The Experts below are selected from a list of 9129 Experts worldwide ranked by ideXlab platform

Nobuhito Saito - One of the best experts on this subject based on the ideXlab platform.

  • Intraoperative Monitoring of cortically recorded visual response for posterior visual pathway
    Journal of Neurosurgery, 2010
    Co-Authors: Kensuke Kawai, Kyousuke Kamada, Nobuhito Saito
    Abstract:

    Object Intraoperative Monitoring of visual evoked potentials (VEPs) has been regarded as having limited significance for the preservation of visual function during neurosurgical procedures, mainly due to its poor spatial resolution and signal-to-noise ratio. The authors evaluated the usefulness of cortically recorded VEPs, instead of the usual scalp VEPs, as Intraoperative Monitoring focusing on the posterior visual pathway. Methods In 17 consecutive patients who underwent microsurgical procedures for lesions near the posterior visual pathway, cortical responses were recorded using 1-Hz flashing light-emitting diodes and subdural strip electrodes after induction of general anesthesia with sevoflurane or propofol. The detectability and waveform of the initial response, stability, and changes during microsurgical manipulations were analyzed in association with the position of electrodes and postoperative changes in visual function. Results Initial VEPs were detected in 82% of all patients. The VEPs were det...

  • Intraoperative Monitoring of cortically recorded visual response for posterior visual pathway
    Journal of Neurosurgery, 2010
    Co-Authors: Kensuke Kawai, Kyousuke Kamada, Nobuhito Saito
    Abstract:

    Object Intraoperative Monitoring of visual evoked potentials (VEPs) has been regarded as having limited significance for the preservation of visual function during neurosurgical procedures, mainly due to its poor spatial resolution and signal-to-noise ratio. The authors evaluated the usefulness of cortically recorded VEPs, instead of the usual scalp VEPs, as Intraoperative Monitoring focusing on the posterior visual pathway. Methods In 17 consecutive patients who underwent microsurgical procedures for lesions near the posterior visual pathway, cortical responses were recorded using 1-Hz flashing light-emitting diodes and subdural strip electrodes after induction of general anesthesia with sevoflurane or propofol. The detectability and waveform of the initial response, stability, and changes during microsurgical manipulations were analyzed in association with the position of electrodes and postoperative changes in visual function. Results Initial VEPs were detected in 82% of all patients. The VEPs were det...

Tatsuya Sasaki - One of the best experts on this subject based on the ideXlab platform.

  • Intraoperative Monitoring of visual evoked potential introduction of a clinically useful method
    Journal of Neurosurgery, 2010
    Co-Authors: Tatsuya Sasaki, Tsuyoshi Ichikawa, Kyouichi Suzuki, Takeshi Itakura, Hiromichi Kasuya, Ryoji Munakata, Hiroyuki Muramatsu, Taku Sato, Yuji Endo, Jun Sakuma
    Abstract:

    Object To obtain a clinically useful method of Intraoperative Monitoring of visual evoked potentials (VEPs), the authors developed a new light-stimulating device and introduced electroretinography (ERG) to ascertain retinal light stimulation after induction of venous anesthesia. Methods The new stimulating device consists of 16 red light–emitting diodes embedded in a soft silicone disc to avoid deviation of the light axis after frontal scalp-flap reflection. After induction of venous anesthesia with propofol, the authors performed ERG and VEP recording in 100 patients (200 eyes) who were at Intraoperative risk for visual impairment. Results Stable ERG and VEP recordings were obtained in 187 eyes. In 12 eyes, stable ERG data were recorded but VEPs could not be obtained, probably because all 12 eyes manifested severe preoperative visual dysfunction. The disappearance of ERG data and VEPs in the 13th eye after frontal scalp-flap reflection suggested technical failure attributable to deviation of the light ax...

  • Intraoperative Monitoring of visual evoked potentials
    Masui. The Japanese journal of anesthesiology, 2006
    Co-Authors: Tatsuya Sasaki, Namio Kodama, Masato Matsumoto, Tsuyoshi Ichikawa, Jun Sakuma, Kyouichi Suzuki, Takeshi Itakura, Masahiro Murakawa
    Abstract:

    Our success rate of Intraoperative Monitoring of visual evoked potential (VEP) had been approximately 30% in the past. In order to improve recording rate of Intraoperative VEP, we developed a new stimulating device using high power light emitting diodes. Electroretinogram was simultaneously recorded to understand whether flash stimulation reached the retina. In addition, total venous anesthesia with propofol was used to avoid the adverse effect of inhalation anesthesia. We report the results after introduction of these improvements. Intraoperative Monitoring of VEP was attempted in 35 cases. We evaluated success rate of VEP recording, correlation between VEP findings and postoperative visual function, and reasons why recording was not successful. Stable and reproducible waveforms were obtained in 59 sides (84%). Two cases, whose VEP deteriorated Intraoperatively, developed postoperative visual disturbance: In 11 sides (16%), stable waveforms were not obtained. There were two main causes. In 8 sides out of 11, the cause was attributed to pre-existing severe visual disturbance. In these 8 sides, VEP in the awake state was not recordable or was recordable, but with very low amplitudes under 1 microV. In the other 3 sides, the cause was attributed to movement of a stimulating device by reflecting the fronto-temporal scalp flap. In conclusion, the successful recording rate was increased to 84% from approximately 30%, after introduction of various trials. We need further improvement in recording Intraoperative VEP to establish a reliable Intraoperative Monitoring method for VEP.

  • experimental study of medullary trigeminal evoked potentials development of a new method of Intraoperative Monitoring of the medulla oblongata
    Journal of Neurosurgery, 2000
    Co-Authors: Tomoyoshi Oikawa, Masato Matsumoto, Tatsuya Sasaki, Namio Kodama
    Abstract:

    Object. The goal of this study was to develop a new method of Intraoperative Monitoring of functions located in the lateral portion of the medulla oblongata. Based on the fact that the spinal trigeminal nucleus and tract are located in the lateral portion of the medulla oblongata, the authors intended to investigate the efficacy of trigeminal evoked potentials (TEPs) in Intraoperative Monitoring for assessing functions of the medulla oblongata. Methods. Trigeminal evoked potentials induced by electrical stimulation of the infraorbital nerve were recorded from the dorsolateral portion of the medulla oblongata (M-TEP) and the cerebral sensory cortex (C-TEP) in dogs. When the lateral one-sixth portion of the medulla was cut, the amplitude of the M-TEP decreased markedly, but the amplitude of the C-TEP and the somatosensory evoked potential (SSEP) did not decrease. When the lateral one-third portion of the medulla was cut, the amplitude of the SSEP decreased, but that of the C-TEP showed no change. When the medulla was retracted, the amplitude of the M-TEP was more sensitive than that of SSEP. Pathological examinations revealed that retraction force less than 10 g and a reduction in the amplitude of the M-TEP less than 50% were safe. Conclusions. These results suggest that M-TEPs obtained from the dorsolateral portion of the medulla oblongata by electrical stimulation of the trigeminal nerve are clinically applicable as a new means of Intraoperative Monitoring of the functions of the medulla oblongata.

Kensuke Kawai - One of the best experts on this subject based on the ideXlab platform.

  • Intraoperative Monitoring of cortically recorded visual response for posterior visual pathway
    Journal of Neurosurgery, 2010
    Co-Authors: Kensuke Kawai, Kyousuke Kamada, Nobuhito Saito
    Abstract:

    Object Intraoperative Monitoring of visual evoked potentials (VEPs) has been regarded as having limited significance for the preservation of visual function during neurosurgical procedures, mainly due to its poor spatial resolution and signal-to-noise ratio. The authors evaluated the usefulness of cortically recorded VEPs, instead of the usual scalp VEPs, as Intraoperative Monitoring focusing on the posterior visual pathway. Methods In 17 consecutive patients who underwent microsurgical procedures for lesions near the posterior visual pathway, cortical responses were recorded using 1-Hz flashing light-emitting diodes and subdural strip electrodes after induction of general anesthesia with sevoflurane or propofol. The detectability and waveform of the initial response, stability, and changes during microsurgical manipulations were analyzed in association with the position of electrodes and postoperative changes in visual function. Results Initial VEPs were detected in 82% of all patients. The VEPs were det...

  • Intraoperative Monitoring of cortically recorded visual response for posterior visual pathway
    Journal of Neurosurgery, 2010
    Co-Authors: Kensuke Kawai, Kyousuke Kamada, Nobuhito Saito
    Abstract:

    Object Intraoperative Monitoring of visual evoked potentials (VEPs) has been regarded as having limited significance for the preservation of visual function during neurosurgical procedures, mainly due to its poor spatial resolution and signal-to-noise ratio. The authors evaluated the usefulness of cortically recorded VEPs, instead of the usual scalp VEPs, as Intraoperative Monitoring focusing on the posterior visual pathway. Methods In 17 consecutive patients who underwent microsurgical procedures for lesions near the posterior visual pathway, cortical responses were recorded using 1-Hz flashing light-emitting diodes and subdural strip electrodes after induction of general anesthesia with sevoflurane or propofol. The detectability and waveform of the initial response, stability, and changes during microsurgical manipulations were analyzed in association with the position of electrodes and postoperative changes in visual function. Results Initial VEPs were detected in 82% of all patients. The VEPs were det...

Jun Sakuma - One of the best experts on this subject based on the ideXlab platform.

  • Intraoperative Monitoring of visual evoked potential introduction of a clinically useful method
    Journal of Neurosurgery, 2010
    Co-Authors: Tatsuya Sasaki, Tsuyoshi Ichikawa, Kyouichi Suzuki, Takeshi Itakura, Hiromichi Kasuya, Ryoji Munakata, Hiroyuki Muramatsu, Taku Sato, Yuji Endo, Jun Sakuma
    Abstract:

    Object To obtain a clinically useful method of Intraoperative Monitoring of visual evoked potentials (VEPs), the authors developed a new light-stimulating device and introduced electroretinography (ERG) to ascertain retinal light stimulation after induction of venous anesthesia. Methods The new stimulating device consists of 16 red light–emitting diodes embedded in a soft silicone disc to avoid deviation of the light axis after frontal scalp-flap reflection. After induction of venous anesthesia with propofol, the authors performed ERG and VEP recording in 100 patients (200 eyes) who were at Intraoperative risk for visual impairment. Results Stable ERG and VEP recordings were obtained in 187 eyes. In 12 eyes, stable ERG data were recorded but VEPs could not be obtained, probably because all 12 eyes manifested severe preoperative visual dysfunction. The disappearance of ERG data and VEPs in the 13th eye after frontal scalp-flap reflection suggested technical failure attributable to deviation of the light ax...

  • Intraoperative Monitoring of visual evoked potentials
    Masui. The Japanese journal of anesthesiology, 2006
    Co-Authors: Tatsuya Sasaki, Namio Kodama, Masato Matsumoto, Tsuyoshi Ichikawa, Jun Sakuma, Kyouichi Suzuki, Takeshi Itakura, Masahiro Murakawa
    Abstract:

    Our success rate of Intraoperative Monitoring of visual evoked potential (VEP) had been approximately 30% in the past. In order to improve recording rate of Intraoperative VEP, we developed a new stimulating device using high power light emitting diodes. Electroretinogram was simultaneously recorded to understand whether flash stimulation reached the retina. In addition, total venous anesthesia with propofol was used to avoid the adverse effect of inhalation anesthesia. We report the results after introduction of these improvements. Intraoperative Monitoring of VEP was attempted in 35 cases. We evaluated success rate of VEP recording, correlation between VEP findings and postoperative visual function, and reasons why recording was not successful. Stable and reproducible waveforms were obtained in 59 sides (84%). Two cases, whose VEP deteriorated Intraoperatively, developed postoperative visual disturbance: In 11 sides (16%), stable waveforms were not obtained. There were two main causes. In 8 sides out of 11, the cause was attributed to pre-existing severe visual disturbance. In these 8 sides, VEP in the awake state was not recordable or was recordable, but with very low amplitudes under 1 microV. In the other 3 sides, the cause was attributed to movement of a stimulating device by reflecting the fronto-temporal scalp flap. In conclusion, the successful recording rate was increased to 84% from approximately 30%, after introduction of various trials. We need further improvement in recording Intraoperative VEP to establish a reliable Intraoperative Monitoring method for VEP.

Namio Kodama - One of the best experts on this subject based on the ideXlab platform.

  • Intraoperative Monitoring of visual evoked potentials
    Masui. The Japanese journal of anesthesiology, 2006
    Co-Authors: Tatsuya Sasaki, Namio Kodama, Masato Matsumoto, Tsuyoshi Ichikawa, Jun Sakuma, Kyouichi Suzuki, Takeshi Itakura, Masahiro Murakawa
    Abstract:

    Our success rate of Intraoperative Monitoring of visual evoked potential (VEP) had been approximately 30% in the past. In order to improve recording rate of Intraoperative VEP, we developed a new stimulating device using high power light emitting diodes. Electroretinogram was simultaneously recorded to understand whether flash stimulation reached the retina. In addition, total venous anesthesia with propofol was used to avoid the adverse effect of inhalation anesthesia. We report the results after introduction of these improvements. Intraoperative Monitoring of VEP was attempted in 35 cases. We evaluated success rate of VEP recording, correlation between VEP findings and postoperative visual function, and reasons why recording was not successful. Stable and reproducible waveforms were obtained in 59 sides (84%). Two cases, whose VEP deteriorated Intraoperatively, developed postoperative visual disturbance: In 11 sides (16%), stable waveforms were not obtained. There were two main causes. In 8 sides out of 11, the cause was attributed to pre-existing severe visual disturbance. In these 8 sides, VEP in the awake state was not recordable or was recordable, but with very low amplitudes under 1 microV. In the other 3 sides, the cause was attributed to movement of a stimulating device by reflecting the fronto-temporal scalp flap. In conclusion, the successful recording rate was increased to 84% from approximately 30%, after introduction of various trials. We need further improvement in recording Intraoperative VEP to establish a reliable Intraoperative Monitoring method for VEP.

  • experimental study of medullary trigeminal evoked potentials development of a new method of Intraoperative Monitoring of the medulla oblongata
    Journal of Neurosurgery, 2000
    Co-Authors: Tomoyoshi Oikawa, Masato Matsumoto, Tatsuya Sasaki, Namio Kodama
    Abstract:

    Object. The goal of this study was to develop a new method of Intraoperative Monitoring of functions located in the lateral portion of the medulla oblongata. Based on the fact that the spinal trigeminal nucleus and tract are located in the lateral portion of the medulla oblongata, the authors intended to investigate the efficacy of trigeminal evoked potentials (TEPs) in Intraoperative Monitoring for assessing functions of the medulla oblongata. Methods. Trigeminal evoked potentials induced by electrical stimulation of the infraorbital nerve were recorded from the dorsolateral portion of the medulla oblongata (M-TEP) and the cerebral sensory cortex (C-TEP) in dogs. When the lateral one-sixth portion of the medulla was cut, the amplitude of the M-TEP decreased markedly, but the amplitude of the C-TEP and the somatosensory evoked potential (SSEP) did not decrease. When the lateral one-third portion of the medulla was cut, the amplitude of the SSEP decreased, but that of the C-TEP showed no change. When the medulla was retracted, the amplitude of the M-TEP was more sensitive than that of SSEP. Pathological examinations revealed that retraction force less than 10 g and a reduction in the amplitude of the M-TEP less than 50% were safe. Conclusions. These results suggest that M-TEPs obtained from the dorsolateral portion of the medulla oblongata by electrical stimulation of the trigeminal nerve are clinically applicable as a new means of Intraoperative Monitoring of the functions of the medulla oblongata.