OBJECTIVE: Spinal schwannomas (SS) and spinal meningiomas (SM) account for most intradural extramedullary (IDEM) tumors. These tumors are usually benign lesions, which generally respond favorably to surgical excision. Few studies up to now tried to determine the long-term outcome after minimally invasive surgery (MIS) with multimodal intraoperative neurophysiological monitoring (IONM) for IDEM tumors. The aim of this study was to present one of the largest case series with special regard to IONM findings and long-term outcome after MIS-keyhole surgery with a tubular retractor system.
METHODS: Between January 2013 and August 2018, 87 patients with IDEM tumors who underwent tumor removal surgery via MIS-keyhole approach under multimodal IONM were retrospectively reviewed. The neurological status was assessed using a modified McCormick grading scale pre- and postoperatively. Multimodal IONM consisted of motor evoked potentials (MEP), somatosensory evoked potentials (SEP), and electromyography (EMG). Both short-term and long-term clinical evaluations as well as patients\' medical files were retrospectively analyzed.
RESULTS: Surgeries were performed for resection of SS in 49 patients and SM in 38 patients. Tumor locations were cervical in 16.1%, thoracic in 48.3%, thoracolumbar in 4.6%, lumbar 31%. Critical IONM changes were detected in 9 operations (10.3%) in which there were 2 SEPs, 5 MEPs, and 2 EMG events. Three IONM changes (2 MEPs, 1 EMG) were turned out to be transient change in nature since they were resolved in a short time when immediate corrective actions were initiated. Six patients with permanent IONM changes (2SEPs, 3MEPs, 1EMG event), all deficits had resolved during hospitalization or on short -term follow-up evaluation. Sensitivity, specificity, and positive and negative predicted values of IONM were 100, 96, 67, and 100%, respectively. Gross total resection rate was 100%, and a stable or improved McCormick grade exhibited in all patients. No tumor recurrence and no spinal instability were found in the long-term follow-up evaluation (mean 5.2 ± 2.9 years postoperatively). Overall, 94% of patients were either satisfied or very satisfied with their operation, and 93% patients reported excellent or good general clinical outcome according to Odom\'s criteria.
CONCLUSIONS: MIS-keyhole surgery with multimodal IONM for IDEM tumors enables a high level of satisfaction and a satisfying long-term clinical and surgical outcome.

UNASSIGNED: Thyroid surgery is increasingly demanding in terms of cosmetic neck outcomes and protection of anterior neck function, so we have adopted an alternative sternocleidomastoid intermuscular approach (SMIA) for open/conventional thyroidectomy. The protection of recurrent laryngeal nerve (RLN) and external branch of superior laryngeal nerve (EBSLN) is the key and difficult point in thyroid surgery. The aim of this study was to testify the feasibility of RLN and EBSLN functional protection during SMIA thyroidectomy with the intraoperative neuromonitoring.
UNASSIGNED: A total of 39 patients and 39 RLN and EBSLNs who underwent monitored SMIA thyroidectomy were included. Thyroid gland is revealed and excised anterior to the cervical sheath between the sternal and clavicular heads of the sternocleidomastoid muscle. Standardized intraoperative neuromonitoring (IONM) procedures and postoperative laryngeal examination were performed to audit the SMIA. Following the four-step method, V1, R1, R2, and V2 were monitored and the signal values were recorded. Statistical analysis was used to evaluate the change of IONM amplitude of RLN, combined with the results of laryngoscopy before and after operation to determine the status of RLN. EBSLN injuries were identified from changes in cricothyroid muscle (CTM) twitch and EMG. SMIA video vignette is detailed.
UNASSIGNED: All RLN and EBSLNs [17 on the left and 22 on the right] were monitored in 39 patients [5 men, 34 women; mean age 34.1±8.7 years; mean body mass index 22.5 (±3.0, 17.0-30.8) kg/m2] undergoing SMIA. For RLN of the affected side, we compared the V2 and V1 (1,236±672 vs. 1,240±428, P=0.973), R2 and R1 (1,676±778 vs. 1,656±765, P=0.849) signals separately, and the results were not statistically different (P>0.05). Comparing the V1 (1,240±428 vs. 1,309±395, P=0.601) signals of the bilateral recurrent laryngeal nerve, there was no statistical difference (P>0.05). CTM twitch and EMG were preserved.
UNASSIGNED: The SMIA technique appears feasible. RLN and EBSLN are easier to be exposed during thyroid surgery of SMIA, which is beneficial to the neuroprotection during the operation. At the same time, it can protect the anterior cervical function and improve the cosmetic effect after operation.

To review our use of pharmacologic provocative testing (PT) and intraoperative neurophysiologic monitoring (IONM) during endovascular embolization for eloquent arteriovenous malformations (AVMs), and better define their clinical utility.
This is a prospective study between 1 June 2018 and 1 June 2020. Prior to endovascular embolization, superselective PTs with propofol injection were performed. The PT results were assessed by IONM. The impact of different doses of propofol on PT results was compared.
Under general anesthesia, 111 PTs and 48 endovascular embolizations were performed in 22 patients. For the initial 48 PTs before planned embolization, 38 PTs with 5 mg propofol were negative and repeat PTs with 7 mg propofol were also negative. For the remaining 10 positive PTs, the microcatheter tip was adjusted to an alternative site until repeat PTs were negative to ensure a subsequent safe embolization. In comparison, 5-mg-propofol PT results were consistent with 7-mg-propofol PTs in larger-sized feeders, whereas for smaller-sized vessels, 3-mg-propofol PT results were consistent with 5-mg-propofol PTs. The negative predictive value of PTs was 97.9% (47 of 48), as only 1 of the 48 embolizations with negative PTs resulted in postoperative hemorrhage and none of the other 47 embolizations led to a postoperative neurologic deficit.
PTs and IONM are valuable techniques to predict neurologic deficits and improve procedure decision-making during AVM embolization under general anesthesia. A 5-mg dose of propofol may be sufficient for PTs in larger-sized feeders and a 3-mg dose may be sufficient in smaller-sized feeding branches.

This study aimed to investigate the efficacy of intraoperative motor evoked potential (MEP) and somatosensory evoked potential (SSEP) monitoring for predicting postoperative motor deficits (PMDs) in patients with internal carotid artery (ICA) aneurysms. The data for 138 patients with ICA aneurysms who underwent surgical clipping as well as their intraoperative neuromonitoring data were retrospectively reviewed. The efficacy of MEP/SSEP changes for predicting PMDs was assessed using binary logistic regression analysis. Subsequently, receiver operating characteristic curve analysis was used to obtain a supplementary critical value of the MEP/SSEP deterioration duration. The sensitivity and specificity of MEP changes for predicting PMDs were 0.824 and 0.843, respectively. For SSEP changes, the sensitivity and specificity were 0.529 and 0.959, respectively. MEP and SSEP changes were identified as independent predictors for short-term (p = 0.002 and 0.011, respectively) and long-term PMDs (p = 0.040 and 0.006, respectively). The supplementary critical value for MEP deterioration duration for predicting PMDs was 14 min (p = 0.007, AUC = 0.805). For SSEP, the value was 14.5 min (p = 0.042, AUC = 0.875). The MEP/SSEP changes adjusted by those optimal values were also identified as independent predictors for short-term (p < 0.001 and p = 0.005, respectively) and long-term PMDs (p = 0.019 and 0.003, respectively). Intraoperative MEP and SSEP deterioration durations are effective in predicting PMDs in patients with ICA aneurysms.

OBJECTIVE: To evaluate long-term functional and survival outcomes of patients with glioma after intraoperative neurophysiologic monitoring (IONM) application.
METHODS: A total of 856 patients with glioma, who underwent tumor resection between October 2010 and March 2016, were included in this retrospective cohort study. All patients were stratified into IONM (439 patients) and non-IONM groups (417 patients). The primary outcome measured was overall survival (OS), and the secondary outcome measured was rate of late neurologic deficits. Analyses were performed using univariate tests and multivariate logistic regression and Cox proportional hazard model.
RESULTS: The 2 cohorts were well balanced with respect to baseline characteristics. Univariate survival analysis showed longer OS in the IONM group than that in the non-IONM group (P = 0.036), especially in patients with high-grade astrocytic tumor (P = 0.034). The IONM group showed a lower rate of neurologic deficits than did the non-IONM group. Multivariate analysis showed that IONM was a favorable factor of OS (odds ratio, 0.776; P = 0.046) and late neurologic function (odds ratio, 0.583; P = 0.039). Dominant hemispheric and eloquent location of glioma had no association with OS.
CONCLUSIONS: Application of IONM is beneficial to long-term functional and oncologic outcomes of patients with glioma.

The persistent primitive hypoglossal artery (PPHA) is the second most common persistent carotid-vertebrobasilar anastomosis, with an incidence of 0.027-0.26%. PPHAs change the hemodynamics of the carotid and vertebrobasilar system and may be associated with intracranial vascular anomalies, but basilar bifurcation aneurysms were rarely reported. We describe the first case of a PPHA as the sole supply to the brain associated with a basilar bifurcation aneurysm and review the literature. We reported a 34-year-old woman who presented with subarachnoid hemorrhage due to a ruptured basilar bifurcation aneurysm. Digital subtraction arteriogram revealed a right PPHA as the sole supply to the brain. The aneurysm was successfully clipped under intraoperative neurophysiology.