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.

[Electroencephalographic features of nonconvulsive status epilepticus]

Continuous EEG monitoring (cEEG) has been recently applied in a neurocritical care setting in the US. The purpose of cEEG is primarily to detect nonconvulsive status epilepticus (NCSE) and secondarily, to evaluate the treatment of NCSE. It is difficult to diagnose NCSE in cEEG because of its variability. In the American Clinical Neurophysiology Society's Standardized Critical Care EEG Terminology 2012, EEG localization is placed under major term 1 and is classified as Lateralized (L), Generalized (G), Bilateral Independent (BI), and Multifocal (Mf). Morphology is placed under major term 2 and is classified as periodic, rhythmic, and spike-and-wave. Although there are no unequivocal criteria for the diagnosis of NCSE, the appearance of spatial and temporal changes in the EEG is essential for diagnosis.

Perioperative and Long-term Outcomes of Carotid Endarterectomy for Japanese Asymptomatic Cervical Carotid Artery Stenosis: A Single Institution Study

As the recently developed medical treatments for asymptomatic cervical carotid artery stenosis (ACCAS) have shown excellent stroke prevention, carotid endarterectomy (CEA) should be carried out for more selected patients and with lower complication rates and better long-term outcomes. We have performed CEA for Japanese ACCAS patients with a uniform surgical technique and strict perioperative management. In this study, we retrospectively investigated the perioperative complications and long-term outcomes of our CEA series. A total of 147 CEAs were carried out in 139 Japanese ACCAS patients. All patients were routinely checked for their cardiac function and high risk coronary lesions were preferentially treated before CEA. All CEAs were performed under general anesthesia using a shunt system. The postoperative cerebral blood flow was routinely measured under continued sedation to prevent postoperative hyperperfusion. The 30-day perioperative morbidity rate was 2.04%, including a perioperative stroke rate of 0.68%. There were no perioperative deaths. With regard to the long-term outcomes of the 134 followed-up patients, 9 patients were dead and 5 patients suffered from strokes, including 2 patients with ipsilateral hemispheric ischemia. The annual rates of death, all stroke and ipsilateral ischemic stroke were 1.15%, 0.64%, and 0.25%, respectively. These results showed that the perioperative morbidity and mortality rates of our CEAs were lower than those in the previous large trials. Furthermore, the long-term outcomes of this series were favorable to those reported in the latest medical treatment trials for ACCAS patients. CEA may be useful for preventing ischemic stroke in Japanese ACCAS patients.

Efficacy, safety, and outcomes in 17 pediatric cases treated with the free radical scavenger edaravone

SUBJECTS

Edaravone is a free radical scavenger with brain protection properties and is recommended by "The Japanese Guidelines for the Management of Stroke 2009" for administration to adult patients, in whom it has been shown to improve neurological deficits after cerebral infarction. However, its dosage and effects have not yet been established in children.

METHODS

Seventeen pediatric patients with cerebral ischemia were administered edaravone at a dose based on body weight from the standard dose given to adults. Functional outcomes were evaluated using mRS and PSOM (modified ranking scale and pediatric stroke outcome scale, respectively).

RESULTS

Immediate post-treatment results were mostly positive, with no liver or renal complications. In some cases, neurological symptoms markedly improved after the administration of edaravone.

CONCLUSIONS

The efficacy of edaravone has not yet been examined in pediatric patients. The results of the present study suggest that edaravone has potential in the treatment of children safely with promising results similar to those in adults.

Omnidirectional retractor-supporting ring as a new device for carotid endarterectomy

In carotid endarterectomy (CEA), the traditional retractors are often difficult to use because they tend to obstruct surgical manipulations, especially in the deep operative field on the rostral side. The authors have invented a new omnidirectional retractor-supporting ring (OD ring) to solve the problems of traditional retractors. The OD ring has an ellipsoid-shaped frame (major axis: 275 mm, minor axis: 192 mm) with 22 equally spaced outward protrusions. Rubber bands from which blunt mini-hooks are hung are twisted around the protrusions. The OD ring was placed on the operative area, and the skin edges were retracted by mini-hooks placed symmetrically. The hooks were moved gradually from the shallow to the deep operative field as surgical dissection continued to expose the carotid bifurcation and distal internal carotid artery (ICA). The OD ring was used in 158 consecutive CEAs in the authors' institute between July 2010 and October 2013. The OD ring provided a flatter surgical field and was less obstructive than traditional retractors, thereby facilitating surgical manipulation in the deep operative field such as at the distal ICA. Furthermore, because of its simpler shape, angiorrhaphy could be conducted more smoothly, with less tangled thread during closure of the arteriotomy. There were no technical complications related to the OD ring. As a new retractor system for CEA, the OD ring is less obstructive and provides a flatter surgical field than traditional retractors, thereby facilitating surgical manipulations in the deep operative field around the distal ICA.

Pulsed Laser-induced Liquid Jet System for Treatment of Sellar and Parasellar Tumors: Safety Evaluation

OBJECTIVE

The pulsed laser-induced liquid jet (LILJ) system is an emerging surgical instrument intended to assist both maximal removal of the lesion and functional maintenance through preservation of fine vessels and minimal damage to the surrounding tissue. The system ejects the minimum required amount of pulsed water through a handy bayonet-shaped catheter. We have already shown a significant increase in removal rate, in addition to a noteworthy reduction of intraoperative blood loss and procedure time in the treatment of large pituitary and skull base tumors in a single-institution series. The present study evaluated the safety of the system in multiple institutions.

METHODS

The study included 46 patients, 29 men and 17 women (mean age: 59.1 years) who underwent microsurgical/endoscopic resection of lesions in or in the vicinity of the pituitary fossa through the transsphenoidal approach between October 2011 and June 2012 at six institutions. The histologic diagnoses were pituitary adenoma (31 cases), meningioma (4), craniopharyngioma (3), cavernous angioma (2), and Rathke cyst cleft (1). Lesion volume ranged from 2.0 to 30.4 cm³ (mean: 3.7 cm³). Cavernous sinus invasion was observed in 11 cases and suprasellar extension in 29 cases.

RESULTS

Preservation of intralesional arteries (diameter: 150 µm) was achieved in all situations in > 80% of cases. Intended surgical steps were achieved except for some restrictions in motion due to the use of an optical quartz fiber. No complications occurred directly related to the use of the device.

CONCLUSIONS

The LILJ system can be used for safe removal of lesions in or in the vicinity of the pituitary fossa.