Navigated transcranial magnetic stimulation for glioma removal: prognostic value in motor function recovery from postsurgical neurological deficits

OBJECTIVE The aim of the present study was to evaluate the usefulness of navigated transcranial magnetic stimulation (nTMS) as a prognostic predictor for upper-extremity motor functional recovery from postsurgical neurological deficits. METHODS Preoperative and postoperative nTMS studies were prospectively applied in 14 patients (mean age 39 ± 12 years) who had intraparenchymal brain neoplasms located within or adjacent to the motor eloquent area in the cerebral hemisphere. Mapping by nTMS was done 3 times, i.e., before surgery, and 1 week and 3 weeks after surgery. To assess the response induced by nTMS, motor evoked potential (nTMS-MEP) was recorded using a surface electromyography electrode attached to the abductor pollicis brevis (APB). The cortical locations that elicited the largest electromyography response by nTMS were defined as hotspots. Hotspots for APB were confirmed as positive responsive sites by direct electrical stimulation (DES) during awake craniotomy. The distances between hotspots and lesions (D_HS-L) were measured. Postoperative neurological deficits were assessed by manual muscle test and dynamometer. To validate the prognostic value of nTMS in recovery from upper-extremity paresis, the following were investigated: 1) the correlation between D_HS-L and the serial grip strength change, and 2) the correlation between positive nTMS-MEP at 1 week after surgery and the serial grip strength change. RESULTS From the presurgical nTMS study, MEPs from targeted muscles were identified in 13 cases from affected hemispheres. In one case, MEP was not evoked due to a huge tumor. Among 9 cases from which intraoperative DES mapping for hand motor area was available, hotspots for APB identified by nTMS were concordant with DES-positive sites. Compared with the adjacent group (D_HS-L < 10 mm, n = 6), the nonadjacent group (D_HS-L ≥ 10 mm, n = 7) showed significantly better recovery of grip strength at 3 months after surgery (p < 0.01). There were correlations between D_HS-L and recovery of grip strength at 1 week, 3 weeks, and 3 months after surgery (r = 0.74, 0.68, and 0.65, respectively). Postsurgical nTMS was accomplished in 13 patients. In 9 of 13 cases, nTMS-MEP from APB muscle was positive at 1 week after surgery. Excluding the case in which nTMS-MEP was negative from the presurgical nTMS study, recoveries in grip strength were compared between 2 groups, in which nTMS-MEP at 1 week after surgery was positive (n = 9) or negative (n = 3). Significant differences were observed between the 2 groups at 1 week, 3 weeks, and 3 months after surgery (p < 0.01). Positive nTMS-MEP at 1 week after surgery correlated well with the motor recovery at 1 week, 3 weeks, and 3 months after surgery (r = 0.87, 0.88, and 0.77, respectively). CONCLUSIONS Navigated TMS is a useful tool for identifying motor eloquent areas. The results of the present study have demonstrated the predictive value of nTMS in upper-extremity motor function recovery from postsurgical neurological deficits. The longer D_HS-L and positive nTMS-MEP at 1 week after surgery have prognostic values of better recovery from postsurgical neurological deficits.

Roles of the Wada Test and Functional Magnetic Resonance Imaging in Identifying the Language-dominant Hemisphere among Patients with Gliomas Located near Speech Areas

This study examined the accuracy of functional magnetic resonance imaging (fMRI) in identifying the language-dominant hemisphere and the situations in which the Wada test can be skipped among patients with gliomas located near speech areas. We examined 74 patients [48 men (64.9%); mean ± standard deviation age of 42.7 ± 13.6 years (range: 13 to 70 years); 71 right-handed, 2 left-handed, and 1 ambidextrous] with gliomas located near speech areas. All patients underwent the Wada test and fMRI, and 34 patients underwent awake surgery. The “last-and-first” task was administered during fMRI. The Wada test was successful in determining the language-dominant hemisphere in 73 patients (98.6%): left hemisphere in 68 patients (91.9%), right hemisphere in 4 patients (5.4%), and bilateral in 1 patient (1.4%). The dominant hemisphere for right-handed patients (n = 71) was the left hemisphere in 67 patients (94.3%), right hemisphere in 3 patients (4.2%), and undetectable in 1 patient (1.4%). The fMRI was successful in determining the language-dominant hemisphere in 53 patients (71.6%). The results of the Wada test and fMRI were inconsistent in 5 patients (8.6%), of which 3 (5.2%) exhibited dominance in opposite hemispheres. Furthermore, 2 of these 3 cases (2.7%) were contralateral false positive cases, whereby fMRI identified the right-hemisphere as language dominant for right-handed individuals with tumors in the left hemisphere. Based on these findings, we concluded that the Wada test can be skipped if language dominancy can be detected by fMRI.

[A Case Report of Spontaneous Cerebrospinal Fluid Otorrhea]

Spontaneous cerebrospinal fluid(CSF)otorrhea is less common than CSF leakage caused by trauma, and rarely occurs in adults. We report an adult case of CSF otorrhea. A 71-year-old woman with no traumatic or otologic history was hospitalized due to bacterial meningitis. After hospitalization, CSF leakage started suddenly from the left external ear canal. A high resolution CT scan with intrathecal administration of contrast material revealed CSF leakage in the left ear canal and multiple bone erosions in both the tegmen mastoideum and the posterior fossa aspect of the petrous bone. We performed closure and surgery via the middle fossa approach. We identified a bone defect in the tegmen mastoideum but could not detect any obvious abnormality in the dura mater. We placed both a pericranial flap and a free abdominal fat on the middle base of the skull as sealing materials. There was no recurrence of CSF otorrhea following surgery. In this surgery, the use of a multilayered closure technique is very important to avoid the recurrence of CSF leakage.

KRIT1 mutations in three Japanese pedigrees with hereditary cavernous malformation

Cerebral cavernous malformation is a neurovascular abnormality that can cause seizures, focal neurological deficits and intracerebral hemorrhage. Familial forms of this condition are characterized by de novo formation of multiple lesions and are autosomal-dominantly inherited via CCM1/KRIT1, CCM2/MGC4607 and CCM3/PDCD10 mutations. We identified three truncating mutations in KRIT1 from three Japanese families with CCMs: a novel frameshift mutation, a known frameshift mutation and a known splice-site mutation that had not been previously analyzed for aberrant splicing.

Extremely rare persistent primitive artery passing through the jugular foramen with symptomatic ipsilateral carotid artery stenosis

Primitive arteries are persistent fetal anastomoses between the carotid and vertebral-basilar circulation. Although rare, persistent primitive arteries can remain at birth. A 73-year-old woman presented with cerebral infarction to the posterior circulation caused by symptomatic common carotid artery stenosis with an unnamed and extremely rare persistent primitive artery. This anomalous vessel branched from the extracranial internal carotid artery and passed through the ipsilateral jugular foramen into the posterior cranial fossa and merged into the basilar artery. To our knowledge, this is the first case of a persistent primitive artery passing through the jugular foramen with symptomatic common carotid artery stenosis.

Permeability Surface Area Product Using Perfusion Computed Tomography Is a Valuable Prognostic Factor in Glioblastomas Treated with Radiotherapy Plus Concomitant and Adjuvant Temozolomide

OBJECTIVE

The current standard treatment protocol for patients with newly diagnosed glioblastoma (GBM) includes surgery, radiotherapy, and concomitant and adjuvant temozolomide (TMZ). We hypothesized that the permeability surface area product (PS) from a perfusion computed tomography (PCT) study is associated with sensitivity to TMZ. The aim of this study was to determine whether PS values were correlated with prognosis of GBM patients who received the standard treatment protocol.

METHODS

This study included 36 patients with GBM that were newly diagnosed between October 2005 and September 2014 and who underwent preoperative PCT study and the standard treatment protocol. We measured the maximum value of relative cerebral blood volume (rCBVmax) and the maximum PS value (PSmax). We statistically examined the relationship between PSmax and prognosis using survival analysis, including other clinicopathologic factors (age, Karnofsky performance status [KPS], extent of resection, O6-methylguanine-DNA methyltransferase [MGMT] status, second-line use of bevacizumab, and rCBVmax).

RESULTS

Log-rank tests revealed that age, KPS, MGMT status, and PSmax were significantly correlated with overall survival. Multivariate analysis using the Cox regression model showed that PSmax was the most significant prognostic factor. Receiver operating characteristic curve analysis showed that PSmax had the highest accuracy in differentiating longtime survivors (LTSs) (surviving more than 2 years) from non-LTSs. At a cutoff point of 8.26 mL/100 g/min, sensitivity and specificity were 90% and 70%, respectively.

CONCLUSIONS

PSmax from PCT study can help predict survival time in patients with GBM receiving the standard treatment protocol. Survival may be related to sensitivity to TMZ.

Nonconvulsive Status Epilepticus in the Neurosurgical Setting

Herein, we review the current state of nonconvulsive status epilepticus (NCSE). NCSE has recently been recognized as one of the causes of unexplained impaired consciousness in the neurosurgical or neurocritical setting. The causes of NCSE include not only central nervous system disorders such as craniotomy, stroke, traumatic brain injury, and central nervous system inflammation, but also severe critical conditions such as sepsis and uremia, among others. NCSE shows no overt clinical manifestations; therefore, prompt and correct diagnosis is difficult. The diagnosis of NCSE should be made by electroencephalogram (EEG), especially continuous EEG (CEEG) monitoring, because NCSE is caught only by prolonged recording. However, the interpretation of the EEG findings is also challenging because of the varying EEG characteristic of NCSE. While the diagnosis should be based on temporal or spatial EEG changes, several definitions and criteria have been proposed, and uniform, universal criteria are still lacking. Once NCSE is diagnosed, antiepileptic drugs (AEDs) should be aggressively administrated. Although there are no standardized international therapeutic guidelines, several AEDs have been attempted in clinical practice in other countries, including fosphenytoin, midazolam, levetiracetam, and valproate. Particularly, several AEDs should be considered prior to using anesthetics. Finally, the prognosis of NCSE depends on the cause thereof; however, in general, earlier intervention for NCSE appears important in terms of better recovery.

Stent-assisted coil embolisation for bilateral vertebral artery dissecting aneurysms presenting with subarachnoid haemorrhage

Bilateral dissecting aneurysms presenting with subarachnoid haemorrhage are rare. The treatment strategy for bilateral vertebral artery dissecting aneurysms is controversial because the contralateral vertebral artery is already dissected and can easily undergo enlargement or bleed after non-reconstructive treatment procedures such as trapping or proximal occlusion. Here, we report a case of bilateral vertebral artery dissecting aneurysm presenting with subarachnoid haemorrhage that was treated with stent-assisted coiling for the ruptured side. A 42-year-old man was admitted to our hospital with sudden headache (WFNS grade 1). Computed tomography showed a high-density region in the basal cistern and posterior fossa with more haemorrhage on the right side (Fisher group 3). Three-dimensional computed tomography and three-dimensional rotational angiography demonstrated a bilateral round protrusion on the vertebral arteries with a diameter of 5 mm just distal to the posterior inferior cerebellar artery. Stent-assisted coiling was performed for the ruptured right side and conservative therapy was selected for the contralateral side. The ruptured side was well embolised, and the contralateral side was stable over the 12-month follow-up period after treatment. The treatment strategy for bilateral vertebral artery dissecting aneurysms presenting with subarachnoid haemorrhage is different from that for unilateral vertebral artery dissecting aneurysms. Non-reconstructive treatment procedures such as trapping may cause contralateral enlargement or rupture; therefore, reconstructive treatment may be appropriate for the ruptured side.

Stereotactic Thalamotomy for Hairdresser's Dystonia: A Case Series

BACKGROUND

Hairdresser's dystonia is a rarely reported form of focal hand dystonia, and the clinical course and treatment remains poorly understood.

OBJECTIVES

The aim of this report was to clarify the impact of thalamotomy on hairdresser's dystonia.

METHODS

Four consecutive patients with hairdresser's task-specific dystonia evaluated at Tokyo Women's Medical University Hospital between 2008 and 2013 were treated with stereotactic thalamotomy, and were recruited for this case series.

RESULTS

The mean age at the onset of symptoms was 37.25 ± 10.64 years, the median duration of symptoms was 4.25 ± 1.3 years, and the mean follow-up period was 17 ± 12.37 months. Two of the 4 patients returned to work with significant improvement following the stereotactic thalamotomy and the beneficial effects persisted for the duration of their clinical follow-up. The other 2 patients experienced transient improvements for up to 3 months. Surgical complications included only dysarthria in 2 patients, and did not interfere with their daily activities. No patients experienced a deterioration of dystonic symptoms after thalamotomy.

CONCLUSION

Although the benefits of thalamotomy remain vulnerable to incorrect or insufficient coagulation, stereotactic thalamotomy may be a feasible and effective procedure for patients with hairdresser's dystonia.

Reversible Cerebral Metabolism Changes Using Proton Magnetic Resonance Spectroscopy in a Patient with Intracranial Dural Arteriovenous Fistula: A Case Report

BACKGROUND

Cerebral metabolism can be disrupted by venous congestion in patients with intracranial dural arteriovenous fistula (DAVF), which may lead to adverse neurological outcomes. However, there are no clear indicators to guide cerebral evaluation and treatment selection in cases of DAVF. We describe a patient with a DAVF whose proton magnetic resonance spectroscopy ((1)H-MRS) findings were associated with improvements in clinical status.

CASE DESCRIPTION

An elderly woman with a history of myocardial infarction presented with progressive dementia, aphasia, and a severe headache. We detected a transverse-sigmoid sinus DAVF, as well as abnormal levels of lactate and N-acetylaspartic acid (NAA) in the (1)H-MRS, and successfully treated the patient using surgical sinus skeletonization. However, follow-up (1)H-MRS revealed inconsistent reversals in the levels of lactate and NAA. In addition, we calculated the NAA/creatinine ratios from before and after surgery, which revealed postoperative increases in the ratios for the left temporal, right parietal, and left parietal regions. These increases occurred concurrently with improvements in the patient's cognitive function.

CONCLUSIONS

(1)H-MRS may be useful for pretreatment detection of increased lactate levels, decreased NAA levels, and/or decreased NAA/creatinine ratios. These findings may indicate poorer cerebral metabolism, and show a need for more aggressive treatment. Furthermore, (1)H-MRS may be useful for evaluating the effect of conservative treatment and for indicating conversion to a more aggressive treatment.

Symptomatic epidural haematoma after cervical laminoplasty: a report of three cases

Symptomatic epidural haematoma after cervical laminoplasty is rare. We report 3 patients who required emergency evacuation of an epidural haematoma. Timely diagnosis and removal of the haematoma is important to prevent neurological deficits. The causative factors in these patients were preoperative coagulopathy, hypertension, and the malfunction of a closed-suction drain.

The role of 4D CT angiography for preoperative screening in patients with intracranial tumors

INTRODUCTION

Four-dimensional computed tomography angiography (4D CTA) is now becoming an often used diagnostic imaging modality for the assessment of patients with intracranial tumors. The purpose of this study was to demonstrate the utility of 4D CTA for preoperative screening in patients with intracranial tumors as well as to examine the correlation between perfusion data and grading of gliomas.

METHODS

We performed preoperative screening using 320-row detector CT scanner in 186 patients with intracranial tumors, and 115 patients were finally included in the study. Time-resolved subtracted maximum intensity projection images and volume-rendered images were reconstructed to evaluate vascular structures, tumor staining and incidental lesions. We also evaluated the perfusion functional map for gliomas to find correlations between their vascularity and tumor grading.

RESULTS

We evaluated gliomas in 70 patients, meningiomas in 29, and other tumors in 16. Patients with gliomas of a pathologically higher grade showed high cerebral blood volume (p < 0.05). Tumor staining was observed on MIP images for 12 meningiomas, 4 gliomas, and 3 other tumors. Fifty patients showed a mass effect on vascular structures, seven had cerebral venous sinus obstruction, and two had aneurysms. No iatrogenic accidents with the CT procedure were reported.

CONCLUSIONS

The 4D CTA technique is effective and safe for depicting vascular structures such as arteries, veins, tumor-related vessels, and direct and indirect anatomical complications such as vascular obstruction or vascular compression. This information is useful for preoperative screening. Although 4D CTA also provides perfusion data correlating with the tumor vascularity and grading of gliomas, its clinical value remains limited.

Hearing Preservation after Low-dose Gamma Knife Radiosurgery of Vestibular Schwannomas

The objective of the retrospective study was to evaluate the factors associated with hearing preservation after low-dose Gamma Knife radiosurgery (GKS) of vestibular schwannomas performed according to the modern standards. From January 2005 to September 2010, 141 consecutive patients underwent such treatment in Tokyo Women’s Medical University. Mean marginal dose was 11.9 Gy (range, 11–12 Gy). The doses for the brain stem, cranial nerves (V, VII, and VIII), and cochlea were kept below 14 Gy, 12 Gy, and 4 Gy, respectively. Out of the total cohort, 102 cases with at least 24 months follow-up were analyzed. Within the median follow-up of 56 months (range, 24–99 months) the crude tumor growth control was 92% (94 cases), whereas its actuarial rate at 5 years was 93%. Out of 49 patients with serviceable hearing on the side of the tumor before GKS, 28 (57%) demonstrated its preservation at the time of the last follow-up. No one evaluated factor, namely Gardner-Robertson hearing class before irradiation, Koos tumor stage, extension of the intrameatal part of the neoplasm up to fundus, nerve of tumor origin, presence of cystic changes in the neoplasm, and cochlea dose demonstrated statistically significant association with preservation of the serviceable hearing after radiosurgery. In conclusion, GKS of vestibular schwannomas performed according to the modern standards of treatment permits to preserve serviceable hearing on the side of the tumor in more than half of the patients. The actual causes of hearing deterioration after radiosurgery remain unclear.

Calcification on CT is a simple and valuable preoperative indicator of 1p/19q loss of heterozygosity in supratentorial brain tumors that are suspected grade II and III gliomas

Gliomas with 1p/19q loss of heterozygosity (LOH) are known to be associated with longer patient survival and higher sensitivity to treatment than tumors without 1p/19q LOH. This study was designed to clarify whether the preoperative finding of calcification on CT was correlated with 1p/19q LOH in patients with suspected WHO grade II and III gliomas. This study included 250 adult patients who underwent resection for primary supratentorial tumors at Tokyo Women's Medical University Hospital. The tumors were suspected, based on MRI findings, to be WHO grade II or III gliomas. The presence of calcification on the patients' CT images was qualitatively evaluated before treatment. After surgery, the resected tumors were examined to determine their 1p/19q status and mutations of IDH1 and p53. The presence of calcification was significantly correlated with 1p/19q LOH (P < 0.0001), with a positive predictive value of 91 %. The tumors of all the 78 patients with calcification were diagnosed as oligodendroglial tumors. Seventy of these patients showed classic oligodendroglial features, while 8 patients showed non-classic features. Calcification on CT is a simple and valuable preoperative indicator of 1p/19q LOH in supratentorial brain tumors that are suspected to be WHO grade II and III gliomas.

Internal carotid artery stenosis with persistent primitive hypoglossal artery treated with carotid artery stenting: A case report and literature review

Persistent primitive hypoglossal artery (PPHA) is a persistent carotid-basilar anastomosis. It rarely remains at birth. It occasionally may be a risk for ischemia and embolic infarction to the posterior cerebral circulation, especially in patients with carotid stenosis proximal to the origin of persistent primitive arteries. We describe a case of a 60-year-old woman with asymptomatic internal carotid artery (ICA) stenosis and ipsilateral PPHA successfully treated by carotid artery stenting (CAS). A few cases of CAS for ICA stenosis with PPHA have been reported, but the strategy and methods in each case were different because of its unique anatomy and hemodynamics. It is essential to prevent distal embolisms and preserve blood flow at the territory of both the ICA and PPHA. The protection method should be selected carefully. We review the literature and discuss appropriate treatment strategies.

Difficulty in identification of the frontal language area in patients with dominant frontal gliomas that involve the pars triangularis

OBJECTIVE Identification of language areas using functional brain mapping is sometimes impossible using current methods but essential to preserve language function in patients with gliomas located within or near the frontal language area (FLA). However, the factors that influence the failure to detect language areas have not been elucidated. The present study evaluated the difficulty in identifying the FLA in dominant-side frontal gliomas that involve the pars triangularis (PT) to determine the factors that influenced failed positive language mapping. METHODS Awake craniotomy was performed on 301 patients from April 2000 to October 2013 at Tokyo Women's Medical University. Recurrent cases were excluded, and patients were also excluded if motor mapping indicated their glioma was in or around the motor area on the dominant or nondominant side. Eighty-two consecutive cases of primary frontal glioma on the dominant side were analyzed for the present study. MRI was used for all patients to evaluate whether tumors involved the PT and to perform language functional mapping with a bipolar electrical stimulator. Eighteen of 82 patients (mean age 39 ± 13 years) had tumors that showed involvement of the PT, and the detailed characteristics of these 18 patients were examined. RESULTS The FLA could not be identified with intraoperative brain mapping in 14 (17%) of 82 patients; 11 (79%) of these 14 patients had a tumor involving the PT. The negative response rate in language mapping was only 5% in patients without involvement of the PT, whereas this rate was 61% in patients with involvement of the PT. Univariate analyses showed no significant correlation between identification of the FLA and sex, age, histology, or WHO grade. However, failure to identify the FLA was significantly correlated with involvement of the PT (p < 0.0001). Similarly, multivariate analyses with the logistic regression model showed that only involvement of the PT was significantly correlated with failure to identify the FLA (p < 0.0001). In 18 patients whose tumors involved the PT, only 1 patient had mild preoperative dysphasia. One week after surgery, language function worsened in 4 (22%) of 18 patients. Six months after surgery, 1 (5.6%) of 18 patients had a persistent mild speech deficit. The mean extent of resection was 90% ± 7.1%. Conclusions Identification of the FLA can be difficult in patients with frontal gliomas on the dominant side that involve the PT, but the positive mapping rate of the FLA was 95% in patients without involvement of the PT. These findings are useful for establishing a positive mapping strategy for patients undergoing awake craniotomy for the treatment of frontal gliomas on the dominant side. Thoroughly positive language mapping with subcortical electrical stimulation should be performed in patients without involvement of the PT. More careful continuous neurological monitoring combined with subcortical electrical stimulation is needed when removing dominant-side frontal gliomas that involve the PT.