J of Neurophysiological Monitoring

Enhancing the Effectiveness of Monitoring the Robust Bulbocavernosus Reflex in Cauda Equina Surgeries: Harnessing Machine Learning to Decode the Complexity of Stimulation Parameters

2024-12-18T19:41:42+03:00

Cauda equina surgeries present significant challenges due to pathological diversity and anatomical variability, particularly in pediatric cases involving tethered spinal cord syndrome, lumbosacral spinal tumors, and congenital deformities. The Bulbocavernosus Reflex (BCR), mediated by the S2–S4 sacral segments, is an efficient multimodality intraoperative neurophysiological monitoring (IONM) tool for preserving sacral neural pathways during these complex procedures. Since its introduction in the IONM arena in the late 1990s, the efficacy of BCR in preventing pelvic neural deficits was gradually established. At the same time, advancements in IONM technology over the decades fostered its widespread and reliable utility. Despite evidence-based advantages, achieving robust BCR monitorability remains challenging due to highly variable stimulation parameters. Standardized protocols can provide a pathway to enhance its potential by enabling widespread adaptability and ensuring consistent neuromonitoring outcomes. A systematic meta-analysis was performed across relevant databases, focusing on studies utilizing BCR as a multimodality IONM during spinal surgeries. The analysis primarily aimed to establish a feasible set of BCR stimulation parameters to enhance monitorability alongside an evaluation of the sensitivity and specificity of BCR in preventing genitourinary postoperative deficits. AI machine learning tools were also employed to determine stimulation parameter combinations associated with 100% monitorability, providing insights into optimal protocols. Optimal BCR monitorability (100%) was consistently achieved with stimulation intensity of 40–50 mA, pulse counts of 4–8, pulse durations between 0.1–0.5 ms, and interstimulus intervals (ISI) of 2–3 ms, reflecting the critical role of not only stimulation intensity but also the synergistically interdependent dynamics of involved parameters, including temporal dynamics. Broad intensity ranges paired with shorter pulse durations and higher pulse counts effectively enhanced neural activation, underscoring the craft of devising a precise set of stimulation parameters essential for achieving reliable monitorability. Machine learning analysis identified stimulation intensity and pulse count as the most influential predictors of monitorability, explaining 69.25% of the variance and providing key insights for optimizing stimulation protocols. BCR monitoring is pivotal in preserving sacral nerve integrity and minimizing postoperative deficits. Advancing parameter optimization within IONM protocols ensures improved monitorability, enhancing surgical precision and patient outcomes.

Literature Review of Subcortical Mapping Techniques in Glioblastoma Surgeries

2024-12-12T23:24:17+03:00

Subcortical mapping of glioblastoma is an intraoperative technique used during tumor resection to identify the motor and language pathways in the central nervous system of the brain that are possibly affected by glioblastoma, an aggressive type of brain tumor that develops from glial cells with poor prognosis. This technique involves using electrical probes in varying brain tissues in an awake patient to stimulate different brain regions and critical areas responsible for language and movement. Combining intraoperative modalities like somatosensory evoked potential (SSEP), direct electrical stimulation (DES), electromyography (EMG), and electrocorticography (ECoG), Electroencephalography (EEG), Train of four (TOF) and Phase reversal, the surgical team can monitor neural activity. Penfield and Taniguchi have developed two methods to map the corticospinal tracts intraoperatively. One of these approaches may be used depending on the tumor's location, the patient's medical history, the surgery, and other considerations. Like other intraoperative monitoring techniques, the use of subcortical mapping during tumor resection in glioblastoma helps surgeons minimize the risk of postoperative deficits with the possibility of improving surgical outcomes for patients with this disease.

Evaluating the Effectiveness of Intraoperative Neuromonitoring Modalities in Spinal Dysraphism Surgeries: A Systematic Review

2025-02-01T18:29:07+03:00

Introduction: Spinal dysraphism encompasses a group of neural tube defects that can lead to significant neurological impairment, necessitating surgical intervention. Intraoperative neurophysiological monitoring (IONM) is integral to preserving neurological function during these high-risk surgeries. This systematic review evaluates the effectiveness of various IONM modalities, including somatosensory evoked potentials (SSEPs), motor evoked potentials (MEPs), electromyography (EMG), and bulbocavernosus reflex (BCR), in reducing postoperative deficits.

Methods: A systematic review of the PubMed database from 1998 to 2024 was conducted per PRISMA guidelines. The keywords used in the research included “spinal dysraphism,” “IONM,” “neuromonitoring,” “spina bifida,” “pediatric,” “surgery,” and “neurosurgery.” Inclusion criteria specified that only English-language studies with at least 10 patients focused on IONM use in meningocele, myelomeningocele, and tethered spinal cord surgeries. Exclusion criteria ruled out reviews, case reports, conference abstracts, and animal studies. Neuromonitoring data were analyzed for efficacy in reducing postoperative neurological deficits compared to non-IONM surgeries.

Results: From 1,492 surgeries analyzed, 1,227 employed IONM, yielding a 7.25% postoperative neurological deficit rate compared to 15% in non-IONM procedures. Among the IONM group, multimodality monitoring consistently showed reduced risks of neurological complications. Variability in true positive and false negative rates among studies highlighted the need for standardized reporting and enhanced sensitivity across modalities.

Discussion: Multimodality IONM substantially reduces postoperative deficits, though its sensitivity and specificity require further refinement. Emerging techniques targeting sacral and autonomic pathways, such as pudendal nerve SSEPs and urinary bladder EMG and MEPs, offer promising advancements for comprehensive neural monitoring.

Conclusion: IONM significantly enhances surgical outcomes in spinal dysraphism by reducing postoperative neurological deficits. Standardized metrics, multimodal approaches, and innovation in monitoring techniques are essential to optimizing patient care. Future research should prioritize large-scale, controlled trials to validate these findings and enhance best practices.

Intraoperative Neurophysiological Monitoring (IONM) During Peripheral Nerve Hand Surgeries

2024-12-13T01:11:58+03:00

Intraoperative Neurophysiological Monitoring (IONM) plays a crucial role in peripheral nerve surgeries by providing real-time feedback on the functional integrity of nerves during surgical procedures. IONM helps identify the nerves and minimize the risk of nerve damage, a significant concern in hand surgeries due to the complex network of nerves involved. By continuously monitoring the electrical activity of nerves, surgeons can make informed decisions, thereby improving surgical outcomes and reducing postoperative complications. IONM techniques commonly used in these surgeries include electromyography (EMG), motor evoked potentials (MEPs), and somatosensory evoked potentials (SSEPs). These techniques allow for identifying and protecting critical nerve structures, particularly in delicate or high-risk procedures. Integrating IONM in peripheral nerve surgeries enhances the surgical intervention's precision and significantly improves patient safety and recovery.

The effect of dexmedetomidine on motor-evoked potentials during pediatric posterior spinal fusion surgery: a retrospective analysis.

2024-10-30T19:58:55+03:00

Intraoperative neurophysiological monitoring has rapidly become a de facto standard of care for pediatric posterior spine fusion surgeries, but debate still surrounds the optimal anesthetic regime to facilitate monitoring. Recent publications have questioned whether Dexmedetomidine is compatible with MEP monitoring. We report our real-world experience and conclude that in moderation, as a part of a balanced anesthetic protocol Dexmedetomidine is beneficial to the holistic care of the pediatric spine deformity patient.