient expired six months after the onset due to respiratory failure caused by abdominal dissemination via VP shunt. We performed multiregional exome sequencing to identify genomic differences among brain and abdominal tumors, nevus, and normal tissues. A total of 87 somatic mutations were found in 71 genes, with a significantly large number of gene mutations found in the tumor site. The genetic alterations detected in the nevus were only few and not shared with other sites. Three mutations, namely GNAQ R183Q, S1PR3 G89S and NRAS G12V, considered pathogenic, were found, although S1PR3 mutations have not been previously reported in melanocytic tumors. GNAQ and S1PR3 mutations were shared in both tumor and normal sites. Moreover, the mutant allele frequencies of the two mutations were markedly higher in tumor sites than in normal sites, with copy-neutral loss-of-heterozygosity (CN-LOH) occurring in tumor. NRAS mutation was found only in the abdominal tumor and was thought to be responsible for malignant progression in the present case. Multiregional comprehensive genetic analysis may lead to discovering novel driver mutations associated with tumorigenesis and targeted therapy.

Reliable detection of genetic alterations in cyst fluid DNA for the diagnosis of brain tumors.

PURPOSE: Liquid biopsy of cyst fluid in brain tumors has not been extensively studied to date. The present study was performed to see whether diagnostic genetic alterations found in brain tumor tissue DNA could also be detected in cell-free DNA (cfDNA) of cyst fluid in cystic brain tumors. METHODS: Cyst fluid was obtained from 22 patients undergoing surgery for a cystic brain tumor with confirmed genetic alterations in tumor DNA. Pathological diagnoses based on WHO 2021 classification and diagnostic alterations in the tumor DNA, such as IDH1 R132H and TERT promoter mutation for oligodendrogliomas, were detected by Sanger sequencing. The same alterations were analyzed by both droplet digital PCR (ddPCR) and Sanger sequencing in cyst fluid cfDNA. Additionally, multiplex ligation-dependent probe amplification (MLPA) assays were performed to assess 1p/19q status, presence of CDKN2A loss, PTEN loss and EGFR amplification, to assess whether differentiating between astrocytomas and oligodendrogliomas and grading is possible from cyst fluid cfDNA. RESULTS: Twenty-five genetic alterations were found in 22 tumor samples. All (100%) alterations were detected in cyst fluid cfDNA by ddPCR. Twenty of the 25 (80%) alterations were also detected by Sanger sequencing of cyst fluid cfDNA. Variant allele frequency (VAF) in cyst fluid cfDNA was comparable to that of tumor DNA (R = 0.62, Pearson's correlation). MLPA was feasible in 11 out of 17 (65%) diffuse gliomas, with close correlation of results between tumor DNA and cyst fluid cfDNA. CONCLUSION: Cell-free DNA obtained from cyst fluid in cystic brain tumors is a reliable alternative to tumor DNA when diagnosing brain tumors.

Preoperative interactive virtual simulation applying three-dimensional multifusion images using a haptic device for lumbosacral lipoma.

PURPOSE: Untethering surgery for lumbosacral lipoma is a preventive procedure, and avoidance of complications and good long-term outcomes are required. We introduced presurgical interactive virtual simulation (IVS) applying three-dimensional multifusion images using a haptic device aimed at improving operative outcomes. METHODS: Fourteen patients with newly diagnosed lumbosacral lipoma were recruited and underwent preoperative IVS. The median age at surgery was 8 months. A three-dimensional image analysis system was used to extract and fuse structures necessary for surgery, such as the lipoma, spinal cord and skin, from CT and MRI, and create three-dimensional multifusion images. The created images were individually converted to standard triangulated language format and loaded onto a workstation (Geomagic freeform™) that could be freely transformed, and the laminectomy range and lipoma extraction procedure were examined. Presurgical IVS was performed, and the actual surgery was performed. RESULTS: The disease types were dorsal, caudal, lipomyelomeningocele, transitional, and filum in 5, 5, 2, 1, and 1 patients, respectively. The surgical procedure and extent of the laminectomy were as planned for all patients. Resection of the lipomas tended to be less than expected preoperatively because of positive reactions on intraoperative monitoring. No postoperative complications were observed. The median postoperative follow-up period was 29 months, and there were no reoperations during the observation period. CONCLUSIONS: Although there are various types of lumbosacral lipoma, surgery can be safely performed by performing presurgical IVS. The short-term course is good; however, long-term follow-up is necessary for the appearance of neurological symptoms associated with growth and re-tethering.

Preoperative three-dimensional multifusion imaging aiding successful microvascular decompression of a cerebellopontine angle lipoma: associated hemifacial spasm. Illustrative case.

BACKGROUND: Cerebellopontine angle (CPA) lipoma-associated hemifacial spasm (HFS) is rare. As the removal of CPA lipomas has a high risk of worsening the neurological symptoms, surgical exploration is warranted only in selected patients. Preoperative identification of the lipoma affected site of the facial nerve, and offending artery are crucial for patient selection and successful microvascular decompression (MVD). OBSERVATIONS: Presurgical simulation using three-dimensional (3D) multifusion imaging showed a tiny CPA lipoma wedged between the facial and auditory nerves, as well as an affected facial nerve by the anterior inferior cerebellar artery (AICA) at the cisternal segment. Although a recurrent perforating artery from the AICA anchored the AICA to the lipoma, successful MVD was achieved without lipoma removal. LESSONS: The presurgical simulation using 3D multifusion imaging could identify the CPA lipoma, affected site of the facial nerve, and offending artery. It was helpful for patient selection and successful MVD.

Elucidating the multiple genetic alterations involved in the malignant transformation of a KRAS mutant neurenteric cyst. A case report.

Neurenteric cyst (NC) shows benign histopathology and rarely demonstrate malignant transformation. We herein describe a case of NC that exhibited malignant transformation. A 65-year-old female presented with gait disturbance due to compression by a cystic mass on the dorsal surface of the medulla oblongata. Partial resection was performed twice, leading to improvement of her symptoms. Two years after the second surgery, gadolinium-perfused T1-weighted magnetic resonance imaging revealed an invasive lesion with contrast enhancement at the trigone of the left lateral ventricle for which partial resection followed by radiotherapy was performed. However, mass regrowth was observed, with the patient eventually succumbing to her disease 11 months after her third surgery. Histopathological analyses of the first and second surgical specimens identified pseudostratified cuboidal epithelial cells, with no nuclear or cellular atypia resembling gastrointestinal mucosa, lining the inner surface of the cystic wall. Based on these findings the lesion was diagnosed as NC. The third surgical specimen exhibited apparent malignant features of the epithelial cells with elongated and hyperchromatic nuclei, several mitotic figures, small necrotic foci, and a patternless or sheet-like arrangement. Based on these findings, the lesion was diagnosed as NC with malignant transformation. Next-generation sequencing revealed KRAS p.G12D mutation in all specimens. Additionally, the third surgical specimen harbored the following 12 de novo gene alterations: ARID1A loss, BAP1 p.F170L, CDKN1B loss, CDKN2A loss, CDKN2B loss, FLCN loss, PTCH1 loss, PTEN loss, PTPRD loss, SUFU loss, TP53 loss, and TSC1 loss. The aforementioned results suggest that KRAS mutation is associated with the development of the NC, and that the additional gene alterations contribute to malignant transformation of the NC.

Novel Repositioning Therapy for Drug-Resistant Glioblastoma: In Vivo Validation Study of Clindamycin Treatment Targeting the mTOR Pathway and Combination Therapy with Temozolomide.

Multimodal therapy including surgery, radiation treatment, and temozolomide (TMZ) is performed on glioblastoma (GBM). However, the prognosis is still poor and there is an urgent need to develop effective treatments to improve survival. Molecular biological analysis was conducted to examine the signal activation patterns in GBM specimens and remains an open problem. Advanced macrolides, such as azithromycin, reduce the phosphorylation of p70 ribosomal protein S6 kinase (p70S6K), a downstream mammalian target of rapamycin (mTOR) effector, and suppress the proliferation of T-cells. We focused on its unique profile and screened for the antitumor activity of approved macrolide antibiotics. Clindamycin (CLD) reduced the viability of GBM cells in vitro. We assessed the effects of the candidate macrolide on the mTOR pathway through Western blotting. CLD attenuated p70S6K phosphorylation in a dose-dependent manner. These effects on GBM cells were enhanced by co-treatment with TMZ. Furthermore, CLD inhibited the expression of the O6-methylguanine-DNA methyltransferase (MGMT) protein in cultured cells. In the mouse xenograft model, CLD and TMZ co-administration significantly suppressed the tumor growth and markedly decreased the number of Ki-67 (clone MIB-1)-positive cells within the tumor. These results suggest that CLD suppressed GBM cell growth by inhibiting mTOR signaling. Moreover, CLD and TMZ showed promising synergistic antitumor activity.

Detection of 2-Hydroxyglutarate by 3.0-Tesla Magnetic Resonance Spectroscopy in Gliomas with Rare IDH Mutations: Making Sense of "False-Positive" Cases.

We have previously published a study on the reliable detection of 2-hydroxyglutarate (2HG) in lower-grade gliomas by magnetic resonance spectroscopy (MRS). In this short article, we re-evaluated five glioma cases originally assessed as isocitrate dehydrogenase (IDH) wildtype, which showed a high accumulation of 2HG, and were thought to be false-positives. A new primer was used for the detection of IDH2 mutation by Sanger sequencing. Adequate tissue for DNA analysis was available in 4 out of 5 cases. We found rare IDH2 mutations in two cases, with IDH2 R172W mutation in one case and IDH2 R172K mutation in another case. Both cases had very small mutant peaks, suggesting that the tumor volume was low in the tumor samples. Thus, the specificity of MRS for detecting IDH1/2 mutations was higher (81.3%) than that originally reported (72.2%). The detection of 2HG by MRS can aid in the diagnosis of rare, non-IDH1-R132H IDH1 and IDH2 mutations in gliomas.

[Surgical Case of Accidental Infantile Acute Subdural Hematoma Caused by Household Minor Head Trauma:Hyperperfusion during Postoperative Hemispheric Hypodensity, Namely "Big Black Brain"].

We experienced a case of an accidental infantile acute subdural hematoma caused by household minor head trauma(Nakamura type I intracranial hemorrhage)with postoperative hemispheric hypodensity lesion(Big Black Brain)whose pathophysiology was analyzed using perfusion MRI. A ten-month-old boy was admitted to our hospital in a comatose state. His mother revealed that the boy suffered a fall from a sofa bed. A CT scan indicated massive acute subdural hematoma in the left cerebral hemisphere. Emergency craniotomy and hematoma evacuation were performed. On postoperative day 3, CT revealed hemispheric hypodensity, and the boy suffered from status epilepticus. MRI on the following day showed widespread white matter hyperintensity in diffusion-weighted images, and MRA demonstrated dilation of the middle cerebral artery. Perfusion MRI using the dynamic susceptibility contrast method revealed a marked increase in cerebral blood flow in the left hemisphere. These abnormal MRI and MRA findings disappeared on postoperative day 13. Status epilepticus also improved upon administration of multi-antiepileptic drugs. Fundoscopy findings on postoperative day 3 showed small bilateral petechial or brush retinal hemorrhages. However, whole-body examination did not show any problems, and was consistent with the mother's account. Thus, we judged non-abusive head trauma. Although follow-up MRI showed diffuse atrophy of the left cerebral hemisphere, the boy aged well without obvious paresis or verbal developmental delay as judged by a follow-up more than a year later. Based on these results, we speculated that hyperperfusion caused by dilation of the cerebral artery was related to the postoperative hemispheric hypodensity, namely "Big Black Brain".

A Case of Curative Onyx Embolization for Tentorial dAVF via Low-flow Feeders with Temporary Balloon Occlusion of High-flow Feeders.

Objective: For curative Onyx embolization of dural arteriovenous fistulas (dAVF) with multiple feeders, it is essential to select the optimal target artery as well as to control the blood flow at the fistula point. We report a case of tentorial dAVF (TdAVF) treated by Onyx embolization under flow control using balloon catheters. Case Presentation: A 66-year-old male was admitted to our hospital for treatment of TdAVF detected incidentally by MRI, which revealed a dilated and tortuous vein around the cerebellum. Cerebral angiography demonstrated a TdAVF, fed mainly by bilateral middle meningeal arteries (MMA) and bilateral occipital arteries (OA), with the fistula point at the torcular and venous drainage to the two superior vermian veins (SVVs). Onyx 18 was injected from the low-flow feeder of the MMA under flow control by occluding the high-flow feeder of the OA using balloon catheters, obliterating the arteriovenous shunt. Conclusion: In treatment of TdAVF involving low- and high-flow feeders, Onyx embolization via the low-flow feeder with temporary balloon occlusion of other high-flow feeders is a useful method. This technique makes it easier for Onyx to penetrate the fistula point.

Reliable diagnosis of IDH-mutant glioblastoma by 2-hydroxyglutarate detection: a study by 3-T magnetic resonance spectroscopy.

We have previously reported that reliable detection of 2-hydroxyglutarate (2HG) in isocitrate dehydrogenase (IDH)-mutant WHO grade 2 and 3 gliomas is possible utilizing 3.0-T single-voxel magnetic resonance spectroscopy (SVMRS). We set out to determine whether the same method could be applied to detect 2HG in IDH-mutant glioblastoma. Forty-four patients harboring glioblastoma underwent pre-operative MRS evaluation to detect 2HG and other metabolites. Presence of IDH-mutations was determined by IDH1 R132H immunohistochemical analysis and DNA sequencing of surgically obtained tissues. Six out of 44 (13.6%) glioblastomas were IDH-mutant. IDH-mutant glioblastoma exhibited significantly higher accumulation of 2HG (median 3.191 vs. 0.000 mM, p < 0.0001, Mann-Whitney test). A cutoff of 2HG = 0.897 mM achieved high sensitivity (100.0%) and specificity (92.59%) in determining IDH-mutation in glioblastoma. Glioblastoma with high 2HG accumulation did not have significantly longer overall survival than glioblastoma with low 2HG accumulation (p = 0.107, log-rank test). Non-invasive and reliable detection of 2HG in IDH-mutant glioblastoma was possible by 3.0-T SVMRS.

Chemical Screening Identifies EUrd as a Novel Inhibitor Against Temozolomide-Resistant Glioblastoma-Initiating Cells.

Glioblastoma (GBM), one of the most malignant human cancers, frequently recurs despite multimodal treatment with surgery and chemo/radiotherapies. GBM-initiating cells (GICs) are the likely cell-of-origin in recurrences, as they proliferate indefinitely, form tumors in vivo, and are resistant to chemo/radiotherapies. It is therefore crucial to find chemicals that specifically kill GICs. We established temozolomide (the standard medicine for GBM)-resistant GICs (GICRs) and used the cells for chemical screening. Here, we identified 1-(3-C-ethynyl-ß-d-ribopentofuranosyl) uracil (EUrd) as a selective drug for targeting GICRs. EUrd induced the death in GICRs more effectively than their parental GICs, while it was less toxic to normal neural stem cells. We demonstrate that the cytotoxic effect of EUrd on GICRs partly depended on the increased expression of uridine-cytidine kinase-like 1 (UCKL1) and the decreased one of 5'-nucleotidase cytosolic III (NT5C3), which regulate uridine-monophosphate synthesis positively and negatively respectively. Together, these findings suggest that EUrd can be used as a new therapeutic drug for GBM with the expression of surrogate markers UCKL1 and NT5C3. Stem Cells 2016;34:2016-2025.

Immunohistochemical profiles of IDH1, MGMT and P53: practical significance for prognostication of patients with diffuse gliomas.

Genetic and epigenetic status, including mutations of isocitrate dehydrogenase (IDH) and TP53 and methylation of O(6) -methylguanine-DNA methyltransferase (MGMT), are associated with the development of various types of glioma and are useful for prognostication. Here, using routinely available histology sections from 312 patients with diffuse gliomas, we performed immunohistochemistry using antibodies specific for IDH1 mutation, MGMT methylation status, and aberrant p53 expression to evaluate the possible prognostic significance of these features. With regard to overall survival (OS), univariate analysis indicated that an IDH1-positive profile in patients with glioblastoma (GBM), anaplastic astrocytoma (AA), anaplastic oligoastrocytoma and oligodendroglioma, or a MGMT-negative profile in patients with GBM and AA were significantly associated with a favorable outcome. Multivariate analysis revealed that both profiles were independent factors influencing prognosis. The OS of patients with IDH1-positive/MGMT-negative profiles was significantly longer than that of patients with negative/negative and negative/positive profiles. A p53 profile was not an independent prognostic factor. However, for GBM/AA patients with IDH1-negative/MGMT-negative profiles, p53 overexpression was significantly associated with an unfavorable outcome. Thus, the immunohistochemical profiles of IDH1 and MGMT are of considerable significance in gliomas, and a combination of IDH1, MGMT and p53 profiles may be useful for prognostication of GBM/AA.

Cortico-cortical activity between the primary and supplementary motor cortex: An intraoperative near-infrared spectroscopy study.

BACKGROUND: The supplementary motor area (SMA) makes multiple reciprocal connections to many areas of the cerebral cortices, such as the primary motor cortex (PMC), anterior cingulate cortex, and various regions in the parietal somatosensory cortex. In patients with SMA seizures, epileptic discharges from the SMA rapidly propagate to the PMC. We sought to determine whether near-infrared spectroscopy (NIRS) is able to intraoperatively display hemodynamic changes in epileptic network activities between the SMA and the PMC. CASE DESCRIPTIONS: In a 60-year-old male with SMA seizures, we intraoperatively delivered a 500 Hz, 5-train stimulation to the medial cortical surface and measured the resulting hemodynamic changes in the PMC by calculating the oxyhemoglobin (HbO2) and deoxyhemoglobin (HbR) concentration changes during stimulation. No hemodynamic changes in the lateral cortex were observed during stimulation of the medial surface corresponding to the foot motor areas. In contrast, both HbO2 and HbR increased in the lateral cortex corresponding to the hand motor areas when the seizure onset zone was stimulated. In the premotor cortex and the lateral cortex corresponding to the trunk motor areas, hemodynamic changes showed a pattern of increased HbO2 with decreased HbR. CONCLUSIONS: This is the first reported study using intraoperative NIRS to characterize the epileptic network activities between the SMA and PMC. Our intraoperative NIRS procedure may thus be useful in monitoring the activities of cortico-cortical neural pathways such as the language system.

Accumulation of 2-hydroxyglutarate in gliomas correlates with survival: a study by 3.0-tesla magnetic resonance spectroscopy.

INTRODUCTION: Previous magnetic resonance spectroscopy (MRS) and mass spectroscopy studies have shown accumulation of 2-hydroxyglutarate (2HG) in mutant isocitrate dehydrogenase (IDH) gliomas. IDH mutation is known to be a powerful positive prognostic marker in malignant gliomas. Hence, 2HG accumulation in gliomas was assumed to be a positive prognostic factor in gliomas, but this has not yet been proven. Here, we analyzed 52 patients harboring World Health Organization (WHO) grade II and III gliomas utilizing 3.0-tesla MRS. RESULTS: Mutant IDH gliomas showed significantly higher accumulation of 2HG (median 5.077 vs. 0.000, p =0.0002, Mann-Whitney test). 2HG was detectable in all mutant IDH gliomas, whereas in 10 out of 27 (37.0%) wild-type IDH gliomas, 2HG was below the detectable range (2HG =0) (p =0.0003, chi-squared test). Screening for IDH mutation by 2HG analysis was highly sensitive (cutoff 2HG =1.489 mM, sensitivity 100.0%, specificity 72.2%). Gliomas with high 2HG accumulation had better overall survival than gliomas with low 2HG accumulation (p =0.0401, Kaplan-Meier analysis). DISCUSSION: 2HG accumulation detected by 3.0-tesla MRS not only correlates well with IDH status, but also positively correlates with survival in WHO grade II and III gliomas.

Neuronal differentiation associated with Gli3 expression predicts favorable outcome for patients with medulloblastoma.

Medulloblastoma (MB) is a malignant cerebellar tumor arising in children, and its ontogenesis is regulated by Sonic Hedgehog (Shh) signaling. No data are available regarding the correlation between expression of Gli3, a protein lying downstream of Shh, and neuronal differentiation of MB cells, or the prognostic significance of these features. We re-evaluated the histopathological features of surgical specimens of MB taken from 32 patients, and defined 15 of them as MB with neuronal differentiation (ND), three as MB with both glial and neuronal differentiation (GD), and 14 as differentiation-free (DF) MB. Gli3-immunoreactivity (IR) was evident as a clear circular stain outlining the nuclei of the tumor cells. The difference in the frequency of IR between the ND+GD (94.4%) and DF (0%) groups was significant (P < 0.001). The tumor cells with ND showed IR for both Gli3 and neuronal nuclei. Ultrastructurally, Gli3-IR was observed at the nuclear membrane. The overall survival and event-free survival rates of the patients in the ND group were significantly higher than those in the other groups. The expression profile of Gli3 is of considerable significance, and the association of ND with this feature may be prognostically favorable in patients with MB.

"Gliomatosis encephali" as a novel category of brain tumors by the first autopsy case report of gliomatosis cerebelli.

Gliomatosis cerebri is a rare diffuse glioma that is neither mass-forming nor necrotic, and does not disrupt existing structures. Gliomatosis occurring in the cerebellum is known as gliomatosis cerebelli, and only three such cases examined by biopsy have been reported. Here we describe the first autopsy findings of a patient who was diagnosed as having gliomatosis in the cerebellum. Neuropathological examination identified the tumor cells as being positive for glial fibrillary acidic protein, vimentin and nestin, with atypical nuclei that were cashew-nut- or dishcloth-gourd-shaped. These tumor cells were dense in the right cerebellum, but also spread broadly throughout the brain including the left cerebrum and optic nerve. Mitotic figures were frequently seen in the cerebellum, brain stem and cerebrum. Scherer's secondary structures were evident not only in the cerebellum but also the cerebrum. No necrosis, microvascular proliferation or destruction of anatomical structures was detected in the whole brain. Differences in the origin of the tumors of the gliomatoses cerbri and cerebelli suggests these tumors are different types of brain tumors. Thus the findings support that the gliomatosis cerebelli is a novel type of brain tumor classification. Furthermore, by the similarities of the histological features among the tumors, it appears appropriate to establish a novel category of "gliomatosis encephali" which includes both gliomatosis cerebri and gliomatosis cerebelli.

Advantages of dose-dense methotrexate protocol for primary central nervous system lymphoma: comparison of two different protocols at a single institution.

The efficacy and toxicity of high-dose methotrexate (HD-MTX)-based chemotherapy were retrospectively reviewed in patients with primary central nervous system lymphoma (PCNSL). All immunocompetent patients with histologically or radiographically diagnosed PCNSL treated between 2006 and 2012 at Niigata University Hospital were enrolled. Thirty-eight patients with a diagnosis of PCNSL were treated with one of two regimens during different time periods. During the first period, from 2006 to 2009, three 3-week cycles of MPV (MTX + procarbazine + vincristine) were administered (MPV3 group). In the second period, from 2010 to 2012, five 2-week cycles of MTX were administered (MTX5 group). High-dose cytarabine was used in both groups following HD-MTX-based chemotherapy. Whole-brain radiotherapy was used for patients who did not attain a complete response (CR) based on magnetic resonance images. In the MPV3 group, 20 out of 23 patients (87%) completed the planned treatment. The CR rate after chemotherapy was 30%, and 57% after radiation therapy. Thirteen out of 15 patients (87%) in the MTX5 group completed the planned treatment. The CR rates after chemotherapy and radiation therapy were 53% and 93%, respectively. Renal dysfunction was assessed by measuring creatinine clearance rates, which were very similar in both groups. In terms of hematologic toxicity and other adverse reactions, there was no significant difference between the two groups. In conclusion, dose-dense MTX chemotherapy improved outcome with acceptable toxicity compared with the treatment schedule for three cycles of MPV treatment.

[Intraoperative monitoring of motor evoked potentials during glioma removal].

OBJECTIVE: To determine whether motor evoked potentials(MEPs)provide reliable monitoring of the motor system during resection of gliomas in or adjacent to the motor cortex or pyramidal tract. MATERIALS AND METHODS: MEP recording was performed during 64 operations in 55 patients harboring gliomas. Intraoperative MEP findings were classified into 3 groups:Group A was defined as having no significant MEP changes, Group B as having reversible MEP changes(?50% amplitude decrease or loss), and Group C as having irreversible changes. Postoperative motor function was evaluated according to the presence/absence of deterioration immediately after surgery and 1 month later, as compared to preoperative motor status RESULTS: Immediately after surgery, 13 of 39(33%)patients in Group A, 6 of 17(35%)in Group B, and 7 of 8(88%)in Group C experienced deterioration of motor function. One month after surgery, 4 of 39(10%)patients in Group A, 3 of 17(18%)in Group B, and 4 of 8(50%)showed deterioration of motor function. Both immediately(χ2=8.3, p<0.05)and 1 month(χ2=6.9, p<0.05)after surgery, MEP alterations correlated significantly with postoperative deterioration of motor function. Despite MEPs being stable throughout surgery(Group A), there were some patients with deterioration of motor function initially appearing to represent false negative monitoring. However, these deteriorations were confirmed to have been caused by secondary hemorrhage, venous return dysfunction, postoperative convulsion, or resection of the supplementary motor area. CONCLUSIONS: MEP monitoring provides reliable information on the motor system during glioma surgery. Although false negative MEP results may exist in some patients, most data were not influenced by intraoperative manipulation but rather were attributable to secondary postoperative events.