A Ruptured Spetzler and Martin Grade V Arteriovenous Malformation in a Child Treated With Radiotherapy Followed by Embolization: A Case Report and Literature Review.

Treatment of ruptured high-grade Spetzler-Martin (S&M) arteriovenous malformation (AVM) is challenging and requires a multidisciplinary treatment approach. Here, we report a case of ruptured giant callosal Grade V AVM in a child initially treated with stereotactic radiotherapy followed by endovascular embolization with Onyx; a management approach recently described in a few reports on the "postradiosurgical embolization" method. Complete obliteration was achieved 20 months after stereotactic radiotherapy and embolization. In this article, we discuss the usefulness and significance of postradiosurgical embolization, particularly for high-grade AVMs. To our knowledge, this is the first case with a giant Spetzler-Martin Grade V AVM treated with a postradiosurgical embolization method.

Intraoperative transcranial facial motor evoked potential monitoring in surgery of cerebellopontine angle tumors predicts early and late postoperative facial nerve function.

OBJECTIVE: We propose a novel method that predicts facial nerve function (FNF) calculated from the drop and recovery of facial motor evoked potential (FMEP) amplitude ratio during the surgery of cerebellopontine angle tumors. METHODS: We enrolled 73 patients with cerebellopontine angle tumor, and used a biphasic, constant current, and suprathreshold stimulation (BCS) protocol to record FMEP of the orbicularis oris. We measured the intraoperative minimum-to-baseline amplitude ratio (MBR), the final-to-baseline amplitude ratio (FBR), and the recovery value (RV). RV was measured by subtracting MBR from FBR. Using those values, we evaluated FNF both at early postoperative (EP) and late postoperative (LP) periods. RESULTS: We successfully obtained 62 FMEP readings. Facial palsies occurred in 22 patients during the EP period, and 14 patients recovered during the LP period. Both MBR and FBR showed a significant correlation with FNF in the EP period. RV showed a good predictive power of FNF recovery during the LP period for the first time. CONCLUSIONS: RV is a new and useful predictor of FNF recovery. MBR can be an intraoperative predictor of FNF in the EP period. SIGNIFICANCE: FNF outcome in the early and late postoperative periods can be predicted by FMEP.

A novel needle electrode for intraoperative fourth cranial nerve neurophysiological mapping.

OBJECTIVES: Trochlear nerve (CN-IV) mapping method has not been confirmed to date. The compound muscle action potential (CMAP) of CN-IV cannot be recorded because of the low mapping sensitivity and anatomical characteristics of the superior oblique muscle (SOM). The aim of this study was to evaluate the effectiveness of a novel needle electrode (NNE), for the intraoperative mapping of CN-IV. MATERIALS AND METHODS: The NNEs were inserted in the target extraocular muscles in 19 patients. We compared the CMAP amplitude of the NNE with that of the conventional needle electrode (CNE). Furthermore, we investigated the dissimilarity between the CMAP of the CN-IV and other extraocular cranial nerves (ECNs) and the correlation between the readings of the CN-IV mapping and its postoperative functional outcome. RESULTS: The CMAP of CN-IV has been measured in nine patients (47.4%). The CMAP of CN-IV was distinguishable from other ECNs. The CMAP of the NNE was found to be three times higher than that of the CNE. Although the NNE has shown the potential to record the CN-IV's CMAP, 4 cases ended up having a CN-IV postoperative dysfunction. CONCLUSIONS: For the first time, we confirmed the possibility of intraoperative mapping the CN-IV using an NNE inserted into the SOM. The NNE can also be useful for other neurophysiological monitoring methods.

Secondary brain tumors after cranial radiation therapy: A single-institution study.

AIM: To study the probability of developing secondary brain tumors after cranial radiotherapy.Background Patients treated with cranial radiotherapy are at risk for developing secondary brain tumors. PATIENTS AND METHODS: We planned an institutional survey for secondary brain tumors in survivors after cranial irradiation and reviewed the 30-year duration data. Event analysis and cumulative proportion curves were performed to generally estimate the cumulative proportion of developing secondary brain tumors, cavernoma and meningioma at different periods of time. RESULTS: Secondary brain tumors occurred in 21% of cases: 10% were cavernomas, 6% were meningiomas, 3% were skull osteomas, and 1% were anaplastic astrocytoma. The cumulative proportion of developing secondary brain tumor was 6% at 10 years and 20% at 20 years, while the cumulative proportion for developing cavernomas and meningiomas was 16% and 7% at 20 years, respectively. CONCLUSION: Our study shows that patients who received cranial irradiation were at risk of secondary brain tumors such as cavernomas and meningiomas. Thus, a meticulous follow-up of cancer survivors with history of cranial irradiation by an annual MRI scan is justifiable. This will help clinicians to detect secondary brain tumors early and make its management much easier.

Bevacizumab Therapy of Neurofibromatosis Type 2 Associated Vestibular Schwannoma in Japanese Patients.

We conducted a feasibility study to investigate the therapeutic effect of bevacizumab on vestibular schwannomas (VS) associated with neurofibromatosis type 2 (NF2) in a sample of Japanese patients. Ten NF2 patients were selected between 2013 and 2018: nine women and one man, with ages ranging from 12 to 45 years (mean: 29.4). Bevacizumab was administered intravenously in 5 mg/kg doses four times, with an inter-dose interval of 2 weeks. Seventeen tumors were followed for 3-72 months (mean: 39). A reduction from baseline tumor volume of at least 20% was considered a therapeutic radiologic response. Maximum reduction in tumor volume was identified in the 3rd month in 11 tumors, and in the 6th month in three tumors. Three tumors did not show any response to bevacizumab. A radiologic response was detected in seven tumors (41%). There was a significantly lower tumor volume mean in the 3rd month in comparison to the baseline for the entire sample. Tumors in patients aged 25 and above showed a significant reduction in volume in the 3rd month and significantly lower tumor-volume-to-baseline ratio than younger patients in both the 3rd and 6th months. The interaction between 'time' and 'age group' factors significantly affected the therapeutic outcome of bevacizumab on tumor volume. This study investigated the therapeutic effects of bevacizumab on NF2-associated vestibular schwannomas in Japanese patients. Bevacizumab appears to be a useful therapeutic choice in NF2 cases to control the growth of VS. Therefore, a randomised control trial to prove this assumption is necessary.

Population Characteristics and Progressive Disability in Neurofibromatosis Type 2.

OBJECTIVE: To characterize the clinical features of patients with neurofibromatosis type 2 (NF2) and determine prognostic risk factors for progressive disabilities. METHODS: In this retrospective cohort study of the Japanese national NF2 registry between 2009 and 2013, clinical data (demographic, history, oncologic, and neurologic) of 807 patients with a diagnosis of NF2 were analyzed. The overall severity of neurologic disability was assessed using a comprehensive 25-point scoring system encompassing a wide variety of neurologic deficits. In 587 patients in whom longitudinal disability data were available, multivariate logistic regression was performed to identify risk factors for significant progression of disability. RESULTS: The clinical characteristics of the Japanese NF2 population were heterogeneous. The median age of onset was 24 years (range, 1-80 years), the male:female ratio was 1:1.29, and the initial severity score was 4 (range, 0-22) out of 25 points. A family history of NF2 was present in 33% of the patients. Most frequent clinical features were bilateral cranial nerve VIII nerve sheath tumor (NST) in 87%, spinal NST in 80%, hearing loss in 65%, spinal dysfunction in 50%, intracranial meningioma in 49%, and facial paresis in 36%. The disability score progressed by ≥5 points in 6.1% of patients over the study period. Based on multivariate logistic regression analyses, the significant independent risk factors of progression (P value) included age of onset <25 years (P = 0.015), positive family history (P = 0.007), positive treatment history (P = 0.026), hearing loss (P = 0.014), facial paresis (P = 0.015), blindness (P = 0.011), and hemiparesis (P = 0.025). CONCLUSIONS: The Japanese NF2 population has heterogeneous clinical features. Risk factors for progressive disability include younger age of onset, positive family history, positive treatment history, and specific neurologic deficits.

Polar spongioblastoma: A high-grade glioma that does not contain the IDH1 mutation or 1p/19q LOH.

We report a case of an unusual glioma termed "primitive polar spongioblastoma" that displayed characteristic palisading tumor cells at the light microscopic level. The patient was a 52-year-old woman who underwent subtotal removal for a left frontotemporal tumor. The palisading pattern was present throughout the tumor. Several glial markers were revealed by immunohistochemical examination, but no neuronal markers were observed. Genetic studies showed O-6-methylguanine-DNA methyltransferase (MGMT) methylation, wild type IDH1, and the absence of 1p/19q loss of heterozygosity (LOH) in the tumor genes. Based on histological and genetic features, this tumor might not be suited to any of neuroepithelial tumor in the recent WHO classification. We consider that cases such as this should be temporarily set under a separate heading and be entrusted to future investigation after more cases have been accumulated.

[Posttraumatic pseudomeningocele--a case report].

Pseudomeningocele is a rare complication of head trauma. An 7-year-old male child who fell from playground equipment was admitted to hospital with lambdoid sutural diastatic fracture. As epidural and subgaleal fluid collections gradually developed from the subsequent day of admission, a subgaleal drain was placed for cerebrospinal fluid (CSF) diversion. In addition, the scalp just over the fractured segment was compressed by band after drainage whereby the CSF leak was stopped. On the basis of our experience with this case, we suggest that appropriate management enables repair of posttraumatic pseudomeningocele in early stages of injury.