[Show abstract][Hide abstract] ABSTRACT: Introduction :Vagal nerve stimulation(VNS)is a less invasive palliative treatment for intractable epilepsy and was approved for use in Japan in July 2010. Surgical complications of VNS such as vagal nerve dysfunction, cardiac arrhythmia with asystole, and vocal cord palsy as well as complications arising from fracture of the leads or generator and infections are well known in the West. The aim of the present report is to describe the surgical complications encountered in our hospital and discuss their countermeasures. Material and Methods: We reviewed the clinical records of 26 patients who underwent VNS therapy between March 2011 and June 2013. The cases involved 17 male and 9 female patients, including 8 children(<15 years of age). Results :Three patients(11.5%)experienced severe bradycardia and cardiac asystole following test stimulations of the vagal nerve with a stainless-steel surgical hook left in place, to extend the operative field. It was believed that the current spread through the hook and stimulated the cardiac branch of the vagal nerve. In an adult patient with severe intellectual disability, inappropriate dermatological therapy for a superficial purulent wound on the neck caused lead infection 10 months postoperatively. In a child with moderate intellectual disability, lead fracture was noted in association with rotation of the pulse generator at one month postoperatively. In the former case, the lead was cut off whilst the electrode and anchoring coil on the vagal nerve remained;the whole VNS system was removed in the latter case. Subfascial implantation of the generator was recommended. In an adult patient, disconnection between the leads and generator head was noted at 10 months postoperatively. Conclusions :During intraoperative test stimulations of the vagal nerve, stainless-steel surgical hooks should be removed to avoid the spread of current. In intellectually disabled patients, the pulse generator should be placed in the subfascial area instead of the subcutaneous area, especially children. The connection between the leads and the generator should be performed with the aid of a microscope, after removal of the fluid and tissue.
No shinkei geka. Neurological surgery 05/2014; 42(5):419-428. · 0.13 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: PURPOSE: The aim of this study was to evaluate the usefulness of three-dimensional T1-weighted spoiled gradient-recalled echo (3D T1-GRE) images for the preoperative anatomical evaluation of lumbosacral lipoma, thick filum terminale, and myelomeningocele as a means of compensating for the drawbacks of 3D heavily T2-weighted (3D hT2-W) images. METHODS: Nine patients with lumbosacral lipomas, one patient with tight filum terminale, and five patients with myelomeningoceles were included in this study. 3D T1-GRE images were compared with 3D hT2-W images or conventional magnetic resonance images in terms of delineation of lipomas and other structures in the patients with lipomas and tight filum terminale. For patients with myelomeningoceles, 3D T1-GRE images were compared with 3D hT2-W images in terms of artifacts in the cerebrospinal fluid (CSF) space. RESULTS: The 3D T1-GRE images demonstrated lipomas with good contrast to the spinal cord and CSF space and more clearly delineated the anatomical relationship between lipomas and these structures than did the 3D hT2-W images. The 3D T1-GRE images delineated dural defects through which extradural lipomas penetrated into the intradural space. The 3D T1-GRE images also demonstrated the presence or absence of lipomas in the filum terminale and the absence of artifact in the myelomeningoceles. Furthermore, they were useful for differentiating artifacts observed on the 3D hT2-W images from nerve elements. CONCLUSIONS: The complementary use of 3D T1-GRE and 3D hT2-W images may compensate for the drawbacks of 3D hT2-W images and may eventually improve lesion visualization and surgical decision making.
Child s Nervous System 05/2013; · 1.24 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The analysis of epileptic discharges in magnetoencephalography with minimum norm estimates (MNE) is expected to provide more precise localization of epileptic discharges compared with electroencephalographic estimations. However, the clinical feasibility of MNE remains unclear. In this study, we aimed to elucidate the onset and propagation patterns of interictal spikes using MNE. Seven patients with intractable epilepsy whose epileptogenicity was assumed to exist in the convexity of the cerebral cortex were studied. For MNE and electrocorticography (ECoG), we characterized the propagation patterns of interictal epileptic discharges according to the area in which they originated and where they extended; we then examined whether the propagation patterns observed in MNE were identified by ECoG. We also examined the relationship between the positions of spikes estimated by the equivalent current dipole (ECD) method and MNE. Among the seven patients, nine propagation patterns of epileptic discharges were observed by MNE, all of which were also identified by ECoG. In seven patterns, the epileptic activity propagated around the initial portion. However, in two patterns, the center of activities moved according to propagation with maintained activity of the initial portion. The locations of spikes identified by the ECD method were within the areas estimated by MNE when the epileptic activity propagated. However, the ECD method failed to detect onset activities identified by MNE in three of nine patterns. Thus, MNE is more useful as a means of presurgical evaluation for epilepsy than the ECD method because it can delineate the onset of epileptic activities as shown in ECoG.
[Show abstract][Hide abstract] ABSTRACT: In patients with epilepsy associated with Sturge-Weber syndrome (SWS), epileptogenesis has been suggested to be caused by chronic ischemia in cortical areas affected by leptomeningeal angiomatosis or by ischemia-related cortical malformations. However, this has not been fully verified electrophysiologically. We herein present two cases of SWS with medically intractable epilepsy in which the epileptogenic area involved focal cortical dysplasia (FCD) type IIa near the region of leptomeningeal angiomatosis. In both cases, the ictal-onset zones were identified by chronic subdural electrodes, and the presence of FCD type IIa was shown histopathologically. In SWS, especially in association with focal leptomeningeal angiomatosis, FCD may thus play a major role in epileptogenesis. FCD should therefore be demonstrated by the collective findings of perioperative neurophysiologic examination, anatomic and functional neuroimaging, and histopathologic examination.
[Show abstract][Hide abstract] ABSTRACT: Vagus nerve stimulation (VNS) is a palliative treatment for medically intractable epilepsy and has been covered by public health insurance in Japan since July 1, 2010. The frequency of the use of VNS during the first year of insurance coverage was determined by assessing the number of cases for which VNS was performed in Kyushu Rosai Hospital, the number of registered cases, and the questionnaire survey filled by 68 surgeons who are board certified as both epileptologists and neurosurgeons. VNS devices were placed in 98 patients from July 2010 to June 2011. These devices were placed in an average of 4.4 patients per month from July 2010 to November 2010 and in an average of 10.9 patients from December 2010 to June 2011. However, we did not observe an increasing trend. Almost all of the surgeries were performed in the Kanto (56 patients in 8 institutes) and Tokai (24 patients in 2 institutes) areas. VNS was not performed in many institutes primarily because VNS was not indicated for any of the patients. The questionnaire survey indicated that the use of VNS was likely to increase with an increase in the number of neurologists who decide on performing VNS preoperatively and regulate the conditions of the vagus nerve stimulator postoperatively. In conclusion, VNS is currently being applied in a limited number of institutes in the Kanto and Tokai areas, and a close association between the epileptologists and neurologists during preoperative and postoperative periods will increase the use of VNS.
Brain and nerve = Shinkei kenkyū no shinpo 06/2012; 64(6):681-7.
[Show abstract][Hide abstract] 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.
[Show abstract][Hide abstract] ABSTRACT: Objective: The feasibility of peri-orbital electrodes, which are not invasive and do not induce pain, as a supplemental electrode for detection of ictal discharges in medial temporal lobe epilepsy (MTLE) was examined. Methods: Patients with MTLE, who underwent video-EEG monitoring with simultaneous peri-orbital and sphenoidal electrodes and obtained good outcome following standard anterior temporal lobectomy, were subjects in this study. Initial ictal discharge amplitudes were compared between sphenoidal (Sp1/ 2), standard anterior temporal in 10-20 system (F7/ 8), peri-orbital (superior orbital lateral: SOL, inferior orbital medial: IOM), frontopolar (Fp1/ 2), frontal (F3/4) and ear (A1/ 2) electrodes. Results: A total of 34 consecutive seizures from 20 patients were analyzed, with a maximum amplitude observed at Sp1/2 (57.57±5.59), followed by F7/8 (54.89±5.59), SOL (50.97±5.59), IOM (46.95±5.59), A1/2 (45.07±5.69), Fp1/2 (44.78±5.62), and F3/4 (37.75±5.66) (mean±standard error, μV). There was no statistical difference between Sp1/2, F7/8, SOL, and IOM values. When the sphenoidal electrode was omitted, 13 seizures (13/34, 38.2%) resulted in the highest amplitude at peri-orbital electrodes and 10 seizures (10/ 34, 29.4%) at F7/8. Conclusions: Peri-orbital electrodes could detect ictal discharges in MTLE as well as sphenoidal and standard anterior temporal electrodes in 10-20 system and are useful for supplemental recording for detecting ictal epileptiform discharges in MTLE.
Neurology Asia 01/2011; 16(4):303-307. · 0.15 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Based on the data reported in the National Institute of Science and Technology Policy 2010, Japan is ranked in fourth place in the world in terms of the numbers of the articles in the fields of clinical medicine. However, there had not been any objective data regarding the numbers of publications by neurosurgeons. As it is important for neurosurgeons to realize the extent of academic contributions by the neurosurgeons in different countries, the numbers of publications in the major journals by the members of the Japan Neurosurgical Society and those from neurosurgical institutions around the world were analyzed using both the biomedical literature database PubMed and the publication database "ISI Web of Knowledge." Parts of the results were presented in the 69th Annual Meeting of the Japan Neurosurgical Society. As to the number of neurosurgical publications in English from the top 9 countries, the US has been consistently in first place and Japan in second. However, the number of publications from Japan has been decreasing since 2000. With regards to the "top 8 journals" such as the Lancet and the Journal of the American Medical Association, the number of first-author publications by Japanese neurosurgeons increased in the late 1980s and had been 2-9 articles per year until recently. In the "top 12 neuroscience journals" which include Stroke, Neuro-Oncology, Cancer Research, and others, Japan had been in the third next to the US and UK till 2004, but Germany surpassed Japan in 2005. In the "top 6 clinical journals" such as the Journal of Neurosurgery and Neurosurgery, the US has been consistently keeping first place and Japan second place since 1977. Searches using the key word elucidated that Japanese neurosurgeons are greatly contributing in the field of "aneurysm." Regarding the number of publications per neurosurgeon, Canada and UK are in the forefront and Japan is down to eighth place. Japanese neurosurgeons have been contributing greatly next to the Americans to the field of clinical neurosurgery and neuroscience by publishing in English. However, the number of publications by Japanese neurosurgeons has been declining since 2000. The Japan Neurosurgical Society must come up with countermeasures to address this problem.
[Show abstract][Hide abstract] ABSTRACT: We report a rare case of focal cortical dysplasia (FCD) concurring with diffuse astrocytoma and arachnoid cyst, and also re-evaluate the glial component in archival FCD cases for the differential diagnosis of diffuse gliomas. A 7-year-old boy with a 9-month history of psychomotor seizures disclosed a hyperintense area accompanied by a cystic lesion in the left temporal lobe on MRI. The surgical specimen displayed dyslamination of the cortices and ectopic neurons in the white matter, associated with dysmorphic neurons, indicating FCD type IIA. Additionally, the lesion showed diffuse proliferation and infiltration of glial cells, immunopositive for infiltrating glioma markers (nestin, doublecortin, MAP-2e) and p53, and MIB-1 index was 2.0%. These findings indicated coexisting diffuse astrocytoma. Coexistence of diffuse glioma with FCD is unusual, but we often notice increased population of small glial cells in FCD lesions. Re-evaluation of archival FCD cases with diverse markers revealed that reactive microglia significantly proliferate in the white matter lesions. Therefore, a careful pathological assessment has to be made to define a rare case of diffuse glioma occurring in FCD.
[Show abstract][Hide abstract] ABSTRACT: To examine the utility of fluid-attenuated inversion recovery (FLAIR) imaging and three-dimensional short tau inversion recovery (3DSTIR) imaging using a 3-Tesla (3-T) magnetic resonance (MR) imager in the preoperative evaluation of hippocampal sclerosis (HS).
Thirteen patients with intractable medial temporal lobe epilepsy who underwent anterior temporal lobectomy with amygdalohippocampectomy were studied. MR images were obtained twice, once with a 1.5-T imager and once with a 3-T imager. The extent of hippocampal resection was determined according to the findings on intraoperative hippocampal electroencephalography. We compared the diagnostic utility of FLAIR for HS between 1.5-T and 3-T MR imaging. In addition, the relationship between the existence of hypointense areas in the hippocampus (HIAs) on 3DSTIR and the severity of HS pathology (as evaluated using Watson's grading) was examined. The relationship between postoperative seizure outcome and postoperatively remaining HIAs was also evaluated.
There was no difference between FLAIR images from 1.5-T and 3-T imaging in the detection of HS. With 3DSTIR, an HIA in unilateral hippocampus was observed in all of the nine cases exhibiting severe pathologic HS (Watson's grade III-V). In seven cases with HIA, the extent of hippocampal resection was smaller than the HIAs. Every case showed good seizure outcome (Engel's class I and II).
In the diagnosis of HS, no substantial difference was noted between 1.5-T and 3-T MR imaging. However, 3DSTIR using 3-T MR imaging is useful for evaluating the extent of HS, although postoperative HS remnants are not correlated with surgical outcomes.
[Show abstract][Hide abstract] ABSTRACT: The aims of this study are (1) to assess the effects of volatile anesthetics on regional cerebral blood flow (rCBF) and electrocorticography (ECoG), and (2) to investigate the relationship between rCBF and ECoG influenced by volatile anesthetics. The authors measured rCBF using laser Doppler flowmetry and ECoG simultaneously and continuously from the same cortex during craniotomy, using the specially arranged probe. Patients received intravenous anesthetics with nitrous oxide until craniotomy, and after opening of dura, volatile anesthetic, either isoflurane or sevoflurane, was started and was gradually increased for the measurement. Four of the nine cases (44.4%) of the sevoflurane group showed no change both in rCBF and ECoG. In three cases (33.3%), rCBF increased as the frequency of the paroxysmal activities increased. In two cases (22.2%), decreased rCBF was accompanied by slow waves. In 12 cases of the isoflurane group, no apparent rCBF and ECoG changes were seen, except a case with decreased rCBF and slow waves. This is the first report of simultaneous recordings of regional CBF and neuronal activity under general anesthesia. During sevoflurane and isoflurane anesthesia <2.5 minimum alveolar anesthetic concentration, rCBF is affected by ECoG activities rather than pharmacologic action of inhalational anesthetics.
Journal of clinical neurophysiology: official publication of the American Electroencephalographic Society 04/2010; 27(2):110-5. · 1.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Myeloschisis is the most serious and complex congenital anomaly in spina bifida manifesta (cystica). However, with improvements in medical care and increased understanding of its pathophysiology, the associated long-term morbidity and mortality rates have been significantly reduced. This article reviews various issues associated with the neurosurgical management of patients with myeloschisis, such as perinatal management, repair surgery for myeloschisis, neurosurgical management of hydrocephalus, Chiari malformation type II, tethered cord syndrome and epilepsy, and intrauterine fetal surgery.
[Show abstract][Hide abstract] 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.
[Show abstract][Hide abstract] 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
[Show abstract][Hide abstract] 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. · 1.46 Impact Factor
[Show abstract][Hide abstract] 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. · 3.15 Impact Factor
[Show abstract][Hide abstract] 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. · 1.46 Impact Factor
[Show abstract][Hide abstract] 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.