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Costa P, Borio A, Marmolino S, Turco C, Serpella D, Della Cerra E, Cipriano E, Ferlisi S. The role of intraoperative extensor digitorum brevis muscle MEPs in spinal surgery. 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 2023; 32:3360-3369. [PMID: 37336795 DOI: 10.1007/s00586-023-07811-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 04/11/2023] [Accepted: 06/03/2023] [Indexed: 06/21/2023]
Abstract
PURPOSE Intraoperative muscle motor evoked potentials (m-MEPs) are widely used in spinal surgery with the aim of identifying a damage to spinal cord at a reversible stage. Generally, lower limb m-MEPs are recorded from abductor hallucis [AH] and the tibialis anterior [TA]. The purpose of this work is to study an unselected population by recording the m-MEPs from TA, AH and extensor digitorum brevis (EDB), with the aim of identifying the most adjustable and stable muscles responses intraoperatively. METHODS Transcranially electrically induced m-MEPs were intraoperative recorded in a total of 107 surgical procedures. m-MEPs were recorded by a needle electrode placed in the muscle from TA, AH and EDB muscles in the lower extremities. RESULTS Overall monitorability (i.e., at least 1 Lower Limb m-MEP recordable) was 100/107 (93.5%). In the remaining 100 surgeries in 3 cases, the only muscle that could be recorded at baseline was one AH, and in other 2 the EDB. Persistence (i.e., the recordability of m-MEP from baseline to the end of surgery) was 88.7% for TA, 89.8% for AH and 93.8% for EDB. CONCLUSION In our series, EDB m-MEPs have demonstrated a recordability superior to TA and a stability similar to AH. The explanations may be different and range from changes in the excitability of the cortical motor neuron to the different sensitivity to ischemia of the spinal motor neuron. EDB can be used alternatively or can be added to TA and AH as a target muscle of the lower limb in spinal surgery.
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Affiliation(s)
- Paolo Costa
- Department of Neurosciences and Mental Health, Section of Clinical Neurophysiology, Città della Salute e della Scienza, Turin, EU, Italy.
| | - Alessandro Borio
- Department of Neurosciences and Mental Health, Section of Clinical Neurophysiology, Città della Salute e della Scienza, Turin, EU, Italy
| | - Sonia Marmolino
- Department of Neurosciences and Mental Health, Section of Clinical Neurophysiology, Città della Salute e della Scienza, Turin, EU, Italy
| | - Cristina Turco
- Department of Neurosciences and Mental Health, Section of Clinical Neurophysiology, Città della Salute e della Scienza, Turin, EU, Italy
| | - Domenico Serpella
- Department of Neurosciences and Mental Health, Section of Clinical Neurophysiology, Città della Salute e della Scienza, Turin, EU, Italy
| | - Elena Della Cerra
- Department of Neurosciences and Mental Health, Section of Clinical Neurophysiology, Città della Salute e della Scienza, Turin, EU, Italy
| | - Elia Cipriano
- Department of Translational Medicine, Section of Neurology, University of Piemonte Orientale, Novara, Italy
| | - Salvatore Ferlisi
- Department of Biomedicine, Neurosciences and Advanced Diagnostic (BiND), University of Palermo, Palermo, Italy
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Deletis V, Tellez MJ, Ulkatan S, Urriza J. Review on MEP monitoring disregarding D-wave references. Clin Neurophysiol 2023; 152:112-113. [PMID: 37316387 DOI: 10.1016/j.clinph.2023.04.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 04/15/2023] [Indexed: 06/16/2023]
Affiliation(s)
| | | | - Sedat Ulkatan
- Mount Sinai West Hospital, New York, NY, United States
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Dulfer SE, Gadella MC, Sahinovic MM, Lange F, Absalom AR, Groen RJM, Szelényi A, Drost G. Reply to "Review on MEP monitoring disregarding D-wave references". Clin Neurophysiol 2023; 152:114. [PMID: 37302916 DOI: 10.1016/j.clinph.2023.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 05/08/2023] [Indexed: 06/13/2023]
Affiliation(s)
- S E Dulfer
- Department of Neurosurgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
| | - M C Gadella
- Department of Neurosurgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - M M Sahinovic
- Department of Anesthesiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - F Lange
- Department of Neurosurgery, Hospital of the Ludwig Maximilians University Munich (LMU), Munich, Germany
| | - A R Absalom
- Department of Anesthesiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - R J M Groen
- Department of Neurosurgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - A Szelényi
- Department of Neurosurgery, Hospital of the Ludwig Maximilians University Munich (LMU), Munich, Germany
| | - G Drost
- Department of Neurosurgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Dulfer SE, Gadella MC, Sahinovic MM, Lange F, Absalom AR, Groen RJM, Szelényi A, Drost G. Stimulation parameters for motor evoked potentials during intraoperative spinal cord monitoring. A systematic review. Clin Neurophysiol 2023; 149:70-80. [PMID: 36924672 DOI: 10.1016/j.clinph.2023.02.170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 01/10/2023] [Accepted: 02/08/2023] [Indexed: 03/06/2023]
Abstract
OBJECTIVE The aim of this systematic review was to find the optimal stimulation parameters for muscle recorded transcranial electrical stimulation motor evoked potential (mTc-MEP) and D-wave monitoring during spinal cord monitoring. METHODS A PRISMA systematic search in Medline and EMBASE and a QUADAS-2 quality evaluation was performed to identify studies that compared stimulation parameters consisting of stimulation location, number of pulses, pulse duration, interstimulus interval, double train (DTS) or recurrent train stimulation (RTS) and intertrain interval (ITI) for performing mTc-MEP and D-wave monitoring. Only studies that used total intravenous anaesthesia (TIVA) were included. RESULTS Ten studies that compared stimulation parameters for performing mTc-MEP monitoring (stimulation location n = 4, number of pulses n = 2, pulse duration n = 1, interstimulus interval n = 4, DTS n = 1, RTS n = 2, ITI n = 2) were included. No studies compared stimulation parameters (stimulation location and pulse duration) for performing D-wave monitoring. CONCLUSIONS Few studies examined the optimal stimulation parameters for monitoring mTc-MEPs and no studies were included for D-wave monitoring. There is a need for prospective research to investigate the optimal stimulation parameters for mTc-MEP with the use of TIVA and D-wave monitoring. SIGNIFICANCE For mTc-MEP monitoring, a table is provided in which the recommended stimulation parameters are stated.
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Affiliation(s)
- S E Dulfer
- Department of Neurosurgery, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands.
| | - M C Gadella
- Department of Neurosurgery, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
| | - M M Sahinovic
- Department of Anaesthesiology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
| | - F Lange
- Department of Neurology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
| | - A R Absalom
- Department of Anaesthesiology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
| | - R J M Groen
- Department of Neurosurgery, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
| | - A Szelényi
- Department of Neurosurgery, Hospital of the Ludwig Maximilians University Munich (LMU), Munich, Germany
| | - G Drost
- Department of Neurosurgery, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands; Department of Neurology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
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Dulfer SE, Lange F, Sahinovic MM, Wapstra FH, Absalom AR, Faber C, Groen RJM, Drost G. Feasibility and optimal choice of stimulation parameters for supramaximal stimulation of motor evoked potentials. J Clin Monit Comput 2023; 37:783-793. [PMID: 36635569 PMCID: PMC10175431 DOI: 10.1007/s10877-022-00972-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/08/2022] [Accepted: 12/31/2022] [Indexed: 01/14/2023]
Abstract
PURPOSE The aim was to investigate the feasibility and optimal stimulation parameters for supramaximal stimulation of muscle recorded transcranial electrical stimulation motor evoked potentials (mTc-MEP). METHODS Forty-seven consecutive patients that underwent scoliosis surgery were included. First, the feasibility of supramaximal stimulation was assessed for two settings (setting 1: pulse duration 0.075ms, interstimulus interval (ISI) 1.5ms; setting 2: pulse duration 0.300ms, ISI 3ms). Thereafter, three mTc-MEP parameters were considered for both settings; (1) elicitability, (2) amplitude, and (3) if supramaximal stimulation was achieved with ≥ 20 V below maximum output. Finally, ISIs (1ms-4ms) were optimized for setting 1. RESULTS Nine patients (19.15%) were excluded. Of the remaining patients, supramaximal stimulation was achieved in all patients for setting 1, and in 26 (68.42%) for setting 2. In one patient, mTc-MEPs were elicitable in more muscles for setting (1) Amplitudes were not significantly different. Stimulation voltage could be increased ≥ 20 V in all 38 patients for setting 1 and in 10 (38.46%) for setting (2) Optimal ISI's differed widely. CONCLUSION We recommend using setting 1 when monitoring mTc-MEPs with supramaximal stimulation, after which an individualized ISI optimization can be performed. Moreover, when using supramaximal stimulation, short ISI's (i.e. 1ms or 1.5ms) can be the optimal ISI for obtaining the highest mTc-MEP amplitude.
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Affiliation(s)
- S E Dulfer
- Department of Neurosurgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. .,, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands.
| | - F Lange
- Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - M M Sahinovic
- Department of Anesthesiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - F H Wapstra
- Department of Orthopedics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - A R Absalom
- Department of Anesthesiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - C Faber
- Department of Orthopedics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - R J M Groen
- Department of Neurosurgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - G Drost
- Department of Neurosurgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Latency of subthalamic nucleus deep brain stimulation-evoked cortical activity as a potential biomarker for postoperative motor side effects. Clin Neurophysiol 2020; 131:1221-1229. [PMID: 32299006 DOI: 10.1016/j.clinph.2020.02.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 02/07/2020] [Accepted: 02/11/2020] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Here, we investigate whether cortical activation predicts motor side effects of deep brain stimulation (DBS) and whether these potential biomarkers have utility under general anesthesia. METHODS We recorded scalp potentials elicited by DBS during surgery (n = 11), both awake and under general anesthesia, and in an independent ambulatory cohort (n = 8). Across a range of stimulus configurations, we measured the amplitude and timing of short- and long-latency response components and linked them to motor side effects. RESULTS Regardless of anesthesia state, in both cohorts, DBS settings with capsular side effects elicited early responses with peak latencies clustering at <1 ms. This early response was preserved under anesthesia in all participants (11/11). In contrast, the long-latency components were suppressed completely in 6/11 participants. Finally, the latency of the earliest response could predict the presence of postoperative motor side effects both awake and under general anesthesia (84.8% and 75.8% accuracy, awake and under anesthesia, respectively). CONCLUSION DBS elicits short-latency cortical activation, both awake and under general anesthesia, which appears to reveal interactions between the stimulus and the corticospinal tract. SIGNIFICANCE Short-latency evoked cortical activity can potentially be used to aid both DBS lead placement and post-operative programming.
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Abalkhail TM, MacDonald DB, AlThubaiti I, AlOtaibi FA, Stigsby B, Mokeem AA, AlHamoud IA, Hassounah MI, Baz SM, AlSemari A, AlDhalaan HM, Khan S. Intraoperative direct cortical stimulation motor evoked potentials: Stimulus parameter recommendations based on rheobase and chronaxie. Clin Neurophysiol 2017; 128:2300-2308. [PMID: 29035822 DOI: 10.1016/j.clinph.2017.09.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 08/04/2017] [Accepted: 09/19/2017] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To determine optimal interstimulus interval (ISI) and pulse duration (D) for direct cortical stimulation (DCS) motor evoked potentials (MEPs) based on rheobase and chronaxie derived with two techniques. METHODS In 20 patients under propofol/remifentanil anesthesia, 5-pulse DCS thenar MEP rheobase and chronaxie with 2, 3, 4 and 5ms ISI were measured by linear regression of five charge thresholds at 0.05, 0.1, 0.2, 0.5 and 1msD, and estimated from two charge thresholds at 0.1 and 1msD using simple arithmetic. Optimal parameters were defined by minimum threshold energy: the ISI with lowest rheobase2×chronaxie, and D at its chronaxie. Near-optimal was defined as threshold energy <25% above minimum. RESULTS The optimal ISI was 3 or 4 (n=7 each), 2 (n=4), or 5ms (n=2), but only 4ms was always either optimal or near-optimal. The optimal D was ∼0.2 (n=12), ∼0.1 (n=7) or ∼0.3ms (n=1). Two-point estimates closely approximated five-point measurements. CONCLUSIONS Optimal ISI/D varies, with 4ms/0.2ms being most consistently optimal or near-optimal. Two-point estimation is sufficiently accurate. SIGNIFICANCE The results endorse 4ms ISI and 0.2msD for general use. Two-point estimation could enable quick individual optimization.
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Affiliation(s)
- Tariq M Abalkhail
- Section of Neurophysiology, Department of Neurosciences, King Faisal Specialist Hospital & Research Center (KFSH), Saudi Arabia
| | - David B MacDonald
- Section of Neurophysiology, Department of Neurosciences, King Faisal Specialist Hospital & Research Center (KFSH), Saudi Arabia.
| | - Ibrahim AlThubaiti
- Section of Neurosurgery, Department of Neurosciences, KFSH, Saudi Arabia
| | - Faisal A AlOtaibi
- Section of Neurosurgery, Department of Neurosciences, KFSH, Saudi Arabia
| | - Bent Stigsby
- Section of Neurophysiology, Department of Neurosciences, King Faisal Specialist Hospital & Research Center (KFSH), Saudi Arabia
| | - Amal A Mokeem
- Section of Neurophysiology, Department of Neurosciences, King Faisal Specialist Hospital & Research Center (KFSH), Saudi Arabia
| | - Iftetah A AlHamoud
- Section of Neurophysiology, Department of Neurosciences, King Faisal Specialist Hospital & Research Center (KFSH), Saudi Arabia
| | - Maher I Hassounah
- Section of Neurosurgery, Department of Neurosciences, KFSH, Saudi Arabia
| | - Salah M Baz
- Section of Neurology, Department of Neurosciences, KFSH, Saudi Arabia
| | | | - Hesham M AlDhalaan
- Section of Pediatric Neurology, Department of Neurosciences, KFSH, Saudi Arabia
| | - Sameena Khan
- Section of Pediatric Neurology, Department of Neurosciences, KFSH, Saudi Arabia
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Massé-Alarie H, Elgueta Cancino E, Schneider C, Hodges P. Paired-Pulse TMS and Fine-Wire Recordings Reveal Short-Interval Intracortical Inhibition and Facilitation of Deep Multifidus Muscle Fascicles. PLoS One 2016; 11:e0159391. [PMID: 27509086 PMCID: PMC4980005 DOI: 10.1371/journal.pone.0159391] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 07/03/2016] [Indexed: 11/19/2022] Open
Abstract
Objective Paired-pulse transcranial magnetic stimulation (ppTMS) is used to probe inhibitory and excitatory networks within the primary motor cortex (M1). These mechanisms are identified for limb muscles but it is unclear whether they share properties with trunk muscles. The aim was to determine whether it was possible to test the intracortical inhibition and facilitation of the deep multifidus muscle fascicles (DM) and at which inter-stimulus intervals (ISI). Methods In ten pain-free individuals, TMS was applied over M1 and motor evoked potentials (MEP) were recorded using fine-wire electrodes in DM. MEPs were conditioned with subthreshold stimuli at ISIs of 1 to 12 ms to test short-interval intracortical inhibition (SICI) and at 15 ms for long-interval intracortical facilitation. Short-interval facilitation (SICF) was tested using 1-ms ISI. Results SICI of DM was consistently obtained with ISI of 1-, 3-, 4- and 12-ms. Facilitation of DM MEP was only identified using SICF paradigm. Conclusions A similar pattern of MEP modulation with ISI changes for deep trunk and limb muscles implies that M1 networks share some functional properties. Significance The ppTMS paradigm presents a potential to determine how M1 inhibitory and excitatory mechanisms participate in brain re-organization in back pain that affects control of trunk muscles.
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Affiliation(s)
- Hugo Massé-Alarie
- Laboratory of Clinical Neuroscience and neuroStimulation, Université Laval (Dept of Rehabilitation), CHU de Québec Research Center, Neuroscience Unit (CHUL), Quebec City, QC, Canada
| | - Edith Elgueta Cancino
- The University of Queensland, NHMRC Centre of Clinical Research Excellence in Spinal Pain, Injury & Health, School of Health & Rehabilitation Sciences, Brisbane, Qld Australia
| | - Cyril Schneider
- Laboratory of Clinical Neuroscience and neuroStimulation, Université Laval (Dept of Rehabilitation), CHU de Québec Research Center, Neuroscience Unit (CHUL), Quebec City, QC, Canada
| | - Paul Hodges
- The University of Queensland, NHMRC Centre of Clinical Research Excellence in Spinal Pain, Injury & Health, School of Health & Rehabilitation Sciences, Brisbane, Qld Australia
- * E-mail:
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Optimal parameters of transcranial electrical stimulation for intraoperative monitoring of motor evoked potentials of the tibialis anterior muscle during pediatric scoliosis surgery. Neurophysiol Clin 2013; 43:243-50. [PMID: 24094910 DOI: 10.1016/j.neucli.2013.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 06/05/2013] [Accepted: 08/04/2013] [Indexed: 11/21/2022] Open
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Optimum interpulse interval for transcranial electrical train stimulation to elicit motor evoked potentials of maximal amplitude in both upper and lower extremity target muscles. Clin Neurophysiol 2013; 124:2054-9. [DOI: 10.1016/j.clinph.2013.04.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Revised: 03/20/2013] [Accepted: 04/12/2013] [Indexed: 11/18/2022]
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Horton TG, Barnes M, Johnson S, Kalapos PC, Link A, Cockroft KM. Feasibility and efficacy of transcranial motor-evoked potential monitoring in neuroendovascular surgery. AJNR Am J Neuroradiol 2012; 33:1825-31. [PMID: 22517278 DOI: 10.3174/ajnr.a3017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Neurophysiological monitoring for neuroendovascular procedures typically involves EEG and SSEP monitoring via cutaneous electrodes. MEP monitoring has been used less frequently because, traditionally, this has required subdural electrode placement. With the advent of transcutaneous techniques, MEP monitoring use has increased. However, little has been published regarding the use of this technique in therapeutic neuroendovascular procedures. The purpose of this study was therefore to determine whether TcMEP monitoring is feasible and efficacious in therapeutic neuroendovascular procedures. MATERIALS AND METHODS We retrospectively reviewed our data base of therapeutic neuroendovascular procedures performed with the use of TcMEP monitoring. We specifically determined the incidence of TcMEP changes compared with changes in either SSEP or EEG. We then correlated these changes to actual adverse neurologic events. RESULTS Although TcMEP monitoring was technically successful in all of the 140 patients in which it was attempted, we observed significant changes in TcMEP signals in only 1 patient. This patient experienced changes involving all 3 monitoring modalities after intraprocedural aneurysm rupture. In contrast, changes in SSEP tracings alone were found in 9 patients. Of these, 2 patients were known to be moribund before their procedures and neither recovered. Among the remaining 7 patients, temporary SSEP changes tended to correlate with temporary neurologic deficits, while permanent changes were associated with permanent or long-lasting deficits. CONCLUSIONS These results suggest that TcMEP monitoring is feasible in therapeutic neuroendovascular procedures. However, it appears that the addition of TcMEP monitoring provides no added benefit to SSEP and EEG monitoring alone.
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Affiliation(s)
- T G Horton
- Department of Neurosurgery, Penn State Hershey Medical Center, Hershey, Pennsylvania 17033, USA
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Groppa S, Werner-Petroll N, Münchau A, Deuschl G, Ruschworth MF, Siebner HR. A novel dual-site transcranial magnetic stimulation paradigm to probe fast facilitatory inputs from ipsilateral dorsal premotor cortex to primary motor cortex. Neuroimage 2012; 62:500-9. [DOI: 10.1016/j.neuroimage.2012.05.023] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 05/07/2012] [Accepted: 05/09/2012] [Indexed: 11/25/2022] Open
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Novak K, Oberndorfer S. Electrophysiology and intraoperative neurophysiological monitoring. HANDBOOK OF CLINICAL NEUROLOGY 2012; 104:149-161. [PMID: 22230442 DOI: 10.1016/b978-0-444-52138-5.00012-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Affiliation(s)
- Klaus Novak
- Department of Neurosurgery, Medical University of Vienna, Vienna, Austria.
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Bawa P, Chalmers G. Responses of human motoneurons to high-frequency stimulation of Ia afferents. Muscle Nerve 2009; 38:1604-15. [PMID: 19016548 DOI: 10.1002/mus.21184] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study was designed to extend to humans the findings of classical studies on anesthetized cats, which have examined the discharge of spinal motoneurons in response to high-frequency stimulus trains delivered to Ia afferents. Experiments were conducted on the monosynaptic pathway in the flexor carpi radialis (FCR) and soleus muscles. Subjects maintained a rhythmic discharge of a single motor unit (SMU) in either the FCR or soleus while homonymous Ia afferents were stimulated with either a single- or multipulse train. An n@IPI stimulus train had n pulses (n = 2-4) and an interpulse interval (IPI) of 1-8 ms. For each condition and motor unit, surface electromyographic (EMG) activity was averaged, and peristimulus-time histograms (PSTHs) were constructed for the SMU. The magnitude of the EMG was high for IPI = 1 ms, low for IPI = 2-3 ms, and high for IPI = 4-8 ms. SMU responses showed a similar pattern, which indicated that the increased EMG response was due to the presence of multiple peaks in a PSTH. The key results indicate that: (1) a short, high-frequency stimulus train enhances the discharge probability of a motoneuron above that observed with a single pulse; and (2) the increased motoneuron responses are significantly greater for the FCR than for the soleus muscle.
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Affiliation(s)
- Parveen Bawa
- School of Kinesiology, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
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Casotti G, Rieser-Danner L, Knabb MT. Successful implementation of inquiry-based physiology laboratories in undergraduate major and nonmajor courses. ADVANCES IN PHYSIOLOGY EDUCATION 2008; 32:286-296. [PMID: 19047505 DOI: 10.1152/advan.00100.2007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Recent evidence has demonstrated that inquiry-based physiology laboratories improve students' critical- and analytical-thinking skills. We implemented inquiry-based learning into three physiology courses: Comparative Vertebrate Physiology (majors), Human Physiology (majors), and Human Anatomy and Physiology (nonmajors). The aims of our curricular modifications were to improve the teaching of physiological concepts, teach students the scientific approach, and promote creative and critical thinking. We assessed our modifications using formative (laboratory exams, oral presentations, and laboratory reports) and summative evaluations (surveys, laboratory notebook, and an end of semester project). Students appreciated the freedom offered by the new curriculum and the opportunity to engage in the inquiry process. Results from both forms of evaluation showed a marked improvement due to the curricular revisions. Our analyses indicate an increased confidence in students' ability to formulate questions and hypotheses, design experiments, collect and analyze data, and make conclusions. Thus, we have successfully incorporated inquiry-based laboratories in both major and nonmajor courses.
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Affiliation(s)
- G Casotti
- Department of Biology, West Chester University of Pennsylvania, West Chester, PA 19383, USA.
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Abstract
High-frequency stimulation of peripheral nerve bundles is frequently used in clinical tests and physiologic experiments to study presynaptic and postsynaptic effects. To understand the postsynaptic effects, it is important to ensure that each pulse in the train is equally effective in stimulating the presynaptic nerve bundle; however, the optimal interpulse interval (IPI) and the stimulus intensity at which each pulse is equally effective in stimulating the same number of axons are not known. The magnitude of the compound action potential produced by each pulse in a train was tested on the sural nerve of 4 healthy human subjects. The stimulus train (2–4 pulses) was applied to the sural nerve at the lateral malleolus, and neural responses were recorded from just below the knee. With 2-pulse trains, families of curves between IPIs (1–6 ms) and normalized amplitudes of the second response were plotted for different stimulus intensities. Visual inspection of the data showed that the curves fell into 2 groups: with stimulus intensities <2.5× perception threshold (Th), the test response appeared partially at longer IPIs, whereas with stimulus intensities ≥3× Th, partial recovery of the test response was earlier. The interval for complete recovery was statistically the same for low- and high-intensity stimulation. With more than 2 pulses in a stimulus train (IPI = 5 ms), the amplitude of the compound action potential (CAP) was not affected significantly. These results are important in understanding both the presynaptic and postsynaptic responses when presynaptic axon bundles are stimulated at high frequencies.
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Affiliation(s)
- Paige Stevens
- School of Kinesiology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Parveen Bawa
- School of Kinesiology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
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Deletis V, Sala F. Intraoperative neurophysiological monitoring of the spinal cord during spinal cord and spine surgery: a review focus on the corticospinal tracts. Clin Neurophysiol 2007; 119:248-64. [PMID: 18053764 DOI: 10.1016/j.clinph.2007.09.135] [Citation(s) in RCA: 248] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2003] [Revised: 09/05/2007] [Accepted: 09/07/2007] [Indexed: 12/28/2022]
Abstract
Recent advances in technology and the refinement of neurophysiological methodologies are significantly changing intraoperative neurophysiological monitoring (IOM) of the spinal cord. This review will summarize the latest achievements in the monitoring of the spinal cord during spine and spinal cord surgeries. This overview is based on an extensive review of the literature and the authors' personal experience. Landmark articles and neurophysiological techniques have been briefly reported to contextualize the development of new techniques. This background is extended to describe the methodological approach to intraoperatively elicit and record spinal D wave and muscle motor evoked potentials (muscle MEPs). The clinical application of spinal D wave and muscle MEP recordings is critically reviewed (especially in the field of Neurosurgery) and new developments such as mapping of the dorsal columns and the corticospinal tracts are presented. In the past decade, motor evoked potential recording following transcranial electrical stimulation has emerged as a reliable technique to intraoperatively assess the functional integrity of the motor pathways. Criteria based on the absence/presence of potentials, their morphology and threshold-related parameters have been proposed for muscle MEPs. While the debate remains open, it appears that different criteria may be applied for different procedures according to the expected surgery-related morbidity and the ultimate goal of the surgeon (e.g. total tumor removal versus complete absence of transitory or permanent neurological deficits). On the other hand, D wave changes--when recordable--have proven to be the strongest predictors of maintained corticospinal tract integrity (and therefore, of motor function/recovery). Combining the use of muscle MEPs with D wave recordings provides the most comprehensive approach for assessing the functional integrity of the spinal cord motor tracts during surgery for intramedullary spinal cord tumors. However, muscle MEPs may suffice to assess motor pathways during other spinal procedures and in cases where the pathophysiology of spinal cord injury is purely ischemic. Finally, while MEPs are now considered the gold standard for monitoring the motor pathways, SEPs continue to retain value as they provide specificity for assessing the integrity of the dorsal column. However, we believe SEPs should not be used exclusively--or as an alternative to motor evoked potentials--during spine surgery, but rather as a complementary method in combination with MEPs. For intramedullary spinal tumor resection, SEPs should not be used exclusively without MEPs.
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Affiliation(s)
- Vedran Deletis
- Institute for Neurology and Neurosurgery, Beth Israel Medical Center-Singer Division, 170 East End Avenue, Room 311, New York, NY 10128, USA.
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Szelényi A, Kothbauer KF, Deletis V. Transcranial electric stimulation for intraoperative motor evoked potential monitoring: Stimulation parameters and electrode montages. Clin Neurophysiol 2007; 118:1586-95. [PMID: 17507288 DOI: 10.1016/j.clinph.2007.04.008] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Revised: 03/08/2007] [Accepted: 04/14/2007] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To evaluate the efficacy of constant current transcranial electric stimulation (TES) parameters for eliciting muscle motor evoked potentials (MEPs) in the abductor pollicis brevis muscles (APB) and the tibialis anterior muscles (TA). The following parameters were tested intraoperatively: interstimulus interval (ISI), individual stimulation pulse duration within a train of five stimuli. Different montages of stimulating electrodes were assessed for effectiveness and focality. Further, reference values for APB and TA motor thresholds in neurosurgical patients with normal motor status under total intravenous anesthesia were determined. METHODS Motor thresholds of contralateral muscle MEPs were determined at 0.1, 0.2, 0.4, and 0.5 ms pulse duration and ISIs of 2, 3, 4, and 5 ms using a train of five monophasic constant current pulses with C3/C4 (27 patients). The stimulating electrodes were positioned at C1, C2, C3, C4, Cz, and Cz+6 cm. Different montages were used to determine the most effective and the most focal stimulation montages for the APB and TA muscles (30 patients). Eighty-six patients with clinically normal motor function were studied for motor threshold reference values. RESULTS The prolongation of the pulse duration has the strongest effect to decrease the motor threshold, which proportionally increases the delivered charge. The lowest stimulation threshold to elicit muscle MEPs in the APB and TA muscles is achieved with a train of stimuli consisting of an individual stimulus pulse duration of 0.5 ms. An ISI of 4 ms gave the lowest motor thresholds, but did not reach statistical significance compared to 3 ms. The stimulating electrode montage C3/C4 (C4/C3) allows for the lowest stimulation thresholds, but the vigorous muscle contractions it has is a disadvantage. The most focal stimulating electrode montages for the contralateral APB muscles are C3/Cz and C4/Cz, respectively, and for the TA muscles Cz/Cz+6 cm. CONCLUSIONS In adult neurosurgical patients with a normal motor status under total intravenous anesthesia, an individual pulse duration of 0.5 ms and an ISI of 4 ms provide the lowest motor thresholds. Pragmatically, C1/C2, resp., C2/C1 montage provides monitorable responses in both APB and TA muscles at reasonable stimulation thresholds without inducing movements disturbing surgery and especially microdissection. If the most focal hemispheric stimulation for the distal upper extremity muscles is required, the use of C3 or C4 referenced to Cz is recommended. SIGNIFICANCE The stimulation parameters within a train of five pulses with an individual pulse duration of 0.5 ms and an ISI of 4 ms provide the lowest motor threshold. These data confirm not only studies for D wave recovery but also provide optimal stimulation parameters for intraoperative near threshold stimulation.
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Affiliation(s)
- Andrea Szelényi
- Department of Neurosurgery, Klinikum der Johann Wolfgang Goethe Universität, Frankfurt/Main, Germany.
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Abstract
Previous results using paired-pulse transcranial magnetic stimulation (TMS) have suggested that the excitability of transcallosal (TC) connections between the hand areas of the two motor cortices is modulated by intracortical inhibitory circuits in the same way as corticospinal tract (CTS) projections to spinal motoneurons. Here we describe two further similarities in TC and CTS control using (1) an I-wave facilitation protocol and (2) preconditioning with rTMS. In experiment 1, excitability of TC pathways was measured using interhemispheric inhibition (IHI) and the ipsilateral silent period (iSP), whilst excitability of CTS pathways was measured by recording the EMG response evoked in the first dorsal interosseous muscle contralateral to the conditioning stimulus (cMEP). The intensity of the conditioning stimulus was first adjusted to threshold for evoking IHI and iSP, then pairs of conditioning stimuli were applied randomly at interstimulus intervals (ISIs) from 1.3 to 4.3 ms. IHI and iSP were facilitated at ISI=1.5 ms and 3.0 ms, respectively, as was the MEP evoked by the conditioning stimuli in the contralateral hand. We suggest that TC projections receive I-wave-like facilitation similar to that seen in CTS projections. In experiment 2, short interval inhibition of the iSP (SICIiSP), and short interval intracortical inhibition of the cMEP (SICIcMEP) were examined before and after 600 pulses of 5 Hz rTMS at 90% resting motor threshold. Both SICIiSP and SICIcMEP were reduced, as was the iSP; the cMEP was unchanged. This shows that the population of inhibitory interneurons that control TC neurons respond in the same way to 5 Hz rTMS as those that control CTS neurons. Taken together, the data from the two experiments suggest that the layer III and layer V pyramidal neurons that give rise to TC and CTS pathways, respectively, are controlled by neuronal circuitry with similar properties.
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Affiliation(s)
- L Avanzino
- Sobell Department of Motor Neuroscience and Movement Disorders, Box 66, Institute of Neurology, Queen Square, London WC1N 3BG, UK
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Macdonald DB. Intraoperative Motor Evoked Potential Monitoring: Overview and Update. J Clin Monit Comput 2006; 20:347-77. [PMID: 16832580 DOI: 10.1007/s10877-006-9033-0] [Citation(s) in RCA: 192] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Accepted: 05/23/2006] [Indexed: 01/20/2023]
Abstract
Amidst controversy about methodology and safety, intraoperative neurophysiology has entered a new era of increasingly routine transcranial and direct electrical brain stimulation for motor evoked potential (MEP) monitoring. Based on literature review and illustrative clinical experience, this tutorial aims to present a balanced overview for experienced practitioners, surgeons and anesthesiologists as well as those new to the field. It details the physiologic basis, indications and methodology of current MEP monitoring techniques, evaluates their safety, explores interpretive controversies and outlines some applications and results, including aortic aneurysm, intramedullary spinal cord tumor, spinal deformity, posterior fossa tumor, intracranial aneurysm and peri-rolandic brain surgeries. The many advances in motor system assessment achieved in the last two decades undoubtedly improve monitoring efficacy without unduly compromising safety. Future studies and experience will likely clarify existing controversies and bring further advances.
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Affiliation(s)
- David B Macdonald
- Department of Neurosciences, King Faisal Specialist Hospital & Research Center, MBC 76, PO Box 3354, Riyadh 11211, Saudi Arabia.
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Holdefer RN, Sadleir R, Russell MJ. Predicted current densities in the brain during transcranial electrical stimulation. Clin Neurophysiol 2006; 117:1388-97. [PMID: 16644273 PMCID: PMC2426751 DOI: 10.1016/j.clinph.2006.02.020] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2004] [Revised: 01/22/2006] [Accepted: 02/13/2006] [Indexed: 11/15/2022]
Abstract
OBJECTIVE We sought an electrical modeling approach to evaluate the potential application of finite element method (FEM) modeling to predict current pathways and intensities in the brain after transcranial electrical stimulation. METHODS A single coronal MRI section through the head, including motor cortex, was modeled using FEM. White matter compartments with both anatomically realistic anisotropies in resistivity and with a homogeneous resistivity were modeled. Current densities in the brain were predicted for electrode sites on the scalp and after theoretical application of a conductive head restraint device. RESULTS Localized current densities were predicted for the model with white matter anisotropies. Differences in predicted peak current densities were related to location of stimulation sites relative to deep sulci in the brain and scalp shunting that was predicted to increase with inter-electrode proximity. A conductive head restraint device was predicted to shunt current away from the brain when a constant current source was used. CONCLUSIONS The complex geometry of different tissue compartments in the head and their contrasting resistivities may jointly determine the strength and location of current densities in the brain after transcranial stimulation. This might be predictable with FEM incorporating white matter anisotropies. Conductive head restraint devices during surgery may be contraindicated with constant current stimulation. SIGNIFICANCE Individually optimized tcMEP monitoring and localized transcranial activation in the brain might be possible through FEM modeling.
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Deletis V. Chapter 15 Intraoperative neurophysiology of the corticospinal tract of the spinal cord. SUPPLEMENTS TO CLINICAL NEUROPHYSIOLOGY 2006; 59:107-12. [PMID: 16893100 DOI: 10.1016/s1567-424x(09)70019-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Affiliation(s)
- Vedran Deletis
- Institute for Neurology and Neurosurgery, St. Luke's-Roosevelt Hospital, 1000 10th Avenue, New York, NY 10019-1147, USA.
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