Search

Contingency data was retrospectively collected to evaluate the historical and current ability to provide multimodality intraoperative neurophysiological monitoring during carotid endarterectomy under two conditions: total intravenous anaesthesia (TIVA) and low dose halogenated anaesthesia (SEVO). 229 patients were monitored during carotid endarterectomy procedures under general anaesthesia between 2012 and 2020. 121 Patients were monitored with SEVO at a minimum alveolar concentration less than 0.7 and 108 were monitored using TIVA, according to common anaesthetic practice standards in our hospital across the years. Multimodality IONM was established with electroencephalography, somatosensory evoked potentials and motor evoked potentials. As compared to TIVA, patients monitored with SEVO showed significantly higher motor evoked potential thresholds (313.52 ± 77.74 SEVO and 218.93 V ± 103.2 V TIVA p

Objective To evaluate cylindrical depth electrodes in the interhemispheric fissure as an alternative to subdural strip electrodes for direct cortical stimulation (DCS) leg motor evoked potential (MEP) monitoring. Methods A cylindrical depth electrode was positioned in the interhemispheric fissure of 37 patients who underwent supratentorial brain surgery. Leg sensory and motor cortices were localized by highest tibial nerve somatosensory evoked potential amplitude and lowest DCS leg MEP threshold; the lowest-threshold electrode was then used for DCS leg MEP monitoring. Results Intraoperative leg MEPs were obtained from all the patients in the series. The mean intensity applied for leg MEP monitoring with the cylindrical depth electrode was 15.2 ± 4.0 mA. No complications secondary to neurophysiological monitoring were detected. Conclusions Lower extremity MEPs were consistently recorded using a multi-contact cylindrical depth electrode in the interhemispheric fissure by DCS. Significance Cylindrical depth electrodes may be a safe and effective alternative for DCS in the interhemispheric fissure, where subdural strips are difficult to place.

Droperidol is a D2 receptor antagonist currently used in Europe for preventing postoperative nausea and vomiting. It was used to perform neurolept anaesthesia in combination with fentanyl until a Food and Drug Administration (FDA) ‘black box’ warning restricted its use due to cardiovascular side effects in 2001. There is no literature regarding the effects of droperidol on transcranial motor evoked potentials (TcMEPs) elicited by electrical stimulation. Our aim was to report two cases of spine surgery in which TcMEPs were lost due to droperidol administration. We report the cases of a 4-year-old male with scoliosis undergoing correction and a 58-year-old woman with metastasis on the D8 vertebrae undergoing kyphosis correction. Intraoperative neurophysiological monitoring was achieved through TcMEPs and somatosensory evoked potentials (SEPs). Intraoperative neurophysiological monitoring (IONM) showed a temporal loss of TcMEPs without SEPs changes coinciding with the administration of droperidol. TcMEP stimulation parameters were changed to double train of pulses, with the aim to elicit them, obtaining responses. Five minutes after droperidol administration, TcMEPs were equal to those at baseline. Droperidol used as prophylaxis for postoperative nausea abolishes TcMEPs. Changing stimulation parameters to double train of pulses, it allows to bypass droperidol central action, achieving monitorable TcMEPs.

Background Intraoperative neurophysiological monitoring (IONM) with nerve action potential (NAP) can be useful during peripheral nerve surgery. However, current methodologies are not optimized for continuous recording of the NAP. The use of newer electrodes may make it possible to more conveniently obtain continuous recordings of the NAP during surgery. Methods After localizing the nerve of interest and dissecting it from the adjacent soft tissue, two APS® (Automatic Periodic Stimulation) electrodes, originally designed for stimulation of the vagus nerve during thyroid surgery, are placed on the nerve on either sides of the tumor for stimulation and recording using two subdermal electroencephalogram (EEG) needles as anode and reference, respectively. Both monopolar and bipolar recordings can be used as appropriate. Anesthesia regime comprised sevoflurane or total intravenous anesthesia (TIVA). No muscle relaxant after intubation, local anesthesia, or blood pressure cuff is used during the surgery. Results Twelve patients (6 male, 6 female) with peripheral nerve tumors (motor, sensitive, or mixed nerves) or tumors affecting the peripheral nerves were monitored in our center since 2014 (mean age: 50 years; 28-79). In 10 patients, the NAP was monitored without experiencing any changes from the beginning till the end of the surgery; in these patients, no postoperative deficit was adverted. In the last 2 patients, who departed from a complete neurological deficit, no NAP was recorded at the baseline or during the surgery, and they did not experience any neurological improvement. Conclusion The vagus nerve stimulation electrodes open new possibilities in peripheral nerve IONM. We have used them for continuous monitoring without additional problems with the traditional probes.