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.

Major liver resections,perioperative issues and posthepatectomy liver failure:A comprehensive update for the anesthesiologist

Significant advances in surgical techniques and relevant medium-and long-term outcomes over the past two decades have led to a substantial expansion in the indications for major liver resections.To support these outstanding results and to reduce perioperative complications,anesthesiologists must address and master key perioperative issues(preoperative assessment,proactive intraoperative anesthesia strategies,and implementation of the Enhanced Recovery After Surgery approach).Intensive care unit monitoring immediately following liver surgery remains a subject of active and often unresolved debate.Among postoperative complications,posthepatectomy liver failure(PHLF)occurs in different grades of severity(A-C)and frequency(9%-30%),and it is the main cause of 90-d postoperative mortality.PHLF,recently redefined with pragmatic clinical criteria and perioperative scores,can be predicted,prevented,or anticipated.This review highlights:(1)The systemic consequences of surgical manipulations anesthesiologistsmust respond to or prevent,to positively impact PHLF(a proactive approach);and(2)the maximal intensivetreatment of PHLF,including artificial options,mainly based,so far,on Acute Liver Failure treatment(s),to buytime waiting for the recovery of the native liver or,when appropriate and in very selected cases,toward livertransplant.Such a clinical context requires a strong commitment to surgeons,anesthesiologists,and intensivists towork together,for a fruitful collaboration in a mandatory clinical continuum.

Intra-operative hearing monitoring methods in middle ear surgeries

Hearing loss is a condition affecting millions of people worldwide. Conductive hearing loss (CHL) is mainly caused by middle ear diseases. The low frequency area is the pivotal part of speech frequencies and most frequently impaired in patients with CHL. Among various treatments of CHL, middle ear surgery is efficient to improve hearing. However, variable success rates and possible needs for prolonged revision surgery still frustrate both surgeons and patients. Nowadays, increasing numbers of researchers explore various methods to monitor the efficacy of ossicular reconstruction intraoperatively, including electrocochleography (ECochG), auditory brainstem response (ABR), auditory steady state response (ASSR), distortion product otoacoustic emissions (DPOAE), subjective whisper test, and optical coherence tomography (OCT). Here, we illustrate several methods used clinically by reviewing the literature.

Monitoring cerebral ischemia during cerebrovascular surgery

Patients undergoing intracranial cerebrovascular surgery under general anesthesia are at risk of cerebral ischemia due to the nature of the surgery and/or the underlying cerebrovascular occlusive disease.It is thus imperative to reliably and continuously monitor cerebral perfusion during this type of surgery to timely reverse ischemic processes.The aim of this review is to discuss the techniques currently available for monitoring cerebral ischemia during cerebrovascular surgery with a focus on the advantages and disadvantages of each technique.

INTRAOPERATIVE LOCALIZATION OF CORTICAL MOTOR EVOKED POTENTIALS IN CENTRAL SULCUS LESIONS

Objective To study direct cortical electrical stimulation technique for the recording of motor evoked potentials under general anesthesia in central sulcus lesions. Methods The largest N20-P25 response was recorded from postcentral gyrus by intraoperative monitoring of cortical motor evoked potentials in 10 patients with intracranial lesions near or in the central area. The muscles of upper extremity in all patients were activated by delivering stimulus to cortical areas continuously. Moving the cortical electrodes forward, the largest P20-N25 response, SEP phase reversal,was obtained as a motor center stimulus. In this site of cortex, a short train stimulation elicited reproducible muscle action potentials that could be observed from the oscilloscope without averaging.Results MEPs can be recorded, pre-and post-operatively, without motor deficits of upper limbs in all patients.Conclusion This technique seems to be preferable for intraoperative localization of motor evoked potentials in central sulcus lesions under total intravenous anesthesia.

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 APPLICATION OF CORTICAL SOMATOSENSORY EVOKED POTENTIAL MONITORING IN CHILD SCOLIOSIS SURGERY

Objective To study the application value of cortical somatosensory evoked potential (CSEP) monitoring in child scoliosis surgery. Methods In surgeries of fifty one children with scoliosis, the CSEP changes were continuously recorded by evoked potential instrument. The operations were performed under the guidance of CSEP monitoring. Results Before propping and reshaping, the latencies and amplitudes in all cases had no change. During propping and reshaping, the latencies of all cases were slowly elongated, but all less than 10 percent. The amplitudes in 15 cases dropped to 55 percent, but returned to 80 percent 3-8 minutes after stopping the operations or partially loosening the propped rods at once. The amplitude in one case suddenly dropped to 37 percent and returned to 54 percent half an hour after loosening the propped rods at once and recovered to the normal range one day after operation. All cases got ideal orthopedic results and no one had neurological complications post operation. Conclusion CSEP can accurately monitor the spinal injury and has a great value in preventing the spinal injury in child scoliosis surgery.

Protocol for electrophysiological monitoring of carotid endarterectomies

Near zero stroke rates can be achieved in carotid endarterectomy （CEA） surgery with selective shunting and electrophysiological neuromonitoring.though false negative rates as high as 40% have been reported.We sought to determine if improved training for interpretation of the monitoring signals can advance the efficacy of selective shunting with electrophysiological monitoring across multiple centers,and determine if other factors could contribute to the differences in reports.Processed and raw beta band （12.5-30 Hz） electroencephalogram （EEG） and median and tibial nerve somatosensory evoked potentials （SSEP） were monitored in 668 CEA cases at six surgical centers.A decrease in amplitude of 50% or more in any EEG or SSEP channel was the criteria for shunting or initiating a neuroprotective protocol.A reduction of 50% or greater in the beta band of the EEG or amplitude of the SSEP was observed in 150 cases.No patient showed signs of a cerebral infarct after surgery.Selective shunting based on EEG and SSEP monitoring can reduce CEA intraoperative stroke rate to a near zero level if trained personnel adopted standardized protocols.We also found that the rapid administration of a protective stroke protocol by attending anesthesiologists was an important aspect of this success rate.

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.

Intraoperative high-field magnetic resonance imaging, multimodal neuronavigation, and intraoperative electrophysiological monitoring-guided surgery for treating supratentorial cavernomas

Objective: To determine the beneficial effects of intraoperative high-field magnetic resonance imaging (MRI), multimodal neuronavigation, and intraoperative electrophysiological monitoring-guided surgery for treating supratentorial cavernomas. Methods: Twelve patients with 13 supratentorial cavernomas were prospectively enrolled and operated while using a 1.5 T intraoperative MRI, multimodal neuronavigation, and intraoperative electrophysiological monitoring. All cavernomas were deeply located in subcortical areas or involved critical areas. Intraoperative high-field MRIs were obtained for the intraoperative“visu-alization”of surrounding eloquent structures,“brain shift”corrections, and navigational plan updates. Results: All cavernomas were successfully resected with guidance from intraoperative MRI, multimodal neuronavigation, and intraoperative electrophysiological monitoring. In 5 cases with supratentorial cavernomas, intraoperative “brain shift” severely deterred locating of the lesions;however, intraoperative MRI facilitated precise locating of these lesions. During long-term (>3 months) follow-up, some or all presenting signs and symptoms improved or resolved in 4 cases, but were unchanged in 7 patients. Conclusions: Intraoperative high-field MRI, multimodal neuronavigation, and intraoperative electrophysiological monitoring are helpful in surgeries for the treatment of small deeply seated subcortical cavernomas.

Effect of insulin on hyperkalemia during anhepatic stage of liver transplantation

AIM:To investigate the effectiveness of insulin on decreasing serum potassium concentration during anhepatic stage of orthotopic liver transplantation. METHODS:Sixteen patients with serum potassium concentrations greater than 4.0 mmol/L at the onset of anhepatic stage were randomized into two groups.The patients in control group (n=8) received no treatment, while those in treatment group (n=8) received an intravenous bolus injection of regular insulin (20U) 10 min into the anhepatic stage,followed by a glucose infusion (500mL 50g/L dextrose) over 15 min. RESULTS:In control group,potassium concentration underwent no changes whereas in treatment group,it decreased from 4.8±0.48 mmol/L to 4.19±0.55 mmol/L (mean±SD) within 15 min and to 3.62±0.45 mmol/L 60 min after the therapy.The potassium concentration was lower in treatment group than in control group within 30 min of treatment (3.94±0.57 vs 4.47±0.42 mmol/L, respectively;P<0.05),and increased similarly 30 s after graft reperfusion in both groups of patients,but remained lower in treatment group (5.81±2.78 vs 7.44±1.75 mmol/L, respectively;P<0.05).The potassium concentration returned to pre-reperfusion levels within 5 min after graft reperfusion. CONCLUSION:In patients undergoing orthotopic liver transplantation,the administration of insulin rapidly decreases serum potassium concentration even in the absence of the liver,suggesting an important contribution by extrahepatic tissues in insulin-stimulated uptake of potassium.

Analysis of the successful clinical treatment of 140 patients with parathyroid adenoma:A retrospective study

BACKGROUND Parathyroid adenoma(PA) sometimes recurs after surgery,how to improve the surgical success rate of PA is the key to the treatment of this disease.AIM To investigate the clinical features,diagnosis,and surgical treatment of patients with PA.METHODS Patients who were pathologically confirmed with PA and had undergone surgery for the first time between January 2010 and December 2017 at the Beijing Shijitan Hospital affiliated to Capital Medical University were included in the study.The clinical features,localization diagnosis,and surgical treatment of these patients were analyzed.RESULTS Of the 140 patients,32 were male and 108 were female;132 cases had one adenoma,and 8 had two adenomas.In addition,114 cases had clinical symptoms,among which 51,28,23,8,and 4 had urinary system,skeletal system,digestive system,neuromuscular system,and neuropsychiatric symptoms,respectively,while 26 cases had no obvious symptoms.The median level of preoperative parathyroid hormone(PTH) was 201.0 pg/m L.The positive detection rate of technetium-99m sestamibi(Tc-99m MIBI) single-photon emission computed tomography/computed tomography(SPECT/CT),ultrasound examination,and the combined use of Tc-99m MIBI SPECT/CT and ultrasound examination was 92.9%,85.5%,and 96.4%,respectively.Open surgery was performed in all patients,and PTH was monitored during surgery.The success rate of surgery was 98.6%.After surgery,21 cases developed hypocalcemia,1 case developed temporary hoarseness,and 19 cases had transient hypoparathyroidism but there was no permanent hypoparathyroidism,postoperative hemorrhage,or hematoma in the surgical area.CONCLUSION For patients with clinically unexplained skeletal system,urinary system,and neuropsychiatric symptoms,the possibility of PA should be considered.Imaging examinations such as ultrasound and Tc-99m MIBI SPECT/CT could be integrated before surgery to obtain accurate localization diagnosis.Precise preoperative localization,intraoperative PTH monitoring,and delicate surgery to protect the integrity of the PA capsule ensure a minimally invasive and successful surgery.

Tailored keyhole surgery for basal ganglia cavernous malformation with preoperative three-dimensional pyramidal tracts assessment and intraoperative electrophysiological monitoring

Background:Accurately mapping the pyramidal tracts preoperatively and intraoperatively is the primary concern when operating on cavernous malformations (CMS) in the basal ganglia.We have conducted new methods for preoperative planning and have tailored lesion resection to prevent the damage of pyramidal tracts.Patients and methods:Eleven patients harboring cavernous malformations in basal ganglia were treated surgically from April 2008 to January 2015.Surgical planning was based on three-dimensional diffusion tensor pyramidal tractography and Virtual Reality system.Intraoperative detecting of pyramidal tracts with subcortical stimulation mapping and motor evoked potential monitoring were performed.The extent of resection and postoperative neurological function were assessed in each case.Results:Total removal of the cavernous malformations were achieved in each case.Four of the total eleven cases presented temporary neurological deficits,including one occurrence of hemiparesis and three occurrences of hemianesthesia.No permanent neurological deficit was developed in this series of cases.Conclusion:Three-dimensional diffusion tensor pyramidal tractography is quite helpful for preoperative planning of basal ganglia cavernous malformations,especially in choosing a suitable surgical approach.Intraoperative detection of pyramidal tracts with subcortical stimulation mapping and motor evoked potential monitoring play important roles in preventing damage to pyramidal tracts during lesion resection.

Intraoperative monitoring of the recurrent laryngeal nerve in surgeries for thyroid cancer: a review

Intraoperative nerve monitoring(IONM)has evolved into an objective tool not only for the identification but also for the preservation and prognostication of function of the recurrent laryngeal nerve in thyroid surgeries.Technical improvements have resulted in the increasing incorporation of IONM into operating rooms around the world.The importance of adherence to recommended standards is also recognized as being vital in optimizing the efficacy of IONM.The advent of continuous IONM has made real-time nerve monitoring possible,thus providing the surgeon with an ally in difficult surgeries.Additionally,as thyroid surgeries are evolving into remote access and minimally invasive procedures,so also is the applicability of IONM.This review focuses on the use of IONM for nerve monitoring in thyroidectomies for neoplastic conditions while discussing the rationale,technique,and interpretation of findings and their implications.

Facial nerve monitoring in parotid gland surgery:Design and feasibility assessment of a potential standardized technique

Background:Even though the use of nerve monitoring during parotid gland surgery is not the gold standard to prevent damage to the nerve,it surely offers some advantages over the traditional approach.Different from thyroid surgery,where a series of steps in intraoperative nerve monitoring have been described to confirm not only the integrity but—most importantly—the function of the recurrent laryngeal nerve,in parotid gland surgery,a formal guideline to follow while dissecting the facial nerve has yet to be described.Methods:A five‐year retrospective study was done reviewing the intraoperative records of patients who underwent parotid gland surgery under neural monitoring.The operative findings regarding the neuromonitoring process,particularly in regard to the amplitude of two main branches,were revised.A literature search was done to search for guidelines to follow when a facial nerve loss of signal is encountered.Results:Fifty‐five patients were operated on using the Nim 3 Nerve Monitoring System(Medtronic);31 were female patients,and 47 patients had benign lesions.Minimum changes were observed in the amplitude records after a comparison was made between the first and the last stimulation.There were only three articles discussing the term loss of signal during parotid gland surgery.Conclusion:Today,no sufficient attention has been given to the facial nerve monitoring process during parotidectomy.This study proposes a formal guideline to follow during this procedure as well as an instruction to consider when a loss of signal is observed to develop a uniform technique of facial nerve stimulation.

Value of somatosensory evoked potentials in diagnosis, surgical monitoring and prognosis of cervical spondylotic myelopathy

Background The value of somatosensory evoked potentials （SEPs） in the diagnosis and prognosis of cervical spondylotic myelopathy, as well as the usefulness of monitoring intraoperative potentials in terms of safety and predictive factors were investigated. Methods Each of the 76 myelopathic patients underwent surgical intervention. According to the wave configurations of the SEPs, the cases were categorised into four groups： Type Ⅰ, Ⅱ, Ⅲ and Ⅳ. The clinical myelopathy disability was classified and the severity of neurological deficits was scored. Clinical function after surgery was evaluated. Preoperative potentials and intraoperative monitoring were categorized. The correlations between .evoked potentials detection, monitoring, myelopathy disability and surgical outcome in the different groups were discussed. Results According to the configurations of the SEPs, there were 27 patients （36%） of Type Ⅰ, 30 patients （39%） of Type Ⅱ, 8 patients （11%） of Type Ⅲ, and 11 patients （14%） of Type Ⅳ. The categorised evoked potentials were shown to be significantly associated with the clinical representation of myelopathy （P 〈0.01） and the recovery rate from identifiable SEPs waves （groups A, B and C） was significantly higher than unidentifiable waves （group D, P〈0.01）. A deterioration of SEPs was detected in 23 cases （30%）, whereas there was no change in 40 cases （53%） and improvements in 13 cases （17%）. A significant difference in recovery rates could be observed in various monitoring groups within the short-term follow-up period, while there were no obvious differences in the long-term follow-up groups. Conclusions SEP technique is a valuable and practical tool for the diagnosis, monitoring and prognosis of myelopathy. Classified evoked potentials are well correlated with cervical spondylotic myelopathy disability, and unidentifiable SEPs waves in patients are indicative of a relatively poor outcome. In addition, intraoperative monitoring of SEPs plays an important role in protecting neural structures during cervical spine surgery.

喉返神经术中监测的原理与应用

喉返神经损伤是甲状腺手术最严重的并发症,导致患者生活质量下降甚至危及生命。如何规避喉返神经损伤是外科医师一直探索的课题。甲状腺手术中常规识别喉返神经是喉返神经保护的＂金标准＂。但即使外科操作标准化，

甲状腺手术中喉返神经监测技术的优化与解读

喉返神经损伤是甲状腺手术常见并发症,严重影响患者生活质量,是困扰外科医师的技术问题。术中神经监测不仅可以定位和鉴别喉返神经、查找损伤点、发现导致损伤的步骤、预测术后声带功能,而且可以阐明喉返神经损伤的机制。

术中神经监护在耳鼻咽喉头颈外科应用

1面神经术中监护面神经是人体中穿过骨管最长的脑神经,由脑干发出经内耳道进入颞骨,经茎乳孔出颞骨。分支支配除上睑提肌外所有的面部表情肌和二腹肌后腹、耳后肌等肌肉。由于面神经行程曲折、复杂,周围结构重要,在手术中因为解剖变异、病变包裹压迫及术者技术经验的原因都有可能导致面神经损伤引起面瘫，由于面瘫直接伤及患者面容和交流，