Intraoperative findings of abnormal muscle response for hemifacial spasm following botulinum neurotoxin treatment.

OBJECTIVE: This study aimed to investigate the effect of preoperative botulinum toxin (BTX) injection on intraoperative abnormal muscle response (AMR) in patients with hemifacial spasm (HFS). METHODS: A total of 104 patients (32 men, 72 women) who underwent microvascular decompression (MVD) for HFS were included in this study. A total of 62 patients without and 42 patients with preoperative BTX treatments were assigned to group A and group B, respectively. AMR recordings were obtained from the orbicularis oculi and mentalis muscles by stimulation of the marginal mandibular branch and zygomatic branch of the facial nerve, respectively. The intraoperative AMR monitoring findings and therapeutic effects were compared between groups A and B. RESULTS: The rates of the patients with unavailable AMRs recorded from the orbicularis oculi muscles in group B (38.1%) were significantly higher than those in group A (14.5%, p = 0.006). Moreover, in cases with over 4 times BTX injection, the recordings of AMR from the orbicularis oculi muscles were poorer than the cases with less BTX injection (p = 0.001). There were no significant differences in the rates of the patients with unavailable AMRs recorded from the mentalis muscles between the two groups. There were no significant differences in the surgical results obtained between the two groups. CONCLUSIONS: Preoperative BTX injections should be less than 4 times to ensure effective AMR monitoring. MVD using AMR monitoring is useful for patients with HFS who were previously treated by BTX as well as those who were not treated.

Choroid Plexus Papilloma in the Fourth Ventricle Associated with Pheochromocytoma: A Case Report.

We report for the first time a case of choroid plexus papilloma (CPP) of the fourth ventricle associated with adrenal pheochromocytoma. A large tumor was found in the fourth ventricle of a 24-year-old man who presented with symptoms of increased intracranial pressure due to obstructive hydrocephalus. A systemic search revealed that the patient also had an asymptomatic left adrenal tumor. Both tumors were resected. The pathological diagnosis of the brain tumor was CPP and that of the adrenal tumor was pheochromocytoma, both of which showed no pathological signs of malignancy. Genetic testing for von Hippel-Lindau disease was negative. There have been no reports of cases of CPP associated with pheochromocytoma. In this report, we discuss the relationship between both tumors.

Primary Intracranial Malignant Epidermoid with Multiple Metastases in Internal Organs: A Rare Autopsy Case.

Primary intracranial malignant epidermoids are rare, with most cases developing from a pre-existing benign epidermoid cyst. We report a case involving a rare autopsy finding of a primary intracranial malignant epidermoid in the brainstem with cerebellopontine angle (CPA) involvement. A 53-year-old woman with double vision was diagnosed with right abducens palsy. At her visit to our hospital 3 months after the onset of the first symptom, she presented left hypoglossal nerve paralysis and truncal ataxia in addition to right abducens palsy. Magnetic resonance imaging (MRI) revealed a mass lesion (2-cm long and 3-cm thick) in the left CPA that exhibited gadolinium enhancement. Moreover, gadolinium-enhanced magnetic resonance imaging (MRI) revealed abnormal multiple brainstem and supratentorial mass lesions with partial enhancement. Whole-body computed tomography failed to identify any possible primary lesion. Following a tentative diagnosis of an epidermoid cyst with an assumption that the tumor was highly aggressive, we performed subtotal surgical resection of the CPA tumor. Histological findings revealed a malignant epidermoid in the CPA lesion. Although the patient underwent radiation and chemotherapy after the surgical resection, she died of respiratory failure 10 months after the onset of symptoms. Herein, we report the rare clinical course and autopsy data, and discuss the characteristic features of this rare condition.

[Posterior Quadrantectomy for Infant with Refractory Epilepsy:A Case Report].

We present the case of an 11-month-old girl with linear nevus sebaceous syndrome who underwent posterior quadrantectomy(PQ)for intractable epilepsy due to cortical dysplasia extending from the temporal, parietal, and occipital lobes in the right hemisphere. Epileptic spasms started at 4 months after birth, and the frequency of her seizures gradually increased to 10 episodes per day. Electroencephalograms in the interictal periods showed hypsarrhythmia. Magnetic resonance imaging(MRI)suggested cortical dysplasia in the right temporal, parietal, and occipital lobes. Ictal single-photon emission computed tomography revealed increased cerebral blood flow in similar areas as the cortical dysplasia suggested on MRI. Several antiepileptic drugs were administered to control the epileptic spasms, without success. In addition, her developmental delay gradually became evident. Because the epileptic foci extended into the posterior region of the right hemisphere, we did not execute a focused resection, but performed a PQ. The epileptic spasms completely disappeared after surgery and her developmental delay gradually improved. Early surgical intervention via PQ is useful in patients with drug-resistant epilepsy in whom the epileptic foci have extended into the temporal, parietal, and occipital lobes. This intervention not only controls intractable seizures but also helps to facilitate normal development.

Malignant peripheral nerve sheath tumor of the trigeminal nerve: clinicopathologic features in a young adult patient.

Malignant peripheral nerve sheath tumors (MPNSTs) arising from cranial nerves are rare and usually affect adults. Here we report the clinicopathologic features of a young adult patient with a trigeminal nerve MPNST, in whom another tumor involving the oculomotor nerve on the contralateral side was evident. The patient, an 18-year-old woman, had suffered recurrent paroxysmal sharp stabbing pain over her cheek and forehead on the right side for 1 month. A brain MRI study disclosed a mass, 35 mm in diameter, in the right Meckel's cave, and another mass, 10 mm in diameter, involving the intracranial portion of the left oculomotor nerve. Following gadolinium administration, the former and latter tumors exhibited strong and weak enhancement, respectively. The patient had no clinical stigmata characteristic of neurofibromatosis type 1. Following a tentative diagnosis of schwannoma, total resection of the trigeminal nerve tumor was performed. Histologically, the tumor consisted of highly cellular, spindle-shaped cells arranged in a fascicular pattern, with occasional mitotic figures, nuclear pleomorphism and necrosis. Immunohistochemically, the tumor cells showed variable intensities and frequencies of reactivity for S-100 protein, myelin basic protein, CD34, podoplanin and p53, but no reactivity for Smarcb1. Thus, the tumor exhibited features of MPNST. This case appears to provide information that is useful for accurate diagnosis and surgical planning in patients with bilateral or multiple cranial nerve tumors.

Lymphoplasmacyte-rich meningioma: a convexity mass with regional enhancement in the adjacent brain parenchyma.

Lymphoplasmacyte-rich meningioma (LPM) is a rare, benign variant of meningioma, characterized by massive inflammatory cell infiltration and a variable proportion of meningothelial tumorous elements. Here we report the clinicopathological features of an LPM located at the right frontal convexity in a 37-year-old woman. The patient had suffered an initial generalized tonic-clonic seizure when she was 32 weeks pregnant. The lesion exhibited low intensity on T1-weighted MRI and high intensity on T2-weighted images, with surrounding parenchymal edema. The mass exhibited gadolinium enhancement with dural tail signs. Moreover, multiple foci of linear enhancement spreading through the sulci and into the nearby brain parenchyma were evident. At 1 month after parturition, en bloc removal of the mass, the attached dura mater and adjacent brain tissue was performed. Histologically, the mass located in the subdural space was composed of a mixture of B- and T-lymphocytes and plasma cells. Within the mass, multiple small lobules of meningothelial cells showing immunoreactivity for epithelial membrane antigen and vimentin were observed. The inflammatory cells had also infiltrated the subarachnoid and Virchow-Robin spaces, and the dura mater. The cerebral cortex showed ischemic changes, but no tumor cell invasion. On the basis of these histological features, the lesion appeared to be LPM with an inconspicuous meningothelial component and extensive inflammatory infiltration. This case appears to provide useful information on the pathogenesis of this variant.

Trigeminal neuralgia associated with the specific bridging pattern of transverse pontine vein: diagnostic value of three-dimensional multifusion volumetric imaging.

OBJECTIVES: We report the specific bridging pattern of a transverse pontine vein (TPV) associated with trigeminal neuralgia (TN), which was evaluated by 3-dimensional (3D) multifusion volumetric imaging (MFVI). METHODS: In 3 cases with TN (V1 or V1-2 territory), constructive interference in steady state (CISS) imaging confirmed no arterial compression but indicated a vein draining into Meckel's cave. Virtual endoscopic (VE) analysis for CISS images and 3D MFVI (in 2 cases) including venous information was obtained by a multidetector row computed tomography (MDCT) system. Additionally, we investigated the bridging pattern of veins around Meckel's cave on 3D MFVI of 50 cerebellopontine angle (CPA) regions without any lesions. RESULTS: In all 3 patients, VE of CISS or 3D MFVI identified a bridging vein from the TPV causing the focal deformity of the trigeminal nerve near Meckel's cave. All those patients achieved a pain-free state after surgically coagulating and cutting the vein. In investigating 3D MFVI of 50 CPA regions, this type of the bridging vein was found in 4 (8%) including the presented 2 cases. CONCLUSIONS: The specific bridging pattern of the TPV draining into Meckel's cave can be associated with TN. The 3D MFVI analysis using venous information obtained by MDCT was useful to evaluate surgical anatomy including the offending vein which can be missed.

Unstable stenosis of the internal carotid artery caused by a craniofacial nail-gun injury-case report-.

A 30-year-old carpenter suffered accidental piercing of his jaw by a 3-inch nail from a nail gun. No neurological deficits were found on admission. Computed tomography showed that the tip of the nail had reached the foramen lacerum. Cerebral angiography revealed severe stenosis at the C(4) portion of the left internal carotid artery (ICA) and marked decrease in the flow of the distal ICA. He had developed right hemiparesis and sensory aphasia by the following morning. T(2)-weighted and fluid-attenuated inversion recovery magnetic resonance imaging showed a focal hyperintense signal in the left central region indicating cerebral infarction. Repeat angiography demonstrated that the antegrade blood flow from the occluded point on the admission day had partially resumed, and endovascular trapping of the ICA was successfully carried out. The nail was then removed safely without problematic bleeding. The patient suffered no additional deficit, and his sensory aphasia and right hemiparesis gradually improved. The fluctuating blood flow through the unstable stenosis of the ICA related to nail movement possibly caused the delayed cerebral infarction. To avoid the occurrence of such events, rapid treatment after necessary investigations is recommended in patients with craniofacial penetrating injuries that affect the ICA.

Etiopathological factors related to hydrocephalus associated with vestibular schwannoma.

OBJECTIVE: We retrospectively analyzed various clinical factors to determine whether or not these factors are etiopathologically related to the development of hydrocephalus in patients with vestibular schwannomas. METHODS: There were 68 patients (29 men, 39 women) in this study who underwent resection of a vestibular schwannoma. The age at the time of surgery ranged from 19 to 76 years (mean age, 51.4 yr). The maximum diameter of the tumor in the cerebellopontine cistern ranged from 0 (localized within the internal auditory canal) to 56 mm (mean, 32.0 +/- 12.9 mm). Cerebrospinal fluid (CSF) protein concentration in the cerebellomedullary cistern was measured intraoperatively in all patients. RESULTS: Sixteen (23.5%) of the 68 patients exhibited radiographic evidence of hydrocephalus. Univariate analysis of various factors revealed that both tumor size and CSF protein concentration were positively related to development of hydrocephalus (P < 0.05 and P < 0.01, respectively). However, in multiple logistic regression analysis, only the CSF protein concentration was predictive for development of hydrocephalus (P = 0.022). There was a trend toward increased CSF protein concentration in patients with a large tumor (> or = 40 mm) compared with those with a small tumor (< 40 mm) (P = 0.06). CONCLUSION: A high CSF protein concentration in fluid from the cerebellomedullary cistern is one of the most important factors contributing to hydrocephalus associated with vestibular schwannoma. It is important to judge whether or not any further treatment is required for hydrocephalus, in addition to tumor resection, especially in patients with communicating hydrocephalus.

[Delayed brain abscess after penetrating transorbital injury].

We report a case of brain abscess caused by a penetrating head injury that occurred 9 years earlier. A 14-year-old girl presenting with fever, headache, and stiff neck was admitted to our hospital. She was diagnosed with aseptic meningitis and treated conservatively. Seven days after admission she became stuporous and showed left hemiparesis. Computed tomography (CT) revealed two ring-enhancing masses with perifocal edema in the right frontal lobe. We diagnosed brain abscess and performed right fronto-temporal decompressive craniectomy and stereotactic aspiration, followed by systemic antibiotic therapy. Post-surgery bone window CT revealed a well-defined, low-density foreign body passing from the left orbita to the right frontal lobe through the ethmoid sinus. We learned that the patient had been struck with a plastic chopstick in the left medial eyelid at the age of 5 years. No particular symptoms developed during the following 9 years. After the cerebral edema had diminished over the next 10 days, a second surgery was performed to remove the residual chopstick, repair the fistula at the base of the skull, and perform cranioplasty. The patient was discharged with only slight hyposmia after a 4-week course of antibiotics. This case showed that it is necessary to remove a residual foreign body and to close the dural fistula if there is a possibility of recurrent central nervous system infection. When a child presents with brain abscess, previous penetrating head injury should be considered.

[Abnormal muscle response monitoring during microvascular decompression for hemifacial spasm and long term results].

OBJECTIVE: There is some debate over the reliability of intraoperative abnormal muscle response (AMR) monitoring as an indicator of postoperative long-term outcome in patients with hemifacial spasm (HFS). We investigated whether AMR findings obtained during microvascular decompression reflect postoperative long-term outcome. MATERIAS AND METHODS: Subjects were 51 HFS patients who underwent AMR monitoring during surgery. AMR recordings were obtained from the mentalis muscle by electrical stimulation of the temporal branch of the facial nerve and from the orbicularis oculi muscles by stimulation of the marginal mandibular branch. Postoperative follow-up was more than 5 years (range 61-118 months, mean 87 months). RESULTS: In 37 patients, AMR disappeared after vascular decompression. Among those patients, only one presented with spasm at the final follow-up examination. In 6 of 7 patients with AMR that disappeared early before the completion of decompression, hemifacial spasm resolved completely. Five of six patients in whom AMR still remained but with decreased amplitude at the end of surgery experienced complete resolution. CONCLUSIONS: Our findings suggest that intraoperative cessation including prior to decompression or decreased amplitude of AMR at the end of surgery indicates a high likelihood of postoperative long-term relief of HFS. We believe that intraoperative AMR monitoring is useful in MVD surgery for HFS.

Transcranial imaging of audiogenic epileptic foci in the cortex of DBA/2J mice.

Exposure to intense sound stimuli induces audiogenic seizures in DBA/2J mice. We investigated cortical activities during sound stimulation using flavoprotein fluorescence imaging. Most DBA/2J mice had seizures during intense sound stimulation, with more than half surviving after seizures. Surviving mice were anesthetized with urethane (1.6 g/kg, intraperitoneal), and the skull was exposed and then covered with clear resin. More than 3 days after surgery, the mice were lightly anesthetized with urethane (0.8 g/kg) and cortical activities during intense sound stimulation were visualized. Focal responses appeared near the somatosensory cortex together with spike activities localized in the response area. These findings indicate that epileptic foci of audiogenic seizure are formed in the cortex of DBA/2J mice.

Monitoring of the lateral spread response in the endovascular treatment of a hemifacial spasm caused by an unruptured vertebral artery aneurysm. Case report.

The lateral spread response (LSR) is used in the electrophysiological diagnosis of a hemifacial spasm or for monitoring during microvascular decompression. The authors used LSRs for intraoperative monitoring during endovascular surgery in a rare case of vertebral artery (VA) aneurysm that caused intractable hemifacial spasm. A 49-year-old woman presented with a right hemifacial spasm that had persisted for 9 months. No other clinical symptom was observed. Vertebral artery angiography revealed a saccular aneurysm of the right VA. Magnetic resonance (MR) imaging demonstrated that the aneurysm was compressing the root exit zone of the right facial nerve. Endovascular treatment of the VA aneurysm was performed while monitoring the patient's LSRs. During occlusion of the VA at sites distal and proximal to the aneurysm, the LSRs temporarily disappeared and then reappeared with a higher amplitude than those measured preceding their disappearance. The hemifacial spasm alleviated gradually and disappeared completely 6 months after treatment. The LSRs changed in parallel with the improvement in the patient's hemifacial spasms and eventually disappeared. No recurrence of symptoms has been noticed as of 18 months postoperatively. This is the first report of the use of LSR monitoring during endovascular surgery for an intracranial aneurysm that causes hemifacial spasm. Intraoperative and postoperative changes in the LSRs provided useful information regarding the pathophysiology of hemifacial spasm.

Short-term plasticity visualized with flavoprotein autofluorescence in the somatosensory cortex of anaesthetized rats.

In the present study, short-term plasticity of somatosensory neural responses was investigated using flavoprotein autofluorescence imaging in rats anaesthetized with urethane (1.5 g/kg, i.p.) Somatosensory neural activity was elicited by vibratory skin stimulation (50 Hz for 1 s) applied on the surface of the left plantar hindpaw. Changes in green autofluorescence (lambda = 500-550 nm) in blue light (lambda = 450-490 nm) were elicited in the right somatosensory cortex. The normalised maximal fluorescence responses (deltaF/F) was 2.0 +/- 0.1% (n = 40). After tetanic cortical stimulation (TS), applied at a depth of 1.5-2.0 mm from the cortical surface, the responses elicited by peripheral stimulation were significantly potentiated in both peak amplitude and size of the responsive area (both P < 0.02; Wilcoxon signed rank test). This potentiation was clearly observed in the recording session started 5 min after the cessation of TS, and returned to the control level within 30 min. However, depression of the responses was observed after TS applied at a depth of 0.5 mm. TS-induced changes in supragranular field potentials in cortical slices showed a similar dependence on the depth of the stimulated sites. When TS was applied on the ipsilateral somatosensory cortex, marked potentiation of the ipsilateral responses and slight potentiation of the contralateral responses to peripheral stimulation were observed after TS, suggesting the involvement of commissural fibers in the changes in the somatosensory brain maps. The present study clearly demonstrates that functional brain imaging using flavoprotein autofluorescence is a useful technique for investigating neural plasticity in vivo.

Dynamic imaging of somatosensory cortical activity in the rat visualized by flavoprotein autofluorescence.

We used autofluorescence of mitochondrial flavoproteins to image cortical neural activity in the rat. Green autofluorescence in blue light was examined in slices obtained from rat cerebral cortex. About half of the basal autofluorescence was modulated by the presence or absence of O2 or glucose in the medium. Repetitive electrical stimulation at 20 Hz for 1 s produced a localized fluorescence increase in the slices. The amplitude of the increase was 27 +/- 2 % (mean +/- S.D., n = 35). Tetrodotoxin or diphenyleneiodonium, an inhibitor of flavoproteins, blocked the autofluorescence responses. The autofluorescence responses were not observed in slices perfused with calcium-, glucose- or O2-free medium. In the primary somatosensory cortex of rats anaesthetized with urethane (1.5 g kg-1, I.P.), an activity-dependent increase in autofluorescence of 20 +/- 4 % (n = 6) was observed after electrical cortical stimulation at 100 Hz for 1 s, and an increase of 2.6 +/- 0.5 % (n = 33) after vibratory skin stimulation at 50 Hz for 1 s applied to the plantar hindpaw. These responses were large enough to allow visualization of the neural activity without having to average a number of trials. The distribution of the fluorescence responses after electrical or vibratory skin stimulation was comparable to that of the cortical field potentials in the same rats. The fluorescence responses were followed by an increase in arterial blood flow. The former were resistant to an inhibitor of nitric oxide synthase, while the latter was inhibited. Thus, activity-dependent changes in the autofluorescence of flavoproteins are useful for functional brain imaging in vivo.

Hemifacial spasm associated with an ependymal cyst in the cerebellopontine angle. Case report.

No previous case of hemifacial spasm associated with an ependymal cyst has been reported in the literature. In this article the authors report the first case in which hemifacial spasm accompanied an ipsilateral cerebellopontine angle ependymal cyst in a 27-year-old woman. Cyst fenestration and arterial decompression of the facial nerve at the root exit zone resulted in complete resolution of the patient's symptoms. A histopathological study including immunohistochemical methods identified an ependymal cyst.

Lateral spread response elicited by double stimulation in patients with hemifacial spasm.

In patients with hemifacial spasm (HFS), a lateral spread response (or abnormal muscle response) is recorded from facial muscles after facial nerve stimulation. The origin of this response is not completely understood. We studied the lateral spread responses elicited by double stimulation in 12 patients with HFS during microvascular decompression. The response was recorded from the mentalis muscle by electrical stimulation of the temporal branch of the facial nerve or from the orbicularis oculi muscles by stimulation of the marginal mandibular branch. The interstimulus intervals (ISIs) of double stimulation ranged from 0.5 to 7.0 ms. R1 was defined as the response elicited by the first stimulus, and R2 as the response elicited by the second stimulus. R1 had a constant latency and amplitude regardless of the ISI, whereas R2 appeared after a fixed refractory period without facilitation or depression in a recovery curve of latency and amplitude. From these findings, we consider that the lateral spread response is due to cross-transmission of facial nerve fibers at the site of vascular compression rather than arising from facial nerve motor neurons.

[Presurgical functional mapping of the sensorimotor area using evoked magnetic fields].

In the present study, we evaluated the usefulness of magnetoencephalography (MEG) for presurgical identification of not only the central sulcus by somatosensory evoked magnetic fields (SEFs), which is a well-known, reliable technique, but also the primary hand motor area by movement-related cerebral magnetic fields (MRCFs). Subjects were 10 patients with brain tumor (6 glial tumors, 3 cavernous angiomas, and 1 metastatic tumor) around the sensorimotor area. Identification of the central sulcus by SEF responses to multiple sites of stimulation (median nerve, tibial nerve, thumb, and lower lip) was performed in all patients, and identification of the hand motor area by MRCF responses to the index finger extension task was made in 9. All MEG data were superimposed on sectional or three-dimensional magnetic resonance (MR) images. The central sulcus was clerAly identified by SEFs in all patients, even in 5 whose MR images showed severe distortion, and the primary hand motor area was identified by MRCFs in 6 of 9 patients. The central sulcus and primary motor area identified by MEG were confirmed by cortical recording of somatosensory evoked potentials in response to median nerve stimulation in 7 patients and motor evoked potentials in response to direct cortical stimulation in 5. All patients underwent tumor removal guided by functional mapping by MEG and experienced no surgical complications. In conclusion, MEG is a useful tool in presurgical functional mapping of the sensorimotor area. This is the first report of a case in which identification of the hand motor area by MRCFs was used in a clinical setting.