General anesthesia, pivotal for surgical procedures, requires precise depth monitoring to mitigate risks ranging from intraoperative awareness to postoperative cognitive impairments. Traditional assessment methods, relying on physiological indicators or behavioral responses, fall short of accurately capturing the nuanced states of unconsciousness. This study introduces a machine learning-based approach to decode anesthesia depth, leveraging EEG data across different anesthesia states induced by propofol and esketamine in rats. Our findings demonstrate the model's robust predictive accuracy, underscored by a novel intra-subject dataset partitioning and a 5-fold cross-validation method. The research diverges from conventional monitoring by utilizing anesthetic infusion rates as objective indicators of anesthesia states, highlighting distinct EEG patterns and enhancing prediction accuracy. Moreover, the model's ability to generalize across individuals suggests its potential for broad clinical application, distinguishing between anesthetic agents and their depths. Despite relying on rat EEG data, which poses questions about real-world applicability, our approach marks a significant advance in anesthesia monitoring.
Animals ; Machine Learning ; Electroencephalography/methods* ; Ketamine/administration & dosage* ; Rats ; Male ; Propofol/administration & dosage* ; Rats, Sprague-Dawley ; Anesthesia, General/methods* ; Brain/physiology* ; Intraoperative Neurophysiological Monitoring/methods*

Selective dorsal neurotomy (SDN) is a surgical treatment for primary premature ejaculation (PE), but there is still no standard surgical procedure for selecting the branches of the dorsal penile nerves to be removed. We performed this study to explore the value of intraoperative neurophysiological monitoring (IONM) of the penile sensory-evoked potential (PSEP) for standard surgical procedures in SDN. One hundred and twenty primary PE patients undergoing SDN were selected as the PE group and 120 non-PE patients were selected as the normal group. The PSEP was monitored and compared between the two groups under both natural and general anesthesia (GA) states. In addition, patients in the PE group were randomly divided into the IONM group and the non-IONM group. During SDN surgery, PSEP parameters of the IONM group were recorded and analyzed. The differences in PE-related outcome measurements between the perioperative period and 3 months' postoperation were compared for the PE patients, and the differences in effectiveness and complications between the IONM group and the non-IONM group were compared. The results showed that the average latency of the PSEP in the PE group was shorter than that in the normal group under both natural and GA states (P < 0.001). Three months after surgery, the significant effective rates in the IONM and non-IONM groups were 63.6% and 34.0%, respectively (P < 0.01), and the difference in complications between the two groups was significant (P < 0.05). IONM might be useful in improving the short-term therapeutic effectiveness and reducing the complications of SDN.
Male ; Humans ; Premature Ejaculation/surgery* ; Intraoperative Neurophysiological Monitoring/methods* ; Prospective Studies ; Neurosurgical Procedures/methods* ; Penis/surgery* ; Retrospective Studies

Hemifacial spasm (HFS) is due to the vascular compression of the facial nerve at its root exit zone (REZ). Microvascular decompression (MVD) of the facial nerve near the REZ is an effective treatment for HFS. In MVD for HFS, intraoperative neurophysiological monitoring (INM) has two purposes. The first purpose is to prevent injury to neural structures such as the vestibulocochlear nerve and facial nerve during MVD surgery, which is possible through INM of brainstem auditory evoked potential and facial nerve electromyography (EMG). The second purpose is the unique feature of MVD for HFS, which is to assess and optimize the effectiveness of the vascular decompression. The purpose is achieved mainly through monitoring of abnormal facial nerve EMG that is called as lateral spread response (LSR) and is also partially possible through Z-L response, facial F-wave, and facial motor evoked potentials. Based on the information regarding INM mentioned above, MVD for HFS can be considered as a more safe and effective treatment.
Decompression ; Electromyography ; Evoked Potentials, Auditory, Brain Stem ; Evoked Potentials, Motor ; Facial Nerve ; Hemifacial Spasm ; Intraoperative Neurophysiological Monitoring ; Microvascular Decompression Surgery ; Vestibulocochlear Nerve

PURPOSE: The perigastric vagus nerve may play an important role in preserving function after gastrectomy, and intraoperative neurophysiologic tests might represent a feasible method of evaluating the vagus nerve. The purpose of this study is to assess the feasibility of neurophysiologic evaluations of the function and viability of perigastric vagus nerve branches during gastrectomy. MATERIALS AND METHODS: Thirteen patients (1 open total gastrectomy, 1 laparoscopic total gastrectomy, and 11 laparoscopic distal gastrectomy) were prospectively enrolled. The hepatic and celiac branches of the vagus nerve were exposed, and grabbing type stimulation electrodes were applied as follows: 10–30 mA intensity, 4 trains, 1,000 µs/train, and 5× frequency. Visible myocontractile movement and electrical signals were monitored via needle probes before and after gastrectomy. Gastrointestinal symptoms were evaluated preoperatively and postoperatively at 3 weeks and 3 months, respectively. RESULTS: Responses were observed after stimulating the celiac branch in 10, 9, 10, and 6 patients in the antrum, pylorus, duodenum, and proximal jejunum, respectively. Ten patients responded to hepatic branch stimulation at the duodenum. After vagus-preserving distal gastrectomy, 2 patients lost responses to the celiac branch at the duodenum and jejunum (1 each), and 1 patient lost response to the hepatic branch at the duodenum. Significant procedure-related complications and meaningful postoperative diarrhea were not observed. CONCLUSIONS: Intraoperative neurophysiologic testing seems to be a feasible methodology for monitoring the perigastric vagus nerves. Innervation of the duodenum via the celiac branch and postoperative preservation of the function of the vagus nerves were confirmed in most patients. TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0000823
Diarrhea ; Duodenum ; Electrodes ; Gastrectomy ; Humans ; Information Services ; Intraoperative Neurophysiological Monitoring ; Jejunum ; Methods ; Needles ; Prospective Studies ; Pylorus ; Vagus Nerve

OBJECTIVE: To compare the application of multi-mode and single-mode intraoperative neurophysiological monitoring in the treatment of severe ossification of posterior longitudinal ligament of cervical spine with anterior cervical corpectomy with fusion. METHODS: From April 2015 to June 2018, 32 patients with severe ossification of the posterior longitudinal ligament were treated in the Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine. There were 21 males and 11 females, aged 45 to 73 years old, with a mean age of 59 years old. The duration of the disease ranged from 6 to 72 months, with a mean of 39 months. The main manifestations were numbness, numbness and weakness of limbs, cotton feeling of foot stepping on lower limbs, instability of standing and walking. With the gradual aggravation of symptoms, quadriplegia, dysfunction of urine and defecation may occur. Patients with ossification of posterior longitudinal ligament of cervical spine were monitored by somatosensory evoked potentials, motor evoked potentials and electromyogram patterns. RESULTS: During the operation, 8 patients had abnormal amplitude of somatosensory evoked potential(SEP); 5 of them had bleeding during anterior cervical decompression procedure and were placed with too much hemostatic cotton, which caused compression of spinal cord and resulted in abnormal SEP waveform. After removal of the hemostatic cotton, SEP waveform returned ot normal; 3 patients had abnormal SEP waveform due to decreased systolic pressure, which was corrected by increased systolic pressure. Twelve patients had abnormal amplitude of motor evoked potential during monitoring, 9 of which were caused by intraoperative mis-contact with nerve root, and turned to normal after timely adjustment of position, 3 of which were caused by intraoperative inhalation of muscle relaxant during surgery. Among 11 patients with abnormal EMG waveform, 9 patients recovered to normal waveform after adjusting operation, 2 patients recovered to normal waveform after short observation, and all patients recovered to normal waveform of motor evoked potential after operation(<0.05). There were 2 cases of cerebrospinal fluid leakage after operation, which healed spontaneously 7 days after operation, and no complications of spinal cord and nerve occurred in all patients after operation. CONCLUSIONS In anterior cervical corpectomy with fusion operation for the treatment of severe cervical ossification of posterior longitudinal ligament, various modes of intraoperative neurophysiological monitoring can real-time understand spinal cord and nerve function status, significantly reduce the incidence of spinal cord and nerve injury during operation, and effectively improve the safety of operation.
Aged ; Cervical Vertebrae ; China ; Decompression, Surgical ; Female ; Humans ; Intraoperative Neurophysiological Monitoring ; Longitudinal Ligaments ; Male ; Middle Aged ; Ossification of Posterior Longitudinal Ligament ; Osteogenesis ; Retrospective Studies ; Spinal Fusion ; Treatment Outcome

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

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

OBJECTIVES: False-negative or false-positive responses in intraoperative neuromonitoring (IONM) using electromyography (EMG) in thyroid surgery pose a challenge. Therefore, we developed a novel IONM system that uses a surface pressure sensor instead of EMG to detect muscle twitching. This study aimed to investigate the feasibility and safety of a new IONM system using a piezo-electric surface pressure sensor in an experimental animal model. METHODS: We developed the surface pressure sensor by modifying a commercial piezo-electric sensor. We evaluated the stimulus thresholds to detect muscle movement, as well as the amplitude and latency of the EMG and surface pressure sensor in six sciatic nerves of three rabbits, according to the stimulus intensity. RESULTS: The surface pressure sensor detected the muscle movements in response to a 0.1 mA stimulation of all six sciatic nerves. There were no differences in the thresholds of stimulus intensity between the surface pressure sensor and EMG recordings to detect muscle movements. CONCLUSION: It is possible to measure the change in surface pressure by using a piezo-electric surface pressure sensor instead of EMG to detect muscle movement induced by nerve stimulation. The application of IONM using a piezo-electric surface pressure sensor during surgery is noninvasive, safe, and feasible. Measuring muscle twitching to identify the state of the nerves using the novel IONM system can be an alternative to recording of EMG responses.
Electromyography ; Intraoperative Neurophysiological Monitoring ; Models, Animal ; Rabbits ; Recurrent Laryngeal Nerve ; Sciatic Nerve ; Thyroid Gland ; Thyroidectomy

OBJECTIVE: The aim of this study was to investigate clinical and radiological outcomes of patients who underwent posterior vertebral column resection (PVCR) by a single neurosurgeon in a single institution.METHODS: Thirty-four consecutive patients with severe spinal deformities who underwent PVCR between 2010 and 2016 were enrolled. The radiographic measurements included a kyphotic angle of PVCR levels (VCR angle), sagittal vertical axis (SVA), thoracic kyphosis, lumbar lordosis (LL), and spinopelvic parameters. The data of surgical time, estimated blood loss, duration of hospital stay, complications, intraoperative neurophysiologic monitoring, and the Scoliosis Research Society (SRS)-22 questionnaire were collected using a retrospective review of medical records.RESULTS: The VCR angle, LL, and SVA values were significantly corrected after surgery. The VCR and LL angle were changed from the average of 38.4±32.1° and −22.1±39.1° to −1.7±29.4° (p < 0.001) and −46.3±23.8° (p=0.001), respectively. The SVA was significantly reduced from 103.6±88.5 mm to 22.0±46.3 mm (p=0.001). The clinical results using SRS-22 survey improved from 2.6±0.9 to 3.4±0.8 (p=0.033). There were no death and permanent neurological deficits after PVCR. However, complications occurred in 19 (55.9%) patients. Those patients experienced a total of 31 complications during- and after surgery. Sixteen reoperations were performed in twelve (35.3%) patients. The incidence of transient neurological deterioration was 5.9% (two out of 34 patients).CONCLUSION: Severe spinal deformities can be effectively corrected by PVCR. However, the PVCR technique should be utilized limitedly because surgery-related serious complications are relatively common.
Animals ; Congenital Abnormalities ; Humans ; Incidence ; Intraoperative Complications ; Kyphosis ; Length of Stay ; Lordosis ; Medical Records ; Neurophysiological Monitoring ; Neurosurgeons ; Operative Time ; Retrospective Studies ; Scoliosis ; Spine

Intraoperative monitoring (IOM) utilizes electrophysiological techniques as a surrogate test and evaluation of nervous function while a patient is under general anesthesia. They are increasingly used for procedures, both surgical and endovascular, to avoid injury during an operation, examine neurological tissue to guide the surgery, or to test electrophysiological function to allow for more complete resection or corrections. The application of IOM during pediatric brain tumor resections encompasses a unique set of technical issues. First, obtaining stable and reliable responses in children of different ages requires detailed understanding of normal ageadjusted brain-spine development. Neurophysiology, anatomy, and anthropometry of children are different from those of adults. Second, monitoring of the brain may include risk to eloquent functions and cranial nerve functions that are difficult with the usual neurophysiological techniques. Third, interpretation of signal change requires unique sets of normative values specific for children of that age. Fourth, tumor resection involves multiple considerations including defining tumor type, size, location, pathophysiology that might require maximal removal of lesion or minimal intervention. IOM techniques can be divided into monitoring and mapping. Mapping involves identification of specific neural structures to avoid or minimize injury. Monitoring is continuous acquisition of neural signals to determine the integrity of the full longitudinal path of the neural system of interest. Motor evoked potentials and somatosensory evoked potentials are representative methodologies for monitoring. Free-running electromyography is also used to monitor irritation or damage to the motor nerves in the lower motor neuron level : cranial nerves, roots, and peripheral nerves. For the surgery of infratentorial tumors, in addition to free-running electromyography of the bulbar muscles, brainstem auditory evoked potentials or corticobulbar motor evoked potentials could be combined to prevent injury of the cranial nerves or nucleus. IOM for cerebral tumors can adopt direct cortical stimulation or direct subcortical stimulation to map the corticospinal pathways in the vicinity of lesion. IOM is a diagnostic as well as interventional tool for neurosurgery. To prove clinical evidence of it is not simple. Randomized controlled prospective studies may not be possible due to ethical reasons. However, prospective longitudinal studies confirming prognostic value of IOM are available. Furthermore, oncological outcome has also been shown to be superior in some brain tumors, with IOM. New methodologies of IOM are being developed and clinically applied. This review establishes a composite view of techniques used today, noting differences between adult and pediatric monitoring.
Adult ; Anesthesia, General ; Anthropometry ; Brain Neoplasms ; Brain ; Child ; Cranial Nerves ; Electromyography ; Evoked Potentials, Auditory, Brain Stem ; Evoked Potentials, Motor ; Evoked Potentials, Somatosensory ; Humans ; Infratentorial Neoplasms ; Intraoperative Neurophysiological Monitoring ; Longitudinal Studies ; Monitoring, Intraoperative ; Motor Neurons ; Muscles ; Neurophysiology ; Neurosurgery ; Peripheral Nerves ; Prospective Studies