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Jamaludin MR, Lai KW, Chuah JH, Zaki MA, Hum YC, Tee YK, Mohd Salim MI, Saw LB. Transcranial Electrical Motor Evoked Potential in Predicting Positive Functional Outcome of Patients after Decompressive Spine Surgery: Review on Challenges and Recommendations towards Objective Interpretation. Behav Neurol 2021; 2021:2684855. [PMID: 34777631 PMCID: PMC8580690 DOI: 10.1155/2021/2684855] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 10/18/2021] [Indexed: 11/18/2022] Open
Abstract
Spine surgeries impose risk to the spine's surrounding anatomical and physiological structures especially the spinal cord and the nerve roots. Intraoperative neuromonitoring (IONM) is a technology developed to monitor the integrity of the spinal cord and the nerve roots via the surgery. Transcranial motor evoked potential (TcMEP) (one of the IONM modalities) is adopted to monitor the integrity of the motor pathway of the spinal cord and the motor nerve roots. Recent research suggested that the IONM is conducive as a prognostic tool towards the patient's functional outcome. This paper summarizes the researches of IONM being adopted as a prognostic tool. In addition, this paper highlights the problems associated with the signal parameters as the improvement criteria in the previous researches. Lastly, we review the challenges of TcMEP to achieve a prognostic tool focusing on the factors that could interfere with the generation of a stable TcMEP response. The final section will discuss recommendations for IONM technology to achieve an objective prognostic tool.
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Affiliation(s)
- Mohd Redzuan Jamaludin
- Department of Biomedical Engineering, Faculty of Engineering, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | - Khin Wee Lai
- Department of Biomedical Engineering, Faculty of Engineering, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | - Joon Huang Chuah
- Department of Electrical Engineering, Faculty of Engineering, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | - Muhammad Afiq Zaki
- Center of Environmental Health and Safety, Faculty of Health Sciences, Universiti Teknologi Mara Selangor, Puncak Alam Campus, 42300 Bandar Puncak Alam, Selangor Darul Ehsan, Malaysia
| | - Yan Chai Hum
- Centre for Healthcare Science & Technology, Department of Mechatronics and Biomedical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Malaysia
| | - Yee Kai Tee
- Centre for Healthcare Science & Technology, Department of Mechatronics and Biomedical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Malaysia
| | - Maheza Irna Mohd Salim
- Bioinspired Device and Tissue Engineering Research Group, School of Biomedical Engineering and Health Sciences, Faculty of Engineering, Universiti Teknologi Malaysia, 81300 Skudai, Johor, Malaysia
| | - Lim Beng Saw
- Department of Orthopaedic Surgery, Sunway Medical Centre, Malaysia
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Yamada S, Enatsu R, Kimura Y, Komatsu K, Akiyama Y, Mikami T, Ochi S, Mikuni N. Effects of polarity of bipolar sensorimotor direct cortical stimulation on intraoperative motor evoked potentials. Clin Neurophysiol 2021; 132:2351-2356. [PMID: 34454261 DOI: 10.1016/j.clinph.2021.06.032] [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: 11/25/2020] [Revised: 05/24/2021] [Accepted: 06/21/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVE The present study investigated the effects of the stimulus polarity and location of motor evoked potential (MEP) to establish a stimulation protocol. METHODS Nineteen patients who intraoperatively underwent MEP in bipolar direct cortical stimulation were enrolled in the present study. Somatosensory evoked potentials (SEP) of the contralateral median nerve stimulation were recorded to determine stimulation sites. MEP was performed under two settings in all patients: 1. Anodal bipolar stimulation: an anode on the precentral gyrus and a cathode on the postcentral gyrus, 2. Cathodal bipolar stimulation: a cathode on the precentral gyrus and an anode on the postcentral gyrus. MEP amplitudes and the coefficient of variation (CV) at a stimulation intensity of 25 mA and the thresholds of induced MEP were compared between the two settings. RESULTS An electrical stimulation at 25 mA induced a significantly higher amplitude in cathodal bipolar stimulation than in anodal bipolar stimulation. Cathodal bipolar stimulation also showed significantly lower thresholds than anodal stimulation. CV did not significantly differ between the two groups. CONCLUSIONS These results indicate that cathodal bipolar stimulation is superior to anodal bipolar stimulation for intraoperative MEP monitoring. SIGNIFICANCE MEP in cathodal bipolar cortical stimulation may be used in a safe and useful evaluation method of motor fiber damage that combines sensitivity and specificity.
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Affiliation(s)
- Shoto Yamada
- Division of Clinical Engineering, Sapporo Medical University Hospital, Sapporo, Japan
| | - Rei Enatsu
- Department of Neurosurgery, Sapporo Medical University Hospital, Sapporo, Japan.
| | - Yusuke Kimura
- Department of Neurosurgery, Sapporo Medical University Hospital, Sapporo, Japan
| | - Katsuya Komatsu
- Department of Neurosurgery, Sapporo Medical University Hospital, Sapporo, Japan
| | - Yukinori Akiyama
- Department of Neurosurgery, Sapporo Medical University Hospital, Sapporo, Japan
| | - Takeshi Mikami
- Department of Neurosurgery, Sapporo Medical University Hospital, Sapporo, Japan
| | - Satoko Ochi
- Department of Neurosurgery, Sapporo Medical University Hospital, Sapporo, Japan
| | - Nobuhiro Mikuni
- Department of Neurosurgery, Sapporo Medical University Hospital, Sapporo, Japan
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Asimakidou E, Abut PA, Raabe A, Seidel K. Motor Evoked Potential Warning Criteria in Supratentorial Surgery: A Scoping Review. Cancers (Basel) 2021; 13:2803. [PMID: 34199853 PMCID: PMC8200078 DOI: 10.3390/cancers13112803] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/30/2021] [Accepted: 05/31/2021] [Indexed: 12/31/2022] Open
Abstract
During intraoperative monitoring of motor evoked potentials (MEP), heterogeneity across studies in terms of study populations, intraoperative settings, applied warning criteria, and outcome reporting exists. A scoping review of MEP warning criteria in supratentorial surgery was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). Sixty-eight studies fulfilled the eligibility criteria. The most commonly used alarm criteria were MEP signal loss, which was always a major warning sign, followed by amplitude reduction and threshold elevation. Irreversible MEP alterations were associated with a higher number of transient and persisting motor deficits compared with the reversible changes. In almost all studies, specificity and Negative Predictive Value (NPV) were high, while in most of them, sensitivity and Positive Predictive Value (PPV) were rather low or modest. Thus, the absence of an irreversible alteration may reassure the neurosurgeon that the patient will not suffer a motor deficit in the short-term and long-term follow-up. Further, MEPs perform well as surrogate markers, and reversible MEP deteriorations after successful intervention indicate motor function preservation postoperatively. However, in future studies, a consensus regarding the definitions of MEP alteration, critical duration of alterations, and outcome reporting should be determined.
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Affiliation(s)
- Evridiki Asimakidou
- Department of Neurosurgery, Inselspital, Bern University Hospital, 3010 Bern, Switzerland; (E.A.); (P.A.A.); (A.R.)
| | - Pablo Alvarez Abut
- Department of Neurosurgery, Inselspital, Bern University Hospital, 3010 Bern, Switzerland; (E.A.); (P.A.A.); (A.R.)
- Department of Neurosurgery, Clínica 25 de Mayo, 7600 Mar del Plata, Argentina
| | - Andreas Raabe
- Department of Neurosurgery, Inselspital, Bern University Hospital, 3010 Bern, Switzerland; (E.A.); (P.A.A.); (A.R.)
| | - Kathleen Seidel
- Department of Neurosurgery, Inselspital, Bern University Hospital, 3010 Bern, Switzerland; (E.A.); (P.A.A.); (A.R.)
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Kameda M, Hishikawa T, Hiramatsu M, Yasuhara T, Kurozumi K, Date I. Precise MEP monitoring with a reduced interval is safe and useful for detecting permissive duration for temporary clipping. Sci Rep 2020; 10:3507. [PMID: 32103082 PMCID: PMC7044220 DOI: 10.1038/s41598-020-60377-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 02/11/2020] [Indexed: 12/14/2022] Open
Abstract
Although temporary clipping of the parent artery is an indispensable technique in clipping surgery for intracranial aneurysms, the permissive duration of temporary clipping is still not well known. The aim of this study is to confirm the safety of precise motor evoked potential (MEP) monitoring and to estimate the permissive duration of temporary clipping for middle cerebral artery (MCA) aneurysm based on precise MEP monitoring results. Under precise MEP monitoring via direct cortical stimulation every 30 seconds to 1 minute, surgeons released a temporary clip and waited for MEP amplitude to recover following severe (>50%) reduction of MEP amplitude during temporary clipping. Precise MEP monitoring was safely performed. Twenty-eight instances of temporary clipping were performed in 42 MCA aneurysm clipping surgeries. Because precise MEP monitoring could be used to determine when to release a temporary clip even with a severe reduction in MEP amplitude due to lengthy temporary clipping, no patients experienced permanent postoperative hemiparesis. Based on logistic regression analysis, if a temporary clip is applied for 312 seconds or more, there is a higher probability of a severe reduction in MEP amplitude. We should therefore release temporary clips after 5 minutes in order to avoid permanent postoperative hemiparesis.
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Affiliation(s)
- Masahiro Kameda
- Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama-Shi, Okayama, 700-8558, Japan.
| | - Tomohito Hishikawa
- Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama-Shi, Okayama, 700-8558, Japan
| | - Masafumi Hiramatsu
- Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama-Shi, Okayama, 700-8558, Japan
| | - Takao Yasuhara
- Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama-Shi, Okayama, 700-8558, Japan
| | - Kazuhiko Kurozumi
- Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama-Shi, Okayama, 700-8558, Japan
| | - Isao Date
- Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama-Shi, Okayama, 700-8558, Japan
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The role of tailored intraoperative neurophysiological monitoring in glioma surgery: a single institute experience. J Neurooncol 2020; 146:459-467. [PMID: 32020476 DOI: 10.1007/s11060-019-03347-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 11/15/2019] [Indexed: 10/25/2022]
Abstract
INTRODUCTION Glioma surgery near the functional area is still a dilemma. Intraoperative neurophysiologic monitoring (IONM) and functional mapping can play a role to maximize the extent of resection (EOR), while minimizing the risk of sequelae. We herein review the utility of tailored intraoperative mapping and monitoring in patients undergoing glioma surgery in our institute. METHODS Patients were divided into two groups on the basis of application tailored IONM (group A, 2013-2017, n = 53) or not (group B, 2008-2012, n = 49) between January 2008 and December 2017. The setup, tailored IONM protocols, surgery, and clinical results of all patients with eloquent glioma were analyzed with the EOR, functionality scores, overall survival (OS) and progression-free survival (PFS) retrospectively. RESULTS The 102 patients were considered eligible for analysis. High grade and low grade gliomas accounted for 73 (72%) and 29 (28%) cases, respectively. There was a positive association between the application of neuromonitor and post-operative functional preservation, but no significant statistical differences over the EOR, OS and PFS between the two groups. CONCLUSIONS In our experience, tailored intraoperative functional mapping provides an effective neurological function preservation. Routine implementation of neurophysiological monitoring with adequate pre-operative planning and intraoperative teamwork in eloquent glioma can get more satisfied functional preservation. Due to the maturation and experience of our IONM team may also be the variation factor, prospective studies with a more prominent sample and proper multivariate analysis will be expected to determine the real benefit.
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Abboud T, Schwarz C, Westphal M, Martens T. A comparison between threshold criterion and amplitude criterion in transcranial motor evoked potentials during surgery for supratentorial lesions. J Neurosurg 2019; 131:740-749. [PMID: 30192199 DOI: 10.3171/2018.4.jns172468] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 04/02/2018] [Indexed: 12/11/2022]
Abstract
OBJECTIVE The aim of this study was to compare sensitivity and specificity between the novel threshold and amplitude criteria for motor evoked potentials (MEPs) monitoring after transcranial electrical stimulation (TES) during surgery for supratentorial lesions in the same patient cohort. METHODS One hundred twenty-six patients were included. All procedures were performed under general anesthesia. Craniotomies did not expose motor cortex, so that direct mapping was less suitable. After TES, MEPs were recorded bilaterally from abductor pollicis brevis (APB), from orbicularis oris (OO), and/or from tibialis anterior (TA). The percentage increase in the threshold level was assessed and considered significant if it exceeded by more than 20% on the affected side the percentage increase on the unaffected side. Amplitude on the affected side was measured with a stimulus intensity of 150% of the threshold level set for each muscle. RESULTS Eighteen of 126 patients showed a significant change in the threshold level as well as an amplitude reduction of more than 50% in MEPs recorded from APB, and 15 of the patients had postoperative deterioration of motor function of the arm (temporary in 8 cases and permanent in 7 [true-positive and false-negative results]). Recording from TA was performed in 66 patients; 4 developed postoperative deterioration of motor function of the leg (temporary in 3 cases and permanent in 1), and showed a significant change in the threshold level, and an amplitude reduction of more than 50% occurred in 1 patient. An amplitude reduction of more than 50% occurred in another 10 patients, without a significant change in the threshold level or postoperative deterioration. Recording from OO was performed in 61 patients; 3 developed postoperative deterioration of motor function of facial muscles (temporary in 2 cases and permanent in 1) and had a significant change in the threshold level, and 2 of the patients had an amplitude reduction of more than 50%. Another 6 patients had an amplitude reduction of more than 50% but no significant change in the threshold level or postoperative deterioration.Sensitivity of the threshold criterion was 100% when MEPs were recorded from APB, OO, or TA, and its specificity was 97%, 100%, and 100%, respectively. Sensitivity of the amplitude criterion was 100%, 67%, and 25%, with a specificity of 97%, 90%, and 84%, respectively. CONCLUSIONS The threshold criterion was comparable to the amplitude criterion with a stimulus intensity set at 150% of the threshold level regarding sensitivity and specificity when recording MEPs from APB, and superior to it when recording from TA or OO.
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Affiliation(s)
- Tammam Abboud
- 1Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; and.,2Department of Neurosurgery, University Medical Center Göttingen, Göttingen, Germany
| | - Cindy Schwarz
- 1Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; and
| | - Manfred Westphal
- 1Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; and
| | - Tobias Martens
- 1Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; and
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Vespa S, Stumpp L, Bouckaert C, Delbeke J, Smets H, Cury J, Ferrao Santos S, Rooijakkers H, Nonclercq A, Raedt R, Vonck K, El Tahry R. Vagus Nerve Stimulation-Induced Laryngeal Motor Evoked Potentials: A Possible Biomarker of Effective Nerve Activation. Front Neurosci 2019; 13:880. [PMID: 31507360 PMCID: PMC6718640 DOI: 10.3389/fnins.2019.00880] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/05/2019] [Indexed: 11/13/2022] Open
Abstract
Vagus nerve stimulation (VNS) therapy is associated with laryngeal muscle activation and induces voice modifications, well-known side effects of the therapy resulting from co-activation of the recurrent laryngeal nerve. In this study, we describe the non-invasive transcutaneous recording of laryngeal motor evoked potentials (LMEPs), which could serve as a biomarker of effective nerve activation and individual titration in patients with drug-resistant epilepsy. We recruited drug-resistant epileptic patients treated for at least 6 months with a VNS. Trains of 600-1200 VNS pulses were delivered with increasing current outputs. We placed six skin electrodes on the ventral surface of the neck, in order to record LMEPs whenever the laryngeal muscular threshold was reached. We studied the internal consistency and the variability of LMEP recordings, and compared different methods for amplitude calculation. Recruitment curves were built based on the stimulus-response relationship. We also determined the electrical axis of the LMEPs dipole in order to define the optimal electrode placement for LMEPs recording in a clinical setting. LMEPs were successfully recorded in 11/11 patients. The LMEPs threshold ranged from 0.25 to 1 mA (median 0.50 mA), and onset latency was between 5.37 and 8.77 ms. The signal-to-noise ratio was outstanding in 10/11 patients. In these cases, excellent reliability (Intraclass correlation coefficient, ICC > 0.90 across three different amplitude measurements) was achieved with 10 sample averages. Moreover, our recordings showed very good internal consistency (Cronbach's alpha > 0.95 for 10 epochs). Area-under-the-curve and peak-to-peak measurement proved to be complementary methods for amplitude calculation. Finally, we determined that an optimal derivation requires only two recording electrodes, aligned on a horizontal axis around the laryngeal prominence. In conclusion, we describe here an optimal methodology for the recording of VNS-induced motor evoked responses from the larynx. Although further clinical validation is still necessary, LMEPs might be useful as a non-invasive marker of effective nerve activation, and as an aid for the clinician to perform a more rational titration of VNS parameters.
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Affiliation(s)
- Simone Vespa
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Lars Stumpp
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | | | - Jean Delbeke
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Hugo Smets
- Bio, Electro And Mechanical Systems, Université Libre de Bruxelles, Brussels, Belgium
| | - Joaquin Cury
- Bio, Electro And Mechanical Systems, Université Libre de Bruxelles, Brussels, Belgium
| | - Susana Ferrao Santos
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium.,Centre for Refractory Epilepsy, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Herbert Rooijakkers
- Department of Neurosurgery, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Antoine Nonclercq
- Bio, Electro And Mechanical Systems, Université Libre de Bruxelles, Brussels, Belgium
| | - Robrecht Raedt
- 4Brain, Institute for Neurosciences, Ghent University, Ghent, Belgium
| | - Kristl Vonck
- 4Brain, Institute for Neurosciences, Ghent University, Ghent, Belgium.,Reference Center for Refractory Epilepsy, Department of Neurology, Ghent University, Ghent, Belgium
| | - Riëm El Tahry
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium.,Centre for Refractory Epilepsy, Cliniques Universitaires Saint-Luc, Brussels, Belgium
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Why Does Threshold Level Change in Transcranial Motor-evoked Potentials During Surgery for Supratentorial Lesions? J Neurosurg Anesthesiol 2017; 29:393-399. [DOI: 10.1097/ana.0000000000000336] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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The Percentage of Amplitude Decrease Warning Criteria for Transcranial MEP Monitoring. J Clin Neurophysiol 2017; 34:22-31. [DOI: 10.1097/wnp.0000000000000338] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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Abboud T, Schaper M, Dührsen L, Schwarz C, Schmidt NO, Westphal M, Martens T. A novel threshold criterion in transcranial motor evoked potentials during surgery for gliomas close to the motor pathway. J Neurosurg 2016; 125:795-802. [PMID: 26799297 DOI: 10.3171/2015.8.jns151439] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Warning criteria for monitoring of motor evoked potentials (MEP) after direct cortical stimulation during surgery for supratentorial tumors have been well described. However, little is known about the value of MEP after transcranial electrical stimulation (TES) in predicting postoperative motor deficit when monitoring threshold level. The authors aimed to evaluate the feasibility and value of this method in glioma surgery by using a new approach for interpreting changes in threshold level involving contra- and ipsilateral MEP. METHODS Between November 2013 and December 2014, 93 patients underwent TES-MEP monitoring during resection of gliomas located close to central motor pathways but not involving the primary motor cortex. The MEP were elicited by transcranial repetitive anodal train stimulation. Bilateral MEP were continuously evaluated to assess percentage increase of threshold level (minimum voltage needed to evoke a stable motor response from each of the muscles being monitored) from the baseline set before dural opening. An increase in threshold level on the contralateral side (facial, arm, or leg muscles contralateral to the affected hemisphere) of more than 20% beyond the percentage increase on the ipsilateral side (facial, arm, or leg muscles ipsilateral to the affected hemisphere) was considered a significant alteration. Recorded alterations were subsequently correlated with postoperative neurological deterioration and MRI findings. RESULTS TES-MEP could be elicited in all patients, including those with recurrent glioma (31 patients) and preoperative paresis (20 patients). Five of 73 patients without preoperative paresis showed a significant increase in threshold level, and all of them developed new paresis postoperatively (transient in 4 patients and permanent in 1 patient). Eight of 20 patients with preoperative paresis showed a significant increase in threshold level, and all of them developed postoperative neurological deterioration (transient in 4 patients and permanent in 4 patients). In 80 patients no significant change in threshold level was detected, and none of them showed postoperative neurological deterioration. The specificity and sensitivity in this series were estimated at 100%. Postoperative MRI revealed gross-total tumor resection in 56 of 82 patients (68%) in whom complete tumor resection was attainable; territorial ischemia was detected in 4 patients. CONCLUSIONS The novel threshold criterion has made TES-MEP a useful method for predicting postoperative motor deficit in patients who undergo glioma surgery, and has been feasible in patients with preoperative paresis as well as in patients with recurrent glioma. Including contra- and ipsilateral changes in threshold level has led to a high sensitivity and specificity.
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Affiliation(s)
- Tammam Abboud
- Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Miriam Schaper
- Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Lasse Dührsen
- Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Cindy Schwarz
- Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nils Ole Schmidt
- Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Manfred Westphal
- Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias Martens
- Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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