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ABSTRACT: To establish the validity and utility of motor-evoked potential (MEPs) monitoring for skull base tumor resection, we explored the relationship between MEP monitoring results and postoperative motor function.
MEPs were successfully monitored during 76 operations in 68 patients with a high risk of motor morbidity. MEP monitoring data were correlated with perioperative clinical motor function.
MEPs remained stable in 56 operations (73.7%), and no postoperative motor deterioration was observed. Transient or permanent deterioration of MEPs (<50% of the initial amplitude before surgery) occurred in 20 operations (26.3%). This deterioration was reversible after intervention in seven cases (9.2%). Irreversible deterioration in MEPs was seen in 13 cases (17.1%). In five cases, the final amplitude was greater than 10%. Two of these patients experienced transient loss of MEPs and moderate to severe hemiparesis. Both patients showed full recovery within 6 months after the operation. The other three patients experienced no postoperative worsening of motor function. The final MEP amplitude was less than 10% in the other eight patients, including five with permanent MEP loss. All of these patients experienced severe postoperative motor dysfunction. Recovery of motor function was worse in most participants in this group compared with those in the other groups.
Intraoperative MEP monitoring is a valid indicator of pyramidal tract pathway function for skull base tumor surgery.
Acta Neurochirurgica 06/2011; 153(6):1191-200; discussion 1200. · 1.52 Impact Factor
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ABSTRACT: A female baby was born at 37 weeks and 6 days gestation by vaginal delivery with omphalocele, exstrophy of the cloaca, and imperforate anus, indicating the presence of OEIS complex, a rare combination of defects consisting of omphalocele (O), exstrophy of the cloaca (E), imperforate anus (I), and spinal deformity (S), associated with lumbosacral lipoma. The most common associated spinal deformity is terminal myelocystocele, and spinal lipoma is rare. Constructive interference in steady-state magnetic resonance imaging clearly revealed double lipomas, a dorsal-type lipoma, located dorsal to the low-lying conus medullaris, and a filar-type lipoma, revealed by a thickened and fatty filum terminale. After recovery from abdominogenital repairs, debulking of the dorsal-type lipoma and untethering of the spinal cord by sectioning of the filar-type lipoma were performed at the age of 14 months. Neurosurgical treatment for occult spinal dysraphism should be undertaken after recovery from the initial series of major abdominogenital procedures.
Neurologia medico-chirurgica 10/2009; 49(10):487-90. · 0.61 Impact Factor
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ABSTRACT: A 49-year-old man presented with a rare case of cerebellar hemangioblastoma manifesting as only hearing disturbance. He had suffered from hearing difficulty in the right ear for a few months. Magnetic resonance imaging revealed a cystic mass lesion with an internal fluid level and surrounding flow voids in the right cerebellopontine (CP) angle. Cerebral angiography disclosed a vascular-rich tumor fed by both the superior cerebellar and anterior inferior cerebellar arteries. En bloc resection of the tumor was planned under a preoperative diagnosis of cerebellar hemangioblastoma. The tumor protruded into the CP cistern and compressed cranial nerve VIII. The feeding arteries were meticulously coagulated and the tumor was successfully removed. The histological diagnosis was hemangioblastoma. After the operation, the patient's hearing acuity improved dramatically. Cerebellar hemangioblastoma should be considered in the differential diagnosis of CP angle tumors associated with hearing disturbance.
Neurologia medico-chirurgica 09/2009; 49(9):418-20. · 0.61 Impact Factor
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ABSTRACT: We described three cases with hemorrhagic complication during simultaneous multi-track microelectrode recording (MER) for stereotactic implantation of a subthalamic nucleus electrode. Although preoperative planning with gadolinium-enhanced T1-weighted MR images is recommended to prevent the occurrence of intracerebral hemorrhage, it should be noted that the danger from cerebral vasculatures is still underestimated. Multiple nonspecific white matter hyperintensities and asymptomatic lacunar infarcts may be suspected as potential risk factors, so, it is suggested that the number of MER penetrations should be restricted in such cases.
No shinkei geka. Neurological surgery 07/2009; 37(6):559-64. · 0.13 Impact Factor
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Yasushi Miyagi,
Tsuyoshi Okamoto,
Takato Morioka,
Shozo Tobimatsu,
Yoshitaka Nakanishi,
Kazuyuki Aihara,
Kimiaki Hashiguchi,
Nobuya Murakami, Fumiaki Yoshida,
Kazuhiro Samura,
Shinji Nagata,
Tomio Sasaki
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ABSTRACT: Spectral analysis of local field potential (LFP) recorded by deep brain stimulation (DBS) electrode around the subthalamic nucleus (STN) in patients with Parkinson's disease was performed.
The borders of the STN were determined by microelectrode recording. The most eligible trajectory for the sensorimotor area of the STN was used for LFP recording while advancing the DBS electrode.
The low-frequency LFP power (theta- to beta-band) increased from a few millimeters above the dorsal border of the STN defined by microelectrode recording; however, the low-frequency power kept the same level beyond the ventral border of the STN. Only high beta-power showed close correlation to the dorsal and ventral borders of the STN.
A spectral power analysis of LFP recording by DBS electrode helps with the final confirmation of the dorsal and ventral borders of the STN of Parkinson's disease in DBS implantation surgery.
Stereotactic and Functional Neurosurgery 07/2009; 87(4):211-8. · 1.85 Impact Factor
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ABSTRACT: Tinnitus is one of the most common symptoms in patients with vestibular schwannomas (VSs), but the effect of surgery on this symptom has not been fully evaluated. The aim of this study was to define the effect on tinnitus of tumor removal, cochlear nerve resection, and useful hearing preservation in patients with VSs.
The authors retrospectively analyzed the status of tinnitus before and after surgery in 242 patients with unilateral VSs who underwent surgery via the retrosigmoid lateral suboccipital approach.
Of 242 patients, 171 (70.7%) complained of tinnitus before surgery; the symptom disappeared in 25.2%, improved in 33.3%, remained unchanged in 31.6%, and worsened in 9.9% of these cases after tumor removal. In the 171 patients with preoperative tinnitus, the cochlear nerve was resected in 85 (49.7%) and preserved in 86 (50.3%), but there was no significant difference in the incidence of postoperative tinnitus between these 2 groups (p = 0.293). In the 71 patients without preoperative tinnitus, the symptom developed postoperatively in 6 cases (8.5%). Among those without preoperative tinnitus, the cochlear nerve was resected in 45 cases (63.4%) and tinnitus appeared postoperatively in 3 (6.7%). The authors also analyzed the association between postoperative tinnitus and useful hearing preservation, but could not find any statistically significant association between the 2 factors (p = 0.153).
Tumor removal via the retrosigmoid lateral suboccipital approach may provide some chance for improvement of tinnitus in patients with VSs; however, neither cochlear nerve resection nor useful hearing preservation affects the postoperative development of tinnitus.
Journal of Neurosurgery 06/2009; 112(1):152-7. · 2.96 Impact Factor
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Fumiaki Yoshida,
Yasushi Miyagi,
Junji Kishimoto,
Takato Morioka,
Nobuya Murakami,
Kimiaki Hashiguchi,
Kazuhiro Samura,
Nobutaka Sakae,
Ryo Yamasaki,
Minako Kawaguchi,
Tomio Sasaki
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ABSTRACT: Among the neuropsychiatric symptoms in Parkinson's disease (PD) patients, hallucination can result from the disease itself or medical treatment. Hallucination associated with subthalamic nucleus stimulation (STN-DBS) has been reported; however, it is still unclear whether PD patients with a history of hallucination are appropriate candidates for STN-DBS or not.
We investigated the effect of STN-DBS on preexisting hallucination associated with advanced PD.
Eighteen STN-DBS patients were investigated retrospectively. The severity of hallucination was assessed by the thought disorder score on the Unified Parkinson's Disease Rating Scale (UPDRS, part 1-item 2) in the patients' interviews; the score 6 months after the initiation of STN-DBS was compared with the highest score throughout the preoperative history and the score 2 weeks before surgery.
Hoehn-Yahr stage and motor score (UPDRS part 3) were significantly improved following STN-DBS. Six months after the initiation of STN-DBS, the severity of hallucination, assessed by thought disorder score, did not increase, but rather decreased compared with the preoperative level (p < 0.05 by McNemar's test). The daily levodopa equivalent dose was increased in 2 patients without the development of hallucination. On the other hand, anti-parkinsonian drugs were totally withdrawn in 1 patient, but without improvement of hallucination.
Our findings indicate that STN-DBS surgery does not always lead to deterioration of preexisting hallucination in PD. In advanced PD, hallucination involves a multifactorial pathogenesis and a history of hallucination is not a contraindication to STN-DBS surgery.
Stereotactic and Functional Neurosurgery 02/2009; 87(1):45-9. · 1.85 Impact Factor
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ABSTRACT: We report an operated case with terminal myelocystocele and holocord hydrosyringomyelia (syrinx). The patient exhibited a subcutaneous mass at the right lumbosacral region with multiple anomalies including scoliosis and hyperdactylia of the right foot and systemic disease such as hydronephroureter. Neurological examination revealed palsy of the left diaphragm, and left upper and right lower limbs. Constructive interference in steady-state (CISS) images demonstrated a terminal myelocystocele with a huge syrinx extending to the medulla. The curvilinear reconstruction of the CISS sequence depicted continuous cystocele and whole syrinx. At day 37, sac excision and untethering of the spinal cord were performed. The caudal part of the central canal was opened to the subarachnoid space (terminal ventriculostomy), resulting in a slight improvement of limb palsy and shrinkage of the holocord syrinx. CISS imaging is useful to detect the complicated pathology, and terminal ventriculostomy should be performed to improve associated syrinx.
Pediatric Neurosurgery 02/2009; 44(6):509-12. · 0.70 Impact Factor
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ABSTRACT: The advancement of magnetic resonance (MR) imaging technology has revealed that intracranial venous anomalies, such as vertical embryonic positioning of the straight sinus (VEP of SS), are associated with atretic parietal cephaloceles. However, the precise anatomical relationships among the venous anomalies, superior sagittal sinus (SSS), cistern, and cephalocele have not been demonstrated. We compared the imaging features of conventional MR images and high-resolution 3-dimensional (3-D) MR images, such as Fourier-transformation-constructive interference in steady-state (CISS) images and T2-weighted reversed (T2R) images obtained on a 3-T MR machine.
Three patients ranging in age from 1 to 18 years, with midline subscalp lesions, participated in this study. In two cases, the lesions were surgically excised and subjected to pathological examination.
In two children, 3-D MR images more clearly demonstrated anomalous veins, including bilateral internal cerebral veins, the great vein of Galen and the vertical position of the straight sinus in the falx, extending superiorly within the CSF tract in the posterior interhemispheric fissure. While the vertical straight sinus drained into the SSS, the CSF tract maintained a position posterior to the anomalous veins, ran through the SSS and extended to the skull defect. In one patient, ascending positioning of the anomalous vein from the inferior sagittal sinus to the SSS in the CSF space was observed; this could not be depicted on conventional MR images.
Detailed findings of the venous anomalies on 3-D MR images provide clues to the diagnosis of atretic cephalocele.
Child s Nervous System 11/2008; 25(3):309-15. · 1.54 Impact Factor
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ABSTRACT: The authors analyzed the tumor capsule and the tumor-nerve interface in vestibular schwannomas (VSs) to define the ideal cleavage plane for maximal tumor removal with preservation of facial and cochlear nerve functions.
Surgical specimens from 21 unilateral VSs were studied using classical H & E, Masson trichrome, and immunohistochemical staining against myelin basic protein.
The authors observed a continuous thin connective tissue layer enveloping the surfaces of the tumors. Some nerve fibers, which were immunopositive to myelin basic protein and considered to be remnants of vestibular nerve fibers, were also identified widely beneath the connective tissue layer. These findings indicated that the socalled "tumor capsule" in VSs is the residual vestibular nerve tissue itself, consisting of the perineurium and underlying nerve fibers. There was no structure bordering the tumor parenchyma and the vestibular nerve fibers. In specimens of tumors removed en bloc with the cochlear nerves, the authors found that the connective tissue layer, corresponding to the perineurium of the cochlear nerve, clearly bordered the nerve fibers and tumor tissue.
Based on these histological observations, complete tumor resection can be achieved by removal of both tumor parenchyma and tumor capsule when a clear border between the tumor capsule and facial or cochlear nerve fibers can be identified intraoperatively. Conversely, when a severe adhesion between the tumor and facial or cochlear nerve fibers is observed, dissection of the vestibular nerve-tumor interface (the subcapsular or subperineurial dissection) is recommended for preservation of the functions of these cranial nerves.
Journal of Neurosurgery 10/2008; 110(4):648-55. · 2.96 Impact Factor
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ABSTRACT: CASE REPORT: We present a female baby with a human tail associated with congenital dermal sinus (CDS) at the caudal site of the tail. Magnetic resonance (MR) images with constructive interference in steady-state (CISS) sequencing clearly demonstrated a lumbosacral lipoma of caudal type, contiguous with the dermal sinus tract and not with the human tail. At 3 months old, the tail was surgically removed. The dermal sinus tract and contiguous lipoma were also resected, and untethering of the spinal cord was performed. Although both the human tail and CDS are frequently associated with spina bifida occulta, coexistence of the tail and CDS is exceedingly rare. CISS-MRI is useful for demonstrating the precise anatomical relationship between these complicated pathologies.
Child s Nervous System 09/2008; 25(1):137-41. · 1.54 Impact Factor
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ABSTRACT: We report the case of a 35-year-old woman who developed right medial temporal lobe epilepsy associated with misplacement of a ventricular shunting catheter in the apex of the right temporal lobe. At 8 years of age, the patient had undergone total removal of a cerebellar astrocytoma and placement of a Torkildsen's ventriculo-cisternal shunt for obstructive hydrocephalus. Although the postoperative course was uneventful, she developed medically intractable psychomotor seizures with secondary generalization at 24 years of age. CT revealed that the tip of the shunting catheter was misplaced in the apex of the right temporal lobe, through the posterior and inferior horn of the right lateral ventricle. Intraoperative electrocorticography revealed frequent paroxysmal activity in the hippocampus, so hippocampectomy as well as removal of the shunting catheter was performed. Postoperatively, the patient became seizure-free, and pathological examination revealed hippocampal sclerosis.
Journal of Clinical Neuroscience 09/2008; 15(8):939-42. · 1.25 Impact Factor
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ABSTRACT: OEIS complex has been described as a combination of defects consisting of omphalocele (O), exstrophy of the cloaca (E), imperforate anus (I), and spinal defects (S). As the first three defects are life-threatening and treated on a priority basis, neurosurgical intervention for spinal defects is deferred until recuperation from abdominogenital repair. However, the best timing for neurosurgical operation has not been precisely described.
We reviewed our neurosurgical management of three cases (case 1: myelomeningocele; cases 2 and 3: terminal myelocystocele). At 2-6 (3.6 on average) months after birth, neurosurgical procedures, including reduction of the size of the lumbosacral cystic lesion and untethering of the spinal cord, were performed.
During this period, the patients' weights increased from 1,911 to 3,368 g on average, and the lumbosacral cystic lesion was markedly enlarged. In all cases, no neurological deterioration was seen, and ventriculoperitoneal shunt was not indicated.
Thus, neurosurgical procedures can be performed in patients weighing 3-4 kg and/or at an age of 3 months, after confirming recuperated conditions from abdominogenital repair. Careful observation should be made of the size of the lumbosacral cystic lesion and neurological deterioration.
Child s Nervous System 07/2008; 24(6):723-9. · 1.54 Impact Factor
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ABSTRACT: CASE REPORT: Focal cortical dysplasia (FCD) with calcification is rare. We presented a 13-year-old epileptic patient with FCD and calcification in the left frontal lobe. At age 24, the FCD lesion and the surrounding epileptogenic cortex and underlying subcortex were removed after chronic subdural electrode recording. Histological examination showed that the calcified lesion was not independent of the FCD lesion but located in the subcortical area of the FCD lesion. A neoplastic nature was ruled out for the lesion. DISCUSSION: The pathophysiological mechanism involved in the coexistence of FCD and calcification is discussed.
Child s Nervous System 06/2008; 24(5):619-22. · 1.54 Impact Factor
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ABSTRACT: Bursal cysts (bursitis) are attributed to repeated microtrauma of the connective tissue around the synovial joint and are rare in the coccygeal region.
A 10-year-old boy had a subcutaneous tumor at the midline of the buttock. He could not walk and slid himself in a seated position because of psychomotor retardation. MR images showed a cystic lesion overlying the coccygeal bone, the intensity of which was identical to cerebrospinal fluid (CSF). Although meningocele was suspected, constructive interference in steady-state (CISS) MR images clearly depicted a discontinuity between the cyst and CSF space.
It was conceivable that repeated friction between the coccygeal bone, which projected posteriorly, and overlying subcutaneous tissue during movement resulted in the formation of a bursal cyst. In addition to total removal of the cyst, the coccygeal bone was planed away to prevent friction. We should keep this rare clinical entity in mind in cases that appear to be sacrococcygeal meningocele.
Child s Nervous System 05/2008; 24(4):533-5. · 1.54 Impact Factor
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ABSTRACT: CASE REPORT: It is well known that magnetic resonance imaging (MRI) findings of focal cortical dysplasia (FCD) can change with maturation of myelination. In this paper, we report a patient with intractable epilepsy and negative MRI at the age of 2.5 years, after completion of myelination. Follow-up MRI at the age of 6 years revealed typical FCD findings in the right frontal lobe. During these 3.5 years, electroencephalogram (EEG) consistently depicted an area of irritation in accordance with de novo MRI findings. Intraoperative electrocorticogram showed frequent paroxysmal activity in the right frontal lobe; excision of the epileptogenic cortex resulted in a reduction in seizures. CONCLUSION: It is possible that FCD becomes apparent on MRI even after maturation of myelination; thus, repeated MRI is recommended while EEG continues to demonstrate focal findings.
Child s Nervous System 03/2008; 24(2):269-73. · 1.54 Impact Factor
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ABSTRACT: To study the validity of a co-registration method for postimplantation computed tomography (CT) images for localizing the location of an intracranial deep brain stimulator.
Three-dimensional reconstruction images of postimplantation CTs were co-registered with preoperative CTs by stereotactic planning software and used to localize 18 leads in the subthalamic nuclei of 10 patients with Parkinson's disease. Our conventional method using superimposition of sagittal postimplantation magnetic resonance (MR) images were employed as a comparison.
The co-registered CT images separately visualized four individual contacts; on the other hand, the MR superimposition method demonstrated the leads as a group of no MR signal areas. Although laterality of the distal contact did not differ between two methods, the distal contact was located more anteriorly and inferiorly by the MR superimposition method than by the CT co-registration method.
The CT co-registration method is superior to MR in visualizing deep brain stimulation contacts and resolves problems of MR safety in patients treated with a neurostimulator.
Stereotactic and Functional Neurosurgery 02/2008; 86(3):162-6. · 1.85 Impact Factor
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ABSTRACT: In surgery for epileptogenic glioneuronal tumor in the temporal lobe, whether additional hippocampectomy is needed remains in dispute. We retrospectively analysed clinical profile and seizure outcome in a consecutive series of six patients, paying special attention to pathophysiologic conditions in the ipsilateral hippocampus. Long-term video electroencephalography (EEG) monitoring showed attenuation of background activity, followed by ictal discharges in the ipsilateral temporal region in five cases. (18)Fluorodeoxyglucose-positron emission tomography (FDG-PET) in five cases showed hypometabolism in the ipsilateral medial temporal lobe. Intraoperative electrocorticography (ECoG) after removal of the tumor revealed frequent paroxysmal activity or electrographic seizure activity on the hippocampus in five cases. A high incidence of hippocampal pathology, such as hippocampal sclerosis in four cases and dysgenesis in one case, was demonstrated. Five patients who underwent additional hippocampectomy along with resection of the tumor became completely seizure-free. Our findings indicated a proclivity for the epileptogenic zone to encompass the medial structures and for hippocampal pathology to be present even when no direct medial tumor involvement was identified. Thus, it is conceivable that removal of the hippocampus with the guidance of pre- and intraoperative multimodal examinations, in addition to resection of the tumor, may be recommended to achieve 'complete' freedom from seizures.
Neurological Research 01/2008; 29(8):807-15. · 1.52 Impact Factor
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ABSTRACT: The aim of this study was to evaluate three-dimensional Fourier transformation-constructive interference in steady-state (CISS) imaging as a preoperative anatomical evaluation of the relationship between the placode, spinal nerve roots, CSF space, and the myelomeningocele sac in neonates with lumbosacral myeloschisis.
Five consecutive patients with lumbosacral myeloschisis were included in this study. Magnetic resonance (MR) CISS, conventional T1-weighted (T1-W) and T2-weighted (T2-W) images were acquired on the day of birth to compare the anatomical findings with each sequence. We also performed curvilinear reconstruction of the CISS images, which can be reconstructed along the curved spinal cord and neural placode.
Neural placodes were demonstrated in two patients on T1-W images and in three patients on T2-W images. T2-W images revealed a small number of nerve roots in two patients, while no nerve roots were demonstrated on T1-W images. In contrast, CISS images clearly demonstrated neural placodes and spinal nerve roots in four patients. These findings were in accordance with intraoperative findings. Curvilinear CISS images demonstrated the neuroanatomy around the myeloschisis in one slice. The resulting images were degraded by a band artifact that obstructed fine anatomical analysis of the nerve roots in the ventral CSF space. The placode and nerve roots could not be visualized in one patient in whom the CSF space was narrow due to the collapse of the myelomeningocele sac.
MR CISS imaging is superior to T1-W and T2-W imaging for demonstrating the neural placode and nerve roots, although problems remain in terms of artifacts.
Neuroradiology 07/2007; 49(7):579-85. · 2.82 Impact Factor
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ABSTRACT: To investigate the correlation between scalp-recorded electroencephalographic (EEG) and electrocorticographic (ECoG) activities during ictal periods.
Simultaneous EEG and ECoG recordings with chronic subdural electrodes were performed in eight patients with partial epilepsy.
In two cases where the ictal ECoG discharges originated in deep brain structures such as the hippocampus and interhemispheric surface of the frontal lobe, ictal discharges could not be detected on EEG until they expanded to the cortex of convexity. In four cases, the ictal onset zones were located in the lateral convexity. When synchronous or near synchronous ictal ECoG discharges with amplitudes of 200-2000muV were recorded on more than 8-15cm(2) of cortex, corresponding discharges were recorded on EEG in these four cases. However, in a case of frontal lobe epilepsy, asynchronous ictal ECoG discharges were recorded on 10 electrodes of convexity but no ictal EEG activity was recorded. Furthermore, in two frontal lobe epilepsy cases, ictal EEG discharges did not always reflect the ictal ECoG spike, but occasionally reflected slow background ECoG activity around the ictal discharges.
Multiple factors such as the width of the cortical area involved, amplitude of ictal discharges and degree of synchronization of electrical potentials play important roles in the appearance of ictal EEG recordings, and the relationship between ictal EEG and ECoG is not straightforward.
Seizure 05/2007; 16(3):238-47. · 1.80 Impact Factor
