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Kawasaki S, Shigematsu H, Tanaka M, Kawaguchi M, Hayashi H, Takatani T, Suga Y, Yamamoto Y, Tanaka Y. Utility of desflurane as an anesthetic in motor-evoked potentials in spine surgery and the facilitating effect in tetanic stimulation of bilateral median nerves. J Clin Monit Comput 2024; 38:663-670. [PMID: 37917209 DOI: 10.1007/s10877-023-01096-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 10/15/2023] [Indexed: 11/04/2023]
Abstract
Although desflurane is a safe and controllable inhalation anesthetic used in spinal surgery, to our knowledge, there have been no reports of successful motor-evoked potential (MEP) recordings under general anesthesia with desflurane alone. A high desflurane concentration may reduce the risk of intraoperative awareness but can also reduce the success of MEP recording. Therefore, we aimed to evaluate the reliability of MEP monitoring and investigate whether tetanic stimulation can augment MEP amplitude under general anesthesia with high-concentration desflurane during spinal surgery. We prospectively evaluated 46 patients who were scheduled to undergo lumbar surgery at a single center between 2018 and 2020. Anesthesia was maintained with an end-tidal concentration of 4% desflurane and remifentanil. Compound muscle action potentials were recorded bilaterally from the abductor pollicis brevis, abductor hallucis, tibialis anterior, gastrocnemius, and quadriceps. For post-tetanic MEPs (p-MEPs), tetanic stimulation was applied to the median nerves (p-MEPm) and tibial nerves (p-MEPt) separately before transcranial stimulation. The average success rates for conventional MEP (c-MEP), p-MEPm, and p-MEPt were 77.9%, 80%, and 79.3%, respectively. The p-MEPm amplitudes were significantly higher than the c-MEP amplitudes in all muscles (P < 0.05), whereas the p-MEPt amplitudes were not significantly different from the c-MEP amplitudes. The MEP recording success rates for the gastrocnemius and quadriceps were inadequate. However, bilateral median nerve tetanic stimulation can effectively augment MEPs safely under general anesthesia with high-concentration desflurane in patients who undergo spinal surgery.
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Affiliation(s)
- Sachiko Kawasaki
- Department of Orthopedic Surgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan
| | - Hideki Shigematsu
- Department of Orthopedic Surgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan.
| | - Masato Tanaka
- Department of Orthopedic Surgery, Otemae Hospital, Osaka, Japan
| | | | - Hironobu Hayashi
- Department of Anesthesiology, Nara Medical University, Nara, Japan
| | - Tsunenori Takatani
- Division of Central Clinical Laboratory, Nara Medical University, Nara, Japan
| | - Yuma Suga
- Department of Orthopedic Surgery, Higashi Osaka City General Hospital, Osaka, Japan
| | - Yusuke Yamamoto
- Department of Orthopedic Surgery, Nara City Hospital, Nara, Japan
| | - Yasuhito Tanaka
- Department of Orthopedic Surgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan
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Boonzaier J, Petrov PI, Otte WM, Smirnov N, Neggers SFW, Dijkhuizen RM. Design and Evaluation of a Rodent-Specific Transcranial Magnetic Stimulation Coil: An In Silico and In Vivo Validation Study. Neuromodulation 2019; 23:324-334. [PMID: 31353780 PMCID: PMC7216963 DOI: 10.1111/ner.13025] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 06/21/2019] [Accepted: 06/26/2019] [Indexed: 12/18/2022]
Abstract
Background Rodent models are fundamental in unraveling cellular and molecular mechanisms of transcranial magnetic stimulation (TMS)‐induced effects on the brain. However, proper translation of human TMS protocols to animal models have been restricted by the lack of rodent‐specific focal TMS coils. Objective We aimed to improve TMS focalization in rodent brain with a novel small, cooled, and rodent‐specific TMS coil. Methods A rodent‐specific 25‐mm figure‐of‐eight TMS coil was developed. Stimulation focalization was simulated in silico for the rodent coil and a commercial human 50‐mm figure‐of‐eight TMS coil. Both coils were also compared in vivo by electromyography measurements of brachialis motor evoked potential (MEP) responses to TMS at different brain sites in anesthetized rats (n = 6). Focalization was determined from the coils' level of stimulation laterality. Differences in MEPs were statistically analyzed with repeated‐measures, within‐subjects, ANOVA. Results In silico simulation results deemed the human coil insufficient for unilateral stimulation of the rat motor cortex, whereas lateralized electrical field induction was projected attainable with the rodent coil. Cortical, in vivo MEP amplitude measurements from multiple points in each hemisphere, revealed unilateral activation of the contralateral brachialis muscle, in absence of ipsilateral brachialis activation, with both coils. Conclusion Computer simulations motivated the design of a smaller rodent‐specific TMS coil, but came short in explaining the capability of a larger commercial human coil to induce unilateral MEPs in vivo. Lateralized TMS, as demonstrated for both TMS coils, corroborates their use in translational rodent studies, to elucidate mechanisms of action of therapeutic TMS protocols.
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Affiliation(s)
- Julia Boonzaier
- Biomedical Magnetic Resonance Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, The Netherlands
| | - Petar I Petrov
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht and Utrecht University, Utrecht, The Netherlands
| | - Willem M Otte
- Biomedical Magnetic Resonance Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, The Netherlands.,Department of Pediatric Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht and Utrecht University, Utrecht, The Netherlands
| | | | - Sebastiaan F W Neggers
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht and Utrecht University, Utrecht, The Netherlands
| | - Rick M Dijkhuizen
- Biomedical Magnetic Resonance Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, The Netherlands
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Gazzaz M, Saini J, Pagliardini S, Tsui B, Jeffery C, El-Hakim H. Comparison of inhaled versus intravenous anesthesia for laryngoscopy and laryngeal electromyography in a rat model. J Otolaryngol Head Neck Surg 2018; 47:64. [PMID: 30342558 PMCID: PMC6196000 DOI: 10.1186/s40463-018-0312-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 10/05/2018] [Indexed: 12/26/2022] Open
Abstract
Background Propofol and remifentanil intravenous combination is one popular form of total intravenous anesthesia (TIVA) in mainstream clinical practice, but it has rarely been applied to a rat model for laryngoscopy and laryngeal electromyography (LEMG). Our objective was to establish a safe and reproducible general anesthetic protocol for laryngoscopy and endoscopic LEMG in a rat model. Our hypothesis is that TIVA allows a minimally morbid, and feasible laryngoscopy and LEMG. Methods Sprague Dawley rats were subjected to either inhalational anesthesia (IA) (isoflurane) or TIVA (propofol and remifentanil) and underwent laryngoscopy and LEMG. The primary outcome was a complete minimally interrupted rigid laryngoscopy and obtaining reproducible motor unit potentials from the posterior cricoarytenoid muscles. The secondary outcome was morbidity and mortality. Results Seventeen out of twenty-two rats underwent both TIVA and IA. Only two underwent IA only. All nineteen rats that underwent IA had a successful experiment. Seventeen rats underwent TIVA, however, only nine completed a successful experiment due to difficulty achieving a surgical plane, and respiratory events. Upon comparing the success of the two anaesthetic regimens, IA was superior to TIVA (P = 0.0008). There was no statistical difference between the amplitudes (p = 0.1985) or motor units burst duration (p = 0.82605) of both methods. Three mortalities were encountered, one of which was due to lidocaine toxicity and two were during anesthetic induction. Respiratory related morbidity was encountered in two rats, all seen with TIVA. Conclusions TIVA is not an ideal anesthetic regimen for laryngeal endoscopy and LEMG in rat models. Contrary to our hypothesis, IA did not affect the quality of the LEMG and allowed a seamless rigid endoscopy. Electronic supplementary material The online version of this article (10.1186/s40463-018-0312-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- M Gazzaz
- Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Alberta, 2C3.57 Walter MacKenzie Centre, Edmonton, AB, T6G 2R7, Canada.
| | - J Saini
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.,Women and Children Research Institute, University of Alberta, Edmonton, AB, Canada
| | - S Pagliardini
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.,Women and Children Research Institute, University of Alberta, Edmonton, AB, Canada.,Department of Physiology, University of Alberta, Edmonton, AB, Canada
| | - B Tsui
- Stanford University Pediatric Regional Anesthesia, Stanford University, Stanford, California, USA
| | - C Jeffery
- Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Alberta, 2C3.57 Walter MacKenzie Centre, Edmonton, AB, T6G 2R7, Canada
| | - H El-Hakim
- Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Alberta, 2C3.57 Walter MacKenzie Centre, Edmonton, AB, T6G 2R7, Canada
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Intraoperative Neuromonitoring and Alarm Criteria for Judging MEP Responses to Transcranial Electric Stimulation. J Clin Neurophysiol 2017; 34:12-21. [DOI: 10.1097/wnp.0000000000000339] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Chang SH, Park YG, Kim DH, Yoon SY. Monitoring of Motor and Somatosensory Evoked Potentials During Spine Surgery: Intraoperative Changes and Postoperative Outcomes. Ann Rehabil Med 2016; 40:470-80. [PMID: 27446784 PMCID: PMC4951366 DOI: 10.5535/arm.2016.40.3.470] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/02/2015] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To evaluate whether the combination of muscle motor evoked potentials (mMEPs) and somatosensory evoked potentials (SEPs) measured during spinal surgery can predict immediate and permanent postoperative motor deficits. METHODS mMEP and SEP was monitored in patients undergoing spinal surgery between November 2012 and July 2014. mMEPs were elicited by a train of transcranial electrical stimulation over the motor cortex and recorded from the upper/lower limbs. SEPs were recorded by stimulating the tibial and median nerves. RESULTS Combined mMEP/SEP recording was successfully achieved in 190 operations. In 117 of these, mMEPs and SEPs were stable and 73 showed significant changes. In 20 cases, motor deficits in the first 48 postoperative hours were observed and 6 patients manifested permanent neurological deficits. The two potentials were monitored in a number of spinal surgeries. For surgery on spinal deformities, the sensitivity and specificity of combined mMEP/SEP monitoring were 100% and 92.4%, respectively. In the case of spinal cord tumor surgeries, sensitivity was only 50% but SEP changes were observed preceding permanent motor deficits in some cases. CONCLUSION Intraoperative monitoring is a useful tool in spinal surgery. For spinal deformity surgery, combined mMEP/SEP monitoring showed high sensitivity and specificity; in spinal tumor surgery, only SEP changes predicted permanent motor deficits. Therefore, mMEP, SEP, and joint monitoring may all be appropriate and beneficial for the intraoperative monitoring of spinal surgery.
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Affiliation(s)
- Shin Hye Chang
- Department of Rehabilitation Medicine, Gangnam Severance Hospital, Seoul, Korea.; Rehabilitation Institute of Neuromuscular Disease, Yonsei University College of Medicine, Seoul, Korea
| | - Yoon Ghil Park
- Department of Rehabilitation Medicine, Gangnam Severance Hospital, Seoul, Korea.; Rehabilitation Institute of Neuromuscular Disease, Yonsei University College of Medicine, Seoul, Korea
| | - Dae Hyun Kim
- Veteran Health Service Medical Center, Seoul, Korea
| | - Seo Yeon Yoon
- Department of Rehabilitation Medicine, Gangnam Severance Hospital, Seoul, Korea.; Rehabilitation Institute of Neuromuscular Disease, Yonsei University College of Medicine, Seoul, Korea
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Direct Comparison of the Effect of Desflurane and Sevoflurane on Intraoperative Motor-evoked Potentials Monitoring. J Neurosurg Anesthesiol 2014; 26:306-12. [DOI: 10.1097/ana.0000000000000041] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Gierthmuehlen M, Wang X, Gkogkidis A, Henle C, Fischer J, Fehrenbacher T, Kohler F, Raab M, Mader I, Kuehn C, Foerster K, Haberstroh J, Freiman TM, Stieglitz T, Rickert J, Schuettler M, Ball T. Mapping of sheep sensory cortex with a novel microelectrocorticography grid. J Comp Neurol 2014; 522:3590-608. [PMID: 24851798 DOI: 10.1002/cne.23631] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 05/21/2014] [Accepted: 05/21/2014] [Indexed: 11/10/2022]
Abstract
Microelectrocorticography (µECoG) provides insights into the cortical organization with high temporal and spatial resolution desirable for better understanding of neural information processing. Here we evaluated the use of µECoG for detailed cortical recording of somatosensory evoked potentials (SEPs) in an ovine model. The approach to the cortex was planned using an MRI-based 3D model of the sheep's brain. We describe a minimally extended surgical procedure allowing placement of two different µECoG grids on the somatosensory cortex. With this small craniotomy, the frontal sinus was kept intact, thus keeping the surgical site sterile and making this approach suitable for chronic implantations. We evaluated the procedure for chronic implantation of an encapsulated µECoG recording system. During acute and chronic recordings, significant SEP responses in the triangle between the ansate, diagonal, and coronal sulcus were identified in all animals. Stimulation of the nose, upper lip, lower lip, and chin caused a somatotopic lateral-to-medial, ipsilateral response pattern. With repetitive recordings of SEPs, this somatotopic pattern was reliably recorded for up to 16 weeks. The findings of this study confirm the previously postulated ipsilateral, somatotopic organization of the sheep's sensory cortex. High gamma band activity was spatially most specific in the comparison of different frequency components of the somatosensory evoked response. This study provides a basis for further acute and chronic investigations of the sheep's sensory cortex by characterizing its exact position, its functional properties, and the surgical approach with respect to macroanatomical landmarks.
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Affiliation(s)
- Mortimer Gierthmuehlen
- Department of Neurosurgery, University Medical Center Freiburg, 79106, Freiburg, Germany
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Sloan TB, Toleikis JR, Toleikis SC, Koht A. Intraoperative neurophysiological monitoring during spine surgery with total intravenous anesthesia or balanced anesthesia with 3 % desflurane. J Clin Monit Comput 2014; 29:77-85. [DOI: 10.1007/s10877-014-9571-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Accepted: 03/12/2014] [Indexed: 10/25/2022]
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Abstract
PURPOSE Anesthesia for pediatric patients undergoing surgery where intraoperative neurophysiological monitoring (IONM) is performed is based on an understanding of the anesthetic influence on the neural pathways involved and the physiology that supplies nutrients to the neural systems. Anesthesia in pediatric patients may be different than in adults due to the specific anesthesia considerations in children, notably the propofol infusion syndrome (PRIS) and the need to monitor immature neural pathways. This review was done to determine if the anesthesia protocols used were different than those used in adults. METHODS After reviewing the implications of anesthetic action, a survey of pediatric anesthesia practitioners in 40 North American centers was conducted to determine the anesthesia protocols used in pediatric surgery with IONM and if these were specifically modified over concerns about PRIS. RESULTS Twenty-five centers responded with 35 different protocols used by practitioners. These protocols are similar to protocols used in adult patients. Although no centers specifically avoided propofol in all patients, several strategies were used to reduce the dosage, avoid its use in selected patients, or monitor for the onset of the syndrome. CONCLUSION Anesthesia for pediatric patients undergoing surgery where IONM is being performed is consistent with the practice and principles of anesthesia for adults. Although PRIS has not caused major alterations in most patients, concern has modified the practice of some anesthesiologists.
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Oria M, Chatauret N, Raguer N, Córdoba J. A new method for measuring motor evoked potentials in the awake rat: effects of anesthetics. J Neurotrauma 2008; 25:266-75. [PMID: 18352840 DOI: 10.1089/neu.2007.0393] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The goal of this investigation was to develop a method to study the neurophysiological integrity of the central motor tract using motor evoked potentials in the awake rat and assess the effects of different anesthetics in this model. Rats were implanted with six subcutaneous electrodes (pediatric myocardial pacing leads) and one cranial screw. Motor evoked potentials of the hind limb were elicited after cranial and sciatic nerve stimulation. Experiments were repeated on different days during three weeks studying the effect of three different anesthetics (propofol, ketamine/xylazine, pentobarbital) at three different doses. Stimulation of motor evoked potentials in the awake rat was well tolerated with no effects on behavior. The electrodes could be kept chronically in place without signs of infection. The repeated recordings on different days showed high reproducibility after the fourth day following implantation of the electrodes. All three anesthetics induced an increase in the latency and a decrease in the amplitude of the motor evoked potentials which were dose dependent. Propofol (up to 1 mg/kg x min(1)) affected motor evoked potentials to a lesser extent than the other anesthetics. Based upon these findings, we believe that our approach provides a new method of chronically implanting electrodes in the rat to assess the neurophysiological function of the motor tract without the need of anesthetics. This model may prove useful in the investigation of various diseases that affect the motor pathways without the confounding effects of anesthesia.
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Affiliation(s)
- Marc Oria
- Servicio de Medicina Interna-Hepatología, Hospital Vall d'Hebron, Barcelona, Spain
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Abstract
STUDY DESIGN Combined prospective and retrospective. OBJECTIVE Evaluate 2 published criteria for interpreting motor-evoked potentials (MEP) in response to repetitive transcranial electrical stimulation (rTES) during surgery. SUMMARY OF BACKGROUND DATA There is controversy regarding how to interpret MEPs elicited by rTES. Many centers warn the surgical team only if the MEP is lost entirely ("Presence-or-Absence" method). Alternatively, we monitor the stimulus energy needed to elicit a minimal evoked EMG response; significant increases in this energy reflect impending motor tract injury and serve as the basis for warning the surgical team ("Threshold-Level" method). METHODS We documented target muscle thresholds for rTES throughout each subject's surgical procedure. The time (in hours) between intraoperative threshold change and (a) complete loss of response or (b) until the end of the surgical procedure was determined. Short-term postoperative motor status was documented by either direct physical examination or by chart review. RESULTS We enrolled 903 subjects, from whom intraoperative rTES-evoked responses could be elicited in 859 subjects. Of these, 93 subjects sustained intraoperative damage to central motor pathways. Significant increases in target muscle thresholds were often noted many minutes, and sometimes hours before complete signal loss. In other cases, thresholds increased significantly without ever losing the muscle response. CONCLUSION The Threshold-Level method is highly sensitive and specific to deterioration in central motor function, and provides early warning of such an event. Conversely, in some cases the Presence-or-Absence method may fail to detect episodes of partial loss, and in other cases typically introduces a delay between the times when motor dysfunction begins to occur and when the response is lost (at which time an alarm is triggered). We conclude that use of the Presence-or-Absence alarm criteria for interpreting MEPs during surgery is often incompatible with the requirement for accurate and early warning of impending injury to central motor pathways, and should be avoided.
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Sloan TB, Jäntti V. Anesthetic effects on evoked potentials. INTRAOPERATIVE MONITORING OF NEURAL FUNCTION 2008. [DOI: 10.1016/s1567-4231(07)08005-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Oria M, Raguer N, Chatauret N, Bartolí R, Odena G, Planas R, Córdoba J. Functional abnormalities of the motor tract in the rat after portocaval anastomosis and after carbon tetrachloride induction of cirrhosis. Metab Brain Dis 2006; 21:297-308. [PMID: 17136622 DOI: 10.1007/s11011-006-9036-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2005] [Accepted: 06/07/2006] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Hepatic encephalopathy is a neurologic syndrome secondary to liver failure that causes cognitive and motor abnormalities. Impairment in the function of the first neuron of the motor tract (corticospinal tract) has been demonstrated in patients with cirrhosis and minimal hepatic encephalopathy. AIM Investigate the function of the first neuron of the motor tract in experimental models of minimal hepatic encephalopathy. MATERIAL AND METHODS Rats with portocaval anastomosis (n = 8) and rats with carbon tetrachloride induced cirrhosis (n = 11) underwent neurophysiological recording under light anesthesia with propofol. Motor evoked potentials were elicited applying a transcranial electric pulse and were recorded in the tibialis anterior muscle. The effect of the dose of anesthesia was assessed in a group of normal rats (n = 10). RESULTS Rats with portocaval anastomosis exhibited a decrease in motor evoked potentials amplitude following surgery (67 +/- 11 to 41 +/- 16%, P < 0.001). Cirrhotic rats exhibited an increase in motor evoked potentials latency after the appearance of ascites (4.65 +/- 0.43 to 5.15 +/- 0.67 ms., P = 0.04). Increasing doses of propofol produced a decrease in the amplitude and an increase in the latency of motor evoked potentials. CONCLUSION It is possible to reproduce functional abnormalities of the central motor tract in rats with portocaval anastomosis and carbon tetrachloride induced cirrhosis. The development of motor abnormalities in experimental models of minimal hepatic encephalopathy offers the possibility to investigate the mechanisms involved in the pathogenesis of hepatic encephalopathy and test therapeutic strategies.
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Affiliation(s)
- Marc Oria
- Liver Unit, Hospital Universitari Vall d'Hebron, Department of Medicine, Universitat Autònoma de Barcelona, Passeig Vall d'Hebron 119-129, 08035, Barcelona, Spain
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Devlin VJ, Anderson PA, Schwartz DM, Vaughan R. Intraoperative neurophysiologic monitoring: focus on cervical myelopathy and related issues. Spine J 2006; 6:212S-224S. [PMID: 17097541 DOI: 10.1016/j.spinee.2006.04.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Accepted: 04/07/2006] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT The use of neurophysiologic monitoring during surgical procedures for cervical spondylotic myelopathy (CSM) is controversial. PURPOSE The aim of this article is to review the literature regarding various monitoring techniques as applied to the patient with CSM. STUDY DESIGN/METHODS A systematic literature review. CONCLUSIONS Neurophysiologic monitoring is a diagnostic tool for assessment of neurologic function during cervical spine surgery. Recording of somatosensory evoked potentials (SSEPs), transcranial electrical motor evoked potentials (tceMEPs), and electromyograms (EMGs) may be useful as these monitoring modalities provide complementary information.
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Affiliation(s)
- Vincent J Devlin
- Geisinger Medical Center, Department of Orthopedic Surgery, M.C. 21-30, 100 North Academy Avenue, Danville, PA 17822, USA.
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Imani F, Jafarian A, Hassani V, Khan ZH. Propofol–alfentanil vs propofol–remifentanil for posterior spinal fusion including wake-up test. Br J Anaesth 2006; 96:583-6. [PMID: 16567343 DOI: 10.1093/bja/ael075] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Wake-up test can be used during posterior spinal fusion (PSF) to ensure that spinal function remains intact. This study aims at assessing the characteristics of the wake-up test during propofol-alfentanil (PA) vs propofol-remifentanil (PR) infusions for PSF surgery. METHODS Sixty patients with scoliosis and candidates for PSF surgery were randomly allocated in either alfentanil (PA) or remifentanil (PR) group. After an i.v. bolus of alfentanil 30 microg kg(-1) in the PA group or remifentanil 1 microg kg(-1) in the PR group, anaesthesia was induced with thiopental and atracurium. During maintenance, opioid infusion consisted of alfentanil 1 microg kg(-1) min(-1) or remifentanil 0.2 microg kg(-1) min(-1), in the PA group and the PR group, respectively. All patients received propofol 50 microg kg(-1) min(-1). Atracurium was given to maintain the required surgical relaxation. At the surgeon's request, all infusions were discontinued. Patients were asked to move their hands and feet. Time from anaesthetic discontinuation to spontaneous ventilation (T(1)), and from then until movement of the hands and feet (T(2)), and its quality were recorded. RESULTS The average T(1) and T(2) were significantly shorter in the PR group [3.6 (2.5) and 4.1 (2) min] than the PA group [6.1 (4) and 7.5 (4.5) min]. Quality of wake-up test, however, did not show significant difference between the two groups studied. CONCLUSION Wake-up test can be conducted faster with remifentanil compared with alfentanil infusion during PSF surgery.
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Affiliation(s)
- F Imani
- Department of Anaesthesiology, Rasool-Akram Hospital, School of Medicine, Iran University of Medical Sciences Tehran, Iran.
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Thuet ED, Padberg AM, Raynor BL, Bridwell KH, Riew KD, Taylor BA, Lenke LG. Increased risk of postoperative neurologic deficit for spinal surgery patients with unobtainable intraoperative evoked potential data. Spine (Phila Pa 1976) 2005; 30:2094-103. [PMID: 16166902 DOI: 10.1097/01.brs.0000178845.61747.6a] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN This was a retrospective study of 4,310 patients undergoing spinal surgery between 1994 and 2003. OBJECTIVES To examine the incidence and potential causality of unobtainable somatosensory evoked potential (SSEP) and neurogenic mixed evoked potential (NMEP) data for a population of spinal surgery patients. SUMMARY OF BACKGROUND DATA Patients with absent or unobtainable evoked potential data may increase the risk of undetected neurologic injury. To date, a comprehensive review of this patient population has not been reported. METHODS A total of 4,310 consecutive orthopedic spinal surgeries at one institution from January 1994 through December 2003 were reviewed. Cases lacking sufficient monitoring data, despite functional neural integrity (ambulators, intact sensation), were identified. Diagnoses were divided into six general categories. The association between absent evoked potential data and associated neurologic and/or medical pathology was evaluated. RESULTS A total of 59 of 4,310 cases (1.37%) had absent SSEP and/or NMEP intraoperative data despite functional neural integrity (44 ambulators/15 nonambulators)" 5.08% of study patients awoke with increased neurologic deficit (3 of 59), 2 global deficits, and 1 nerve root deficit. The incidence of postoperative neurologic deficit in the entire surgical population was 0.77% (33 of 4,310), 8 global (0.19%), and 25 nerve root deficits (0.058%). A Fisher's exact test demonstrated a statistically significant difference between the incidence in these two populations (P = 0.0121) and the incidence of global paraplegic deficits (P = 0.0075). CONCLUSION Patients with unobtainable data pose a much higher risk (P = 0.0121) for postoperative neurologic deficits. Multiple Stagnara wake-up tests are strongly recommended when evoked potential data cannot be obtained.
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Affiliation(s)
- Earl D Thuet
- Washington University Medical Center, Department of Orthopaedic Surgery, BJC Health Systems, St. Louis, MO, USA
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Jou IM, Chern TC, Chen TY, Tsai YC. Effects of desflurane on spinal somatosensory-evoked potentials and conductive spinal cord evoked potential. Spine (Phila Pa 1976) 2003; 28:1845-50. [PMID: 12923473 DOI: 10.1097/01.brs.0000083459.54468.88] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Spinal somatosensory-evoked potential (interspinous-space-recorded evoked potentials after peripheral nerve or dermatomal stimulation) and conductive spinal cord evoked potential (interspinous-space-recorded evoked potentials after spinal cord stimulation) were analyzed in rats under different concentrations of the anesthetic desflurane. OBJECTIVES To investigate and compare the effects of a new volatile anesthetic, desflurane, on the common intraoperative neuromonitoring models. SUMMARY OF BACKGROUND DATA Intraoperative evoked potentials are sensitive to most anesthetics. Interpretation of the data becomes complicated because of a suppression effect caused by the anesthesia. Desflurane has become a valuable anesthetic in neurosurgery because of its pharmacokinetic advantages. METHODS Fifteen rats were placed under general anesthesia, and vital signs were closely monitored. Needle recording electrodes were placed stereotactically into the thoracolumbar interspinous ligament; dermatomal somatosensory-evoked potential by L5 dermatome, mixed-nerve somatosensory-evoked potential by sciatic nerve stimulation, and spinal cord evoked potential of the same recording electrodes elicited by C2-C3 interspinous stimulation were obtained. The effects of desflurane were examined at end-tidal concentrations of 6% (1.05 minimal alveolar concentration), 9% (1.57 minimal alveolar concentration), and 12% (2.10 minimal alveolar concentration). RESULTS Amplitude decreased and latency was delayed in all three kinds of potentials, and the more so with higher concentrations. Comparing 9% with 6% desflurane, the amplitude in dermatomal somatosensory-evoked potential, mixed-nerve somatosensory-evoked potential, and spinal cord evoked potential decreased to 84.3%, 88.9%, and 70.8%, respectively, values with no statistically significant difference. However, at 12%, again compared with 6%, the amplitude decreased further to 64.4%, 70.3%, 41.8%, respectively; mixed-nerve somatosensory-evoked potential and dermatomal somatosensory-evoked potential were significantly more preserved than spinal cord evoked potential (P = 0.04). CONCLUSIONS The concentration of desflurane alters the amplitude of somatosensory-evoked potential and spinal cord evoked potential, and, to a lesser degree, delays the latency; spinal cord evoked potential is more liable to be suppressed than somatosensory-evoked potential. The dose-dependent suppression effect on amplitude should be considered when interpreting changes during surgery. Furthermore, the potential benefit of somatosensory-evoked potential elicited by direct major nerve stimulation should be considered because of its large amplitude and higher resistance, even with a greater concentration of volatile anesthetics.
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Affiliation(s)
- I-Ming Jou
- Department of Orthopedics, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
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Aglio LS, Romero R, Desai S, Ramirez M, Gonzalez AA, Gugino LD. The use of transcranial magnetic stimulation for monitoring descending spinal cord motor function. CLINICAL EEG (ELECTROENCEPHALOGRAPHY) 2002; 33:30-41. [PMID: 11795209 DOI: 10.1177/155005940203300106] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This report describes our initial clinical experience using transcranial magnetic stimulation for monitoring spinal cord motor function during surgical procedures. Motor evoked potentials were elicited using a cap shaped coil placed on the scalp of 27 patients while recording peripheral motor responses (compound muscle action potentials--CMAPs) from the upper (N = 1) or lower limbs (N = 26). Wherever possible, cortical somatosensory responses (SEPs) were also monitored by electrically stimulating the left and right posterior tibial nerve (N = 25) or the median nerve (N = 1). The judicious choice of anesthetic regimens resulted in successfully obtaining motor evoked responses (MEPs) in 21 of 27 patients and SEPs in 26 of 27 patients. Single pulse TMS resulted in peripheral muscle responses having large variability, whereas, the variability of SEPs was much less. Criteria based on response variability for assessing clinically significant changes in both MEPs and SEPs resulted in two false negative predictions for SEPs and none for MEPs when evaluating postoperative motor function. We recommend monitoring both sensory and motor pathways during procedures where placing the spinal cord at risk of damage.
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Affiliation(s)
- Linda S Aglio
- Department of Anesthesia, Harvard Medical School, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
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Pelosi L, Stevenson M, Hobbs GJ, Jardine A, Webb JK. Intraoperative motor evoked potentials to transcranial electrical stimulation during two anaesthetic regimens. Clin Neurophysiol 2001; 112:1076-87. [PMID: 11377268 DOI: 10.1016/s1388-2457(01)00529-6] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVES To study motor evoked potentials (MEPs) to multi-pulse transcranial electrical stimulation (MP-TES) during orthopaedic spinal surgery under different anaesthetic regimens. METHODS MEPs to MP-TES were recorded from tibialis anterior and abductor hallucis bilaterally in 50 operations. Anaesthesia was maintained with propofol and nitrous oxide in 29 operations and isoflurane (0.78+/-0.17% end-tidal) and nitrous oxide in 23 (two patients received both regimens). Analgesia was provided with fentanyl or remifentanil. RESULTS Motor stimulation caused neither EEG changes nor seizures. MEPs were obtained in 97% of patients during propofol anaesthesia. The median amplitude and coefficient of variation (CV) at baseline (across all muscles) were 198 microV and 22%, respectively. Amplitudes throughout the operation paralleled the degree of neuromuscular block and were reduced after fentanyl bolus, isoflurane or morphine. Loss of MEPs or persistent amplitude decrements were associated with neurological complications in one patient and severe blood loss in another two patients. MEPs were obtainable in 61% of patients during isoflurane anaesthesia and became inconsistent for end-tidal concentrations >0.87+/-0.08%. Amplitudes were smaller (85 microV) and baseline variability higher (coefficient of variation 29%) than in the propofol group. The decrease in the number of recordings was greater for isoflurane than propofol when the number of pulses/train decreased from 4 to 2. CONCLUSIONS Muscle MEPs to MP-TES are a safe, sensitive and reliable method for monitoring motor pathways during propofol/nitrous oxide and fentanyl or remifentanil anaesthesia. MEPs are also obtainable in the majority of patients during isoflurane/nitrous oxide anaesthesia, but quantitative monitoring is not always possible with this regimen.
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Affiliation(s)
- L Pelosi
- Department of Clinical Neurophysiology, University Hospital, Queen's Medical Centre, NG7 2UH, Nottingham, UK
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Toleikis JR, Skelly JP, Carlvin AO, Burkus JK. Spinally elicited peripheral nerve responses are sensory rather than motor. Clin Neurophysiol 2000; 111:736-42. [PMID: 10727925 DOI: 10.1016/s1388-2457(99)00317-x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVES Spinally elicited peripheral nerve responses, commonly called neurogenic motor evoked potentials (NMEPs), are widely used to monitor spinal cord motor function during surgery. However, numerous evidence suggests that these responses are primarily sensory rather than motor. The collision technique was utilized to address this issue. METHODS Collision studies were performed in 7 patients during surgery. An ascending volley of sensory (AS) and motor activity (AM) was elicited by posterior tibial nerve stimulation at the popliteal fossa. After a short time delay, high cervical spinal stimulation produced a descending volley of sensory (DS) and motor (DM) activity. The AM volley ascended only to the anterior horn cells whereas the AS and DS volleys collided in the spinal cord. The inter-stimulus delays were varied so as to affect the degree of spinal cord collision. The DS and DM activity which remained after collision was recorded from the posterior tibial nerves at the ankle. RESULTS Inter-stimulus delays of 18 ms or less resulted in no apparent peripheral descending volleys. These findings were consistent for all the patients studied. CONCLUSIONS Spinally elicited peripheral nerve responses are primarily sensory rather than motor and are mediated by the same neural pathways as SEPs.
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Affiliation(s)
- J R Toleikis
- Hughston Sports Medicine Hospital, Columbus, USA.
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22
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Andel H, Bayer GS, Ciovica R, Monsivais J, Basco M, Zimpfer M, Turkof E. Depressive effect of isoflurane on motor evoked potentials in the Nubian goat. Can J Anaesth 2000; 47:81-6. [PMID: 10626726 DOI: 10.1007/bf03020739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
PURPOSE To determine the effect of isoflurane on motor evoked potentials (MEP) in a new animal model designed to verify the applicability of MEPs in brachial plexus surgery, and to compare the results with previous reports in other animals. METHODS In seven goats, anesthesia was induced with 3 mg x kg(-1) ketamine i.v. and maintained with nitrous oxide 40% in oxygen and 2 microg x kg(-1) x hr(-1) fentanyl i.v.. The MEP were performed with two subcutaneous needle electrodes placed over the occiput (cathode) and the nasion (anode), with their plugs connected to the power output of a Digitimer D 180 electrical stimulator, connected to the trigger input of an electromyograph (model 8400, Cadwell Laboratories, Inc., Kennwick, Washington). Activation of the Digitimer caused central stimulation of the motor cortex, evoking baseline compound muscle action potentials (CMAPs) which were recorded from the left triceps muscle. Subsequently, isoflurane 2% was administered together with repeated central stimulation at 30 sec intervals. RESULTS Onset of I- (indirect) waves increased from median 15,8 msec to median 26,8 msec P = 0,018 (latency increase ranged from: 9 to 11.5 msec), while peak-to-peak amplitudes decreased and subsequently disappeared. D- (direct) waves showed no latency increase, and finally disappeared as well. After disappearance of CMAPs, isoflurane administration was stopped and MEP repeated. The CMAPs reappeared (range: 210-360 sec) and regained initial peak-to-peak amplitudes and latencies. CONCLUSION These animal studies suggest that isoflurane should not be used during the recording of MEPs.
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Affiliation(s)
- H Andel
- Department of Anesthesiology and Intensive Care, University of Vienna, Austria, Europe
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van Dongen EP, ter Beek HT, Schepens MA, Morshuis WJ, Langemeijer HJ, de Boer A, Boezeman EH. Within-Patient Variability of Myogenic Motor-Evoked Potentials to Multipulse Transcranial Electrical Stimulation During Two Levels of Partial Neuromuscular Blockade in Aortic Surgery. Anesth Analg 1999. [DOI: 10.1213/00000539-199901000-00005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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van Dongen EP, ter Beek HT, Schepens MA, Morshuis WJ, Langemeijer HJ, de Boer A, Boezeman EH. Within-patient variability of myogenic motor-evoked potentials to multipulse transcranial electrical stimulation during two levels of partial neuromuscular blockade in aortic surgery. Anesth Analg 1999; 88:22-7. [PMID: 9895060 DOI: 10.1097/00000539-199901000-00005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED Intraoperative recording of myogenic motor responses evoked by transcranial electrical stimulation (tcMEPs) is a method of assessing the integrity of the motor pathways during aortic surgery. To identify conditions for optimal spinal cord monitoring, we investigated the effects of manipulating the level of neuromuscular blockade (T1 response of the train-of-four (TOF) stimulation 5%-15% versus T1 response 45%-55% of baseline), as well as the number of transcranial pulses (two versus six stimuli) on the within-patient variability and amplitude of tcMEPs. Ten patients (30-76 yr) scheduled to undergo surgery on the thoracic and thoracoabdominal aorta were studied. After achieving a stable anesthetic state and before surgery, 10 tcMEPs were recorded from the right extensor digitorum communis muscle and the right tibialis anterior muscle in response to two-pulse and six-pulse transcranial electrical stimulation with an interstimulus interval of 2 ms during two levels of neuromuscular blockade. The right thenar eminence was used for recording the level of relaxation. The tcMEP amplitude using the six-pulse paradigm was larger (P < 0.01; leg and arm) compared with the amplitude evoked by two-pulse stimulation during both levels of relaxation. The within-patient variability, expressed as median coefficient of variation, was less when six-pulse stimulation was used. At a T1 response of 45%-55% of baseline, larger, less variable tcMEPs were recorded than at a T1 response of 5%-15%. Our results suggest that the best quality of tcMEP signals (tibialis anterior muscle) is obtained when the six-pulse paradigm is used with a stable level of muscle relaxation (the first twitch of the TOF-thenar eminence-at 45%-55% of baseline). IMPLICATIONS This study shows that six-pulse (rather than two-pulse) transcranial electrical stimulation during a stable anesthetic state and a stable neuromuscular blockade aimed at 45%-55% (rather than 5%-15%) of baseline provides reliable and recordable muscle responses sufficiently robust for spinal cord monitoring in aortic surgery.
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Affiliation(s)
- E P van Dongen
- Department of Anesthesiology and Intensive Care, St. Antonius Hospital, Neiuwegein, The Netherlands
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Péréon Y, Nguyen The Tich S. Le monitorage des potentiels évoqués mixtes neurogènes au cours de la chirurgie du rachis: une bonne solution? Neurophysiol Clin 1998. [DOI: 10.1016/s0987-7053(98)80003-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Péréon Y, Bernard JM, Fayet G, Delécrin J, Passuti N, Guihéneuc P. Usefulness of neurogenic motor evoked potentials for spinal cord monitoring: findings in 112 consecutive patients undergoing surgery for spinal deformity. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1998; 108:17-23. [PMID: 9474058 DOI: 10.1016/s0168-5597(97)00056-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Neurogenic motor evoked potential (NMEP) monitoring, which basically represents a monitoring of both motor and somatosensory tracts, has been proposed as a warning system in preventing neural damage during spinal surgery. The aim of this study was to report our clinical experience in 112 consecutive patients undergoing surgery for spinal deformity, and to emphasize the interest of NMEP monitoring. NMEPs were elicited in each patient by electrical stimulation of the spinal cord via needle electrodes placed by the surgeon in the rostral part of the surgical field, and recorded from the right and left sciatic nerves. Concomitantly, somatosensory evoked potentials (SSEPs) were obtained using a standard method. No false-negative cases of intra-operative spinal cord damage were reported. In 3 patients, both NMEPs and SSEPs suddenly disappeared during specific surgical manipulations of the vertebral implants. In these patients, the level of the lesion was easily recognized by moving the stimulating electrodes of NMEPs along the spinal cord, allowing the surgeon to perform laminectomy at the appropriate vertebral level. Spinal cord decompression was a success in two patients, the last unfortunately being paraplegic. Two additional patients exhibited transient reduction in NMEP amplitude at the insertion of a rod while SSEPs did not change significantly. In these two cases, the surgeon modified his procedure according to the NMEP changes, possibly avoiding a neurological complication. Each time evoked potentials were significantly altered, significant information was more rapidly acquired with NMEPs than with SSEPs. These results suggest that NMEPs can be used as primary choice for detecting impeding lesion of the spinal cord during critical steps of spinal surgery.
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Affiliation(s)
- Y Péréon
- Laboratoire d'Explorations Fonctionnelles, University Hospital, Hôtel-Dieu, Nantes, France.
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Pérez-Espejo M, Poza y Poza M, Haghighi S, Oró J. Traumatismos medulares experimentales: Revisión de la literatura y descripción de un modelo mediante compresión mantenida en la rata. Neurocirugia (Astur) 1996. [DOI: 10.1016/s1130-1473(96)71077-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Kong K, Ukachoke C, McGuire G, Wong D, Ashby P. The excitability of human corticospinal neurons is depressed by thiopental. Can J Neurol Sci 1995; 22:218-22. [PMID: 8529174 DOI: 10.1017/s0317167100039871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND We tested the effect of thiopental on the excitability of the corticospinal-motoneuron axis in normal human subjects. METHODS Magnetic stimulation was used to excite the neurons in the motor cortex which give rise to the fast conducting corticospinal pathway. The characteristics of the composite excitatory post-synaptic potentials (EPSPs) produced in individual spinal motoneurons by cortical stimulation were derived from changes in the firing probability of voluntarily activated motor units of the first dorsal interosseous muscle. RESULTS In 5 normal subjects, we found that thiopental, in incremental doses sufficient to sustain drowsiness (total dose 75 to 175 mg), significantly reduced the amplitude of these composite EPSPs. CONCLUSIONS Thiopental reduced the facilitation of motoneurons from the cortex most likely by depressing cortical neurons.
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Affiliation(s)
- K Kong
- Division of Neurology, University of Toronto, Ontario, Canada
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Kalkman CJ, Drummond JC, Patel PM, Sano T, Chesnut RM. Effects of droperidol, pentobarbital, and ketamine on myogenic transcranial magnetic motor-evoked responses in humans. Neurosurgery 1994; 35:1066-71. [PMID: 7885550 DOI: 10.1227/00006123-199412000-00008] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Myogenic motor-evoked responses to transcranial magnetic stimulation of the motor cortex (tcmag-MERs) may become clinically useful for the noninvasive assessment of motor pathway conduction during surgery. However, application is hindered because most anesthetic regimens result in severe depression of tcmag-MER amplitudes. As part of our systematic attempts to identify anesthetic agents and supplements suitable for use during tcmag-MER recording, we studied the effect of bolus doses of pentobarbital (1.5 mg/kg), droperidol (0.07 mg/kg), or ketamine (1 mg/kg), administered intravenously, on compound muscle action potentials to transcranial magnetic stimulation in five healthy volunteers. The doses were chosen to be comparable with doses that might be suitable for supplementation of a nitrous oxide/opioid anesthetic technique. Droperidol administration resulted in sustained amplitude depression of both tibialis and adductor pollicis tc-MERs to 30 +/- 9% and 39 +/- 14% of baseline (P < 0.01). Tcmag-MER amplitude changes after pentobarbital were variable, ranging from no change to substantial amplitude depression (to 20% of baseline) in two subjects. In contrast, ketamine administration did not result in significant amplitude depression. In three subjects, tibialis anterior amplitude increased to 150 to 220% of control values in the first 10 minutes after ketamine. Onset latency was unchanged after any drug. These data indicate that tcmag-MERs are moderately depressed after droperidol and pentobarbital but well preserved after ketamine. Ketamine may be a more suitable supplement to opioid/nitrous oxide anesthesia than droperidol or pentobarbital.
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Affiliation(s)
- C J Kalkman
- Department of Anesthesiology, University of California, San Diego
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30
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Effects of Droperidol, Pentobarbital, and Ketamine on Myogenic Transcranial Magnetic Motor-evoked Responses in Humans. Neurosurgery 1994. [DOI: 10.1097/00006123-199412000-00008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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31
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Stinson LW, Murray MJ, Jones KA, Assef SJ, Burke MJ, Behrens TL, Lennon RL. A computer-controlled, closed-loop infusion system for infusing muscle relaxants: its use during motor-evoked potential monitoring. J Cardiothorac Vasc Anesth 1994; 8:40-4. [PMID: 7909456 DOI: 10.1016/1053-0770(94)90010-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A microcomputer-controlled closed-loop infusion system (MCCLIS) has been developed that provides stable intraoperative levels of partial neuromuscular blockade. Complete neuromuscular blockade interferes with intraoperative motor-evoked potential (MEP) monitoring used for patients undergoing surgical procedures that place them at risk for spinal cord ischemia. Nine patients were studied during which the MCCLIS maintained stable levels of partial neuromuscular blockade and allowed transcranial magnetic motor-evoked potential (TcM-MEP) monitoring during thoracoabdominal aortic aneurysmectomy. The use of TcM-MEP for monitoring intraoperative spinal cord function was balanced against surgical considerations for muscle relaxation with 80% to 90% neuromuscular blockade fulfilling each requirement. Intraoperative adjustment of partial neuromuscular blockade to facilitate TcM-MEP monitoring was also possible with the MCCLIS. The MCCLIS should allow for further investigation into the sensitivity, specificity, and predictability of TcM-MEP monitoring for any patient at risk for intraoperative spinal cord ischemia including those undergoing thoracoabdominal aortic aneurysmectomy.
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Affiliation(s)
- L W Stinson
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905
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Keller BP, Haghighi SS, Oro JJ, Eggers GW. The effects of propofol anesthesia on transcortical electric evoked potentials in the rat. Neurosurgery 1992; 30:557-60. [PMID: 1374852 DOI: 10.1227/00006123-199204000-00014] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The effects of halogenated anesthetic agents on somatosensory and motor evoked potentials (MEP) have been documented previously. Intravenous anesthetic propofol has not yet been used during MEP monitoring. This study investigates the effects of propofol on transcortical MEP in rats during bolus, infusion, and recovery conditions. After baseline MEP recordings, animals received a hetastarch bolus, followed by a propofol (10 mg/kg) bolus dose. A propofol infusion (10 mg/kg/h) and a hetastarch infusion were then begun. MEP recordings were obtained after the propofol bolus, during the infusion, and after a 30-minute recovery phase. Blood pressure readings remained stable. MEP onset latency increased, and amplitude decreased. Response duration diminished. All values returned towards the baseline during recovery. Our results show that the effects of propofol on MEPs are similar to its effects on somatosensory evoked potentials. Propofol seems to be a reasonable agent for use during intraoperative MEP monitoring and should be further investigated for use during spinal cord monitoring in humans.
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Affiliation(s)
- B P Keller
- Department of Anesthesiology, University of Missouri-Columbia
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The Effects of Propofol Anesthesia on Transcortical Electric Evoked Potentials in the Rat. Neurosurgery 1992. [DOI: 10.1097/00006123-199204000-00014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Stone JL, Ghaly RF, Levy WJ, Kartha R, Krinsky L, Roccaforte P. A comparative analysis of enflurane anesthesia on primate motor and somatosensory evoked potentials. ACTA ACUST UNITED AC 1992; 84:180-7. [PMID: 1372233 DOI: 10.1016/0168-5597(92)90023-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The effect of increasing enflurane concentration on magnetic-induced myogenic cranial (Cr) and peripheral (Pr) motor evoked potentials (MEPs), and electrically induced median (MN) and posterior tibial (PTN) somatosensory evoked potentials (SEPs) was studied in 10 monkeys. MEP, recorded from abductor pollicis brevis and abductor hallucis muscles, and SEP (short- and long-latency scalp recorded potentials) variables were examined at 0.25, 0.5, 0.75, 1.0 MAC enflurane concentrations. Cr-MEPs progressively attenuated (P less than 0.01) with 0.25 MAC and were abolished (greater than or equal to 0.75 MAC) by graded enflurane concentration. Stimulation threshold for Cr-MEP was progressively elevated (P less than 0.01), and eventually reliable responses were lost (greater than or equal to 0.75 MAC). Marked scalp zone reduction to obtain Cr-MEP responses was noted with increasing enflurane concentration. Pr-MEPs and most SEP peaks maintained good replicability but showed significant amplitude reduction (P less than 0.01). MEP and SEP latency values were not significantly delayed as long as the wave form remained identifiable. We conclude that enflurane has a differential influence on Cr-MEPs and SEPs. Administration of enflurane should be discouraged while monitoring myogenic Cr-MEPs since even a subanesthetic concentration is profoundly detrimental.
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Affiliation(s)
- J L Stone
- Department of Neurological Surgery, Cook County Hospital, Chicago, IL 60612
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Influence of Some Anesthetic Agents on Muscle Responses to Transcranial Magnetic Cortex Stimulation. Neurosurgery 1992. [DOI: 10.1097/00006123-199201000-00015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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