Sekiya Tetsuji

Sekiya Tetsuji
Kyoto University Graduate School of Medicine · Otolaryngology, Head and Neck Surgery

MD.

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94
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Publications

Publications (94)
Article
Full-text available
Cell transplantation therapy has long been investigated as a therapeutic intervention for neurodegenerative disorders, including spinal cord injury, Parkinson's disease, and amyotrophic lateral sclerosis. Indeed, patients have high hopes for a cell-based therapy. However, there are numerous practical challenges for clinical translation. One major p...
Chapter
Cell transplantation is regarded as one of the potential therapies to replace diseased auditory neurons and experimental studies have been compiled to revive auditory neurons during the last decade. Revitalizing auditory neurons are crucial to accomplish rewiring of peripheral auditory system in toto as they are essential for the survival and maint...
Article
Auditory nerve is a bundle of bipolar auditory neurons forming synapses peripherally with hair cells and centrally with cochlear nucleus cells. Spiral ganglion cells are the cell bodies of auditory neurons. The auditory neurons commonly degenerate both when hair cells are damaged initially and when axons of auditory nerve are injured primarily. Aud...
Article
The effect of acoustic overstimulation on the neuronal number of the cochlear nucleus (CN) was investigated by using unbiased stereological methods in rats. We found that, after 9 weeks of recovery, neurons in the anteroventral cochlear nucleus (AVCN) degenerated, whereas those in the posteroventral and dorsal cochlear nuclei (PVCN and DCN) were pr...
Article
Hearing levels following microsurgical treatment gradually deteriorate in a number of patients treated for vestibular schwannoma (VS), especially in the subacute postoperative stage. The cause of this late-onset deterioration of hearing is not completely understood. The aim of this study was to investigate the possibility that reactive gliosis is a...
Article
It is well established that the cochlear nucleus (CN) of developing species is susceptible to loss of synaptic connections from the auditory periphery. Less information is known about how de-afferentation affects the adult auditory system. We investigated the effects of de-afferentation to the adult CN by mechanical compression. This experimental m...
Article
Several animal models of auditory neuropathy (AN) have been produced by employing pharmacological agents to damage auditory neurons or hair cells selectively. The specificity of pharmacological lesions is generally assessed by observation of visible structural damage but it is difficult to localize the delivery, which could lead to functional side...
Article
The auditory nerve is an important target in hearing restoration research along with the hair cells. Although there are several potentially useful therapeutic options to rebuild lost hearing, cell transplantation is a very realistic option. Cells can be infused into the auditory nerve without compromising the auditory brainstem responses and damagi...
Article
Cell transplantation is a realistic potential therapy for replacement of auditory sensory neurons and could benefit patients with cochlear implants or acoustic neuropathies. The procedure involves many experimental variables, including the nature and conditioning of donor cells, surgical technique and degree of degeneration in the host tissue. It i...
Article
The peripheral auditory nervous system (cochlea and auditory nerve) has a complex anatomy, and it has traditionally been thought that once the sensorineural structures are damaged, restoration of hearing is impossible. In the past decade, however, the potential to restore lost hearing has been intensively investigated using molecular and cell biolo...
Article
We report a rare case of cerebellopontine angle (CPA) meningioma whose sole symptom was severe vertigo. A 39-year-old woman with right CPA meningioma was referred for surgery. She experienced severe vertigo for 2 years without any other symptoms. Caloric test indicated right canal paresis of 90%. Her audiogram was normal. After surgery, vertigo sym...
Article
We have developed a technique to deliver cells to the inner ear without injuring the membranes that seal the endolymphatic and perilymphatic chambers. The integrity of these membranes is essential for normal hearing, and the technique should significantly reduce surgical trauma during cell transplantation. Embryonic stem cells transplanted at the i...
Article
Because hearing disturbance due to auditory nerve dysfunction imposes a formidable burden on human beings, intense efforts have been expended in experimental and clinical studies to discover ways to restore normal hearing. However, the great majority of these investigations have focused on the peripheral process side of bipolar auditory neurons, an...
Article
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 t...
Article
Although apoptotic changes in auditory neurons induced by injury to peripheral processes (dendrites) have been intensively studied, apoptotic changes in auditory neurons induced by injury to central processes (axons of spiral ganglion cells, SGCs) have not been reported previously, probably due to lack of an experimental model. The present study re...
Article
Trauma-induced hearing loss after cerebellopontine angle manipulation has been regarded as having a hopeless natural course once it occurs. To challenge such a pessimistic view, we investigated whether pharmacological interventions with basic fibroblast growth factor (bFGF) could ameliorate trauma-induced cochlear nerve degeneration. The cerebellop...
Article
Excessive entry of Ca2+ into injured cochlear neurons activates various Ca(2+)-activated enzymes and subsequent spiral ganglion cell death. Therefore, preventing intracellular calcium overload by using Ca2+ channel antagonists may become an important countermeasure to spiral ganglion cell death. We experimentally investigated whether an L-type Ca2+...
Article
Intraoperative monitoring of brainstem auditory evoked potentials (BAEP) has been widely utilized to reduce the incidence of postoperative hearing disturbance due to cerebellopontine angle manipulations. The prolongation of wave V of BAEP is usually used as a criterion to warn the surgeons to modify their surgical maneuvers. However, it is not know...
Article
It has been empirically recognized that the cochlear nerve is highly vulnerable to traumatic stress resulting from surgical procedures; therefore, careful manipulation of the cochlear nerve is mandatory in preventing trauma-induced hearing loss during cerebellopontine angle (CPA) surgery. There is, however, no precise knowledge about the temporal p...
Article
A 20-year-old female experienced temporary unintentional mirror writing associated with low perfusion of the bilateral anterior cerebral arteries. When she was 17 years old, she had developed multiple idiopathic intracerebral hemorrhages and right hemiparesis. At the age of 20, she had a generalized convulsion for which she was transferred to our d...
Article
Post-traumatic invasion of macrophages into the cochlear nerve of the rat and measurement of how their invasion was modified by the administration of methylprednisolone were investigated for the first time by using a reproducible and quantifiable experimental model of cochlear nerve injury. Two weeks after precise cochlear nerve compression, a mass...
Article
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 quantit...
Article
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 spri...
Article
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...
Article
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...
Article
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 de...
Article
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....
Article
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...
Article
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 auditor...
Article
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 pote...
Article
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...
Article
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 p...
Article
We report a case of gliosarcoma with numerous giant cells resembling ganglion cells and having clear nucleoli. A 75-year woman was admitted to our hospital suffering from progressive left hemiparesis and ambulatory disturbance of one week's duration. CT and MRI studies showed ring enhancement on a clear margin mass in the right parieto-occipital lo...
Article
Although monitoring of brainstem auditory evoked potentials (BAEP) is helpful to preserve hearing during operations in the cerebellopontine angle such as microvascular decompression and excision of an acoustic neurinoma, criteria for what and when changes in BAEP should be communicated to the surgeon have not been well established. An exhaustive re...
Article
Acoustic neurinomas containing cystic parts are fairly common, but it is extremely rare for acoustic neurinomas to be mainly composed of cysts. So far, we have encountered three such cases. We studied these cases retrospectively to correlate their characteristic clinical symptoms and their respective pathological findings. Referring to reviews of t...
Article
This paper reports two cases of craniopharyngioma in the elderly (over 70 years old). The first case is a 74-year-old woman who was referred to us due to gait and visual disturbance. She was first treated conservatively because she showed signs of dementia, but her tumor grew remarkably and rapidly after placement of a ventriculoperitoneal shunt an...
Article
Plasma cell granuloma occurs most frequently in the lung and upper respiratory tract; fewer than ten cases have been reported to occur in the central nervous system. A case of intracranial plasma cell granuloma in a 69-year-old male was reported. He visited our clinic, complaining of progressive visual disturbance. The CT in this patient showed a s...
Article
Functional preservation of the lower cranial nerves is an important issue in the surgery of the skull base to avoid postoperative serious complications such as aspiration pneumonia and respiratory disorders. We presented our experience of intraoperative monitoring of the lower cranial nerves during skull base surgery. The evoked electromyographic (...
Article
A flexible aneurysm clip applier with a small spindle-shaped head was manufactured. It is useful for aneurysmal clipping through a narrow space and the clip can be set in various directions due to its flexibility.
Article
Full-text available
We report a case of an acoustic neurinoma that recurred more than 11 years after "total" tumor removal through the posterior cranial fossa. Recurrent tumor had obliterated the petrous bone, filled the middle ear, and was visible grossly at the external auditory meatus. The unique behavior of this tumor implied that the site of origin was within the...
Article
Four cases of pineal cyst were presented and their features on magnetic resonance (MR) imaging were discussed while reviewing the literature relevant to this clinical entity. Pineal cyst is a normal developmental variant and in most of the cases its diagnosis is not difficult, but in a limited number of cases, pineal cyst needs to be differentiated...
Article
A 42-year-old woman suddenly developed headache and nausea on July 26, 1991, and the computed tomography (CT) scan showed a moderate-sized hematoma in the left occipital lobe. After one month's conservative treatment, she had recovered to a neurologically intact state. Cerebral angiography demonstrated a giant arteriovenous malformation fed by enla...
Article
We developed a Micro-neurostimulator that is suitable for intracranial electrical stimulation of the facial nerve in excision of acoustic neurinomas. The tips of our Micro-neurostimulator were thinner and finer than those of commercially-available bipolar forceps and therefore it was possible to stimulate tumor tissue and the facial nerve selective...
Article
During 22 operations in 18 patients, we stimulated the ocular motor nerves electrically, intracranially, and recorded compound muscle action potentials (CMAP) directly from the extraocular muscles with a ring electrode that we developed. Recording electrodes were applied in 52 instances to the superior rectus, medial rectus, superior oblique, or la...
Article
Clinical feasibility and usefulness of various intraoperative electrophysiological monitoring methods that are widely utilized during neurosurgical operations were critically evaluated. We divided these intraoperative monitoring methods (IOM) into two types; the monitoring methods that enable the surgeons to obtain topographical orientation during...
Article
The dura mater adjacent to the attachment of meningiomas was enhanced on MR imaging with intravenous Gd-DTPA infusion. It was examined histologically in four patients with intracranial globoid meningiomas. Histological examination revealed that there was no tumor cell invasion within the dura mater enhanced on MR imaging, except at the point of the...
Article
Electrical stimulation was applied on the surface of the eighth cranial nerve in the cerebellopontine angle of dogs and the evoked potentials were recorded with surface electrodes on the scalp. The shape of the evoked potentials recorded was different according to the portion of the nerve stimulated electrically. It was, therefore, possible to prec...
Article
We encountered five cases of intracranial lipoma after introduction of MRI. They were located in the quadrigeminal plate, interpeduncular fossa, pineal region and two of them were found in the cerebellopontine angle, (although intracranial lipoma in this location has been reported to be extremely rare). MRI can precisely locate a small lesion that...
Article
A ring-shaped electrode was developed and used in 20 patients to record evoked electromyographic responses directly from the extraocular muscles during skull base surgery. Intra-operative monitoring with this electrode helps the surgeon to localize the nerves that innervate the extraocular muscles precisely and to refrain from disturbing important...
Article
We report a case of hemifacial spasm in which hearing was well preserved after microvascular decompression, but the vestibular nerve was injured selectively. We review the pathophysiological mechanisms relevant to this complication in the light of results of animal experimental studies we have conducted. In addition, we discuss the clinical signifi...
Article
Changes of plasma thromboxane level in subarachnoid haemorrhage (SAH) were studied clinically and experimentally using 11-dehydro-thromboxane B2 (11 DTX) as a measuring index. 11 DTX is a major long-lived metabolite formed from thromboxane (TX) B2, and is said to be a more reliable parameter for detecting TXA2 production in biological systems. In t...
Article
: The authors report the case of a 17-year-old girl who underwent excision of bilateral neurinomas of the cerebellopontine angle. Although her auditory evoked potentials were well maintained during the operation, they deteriorated gradually and progressively for the following 2 months. This seemed to reflect degeneration of the cochlear nerve fiber...
Article
The authors report the case of a 17-year-old girl who underwent excision of bilateral neurinomas of the cerebellopontine angle. Although her auditory evoked potentials were well maintained during the operation, they deteriorated gradually and progressively for the following 2 months. This seemed to reflect degeneration of the cochlear nerve fibers...
Article
Changes of plasma thromboxane level in subarachnoid haemorrhage (SAH) were studied clinically and experimentally using 11-dehydro-thromboxane B2 (11 DTX) as a measuring index. 11 DTX is a major long-lived metabolite formed from thromboxane (TX) B2, and is said to be a more reliable parameter for detecting TXA2 production in biological systems. In t...
Article
In order to preserve the frontotemporal branch of the facial nerve in frontotemporal and trans-zygomatic craniotomies, electromyographic responses from the facial muscles were recorded preoperatively. Incising the frontotemporal branch of the facial nerve could be avoided by identifying the crossing point of the frontotemporal branch of the facial...
Article
Postoperative MR findings of eleven acoustic neuromas were analyzed. MRI's were able to clearly visualize residual tumor around the 7th and 8th cranial nerves that were left to preserve cranial nerve function, although conventional X ray CT scans often failed to detect it due to artifacts in the parapetrous area. The facial nerves preserved during...
Article
Postoperative magnetic resonance imaging findings related to the vestibulocochlear and facial nerves within the internal auditory canal were analyzed in acoustic neurinomas. T1- and proton-weighted magnetic resonance images showed that the vestibulocochlear nerves distal to the internal auditory meatus increased in signal intensity after surgical i...
Article
Microvascular decompression procedures were carried out to relieve right hemifacial spasm in a 54-year-old man. His facial spasm was satisfactorily cured but he complained of severe vertigo, and slight facial palsy was also shown after the operation. Electronystagmograph disclosed spontaneous horizontal and rotatory nystagmus toward the non-operate...
Article
The methods to record evoked electromyographic responses by micro malleable clip electrodes applied directly to the extraocular muscles are described. This electrophysiological monitoring enables surgeons to localize the ocular motor nerves accurately in the skull base of the middle, posterior fossa, and orbit. In cavernous sinus surgery, electrica...
Article
The 7th and 8th cranial nerves were shifted in the cerebellopontine (CP) angle of dogs by cerebellar retractions that were similar to those performed in humans with monitoring of auditory evoked brainstem responses (ABR). Postoperatively, the vestibular, facial nerves, and brainstem were histologically examined. Caudal-to-rostral shifts of the nerv...
Article
To elucidate how surgery in the cerebellopontine (CP) angle may cause vestibular and facial nerve injury, the 7th and 8th cranial nerves of dogs were manipulated as in human surgery along with monitoring of auditory evoked brain stem responses. Postoperatively, histological examinations were performed to investigate the effect of the surgical manip...
Article
A 61-year-old female was referred because of headache and gait disturbance. A computed tomography (CT) scan revealed a midline isodense mass lesion. The limit of the tumor was equivocal even after administration of contrast medium. Magnetic resonance imaging (MRI) study, however, clearly showed the relationship between the tumor and the surrounding...
Article
This report elucidates our experiences on acoustic neuroma surgery, in which auditory function was lost postoperatively, although conservation of hearing had been intended preoperatively. Five ears from four patients (two ears: unilateral, three ears from bilateral acoustic neuromas) were operated on via standard retromastoid route, with monitoring...
Article
A 61-year-old female was referred because of headache and gait disturbance. A computed tomography (CT) scan revealed a midline isodense mass lesion. The limit of the tumor was equivocal even after administration of contrast medium. Magnetic resonance imaging (MRI) study, however, clearly showed the relationship between the tumor and the surrounding...
Article
Acoustic neuroma in bilateral cerebellopontine angle regions developed in a patient with von Recklinghausen's disease was removed under monitoring auditory evoked potentials. Long term follow up of the auditory evoked potentials of this patient revealed that the amplitudes of auditory evoked potentials were gradually reduced over one and half month...
Article
A 15-year-old boy was referred to our department due to left abducens palsy and trigeminal neuralgia. CT scans that had been taken fourteen months before this referral failed to disclose any abnormality. CT scans taken on admission, however, demonstrated an irregular calcified lesion in the left parasellar region. This implied that some ossifying p...
Article
Responses from the dorsal surface of the exposed dorsal column nuclei (DCN) in baboons and a monkey (Macaca fascicularis) were recorded in response to electrical stimulation of the posterior tibial nerve at the ankle, the common peroneal nerve at the knee, the sciatic nerve, the spinal cord at T10, and the median nerve at the wrist. Recordings of f...
Article
Cochlear nerve injuries caused by surgical manipulation in the cerebellopontine (CP) angle were electrophysiologically and morphologically investigated in dogs. Operative procedures similar to those performed in the CP angle in humans were performed. Lateral-to-medial retraction of the cerebellar hemispheres applied traction force to the cochlear n...
Article
A flexible copper spatula, usually used by us as retractor in brain surgery, was easily converted to become self-retaining without any other apparatus, by a simple minor modification.
Article
It is said that lateral-to-medial retraction of the cerebellar hemisphere is hazardous because, by this retraction, avulsion injury of the cochlear nerve and internal auditory artery may be caused. Caudal-to-rostral retraction of the cerebellar hemisphere is, therefore, recommended in operations in the CP angle such as microvascular decompression p...
Article
Cochlear nerve injuries caused by surgical manipulation in the cerebellopontine (CP) angle were electrophysiologically and morphologically investigated in dogs. Operative procedures similar to those performed in the CP angle in humans were performed. Lateral-to-medial retraction of the cerebellar hemispheres applied traction force to the cochlear n...
Article
: The current tendency in acoustic neuroma surgery to attempt the preservation of hearing function and the problem of accidental hearing loss caused by microsurgical neurovascular decompression operations for hemifacial spasm or trigeminal neuralgia prompted us to study the exact surgical vulnerability of the auditory system. The surgical procedure...
Article
The effect of traction injury to the eighth nerve on the compound action potentials (CAPs) recorded from the exposed nerve in response to tonebursts and click sounds was compared to responses elicited by continuous tones and noise that were amplitude-modulated with pseudorandom noise. Responses to the continuous sounds were presented in the form of...
Article
Cochlear nerve injuries caused by manipulations in the cerebellopontine angle were electrophysiologically and morphologically investigated in dogs. Operative procedures similar to those performed in the cerebellopontine angle of humans were applied in dogs. Auditory-evoked potentials were recorded throughout the experiments. Postoperatively, the te...
Article
Full-text available
Cochlear nerve injuries caused by manipulations in the cerebellopontine angle were electrophysiologically and morphologically investigated using dogs. Compression injuries were developed at the portions of the cochlear nerves that were directly retracted by a retractor. The blood vessels supplying the cochlear nerve trunk easily ruptured and the Sc...
Article
Full-text available
Cochlear nerve injuries caused by the manipulations in the cerebellopontine angle were electrophysiologically and morphologically investigated in rhesus monkeys. The brainstem auditory evoked potentials and/or the compound action potentials recorded from the intracranial portions of the cochlear nerve so often deteriorated due to cerebellar retract...
Article
Full-text available
Cerebellar retractions were performed in the cerebellopontine (CP) angle of rhesus monkeys to study the relationship between changes in brainstem auditory evoked potentials (BAEP) and/or compound action potentials (CAP) from the cochlear nerve, and morphological changes in the cochlear nerve in order to investigate the nature of cochlear nerve inju...
Article
The effect of manipulations in the cerebellopontine (CP) angle on the cochlear nerve was studied in 12 rhesus monkeys to elucidate how surgical procedures in the CP angle may affect the peripheral auditory system. Brain stem auditory evoked potentials and compound action potentials from the cochlear nerve were recorded throughout the experiments an...
Article
Full-text available
Changes in the response from the cochlear nerve in dogs resulting from cerebellopontine angle (CPA) manipulations were correlated with histological changes in the nerve. The aim of this study was to determine the mechanisms underlying hearing deficits incurred as a result of manipulations in the CPA. Compound action potentials (CAP) were recorded f...