Background: Monitoring the electroencephalogram (EEG) during general anesthesia can help to safely navigate the patient through the procedure by avoiding too deep or light anesthetic levels. In daily clinical practice, the EEG is recorded from the forehead and available neuromonitoring systems translate the EEG information into an index inversely correlating with the anesthetic level. Electrode placement on the forehead can lead to an influence of electromyographic (EMG) activity on the recorded signal in patients without neuromuscular blockade (NMB). A separation of EEG and EMG in the clinical setting is difficult because both signals share an overlapping frequency range. Previous research showed that indices decreased when EMG was absent in awake volunteers with NMB. Here, we investigated to what extent the indices changed, when EEG recorded during surgery with NMB agents was superimposed with EMG.
Methods: We recorded EMG from the flexor muscles of the forearm of 18 healthy volunteers with a CONOX monitor during different activity settings, that is, during contraction using a grip strengthener and during active diversion (relaxed arm). Both the forehead and forearm muscles are striated muscles. The recorded EMG was normalized by z -scoring and added to the EEG in different amplification steps. The EEG was recorded during anesthesia with NMB. We replayed these combined EEG and EMG signals to different neuromonitoring systems, that is, bispectral index (BIS), CONOX with qCON and qNOX, and entropy module with state entropy (SE) and response entropy (RE). We used the Friedman test and a Tukey-Kramer post hoc correction for statistical analysis.
Results: The indices of all neuromonitoring systems significantly increased when the EEG was superimposed with the contraction EMG and with high EMG amplitudes, the monitors returned invalid values, representative of artifact contamination. When replaying the EEG being superimposed with "relaxed" EMG, the qCON and BIS showed significant increases, but not SE and RE. For SE and RE, we observed an increased number of invalid values.
Conclusions: With our approach, we could show that EMG activity during contraction and resting state can influence the neuromonitoring systems. This knowledge may help to improve EEG-based patient monitoring in the future and help the anesthesiologist to use the neuromonitoring systems with more knowledge regarding their function.
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http://dx.doi.org/10.1213/ANE.0000000000006652 | DOI Listing |
BMC Musculoskelet Disord
December 2024
Department of Orthopaedics, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China.
Background: A warning system to avoid potential nerve root thermal injury caused by automatic spine robot is essential. However, there is a lack of basic research to support the development of such warning system. The aims of this study are to confirm the feasibility of continuous intraoperative neuromonitoring (CIONM) in spinal nerve root monitoring and study the exposure time of spinal nerve root thermal injury at different temperature in a porcine model.
View Article and Find Full Text PDFNeurol India
November 2024
Department of Neurosurgery, Jawaharlal Institute of Post-graduate Medical Education and Research (JIPMER), Gorimedu, Puducherry, India.
Background And Aim: Despite the sustained progress in the realm of intraoperative neurophysiologic monitoring of the nervous system, little progress has been achieved in monitoring the olfactory pathway. Loss of olfactory function due to retraction-induced physical damage during operations has ill-appreciated negative consequences for the patients and is often underreported. Improvements in this area of neuromonitoring require a revisit of the technical challenges.
View Article and Find Full Text PDFActa Neurochir (Wien)
December 2024
Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke Hospital, University of Cambridge, Cambridge, UK.
Background: Traumatic brain injury (TBI) can significantly disrupt autonomic nervous system (ANS) regulation, increasing the risk for secondary complications, hemodynamic instability, and adverse outcome. This retrospective study evaluated windowed time-lagged cross-correlation (WTLCC) matrices for describing cerebral hemodynamics-ANS interactions to predict outcome, enabling identifying high-risk patients who may benefit from enhanced monitoring to prevent complications.
Methods: The first experiment aimed to predict short-term outcome using WTLCC-based convolution neural network models on the Wroclaw University Hospital (WUH) database (P = 31 with 1,079 matrices, P = 16 with 573 matrices).
J Korean Neurosurg Soc
December 2024
Department of Neurosurgery, Wonkwang University Hospital, Institute of Wonkwang Medical Science, Iksan, Korea.
Objective: In 2006, the Korean Neurotraumatology Society (KNTS) established the 1st Korean Neurotrauma Data Bank Committee (KNTDBC) and developed the Korean Neurotrauma Data Bank System (KNTDBS). Full-scale registration of traumatic brain injury (TBI) patient data began in September 2010. Since then, KNTS has conducted two trauma-related data registration projects and is now in its 5th term of the KNTDBC.
View Article and Find Full Text PDFEur Spine J
December 2024
Department of Orthopaedic Surgery, Seattle Children's Hospital, University of Washington, 4800 Sand Point Way NE, Seattle, WA, 98105, USA.
Purpose: Intraoperative traction can improve deformity correction during posterior spinal fusion (PSF). This is commonly done with invasive distal femoral or pelvic pins, or traction boots. The novel technique of intraoperative skin traction (ISkinT) avoids risks associated with intraoperative skeletal traction (ISkelT) or hyperlordosis with extended hip position.
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