• Korean Journal of Clinical Laboratory Science
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• v.43 no.1
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• pp.19-25
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• 2011

The purpose of this study was to analyse brainstem auditory evoked potentials (BAEP) wave change data during microvascular decompression (MVD). The nerve function of Cranial Nerve VIII is at risk during MVD. Intraoperative monitoring of BAEP can be a useful tool to decrease the danger of hearing loss. Between January and December 2009, 242 patients had MVD for hemifacial spasm (HFS) and trigeminal neuralgia (TN). Among intraoperative BAEP changes, amplitude of V-V' was the most frequently observed during cerebellar retraction and decompression step of the MVD procedure. 138 patients (57%) had no BAEP change while 104 patients (42.98%) had BAEP change. 69 patients (28.5%) had Type A-I, 16 patients (6.6%) had Type A-II, 5 patients (2.1%) had Type B, and 13 patients (5.37%) had Type C. MVD is a surgical procedure to relieve the symptoms (e.g. pain, muscle twitching) caused by compression of a nerve by an artery or vein. During BAEP intraoperative monitoring, the surgical step is important in interpreting the changes of wave V. Several potential mechanisms of injury may affect the cochlear nerve, and complete loss of BAEP is often associated with postoperative hearing loss. Intraoperative BAEP monitoring may provide an early warning of hearing disturbance after MVD.

• Journal of Korean Neurosurgical Society
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• v.39 no.3
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• pp.183-187
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• 2006

Objective : Hemifacial spasm has characteristic and specific electrophysiological finding, lateral spread response[LSR]. We study the correlation between change of lateral spread response during microvascular decompression[MVD] and clinical outcome after MVD. Methods : Sixty two patients with hemifacial spasm who were treated with microvascular decompression from March 2000 to February 2003 were included in this study. The monitoring of intraoperative facial electromyography[EMG] and brain stem auditory evoked potential were performed. Results : In 28 [44.7%] patients, there was persistence of lateral spread response after vascular decompression in root exit zone of facial nerve. Among these 28 patients, 9 had mild hemifacial spasm at discharge. Three out of 34 patients who had intraoperative disappearance of lateral spread response after MVD had mild hemifacial spasm. But Both groups, disappearance of LSR [Group I], and persistence [Group II] had only 2 patients with mild hemifacial spasm, and 5 patients at 3 months, respectively. Conclusion : Although intraoperative EMG monitoring is very useful in assessing the efficacy of MVD, the clinical outcome of MVD in patient with hemifacial spasm does not always correlate with EMG finding. The prognostic value of intraoperative LSR monitoring in the long-term results is questionable.

• Korean Journal of Clinical Laboratory Science
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• v.46 no.1
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• pp.38-45
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• 2014

Intraoperative Neurophysiological Monitoring (INM) inspection has a very important role. While preserving the patient's neurological function be sure to safe surgery, neurological examination should thank. Cerebello pontine angle tumor surgery, especially in the nervous system is more important to the meaning of INM. In cochlear nerve, facial nerve, trigeminal nerve, which are intricate brain surgery, doctors are only human eye and brain to the brain that it is virtually impossible to distinguish the nervous system. They receives a lot of help from INM. In this paper, we examined six kinds broadly. First, the methods of spontaneous EMG and Free-running EMG, which can instantly detect a damage inflicted on a nerve during surgery. Second, methods of triggered EMG and direct nerve electrical stimulation, which directly stimulate a nerve using electricity to distinguish between nerves and brain tumors. Third, the method of knowing a more accurate neurologic status by informing neurological surgeons about Free-running EMG wave forms that are segmetalized into four. Fourth, three ways of knowing when a patient will be awaken from intraoperative anesthesia, which happens due to a weak anesthetic. Fifth, a method of understanding the structures of a brain tumor and a facial nerve as five dividend segments. Sixth, comparisons between cases normal facial nerve recovery and occurrence of a facial nerve paralysis during the postoperative course.

• Korean Journal of Clinical Laboratory Science
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• v.45 no.2
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• pp.77-85
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• 2013

Intraoperative Neurophysiological Monitoring (INM) is very useful in monitoring the motorsensory pathway and vascular circulation system during intraspinal, or intracranial neurosurgery. Brainstem Auditory Evoked Potentials (BAEPs) are for detecting the problems along the auditory pathways including, the eighth cranial nerve and brainstem. Motor Evoked Potentials (MEPs) is a useful adjunct to conventional monitoring of Somato-sensory Evoked Potentials (SEPs) during surgery. Visual Evoked Potentials (VEPs) has been regarded as having limited significance for the preservation of visual function during neurosurgical procedures. In this paper, we propose that the most appropriate averaging of the number of inspections in the inspection of each used in the operative field, is good and efficient, functionally.

• Annals of Clinical Neurophysiology
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• v.1 no.1
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• pp.70-75
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• 1999

Trancranial Doppler(TCD) monitoring is a new application of ultrasonography which allows the nonivasive detection of blood flow velocity in the horizontal (M1) segment of the middle cerebral artery (MCA) and detects microembolic phenomena in the cerebral circulation. Recent studies emphasized the potential of using this technique in vascular surgery (carotid endarterectomy, cardiopulmonary bypass), interventional and intensive care setting. Although the disparity between CBF and blood flow velocity and number of microemboli could be used to prevent cerebral ischemic and embolism based on clinical studies. A reduction of more than 60% of MCA can reflex hemodynamic ischemic state and acoustic feedback of high intensity transient signals(HITS) from the TCD monitoring unit has a direct influence on surgical technique. TCD monitoring can immediately provide information about thromboembolism and hemodynamic changes, which may be a useful tool in the study and prevention of stroke.

• International journal of advanced smart convergence
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• v.9 no.3
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• pp.71-77
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• 2020

This study was conducted in order to determine how reductions in blood pressure during surgery affect intraoperative neuromonitoring. This retrospective study considered a total of 339 patients: 194 patients with normal neuromonitoring findings (57%), 145 (42%) with abnormal neuromonitoring findings, and 34 (10%) with postoperative neurological deficits. Comparisons between the three groups revealed that overall blood pressure during surgery, postoperative blood pressure, and the difference between the maximum and minimum blood pressure could affect the intraoperative neuromonitoring findings. While we indicate that a drop in blood pressure to below 70 mmHg could affect neuromonitoring results, differences in the dosage of anesthetic agents did not significantly affect reductions in blood pressure or neuromonitoring findings. The association of monitoring with blood pressure found in this study is expected to help future examiners. However, this study did not clarify the relationship between anesthesia and blood pressure and how it could affect intraoperative neuromonitoring. Therefore, further research on this part is thought to be necessary.

• International journal of advanced smart convergence
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• v.9 no.4
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• pp.8-15
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• 2020

This study was conducted in order to determine the effect of intraoperative hemoglobin changes on intraoperative neuromonitoring (IONM). This was a retrospective study that included 339 participants who underwent cerebrovascular surgery. We compared anesthetic agents, intraoperative hemoglobin, hematocrit, blood transfusion, and blood loss. We examined motor evoked potential and sensory evoked potential to patients. There were significant differences in hemoglobin changes, bleeding levels, transfusion, anesthesia time, and postoperative mobility disorders. Moreover, compared with patients who received transfusions, those who did not receive transfusion had a lower average hemoglobin level, as well as a higher bleeding amount, and a need of higher anesthesia time and anesthetic dose. Also, we found vasospasm occurred while surgery can bring adverse results after operation. This study showed that an intraoperative decrease in hemoglobin levels affects the function of cerebral perfusion, which could result in abnormal nerve monitoring results. However, as this study could not find a relation of anesthetics to IONM, there is a need for further research regarding the association between anesthetics and hemoglobin changes and IONM.

• Annals of Clinical Neurophysiology
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• v.24 no.1
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• pp.21-25
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• 2022

The newly identified frontal aslant tract (FAT) that connects the posterior Broca's area to the supplementary motor area is known to be involved in speech and language functions. We successfully intraoperatively monitored FAT using cortico-cortical evoked potentials generated by single-pulse electrical cortical stimulation in a patient with oligodendroglioma.

• Journal of Chest Surgery
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• v.56 no.5
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• pp.336-345
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• 2023

Background: The objective of this study was to demonstrate the safety, efficacy, and feasibility of intraoperative monitoring of the recurrent laryngeal nerves during thoracoscopic and robotic 3-field esophagectomy. Methods: This retrospective analysis details our initial experience using intraoperative nerve monitoring (IONM) during minimally invasive 3-field esophagectomy. Data were obtained from a prospectively maintained database and electronic medical records. The study included all patients who underwent minimally invasive (video-assisted thoracic surgery/robotic) transthoracic esophagectomy with neck anastomosis. The patients were divided into those who underwent IONM during the study period and a historical cohort who underwent 3-field esophagectomy without IONM at the same institution. Appropriate statistical tests were used to compare the 2 groups. Results: Twenty-four patients underwent nerve monitoring during minimally invasive 3-field esophagectomy. Of these, 15 patients underwent thoraco-laparoscopic operation, while 9 received a robot-assisted procedure. In the immediate postoperative period, 8 of 24 patients (33.3%) experienced vocal cord paralysis. Relative to a historical cohort from the same institution, who were treated with surgery without nerve monitoring in the preceding 5 years, a 26% reduction was observed in the nerve paralysis rate (p=0.08). On follow-up, 6 of the 8 patients with vocal cord paralysis reported a return to normal vocal function. Additionally, patients who underwent IONM exhibited a higher nodal yield and a decreased frequency of tracheostomy and bronchoscopy. Conclusion: The use of IONM during minimally invasive 3-field esophagectomy is safe and feasible. This technique has the potential to decrease the incidence of recurrent nerve palsy and increase nodal yield.

• Annals of Clinical Neurophysiology
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• v.1 no.1
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• pp.19-25
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• 1999

Background & Objectives : In cerebral palsy, spastic paraplegia is one of the most crippling motor manifestations. Reducing the spasticity may improve gait and decrease the incidence of lower-extremity deformities. The spasticity may result from abnormally increased afferent signals via dorsal roots onto interneurons and anterior horn and spreading of reflex activation to other muscle groups. To assess the influence of dorsal rhizotomy to spasticity, the authors analyzed five cerebral palsy patients with spastic paraplegia. Methods : The operation entailed and L1-2 laminectomy, ultrasonographic localization of conus medullaris and identification of lumbosacral dorsal roots. The innervation patterns of each dorsal root were examined by electromyography (EMG) responses to electrical stimulation. Tetanic stimulation was applied to individual rootlets of each root after reflex threshold was determined. the reflex responses were graded and rootlets producing high grade response were selected and cut. Short-term postoperative evaluations were performed. Results : Intraoperative EMG monitoring was satisfactorily performed in all five cases. One month after the operations, all patients showed greatly reduced spasticity which was measured by the instrumental gait analysis. Bilateral knee and ankle jerks were normalized and tip-toe gait with scissoring disappeared in all patients. Conclusion : Intraoperative EMG monitoring seems useful for the selective dorsal rhizotomy to reduce spasticity.