• International journal of thyroidology
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• v.11 no.2
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• pp.130-136
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• 2018

Background and Objectives: Intraoperative neural monitoring (IONM) of recurrent laryngeal nerve (RLN) in thyroid surgery has been employed worldwide to identify and preserve the nerve as an adjunct to visual identification. The aims of this study was to evaluate the efficacy of IONM and difficulties in the learning curve. Materials and Methods: We studied 63 patients who underwent thyroidectomy with IONM during last 2 years. The standard IONM procedure was performed using NIM 3.0 or C2 Nerve Monitoring System. Patients were divided into two chronological groups based on the success rate of IONM (33 cases in the early period and 30 cases in the late period), and the outcomes were compared between the two groups. Results: Of 63 patients, 32 underwent total thyroidectomy and 31 thyroid lobectomy. Failure of IONM occurred in 9 cases: 8 cases in the early period and 1 case in the late period. Loss of signal occurred in 8 nerves of 82 nerves at risk. The positive predictive value increased from 16.7% in the early period to 50% in the late period. The mean amplitude of the late period was higher than that of the early period (p<0.001). Conclusion: IONM in thyroid surgery is effective to preserve the RLN and to predict postoperative nerve function. However, failure of IONM and high false positive rate can occur in the learning curve, and the learning curve was about 30 cases based on the results of this study.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.1
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• pp.61-67
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• 2022

Intraoperative neurophysiological monitoring (INM) ensures the stability and safety of specific surgeries in high-risk groups. As part of INM, intensive tests are conducted during the surgical process. When INM tests are applied during surgery, a delay in notifying the operating surgeon in cases of neurological defects can cause serious irreversible sequelae to the patient. Aortic replacement, which is necessitated due to aortic aneurysms and aortic dissection, is a complicated procedure that blocks the blood flow to the heart. When arteries that branch out from the aorta and supply blood to the spinal cord are replaced, blood flow to the spinal cord decreases, resulting in spinal ischemia. In aortic surgery, INM plays an important role in preventing spinal ischemia and serious complications by quickly detecting the early signs of spinal ischemia during cross-clamping and reporting it to the surgeon. Therefore, this paper was prepared to help examiners who conduct INM by detailing the process, method, time, and warning criteria for INM. This paper identifies the need for INM in aortic surgery and the process flow for a smooth test, accurate and rapid examination, and subsequent reporting.

• 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.

• Annals of Clinical Neurophysiology
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• v.10 no.1
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• pp.1-12
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• 2008

Intraoperative neuromonitoring (INM) is well known to be useful method to reduce intraoperative complications during the surgery of nervous system lesions. Evoked potentials are most commonly used among the electrophysiological tests. Brainstem auditory evoked potentials are for detecting the problems along the auditory pathways including the eighth cranial nerve and brainstem. Somatosensory evoked potentials are applied for preventing the spinal cord lesions. The INM is affected by many factors. In order to perform an optimal INM, the confounding factors including technical, anesthetical, and individual factors should be kept well under control. INM has frequent electrophysiologic changes during the surgery and it might be helpful to keep one's eyes on which monitoring modalities are reluctant to change during each operation. The skillful monitoring and timely interpretation of electrophysiologic changes can drive the patient to be undergone surgery, even in high surgical risk group.

• Korean Journal of Head & Neck Oncology
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• v.36 no.1
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• pp.9-14
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• 2020

Visual identification of recurrent laryngeal nerve (RLN) is considered as a gold standard of RLN preservation during thyroid surgery. Intraoperative neuromonitoring (IONM) is classified into the intermittent type and continuous type and helps surgeons identify the functional integrity of RLN and predict the postoperative vocal cord function. RLN injury during thyroid surgery is associated with tumor factors and surgeon factors. Tumor factors mean such as direct tumor invasion, adhesion of RLN to the tumor, and compression by a large thyroid tumor. Surgeon factors include nerve transection, stretching, thermal injury, and ligation injury. A recent meta-analysis reported that the IONM could reduce the RLN injury. Considering various nerve injury mechanism, we suggest that using both I-ONM and C-IONM together is more effective method in preventing nerve damage than using I-IONM alone.

• Journal of Korean Neurosurgical Society
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• v.29 no.6
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• pp.778-785
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• 2000

Objectives : Intraoperative neurophysiologic monitoring(INM) is a well known useful method to reduce intraoperative neurological complications during neurosurgical procedures. Furthermore, INM is required in most cerebellopontine angle(CPA) surgery because cranial nerves or brain stem injuries can result in serious complications. Object of this study is to the correlation between the changes of intraoperative monitoring modalities during cerebellopontine angle tumor surgery and post-operative functional outcomes in auditory and facial functions. Material and Methods : Fifty-seven patients who underwent intraoperative neurophysiologic monitoring during CPA tumor surgery were retrospectively reviewed. Their lesions were as follows ; vestibular schwannomas in 42, other cranial nerve schwannomas in seven, meningiomas in five and cysts in three cases. Pre- and postoperative audiologic examinations and facial nerve function tests were performed in all patients. Intraoperative neurophysiologic monitoring modalities includes brainstem auditory evoked potentials(BAEP) and facial electromyographies(EMG). We compared the events of INM during CPA tumor surgeries with the outcomes of auditory and facial nerve functions. Results : The subjects who had abnormal changes during CPA tumor surgery were twenty cases with BAEP changes and facial EMG changes in twenty one cases. The changes of intraoperative neurophysiologic monitoring did not always result in poor functional outcomes. However, most predictable intraoperative monitoring changes were wave III-V complex losses in BAEP and continuous neurotonic activities in facial EMG. Conclusion : These results indicate that intraoperative neurophysiologic monitoring in CPA tumor surgery usually provide predictive value for postoperative functional outcomes.

• Journal of Chest Surgery
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• v.38 no.2 s.247
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• pp.152-156
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• 2005

Background: Occlusive complications after arterial revascularization are difficult to treat and have high recurrence rate. This study was performed to establish an effective treatment modality and to evaluate the factors affecting the occlusive complications by analysis of clinical data. Material and Method: During the period of 5 years. 33 patients (55 reoperations) were studied at the Department of Thoracic and Cardiovascular Surgery, Pusan National University Hospital following 173 arterial revascularization surgeries. The clinical characteristics, operating methods, the time intervals of reoperation, used graft, and the results of treatment were evaluated retrospectively. Result: All the patients were men except one and the mean age was 63.5 years old. The mean time internal from first operation to reoperation was 11.9 months. The cause of arterial occlusive diseases were 28 atherosclerosis and 5 Burger's diseases, Associated diseases were Hypertension $(57.6\%)$, Diabetes mellitus $(33.3\%)$, heart failure $(18.2\%)$, and so on. The mean rate of reoperation was 1.67 times and the most common type of first operation was femoro-popliteal bypass grafting $(57.6\%)$. The graft that used revascularization surgery were 25 cases of PTFE and 6 case were Dacron. There was no statistical difference between two groups. The kinds of reoperations were thrombectomy in 20 cases, angioplasty 18 cases, re-bypass surgery in 13 cases, and lumbar sympathectomy in 4 cases. The results of reoperation were 15 cases of functional recovery, 7 cases of limb salvage, 5 cases of above-knee amputation. 3 cases of below-knee amputation and 3 deaths. Conclusion: The main cause of occlusive complications are occlusion of inflow or outflow artery. Treatments were different according to the first operation methods and graft used. The most frequent time of reoperation was within one year after the first operation. We believe that graft surveillance especially during the first year is very important factor in observing the patient. We can look forward to improving limb salvage rate to perform additional treatment such as radiological interventions and lumbar sympathectomy.

• Journal of Yeungnam Medical Science
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• v.24 no.2
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• pp.206-215
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• 2007

Background : The prone position is often used for operations involving the spine and provides excellent surgical access. The complications associated with the prone position include ocular and auricular injuries, and musculoskeletal injuries. In particular, the prone position during general anesthesia causes hemodynamic changes. To evaluate the cardiovascular effects of the prone position in surgical patients during general anesthesia, we investigated the effects on hemodynamic change of the prone position with the Jackson spinal surgery table. Materials and Methods : Thirty patients undergoing spine surgery in the prone position were randomly selected. After induction of general anesthesia, intra-arterial and central venous pressures (CVP) were monitored and cardiac output was measured by $NICO^{(R)}$. We measured stroke volume, cardiac index, cardiac output, mean arterial pressure, heart rate, CVP and systemic vascular resistance (SVR) before changing the position. The same measurements were performed after changing to the prone position with the patient on the Jackson spinal surgery table. Results : In the prone position, there was a significant reduction in stroke volume, cardiac index and cardiac output. The heart rate, mean arterial pressure and CVP were also decreased in the prone position but not significantly. However, the SVR was increased significantly. Conclusion : The degree of a reduced cardiac index was less on the Jackson spinal surgery table than other conditions of the prone position. The reduced epidural pressure caused by free abdominal movement may decrease intraoperative blood loss. Therefore, the Jackson spinal surgery table provides a convenient and stable method for maintaining patients in the prone position during spinal surgery.

• 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.