Feasibility of intraoperative motor evoked potential monitoring during tethered cord surgery in infants younger than 12 months

Abstract Purpose Feasibility, reliability, and safety assessment of transcranial motor evoked potentials (MEPs) in infants less than 12 months of age. Methods A total of 22 patients with a mean age of 33 (range 13–49) weeks that underwent neurosurgery for tethered cord were investigated. Data from intraoperative MEPs, anesthesia protocols, and clinical records were reviewed. Anesthesia during surgery was maintained by total intravenous anesthesia (TIVA). Results MEPs were present in all patients for the upper extremities and in 21 out of 22 infants for the lower extremities. Mean baseline stimulation intensity was 101 ± 20 mA. If MEPs were present at the end of surgery, no new motor deficit occurred. In the only case of MEP loss, preoperative paresis was present, and high baseline intensity thresholds were needed. MEP monitoring did not lead to any complications. TIVA was maintained with an average propofol infusion rate of 123.5 ± 38.2 µg/kg/min and 0.46 ± 0.17 µg/kg/min for remifentanil. Conclusion In spinal cord release surgery, the use of intraoperative MEP monitoring is indicated regardless of the patient’s age. We could demonstrate the feasibility and safety of MEP monitoring in infants if an adequate anesthetic regimen is applied. More data is needed to verify whether an irreversible loss of robust MEPs leads to motor deficits in this young age group.

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Long-term motor deficit in brain tumour surgery with preserved intra-operative motor-evoked potentials

Brain Communications ◽

10.1093/braincomms/fcaa226 ◽

2021 ◽

Vol 3 (1) ◽

Author(s):

Davide Giampiccolo ◽

Cristiano Parisi ◽

Pietro Meneghelli ◽

Vincenzo Tramontano ◽

Federica Basaldella ◽

...

Keyword(s):

Evoked Potentials ◽

Brain Tumour ◽

Evoked Potential ◽

Corticospinal Tract ◽

Motor Evoked Potentials ◽

Motor Evoked Potential ◽

Motor Deficit ◽

Motor Deficits ◽

Brain Tumour Surgery

Abstract Muscle motor-evoked potentials are commonly monitored during brain tumour surgery in motor areas, as these are assumed to reflect the integrity of descending motor pathways, including the corticospinal tract. However, while the loss of muscle motor-evoked potentials at the end of surgery is associated with long-term motor deficits (muscle motor-evoked potential-related deficits), there is increasing evidence that motor deficit can occur despite no change in muscle motor-evoked potentials (muscle motor-evoked potential-unrelated deficits), particularly after surgery of non-primary regions involved in motor control. In this study, we aimed to investigate the incidence of muscle motor-evoked potential-unrelated deficits and to identify the associated brain regions. We retrospectively reviewed 125 consecutive patients who underwent surgery for peri-Rolandic lesions using intra-operative neurophysiological monitoring. Intraoperative changes in muscle motor-evoked potentials were correlated with motor outcome, assessed by the Medical Research Council scale. We performed voxel–lesion–symptom mapping to identify which resected regions were associated with short- and long-term muscle motor-evoked potential-associated motor deficits. Muscle motor-evoked potentials reductions significantly predicted long-term motor deficits. However, in more than half of the patients who experienced long-term deficits (12/22 patients), no muscle motor-evoked potential reduction was reported during surgery. Lesion analysis showed that muscle motor-evoked potential-related long-term motor deficits were associated with direct or ischaemic damage to the corticospinal tract, whereas muscle motor-evoked potential-unrelated deficits occurred when supplementary motor areas were resected in conjunction with dorsal premotor regions and the anterior cingulate. Our results indicate that long-term motor deficits unrelated to the corticospinal tract can occur more often than currently reported. As these deficits cannot be predicted by muscle motor-evoked potentials, a combination of awake and/or novel asleep techniques other than muscle motor-evoked potentials monitoring should be implemented.

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Clinical feasibility and safety of transoesophageal motor-evoked potential monitoring

European Journal of Cardio-Thoracic Surgery ◽

10.1093/ejcts/ezaa002 ◽

2020 ◽

Vol 57 (6) ◽

pp. 1076-1082 ◽

Cited By ~ 2

Author(s):

Norihiko Shiiya ◽

Kazumasa Tsuda ◽

Ken Yamanaka ◽

Daisuke Takahashi ◽

Naoki Washiyama ◽

...

Keyword(s):

Evoked Potential ◽

Spinal Cord Injuries ◽

Motor Evoked Potentials ◽

False Positive Rate ◽

Large Diameter ◽

Motor Evoked Potential ◽

Monitoring Methods ◽

Evoked Potential Monitoring ◽

Transcranial Motor Evoked Potentials ◽

Potential Monitoring

Abstract OBJECTIVES Canine experiments have shown that transoesophageal motor-evoked potential monitoring is feasible, safe and stable, with a quicker response to ischaemia and a better prognostic value than transcranial motor-evoked potentials. We aimed to elucidate whether or not these findings were clinically reproducible. METHODS A bipolar oesophageal electrode mounted on a large-diameter silicon tube and a train of 5 biphasic wave stimuli were used for transoesophageal stimulation. Results of 18 patients (median age 74.5 years, 13 males) were analysed. RESULTS There were no mortalities, spinal cord injuries or complications related with transoesophageal stimulation. Transcranial motor-evoked potential could not be monitored up to the end of surgery in 3 patients for unknown reasons, 2 of whom from the beginning. Transoesophageal motor-evoked potential became non-evocable after manipulation of a transoesophageal echo probe in 2 patients. Strenuous movement of the upper limbs during transoesophageal stimulation was observed in 3 patients. In 14 patients who successfully completed both monitoring methods up to the end of surgery (11 thoraco-abdominal and 3 descending aortic repair), the final results were judged as false positives in 6 by transcranial stimulation and in 1 by transoesophageal stimulation. The stimulation intensity was significantly lower and the upper limb amplitude was significantly higher by transoesophageal stimulation, while the lower limb amplitude was comparable. CONCLUSIONS Transoesophageal motor-evoked potential monitoring is clinically feasible and safe with a low false positive rate. A better electrode design is required to avoid its migration by transoesophageal echo manipulation. Further studies may be warranted. Clinical registration number UMIN000022320.

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Detection of acute femoral artery ischemia during neuroembolization by somatosensory and motor evoked potential monitoring

Interventional Neuroradiology ◽

10.1177/1591019915583219 ◽

2015 ◽

Vol 21 (3) ◽

pp. 397-400 ◽

Cited By ~ 1

Author(s):

David Purger ◽

Abdullah H Feroze ◽

Omar Choudhri ◽

Leslie Lee ◽

Jaime Lopez ◽

...

Keyword(s):

Evoked Potentials ◽

Motor Evoked Potentials ◽

Motor Evoked Potential ◽

Postoperative Outcome ◽

Limb Ischemia ◽

Peripheral Ischemia ◽

Increased Risk ◽

Evoked Potential Monitoring ◽

Transcranial Motor Evoked Potentials ◽

The Right

Neuromonitoring can be used to map out particular neuroanatomical tracts, define physiologic deficits secondary to specific pathology or intervention, or predict postoperative outcome and proves essential in the detection of central and peripheral ischemic events during neurosurgical intervention. Herein, we describe an instance of elective balloon-assisted coiling of a recurrent basilar tip aneurysm in a 61-year-old woman, where intraoperative somatosensory evoked potentials (SSEPs) and transcranial motor evoked potentials (TcMEPs) were lost in the right lower extremity intraoperatively. We aim to highlight that targeted use of monitoring proves advantageous in both the open surgical and endovascular setting, even in the avoidance of potential iatrogenic peripheral nerve damage and limb ischemia as documented herein. Consideration of the increased risk for peripheral ischemia in the neurointerventional setting is especially imperative in particular populations where blood vessels might be of diminished size, such as in infants, young children, and severely deconditioned adults.

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Motor-evoked potential monitoring for intramedullary spinal cord tumor surgery: correlation of clinical and neurophysiological data in a series of 100 consecutive procedures

Neurosurgical FOCUS ◽

10.3171/foc.1998.4.5.4 ◽

1998 ◽

Vol 4 (5) ◽

pp. E3 ◽

Cited By ~ 188

Author(s):

Karl F. Kothbauer ◽

Vedran Deletis ◽

Fred J. Epstein

Keyword(s):

Spinal Cord ◽

Evoked Potential ◽

Spinal Cord Tumor ◽

Motor Evoked Potential ◽

Motor Deficit ◽

Motor Deficits ◽

Intramedullary Tumors ◽

Intramedullary Spinal Cord ◽

Motor Pathways ◽

Evoked Potential Monitoring

Resection of intramedullary spinal cord tumors carries a high risk for surgical damage to the motor pathways. This surgery is therefore optimal for testing the performance of intraoperative motor evoked potential (MEP) monitoring. This report attempts to provide evidence for the accurate representation of patients' pre- and postoperative motor status by combined epidural and muscle MEP monitoring during intramedullary surgery. The authors used transcranial electrical motor cortex stimulation to elicit MEPs, which were recorded from the spinal cord (with an epidural electrode) and from limb target muscles (thenar, anterior tibial) with needle electrodes. The amplitude of the epidural MEPs and the presence or absence of muscle MEPs were the parameters for MEP interpretation. A retrospective analysis was performed on data from the resection of 100 consecutive intramedullary tumors and MEP data were compared with the pre- and postoperative motor status. Intraoperative monitoring was feasible in all patients without severe preoperative motor deficits. Preoperatively paraplegic patients had no recordable MEPs. The sensitivity of muscle MEPs to detect postoperative motor deficits was 100% and its specificity was 91%. There was no instance in which a patient with stable MEPs developed a motor deficit postoperatively. Intraoperative MEPs adequately represented the motor status of patients undergoing surgery for intramedullary tumors. Because deterioration of the motor status was transient in all cases, it can be considered that impairment of the functional integrity of the motor pathways was detected before permanent deficits occurred.

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Many Intraoperative Monitoring Modalities Have Been Developed To Limit Injury During Extreme Lateral Interbody Fusion (XLIF/MIS XLIF): Does That Mean XLIF/MIS XLIF Are Unsafe?

Surgical Neurology International ◽

10.25259/sni_563_2019 ◽

2019 ◽

Vol 10 ◽

pp. 233

Author(s):

Nancy E. Epstein

Keyword(s):

Motor Evoked Potentials ◽

Degenerative Spondylolisthesis ◽

Motor Evoked Potential ◽

Muscle Relaxants ◽

Neurological Deficits ◽

Motor Deficits ◽

Evoked Potential Monitoring ◽

Neurological Injuries ◽

Lateral Interbody ◽

Neural Monitoring

Background: Extreme lateral interbody fusions (XLIF) and Minimally Invasive (MIS) XLIF pose significant risks of neural injury to the; lumbar plexus, ilioinguinal, iliohypogastric, genitofemoral, lateral femoral cutaneous, and subcostal nerves. To limit these injuries, many intraoperative neural monitoring (IONM) modalities have been proposed. Methods: Multiple studies document various frequencies of neural injuries occurring during MIS XLIF/XLIF: plexus injuries (13.28%); sensory deficits (0-75%; permanent 62.5%); motor deficits (0.7-33.6%; most typically iliopsoas weakness (14.3%-31%)), and anterior thigh/groin pain (12.5-25%.-34%). To avoid/limit these injuries, multiple IONM techniques have been proposed. These include; using finger electrodes during operative dissection, employing motor evoked potentials (MEP), eliminating (no) muscle relaxants (NMR), and using “triggered” EMGs. Results: In one study, finger electrodes for XLIF at L4-L5 level for degenerative spondylolisthesis reduced transient postoperative neurological symptoms from 7 [38%] of 18 cases (e.g. without IONM) to 5 [14%] of 36 cases (with IONM). Two series showed that motor evoked potential monitoring (MEP) for XLIF reduced postoperative motor deficits; they, therefore, recommended their routine use for XLIF. Another study demonstrated that eliminating muscle relaxants during XLIF markedly reduced postoperative neurological deficits/thigh pain by allowing for better continuous EMG monitoring (e.g. NMR no muscle relaxants). Finally, a “triggered” EMG study” reduced postoperative motor neuropraxia, largely by limiting retraction time. Conclusion: Multiple studies have offered different IONM techniques to avert neurological injuries following MIS XLIF/XLIF. Does this mean that these procedures (e.g. XLIF/MIS XLIF) are unsafe?

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Motor Evoked Potential Warning Criteria in Supratentorial Surgery: A Scoping Review

Cancers ◽

10.3390/cancers13112803 ◽

2021 ◽

Vol 13 (11) ◽

pp. 2803

Author(s):

Evridiki Asimakidou ◽

Pablo Alvarez Abut ◽

Andreas Raabe ◽

Kathleen Seidel

Keyword(s):

Scoping Review ◽

Predictive Value ◽

Motor Evoked Potentials ◽

Motor Evoked Potential ◽

Critical Duration ◽

Motor Deficit ◽

Warning Sign ◽

Outcome Reporting ◽

Scoping Reviews ◽

Warning Criteria

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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Impact of anesthesia on transcranial electric motor evoked potential monitoring during spine surgery: a review of the literature

Neurosurgical FOCUS ◽

10.3171/2009.8.focus09145 ◽

2009 ◽

Vol 27 (4) ◽

pp. E7 ◽

Cited By ~ 50

Author(s):

Anthony C. Wang ◽

Khoi D. Than ◽

Arnold B. Etame ◽

Frank La Marca ◽

Paul Park

Keyword(s):

Spine Surgery ◽

Evoked Potential ◽

Motor Evoked Potential ◽

Neurological Injury ◽

Neurophysiological Monitoring ◽

Intravenous Anesthesia ◽

Inhalational Anesthetics ◽

Anesthetic Agents ◽

Evoked Potential Monitoring ◽

The Impact

Object Transcranial motor evoked potential (TcMEP) monitoring is frequently used in complex spinal surgeries to prevent neurological injury. Anesthesia, however, can significantly affect the reliability of TcMEP monitoring. Understanding the impact of various anesthetic agents on neurophysiological monitoring is therefore essential. Methods A literature search of the National Library of Medicine database was conducted to identify articles pertaining to anesthesia and TcMEP monitoring during spine surgery. Twenty studies were selected and reviewed. Results Inhalational anesthetics and neuromuscular blockade have been shown to limit the ability of TcMEP monitoring to detect significant changes. Hypothermia can also negatively affect monitoring. Opioids, however, have little influence on TcMEPs. Total intravenous anesthesia regimens can minimize the need for inhalational anesthetics. Conclusions In general, selecting the appropriate anesthetic regimen with maintenance of a stable concentration of inhalational or intravenous anesthetics optimizes TcMEP monitoring.

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Intraoperative vascular complications during 2278 cerebral endovascular procedures with multimodality IONM: relationship between signal change, complication, intervention and postoperative outcome

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2020-016604 ◽

2020 ◽

pp. neurintsurg-2020-016604

Author(s):

W Bryan Wilent ◽

Olga Belyakina ◽

Eric Korsgaard ◽

Stavropoula I Tjoumakaris ◽

M Reid Gooch ◽

...

Keyword(s):

Endovascular Procedures ◽

Motor Evoked Potentials ◽

Vascular Complications ◽

Postoperative Outcome ◽

Complete Loss ◽

Motor Deficit ◽

Motor Deficits ◽

Likelihood Ratios ◽

Arterial Complication ◽

The Impact

BackgroundIntraoperative neuromonitoring (IONM) is often used during cerebral endovascular procedures.ObjectiveTo investigate the relationship between intraoperative vascular complications and IONM signal changes, and the impact of interventions on signal resolution and postoperative outcomes.MethodsA series of 2278 cerebral endovascular procedures conducted under general anesthesia and using electroencephalography and somatosensory evoked potential monitoring were retrospectively reviewed. A subset of 763 procedures also included motor evoked potentials (MEPs). IONM alerts were categorized as either a partial attenuation or complete loss of signal. Vascular complications were subcategorized as due to rupture, emboli, instrumentation, or vasospasm. Odds ratios (ORs) for new postoperative motor deficits were calculated and diagnostic accuracy was measured using sensitivity, specificity, and likelihood ratios.ResultsThe overall incidence of new postoperative motor deficit was 1.2%; 20.4% in cases with an IONM alert and 0.09% in cases without an alert. Relative to procedures with no alerts, odds of a new deficit increased if there was partial signal attenuation (OR=210.9, 95% CI 44.3 to 1003.5, p<0.0001) and increased further with complete loss of signal (OR=1437.3, 95% CI 297.3 to 6948.2, p<0.0001). Relative to procedures with unresolved alerts, odds of a new deficit decreased if the alert was fully resolved (OR=0.039, 95% CI 0.005 to 0.306, p<0.002). Procedures using MEPs had slightly higher sensitivity (92.3% vs 85.7%) but slightly lower specificity (96.7% vs 98.2%).ConclusionsAn IONM alert associated with an arterial complication is associated with a dramatic increase in odds of a new postoperative deficit; however, if there is resolution of the alert prior to closure, odds of a new deficit decrease significantly.

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