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Background: Reliable devices that quantitatively monitor the level of neuromuscular blockade after neuromuscular blocking agents’ administration are crucial. Electromyography and acceleromyography are two monitoring modalities commonly used in clinical practice. The primary outcome of this study is to compare the onset of neuromuscular blockade, defined as a Train-Of-Four Count (TOFC) equal to 0, as measured by an electromyography-based device (TetraGraph) and an acceleromyography-based device (TOFscan). The secondary outcome was to compare intubating conditions when one of these two devices reached a TOFC equal to 0. Methods: One hundred adult patients scheduled for elective surgery requiring neuromuscular blockade were enrolled. Prior to induction of anesthesia, TetraGraph electrodes were placed over the forearm of patients’ dominant/non-dominant hand based on randomization and TOFscan electrodes placed on the contralateral forearm. Intraoperative neuromuscular blocking agent dose was standardized to 0.5 mg.kg−1 of rocuronium. After baseline values were obtained, objective measurements were recorded every 20 seconds and intubation was performed using video laryngoscopy once either device displayed a TOFC = 0. The anesthesia provider was then surveyed about intubating conditions. Results: Baseline TetraGraph train-of-four ratios were higher than those obtained with TOFscan (Median: 1.02 [0.88, 1.20] vs. 1.00 [0.64, 1.01], respectively, p < 0.001). The time to reach a TOFC = 0 was significantly longer when measured with TetraGraph compared to TOFscan (Median: 160 [40, 900] vs. 120 [60, 300] seconds, respectively, p < 0.001). There was no significant difference in intubating conditions when either device was used to determine the timing of endotracheal intubation. Conclusions: The onset of neuromuscular blockade was longer when measured with TetraGraph than TOFscan, and a train-of-four count of zero in either device was a useful indicator for adequate intubating conditions. Clinical trial number and registry: URL NCT05120999, https://clinicaltrials.gov/ct2/show/NCT05120999.

Objective: Intraoperative neurophysiological monitoring in intramedullary spinal cord tumor removal surgery helps surgeons detect early warning signs of postoperative nerve damage, in order to reduce or prevent permanent neuron injury. We performed a study to evaluate the value of intraoperative neurophysiological monitoring techniques in intramedullary spinal cord tumor resection surgery. Methods: We performed a retrospective study of 29 patients undergoing surgery for intramedullary spinal cord tumors and intraoperative neurophysiological monitoring from 2017 to 2021 at the University Medical Center, Ho Chi Minh City. Clinical assessment before and after surgery, intraoperative neurophysiological monitoring to find out the sensitivity, specificity, positive predictive value, and negative predictive value of intraoperative neurophysiological monitoring techniques were performed. Results: Of the 29 patients, 4 patients had worse postoperative neurological symptoms (13.8%) at 1 day after surgery. The rate of postoperative worsening neurological symptoms decreased to 10.3% at the 1-month follow-up. SSEP (somatosensory evoked potential) had 75% sensitivity and 72% specificity in detecting postoperative nerve damage, while the sensitivity and specificity of MEP (motor evoked potential) were 100% and 80%, respectively. Conclusion: Both SSEP and MEP have a high sensitivity in detecting postoperative nerve damage, meanwhile, MEP is more sensitive than SSEP. These techniques help predict and possibly prevent timely neurological damage during intramedullary spinal cord resection surgery.

We aim to report our study about using multimodality intraoperative neurophysiological monitoring (IONM) in intradural spinal tumor surgery. This cohort present a retrospective review of the patient who underwent intraspinal tumors surgery at Vajira Center of Excellence in Neurosurgery; between 2005 and 2020. Transcranial motor evoked potentials, somatosensory evoked potentials, and free run electromyography were used for IONM with alarm criteria. Patient record were reviews with preoperative and postoperative neurological outcome measurements; Frankel Grading, McCormick Score, American Spinal Injury Association (ASIA) Grading, Karnofsky Performance Status (KPS) Scale and The Japanese Orthopedic Association (JOA) Score at 1, 6, 12, 24 months after operation. Overall, 104 patients were operated. 77.4 % operations were used IONM. 70.2 % of tumor located at intradural extramedullary (IDEM) space and 16.7 % located at intramedullary space. There were demonstrating statistically significant (p-value

Introduction: Prone position during posterior spine surgery can represent a potentially risky procedure for the nervous system. Infrequent injuries due to prone positioning consist of subtle spinal cord infarction or myelopathy that can be promptly detected by intraoperative neurophysiological monitoring (IONM), if applied in this phase of surgery. Here, we report a case that stresses the value of IONM even in detecting spinal positioning-related neurological complications during kyphoscoliosis correction. Case presentation: A 3-year-old child with a severe thoracic kyphoscoliosis with the angle in the tract T5-T6 underwent an early treatment of scoliosis with growing rods. Before instrumentation or the reduction maneuver, lower limb somatosensory and motor responses disappeared. The patient was repositioned with neck and chest in a more protective position and neuromonitoring signals returned to baseline. The surgery could be completed and the patient had no postoperative neurologic or vascular deficits. Conclusion: Our findings suggest the importance of extending neuromonitoring in the early phases of anesthesia induction and patient positioning during corrective spinal deformity surgery.

Objective: To investigate the optimal combination of somatosensory- and transcranial motor-evoked potential (SSEP/tcMEP) modalities and monitored extremities during clip reconstruction of aneurysms of the anterior cerebral artery (ACA) and its branches. Methods: A retrospective review of 104 cases of surgical clipping of ruptured and unruptured aneurysms was performed. SSEP/tcMEP changes and postoperative motor deficits (PMDs) were assessed from upper and lower extremities (UE/LE) to determine the diagnostic accuracy of each modality separately and in combination. Results: PMDs were reported in 9 of 104 patients; 7 LE and 8 UE (3.6% of 415 extremities). Evoked potential (EP) monitoring failed to predict a PMD in 8 extremities (1.9%). Seven of 8 false negatives had subarachnoid hemorrhage. Sensitivity and specificity in LE were 50% and 97% for tcMEP, 71% and 98% for SSEP, and 83% and 98% for dual-monitoring of both tcMEP/SSEP. Sensitivity and specificity in UE were 38% and 99% for tcMEP, and 50% and 97% for tcMEP/SSEP, respectively. Conclusions: Combined tcMEP/SSEP is more accurate than single-modality monitoring for LE but is relatively insensitive for UE PMDs. Significance: During ACA aneurysm clipping, multiple factors may confound the ability of EP monitoring to predict PMDs, especially brachiofacial hemiparesis caused by perforator insufficiency.

Objective: This study sought to investigate the utility of intraoperative neurophysiological monitoring (IONM) in the surgical treatment for spinal arteriovenous malformations (SAVMs). Methods: We retrospectively reviewed the data of 39 patients who underwent surgical treatment for SAVMs. Twenty-eight patients who received multimodal IONM (transcranial electrical motor-evoked potentials [MEPs], somatosensory-evoked potentials, continuous electromyography, and bulbocavernosus reflex [BCR]) between 2011 and 2020 were compared to 11 historical controls between 2003 and 2011. The rates of postoperative neurological deficits (PNDs), neurophysiological warnings, and their characteristics were analyzed. Results: PNDs were developed in 10.7% and 54.5% of patients in the IONM and historical control (non-IONM) groups, respectively (p = 0.008). Moreover, not applying IONM was the only significant risk factor for the development of PNDs in the logistic regression analysis (odds ratio 10.0, p = 0.007). In the IONM group, a total of three electrophysiological warnings were observed, and two of these were true positives; one patient complained of leg motor weakness after surgery with loss of the abductor halluces MEPs. The other patient experienced disappearance of the BCR during surgery and newly developed urinary retention. Overall, the sensitivity, specificity, positive predictive value, and negative predictive value of IONM warnings for detecting PNDs were 66.7%, 96.0%, 66.7%, and 96.0%, respectively. Conclusions: The neurological outcome of the IONM group was significantly better than that of the historical control group in the surgical treatments for SAVMs. Significance: Multimodal IONM could be a useful tool to detect neurological damage with relatively high accuracy in this type of surgery.

Introduction: Intramedullary hematoma is an uncommon, serious neurological disease, representing a diagnostic challenge. The preferred treatment is surgical. In most of the cases the lesion can be identified macroscopically. Otherwise, finding the optimal place to perform myelotomy is demanding. Intraoperative neurophysiological monitoring plays an important role in preventing surgical complications, but its versatility for localization has not been studied so far. Case report: The present case report describes a 17-year-old patient with flaccid right inferior monoparesis (later paraparesis), ipsilateral loss of proprioception and vibration sense, contralateral analgesia below the T10 dermatome level and urinary retention (Brown-Séquard syndrome). The MRI revealed an intramedullary hematoma at the level of T8-T9 vertebral bodies. Digital subtraction angiography did not identify any vascular malformation. Urgent surgical intervention was performed. In order to prevent any complication somatosensory-evoked potential (SSEP), transcranial and epidural motor-evoked potential (tcMEP, eMEP) recordings were planned. SSEP in response to right tibial nerve stimulation and tcMEP were absent bilaterally. From electrophysiological point of view, the eMEP revealed a total conduction block of the corticospinal tract. In the absence of typical macroscopic signs (discoloration, swelling, abnormal vascularization etc.), the small intramedullary hematoma could not be identified. Therefore, it was decided to adopt eMEP technique for mapping and localizing the conduction block intraoperatively by changing the distance between the two electrodes used for recording. The hematoma was precisely localized and successfully evacuated. Postoperatively, a slow but continuous improvement was noted. Conclusion: Intraoperative neurophysiological monitoring has been suggested to play crucial role in spinal cord surgery. To our knowledge, this is the first case report using eMEP recording for guiding and localizing of an intramedullary hematoma. Beside the clear limitations of our study, it could result in a novel application of the aforementioned monitoring technique.

Objective: D-wave can safely monitor the corticospinal-tract (CST)-function regarding gross-motor outcome of lower extremities, but it is still unknown whether i)D-wave can also safely monitor the gross-motor outcome of distal upper extremities in those patients undergoing high-cervical intramedullary-spinal-cord-tumor (IMSCT)-resection (enabling epidural D-wave-placement below C5) and ii)multimodal IONM can also predict fine-motor/complex hand function., Methods: We prospectively assessed 20 patients undergoing IMSCT-surgery above the C4/5-level with multimodal IONM (D-wave/mMEPs/EMG/SSEPs). Detailed gross-/fine-motor and complex hand function was assessed pre- and postoperatively and during long-term follow-up (mean:29.5 ± 18.8 months) and correlated with IONM-findings., Results: D-wave monitoring was without intraoperative critical changes in all patients and none had any permanent postoperative gross-motor deficits. However, D-wave did not allow to predict the occurrence of mild permanent postoperative deficits affecting fine-motor function which was the case in 8% for distal upper extremities. The complex distal upper extremities' function assessed by Nine-Hole-Peg-Test (reflecting the complex motor/sensory interaction for hand-usability) was permanently deteriorated in 15% postoperatively and only the combination of D-wave/mMEPs/EMG/SSEPs was able to provide a viable predictive power (specificity:79%/sensitivity:43%)., Conclusions: In high-cervical IMSCT-surgery, unimpaired D-wave reliably predicts preserved gross-motor function, but fails to sufficiently cover distal upper extremities' fine-motor/complex function., Significance: Our study underlines the importance of multimodal IONM for fine-motor/complex hand function., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Study Design: Retrospective observational study. Purpose: To evaluate intraoperative neurophysiological monitoring techniques in lumbosacral (L1-S1) pedicle screw placement surgery in University Medical Center Ho Chi Minh City, Vietnam. Overview of Literature: Intraoperative neurophysiological monitoring (IONM) in lumbosacral pedicle screw placement surgery helps the neurosurgeon detect early warning signs, reducing or preventing permanent postoperative neurological deficits. Methods: The authors carried out a retrospective study of 120 consecutive patients who underwent lumbosacral pedicle screw placement surgery and monitored neurophysiological intraoperative between May 2020 and December 2020, at the University Medical Center Hospital in Ho Chi Minh City, Viet Nam. Clinical assessment before and after surgery, intraoperative neurophysiological changes in Raw electromyogram (rEMG), somatosensory evoked potential (SSEP), triggered electromyogram (tEMG), pedicle screw testing (PED) were collected to calculating for sensitivity, specificity, positive predictive value, and negative predictive value of these techniques. Results: Of the 120 patients, 6 (5%) had postoperative new neurological deficits, of which a total of 666 pedicle screws were placed. The sensitivity and specificity of intraoperative rEMG monitoring in detecting postoperative nerve deficits were 83.3%, and 41.8%, respectively. The sensitivity and specificity of intraoperative SSEP monitoring in detecting postoperative nerve deficits were 50.0%, and 94.7%, respectively. The sensitivity of tEMG and PED were equal to 66.7%. The specificity of tEMG and PED were 85.4% and 98.1%, respectively. The positive predictive value of rEMG, SSEP, tEMG and PED were 10%, 33.3%, 21.1% and 66.7%, respectively. The negative predictive value of rEMG, SSEP, tEMG and PED were 98.6%, 97.2 %, 97.8% and 98.1%, respectively. Conclusions: rEMG has a high sensitivity (83.3%) in detecting postoperative nerve deficits. In opposite, SSEP, tEMG, PED have high specificity. These techniques help to predict and possibly prevent postoperative neurologic deficits in lumbosacral pedicle screw placement surgery.

Introduction: Interlaminar Endoscopic Lumbar Disckectomy has been found to offer symptomatic alleviation comparable to open disckectomy while reducing blood loss, postoperative discomfort, complications, hospital stay, and narcotic use. General anesthesia decreases intraoperative stress, but surgeons may not be sure whether they injure nerve roots. Free-run electromyography may protect nerve roots that are thought to be in danger from surgery. Methods: Patients with L4L5 or L5S1 lumbar disc herniation were treated with IELD. EMG was monitored via needle electrodes in lateral vastus lateralis, anterior tibialis, abductor hallucis muscles. Surgeons were asked to halt the surgery and adjust their manipulation right when abnormal EMG appeared on the screen. The severity of signs and symptoms were noted pre- and post-operatively. Results: In all 26 cases, the median of visual analogue scale (VAS) of low back pain was 4.5. That of radicular pain was 7. Two patients had motor weakness at L4 or S1 muscles. One patient has sensory loss at L5 dermatome. The level of disc herniation was 46% at L4L5 and 56% at L5S1. The complications included only superficial infection in two patients that were effectively managed with antibiotics. During postoperative follow-up, all patients recovered completely without any neurological deficit. f-EMG signal included uneventful (9 patients), burst/spike (10 patients), A-train (3 patients, and C-train (4 patients) Conclusion: Free-run EMG is a protective mean in IELD. All surgeons will profit from this technique in the early stages of their learning curve. To examine the outcomes, further comparative research and prospective, randomized, controlled trials should be undertaken.

Objective: This study aimed to investigate the value of intraoperative neurophysiological monitoring (IONM) in anterior cervical spine discectomy with fusion (ACDF) for ossification of the posterior longitudinal ligament (OPLL). Methods: Patients who underwent multimodal IONM (transcranial electrical motor-evoked potentials [tcMEP], somatosensory-evoked potentials, and continuous electromyography) for ACDF from 2009 to 2019 were compared to historical controls from 2003 to 2009. The rates of postoperative neurological deficits, neurophysiological warnings, and their characteristics were analyzed. Results: Among 196 patients, postoperative neurological deficit rates were 3.79% and 14.06% in the IONM and historical control (non-IONM) groups, respectively (p

Background: Spinal cord ischemia (SCI) is a potentially devastating complication of thoracic endovascular aortic repair (TEVAR) and fenestrated-branched endovascular aortic repair (F-BEVAR). The aim of this systematic review was to evaluate the efficacy of neuromonitoring modalities to mitigate the risk of SCI during TEVAR and F-BEVAR procedures., Methods: Following the PRISMA guidelines, we conducted a detailed literature search of databases including PubMed, MEDLINE via Ovid, Embase, Scopus, and Cochrane CENTRAL, from 1998 to the present. Inclusion criteria were original research articles examining neuromonitoring during TEVAR and F-BEVAR. The primary outcome was the incidence of SCI, while the secondary outcome included early mortality. The quality of studies was assessed using the Newcastle-Ottawa Scale., Results: From 1,450 identified articles, 11 met inclusion criteria, encompassing data from 1,069 patients. Neuromonitoring modalities included motor-evoked potentials (MEPs), somatosensory evoked potentials (SSEPs), and near-infrared spectroscopy. The combination of MEPs and SSEPs was most commonly used, with 93% sensitivity and 96% specificity for detecting SCI risks. SCI incidence ranged from 3.8 to 17.3%, with permanent deficits occurring in 2.7-5.8% of cases. In-hospital mortality ranged from 0.4 to 8%. Risk factors for SCI were identified, including operation duration and extent of aortic coverage., Conclusions: Neuromonitoring with MEPs and SSEPs appears to be effective in detecting perioperative SCI risk during TEVAR and F-BEVAR. However, discrepancies between neuromonitoring changes and actual SCI outcomes suggest the need for cautious interpretation. While the incidence of SCI remains variable, identified risk factors may guide clinical decisions, particularly in high-risk procedures. Future research should focus on prospective studies and randomized controlled trials to validate these findings and improve SCI prevention strategies in TEVAR and F-BEVAR., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objective: In this study, we present the first 12 cases of the use of intraoperative neurophysiological monitoring (IONM) during therapeutic epiduroscopy in patients with clinical canal stenosis. Methods: IESS was performed using two working instruments: an epidural balloon to dilate the epidural space without damaging the nerve structures (Resaloon®) and an element to perform flavotomy of the ligamentum flavum (Resaflex®). The procedure was performed at levels of the greatest stenosis, as detected using preoperative magnetic resonance imaging. Results: Of the 12 cases that used IONM, 2 patients presented neurotonic activity in roots during ligamentum flavum ablation, 1 patient presented neurotonic activity while using Resaloon® in a root contralateral to the level at which the procedure was conducted, and other presented neurotonic activity in a root below the level at which the ligamentum flavum was ablated. In all cases, potentially harmful discharges stopped when the procedure was interrupted momentarily. Conclusions: Intraoperative neurophysiological monitoring detected alterations in surgical field and roots below and/or contralateral to the field, which disappeared with complete recovery after interrupting the procedure; this can avoid the possible prolonged or even permanent complications postoperatively. Significance: Intraoperative neurophysiological monitoring during epiduroscopy is safe, thus optimizing surgical outcomes.

Objective: To determine the utility of electroencephalography (EEG) in predicting postoperative delirium (POD) in patients who underwent cardiovascular surgeries with EEG monitoring., Methods: A total of 1161 patients who underwent cardiovascular surgeries with EEG monitoring were included in the study, and their data were retrospectively reviewed. POD assessment was done utilizing Intensive Care Delirium Screening Checklist (ICDSC). Patients with a score of > 4 on ICDSC were diagnosed with POD., Results: Of 1161 patients, 131 patients had EEG changes and 56 (42.74%) of 131 patients experienced POD. Of 1030 patients without EEG changes, 219 (21.26%) experienced POD. EEG showed specificity of 91.5% and negative predictive value of 78.7% in detecting POD. On multivariable analysis, EEG changes showed a strong association with POD (OR adj 1.97 CI (1.30-2.99), p = 0.001) with persistent EEG changes showing even a higher risk of developing POD (OR adj 2.65 (1.43-4.92), p = 0.002)., Conclusion: EEG change has specificity of 91.5% emphasizing the need for its implementation as a diagnostic tool for predicting POD. Patients with POD are two times more likely to experience significant EEG changes, especially persistent EEG changes when undergoing cardiovascular surgeries., Significance: Intraoperative EEG can detect POD, and EEG changes based therapeutic interventions can mitigate POD., (Copyright © 2024 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: To analyze the feasibility, neurophysiological aspects, stimulation patterns, and topographic distribution of trigemino-cervical reflex (TCR) components in humans under general anesthesia., Methods: This prospective observational study enrolled 20 participants who underwent posterior fossa surgery, surgical proceduresin thecraniovertebral junction,or spinal cord surgery. TCR responses were simultaneously recorded in the sternocleidomastoid (SCM) and trapezius muscles after electrical stimulation of the supraorbital and infraorbital nerves. TCR responses were recorded preoperatively and intraoperatively using single-pulse and multipulse (trains of 2-7 electrical stimuli) stimulation, respectively. Two stimulus duration patterns were evaluated: 0.2-0.5 ms and 0.5-1.0 ms., Results: Intraoperatively, short- and long-latency TCR components were obtained in the SCM ipsilateral to the stimulation with variable recordability. Short-latency responses were the most commonly recorded components. A longer stimulus duration (0.5-1.0 ms) seems to favor the elicitation of TCR responses under general anesthesia., Conclusions: Short-latency components recorded in the SCM ipsilateral to the stimulation could be regularly elicited under general anesthesia when a larger stimulus duration (0.5-1.0 ms) was applied., Significance: This is the first study to demonstrate the elicitation of TCR components in humans under general anesthesia. This neurophysiological technique can potentially optimize intraoperative neurophysiological monitoring during brainstem surgery., (Copyright © 2024 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: We investigated the feasibility of recording cortico-cortical evoked potentials (CCEPs) in patients with low- and high-grade glioma. We compared CCEPs during awake and asleep surgery, as well as those stimulated from the functional Broca area and recorded from the functional Wernicke area (BtW), and vice versa (WtB). We also analyzed CCEP properties according to tumor location, histopathology, and aphasia., Methods: We included 20 patients who underwent minimally invasive surgery in an asleep-awake-asleep setting. Strip electrode placement was guided by classical Penfield stimulation of positive language sites and fiber tracking of the arcuate fascicle. CCEPs were elicited with alternating monophasic single pulses of 1.1 Hz frequency and recorded as averaged signals. Intraoperatively, there was no post-processing of the signal., Results: Ninety-seven CCEPs from 19 patients were analyzed. There was no significant difference in CCEP properties when comparing awake versus asleep, nor BtW versus WtB. CCEP amplitude and latency were affected by tumor location and histopathology. CCEP features after tumor resection correlated with short- and long-term postoperative aphasia., Conclusion: CCEP recordings are feasible during minimally invasive surgery. CCEPs might be surrogate markers for altered connectivity of the language tracts., Significance: This study may guide the incorporation of CCEPs into intraoperative neurophysiological monitoring., (Copyright © 2024 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Competing Interests: The authors declare that they have no conflicts of interest.

Objective: To evaluate the clinical value of intraoperative nerve monitoring (IONM) for dysphagia after anterior cervical surgery with and without IONM., Methods: A prospective, randomized, controlled study was conducted on 46 patients who underwent anterior cervical spine surgery by an experienced orthopaedic surgeon. Twenty-three patients who underwent anterior cervical surgery did not undergo IONM (non-IONM group), while the other 23 patients who underwent anterior cervical surgery did ("IONM group"). The swallowing function of patients was evaluated using the EAT-10 and endoscopic evaluation of swallowing (FEES) after surgery., Results: There was no difference in the incidence of swallowing difficulties between the intervention group and the control group on the third day or sixth week after surgery. At the 12th week after surgery, the incidence of swallowing difficulties in the intervention group and the control group was significantly different (43.5% vs. 13.0%, P = 0.024)., Conclusions: IONM is a promising tool for identifying and protecting the spinal cord and nerves during anterior cervical surgery. Our research revealed that IONM significantly reduced the occurrence of swallowing disorders 12 weeks after surgery, but the effect was not significant at the third or sixth week after surgery., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Syringomyelia is a well-known spinal cord pathology characterized by an intramedullary cyst that is often chronic and can be progressive. The earliest techniques of syrinx decompression began with simple aspiration after laminectomy and predated anatomic imaging. This was followed by early attempts at keeping communication open between the syrinx and the subarachnoid space using various materials as conduits, essentially creating the first attempts at syringo-subarachnoid shunting (SSS). Even in the modern era of high-quality anatomic imaging with MRI and use of modern materials as implants, novel ways to maintain communication between a syrinx cavity and the subarachnoid space continue to be reported. Methods: A total of 212 patients with imaging-proven syringomyelia presented to our center between 2014 and 2019 and were retrospectively reviewed. The majority of these patients (197) had an identifiable primary cause and surgical treatment was directed at the underlying condition. A total of 18 patients had a T-tube style SSS placed at our center using a K-tube shunt. The mean follow-up was 31.5 months, mean age was 38 years (2–59). The European Myelopathy Score (EMS) and Chicago Chiari Outcome Scale (CCOS) were used to categorize outcomes and progress in these 18 patients. Also we report clinical case to demonstrate technique of K-tube use for syringo-subarachnoid shunting and potential abilities of inner syrinx cyst videoscopy for treatment of syringomyelia in 2-year-old patient with multiple congenital vertebral and spinal cord abnormality. Results: Among 16 patients available for follow-up 4 patients (25%) had neurological improvement, 12 patients (75%) remained clinically stable, and no patient had a neurological deterioration based on EMS. Using the CCOS 8 patients (50%) improved, 7 patients (44%) remained stable, and 1 patient (6%) worsened during in the follow-up period. Complications occurred in six patients (33%). Two patients had gait ataxia. Two patients developed postoperative meningitis treated successfully with antibiotics leaving the shunt in place. One patient had a CSF leak successfully treated with a lumbar drain. One patient developed a new pain syndrome. There was no mortality, shunt migration/malposition or reoperation. Conclusions: Syringo-subarachnoid shunting is a well-known and well-described procedure used as “second-line” treatment of syringomyelia worldwide. Our results are consistent with others and make this another surgical option if treatment of a primary source fails or no primary source of the syrinx is found. Our series of 18 patients using a T-tube style SSS adds another good option to those already in use. Recurrence or deterioration following syringomyelia shunting remains a problem and further refinement of technique remains an ongoing process. Syrinx inner videoscopy seems to be safe procedure with possible application to simplify the anatomy of cyst and liquid flow relief.

Lumbar spinal stenosis (LSS) is defined as a degenerative disorder showing a narrowing of the spinal canal. The diagnosis is straightforward in cases with typical neurogenic claudication symptoms and unequivocal imaging findings. However, not all patients present with typical symptoms, and there is obviously no correlation between the severity of stenosis and clinical complaint. The radiologic diagnosis of LSS is widely discussed in the literature. The best diagnostic test for the diagnosis of LSS is magnetic resonance imaging (MRI). However, canal diameter measurements have not gained much consensus from radiologists, whereas qualitative measures, such as cerebrospinal fluid space obliteration, have achieved greater consensus. Instability can best be defined by standing lateral radiograms and flexion-extension radiograms. For cases showing typical neurogenic claudication symptoms and unequivocal imaging findings, the diagnosis is straightforward. However, not all patients present with typical symptoms, and there is obviously no correlation between the severity of stenosis (computed tomography and MRI) and clinical complaint. In fact, recent MRI studies have shown that mild-to-moderate stenosis can also be found in asymptomatic individuals. Routine electrophysiological tests such as lower extremity electromyography, nerve conduction studies, F-wave, and H-reflex are not helpful in the diagnosis and outcome prediction of LSS. The electrophysiological recordings are complementary to the neurologic examination and can provide confirmatory information in less obvious clinical complaints. However, in the absence of reliable evidence, imaging studies should be considered as a first-line diagnostic test in the diagnosis of degenerative LSS.

Background: Transsulcal tubular retractor-assisted minimally invasive parafascicular surgery changes the surgical strategy for deep-seated lesions by promoting a deficit-sparing approach. When integrated with preoperative brain mapping and intraoperative neuromonitoring (IONM), this approach may potentially improve patient outcomes. In this study, we assessed the impact of preoperative brain mapping and IONM in tubular retractor-assisted neuro-oncological surgery., Methods: This retrospective single-center cohort study included patients who underwent transsulcal tubular retractor-assisted minimally invasive parafascicular surgery for resection of deep-seated brain tumors from 2016 to 2022. The cohort was divided into 3 groups: group 1, no preoperative mapping or IONM (17 patients); group 2, IONM only (25 patients); group 3, both preoperative mapping and IONM (38 patients)., Results: We analyzed 80 patients (33 males and 47 females) with a median age of 46.5 years (range: 1-81 years). There was no significant difference in mean tumor volume (26.2 cm 3 [range 1.07-97.4 cm 3 ]; P = 0.740) and mean preoperative depth of the tumor (31 mm [range 3-65 mm], P = 0.449) between the groups. A higher proportion of high-grade gliomas and metastases was present within group 3 (P = 0.003). IONM was related to fewer motor (P = 0.041) and language (P = 0.032) deficits at hospital discharge. Preoperative mapping and IONM were also related to shorter length of stay (P = 0.008)., Conclusions: Preoperative and intraoperative brain mapping and monitoring enhance transsulcal tubular retractor-assisted minimally invasive parafascicular surgery in neuro-oncology. Patients had a reduced length of stay and prolonged overall survival. IONM alone reduces postoperative neurological deficit., (Crown Copyright © 2023. Published by Elsevier Inc. All rights reserved.)

Introduction: Dorsal root ganglion stimulation (DRG-S) is a viable interventional option for intractable pain management. Although systematic data are lacking regarding the immediate neurologic complications of this procedure, intraoperative neurophysiological monitoring (IONM) can be a valuable tool to detect real-time neurologic changes and prompt intervention(s) during DRG-S performed under general anesthesia and deep sedation., Materials and Methods: In our single-center case series, we performed multimodal IONM, including peripheral nerve somatosensory evoked potentials (pnSSEPs) and dermatomal somatosensory evoked potentials (dSSEPs), spontaneous electromyography (EMG), transcranial motor evoked potentials (MEPs), and electroencephalogram (EEG) for some trials and all permanent DRG-S lead placement per surgeon preference. Alert criteria for each IONM modality were established before data acquisition and collection. An IONM alert was used to implement an immediate repositioning of the lead to reduce any possible postoperative neurologic deficits. We reviewed the literature and summarized the current IONM modalities commonly applied during DRG-S, including somatosensory evoked potentials and EMG. Because DRG-S targets the dorsal roots, we hypothesized that including dSSEP would allow more sensitivity as a proxy for potential sensory changes under generalized anesthesia than would including standard pnSSEPs., Results: From our case series of 22 consecutive procedures with 45 lead placements, one case had an alert immediately after DRG-S lead positioning. In this case, dSSEP attenuation was seen, indicating changes in the S1 dermatome, which occurred despite ipsilateral pnSSEP from the posterior tibial nerve remaining at baselines. The dSSEP alert prompted the surgeon to reposition the S1 lead, resulting in immediate recovery of the dSSEP to baseline status. The rate of IONM alerts reported intraoperatively was 4.55% per procedure and 2.22% per lead (n = 1). No neurologic deficits were reported after the procedure, resulting in no postoperative neurologic complications or deficits. No other IONM changes or alerts were observed from pnSSEP, spontaneous EMG, MEPs, or EEG modalities. Reviewing the literature, we noted challenges and potential deficiencies when using current IONM modalities for DRG-S procedures., Conclusions: Our case series suggests dSSEPs offer greater reliability than do pnSSEPs in quickly detecting neurologic changes, and subsequent neural injury, during DRG-S cases. We encourage future studies to focus on adding dSSEP to standard pnSSEP to provide a comprehensive, real-time neurophysiological assessment during lead placement for DRG-S. More investigation, collaboration, and evidence are required to evaluate, compare, and standardize comprehensive IONM protocols for DRG-S., (Copyright © 2023 International Neuromodulation Society. Published by Elsevier Inc. All rights reserved.)

Background: In treating anterior choroidal artery (AChA) aneurysms, preserving the AChA main trunk is of course necessary to prevent postoperative ischemic complications. However, in practice, complete occlusions are often limited by small branches., Objective: We aimed to demonstrate that even in cases where complete occlusion of the AChA aneurysm is complex due to small branches, complete occlusion can be safely achieved using indocyanine green video-angiography and intraoperative neurophysiological monitoring (IONM)., Methods: We performed a retrospective review of all unruptured AChA aneurysms surgically treated at our institution from 2012 to 2021. All available surgical videos were reviewed to find AChA aneurysms clipped with small branches; clinical and radiological data were collected for these cases., Results: Among 391 cases of unruptured AChA aneurysms treated surgically, 25 AChA aneurysms were clipped with small branches. AChA-related ischemic complications occurred in 2 cases (8%) without retrograde indocyanine green filling to the branches. These 2 cases had changes in IONM. There were no ischemic complications in the remaining cases with retrograde indocyanine green filling to the branches and no change in IONM. During an average follow-up of 47 months (12-111 months), a small residual neck was observed in 3 cases (12%) and recurrence or progression of the aneurysm was observed in only 1 case (4%)., Conclusions: The surgical treatment of AChA aneurysms carries the risk of devastating ischemic complications. Even in cases where complete clip ligation seems impossible due to small branches associated with AChA aneurysms, complete occlusion can be safely achieved using indocyanine green video-angiography and IONM., (Copyright © 2023. Published by Elsevier Inc.)

Objectives: This study aims to describe the state of literature regarding the use of intraoperative neurophysiological monitoring (IONM) during spinal cord stimulator surgery., Materials and Methods: A systematic review of the use of IONM during spinal cord stimulation (SCS) surgery was performed using the following three data bases: PubMed, Ovid MEDLINE, and Embase. Research techniques included systematic research following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol by Cochrane, and backward searching. Qualitative analysis of included articles was performed using the methodologic index for nonrandomized studies assessment tool. Direction of effect, consistency across studies, and cost-effectiveness were narratively synthesized., Results: A total of 15 records were identified through data base searching. All records used IONM methods under general anesthesia for guidance of epidural lead placement. IONM techniques used for determining lateralization in the found articles were compound muscle action potentials (CMAPs) (n = 8), somatosensory evoked potentials (SSEPs) (n = 3) or both (n = 4). Motor evoked potentials were used in three trials for neuroprotection purposes. Two studies were comparative, and 12 were noncomparative., Conclusions: We found a good body of level II evidence that using IONM during SCS surgery is a valid alternative to awake surgery and may even be superior regarding pain management, cost-effectiveness, and postoperative neurologic deficits. In direct comparison, the found evidence suggested using CMAP provided more consistently favorable results than using SSEP for midline placement of epidural leads under general anesthesia. Selection of IONM modality should be made on the basis of pathophysiology of disease, individual IONM experience, and the individual patient., Competing Interests: Conflict of Interest Janine-Ai Schlaeppi is a consultant for Abbott and Nevro. Claudio Pollo is cofounder of Aleva Neurotherapeutics and reports consultancy fees from Boston Scientific and Abbott in the field of deep brain stimulation. Raphael Schreen and Kathleen Seidel reported no conflict of interest. Stimulation parameters are listed as far as specified in the publication., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: To identify the incidence and predictors of postoperative dysphagia in patients who undergo anterior cervical spine surgery (ACSS) by utilizing the Eating Assessment Tool (EAT-10)., Methods: A multicenter prospective study was undertaken at three hospitals to evaluate patients undergoing ACSS between January 2021 and January 2023. Included patients were aged 18-80 years and were undergoing primary or revision ACSS. Dysphagia was assessed using the validated EAT-10 questionnaire. Patients with dysphagia were included in the observation group, and those without dysphagia were included in the control group., Results: Of the 343 patients enrolled, 50 patients (14.6%) had EAT-10 scores of 3 or more at the 6-month follow-up. In the univariate analysis, patients with dysphagia at 7 days had a longer operative time, were current smokers, had involvement of vertebral bodies at C4 and above, and underwent intraoperative neurophysiological monitoring. Patients with dysphagia at 6 months had involvement of vertebral bodies at C4 and above and underwent intraoperative neurophysiological monitoring. In the multivariate analysis to determine associations with prolonged dysphagia, only the involvement of vertebral bodies at C4 and above (odds ratio 3.883, 95% confidence interval 1.847-8.165, P = 0.001) and intraoperative neurophysiological monitoring (odds ratio 0.273, 95% confidence interval 0.080-0.931, P = 0.038) remained significant., Conclusions: Dysphagia is common after ACSS, affecting more than 67.5% of patients at 7 days postoperatively, but over time, the incidence of dysphagia gradually decreases. Involvement of the vertebral bodies at C4 and above is a risk factor for dysphagia after ACSS, and intraoperative neurophysiological monitoring is a protective factor., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: Intraoperative neurophysiological monitoring (IONM) was investigated as a complex intervention (CI) as defined by the United Kingdom Medical Research Council (MRC) in published studies to identify challenges and solutions in estimating IONM's effects on postoperative outcomes., Methods: A scoping review to April 2022 of the influence of setting on what was implemented as IONM and how it influenced postoperative outcomes was performed for studies that compared IONM to no IONM cohorts. IONM complexity was assessed with the iCAT&#95;SR tool. Causal graphs were used to represent this complexity., Results: IONM implementation depended on the surgical procedure, institution and/or surgeon. "How" IONM influenced neurologic outcomes was attributed to surgeon or institutional experience with the surgical procedure, surgeon or institutional experience with IONM, co-interventions in addition to IONM, models of IONM service delivery and individual characteristics of the IONM provider. Indirect effects of IONM mediated by extent of tumor resection, surgical approach, changes in operative procedure, shorter operative time, and duration of aneurysm clipping were also described. There were no quantitative estimates of the relative contribution of these indirect effects to total IONM effects on outcomes., Conclusions: IONM is a complex intervention whose evaluation is more challenging than that of a simple intervention. Its implementation and largely indirect effects depend on specific settings that are usefully represented in causal graphs., Significance: IONM evaluation as a complex intervention aided by causal graphs and multivariable analysis could provide a valuable framework for future study design and assessments of IONM effectiveness in different settings., (Copyright © 2023 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)