Pre-operative electrodiagnostic studies and intraoperative neurophysiologic monitoring:power and pitfalls

Outpatient electrodiagnostic studies and intraoperative monitoring are essential tools for the surgical management of nerve injury.Decisions are based on the diagnostic certainty afforded by outpatient electrodiagnostic studies,which are more sensitive and specific than clinical examinations regarding the nature and localization of a nerve lesion.Intraoperative neurophysiologic monitoring detects changes in neurologic function during surgery.It provides significantly better information than visual inspection of the operative field,minimizing postoperative neurologic deficits due to surgical manipulation(e.g.,stretching,compression,heating from electrocauterization,constriction,or clamping of local blood vessels).These techniques exploit similar neurophysiologic principles to afford enhanced diagnostic and real-time functional data during surgery.However,an understanding of their limitations is critical for the interpretation of these data.This review discusses these techniques,including their use,advantages,and disadvantages in diagnosing and managing three essential nerve lesions amenable to surgical management-radiculopathy,mononeuropathy,and brachial plexopathy.

The role of intraoperative neurophysiological monitoring in intramedullary spinal cord tumor surgery

Intramedullary tumors are a class of central nervous system tumors with an incidence of 2 to 4%.As they are located very deep and frequently cause postoperative neurological complications,surgical resection is difficult.In recent years,many surgeons have performed electrophysiological monitoring to effectively reduce the occurrence of post-operative neurological complications.Modern electrophysiological monitoring technology has advanced considerably,leading to the development of many monitoring methods,such as SSEPs,MEPs,DCM,and EMG,to monitor intramedullary tumors.However,electrophysiological monitoring in tumor resection is still being studied.In this article,we discussed the different monitoring methods and their role in monitoring intramedullary tumors by reviewing previous studies.Intratumorally tumors need to be monitored for a summary of the condition of the patient.Only by using various monitoring methods flexibly and through clear communication between surgeons and neurophysiological experts can good decisions be made during surgery and positive surgical results be achieved.

Possible Cortical Spreading Depression Recorded Intraoperatively Following a Generalized Seizure: Illustrative Case

Background: We present a compelling case fitting the phenomenon of cortical spreading depression detected by intraoperative neurophysiological monitoring (IONM) following an intraoperative seizure during a craniotomy for revascularization. Cortical spreading depression (CSD, also called cortical spreading depolarization) is a pathophysiological phenomenon whereby a wave of depolarization is thought to propagate across the cerebral cortex, creating a brief period of relative neuronal inactivity. The relationship between CSD and seizures is unclear, although some literature has made a correlation between seizures and a cortical environment conducive to CSD. Methods: Intraoperative somatosensory evoked potentials (SSEPs) and electroencephalography (EEG) were monitored continuously during the craniotomy procedure utilizing standard montages. Electrophysiological data from pre-ictal, ictal, and post-ictal periods were recorded. Results: During the procedure, intraoperative EEG captured a generalized seizure followed by a stepwise decrease in somatosensory evoked potential cortical amplitudes, compelling for the phenomenon of CSD. The subsequent partial recovery of neuronal function was also captured electrophysiologically. Discussion: While CSD is considered controversial in some aspects, intraoperative neurophysiological monitoring allowed for the unique analysis of a case demonstrating a CSD-like phenomenon. To our knowledge, this is the first published example of this phenomenon in which intraoperative neurophysiological monitoring captured a seizure, along with a stepwise subsequent reduction in SSEP cortical amplitudes not explained by other variables.

The application of intraoperative neurophysiological monitoring in selective dorsal neurotomy for primary premature ejaculation:a prospective single-center study

Selective dorsal neurotomy(SDN)is a surgical treatment for primary premature ejaculation(PE),but there is still no standard surgical procedure for selecting the branches of the dorsal penile nerves to be removed.We performed this study to explore the value of intraoperative neurophysiological monitoring(IONM)of the penile sensory-evoked potential(PSEP)for standard surgical procedures in SDN.One hundred and twenty primary PE patients undergoing SDN were selected as the PE group and 120 non-PE patients were selected as the normal group.The PSEP was monitored and compared between the two groups under both natural and general anesthesia(GA)states.In addition,patients in the PE group were randomly divided into the IONM group and the non-IONM group.During SDN surgery,PSEP parameters of the IONM group were recorded and analyzed.The differences in PE-related outcome measurements between the perioperative period and 3 months'postoperation were compared for the PE patients,and the differences in effectiveness and complications between the IONM group and the non-IONM group were compared.The results showed that the average latency of the PSEP in the PE group was shorter than that in the normal group under both natural and GA states(P<0.001).Three months after surgery,the significant effective rates in the IONM and non-IONM groups were 63.6%and 34.0%,respectively(P<0.01),and the difference in complications between the two groups was significant(P<0.05).IONM might be useful in improving the short-term therapeutic effectiveness and reducing the complications of SDN.

Anesthetic considerations for patients with acute cervical spinal cord injury

Anesthesiologists work to prevent or minimize secondary injury of the nervous system and improve the outcome of medical procedures.To this end,anesthesiologists must have a thorough understanding of pathophysiology and optimize their skills and equipment to make an anesthesia plan.Anesthesiologists should conduct careful physical examinations of patients and consider neuroprotection at preoperative interviews,consider cervical spinal cord movement and compression during airway management,and suggest awake fiberoptic bronchoscope intubation for stable patients and direct laryngoscopy with manual in-line immobilization in emergency situations.During induction,anesthesiologists should avoid hypotension and depolarizing muscle relaxants.Mean artery pressure should be maintained within 85–90 mmHg（1 mmHg = 0.133 kPa; vasoactive drug selection and fluid management）.Normal arterial carbon dioxide pressure and normal blood glucose levels should be maintained.Intraoperative neurophysiological monitoring is a useful option.Anesthesiologists should be attentive to postoperative respiratory insufficiency（carefully considering postoperative extubation）,thrombus,and infection.In conclusion,anesthesiologists should carefully plan the treatment of patients with acute cervical spinal cord injuries to protect the nervous system and improve patient outcome.

脊柱矫形术中神经监测研究进展

脊柱侧凸矫形手术是治疗脊柱侧凸畸形最常用的治疗方式之一,而术后神经功能缺损是脊柱侧凸手术术后最严重的并发症。针对这种难以承受的风险,自上世纪以来,临床上陆续出现了很多监测检查神经功能完整性的方法,如术中唤醒试验、肌电图、体感诱发电位、运动诱发电位等。近年来,术中多模式结合的神经监测方案被逐渐推广和使用,其特异性及准确率较单一神经监测方式有再一次提升。本文通过对多种术中神经电生理监测技术原理、优劣势、影响因素、准确性等进行多方面介绍,旨在指导临床医师在不同病例中选择最佳监测手段。

Stretching boundaries in neurophysiological monitoring

The most prevalent among nervous system tumors significantly jeopardize patient health.For nerve integrity preservation after tumor removal,continuous intraoperative neurophysiological monitoring(CINM)is indispensable during microsurgery.The paper highlights the articles about the development of a system that employs soft and stretchable organic electronic materials for CINM.This innovative system harnesses soft and stretchable organic electronic materials and deploys conductive polymer electrodes with low impedance and modulus.These electrodes facilitate uninterrupted near-field action potential recording during surgery,resulting in enhanced signal-to-noise ratios and reduced invasiveness.Additionally,the system's multiplexing capabilities enable precise nerve localization,even in the absence of anatomical landmarks.

Resection of intramedullary spinal cord tumor under awake anesthesia: A novel approach to minimize postoperative motor deficits

Objective: To observe advantages and disadvantages of the resection of intramedullary spinal cord tumor under awake anesthesia. Methods: Two patients with intramedullary spinal cord tumor underwent resection under awake anesthesia and followed up post-operatibely for any motor deficits. Results: Patients who underwent tumor resection under awake(AAA) anesthesia combined with intraoperative NPM had no motor deficits postoperatively. More accurate and nondelayed responses were observed in the awake cycle of anesthesia and helped guide surgery, thus avoiding injuries to the spinal cord. Conclusion: Intramedullary spinal cord tumors are not common, but only gross total resection(GTR) can provide complete remission of symptoms and progression-free survival. However, GTR sometimes results in motor function deficits postoperatively,particularly when the cervical cord is involved, and especially if surgery is done under general anesthesia with intraoperative neurophysiological monitoring(NPM) alone,because of delayed sensory evoked potential and motor evoked potential responses. We present two cases that underwent GTR of cervical intramedullary spinal cord tumors under an asleep-awake-asleep(AAA) cycle of anesthesia, combined with intraoperative NPM in which no post-operative motor deficits were observed on 6-months follow up.