No abstract available.
Cerebellopontine Angle* ; Intraoperative Neurophysiological Monitoring* ; Neuroma, Acoustic*

BACKGROUND: Intraoperative monitoring during carotid endarterectomy is crucial for cerebral protection. We investigated the results of carotid endarterectomy under dual monitoring with stump pressure and electroencephalography. METHODS: We retrospectively reviewed the medical records of 50 patients who underwent carotid endarterectomy between March 2010 and February 2016. We inserted a temporary shunt if the stump pressure was lower than 35 mm Hg or if any intraoperative change was observed on electroencephalography. RESULTS: Seventeen (34%) patients used a temporary shunt, and the mean stump pressure was 26.8 mm Hg in the shunt group and 46.5 mm Hg in the non-shunt group. No postoperative mortality or bleeding occurred. Postoperatively, there were 3 cases (6%) of minor stroke, all of which took place in the shunt group. A comparison of the preoperative and the intraoperative characteristics of the shunt group with those of the non-shunt group revealed no statistically significant difference between the 2 groups (p <0.01). CONCLUSION: Dual monitoring with stump pressure and electroencephalography was found to be a safe and reliable monitoring method with results comparable to those obtained using single monitoring. Further study should be performed to investigate the precise role of each monitoring method.
Carotid Artery Diseases ; Electroencephalography* ; Endarterectomy, Carotid* ; Hemorrhage ; Humans ; Intraoperative Neurophysiological Monitoring ; Medical Records ; Methods ; Monitoring, Intraoperative ; Mortality ; Retrospective Studies ; Stroke

BACKGROUND AND PURPOSE: We aimed to determine the effectiveness of intraoperative neurophysiological monitoring focused on the transcranial motor-evoked potential (MEP) in patients with medically refractory temporal lobe epilepsy (TLE). METHODS: We compared postoperative neurological deficits in patients who underwent TLE surgery with or without transcranial MEPs combined with somatosensory evoked potential (SSEP) monitoring between January 1995 and June 2018. Transcranial motor stimulation was performed using subdermal electrodes, and MEP responses were recorded in the four extremity muscles. A decrease of more than 50% in the MEP or the SSEP amplitudes compared with baseline was used as a warning criterion. RESULTS: In the TLE surgery group without MEP monitoring, postoperative permanent motor deficits newly developed in 7 of 613 patients. In contrast, no permanent motor deficit occurred in 279 patients who received transcranial MEP and SSEP monitoring. Ten patients who exhibited decreases of more than 50% in the MEP amplitude recovered completely, although two cases showed transient motor deficits that recovered within 3 months postoperatively. CONCLUSIONS: Intraoperative transcranial MEP monitoring during TLE surgery allowed the prompt detection and appropriate correction of injuries to the motor nervous system or ischemic stroke. Intraoperative transcranial MEP monitoring is a reliable modality for minimizing motor deficits in TLE surgery.
Electrodes ; Epilepsy, Temporal Lobe ; Evoked Potentials, Somatosensory ; Extremities ; Humans ; Intraoperative Neurophysiological Monitoring ; Monitoring, Intraoperative ; Muscles ; Nervous System ; Stroke ; Temporal Lobe

Currently, anesthesiologists use clinical parameters to directly measure the depth of anesthesia (DoA). This clinical standard of monitoring is often combined with brain monitoring for better assessment of the hypnotic component of anesthesia. Brain monitoring devices provide indices allowing for an immediate assessment of the impact of anesthetics on consciousness. However, questions remain regarding the mechanisms underpinning these indices of hypnosis. By briefly describing current knowledge of the brain's electrical activity during general anesthesia, as well as the operating principles of DoA monitors, the aim of this work is to simplify our understanding of the mathematical processes that allow for translation of complex patterns of brain electrical activity into dimensionless indices. This is a challenging task because mathematical concepts appear remote from clinical practice. Moreover, most DoA algorithms are proprietary algorithms and the difficulty of exploring the inner workings of mathematical models represents an obstacle to accurate simplification. The limitations of current DoA monitors - and the possibility for improvement - as well as perspectives on brain monitoring derived from recent research on corticocortical connectivity and communication are also discussed.
Anesthesia* ; Anesthesia, General ; Anesthetics ; Brain* ; Consciousness ; Electroencephalography ; Hypnosis ; Intraoperative Awareness ; Intraoperative Neurophysiological Monitoring ; Mathematical Concepts ; Models, Theoretical

PURPOSE: The aim of this study is to analyze postoperative outcomes for carotid endarterectomy (CEA) in addition to the preoperative clinical characteristics related to selective shunting based on dual monitoring with stump pressure (SP) and electroencephalography (EEG). MATERIALS AND METHODS: We retrospectively reviewed medical records of 70 patients who underwent CEA from March 2010 to December 2017. CEA was performed under general anesthesia and selective shunting was done if the SP was lower than 35 mmHg regardless of EEG or if intraoperative EEG showed any changes different from preoperative one regardless of SP. RESULTS: There was no postoperative 30-day adjusted mortality or adverse cardiac events. Three patients (4.3%) had postoperative minor stroke finally reaching pre-operative neurologic status at the time of discharge. Twenty-six patients (37.1%) used shunting and severe contralateral internal carotid stenosis or occlusion was related to shunting (P < 0.010). There were larger number of symptomatic patients in shunt group in spite of no statistical significance (P=0.116). CONCLUSION: Perioperative stroke rate was 4.3% for CEA under general anesthesia based on dual intraoperative monitoring with SP and EEG. There was no 30-day adjusted mortality and adverse cardiac event. Severe stenosis or occlusion of contralateral internal carotid artery is related to shunting (P < 0.010).
Anesthesia, General ; Carotid Artery Diseases ; Carotid Artery, Internal ; Carotid Stenosis ; Constriction, Pathologic ; Electroencephalography ; Endarterectomy ; Endarterectomy, Carotid ; Humans ; Intraoperative Neurophysiological Monitoring ; Medical Records ; Monitoring, Intraoperative ; Mortality ; Retrospective Studies ; Stroke

OBJECTIVE: Because the anatomical structure of the brachial plexus is very complex, surgical treatment of tumors in this region is challenging. Therefore, a lot of clinical and surgical experience is required for successful treatment; however, many neurosurgeons have difficulty accumulating this experience owing to the rarity of brachial plexus tumors. The purpose of this report is to share our surgical experience with brachial plexus tumor with other neurosurgeons.METHODS: The records of 18 consecutive patients with brachial plexus tumors who underwent surgical treatment between January 2010 and December 2017 in a single institution were retrospectively reviewed. The surgical approach was determined according to the tumor location and size, and intraoperative neurophysiological monitoring (IONM) was used in most of cases to prevent iatrogenic nerve injury during surgery. In addition, to evaluate the differences in tumor characteristics according to pathologic diagnosis, the tumors were divided twice into two groups, based on two separate classifications, and statistical analysis was performed.RESULTS: The 18 brachial plexus tumors comprised 15 (83.3%) benign peripheral nerve sheath tumors including schwannoma and neurofibroma, one (5.6%) malignant peripheral nerve sheath tumor, one (5.6%) benign tumor of non-neural sheath origin (neurogenic cyst), and one (5.6%) metastatic tumor (papillary carcinoma). The authors analyzed relationship between tumor size/location and tumor characteristic parameters such as age, size, right-left, and pathology. There were no statistically significant differences except a tendency of bigger tumor size in young age.CONCLUSION: For a successful surgical outcome, an appropriate surgical approach is essential, and the appropriate surgical approach is determined by the location and size of the tumor. Furthermore, applying IONM may prevent postoperative complications and it is favorable option for brachial plexus tumors surgery.
Brachial Plexus Neuropathies ; Brachial Plexus ; Classification ; Diagnosis ; Humans ; Intraoperative Neurophysiological Monitoring ; Monitoring, Intraoperative ; Nerve Sheath Neoplasms ; Neurilemmoma ; Neurofibroma ; Neurosurgeons ; Pathology ; Peripheral Nerves ; Postoperative Complications ; Retrospective Studies

OBJECTIVE: The main aim of the present study is to examine the electrode configurations used to record the muscle motor evoked potential (mMEP) in the upper extremities during surgery with the goal of producing a high and stable mMEP signal, in particular among the abductor pollicis brevis (APB), abductor digiti minimi (ADM), and across the APB-ADM muscles, which have been widely used for the mMEP in the upper extremities. METHODS: Thirty right-handed patients were recruited in this prospective study. No patients showed any adverse events in their mMEP signals of the upper extremities during surgery. The mMEPs were recorded independently from the signals for the APB and ADM and for those across the APB-ADM. RESULTS: The mMEP amplitude from across the APB-ADM was statistically higher than those recorded from the APB and ADM muscles. Moreover, the coefficient of variation of the mMEP amplitude from across the APB-ADM was smaller than those of mMEP amplitude recorded from the APB and ADM muscles. CONCLUSION: The mMEP from across the APB-ADM muscles showed a high yield with high stability compared to those in each case from the APB and ADM muscles. The configuration across the APB-ADM muscles would be best for mMEP recordings from the upper extremities for intraoperative neurophysiological monitoring purposes.
Electrodes* ; Evoked Potentials, Motor* ; Humans ; Intraoperative Neurophysiological Monitoring* ; Muscles ; Prospective Studies ; Upper Extremity*

BACKGROUND: The differences between neuromuscular blocking (NMB) drugs on the efficacy of intraoperative motor-evoked potential (MEP) monitoring have not been established through clinical study. We compared the effects of vecuronium and cisatracurium on the efficacy of intraoperative MEP monitoring. METHODS: We enrolled 72 patients who had undergone neurosurgery with MEP monitoring. We randomly allocated the subjects into one of two groups, in whom we maintained continuous intravenous vecuronium (Group V) or cisatracurium (Group C) infusion during the surgeries; the target partial NMB for maintenance was T1/Tc 50% (T1, first twitch of TOF response; Tc, control response of T1 before NMB drug injection). We compared the means and coefficients of variation (CV, %) of all measured MEP amplitudes and the frequencies of NMB drug dose changes. RESULTS: The means and CVs of MEP amplitude and latency in all four limbs did not differ significantly between the groups, although we did change the continuous NMB drug doses in group V significantly less often than in group C. CONCLUSIONS: There were no significant differences between vecuronium and cisatracurium on the MEP variability and mean amplitudes. However, cisatracurium needed more frequent dose changes to maintain T1/Tc 50%.
Clinical Study ; Extremities ; Humans ; Intraoperative Neurophysiological Monitoring ; Neuromuscular Blockade ; Neurosurgery* ; Vecuronium Bromide*

PURPOSE: The aim of this study was to evaluate the feasibility of monitoring external branch of the superior laryngeal nerve (EBSLN) during robotic thyroid surgery. METHODS: A total of 10 patients undergoing bilateral axillo-breast approach (BABA) robotic thyroid surgery were enrolled. The nerve integrity monitor (NIM Response 2.0 System) was used for EBSLN monitoring. We performed voice assessments preoperatively and at 1 and 3 months postoperatively using Voice Handicap Index-10 (VHI-10), maximal phonation time (MPT), phonation efficient index (PEI), and laryngeal electromyography (EMG). RESULTS: A total of 19 EBSLNs were at risk and 14 EBSLNs (73.7%) were identified using neuromonitoring. VHI-10 showed a change of voice over time (0.1 vs. 3.6 vs. 1.3); however, this was not statistically significant. VHI-10 scores normalized at 3 months postoperatively compared to the preoperative scores. MPT (a) (16.0 vs. 15.6 vs. 15.4), and MPT (e) (20.1 vs. 15.4 vs. 18.5) showed no significant differences preoperatively compared to the values obtained 1 and 3 months postoperatively. There was a significant change of PEI over time (4.8 vs. 1.1 vs. 4.6) (P = 0.036); however, the values normalized at 3 months postoperatively. Laryngeal EMG results showed 4 cases (21.2%) of neuropathy of EBSLNs at 1 month postoperatively, and electrodiagnostic studies revealed nearly complete recovery of the function of EBSLNs in 4 patients at 3 months postoperatively CONCLUSION: It is suggested that neuromonitoring of EBSLNs during BABA robotic thyroid surgery is feasible and might be helpful to preserve voice quality.
Electromyography ; Humans ; Intraoperative Neurophysiological Monitoring ; Laryngeal Nerves* ; Phonation ; Prospective Studies* ; Thyroid Gland* ; Thyroidectomy ; Voice ; Voice Quality

PURPOSE: Thyroid reoperations are surgically challenging because of significant anatomical variance. Visual and functional identification of the external branch of the superior laryngeal nerve (EBSLN) were studied in 2 groups of patients who underwent primary and redo thyroid surgery. METHODS: This study was conducted on 200 patients: 100 patients with redo and 100 patients with primary thyroid surgery. In addition to visual identification, nerve branches were functionally identified by intraoperative nerve monitoring (IONM). Visual, functional, and total identification rates of the EBSLN in both primary and redo surgery were determined and compared between the 2 groups. RESULTS: We attempted to identify 138 and 170 EBSLNs at risk in redo and primary surgery, respectively. Visual identification rates were 65.3% and 30.4% (P < 0.001) in primary and redo surgery groups, respectively. In total, 164 (96.5%) and 97 EBSLNs (70.3%) were identified in primary and redo surgery, respectively (P < 0.001), including the use of IONM. In primary surgery group, 53 nonvisualized EBSLNs of 164 identified nerves (32.3%) were determined by IONM alone. In redo surgery group, 55 of 97 identified nerves (56.7%) were determined by IONM alone (P < 0.001). CONCLUSION: Both visual and total identification rates of the EBSLN are significantly decreased in reoperative thyroidectomy. IONM increases the total identification rate of the EBSLN in primary and redo thyroid surgery. Electrophysiological monitoring makes a substantial contribution to the identification of the EBSLN both in primary and especially in redo thyroid surgery.
Goiter ; Humans ; Intraoperative Neurophysiological Monitoring ; Laryngeal Nerves ; Recurrence ; Thyroid Gland ; Thyroidectomy