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.

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 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.

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.