Koht, Sloan, Toleikis's Monitoring the Nervous System for Anesthesiologists and Other Health Care Professionals

Preface
Acknowledgments
Contents
Contributors
Part I: Monitoring Techniques
1: Somatosensory-Evoked Potentials
Introduction
Anatomy and Vascular Supply
Methods
Stimulation
Recording
Intraoperative Variables Affecting SSEPS: Pharmacology and Physiology
Inhalational Anesthetics
Intravenous Anesthetics
Temperature
Tissue Perfusion
Oxygenation/Ventilation
Intracranial Pressure
Other Physiologic Variables
Criteria for Intervention During Intraoperative SSEP Monitoring
Dorsal Column Mapping
Other Intraoperative Applications for SSEPs
References
2: Transcranial Motor-Evoked Potentials
Introduction
Anatomy of the MEP Response
Technical Aspects of MEP Monitoring
Optimizing Compound Muscle Action Potential
Patient Characteristics Contributing to Outcomes
Effect of Anesthesia Management
Outcomes
Conclusion
References
3: Auditory-Evoked Potentials
Anatomy of the Auditory System
Conduction of Auditory Signals from Ear to Cochlea
Neural Components of the Auditory System and Electrical Generators Along the Auditory Pathway
Cochlea: Electrocochleogram
Auditory Pathway from Cochlear Nerve to Midbrain
Auditory Brainstem-Evoked Responses and Cochlear Nerve Compound Action Potential
Primary Auditory Cortex: Mid-Latency Auditory-Evoked Potentials
Vascular Supply of Auditory Pathway Structures
Techniques for Recording Auditory-Evoked Potentials
Stimulation
Electrocochleogram
Compound Nerve Action Potentials from the Cochlear Nerve
Brainstem Auditory-Evoked Potentials
MLAEPs
Anesthetic and Physiologic Considerations for Monitoring of Auditory Brainstem Responses
ABR Alarm Criteria
References
4: Visual-Evoked Potentials
Introduction
Flash Electroretinogram (F-ERG)
Flash Visual-Evoked Potentials (F-VEPs)
Introduction of the Intraoperative Monitoring of the Visual System: Orbital Surgeries
Identified Sources of Intraoperative Variations in F-VEPs
Recognition of a Reliable Monitoring of Vision
Anatomy and Physiology of the Visual System
Realization of Intraoperative Electroretinogram (ERG) and Flash Visual-Evoked Potentials (F-VEPs)
Intraoperative ERG
Intraoperative F-VEP
Devices for Flash Stimulation
Characteristics of Stimulation Light
ERG Recordings and Analyses
F-VEP Recordings and Analyses
Warning Criteria
Warning Criteria for ERGs
Warning Criteria for F-VEPs
Other Intraoperative Applications with ERG and F-VEP: Cardiovascular Surgeries, Deep Brain Stimulation
Direct Electrical Stimulation of Visual Pathway
Effects of Temperature
Effects of Anesthesia on ERGs
Effects of Anesthesia on F-VEPs
Conclusion
References
5: Deep Brain Stimulation
Introduction
Surgery
Microelectrode Recording (MER)
Complications
Asleep vs. Awake Surgery
The MER Procedure
Target Structures for the Case Examples
Cases and Disorders
Case 1: Routine DBS of the STN in Parkinson’s Disease
Clinical Symptoms of PD
Parkinson’s Disease
Procedure and Decisions
Case 2: Noncomplex (PD-STN, Asleep)
Preoperative Evaluation
Procedure and Decisions
Case 3: Complex
Dystonia
Procedure and Decisions
Case 4: Complex
Status Dystonicus
Procedure and Decisions
Conclusion
References
6: Intraoperative Electromyography
General Principles of EMG
Anatomy of the Lower Motor Neuron System
Motor Unit
Neuromuscular Junction
Anesthesia Considerations for EMG
Neuromuscular Blocking Agents
Local Anesthetic Agents
Anesthesia for Other Myogenic Modalities
Train-of-Four Technique
Common Troubleshooting Issues in Train-of-Four
Clipping
Misinterpretation of Train-of-Four Data and Stimulus Artifact
Spontaneous EMG—Fundamental Principles
Neuronal Axons Respond to Mechanical Stimuli
Neuronal Axons Respond to Thermal Stimuli
Recording Electrode Considerations
Electrode Type
Location and Spacing
Electrode Configuration
EMG Recording Parameters
Recording Sweep (Time Base)
Filters
Sensitivity
Use of Audio Feedback
Audio Feedback
Audio Squelch or Muting
Patterns of Iatrogenic EMG Activity
Differential Diagnosis for EMG Activity
“Light” Anesthesia
Patient Positioning
Thermal Induced EMG from Irrigation
Artifact and Electrical Noise
Triggered EMG—Fundamental Principles
Stimulus Configurations: Monopolar Versus Bipolar
Stimulus Artifact in Triggered EMG
EMG Application and Technique for Cranial Nerves
Electrode Placement for Cranial Nerves
Cranial Nerves III, IV, and VI
Cranial Nerves V and VII
Cranial Nerves IX, X, XI, and XII
Glossopharyngeal Nerve—CNIX
Vagus Nerve—CNX
Spinal Accessory Nerve—CNXI
Hypoglossal Nerve—CN XII
Stimulus and Recording Parameters and Technique for Triggered Cranial Nerve EMG
Stimulus Intensity for Cranial Nerves
Intracranial Cranial Nerve Stimulation
Extracranial Cranial Nerve Stimulation
Stimulating Dissectors
Safety Issues with Cranial Nerve Stimulation
Cranial Nerve Identification with Triggered EMG
Using Triggered EMG to Evaluate Facial Nerve Function After Acoustic Neuroma Surgery
Mapping the Floor of the Fourth Ventricle
Mapping Technique
Triggered EMG Application in Thyroid Surgery
Factors Causing Amplitude and/or Latency Changes in Vagus Nerve CMAP
EMG Applications and Technique in Spinal Procedures
Recommended Recording and Stimulating Parameters for Spinal EMG
Electrode and Montage Considerations for Spinal EMG
EMG Electrode Placements According to Vertebral Levels Involved in the Surgery
Assessing Nerve Root Function and Pedicle Screw Placement
Description of Pedicle Screw Stimulation Technique
Stimulus Setup
Stimulation
Automated Thresholding
Sources of False-Negative Screw Thresholds
Summary of Factors that May Falsely Increase Thresholds
Sources of False Positive Screw Thresholds
Minimally Invasive Lateral Transpsoas Approach to the Spine
Technique for Triggered EMG during the Lateral Transpsoas Approach
Cauda Equina Surgery
Selective Dorsal Rhizotomy
Suprasegmentally Generated EMG Discharges (SEDs)
References
7: The Use of Spinal Reflex Responses for IOM
Introduction
Anatomy and Neurophysiology
Spinal Cord Pathophysiology
Spinal Nerve Root Pathophysiology
Late Responses
F-Responses
F-Response Facilitation—Interaction Technique
A-Waves
H-Reflexes: Monosynaptic, Oligosynaptic
Neurophysiologic Basis of H-Reflexes
Gastrocnemius H-Reflex
Gastrocnemius H-Reflex Normal Parameters
Gastrocnemius H-Reflex Stimulation and Recording Techniques
Flexor Carpi Radialis H-Reflex
Flexor Carpi Radialis H-Reflex Background and Normal Parameters
Flexor Carpi Radialis H-Reflex Stimulation and Recording Techniques
Anesthetic Effects on Spinal Cord CPGs
Clinical Correlation of H-Reflexes and F-Responses
Clinical Correlation Summary
H-Reflex Facilitation—Interaction Techniques
Polysynaptic Reflexes
Sacral Reflex
Intraoperative Application of BCRs
Monosynaptic and Polysynaptic Reflexes: Selective Dorsal and Ventral Root Rhizotomy
Background
Technical Summary
Lower Extremity Intralimb and Interlimb Polysynaptic Reflexes
Conclusion
References
8: Brainstem Reflexes Under General Anesthesia
Introduction
Effects of General Anesthesia on Brainstem Centers
Anatomy and Physiology of Specific Brainstem Reflexes Under General Anesthesia
Blink Reflex
H-Masseter
Laryngeal Adductor Reflex (LAR)
Methodologies for Eliciting Brainstem Reflexes Under General Anesthesia
Blink Reflex
H-Masseter
Laryngeal Adductor Reflex (LAR)
Contribution of Anesthesiology to Successfully Monitor Brainstem Reflexes
Correlation of Brainstem Reflexes Monitoring with Postoperative Outcome
Conclusion
References
9: Brain Mapping: Asleep and Awake
Introduction
Planning
Presurgical Mapping
Planning of the Intraoperative Mapping Procedure
Language and Parietal Mapping and Monitoring During Awake Craniotomies
Establishing Baselines
The Mapping Strategy
Continuous Monitoring of Language or Parietal Functions
Subcortical Mapping
Ictal Events
Location of the Central Sulcus by Median SSEP Phase Reversal Technique
Motor Mapping via Electrical Stimulation with the Penfield Paradigm
Motor Mapping and Monitoring via Electrical Stimulation with the Multipulse Train Paradigm
Subcortical Motor Mapping
Protection of the Thalamocortical Input to the Peri-Rolandic Region
Electrocorticography (ECoG) in Functional Mapping
Conclusions
References
10: Intraoperative Monitoring of EEG and Processed EEG
Introduction
The Genesis of the EEG
Cytoarchitecture
Control of Rhythm and Anesthesia-Induced Sedation and Loss of Consciousness
EEG Signal
Time-Domain Method
Frequency-Domain Methods
Raw and Processed EEG
Anesthetic Drugs Impact on EEG
Propofol and Barbiturates
Benzodiazepines
Ketamine
Dexmedetomidine
Opioids
Volatile Agents
Nitrous Oxide
Muscle Relaxants
Clinical Utility of Raw and Processed EEG
Future Directions of EEG Monitoring
Conclusion
References
11: Central Nervous System Near-Infrared Spectroscopic Monitoring: Technique and Clinical Application
Introduction
Instrumentation
Transcranial NIRS Technology
Regional Cerebral Oxygen Saturation Measurement
Safety Considerations
Limitations of Cerebral Oximetry
Environmental Factors
Patient Factors
Technical Limitations
Rationale for Cerebral NIRS Monitoring
Physiology Factors Affecting NIRS Monitoring
Basics of Oxygen Demand and Delivery
Patient Factors
Systemic Arterial Pressure
Systemic Oxygen Delivery
Systemic Arterial PaCO2 and pH
Cerebral Blood Inflow and Outflow Obstruction
Cerebral Oxygen Consumption
Supplemental Cerebral Perfusion
Differential Diagnosis of Cerebral Oxygen Desaturation and Treatment Algorithm
Clinical Uses for Cerebral Oximetry
Applications in Neonatology
rScO2 Measurement in Neonates with HIE
Measurement of Cerebral Autoregulation in Infants with HIE
Measurement of Mitochondrial Redox State
Measurement of CBF
Measurement of CMRO2
Hybrid and Emerging Technologies in Neonatology
Applications in Vascular Surgery
Applications in Cardiac Surgery
Overview of rScO2 Monitoring in Cardiac Surgery
Effects of CPB on rScO2
rScO2, Neurologic Outcomes, and Organ System Dysfunction After Cardiac Surgery
rScO2 as a Monitor of Cardiac Output and Hematocrit After Cardiac Surgery
Conclusions on Cerebral Oximetry Monitoring in Cardiac Surgery
Applications in Neurologic Critical Care
Overview of the Role of Cerebral Oximetry in Neurologic Critical Care
Adequacy of Cerebral Oxygenation
Cerebral Autoregulation
Cerebral Blood Flow
Seizures
Intracranial Bleeding
Intracranial Pressure
Future Directions for NIRS Research
Conclusions
References
12: Intracranial Pressure Monitoring
Introduction
The ICP Waveforms and Pressure Reactivity Index
Indications of ICP Monitoring
ICP Monitoring Techniques
Intraparenchymal ICP Monitor/Micro Transducer
Subarachnoid ICP Monitor
Epidural Monitor
Intraventricular Monitor
Noninvasive ICP Monitoring
Optic Nerve Sheath Diameter (ONSD)
Transcranial Doppler (TCD)
Other Methods of ICP Monitoring
ICP-Guided Therapy
Summary
References
13: Monitoring Cerebral Blood Flow
Physiology
Mechanisms of CBF Regulation
Autoregulation and Altered Humoral Responses
Cerebrovascular Reserve
CBF Measurement and Clinical Applications of Specific Techniques Perioperatively
Stable Xenon CTCBF (XeCTCBF)
Xe133 CBF
Jugular Bulb AVO2 Difference
Thermodilution rCBF
Transcranial Doppler
Vasospasm
Cerebrovascular Reserve
Intracranial Pressure
Brain Death
Vessel Patency
Emboli
Hyperemia
Noninvasive, Spectroscopy-Based Monitors of CBF
Imaging-Based Modalities
Blood Oxygenation Level-Dependent (BOLD) MRI
Arterial Spin Labeling (ASL)
Computed Tomography Perfusion
Intraoperative Cerebral Blood Flow Monitoring
Indocyanine Green (ICG) Videoangiography
Laser Speckle Contrast Imaging
Monitors of Autoregulation
TCD-Based autoregulation (Mx)
Pressure-Reactivity Index (PRx)
Cerebral Oximetry Index (COx)
Summary
References
14: Transcranial Doppler Ultrasonography
Introduction
Technology
Practical Cerebrovascular Anatomy
Examination Technique
Interpreting TCD Ultrasonography
Interpretation of CBFV
Cerebrovascular Reactivity to Carbon Dioxide (Vasomotor Reactivity)
Cerebral Autoregulation Testing
Microemboli Monitoring
Noninvasive Estimation of Intracranial Pressure (ICP)
Clinical Applications of TCD Ultrasonography
Diagnosing and Monitoring of Cerebral Vasospasm
Monitoring During Carotid Artery Interventions
Assessment of Patterns and Extent of Collateral Circulation in Patients with Cerebrovascular Stenosis or Occlusion, Including Moyamoya Disease
Detection of Right-to-Left Shunts and Assessment for Patent Foramen Ovale (PFO)/Paradoxical Embolism
Detecting Microemboli Following Stroke or Transient Ischemic Attack
Monitoring Cerebral Thrombolysis in Acute Ischemic Stroke
Assessment of Stroke Risk in Children with Sickle Cell Disease
Monitoring Coronary Artery Bypass Surgery and Prosthetic Cardiac Valves [54]
TBI
Diagnosis of Cerebral Circulatory Arrest
Limitations
Conclusion
References
Part II: From Techniques to the Operating Room: General Considerations
15: IOM Instrumentation Layout and Electrical Interference
Introduction
Basic Electronics and Definitions
Definition 1
Definition 2
Definition 3
Definition 4
Definition 5
Pathway 1: The Skin of the Patient Cskin
Pathway 2: Ambient Sources of Electrical Noise Vnoise
The Basic IOM Recording Circuit
Tissue Physiologic Generator (Vtissue)
Circuit Component: Tissue Between Generator and Electrode (Ztissue)
Circuit Component: Electrode Connection to the Patient and Electrode Components (Zelectrode)
Circuit Component: The Wire Between the Electrode Patient End and Connector End (Zleadwire)
Circuit Component: Leadwire Connection to Safety Connector and Electrode to Amplifier Connection (Zpin)
Circuit Component: Amplifier Impedance (Za)
Circuit Component: Amplifier Iso-ground
Basic Circuit Summary Points
Understanding Sources of Electrical Interference
Practical Tips
Specifically for the Anesthesiologist
For the IOM Professional
During Patient Setup
When Troubleshooting Electrical Noise
Technical Note: Modern IOM Equipment and Grounding
Recording Pathway: Input Switching
Recording Pathway: Amplifiers
Recording Pathway: Anti-aliasing Filters
Recording Pathway: A/D Convertors
Recording Pathway: Digital Signal and Computer Processing
Conclusion
References
16: Signal Optimization in Intraoperative Neuromonitoring
Introduction
Patient-Related Issues
Somatosensory-Evoked Potentials
Peripheral Nerve Disorders
Central Nervous System Dysfunction
Motor-Evoked Potentials
Peripheral Nervous System Disorders
Central Nervous System Dysfunction
Electromyography and Nerve Conduction Studies
Electroencephalography
Anesthetic and Systemic Effects
Somatosensory-Evoked Potentials
Motor-Evoked Potentials
Electromyography
Electroencephalography
Technical Issues
Increased Electrical Noise
Electrical Noise: 60 Hz
Electrical Noise: High Frequency
Electrical Noise: Low Frequency or Intermittent
Electrical Noise: General Strategies
Poor Signal Amplitudes
Recording Technique
Stimulation Technique
Errors of Signal Acquisition
Electrode Plug-In Errors
System Errors
General Principles
Timing of Optimization
Prioritization
Conclusion
References
17: Optimization of Intraoperative Neurophysiological Monitoring Through Anesthetic Management
Introduction
Interaction Between IONM Modality and Anesthetic Technique
Impact of Patient-Related Factors on IONM
Mechanism of Drug Action
Anesthetic Effects on EEG
Effects on Neuronal Metabolism
Mechanisms of Consciousness and Unconsciousness
Natural Sleep Versus General Anesthesia
Anesthetic-Induced Unconsciousness
Propofol
Etomidate
Barbiturates
Ketamine
Dexmedetomidine
Benzodiazepines
Opioids
Halogenated Agents
Nitrous Oxide
EEG and Depth of Anesthesia Monitoring
EEG During Emergence from Anesthesia
Anesthesia Selection and EEG Monitoring
Anesthetic Effects on Evoked Potentials
Effect Based on Location of Synapses
Effect Based on Anesthesia Goals
Amnesia
Unconsciousness
Immobility
Antinociception
Effects of Specific Anesthetic Agents on Evoked Responses
Halogenated Inhalational Agents
Nitrous Oxide
Propofol
Etomidate
Benzodiazepines
Dexmedetomidine
Barbiturates
Opioids
Ketamine
Lidocaine, Magnesium, and Regional Anesthesia
NMBA
NMB and MEP
NMB and Facial Nerve Monitoring
NMB and Recurrent Laryngeal Nerve Monitoring
Peripheral Nerve Monitoring and Pedicle Screw Testing
Optimization of the Anesthetic Approach
Physiological Considerations in Anesthesia Management
Conclusion
References
18: Basic Evaluation and Effective Communication of IOM Signal Changes
Troubleshooting IOM Changes
Anesthetic IOM Changes
Physiologic IOM Changes
Positioning and IOM Changes
Technical IOM Changes
Communication Around IOM and IOM Changes
References
Part III: Clinical Applications
19: Anesthesia for Awake Neurosurgery
Introduction
Anesthesia for Awake Craniotomy
Patient Selection and Preparation
Intraoperative Period
Patient Positioning
Awake Brain Mapping and Monitoring
Electrocorticography (ECOG)
Intraoperative Adverse Events
Comparison of Techniques
Patient Experience
Benefits of Awake Craniotomy
Awake Placement of Electrodes for Deep Brain Stimulation
Awake Carotid Endarterectomy
Anesthesia for Awake MRI-Guided Intracranial Laser Interstitial Thermal Therapy
Awake Spine Surgery
Summary
References
20: Intraoperative Neurophysiologic Monitoring and Mapping of the Motor System During Surgery for Supratentorial Lesions Under General Anesthesia
Introduction
Case: Resection of an Insular Glioma
Risks of Surgery for Insular Tumors and Other Supratentorial Mass Lesions
Preservation of Nonmotor Function Using Mapping and Monitoring Techniques
Motor Mapping and Monitoring
Monitoring Results and Surgical Intervention
Possible Causes of the MEP Change and the Role of the Surgical Interventions
The Role of Subcortical Mapping to Identify the CST During Brain Tumor Removal
Why Is Neurophysiologic Monitoring Useful?
Conclusion
References
21: Intraoperative Neurophysiological Monitoring for Intracranial Aneurysm Surgery
Introduction
Case Presentation 1: MCA Aneurysm
Which Monitors Should You Consider for the Aneurysm Clipping?
What Do We Expect the Selected Neuromonitoring Modalities to Monitor During This Surgery?
What Are Some Drawbacks of Each of the Above Modalities in Relation to This Surgery?
What Is the Interpretation of These Neurophysiologic Monitoring Waveforms?
What Is the Cause of This Change?
What Is the Cause of These Changes?
Case Presentation 2: ICA/Ophthalmic Aneurysm
Should Only Upper Extremity SSEPs and TCMEPs, Only Lower Extremity SSEPs and TCMEPs, or Both Upper and Lower Extremity SSEPs and TCMEPs Be Monitored for This Surgery?
Case Presentation 3: Basilar Apex Aneurysm
How Does This Aneurysm Location Influence the Choice of Neurophysiologic Monitoring Modalities to Be Used?
What Are the Most Likely Etiologies for This Signal Change?
References
22: Intracranial Arteriovenous Malformation Surgery
Introduction
Case Presentation
What Management Could Be Considered to Potentially Decrease Blood Loss Prior to Surgical Resection of the AVM?
Which Monitors Should You Consider for the Surgical Resection?
What Are Potential Benefits of Combining SSEP and MEP Monitoring?
Although the Majority of AVMS Are Suptratentorial in Location, What Additional Neuromonitoring Would Be Helpful If the AVM Involved the Posterior Fossa/Vertebrobasilar Circulation?
When Should Neuromonitoring Be Performed During the Case?
Transcranial MEP Stimulation Can Cause Movement of the Patient. What Can Be Done to Minimize This Movement?
After Initial Baseline MEP Recordings Are Obtained, You Note Detectable Signals From Bilateral Upper and Lower Extremities. However, You Notice That Both Contralateral and Ipsilateral Waveforms Are Obtained With Stimulation of One Hemisphere. What Is
The Stimulation Intensity Is Decreased to the Point Where Only Contralateral Extremity Waveforms Are Obtained. However, Now There Is No Signal From One Foot. Surgery Has Not Yet Begun. What Can Be Done to Improve the Signal Knowing That Increasing the
What Nonradiographic Intraoperative Method Could Be Used to Help Delineate the Vasculature While the Surgeons Are Dissecting Around the AVM?
The Electrophysiologist Reports to the Surgery and Anesthesia Teams That the Amplitude of the MEP Response From One Lower Extremity Has Decreased Significantly. The Surgeons State That They Are Not Working in the Territory of the Anterior Cerebral Art
What Affects the Speed With Which MEPs Can Detect Potential Ischemia?
During AVM Resection, EEG Slowing Is noted, Then a Global Decrease in MEP Amplitude Occurs, and Then This Is Followed by a Global Increase in SSEP Latency of Greater Than 10%. The Surgeons Are Notified of These Changes. What Do You Expect Is the Cause
MEPs, As Utilized in the Case Above, Give Real-Time Assessment of Primary Motor System Integrity. What Additional Monitoring Could Be Utilized If the AVM Was Located Within or in Very Close Proximity to the Primary Motor Cortex and/or the Corticospina
What Would an Alternative Anesthetic Technique Be for a Patient With an AVM Located in or Very Near the Motor and/or Language Cortex?
Postoperatively, If the Patient’s Mental Status Deteriorated, What Cause Particular to AVM Obliteration Should Be Considered? What Type of Neurological Monitor Might You Consider at This Point?
What Precautions Should Be Taken to Avoid NPPB?
Would the Management of an AVM Differ If the Patient Was Pregnant, and What Additional Monitoring Should You Consider?
References
23: Microvascular Decompression for Cranial Nerve Disorders
Introduction
Cranial Nerve Disorders from Vascular Compression
Trigeminal Neuralgia
Pathophysiology of Classical TN
Presentation of Clinical Scenarios
Case 1
What Was the Cause of This Change? Was It Surgical, Pharmacologic, Physiologic, Positional, or Technical?
Case 2
What Could Be the Cause?
Case 3
Is This a Significant Change?
What Is the Cause of This Change?
Case 4
What Happened? Is This Related to the Remifentanil Infusion, a Cardiac Incident, Brainstem Manipulation, or Something Else?
Case 5
What Is the Problem and What Should Be Done?
Case 6
Hemifacial Spasm
Electrophysiology and Pathophysiology of HFS
Anatomy of the Facial Nerve and Etiology of HFS
Imaging in HFS
Operative Technique of Microvascular Decompression of the Facial Nerve
Anesthetic Considerations During MVD for HFS
Principles of Intraoperative Neuromonitoring for HFS
Monitoring for Complications
Case Illustrations
Case 1: Understanding the AMR During MVD of the Facial Nerve
Case 2: “Frozen Shoulder” or Adhesive Capsulitis of the Glenohumeral Joint After MVD in the Contralateral Decubitus Position
Case 3: Hearing Loss as a Result of MVD for HFS
Case 4: Anesthesia and the AMR
Case 5: Stroke During MVD for HFS
Case 6: Facial Weakness and MVD for HFS
Case 7: Vestibular Nerve Dysfunction (After MVD for HFS)
Case 8: Dysphagia/Hoarseness Following MVD for HFS
Glossopharyngeal Neuralgia
References
24: Surgery for Extra-axial Infratentorial Mass and IOM
Introduction
Clinical Presentation of Tumors Located in the Infratentorial Compartment
Pathologies in Extra-Axial Surgery
Adult Patients
Pediatric Patients
Surgery and Workflow
Interdisciplinary Communication
Surgery and Surgical Approaches for Infratentorial Mass
Positioning
Surgical Approach
Anesthesia Considerations for Surgeries Within the Infratentorial Compartment
Intraoperative Neurophysiology for the Tumors Within the Infratentorial Compartment
Monitoring of Motor Cranial Nerves
Monitoring of Sensory Fibers of Cranial Nerves
Monitoring of the Auditory Nerves
Monitoring of the Somatosensory and Motor Pathways
Case 1. Resection of a Meningioma in the Right Cerebellopontine Angle
Which IOM modalities should you consider for this suboccipital surgery in the sitting position?
Anesthesia
Type of Anesthesia
Anesthesia for Brain Surgery in the Sitting Position
Neuromonitoring
Effects of the Surgical Resection
Postoperative Course
Surgical
Positioning of the Patient in the Sitting Position
Tumor Resection
Stimulation of the Facial Nerve
Case 2. Effect of Neuromuscular Blockade on EMG and DNS Recordings
Case 3
What should be considered for IOM in this case?
Intraoperative Neuromonitoring Course
Case 4
Intraoperative Neuromonitoring Course
Conclusions
References
25: Intraoperative Neurophysiology Monitoring for Intra-axial Posterior Fossa Surgery
Introduction
Anesthesia
Surgery of the Midbrain
Mapping
Corticospinal Tract Identification at the Level of the Cerebral Peduncle
Monitoring
Motor-Evoked Potentials
Brainstem Auditory-Evoked Potentials
Surgery of the Pons
Mapping of the Facial Colliculus on the Floor of the Fourth Ventricle
Facial Nerve Monitoring: Free-Running Electromyography
Facial Motor-Evoked Potentials
Surgery of the Medulla Oblongata
Mapping IX/X, XI, and XII Cranial Nerve Nuclei
Lower Cranial Nerve Monitoring
Lower Cranial Corticobulbar-Evoked Potentials
Brainstem Reflexes and Other Monitoring Techniques
Conclusion
References
26: Endoscopic Skull Base Surgery
Introduction
Perioperative Considerations
Goals of IOM During Skull Base Surgery
Modes of Neuromonitoring
Electromyography
Evoked Potentials (SSEP, MEP, VEP, ABR)
Case 1
Differential Diagnosis of ABR Findings
Case Progression
Case 2
Differential Diagnosis of SSEP Findings
Case Progression
Conclusion
References
27: IOM for Surgery Near the Extracranial Facial Nerve
Introduction
Anatomy of Facial Nerve
Methodology of CMAP Monitoring/Mapping
Recording Electrode Setup
Preoperative Mapping
Continuous CMAP Monitoring
Intraoperative Mapping
Warning Criteria and Correlation with Outcome
Comparison of Results for Various FN Monitoring Methods
Conclusions
References
28: The Techniques and Rationale of Intraoperative Monitoring for Perilaryngeal Surgeries
Introduction
Surgical Anatomy
Techniques of IONM
Anesthesia
Spontaneous Electromyography
Triggered Electromyography
Localization
Continuity
Viability
Prediction of Nonrecurrence
Continuous IONM
Automatic Periodic Stimulation
Laryngeal Adductor Reflex
Rationale of IONM
Inference of Protection
Systematic Procedures
Training for Health Professionals
Conclusions
References
29: Carotid Surgery
Introduction
Why Monitor During Carotid Surgery?
Monitors of Cerebral Ischemia During Carotid Surgery
Awake Patient
EEG
SSEP
MEP
Transcranial Doppler
Preoperative Considerations
Case 1
Case 2
Evaluation of Changes in Monitoring
Management of Changes
Postoperative Complications/Outcomes
Conclusions
References
30: Cervical Spine Surgery
Introduction
Case Presentations
Case 1
What Are the Possible Causes for the Diminished Baseline SSEP and MEP Signals in This Patient?
What Are the Possible Causes for the Diminished Left-Sided SSEP and MEP Signals at This Point in Time?
Case 2
What Could Be the Cause of This EMG Change?
MEPs Were Acquired and Revealed No Changes. SSEP Responses Were also Stable. How Should We Proceed?
Case 3
How Should the Airway Be Secured in This Patient? Should an Awake or Asleep Technique Be Used? Would Neuromonitoring, After Induction but Prior to Intubation, Be of any Value in This Case? What Neuromonitoring Modalities Should Be Used for This Case?
What Could Be the Cause of These Right Arm SSEP Changes? What Should Be Done to Correct These Changes and Avoid Injury?
What Could Be the Cause of This Global Change in Cortical SSEPs Alone?
What Might Be the Cause of This Type of Change in SSEPs?
Case 4
What Might Be the Cause of This Type of Change in SSEPs?
Conclusion
References
31: Surgery for Scoliosis
Introduction
IONM Modalities
Case Study
Summary and Conclusion
References
32: Surgery for Adult Deformity Correction
Introduction
Background and Pathogenesis
Identification and Classification
Surgical Goals and Approaches
Approaches to Instrumentation and Intraoperative Neuromonitoring
Anterior Approaches
Lateral Approaches
Posterior Approaches
Checklists and Protocols
Gain Control of the Room
Anesthetic/Systemic
Technical/Neurophysiologic
Surgical
Ongoing Considerations
Best Practice Guideline for IONM Practices
Case 1
Case 2
Discussion
Conclusions
References
33: IONM During Lumbosacral Spinal Fusion Procedures
Introduction
Basic Anatomy
Relevant Diagnoses and Procedure Specifics
Pedicle Screw and Nerve Root Testing: Interpreting Threshold Values
Modality-Specific Considerations
SSEP and MEP Alert Criteria Considerations
Therapeutic Impact Considerations
Anesthesia Considerations
Fusion Procedures
Posterior Lumbar Interbody Fusion (PLIF)
Transforaminal Lumbar Interbody Fusion (TLIF)
Anterior Lumbar Interbody Fusion (ALIF)
Lateral Lumbar Interbody Fusion (LLIF)
Oblique Lumbar Interbody Fusion (OLIF)
Conclusion
References
34: Intraoperative Neurophysiology During Intramedullary Spinal Cord Tumor Surgery
Preoperative Considerations
Clinical Picture
Tumor Features
Monitoring and Mapping Techniques
Monitoring Techniques
D Wave
Mapping Techniques
Patient Positioning and Baseline Determination
Surgical Technique
IONM Changes: Contributing Factors, Warning Criteria, and Reaction Strategies
Contributing Factors
Warning Criteria
Reaction Strategies
References
35: Surgery in the Peripheral Nervous System
Peripheral Nerve Anatomy and Injury Types
Electrodiagnostics and Peripheral Nerve Surgery
Anesthetic Considerations
Limitations of Electrodiagnostics
Conclusions
References
36: Aortic Intervention: A Practical Guide to Monitoring, Preventing, and Treating Spinal Cord Injury
Aortic Aneurysms
Management of Descending Thoracic and Thoracoabdominal Aortic Disease and Outcomes
Incidence and Risk Factors for Spinal Cord Ischemia
Spinal Cord Blood Supply
Pathophysiology of Spinal Cord Injury
Prevention of Spinal Cord Injury
Open Repair
Endovascular Repair
Cerebrospinal Fluid Drainage (CSFD)
Oxygen Delivery and Blood Pressure Management
Neuromonitoring
Motor- and Somatosensory-Evoked Potentials
Near-Infrared Spectroscopy
Liverpool Heart and Chest Hospital Spinal Cord Protection Approach
CSFD Insertion
Intraoperative CSFD Management
Postoperative Instructions
Analgesia
Response to Postoperative Spinal Cord Deficit
Acetazolamide
Intraoperative Spinal Cord Monitoring
Electrode Placement
Settings Used for Transcranial Motor-Evoked Potential
Baselines and Measuring Change
Tailoring Anesthetic Techniques
Interventional Approach and Motor-Evoked Potential Protocols
Intraoperative Algorithm
Open Thoracoabdominal Aortic Surgery with Cardiopulmonary Bypass and Deep Hypothermic Circulatory Arrest
Endovascular Stent Grafting
Leaving Theatre with no MEP Signals
Postoperative Management
MEP Troubleshooting
Signal Interference
Bilateral Loss of Limb Signals
Unilateral Change of Signals in Lower Limb
Clinical Example of MEPs
Conclusion
References
37: Neuroendovascular Procedures
Introduction
Major Vessels and Perfusion Targets
Types of Neuroendovascular Procedures and the Vascular Diseases They Treat
IONM Modality Planning
Alert Guidance in Diagnosing Ischemia
Anesthetic Management
Idiosyncrasies Associated with IONM During Neuroendovascular Procedures
Case Example 1: Balloon-Testing Occlusion (BTO)
Case Example 2: Right MCA Thrombectomy
Case Example 3: Provocative Testing of Anterior Choroidal Artery Aneurysm Associated with AVM
Case Example 4: Provocative Testing of Cervical Spinal AVM
Conclusion
References
38: Intraoperative Neuromonitoring in Pediatric Surgery
Introduction
Anesthetic Management of Pediatric Surgical Procedures That Require Intraoperative Neurophysiological Monitoring
Monitoring Modalities and Development
Somatosensory-Evoked Potentials
Transcranial Motor-Evoked Potentials
Electromyography
Electroencephalography
Brainstem Auditory-Evoked Responses
Bulbocavernosus Reflex
Common Pediatric Surgical Procedures Utilizing IONM
Posterior Spinal Fusion
Anesthetic Management During Spine Surgery
Dorsal Rhizotomy
Tethered Cord Release
Craniotomy for Tumor/Mass Lesion Resection
Conclusion
References
Suggested Reading
39: Neuromonitoring in the Intensive Care Unit for Treatment and Prognostication
Case 1: Traumatic Brain Injury
Clinical Application of ICP Monitoring
Cerebral Perfusion Pressure
Case 1 Continued: Paroxysmal Sympathetic Hyperactivity
Case 2: Subarachnoid Hemorrhage
Blood Pressure Monitoring
Case 2 Continued: Sodium and Fluid Shifts
Fluid Monitoring
Sodium Monitoring
Case 2 Continued: Vasospasm
Vasospasm
Monitoring for Angiographic Vasospasm
Case 2 Continued: Worsening Vasospasm
Brain Oxygenation Monitoring
Continuous EEG as a Monitor for Vasospasm
Case 3: Cardiac Arrest
Temperature Monitoring
Laboratory Monitoring: Potassium, Creatinine Clearance, Arterial Blood Gas, and Coagulation
Case 3 Continued: Myoclonus
Post Hypoxic Myoclonus
Case 3 Continued: Prognostication
Prognostication
Bedside Examination
Neurophysiology
Neuron-Specific Enolase
Neuroimaging
Case 4: Spinal Cord Injury
Neurologic Assessment
Respiratory Monitoring
Cardiovascular Monitoring
Case Continued: Spinal Cord Perfusion
Blood Pressure Augmentation
Case 5: Stroke
Cardiovascular Monitoring
Case Continued: Abnormal EEG
EEG Monitoring
Pupillometry
Case 6: Seizure
Duration of EEG Monitoring
Management of Seizures and Status Epilepticus
References
Index