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PS-36-10 Neuromonitoring in experimental model of clip compression on the spinal nerve root to characterize the acute nerve root injury
Postersession 37. Spinaland longreflex the motoneurons by the descending volleys which travelled orthodromically. These results may encourage us to apply the method to the clinical situations to monitor the integrated motor tracts intraoperatively.
I PS-36-101 Neuromonitoring in experimental model of clip compression on the spinal nerve root to characterize the acute nerve root injury I-Ming Jou 1, Rucy-Mo Lin 1, Kuo-An Lai 1, Hideo Matsuda 2.
1Department of orthopedics, National Cheng-Kung University Medical Center, Tainan, Taiwan, ROC; 2Koshigawa Orthopedic Hospital, Osaka, Japan With the advent of transpedicular screw system, an increasing risk of injury to the spinal root due to the passage of screws is not surprising. Although both experimental model and clinical application in intraoperative neuromonitoring of spinal cord function using several neurophysiologicai surveillance techniques have been well established, acute spinal root injury remains to be obscure. The purpose of this study was to determine if acute spinal cord injury models (weight, clip compression, acute balloon inflation) can also be used to make the reversible and irreversible damage to spinal nerve root and verify in neuromonitoring and histologic studies. Adult New Zealand rabbit was anesthetized by intravenous pentobarbiturate and muscle relaxant with ventilator for respiratory care. After laminectomies from L2 to L7, the blades of the aneurysm clip were passed extradurally anteriorly and posteriorly around the exposed root (L6, by radiological identification) and the clip was rapidly released for seconds and removed. Different neuromonitoring models were used to record the changes in time sequence before and after the clip compression. The damaged was also removed en block for histologic study after perfusion and fixation. Results demonstrated that (1) direct compression by an aneurysm clip in different time duration from 5 to 30 seconds can produce delay in latency and decrease in amplitude of different degrees and recovery pattern; (2) compared with SSEP, MEP, ESCP (evoked spinal cord potential, elicited by stimulation of the sciatic nerve) is the most reliable tool in neuromonitoring during acute nerve root compression; (3) there were significant differences in change of latency and amplitude with different compression duration, which also have a certain correlation with histologic study of the damaged nerve roots.
I PS-36-11 I Intraoperative electrodiadnosis for bracial plexus Injury Yasunori Fuchigami 1, Sinya Kawai 1, Kazuteru Doi 1, Gen Shiraishi 1, Takashi Itho 1, Kazuo Kaneko 1, Tadaaki Hashida 1, Hiroyuki Kawamura 1, Akira Oofuji i.
1Department of Orthopedic Surgery, School of Medicine, Yamaguchi University, 1144 Kogushi, Ube, Japan In order to diagnose the level of the nerve root injury, we recorded spinal evoked potentials (SpEP) intraoperatively in the 19 cases of brachial plexus injury. Recording electrode was the catheter electrode which had been inserted in the epidural space at the day before operation. Nerve roots were stimulated directly after exposed. No response were obtained after stimulation of damaged nerve roots whose findings of myelogram showed abnormal or whose macroscopic findings were not normal. In seven cases, C5 root was stimulated. Peak to peak amplitude of SpEPs were 0/~V to 45 #V. Significant difference was found between poor response group (less than 5/zV) and good response group (over 5/zV). We had five cases of nerve transplantation from C5 root to peripheral
S177
nerve. We recorded good responses (amplitude 8/zV, 15/zV) in two cases from epidural electrode after stimulation of C5 root. One year later after operation, motor unit potentials from deltoid were appeared in these two cases. We recorded no response in two cases and very small response (less than 5/zV) in one case from epidural electrode after stimulation of C5 root. One year later after operation, few motor unit potentials were obtained in those three cases, lnorder to recognize the functional continuity between Spinal cord and nerve root in brachial plexus injury, intraoperative SpEP recording was most useful.
PS-36-12] General anesthetic effects on compound muscle action potentials elicited by single or dual spinal stimulation Hiroshi Yamada 1, Tetsuya Tamaki 1, Hiroaki Nishiura 1, Ensor E. Transfeldt 2, Fernando Torres 3, Paul A. laizzo 4, Benjamin A. Taylor 5. 1Department of Orthopedic Surgery, Wakayama
Medical College; 2Department of Orthopedic Surgery, 3Dept. of Neurology, 4Department of Anesthesiology and Physiology, University of Minnesota; 5 The Royal National Orthopedic Hospital Trust This study was performed to determine the optimal parameters of spinal stimulation for the reproducible monitoring of muscle compound action potentials during general anesthesia as a means to evaluate motor tract integrity. Single spinal stimulations of various intensities were contrasted to dual stimulations of various interpulse durations. Double pulse stimulations with a 2 ms interpulse interval resulted in the largest increase in muscle potential amplitudes relative to single pulse stimulations of a similar intensity. Using optimal single or double stimulation protocols the relative amplitudes of muscle potentials were monitored during various anesthetic depths with one of the following agents: halothane, enflurane, isoflurane or propofol. Muscle potential amplitudes following either double or single pulse stimulation were greatest during propofol anesthesia. Amplitudes of recorded potentials were the same following double pulse stimulations at concentrations of 50, 100, 150 and 200 /zg/kg/h, whereas they decreased by 50% following single pulse stimulation. Relative to the amplitudes of muscle potentials recorded using propofol, the effects of the volatile anesthetics were dramatic, especially with halothane being the most potent at a given concentration (0.5, 1.0, 1.5, or 2.0%). It was concluded that double pulse stimulation can be used to facilitate the amplitude of evoked compound muscle action potentials, but only will anesthetic effects be minimal when propofol is used.
PS-37. SPINAL AND LONG REFLEX
I PS-37-1 ] Clinical evaluations of patellar tendon reflexes and T-waves Hideo Yoshioka 1, Ryouji Hashimoto 1, Hidemune Kyou 1, Takasi Tsuji 1, Yasuyuki Koishi 1, Seizaburou Arita 2.
l Department of Orthopedic Surgery, Yodogawa Christian Hospital; 2Department of Mathematics, Kansai Medical College, Japan T-waves of patellar tendon reflexes were examined in 50 control subjects (C-group), 28 myelopathy patients (M-group) and 16 lower motor neuron deficit patients (R-group). By clinical grading of the reflex whether increased, normal or reduced, these groups were subdivided into C-normal (38 cases), C-increased (2), Creduced (10), M-increased (23), M-normal (5), R-reduced (14)
I PS-36-101 Neuromonitoring in experimental model of clip compression on the spinal nerve root to characterize the acute nerve root injury I-Ming Jou 1, Rucy-Mo Lin 1, Kuo-An Lai 1, Hideo Matsuda 2.
1Department of orthopedics, National Cheng-Kung University Medical Center, Tainan, Taiwan, ROC; 2Koshigawa Orthopedic Hospital, Osaka, Japan With the advent of transpedicular screw system, an increasing risk of injury to the spinal root due to the passage of screws is not surprising. Although both experimental model and clinical application in intraoperative neuromonitoring of spinal cord function using several neurophysiologicai surveillance techniques have been well established, acute spinal root injury remains to be obscure. The purpose of this study was to determine if acute spinal cord injury models (weight, clip compression, acute balloon inflation) can also be used to make the reversible and irreversible damage to spinal nerve root and verify in neuromonitoring and histologic studies. Adult New Zealand rabbit was anesthetized by intravenous pentobarbiturate and muscle relaxant with ventilator for respiratory care. After laminectomies from L2 to L7, the blades of the aneurysm clip were passed extradurally anteriorly and posteriorly around the exposed root (L6, by radiological identification) and the clip was rapidly released for seconds and removed. Different neuromonitoring models were used to record the changes in time sequence before and after the clip compression. The damaged was also removed en block for histologic study after perfusion and fixation. Results demonstrated that (1) direct compression by an aneurysm clip in different time duration from 5 to 30 seconds can produce delay in latency and decrease in amplitude of different degrees and recovery pattern; (2) compared with SSEP, MEP, ESCP (evoked spinal cord potential, elicited by stimulation of the sciatic nerve) is the most reliable tool in neuromonitoring during acute nerve root compression; (3) there were significant differences in change of latency and amplitude with different compression duration, which also have a certain correlation with histologic study of the damaged nerve roots.
I PS-36-11 I Intraoperative electrodiadnosis for bracial plexus Injury Yasunori Fuchigami 1, Sinya Kawai 1, Kazuteru Doi 1, Gen Shiraishi 1, Takashi Itho 1, Kazuo Kaneko 1, Tadaaki Hashida 1, Hiroyuki Kawamura 1, Akira Oofuji i.
1Department of Orthopedic Surgery, School of Medicine, Yamaguchi University, 1144 Kogushi, Ube, Japan In order to diagnose the level of the nerve root injury, we recorded spinal evoked potentials (SpEP) intraoperatively in the 19 cases of brachial plexus injury. Recording electrode was the catheter electrode which had been inserted in the epidural space at the day before operation. Nerve roots were stimulated directly after exposed. No response were obtained after stimulation of damaged nerve roots whose findings of myelogram showed abnormal or whose macroscopic findings were not normal. In seven cases, C5 root was stimulated. Peak to peak amplitude of SpEPs were 0/~V to 45 #V. Significant difference was found between poor response group (less than 5/zV) and good response group (over 5/zV). We had five cases of nerve transplantation from C5 root to peripheral
S177
nerve. We recorded good responses (amplitude 8/zV, 15/zV) in two cases from epidural electrode after stimulation of C5 root. One year later after operation, motor unit potentials from deltoid were appeared in these two cases. We recorded no response in two cases and very small response (less than 5/zV) in one case from epidural electrode after stimulation of C5 root. One year later after operation, few motor unit potentials were obtained in those three cases, lnorder to recognize the functional continuity between Spinal cord and nerve root in brachial plexus injury, intraoperative SpEP recording was most useful.
PS-36-12] General anesthetic effects on compound muscle action potentials elicited by single or dual spinal stimulation Hiroshi Yamada 1, Tetsuya Tamaki 1, Hiroaki Nishiura 1, Ensor E. Transfeldt 2, Fernando Torres 3, Paul A. laizzo 4, Benjamin A. Taylor 5. 1Department of Orthopedic Surgery, Wakayama
Medical College; 2Department of Orthopedic Surgery, 3Dept. of Neurology, 4Department of Anesthesiology and Physiology, University of Minnesota; 5 The Royal National Orthopedic Hospital Trust This study was performed to determine the optimal parameters of spinal stimulation for the reproducible monitoring of muscle compound action potentials during general anesthesia as a means to evaluate motor tract integrity. Single spinal stimulations of various intensities were contrasted to dual stimulations of various interpulse durations. Double pulse stimulations with a 2 ms interpulse interval resulted in the largest increase in muscle potential amplitudes relative to single pulse stimulations of a similar intensity. Using optimal single or double stimulation protocols the relative amplitudes of muscle potentials were monitored during various anesthetic depths with one of the following agents: halothane, enflurane, isoflurane or propofol. Muscle potential amplitudes following either double or single pulse stimulation were greatest during propofol anesthesia. Amplitudes of recorded potentials were the same following double pulse stimulations at concentrations of 50, 100, 150 and 200 /zg/kg/h, whereas they decreased by 50% following single pulse stimulation. Relative to the amplitudes of muscle potentials recorded using propofol, the effects of the volatile anesthetics were dramatic, especially with halothane being the most potent at a given concentration (0.5, 1.0, 1.5, or 2.0%). It was concluded that double pulse stimulation can be used to facilitate the amplitude of evoked compound muscle action potentials, but only will anesthetic effects be minimal when propofol is used.
PS-37. SPINAL AND LONG REFLEX
I PS-37-1 ] Clinical evaluations of patellar tendon reflexes and T-waves Hideo Yoshioka 1, Ryouji Hashimoto 1, Hidemune Kyou 1, Takasi Tsuji 1, Yasuyuki Koishi 1, Seizaburou Arita 2.
l Department of Orthopedic Surgery, Yodogawa Christian Hospital; 2Department of Mathematics, Kansai Medical College, Japan T-waves of patellar tendon reflexes were examined in 50 control subjects (C-group), 28 myelopathy patients (M-group) and 16 lower motor neuron deficit patients (R-group). By clinical grading of the reflex whether increased, normal or reduced, these groups were subdivided into C-normal (38 cases), C-increased (2), Creduced (10), M-increased (23), M-normal (5), R-reduced (14)