Intraoperative use of heads-up display in skull base surgery

In this video, the authors highlight the applications of virtual reality and heads-up display in skull base surgery by presenting the case of a 45-year-old woman with an incidental large clinoid meningioma extending into the posterior fossa. The patient underwent preoperative endovascular tumor embolization to facilitate tumor resection and reduce blood loss, followed by a right pterional craniotomy. The use of intraoperative Doppler, intraoperative neurophysiological monitoring, and endoscope-assisted microsurgery is also featured. A subtotal resection was planned given tumor encasement of the posterior communicating and anterior choroidal arteries. No new neurological deficits were noted after the surgical procedure. The video can be found here: https://stream.cadmore.media/r10.3171/2021.10.FOCVID21177

Evaluation of the effect of preoperative anxiety on intraoperative hemodynamic stability and drug consumption in patients who underwent BIS-guided total intravenous anesthesia (TIVA) for neurophysiological monitoring in spine surgery

In our study, the aim was to evaluate the effects of preoperative anxiety measured by Spielberger’s State-Trait Anxiety Inventory-State (STAI-S) and State-Trait Inventory-Trait (STAI-T) scores on intraoperative hemodynamic stability, drug consumption and recovery in patients who underwent spinal surgery with neurophysiological monitoring and total intravenous anesthesia with bispectral index (BIS) monitoring, without the use of muscle relaxants. Eighty patients with planned spinal surgery and neurophysiological monitoring were included in this prospective observational study. Anxiety scores were recorded by applying Spielberger’s STAI-T and STAI-S scoring questionnaires to all patients included in the study 1 hour before the operation. Age, gender and American Society of Anesthesiologists (ASA) scores of the patients who were taken to the operating table without premedication were recorded. Before anesthesia induction, standard monitoring including electrocardiography (ECG), noninvasive blood pressure, peripheral oxygen saturation (SpO2), BIS was applied. The correlation between STAI-T and STAI-S scores with demographic characteristics of patients, preoperative, post-induction, 5th minute, 10th minute, 30th minute, 50th minute, 70th minute, 90th minute heart rate (HR), mean arterial pressure (MAP), SpO2, operation time, recovery time, and total amount of propofol and remifentanil used during the operation were evaluated statistically. A significant negative correlation was observed between STAI-S anxiety scoring and age (p < 0.05). A significant positive correlation was found between the total amount of remifentanil and propofol used with the STAI-S score (p < 0.05). Significant positive correlations were observed between the STAI-S score and the HR value preoperatively, and in the 5th, 30th, 50th, 70th, and 90th minutes (p < 0.05). Our study showed that preoperative anxiety increases intraoperative drug consumption and heart rate. It is of great importance to keep the amount of intraoperative medication at optimal levels, to measure preoperative anxiety, and to eliminate it with multimodal treatments, especially for the accurate detection of neurological damage in patients with neurophysiological monitoring.

Impact of general anaesthesia on parameters of bulbocavernosus reflex

Dysfunction of the pelvic organs in tumor lesions of the spinal cord is up to 20%. Registration of the bulbocavernosus reflex is performed to assess the integrity of the segmental apparatus of the spinal cord. Polymodal neurophysiological monitoring includes registration of the bulbocavernosus reflex during surgery of spinal cord tumors. The effect of the components of general anesthesia on the parameters of the bulbocavernosus reflex varies significantly according to various medical sources. The aim of the work was to compare the effect of inhalation anesthesia (sevoflurane) and total intravenous anesthesia (propofol) on the parameters of the bulbocavernosus reflex in the surgical treatment of spinal cord tumors. Thirty patients with intradural extramedullary and intramedullary tumors of the spinal cord at the level of Th11–S2 vertebrae were included in the study. The amplitude-frequency parameters of the bulbocavernosus reflex and the threshold intensity of stimulation were assessed in the study. The results of the study demonstrate that intraoperative registration of the bulbocavernosus reflex during resection of tumors of the distal spinal cord can be performed both with inhalation and total intravenous anesthesia. A sustained motor response of the bulbocavernosus reflex requires a higher intensity of stimulation with inhalation anesthesia with sevoflurane than with total intravenous anesthesia. If during the operation the depth of propofol's anesthesia increases by 1 mg/kg/h, then it is necessary to increase the current strength during stimulation by 10–11 mA.

Electroencephalography Correlates of Well-Being Using a Low-Cost Wearable System

Electroencephalography (EEG) alpha asymmetry is thought to reflect crucial brain processes underlying executive control, motivation, and affect. It has been widely used in psychopathology and, more recently, in novel neuromodulation studies. However, inconsistencies remain in the field due to the lack of consensus in methodological approaches employed and the recurrent use of small samples. Wearable technologies ease the collection of large and diversified EEG datasets that better reflect the general population, allow longitudinal monitoring of individuals, and facilitate real-world experience sampling. We tested the feasibility of using a low-cost wearable headset to collect a relatively large EEG database (N = 230, 22–80 years old, 64.3% female), and an open-source automatic method to preprocess it. We then examined associations between well-being levels and the alpha center of gravity (CoG) as well as trait EEG asymmetries, in the frontal and temporoparietal (TP) areas. Robust linear regression models did not reveal an association between well-being and alpha (8–13 Hz) asymmetry in the frontal regions, nor with the CoG. However, well-being was associated with alpha asymmetry in the TP areas (i.e., corresponding to relatively less left than right TP cortical activity as well-being levels increased). This effect was driven by oscillatory activity in lower alpha frequencies (8–10.5 Hz), reinforcing the importance of dissociating sub-components of the alpha band when investigating alpha asymmetries. Age was correlated with both well-being and alpha asymmetry scores, but gender was not. Finally, EEG asymmetries in the other frequency bands were not associated with well-being, supporting the specific role of alpha asymmetries with the brain mechanisms underlying well-being levels. Interpretations, limitations, and recommendations for future studies are discussed. This paper presents novel methodological, experimental, and theoretical findings that help advance human neurophysiological monitoring techniques using wearable neurotechnologies and increase the feasibility of their implementation into real-world applications.

Treatment strategy for multisegmental cervicomedullary ependymoma: illustrative case

BACKGROUND Сervicomedullary ependymoma (CME) is a rare tumor of the central nervous system. The CME treatment strategy is insufficiently represented in the literature and is a complex task for neurosurgeons. OBSERVATIONS The authors describe an infrequent case of a large multisegmental CME that extended from the medulla oblongata to the cervical spinal cord at the level of the sixth cervical vertebra in a 21-year-old female. Neurological disorders presented with headache, dysphagia, hypophonia, and weakness in the limbs. Subtotal removal of the tumor was performed according to intraoperative neurophysiological monitoring (IONM) results. A wait-and-see approach with patient follow-up was chosen. LESSONS Total tumor removal of the CME is the most important favorable prognostic factor. Subtotal resection can be considered if the borders of the tumor are unclear and the result of IONM is unfavorable. The role of postoperative radiation therapy in the case of subtotal removal of the tumor remains controversial.

Roles of multimodal intra-operative neurophysiological monitoring (IONM) in percutaneous endoscopic transforaminal lumbar interbody fusion: a case series of 113 patients

Background Despite the wide use of intraoperative neurophysiological monitoring (IONM) in spinal surgeries, the efficacy of IONM during percutaneous endoscopic transforaminal lumbar interbody fusion (PE-TLIF) surgery in detecting postoperative neurological deficits has not been well characterized. Methods MIONM data from 113 consecutive patients who underwent PE-TLIF surgeries between June 2018 and April 2020 were retrospectively reviewed. Postoperative neurological deficits were documented and analyzed, and the efficacy and specificity of various IONM techniques were compared. Results Of the 113 consecutive patients, 12 (10.6%) with IONM alerts were identified. The MIONM sensitivity and specificity were 100 and 96.2%, respectively. The frequency of neurological complications, including minor deficits, was 6.2% (n = 7); all of the neurological complications were temporary. The ability of single IONM modalities to detect neurological complications varied between 25.0 and 66.6%, whereas that of all modalities was 100%. Conclusions MIONM is more effective and accurate than unimodal monitoring in assessing nerve root function during PE-TLIF surgeries, reducing both neurological complications and false-negative findings. We recommend MIONM in PE-TLIF surgeries.