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Yamamoto N, Kobashi H, Shiba M, Itoh T. Efficacy and limitations of intraoperative spinal cord monitoring using nasopharyngeal tube electrodes. J Neurosurg Spine 2010; 13:200-10. [DOI: 10.3171/2010.3.spine08298] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Motor evoked potentials are widely used for intraoperative spinal cord monitoring. However, there are problems with anesthetic constraints and high trial-by-trial variability of compound muscle action potential amplitude in muscle motor evoked potential monitoring. It is difficult to determine when to warn the surgeon of an occurrence of spinal cord risk. A method of estimation for motor function in the spinal cord has not been established. To monitor spinal cord function with reliable evoked potentials, including the upper cervical spinal cord and the ventral spinal cord, the authors developed a nasopharyngeal tube electrode that can be placed in front of the upper and ventral cervical spinal cord. The purpose of this study was to investigate the origins and pathways of descending or ascending spinal cord evoked potentials (SCEPs) elicited with this electrode, and the usefulness and limitations of this method.
Methods
A nasopharyngeal tube electrode was inserted into the nostril. A catheter electrode was placed in the epidural or subarachnoid space at the thoracic spine. Ventral SCEP was recorded from the thoracic spinal cord after transpharyngeal stimulation, and dorsal SCEP was recorded with the nasopharyngeal electrode after thoracic spinal cord stimulation. There was no restriction of anesthetic technique in recording. When the amplitude of either of the SCEPs declined to 80% of the baseline, a warning was provided to the surgeon during the observed operative procedure. At the end of surgery, less than 50% or more than 30% of the baseline amplitude was considered a significant change in both SCEPs. The sensitivity and specificity for both SCEPs to detect neurological deterioration were calculated.
Results
The electrode provided noninvasive access to the ventral cervicomedullary junction. The SCEPs showed stable responses. A response change was only observed in situations involving a risky procedure for the spinal cord. Ventral SCEPs showed high sensitivity (73.1%) for identifying patients with new neurological deficits or an exacerbation of preexisting neurological deficits after surgery, but dorsal SCEPs showed lower sensitivity (46.1%) in the total number of cases. Both SCEPs showed high specificities. The sensitivities of ventral SCEP, dorsal SCEP, and either SCEP were 100.0%, 50.0%, and 100.0% for the upper cervical spinal cord, 33.3%, 0%, and 55.6% for the lower cervical spinal cord, and 77.8%, 64.7%, and 88.2% for the thoracic spinal cord.
Conclusions
Combined recording of both SCEPs estimated the ventral and dorsal white matter function in the spinal cord. Measuring the SCEPs with the nasopharyngeal electrode can be another useful approach for upper cervical and thoracic spinal cord monitoring. Ventral SCEP was more reliable for monitoring postoperative spinal cord function than dorsal SCEP. Ventral SCEP does not estimate the gray matter and spinal root functions in the lower cervical spinal cord.
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Juvonen T, Biancari F, Rimpiläinen J, Satta J, Rainio P, Kiviluoma K. Strategies for Spinal Cord Protection during Descending Thoracic and Thoracoabdominal Aortic Surgery: Up-to-date Experimental and Clinical Results - A review. SCAND CARDIOVASC J 2009. [DOI: 10.1080/cdv.36.3.136.160] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Kakinohana M, Nakamura S, Fuchigami T, Sugahara K. Transcranial motor-evoked potentials monitoring can detect spinal cord ischemia more rapidly than spinal cord-evoked potentials monitoring during aortic occlusion in rats. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2006; 16:787-93. [PMID: 16804674 PMCID: PMC2200716 DOI: 10.1007/s00586-006-0165-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2005] [Revised: 05/03/2006] [Accepted: 05/23/2006] [Indexed: 11/24/2022]
Abstract
In this study, we evaluated the efficacy of transcranial motor-evoked potentials (tc-MEPs), compared with segmental spinal cord-evoked potentials (SCEPs), for detecting spinal cord ischemia (SCI) and assessed the relationship between neurological outcome and tc-MEPs or SCEPs in the rat aortic occlusion model. In the rats, SCI was induced by aortic occlusion for 10 min with a balloon catheter. At first, tc-MEPs (Group A: n = 6) or segmental SCEPs (Group B: n = 6) was recorded during SCI. Second, in using the quantal bioassay for the relationship between an interval of aortic occlusion and the probability of positive response in tc-MEPs or segmental SCEPs, the P50(MEP) and P50(SCEP) which represent the interval of aortic occlusion associated with 50% probability of assessment of ischemic spinal cord dysfunction by tc-MEP and SCEP were analyzed. The amplitude of tc-MEPs decreased significantly at 30 s and disappeared completely at 2 min after aortic occlusion. In Group B, it took about 6 min after aortic occlusion to diminish SCEP signal amplitude by approximately 50%. P50(MEP) obtained in the quantal analysis was 0.3 +/- 0.1 min. P50(SCEP) was calculated as 6.2 +/- 0.5 min that was significantly (P < 0.01) longer than P50(MEP). Our data indicated that tc-MEP monitoring could detect the onset of SCI so rapidly in comparison with segmental SCEP monitoring, which could provide therapeutic windows in a surgical approach that includes spinal cord protection.
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Affiliation(s)
- Manabu Kakinohana
- Department of Anesthesiology, University of the Ryukyus, Nishihara, Okinawa, Japan.
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Sueda T, Okada K, Orihashi K, Sugawara Y, Kouchi K, Imai K. Cold blood spinal cord plegia for prediction of spinal cord ischemia during thoracoabdominal aneurysm repair. Ann Thorac Surg 2002; 73:1155-9. [PMID: 11996256 DOI: 10.1016/s0003-4975(02)03405-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND This clinical study was undertaken to evaluate changes in motor evoked potentials (MEPs) during cold blood infusion into a thoracoabdominal aortic aneurysm. We also determined the efficacy of this infusion method for predicting spinal cord injury during thoracoabdominal aortic aneurysmal surgery. METHODS We monitored descending evoked spinal cord potentials (ESCPs), segmental ESCPs, and MEPs during the prosthetic replacement phase of thoracoabdominal aneurysmal surgery. We perfused cold blood (4 degrees C, 300 to 450 mL) into aneurysms after clamping the aorta, while monitoring spinal cord potentials in 6 cases of thoracoabdominal aortic aneurysm. If the spinal cord potentials decreased during infusion of cold blood, we reconstructed the intercostal arteries in the aneurysm. If the potentials did not change during the infusion of cold blood and after the aneurysmectomy, we did not reconstruct the intercostal arteries and ligated all of them. RESULTS Postoperative paraplegia did not occur in any case. The MEPs decreased in amplitude after infusion of cold blood in 3 cases, but amplitude recovered after reconstruction of the intercostal arteries. The other 3 cases did not show any change after infusion of cold blood, and all of the intercostal arteries in the aneurysm were ligated. CONCLUSIONS Cold blood infusion into the aneurysm while monitoring MEPs was a useful adjunct to detect the presence of critical intercostal arteries and to facilitate thoracoabdominal aortic aneurysmal surgery.
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Affiliation(s)
- Taijiro Sueda
- First Department of Surgery, Hiroshima University, School of Medicine, Japan.
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MacDonald DB, Janusz M. An approach to intraoperative neurophysiologic monitoring of thoracoabdominal aneurysm surgery. J Clin Neurophysiol 2002; 19:43-54. [PMID: 11896352 DOI: 10.1097/00004691-200201000-00006] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Thoracoabdominal aneurysm surgery carries an approximate 10% risk of intraoperative paraplegia. Abrupt cord ischemia and the confounding effects of systemic alterations and limb or cerebral ischemia challenges neurophysiologic spinal cord monitoring. This investigation sought a rapid differential monitoring approach to predict or help prevent paraplegia. Thirty-one patients were monitored with motor evoked potentials (MEPs) and median and tibial somatosensory evoked potentials (SSEPs). MEPs involved single-pulse transcranial electrical stimulation with D wave recording (n = 16), arm and leg muscle MEPs following multiple-pulse transcranial electrical stimulation (n = 12), or both (n = 3). D wave recordings required averaging, invasive epidural electrode insertion, and produced both false positives and false negatives. Muscle MEPs were instantaneous and reliably sensitive and specific for cord ischemia. Cortical and peripheral nerve SSEPs provided rapid detection of systemic alterations and cerebral or limb ischemia. Cord and subcortical SSEPs required excessive averaging time. In conclusion, bilateral arm and leg muscle MEPs with median and tibial peripheral nerve and cortical SSEPs provide sufficiently rapid detection and differentiation of cord ischemia from confounding factors. There were two predicted intraoperative spinal cord infarctions (6.5%) and nine circumstantial examples of possible contributions to deficit prevention.
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Affiliation(s)
- David B MacDonald
- Section of Clinical Neurophysiology, Department of Neurosciences, King Faisal Specialist Hospital & Research Center, MBC 76, PO Box 3354, 11211 Riyadh, Saudi Arabia
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Sueda T, Morita S, Okada K, Orihashi K, Shikata H, Matsuura Y. Selective intercostal arterial perfusion during thoracoabdominal aortic aneurysm surgery. Ann Thorac Surg 2000; 70:44-7. [PMID: 10921680 DOI: 10.1016/s0003-4975(00)01440-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND This clinical study evaluated changes in motor evoked potentials (MEP) elicited by direct cerebral cortical stimulation and evoked spinal cord potentials (ESCPs) elicited by direct spinal cord stimulation during selective intercostal arterial perfusion for thoracoabdominal aortic aneurysm (TAAA) repair. We also determined the efficacy of this perfusion method for prevention of paraplegia. METHODS Two kinds of ESCPs and MEPs were monitored during the prosthetic replacement step for TAAA surgeries. We performed selective intercostal arterial perfusion from the T7 intercostal artery to the L1 intercostal artery through a small piece of Dacron graft while monitoring spinal cord potentials in five cases of TAAA. RESULTS The MEP amplitude decreased after clamping the aorta but quickly recovered after selective perfusion of intercostal arteries. Other spinal cord potentials did not change during the reconstruction of intercostal arteries. Postoperative paraplegia or parapalesis did not occur in any of the patients. CONCLUSIONS Monitoring of MEPs during selective intercostal arterial perfusion was a useful adjunct to prevent postoperative paraplegia in TAAA surgery.
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Affiliation(s)
- T Sueda
- First Department of Surgery, Hiroshima University School of Medicine, Japan.
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Gugino LD, Aglio LS, Edmonds Jr HL. Neurophysiological monitoring in vascular surgery. Best Pract Res Clin Anaesthesiol 2000. [DOI: 10.1053/bean.2000.0061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Sueda T, Okada K, Watari M, Orihashi K, Shikata H, Matsuura Y. Evaluation of motor- and sensory-evoked potentials for spinal cord monitoring during thoracoabdominal aortic aneurysm surgery. THE JAPANESE JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY : OFFICIAL PUBLICATION OF THE JAPANESE ASSOCIATION FOR THORACIC SURGERY = NIHON KYOBU GEKA GAKKAI ZASSHI 2000; 48:60-5. [PMID: 10714022 DOI: 10.1007/bf03218086] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To assess the utility of spinal cord monitorings for prediction of spinal cord ischemia, we investigated the role of both motor evoked potentials and sensory evoked potentials during thoracoabdominal aortic aneurysm surgeries. METHODS We monitored two kinds of sensory evoked potentials; descending evoked spinal cord potentials from the lumbar enlargement after cervical spinal cord stimulation and segmental evoked spinal cord potentials at the lumbar enlargement elicited by peroneal nerve stimulation, and motor evoked potentials from the lumbar enlargement elicited by direct subcranial stimulation in 9 thoracoabdomonal aortic aneurysm surgeries. RESULTS Postoperative paraplegia occurred in one case in which the patients died during the perioperative period. One case showed transient paraparesis, but recovered following rehabilitatation. These cases showed a decrease in the amplitude of descending evoked spinal cord potentials and motor evoked potentials. CONCLUSION The recovery of the amplitude of the motor evoked potentials and the descending evoked spinal cord potentials after declamping correlated with the neurologic outcome.
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Affiliation(s)
- T Sueda
- First Department of Surgery, Hiroshima University School of Medicine, Japan
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Abstract
Over the past two decades, intraoperative spinal cord monitoring has matured into a widely used clinical tool. It is used when the spinal cord is at risk for damage during a surgical procedure. This includes orthopedic, neurosurgical, and certain cardiothoracic procedures. Both somatosensory evoked potential (SEP) and direct motor pathway stimulation techniques are available. The SEP techniques are used most widely, are generally accepted, and have been shown to reduce surgical morbidity. A large multicenter study has shown that SEP monitoring reduces postoperative paraplegia by more than 50-60%. Techniques and literature on clinical applications are reviewed in this report.
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Affiliation(s)
- M R Nuwer
- Department of Clinical Neurophysiology, UCLA Medical Center, Reed Neurological Research Center, 710 Westwood Plaza, Room 1-194, Los Angeles, California 90024-6987, USA.
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Fan T, Wang CC, Wang FM, Cheng F, Qiao H, Liu SL, Guo W, Xiang FY. Experimental study of the protection of ischemic preconditioning to spinal cord ischemia. SURGICAL NEUROLOGY 1999; 52:299-305. [PMID: 10511090 DOI: 10.1016/s0090-3019(99)00082-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND Since the advent of ischemic preconditioning in myocardium, more and more attention has been paid to ischemic preconditioning in the central nervous system (CNS). This study was designed to evaluate the protective effect of ischemic preconditioning on spinal cord ischemia. METHODS Interventional neuroradiological techniques were used to induce spinal cord ischemia in a rabbit model. Hydrogen electrode technique was used to determine the regional blood flow of the spinal cord. Catecholamines and their metabolites were measured by high performance liquid chromatography (HPLA). Spinal cord evoked potentials were recorded to show spinal cord neurofunction. RESULTS After 5 minutes ischemic preconditioning with 20 minutes reperfusion, the regional spinal cord blood flow (rSCBF) was increased, as may be seen by the slight increase of catecholamine, especially NE. This is in positive proportion to the cAMP and indicates the enhancement of the metabolic activities of the spinal cord. After 30 minutes of irreversible ischemia, the great increase in catecholamine caused vascular spasm, endotheliocyte fissure, multiple hemorrhagic suffusion, and necrosis, which would injure the spinal cord as a result. The slight increase of the rSCBF and the maintenance of the rSCBF after irreversible ischemia may enhance the protection of ischemic preconditioning to the spinal cord neurofunction, which was proved by spinal cord evoked potentials (SCEPs). CONCLUSIONS Our study showed that 5 minutes of ischemic preconditioning can increase the rSCBF, enhance the tolerance of the spinal cord to irreversible ischemia, and protect the neurofunction of the spinal cord. The biological mechanism of the protective effect of ischemic preconditioning to spinal cord ischemia should be further studied.
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Affiliation(s)
- T Fan
- Beijing Neurosurgical Institute, People's Republic of China
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Affiliation(s)
- M R Nuwer
- Department of Neurology, UCLA School of Medicine, UCLA Medical Center, Los Angeles, California 90024-6987, USA
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Ishimaru S, Kawaguchi S, Koizumi N, Obitsu Y, Ishikawa M. Preliminary report on prediction of spinal cord ischemia in endovascular stent graft repair of thoracic aortic aneurysm by retrievable stent graft. J Thorac Cardiovasc Surg 1998; 115:811-8. [PMID: 9576215 DOI: 10.1016/s0022-5223(98)70360-5] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To predict spinal cord ischemia after endovascular stent graft repair of descending thoracic aortic aneurysms, temporary interruption of the intercostal arteries (including the aneurysm) was performed by placement of a novel retrievable stent graft (Retriever) in the aorta under evoked spinal cord potential monitoring. METHODS From February 1995 to October 1997, endovascular stent graft repair of descending thoracic aortic aneurysms was performed in 49 patients after informed consent was obtained. In 16 patients with aneurysms located in the middle and distal segment of the descending aorta, the Retriever was placed temporarily before stent graft deployment. The Retriever consisted of two units of self-expanding zigzag stents connected in tandem with stainless steel struts. Each strut was collected in a bundle fixed to a pushing rod, and the stent framework was lined with an expanded polytetrafluoroethylene sheet. The Retriever was delivered beyond the aneurysm through a sheath and was retracted into the sheath 20 minutes later. A stent graft for permanent use was deployed in patients whose predeployment test results with the Retriever were favorable. Evoked spinal cord potential was monitored throughout placement of the Retriever and stent grafting until the next day. RESULTS The Retriever was placed in 17 aneurysms in 16 patients. There were no changes in amplitude or latency of evoked spinal cord potential records obtained before or during Retriever placement. After withdrawal of the Retriever, all aneurysms were excluded from circulation immediately after permanent stent grafting. There were no changes in evoked spinal cord potential, nor were neurologic deficits seen after stent graft deployment in any patient. CONCLUSIONS These results suggest that predeployment testing with the Retriever under evoked spinal cord potential monitoring is promising as a predictor of spinal cord ischemia in candidates for stent graft repair of thoracic aortic aneurysms.
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Affiliation(s)
- S Ishimaru
- Second Department of Surgery, Tokyo Medical College, Japan
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Abstract
BACKGROUND Although rare, paralysis secondary to spinal cord ischaemia after aortic aneurysm surgery is a devastating complication. Many papers have been published on this topic but without a clear consensus on the best way of minimizing the problem. Recent articles have included advanced pharmacological approaches and the literature has been reviewed in light of these. METHODS Relevant papers were identified by an extensive text word search of the Medline database and a review of quoted articles. RESULTS Spinal cord complications are commoner after the repair of Crawford type II aneurysms than less extensive aneurysms. The presence of dissection, rupture and prolonged clamp times are associated with an increased incidence. About a quarter of all cord problems develop over 24 h after surgery and this may be due to a reperfusion type injury, although the exact mechanisms are by no means clear. CONCLUSION A combination of rapid surgery, left heart bypass for the repair of more extensive aneurysms, free spinal drainage and the avoidance of postoperative hypoxia and hypotension help to minimize spinal cord ischaemia. No pharmacological agent has yet been shown conclusively to improve outcome in the clinical setting.
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Affiliation(s)
- P Lintott
- Academic Surgical Unit, Imperial College School of Medicine at St Mary's, St Mary's Hospital, London, UK
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Matsuyama K, Chiba Y, Ihaya A, Kimura T, Tanigawa N, Muraoka R. Effect of spinal cord preconditioning on paraplegia during cross-clamping of the thoracic aorta. Ann Thorac Surg 1997; 63:1315-20. [PMID: 9146321 DOI: 10.1016/s0003-4975(97)00104-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Paraplegia is a devastating complication of operations for thoracic or thoracoabdominal aneurysms. Preconditioning the brain with sublethal ischemia induces resistance to subsequent ordinarily lethal ischemia (ischemic tolerance). We investigated whether ischemic tolerance could be induced by preconditioning canine spinal cord. The role of heat-shock proteins (HSP) in this process was investigated. METHODS In experiment 1, the preconditioning group (n = 6) had aortic cross-clamping for 20 minutes, whereas controls (n = 6) had no cross-clamping. After 48 hours the aorta was cross-clamped for 60 minutes in both groups. Neurologic examination was performed 24 hours later and the spinal cord was studied for immunohistochemically. In experiment 2, either 48 hours after 20 minutes of clamping or after sham operation (n = 4), HSP were investigated immunohistochemically. RESULTS In experiment 1, 3 of 6 controls became paraplegic but none of the 6 preconditioning group dogs became paraplegic. The HSP appeared on sections from all 6 PC dogs and 3 control dogs that did not exhibit paraplegia. In experiment 2, HSP were present in clamped animals but could not be detected after sham operation. CONCLUSIONS Ischemic tolerance was induced by preconditioning the canine spinal cord, in which HSP are believed to be involved.
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Affiliation(s)
- K Matsuyama
- Second Department of Surgery, Fukui Medical School, Japan
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Nakamura H, Kitagawa H, Kawaguchi Y, Tsuji H. Intracortical facilitation and inhibition after transcranial magnetic stimulation in conscious humans. J Physiol 1997; 498 ( Pt 3):817-23. [PMID: 9051592 PMCID: PMC1159197 DOI: 10.1113/jphysiol.1997.sp021905] [Citation(s) in RCA: 481] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
1. Changes in excitability of the motor cortex induced by a transcranial magnetic stimulation (TMS) were examined by simultaneous recording of the evoked corticospinal volley and the compound surface electromyographic (EMG) response in the biceps brachii following paired-pulse TMS in five conscious subjects. The effects of a varying interstimulus interval (ISI) and a conditioning stimulus intensity were also investigated. 2. A submotor threshold conditioning stimulus inhibited the test responses at ISIs of 2-5 ms. A supramotor threshold conditioning stimulus inhibited the test responses at ISIs of 100-200 ms. Both of these inhibitions were prominent in late I waves. 3. There was a facilitation of the test responses at an ISI of 25 ms that was prominent in late I waves. The facilitation evoked by the supramotor threshold conditioning stimulus was more prominent than that evoked by the submotor threshold conditioning stimulus. 4. It is concluded that single TMS induced the triphasic changes of the motor cortex excitability in conscious humans that resulted in changes in EMG responses following paired TMS.
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Affiliation(s)
- H Nakamura
- Department of Orthopaedic Surgery, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Japan
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Nakamura H, Kitagawa H, Kawaguchi Y, Tsuji H. Direct and indirect activation of human corticospinal neurons by transcranial magnetic and electrical stimulation. Neurosci Lett 1996; 210:45-8. [PMID: 8762188 DOI: 10.1016/0304-3940(96)12659-8] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Corticospinal volleys and surface electromyographic (EMG) responses evoked by magnetic and electrical transcranial stimulation were recorded simultaneously in three conscious human subjects. For magnetic stimulation, the figure-of-eight coil was held on the hand motor area either with the induced current through the brain flowing in a postero-anterior direction (P-A stimulation) or in a latero-medial direction (L-M stimulation). For electrical stimulation, the anode was placed 7 cm lateral to the vertex and cathode at the vertex (anodal stimulation). The P-A stimulation that was generally used preferentially evoked I waves, whereas the L-M and anodal stimulation preferentially evoked D wave. The results suggested that the mode of activation by transcranial magnetic stimulation altered, depending on its current direction, and the difference between P-M magnetic and electrical stimulation can be explained by the context of the D and I hypothesis.
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Affiliation(s)
- H Nakamura
- Department of Orthopedic Surgery, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Japan
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