T Hatayama

Hirosaki University, Khirosaki, Aomori Prefecture, Japan

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Publications (36)35.12 Total impact

  • Hana Tobishima, Toru Hatayama, Hiroki Ohkuma
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    ABSTRACT: Mentalis muscle responses to electrical stimulation of the zygomatic branch of the facial nerve are considered abnormal muscle responses (AMRs) and can be used to monitor the success of decompression in microvascular decompression (MVD) surgery. The aim of this study was to compare the long-term outcome of MVD surgery in which the AMR disappeared to the outcome of surgery in which the AMR persisted. From 2005 to 2009, 131 patients with hemifacial spasm received MVD surgery with intraoperative monitoring of AMR. At 1 week postsurgery, spasms had resolved in 82% of cases in the AMR-disappearance group and 46% of cases in the persistent-AMR group, mild spasms were present in 10% of cases in the AMR-disappearance group and 31% of cases in the persistent-AMR group, and moderate were present spasms in 8% of cases in the AMR-disappearance group and 23% of cases in the persistent-AMR group (P < 0.05). At 1 year postsurgery, spasms had resolved in 92% of cases in the AMR-disappearance group and 84% of cases in the persistent-AMR group, mild spasms were present in 6% of cases in the AMR-disappearance group and 8% of cases in the persistent-AMR group, and moderate spasms were present in 3% of cases in the AMR-disappearance group and 8% of the cases in the persistent-AMR group (P = 0.56). These results indicate that the long-term outcome of MVD surgery in which the AMR persisted was no different to that of MVD surgery in which the AMR disappeared.
    Neurologia medico-chirurgica 12/2013; · 0.49 Impact Factor
  • Toru Hatayama, Hiroki Ohkuma
    No shinkei geka. Neurological surgery 04/2010; 38(4):319-26. · 0.13 Impact Factor
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    ABSTRACT: A case of 52-year-old female presented with dysarthria and paresis of right upper extremity 3 years after an operation and chemotherapy for uterine leiomyosarcoma. Magnetic resonance imaging showed an enhanced mass in the left corona radiata. Brain biopsy was carried out and pathological examination of the specimen showed features of a leiomyosarcoma. Uterine leiomyosarcoma is an uncommon tumor and its metastasis to the brain is rare. Only 13 other cases have been published. The patient underwent gamma-knife therapy and obtains good quality of life.
    No shinkei geka. Neurological surgery 05/2006; 34(4):409-13. · 0.13 Impact Factor
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    ABSTRACT: This study reports for the first time the appearance, extent and duration of auditory neuron apoptosis following injury to the central processes. Apoptosis was studied in a rat model that consisted of compression of the auditory nerve in the cerebellopontine angle cistern with intraoperative recordings of auditory nerve compound action potentials to ensure highly reproducible results. Rats were killed between days 0 and 14 after compression, and apoptosis of spiral ganglion cells (SGCs) was evaluated quantitatively and qualitatively. The average number of TUNEL-positive apoptotic SGCs in each cochlear turn increased from days 1 to 5, and then decreased gradually to an undetectable level on day 14 after compression. The average proportion of apoptotic SGCs identified in any cochlear turn on any day was always lower than 10%. These results of our present study should be useful in determining the therapeutic time window for rescuing auditory neurons undergoing apoptosis due to injury during surgery in the cerebellopontine angle.
    International Congress Series. 01/2004;
  • T Sekiya, N Shimamura, S Suzuki, T Hatayama
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    ABSTRACT: We investigated whether methylprednisolone sodium succinate can ameliorate cochlear nerve degeneration following compression injury on the cerebellopontine angle portion of the cochlear nerve, using a quantitative animal experimental model that we have developed recently. In this model, cochlear nerve degeneration after compression could be quantitatively evaluated, while cochlear ischemia induced by the compression carefully maintained below the critical limit that causes irreversible damage to the cochlea. Eleven rats were treated with methylprednisolone during the pre- and post-compression period. Two weeks after compression, the numbers of SGC were compared between the rats that received the compression without and with methylprednisolone treatment. Methylprednisolone treatment improved the survival of SGC following cochlear nerve injury statistically highly significantly in the basal turn where the traumatic stress had been less than in the other cochlear turns in our experimental setting. Although it was not statistically significant, greater survival was also observed in the other cochlear turns. The results of this experimental study indicated that at least a portion of injured cochlear nerve had been potentially treatable, and that methylprednisolone might prevent such cochlear neurons from entering into the vicious process of irreversible damaging process.
    Hearing Research 02/2001; 151(1-2):125-132. · 2.85 Impact Factor
  • T Sekiya, T Hatayama, N Shimamura, S Suzuki
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    ABSTRACT: During surgery for intrinsic midbrain lesions, we intraoperatively recorded evoked compound muscle action potentials (ECMAPs) from the extraocular muscles and evaluated how this type of intraoperative electrophysiological monitoring could minimize postoperative oculomotor nerve palsy (ptosis and/or diplopia). The ECMAPs were recorded through a spring electrode applied to the extraocular muscle (Method 1, seven cases) or a needle electrode inserted into the superior intraorbital space (Method 2, five cases). The surgeon repeated electrical stimulations whenever tissue of unknown origin was encountered intraoperatively, and this information was used to safely guide surgical resection of the tumors. Using these monitoring techniques, the response-free areas were resected and the areas from which ECMAP responses were recorded were avoided. For all 12 patients, ECMAPs were successfully recorded from the extraocular muscles. Ten patients did not exhibit any postoperative deterioration of oculomotor nerve function. Two patients exhibited deterioration of oculomotor nerve function immediately after surgery, which resolved within 1 month. Equally robust ECMAPs could be recorded with Method 2, compared with Method 1. Intraoperative ECMAP recordings from the extraocular muscles precisely indicated the locations of the oculomotor nuclei and/or intramedullary oculomotor tracts. Although Method 2 is a more indirect method for recording ECMAPs than is Method 1, Method 2 was equally useful in recording ECMAPs, which seemed to be the summed potentials from the superior rectus muscle and the levator palpebrae superioris muscle. These monitoring techniques are valuable in guiding surgeons to avoid causing inadvertent harm to the oculomotor nuclei and tracts during midbrain surgery, particularly when the neuroanatomic features are distorted by the presence of tumor.
    Neurosurgery 12/2000; 47(5):1170-6; discussion 1176-7. · 2.53 Impact Factor
  • T Sekiya, N Shimamura, T Hatayama, S Suzuki
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    ABSTRACT: Cochlear neurons are inevitably exposed to traumatic stress during surgical removal of an acoustic neuroma; that event is an important cause of postoperative cochlear neuronal degeneration, with subsequent loss of spiral ganglion cells (SGCs). The object of this study was to investigate whether preoperative pharmacological treatment can enhance the resistance of cochlear neurons to the traumatic stress of surgery. Cochlear neuronal degeneration was induced in 17 rats by controlled compression of the cerebellopontine angle portion of the cochlear nerve. Dizocilpine maleate (MK-801; 10 mg/kg), an N-methyl-D-aspartate (NMDA) antagonist, was administered intraperitoneally to six of the 17 rats 30 minutes before compression occurred. Two weeks after compression, each rat was killed, and the numbers of SGCs in histological preparations of temporal bones were counted. Spiral ganglion cells were more numerous in rats administered dizocilpine maleate (p < 0.03) than in rats that did not receive treatment, indicating that receptor-mediated glutamate neurotoxicity may participate in the pathogenesis of trauma-induced cochlear neuron death and that administration of an NMDA antagonist before surgery may protect the nerve from injury leading to hearing loss.
    Journal of Neurosurgery 08/2000; 93(1):90-8. · 3.15 Impact Factor
  • T Sekiya, N Shimamura, T Hatayama, S Suzuki
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    ABSTRACT: Cochlear neurons need their synaptic contacts with both their peripheral (organ of Corti) and central (cochlear nucleus) targets for survival. We examined the in vivo effectiveness of the neurotrophins (NGF, BDNF and NT-3) on cochlear neuronal survival using our in vivo model, in which the central connection alone was selectively and quantitatively interrupted. The particular neurotrophins evaluated in the present study did not appear to have cochlear nerve rescue potential. However, the experimental model reported here can serve as a useful tool to investigate cochlear neuronal degeneration from the central side, which may lead to identification of effective mediators in the future.
    Acta Oto-Laryngologica 07/2000; 120(4):473-9. · 1.11 Impact Factor
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    ABSTRACT: Although many surgical or endovascular treatments for ruptured vertebral artery dissection have been reported, the best treatment is controversial. We treated five cases of ruptured vertebral artery dissection distal to the origin of the posterior inferior cerebellar artery (PICA), using retrievable platinum coils packed in the dissection site and the immediately proximal vertebral artery. All patients had a contralateral vertebral artery of the same calibre or larger. All dissections were occluded completely, together with the portion of the vertebral artery distal to the PICA origin. No complications related to the procedure were seen. The purpose of the treatment is to isolate the dissection from the cerebral circulation. Occlusion of the rupture site, preserving perforating arteries arising from the vertebral artery, would be ideal. Short-segment occlusion by retrievable platinum coils is close to the ideal.
    Neuroradiology 06/2000; 42(5):384-7. · 2.70 Impact Factor
  • T Sekiya, T Hatayama, N Shimamura, S Suzuki
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    ABSTRACT: Because traditional classifications of vestibular schwannomas (according to relative size) cannot comprehensively describe lesions that grow in different patterns after arising in regions as diverse as the cerebellopontine (CP) angle, the internal auditory canal, and the region lateral to the fundus of the internal auditory canal (labyrinth), we developed a new system to classify vestibular schwannomas, a system that describes the anatomical structures involved by the tumour, rather than size alone. The vestibular schwannoma is classified first by location and then by extent. Our system provides surgeons information helpful in choosing the surgical approach, in estimating the difficulty of tumour excision, and in determining whether hearing might be preserved. Our system also avoids confusion and misunderstanding in discussions of treatment results because it reflects the diverse biological characteristics of vestibular schwannomas.
    Journal of Clinical Neuroscience 04/2000; 7(2):129-33. · 1.25 Impact Factor
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    ABSTRACT: A method for intraoperative electrophysiological mapping of the intracranial root of the trigeminal nerve was studied in five patients with trigeminal neuralgia. During surgery, the trigeminal nerve root was stimulated centrally with a bipolar electrode, and antidromic responses were recorded peripherally from three branches of the trigeminal nerve in the face. In all patients, the fibers of the individual subdivisions of the trigeminal nerve root were successfully localized based on the peripheral sites of antidromic response. This neural mapping was used during microvascular decompression in four patients and during a rhizotomy procedure in one patient. As a result of mapping, the fibers of the trigeminal division subserving the pain were clearly confirmed to be compressed by the artery in all four patients who were undergoing microvascular decompression. Likewise, the antidromic responses precisely identified the first division of the trigeminal nerve, which should be preserved to avoid postoperative corneal ulcers in patients undergoing rhizotomy. Based on these findings, it was concluded that this technique enables surgeons to precisely identify which fibers of the trigeminal nerve root should be decompressed or divided during surgery for trigeminal neuralgia.
    No shinkei geka. Neurological surgery 03/2000; 28(2):127-34. · 0.13 Impact Factor
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    ABSTRACT: In the available in vivo experimental models for cochlear neuronal degeneration, the peripheral (hair cell side) process of the cochlear nerve has been injured in order to induce neuronal degeneration. However, there has been no dependable experimental model in which cochlear neuronal degeneration begins from the central (brain stem side) process. This lack of a central process injury model has probably been due to the experimental difficulties that had to be overcome in order to reproducibly and selectively injure the central process of the cochlear neurons while maintaining the patency of the internal auditory artery in small experimental animals such as rats. Using rats, we first developed a central process injury model in which the reduction of the spiral ganglion cells due to retrograde degeneration of cochlear neurons can be quantitatively evaluated. In our experimental model, the cochlear nerve was compressed and injured by a compression-recording (CR) electrode placed at the internal auditory meatus. First, the cochlear nerve was compressed until the compound action potentials of the cochlear nerve became flat, and then the CR electrode was advanced by various compression speeds (5, 10, or 200 micrometer/s) to reach the same depth (400 micrometer). In our model, therefore, the reduction of the spiral ganglion cells was caused compression speed dependently. This method made it possible to produce compression injury to the cochlear nerve without evidence of damage to the blood supply to the cochlea via the internal auditory artery. This model gives us the means to obtain knowledge that was previously impossible to derive from the peripheral process injury models.
    Experimental Neurology 03/2000; 161(2):490-502. · 4.65 Impact Factor
  • T Hatayama, T Sekiya, S Suzuki, T Iwabuchi
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    ABSTRACT: The short- and long-term effects of static compression of the cochlear nerve were studied in dogs. The nerve was exposed in the cerebellopontine angle and a modified aneurysm clip was applied to reduce the diameter of the nerve trunk to 50%, 40%, 30% or 20% of normal (designated respectively as 50%, 60%, 70%, and 80% compression). Brainstem auditory evoked potentials (BAEPs) were monitored intraoperatively and post-operatively. The animals were sacrificed between 5 and 119 days after nerve compression and temporal bones were examined histologically. In the 50% compression group, all peaks except peak I disappeared immediately after nerve compression. After release of the clip, however, peak II and subsequent components recovered and prolonged interpeak latency (IPL) between peaks I and IV normalized within 7 days. In the 60% compression group, recovery was incomplete for as long as 49 days after compression. Significant histological changes were not always reflected in the electrophysiological recordings, as shown by the finding of multiple cavitations at the compressed portion of the cochlear nerve in cases in which conduction block of cochlear nerve impulses was reversible. In the 70% compression group, peak IV did not reappear for more than 1 week, and histological examination revealed severe damage to all cochlear nerve fibers except those from the apical turn, which lie in the center of the cochlear nerve trunk. Severe injury occurred to the cochlear nerve fibers that are situated more superficially in the nerve, which are tonotopically responsible for the perception of high-frequency sound and the generation of BAEPs. This means that the BAEP changes due to cochlear nerve compression would be detectable by BAEP monitoring, although changes in the apical region of the cochlea are not fully detectable by BAEP monitoring. In the 80% compression group, all peaks except peak I were lost permanently and the amplitude of peak I, which had been preserved in the acute phase, gradually decreased. Reversibility of impaired cochlear nerve impulse conduction was related to the severity of compression, and at some level of compression between 70% and 80% the nerve fibers generating BAEPs permanently lost the ability to conduct electrical impulses proximal to the site of compression. In the 70% and 80% compression groups, the amplitude of peak I gradually decreased over the first 30 days after compression and did not change significantly thereafter. Histologically, the branches of the internal auditory artery were resilient to compression, although they are easily avulsed due to stretch force. Furthermore, retrograde degeneration of cochlear neurons triggered by compression at the cisternal portion of the cochlear nerve was apparent. Such slowly progressive degeneration of nerve fibers may play a part in development of the delayed postoperative hearing disturbance.
    Neurological Research 10/1999; 21(6):599-610. · 1.18 Impact Factor
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    ABSTRACT: Adequate electrophysiological techniques to monitor function of the cauda equina have been proposed for surgery in patients with lumbosacral lipoma or myeloschisis. Motor fibers were identified by electrical stimulation in the operating field with bipolar rectangular impulses of 200 mu sec duration at 2 Hz under 5 mA and compound muscle action potentials (CMAPs) recorded from the leg and anal muscles. By recording CMAPs from the tibialis anterior, the biceps femoris, the gastrocnemius, and the external anal sphincter muscles, all of the roots from the fourth lumbar to the fourth sacral segment were continuously monitored. To spare recording channels, recordings were obtained from the right versus the left side. In our institute, 5 patients have undergone lumbosacral surgery while using this monitoring system, and the results indicated that there was no postoperative neurological exacerbation in any of the cases. According to a combination of the CMAPs produced by stimulation, the segment of the stimulated motor root could be identified electrophysiologically. Monitoring of somatosensory evoked potentials was not performed because this would have required too much time and would have prolonged surgery. However, some sensory fibers, which appeared to be posterior roots of the cauda equina on intraoperative inspection, could be identified indirectly with CMAPs recording because of current spreading from the stimulation to motor fibers.
    No shinkei geka. Neurological surgery 05/1999; 27(4):317-22. · 0.13 Impact Factor
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    ABSTRACT: A 72-year-old man developed left facial palsy at age 14 and left-sided hearing loss at age 20. At the age of 59, he presented with gait disturbance, and a large left cerebellopontine angle tumor was detected, which had markedly destroyed the pyramidal bone. The tumor was subtotally resected, but he required two more operations at the ages of 64 and 69 because of tumor regrowth. At the present time, recurrent tumor has destroyed the occipital bone and is invading the scalp. However, even though he has several cranial nerve palsies and cerebellar ataxia, he remains in stable condition and demonstrates long-term survival. The patient's surgical specimens revealed a papillary adenoma, which was recently thought to be of endolymphatic sac origin, although the origin of this kind of tumor, whether arising from the middle ear or from the endolymphatic sac, has not been established with certainty so far. In this paper, we provide further evidence that this tumor originates from the endolymphatic sac, based on anatomical, histopathological, and embryological evidence.
    Brain Tumor Pathology 02/1999; 16(2):69-76. · 1.58 Impact Factor
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    ABSTRACT: A case of unclippable partially thrombosed giant basilar artery (BA) aneurysm was treated successfully by intra-aneurysmal GDC embolization followed by proximal BA occlusion. Balloon occlusion test of the BA showed a good opacification of the aneurysm angiographically through plentiful collateral flow from anterior circulation. This combination may prevent coil compaction and will promote intra-aneurysmal thrombosis.
    Interventional Neuroradiology 11/1998; 4 Suppl 1:85-8. · 0.77 Impact Factor
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    ABSTRACT: The authors describe the histopathological findings in a case involving rerupture of a recanalized aneurysm of the internal carotid artery 8 months after partial (95%) embolization with interlocking detachable coils. The aneurysm was filled with poorly organized thrombus, and its orifice was devoid of endothelial cells. It appears likely that a long period of observation may be required to confirm the complete thrombotic organization of coil-embolized aneurysms. This indicates that caution is needed because rupture may follow recanalization of the aneurysm.
    Journal of Neurosurgery 07/1998; 88(6):1096-8. · 3.15 Impact Factor
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    ABSTRACT: We report a simple and easily-applicable method to intraoperatively monitor the oculomotor nerve and oculomotor nucleus in the brainstem. A needle electrode is inserted into the space just beneath the superior root of the orbit. With this superior orbital electrode, evoked compound muscle action potentials from the superior rectus and the levator palpebrae superioris muscles were recorded. The nuclei for these two muscles are located caudally in the midline of the midbrain. The responses from the superior orbital electrode, therefore, give the surgeons useful intraoperative guidance during surgery for pineal region tumors and midbrain gliomas.
    No shinkei geka. Neurological surgery 12/1997; 25(11):987-92. · 0.13 Impact Factor
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    ABSTRACT: Twelve cases of ruptured cerebral aneurysm were treated in acute stage with interlocking detachable coils (IDC, Target Therapeutics, Fremont, California) and the outcome was assessed. IDCs were placed intra-aneurysm for intraaneurysmal occlusion, or intra-artery for proximal occlusion. Cases: age 36-84 (mean; 60) y.o., 11 females and 1 male; 1, 5, 4 and 2 patients were categorised (Hunt and Hess) as grades 1, 2, 3 and 4 respectively. An intra-aneurysmal occlusion in ten cases and a proximal occlusion in two were performed on day 1-11 (mean 4). On angiograms and CT findings, the ruptured point seemed to have occluded in all cases. The occlusion rate was 100% in five cases, 95% in two, 90% in three, 80% in one, and less than 50% in one. There were two cases of technical complication, one a coil migration and the other an aneurysmal perforation with IDC. Their Glasgow Outcome Scale six months after embolisation was graded as good recovery in four cases, moderately disabled state in two, severely disabled state in one, and dead in five. Follow-up angiograms taken four to six months after embolisation showed an intra-aneurysmal coil compaction in five cases. Two of these were treated by a second embolisation or by neck clipping followed by aneurysmal resection, but another two were observed without any treatment and the last one died of rebleeding. Histological examination of the resected embolised aneurysm revealed slight organization around coils but no endothelialisation over the aneurysmal orifice. In our experience, coil embolisation with IDC for acute ruptured aneurysm is a promising means of preventing rerupture during subacute stage.
    Interventional Neuroradiology 03/1997; 3(1):49-63. · 0.77 Impact Factor
  • Clinical Neurology and Neurosurgery - CLIN NEUROL NEUROSURG. 01/1997; 99.