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Song Y, Surgenor JV, Leeds ZT, Kanter JH, Martinez-Camblor P, Smith WJ, Boone MD, Abess AT, Evans LT, Kobylarz EJ. Variables associated with cortical motor mapping thresholds: A retrospective data review with a unique case of interlimb motor facilitation. Front Neurol 2023; 14:1150670. [PMID: 37114230 PMCID: PMC10128911 DOI: 10.3389/fneur.2023.1150670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 03/15/2023] [Indexed: 04/29/2023] Open
Abstract
Introduction Intraoperative neuromonitoring (IONM) is crucial to preserve eloquent neurological functions during brain tumor resections. We observed a rare interlimb cortical motor facilitation phenomenon in a patient with recurrent high-grade glioma undergoing craniotomy for tumor resection; the patient's upper arm motor evoked potentials (MEPs) increased in amplitude significantly (up to 44.52 times larger, p < 0.001) following stimulation of the ipsilateral posterior tibial nerve at 2.79 Hz. With the facilitation effect, the cortical MEP stimulation threshold was reduced by 6 mA to maintain appropriate continuous motor monitoring. It likely has the benefit of reducing the occurrence of stimulation-induced seizures and other adverse events associated with excessive stimulation. Methods We conducted a retrospective data review including 120 patients who underwent brain tumor resection with IONM at our center from 2018 to 2022. A broad range of variables collected pre-and intraoperatively were reviewed. The review aimed to determine: (1) whether we overlooked this facilitation phenomenon in the past, (2) whether this unique finding is related to any specific demographic information, clinical presentation, stimulation parameter (s) or anesthesia management, and (3) whether it is necessary to develop new techniques (such as facilitation methods) to reduce cortical stimulation intensity during intraoperative functional mapping. Results There is no evidence suggesting that clinical presentation, stimulation configuration, or intraoperative anesthesia management of the patient with the facilitation effect were significantly different from our general patient cohort. Even though we did not identify the same facilitation effect in any of these patients, we were able to determine that stimulation thresholds for motor mapping are significantly associated with the location of stimulation (p = 0.003) and the burst suppression ratio (BSR) (p < 0.001). Stimulation-induced seizures, although infrequent (4.05%), could occur unexpectedly even when the BSR was 70%. Discussion We postulated that functional reorganization and neuronal hyperexcitability induced by glioma progression and repeated surgeries were probable underlying mechanisms of the interlimb facilitation phenomenon. Our retrospective review also provided a practical guide to cortical motor mapping in brain tumor patients under general anesthesia. We also underscored the need for developing new techniques to reduce the stimulation intensity and, hence, seizure occurrence.
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Affiliation(s)
- Yinchen Song
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States
- Geisel School of Medicine, Dartmouth College, Hanover, NH, United States
- *Correspondence: Yinchen Song,
| | - James V. Surgenor
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States
- Haverford College, Haverford, PA, United States
| | - Zachary T. Leeds
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States
| | - John H. Kanter
- Section of Neurosurgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States
| | - Pablo Martinez-Camblor
- Department of Anesthesiology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States
- Department of Biomedical Data Science, Geisel School of Medicine, Dartmouth College, Hanover, NH, United States
| | - William J. Smith
- Geisel School of Medicine, Dartmouth College, Hanover, NH, United States
| | - M. Dustin Boone
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States
- Geisel School of Medicine, Dartmouth College, Hanover, NH, United States
- Department of Anesthesiology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States
| | - Alexander T. Abess
- Geisel School of Medicine, Dartmouth College, Hanover, NH, United States
- Department of Anesthesiology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States
| | - Linton T. Evans
- Geisel School of Medicine, Dartmouth College, Hanover, NH, United States
- Section of Neurosurgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States
| | - Erik J. Kobylarz
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States
- Geisel School of Medicine, Dartmouth College, Hanover, NH, United States
- Thayer School of Engineering, Dartmouth College, Hanover, NH, United States
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Simon MV, Nuwer MR, Szelényi A. Electroencephalography, electrocorticography, and cortical stimulation techniques. HANDBOOK OF CLINICAL NEUROLOGY 2022; 186:11-38. [PMID: 35772881 DOI: 10.1016/b978-0-12-819826-1.00001-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Electroencephalography (EEG) and electrocorticography (ECoG) are two important neurophysiologic techniques used in the operating room for monitoring and mapping electrical brain activity. In this chapter, we detail their principle, recording methodology, and address specifics of their interpretation in the intraoperative setting (e.g., effect of anesthetics), as well as their clinical applications in epilepsy and non-epilepsy surgeries. In addition, we address differences between scalp, surface, and deep cortical recordings that will help towards a more reliable interpretation of the significance of electrophysiologic parameters such as amplitude and morphology as well as in differentiation between abnormal and normal patterns of electrical brain activity. Electrical stimulation is used for intraoperative mapping of different cortical functions such as language, parietal, and motor. Stimulation paradigms used in clinical practice vary with regard to stimulation frequencies and probes being used. Parameters, such as the number of phases per pulse, pulse/phase duration, pulse frequency, organization, and polarity, define their characteristics, including their safety, propensity to trigger seizures, efficiency and reliability of stimulation, and the mapping thresholds. Specifically, in this chapter, we will address differences between monopolar and bipolar stimulation; anodal and cathodal polarity; monophasic and biphasic pulses; constant voltage, and constant current paradigms.
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Affiliation(s)
- Mirela V Simon
- Department of Neurology, Massachusetts General Hospital, Boston, MA, United States.
| | - Marc R Nuwer
- Departments of Neurology and Clinical Neurophysiology, David Geffen School of Medicine, University of California Los Angeles, and Ronald Reagan UCLA Medical Center, Los Angeles, CA, United States
| | - Andrea Szelényi
- Department of Neurosurgery, University Hospital, Ludwig-Maximilians-University (LMU), Munich, Germany
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Roux F, Niare M, Charni S, Giussani C, Durand J. Functional architecture of the motor homunculus detected by electrostimulation. J Physiol 2020; 598:5487-5504. [DOI: 10.1113/jp280156] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 08/21/2020] [Indexed: 11/08/2022] Open
Affiliation(s)
- Franck‐Emmanuel Roux
- CNRS (CERCO) UMR Unité 5549 Université Paul Sabatier Toulouse France
- Pôle Neurosciences (Neurochirurgie) Centres Hospitalo‐Universitaires Toulouse France
| | - Mahamadou Niare
- CNRS (CERCO) UMR Unité 5549 Université Paul Sabatier Toulouse France
- Pôle Neurosciences (Neurochirurgie) Centres Hospitalo‐Universitaires Toulouse France
| | - Saloua Charni
- CNRS (CERCO) UMR Unité 5549 Université Paul Sabatier Toulouse France
- Pôle Neurosciences (Neurochirurgie) Centres Hospitalo‐Universitaires Toulouse France
| | - Carlo Giussani
- Neurosurgery School of Medicine Ospedale San Gerardo Università degli Studi di Milano Bicocca Monza Italy
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Irwin MG, Chung CKE, Ip KY, Wiles MD. Influence of propofol-based total intravenous anaesthesia on peri-operative outcome measures: a narrative review. Anaesthesia 2020; 75 Suppl 1:e90-e100. [PMID: 31903578 DOI: 10.1111/anae.14905] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2019] [Indexed: 12/12/2022]
Abstract
Propofol-based total intravenous anaesthesia is well known for its smooth, clear-headed recovery and anti-emetic properties, but there are also many lesser known beneficial properties that can potentially influence surgical outcome. We will discuss the anti-oxidant, anti-inflammatory and immunomodulatory effects of propofol and their roles in pain, organ protection and immunity. We will also discuss the use of propofol in cancer surgery, neurosurgery and older patients.
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Affiliation(s)
- M G Irwin
- Department of Anaesthesiology, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - C K E Chung
- Department of Anaesthesiology, Queen Mary Hospital, Hong Kong Special Administrative Region, China
| | - K Y Ip
- Department of Anaesthesiology, Queen Mary Hospital, Hong Kong Special Administrative Region, China
| | - M D Wiles
- Department of Anaesthesia, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
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Dineen J, Maus DC, Muzyka I, See RB, Cahill DP, Carter BS, Curry WT, Jones PS, Nahed BV, Peterfreund RA, Simon MV. Factors that modify the risk of intraoperative seizures triggered by electrical stimulation during supratentorial functional mapping. Clin Neurophysiol 2019; 130:1058-1065. [DOI: 10.1016/j.clinph.2019.03.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 02/05/2019] [Accepted: 03/13/2019] [Indexed: 12/19/2022]
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Corticobulbar motor evoked potentials from tongue muscles used as a control in cervical spinal surgery. Clin Neurophysiol Pract 2017; 2:124-129. [PMID: 30214984 PMCID: PMC6123852 DOI: 10.1016/j.cnp.2017.05.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 05/03/2017] [Accepted: 05/20/2017] [Indexed: 11/22/2022] Open
Abstract
Objective Motor evoked potentials (MEPs) changes might be caused to the non-surgically induced factors during cervical spinal surgery. Therefore, control MEPs recorded cranially to the exit of the C5 root are highly recommendable in cervical spinal surgery. We studied whether corticobulbar MEPs (C-MEPs) from tongue muscle could be used as a control MEPs in cervical spinal surgery. Methods Twenty-five consecutive cervical spinal surgeries were analyzed. Stimulation of motor area for tongue was done by subcutaneous electrodes placed at C3/C4 (10-20 EEG System), and recording was done from both sides of tongue. Results C-MEPs were recorded successfully 24 out of the 25 (96%) tested patients. Forty-six out of fifty MEPs (92%) from tongue muscles were monitorable from the baseline. In two patients, we could obtain only unilateral C-MEPs. Mean MEPs latencies obtained from the left and right side of the tongue were 11.5 ± 1 ms and 11.5 ± 0.8 ms, respectively. Conclusions Monitoring C-MEPs from tongue muscles might be useful control in cervical spinal surgery. They were easily elicited and relatively free from phenomenon of peripheral stimulation of the hypoglossal nerves. Significance This is first study to identify the usefulness of C-MEPs as a control of cervical spinal surgery.
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Moldovan M, Calin A, Kumaraswamy VM, Braver D, Simon MV. Burst-Suppression Ratio on Electrocorticography Depends on Interelectrode Distance. J Clin Neurophysiol 2017; 33:127-32. [PMID: 26690549 DOI: 10.1097/wnp.0000000000000248] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
INTRODUCTION With deepening of anesthesia-induced comatose states, the EEG becomes fragmented by increasing periods of suppression. When measured from conventional EEG recordings, the binary burst-suppression signal (BS) appears similar across the scalp. As such, the BS ratio (BSR), quantifying the fraction of time spent in suppression, is clinically considered a global index of brain function in sedation monitoring. Recent studies indicate that BS may be considerably asynchronous when measured with higher spatial resolution such as on electrocorticography. The authors investigated the magnitude of BSR changes with cortical recording interelectrode distance. METHODS The authors selected fronto-parietal electrocorticography recordings showing propofol-induced BS recorded via 8-electrode strips (1-cm interelectrode distance) during cortical motor mapping in 31 patients. For 1-minute epochs, bipolar recordings were computed between each electrode pair. The median BSR, burst duration (BD), and bursting frequency were derived for each interelectrode distance. RESULTS At 1-cm interelectrode distance, with increasing BSR, BD decreased exponentially. For a BSR between 50% and 80%, BD reached a plateau of 2.1 seconds while the bursting frequency decreased from 14 to 6 bursts per minute. With increasing interelectrode distance, BD increased at a rate of 0.2 seconds per cm. This correlated with a decrease in BSR with distance that reached the rate of -4.4 percentage per centimeters during deepest anesthesia. CONCLUSIONS With increasing cortical interelectrode recording distance, burst summation leads to an increasing BD associated with a reduction in BSR. Standardization of interelectrode distance is important for cortical BSR measurements.
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Affiliation(s)
- Mihai Moldovan
- *Division of Physiology and Neuroscience, Department of Functional Sciences, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania; †Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark; ‡Intraoperative Neurophysiology Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; §Department of Pharmacology, University of Oxford, Oxford, United Kingdom; and ‖Department of Neurology, University Hospitals Case Medical Center, Cleveland, Ohio
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Simon MV, Sheth SA, Eckhardt CA, Kilbride RD, Braver D, Williams Z, Curry W, Cahill D, Eskandar EN. Phase reversal technique decreases cortical stimulation time during motor mapping. J Clin Neurosci 2014; 21:1011-7. [DOI: 10.1016/j.jocn.2013.12.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 12/18/2013] [Indexed: 10/25/2022]
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Intraoperative Somatosensory Evoked Potential Monitoring Decreases EEG Burst Suppression Ratio During Deep General Anesthesia. J Clin Neurophysiol 2014; 31:133-7. [DOI: 10.1097/wnp.0000000000000034] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Intraoperative Neurophysiologic Sensorimotor Mapping and Monitoring in Supratentorial Surgery. J Clin Neurophysiol 2013; 30:571-90. [DOI: 10.1097/01.wnp.0000436897.02502.78] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Macdonald DB, Skinner S, Shils J, Yingling C. Intraoperative motor evoked potential monitoring - a position statement by the American Society of Neurophysiological Monitoring. Clin Neurophysiol 2013; 124:2291-316. [PMID: 24055297 DOI: 10.1016/j.clinph.2013.07.025] [Citation(s) in RCA: 302] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 07/20/2013] [Accepted: 07/22/2013] [Indexed: 12/12/2022]
Abstract
The following intraoperative MEP recommendations can be made on the basis of current evidence and expert opinion: (1) Acquisition and interpretation should be done by qualified personnel. (2) The methods are sufficiently safe using appropriate precautions. (3) MEPs are an established practice option for cortical and subcortical mapping and for monitoring during surgeries risking motor injury in the brain, brainstem, spinal cord or facial nerve. (4) Intravenous anesthesia usually consisting of propofol and opioid is optimal for muscle MEPs. (5) Interpretation should consider limitations and confounding factors. (6) D-wave warning criteria consider amplitude reduction having no confounding factor explanation: >50% for intramedullary spinal cord tumor surgery, and >30-40% for peri-Rolandic surgery. (7) Muscle MEP warning criteria are tailored to the type of surgery and based on deterioration clearly exceeding variability with no confounding factor explanation. Disappearance is always a major criterion. Marked amplitude reduction, acute threshold elevation or morphology simplification could be additional minor or moderate spinal cord monitoring criteria depending on the type of surgery and the program's technique and experience. Major criteria for supratentorial, brainstem or facial nerve monitoring include >50% amplitude reduction when warranted by sufficient preceding response stability. Future advances could modify these recommendations.
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Affiliation(s)
- D B Macdonald
- Section of Clinical Neurophysiology, Department of Neurosciences, King Faisal Specialist Hospital & Research Center, MBC 76, PO Box 3354, Riyadh, Saudi Arabia.
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Sheth SA, Eckhardt CA, Walcott BP, Eskandar EN, Simon MV. Factors Affecting Successful Localization of the Central Sulcus Using the Somatosensory Evoked Potential Phase Reversal Technique. Neurosurgery 2013; 72:828-34; discussion 834. [DOI: 10.1227/neu.0b013e3182897447] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
BACKGROUND:
Perirolandic surgery is associated with an increased risk of postoperative neurological deficit that can be reduced by accurate recognition of the location of sensorimotor cortex. The median somatosensory evoked potential (MSSEP) phase reversal technique (PRT) reliably identifies the central sulcus (CS) intraoperatively, but does require additional surgical time. Awareness of factors that lengthen the time required for MSSEP PRT has important implications for surgical planning.
OBJECTIVE:
To identify factors that affect the time required for CS localization via MSSEP PRT.
METHODS:
Multivariate Cox regression analysis, applied in 100 consecutive cases of perirolandic surgery at a single institution from 2005 to 2010, during which CS localization was attempted via a standardized MSSEP PRT.
RESULTS:
The CS was reliably identified in 77 cases. The mean time to identification was 5 minutes (SD = 5; range, 1–20 minutes). Lesion location either very close to the CS (within the postcentral gyrus) or at an intermediate distance (with edema extending very close to the CS) independently decreased the rate at which the CS was identified by 73% (hazard ratio: 0.27, P < .001) and 55% (hazard ratio: 0.45, P = .007), respectively. Highly destructive pathology reduced this rate by 42% (hazard ratio: 0.58, P = .03), after adjusting for other important factors. Epidural recording, age, and the presence of a burst suppression pattern on the electroencephalogram had no effect.
CONCLUSION:
MSSEP PRT is an effective method for CS identification and only marginally lengthens the operative time. However, difficulty in CS localization can be expected in the presence of postcentral gyrus lesions, edema distorting perirolandic anatomy, and with highly destructive pathology.
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Affiliation(s)
| | | | | | | | - Mirela V. Simon
- Departments of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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Risk of seizures during intraoperative electrocortical stimulation of brain motor areas: a retrospective study on 50 patients. Neurol Sci 2012; 34:63-70. [PMID: 22350148 DOI: 10.1007/s10072-012-0968-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 01/27/2012] [Indexed: 10/28/2022]
Abstract
Tumours close to cerebral cortices involved in motor and language functions represent a major challenge for neurosurgeons. Intraoperative neurophysiologic monitoring is useful to gain insight into the anatomy of and the relationship between pathological and normal tissues. In this study we report on the experience of electrocortical stimulation in the surgery of tumours adjacent to the motor cortex in 50 patients under general anaesthesia (26 under propofol, 24 under sevoflurane), and on EMG responses from contralateral muscles. In 18 patients stimulation evoked seizures, which were controlled only with antiepileptic drugs (36%). No difference was found in the incidence of intra-operative seizures between the patients with (10 out of 27) or without (8 out of 23) pre-operative epilepsy (p = 0.8685). The majority of the patients (13 out of 18) with intraoperative seizures were under sevoflurane (p = 0.01) and there was a statistically significant difference in the mean electrical intensity used between the two groups, sevoflurane and propofol, respectively 5.3 ± 1.3 mA and 3.6 ± 2 mA (p = 0.03). Regarding pre-operative anti-epileptic drugs, the use of levitiracetam was associated with a high incidence of intraoperative seizure (5 out of 6 patients). 4 patients developed new, unwanted, permanent neurological deficits, of which 2 had intraoperative seizures controlled only with antiepileptic drugs. Electrocortical stimulation is a powerful tool to understand the functional organization of patients' eloquent areas. Intraoperative epileptic seizures may represent an unwanted complication preventing further stimulation and possibly worsening neurological results. The choice of anaesthetics according to the patients' characteristics, pre-op symptoms and medical therapy is pivotal.
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The variability of stimulus thresholds in electrophysiologic cortical language mapping. J Clin Neurophysiol 2011; 28:210-6. [PMID: 21399523 DOI: 10.1097/wnp.0b013e3182121827] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The aim of this study was to investigate the variability of electrical stimulation threshold in cortical language mapping in relationship to the lobar location of the mapped eloquent cortex and the distance between the latter and the location of the cortical lesion. A multivariate linear regression analysis was performed in a sample of 39 patients who underwent standardized successful language cortical mapping. Estimated stimulus threshold for temporal language cortex was 1.45 times higher than the estimated threshold for frontal language cortex, after adjusting for the other variables (P = 0.017). Stimulation of the mapped cortex in close proximity to the lesion or to the lesional edema increased the estimated threshold 2.6 or 1.8 times, respectively, compared with stimulation in other areas, after adjusting for the other variables (P < 0.0001, P = 0.0017). In concordance with prior findings, our results show that stimulus threshold in cortical language mapping is dependent on the lobar location of the mapped cortex. In addition, stimulus threshold is increased when the mapped cortex is in close proximity to the location of the lesion or perilesional edema.
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Jahangiri FR, Sherman JH, Sheehan J, Shaffrey M, Dumont AS, Vengrow M, Vega-Bermudez F. Limiting the Current Density During Localization of the Primary Motor Cortex by Using a Tangential-Radial Cortical Somatosensory Evoked Potentials Model, Direct Electrical Cortical Stimulation, and Electrocorticography. Neurosurgery 2011; 69:893-8. [DOI: 10.1227/neu.0b013e3182230ac3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
BACKGROUND:
Traditionally, the dual-radial model, which requires high cortical stimulation intensities and may evoke intraoperative seizures, is used for mapping during resection of lesions within or near the central sulcus.
OBJECTIVE:
To examine the potential utility of using the multimodal tangential-radial triphasic model, which may increase the accuracy and reliability of cortical mapping at lower stimulation intensities.
METHODS:
We performed a retrospective review of intracranial neuromonitoring cases at the University of Virginia. The tangential-radial triphasic model used direct electrical cortical stimulation (DECS), electrocorticography, and somatosensory evoked potentials with an additional P25 peak for waveform interpretation, instead of the older dual-radial model with N20 and P30 peaks alone. The central sulcus and sensory cortex were localized by generating multiple sensory maps. DECS with 50-Hz frequency was applied. Electrocorticography was used for detection of afterdischarges.
RESULTS:
Fifteen consecutive intracranial cases were identified. The patients consisted of 8 males and 7 females ranging in age from 12 to 74 years (median, 53 years). Fourteen patients had an intra-axial cortical mass, and 1 patient had a cortical arteriovenous malformation. The DECS thresholds ranged from 3.7 to 12 mA (median, 6.2 mA). Localization of motor and sensory cortices was accurately performed at low thresholds with bipolar DECS in all patients. Intraoperative seizures occurred in 1 patient (7%), and new permanent postoperative functional deficits occurred in 1 patient (7%).
CONCLUSION:
Our mapping technique appears safe and reliable for resection near the central sulcus. The tangential-radial triphasic model allows for lower stimulation intensities, reducing the risk of intraoperative seizures.
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Affiliation(s)
| | - Jonathan H Sherman
- Department of Neurosurgery, University of Virginia Medical Center, Charlottesville, Virginia
| | - Jason Sheehan
- Department of Neurosurgery, University of Virginia Medical Center, Charlottesville, Virginia
| | - Mark Shaffrey
- Department of Neurosurgery, University of Virginia Medical Center, Charlottesville, Virginia
| | - Aaron S Dumont
- Department of Neurosurgery, University of Virginia Medical Center, Charlottesville, Virginia
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Bibliography. Ambulatory anesthesia. Current world literature. Curr Opin Anaesthesiol 2010; 23:778-80. [PMID: 21051960 DOI: 10.1097/aco.0b013e3283415829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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