Intraoperative Neuromonitoring

Description

Interoperative Monitoring, Volume 186 provides a concise overview of advances in interoperative monitoring targeted for clinical neurologists. It identifies techniques (EEG, ECoG, EMG, etc.), optimal anesthesia for use, safety issues to be considered, and then discusses advances as they relate to intracranial, spinal, peripheral nerve and vascular surgery. Best practices and case studies are included for all chapters as well as surgical microscope views, illustrations, and medical imaging. Front Cover Intraoperative Neuromonitoring Copyright Available titles Foreword Preface Contributors Contents General issues Chapter 1: Overview of intraoperative neuromonitoring History of Monitoring Technologist Staffing and Supervision Conclusions References Further reading Chapter 2: Electroencephalography, electrocorticography, and cortical stimulation techniques Electroencephalogram (EEG) The electrophysiology of the EEG signals Methodology Interpretation Clinical applications in the OR Anesthesia considerations Electrocorticography Introduction Physics and physiology Methodology Interpretation Clinical applications Epilepsy surgery Temporal lobe epilepsy Frontal cortical dysplasias High-frequency oscillations (HFO) Non-epilepsy surgery Anesthesia considerations Cortical Stimulation Techniques Physics and physiology of electrical stimulation Patient safety Current density Pulse features Electrode material and geometry Stimulation triggered after discharges and seizures Stimulation methods Constant voltage versus constant current stimulation Stimulus polarity Efficient depolarization of the alpha motor neurons Type of stimulation Monopolar cortical stimulation Bipolar cortical stimulation Types of stimulating electrodes Stimulation paradigms used in clinical practice Penfield or low-frequency paradigm (Fig. 2.8A) Very low-frequency stimulation The dual paradigm technique Multipulse train method (Fig. 2.11) References Chapter 3: Intraoperative evoked potential techniques Introduction Basic Principles Evoked potential generation Averaging, reproducibility, and signal-to-noise ratio Unaveraged evoked potentials Stimulus properties Electrodes Cable management Recording and technical parameters Interpretation and Analysis Somatosensory Evoked Potentials Anatomical considerations Anatomical controversies Nondecussation Stimulation technique Anesthesia Traditional SEP monitoring derivations SEP optimization Upper limbs Lower limbs Omitted and optional potentials Benefits of SEP optimization SEP warning criteria SEP mapping Cortical SEP mapping Dorsal column SEP mapping Motor Evoked Potentials Anatomical considerations Nondecussation Physiologic basis Stimulation technique Current or voltage Pulse duration Strength–duration Pulse number Interstimulus interval Facilitation Anode and cathode selection Anesthesia D-wave recording Muscle MEP recording D-wave warning criteria Muscle MEP warning criteria MEP mapping Cortical MEP mapping Subcortical MEP mapping Spinal cord MEP mapping Brainstem Auditory Evoked Potentials Anatomy and physiology Stimulation technique BAEP recording Warning criteria and indications Visual Evoked Potentials Anatomy and physiology Stimulation Recording Anesthesia Warning criteria and interpretation Conclusion References Chapter 4: EMG monitoring Introduction History Physiology Methodology Facial Nerve Outcome Prediction and Traintime Suprasegmentally Generated EMG Discharges (SEDs) References Chapter 5: Safety issues during surgical monitoring Introduction Electric Safety Electric connections with the patient Effects of electric currents Electric shock Functional physiologic activation Cardiac failure Conditions for electric activation of the heart muscle and nerve tissues Physic effects of electric currents in general Electric heating Influence of electrode insertion Heat drainage Thermal toxicity Protection against thermal injury Specific effects from stimulation Temperature effects Effects of heat drainage Accuracy of stimulators Optimization of the pulse width TES-induced parasitic current conduction along with physiologic amplifiers Prevention of parasitic conduction TES in skull defects and neonate anatomy Direct cortical stimulation and excitotoxicity Complications from TES muscle contractions Bite injuries Movement-induced injury Seizures and after discharges MEP and implanted devices Invasive electrode complications Equipment-Related Safety Issues Leakage currents Means of protection against electric shock Single fault safe Leakage current limits Periodic inspection Power cords and lead connectors Conclusions Acknowledgments References Intracranial surgery Chapter 6: Neurophysiology during epilepsy surgery Introduction Epileptic Focus Mapping The epileptogenic lesion The epileptogenic zone The seizure onset zone The irritative zone Intraoperative ECoG Technique Interpreter Anesthesia New approaches to intraoperative epileptic focus mapping High-frequency oscillations Single-pulse electric stimulation Functional Mapping Penfield technique Penfield technique drawbacks Evoked potential mapping Somatosensory evoked potentials Motor evoked potentials Visual evoked potentials Cortico–cortical evoked potentials Long latency laryngeal muscle responses Functional Monitoring Somatosensory evoked potentials Motor evoked potentials Other evoked potentials Conclusion References Chapter 7: Neurophysiology during movement disorder surgery Introduction Microelectrode Techniques Local Field Potentials General Stereotactic Technique Internal Globus Pallidus Procedures Subthalamic Nucleus Procedures Data Analysis Conclusion References Chapter 8: Intraoperative mapping and monitoring during brain tumor surgeries Introduction and Neurooncologic Considerations Technical Considerations, Methods, and Set-Up for Asleep and Awake Surgeries Prerequisites for awake craniotomy Preparation for direct cortical stimulation Neurophysiologic methods Motor evoked potentials Direct cortical stimulation techniques Somatosensory evoked potentials Visual evoked potentials Monitoring in Supratentorial Surgery Surgical steps related to nonspecific evoked potential changes Feasibility of SEP and MEP monitoring in glioma surgery Critical surgical steps causing changes in evoked potentials Correlation of MEP and SEP signal changes to neurologic outcome MEP warning criteria Cortical Mapping During Supratentorial Surgery Under General Anesthesia Subcortical Mapping for the Corticospinal Tract During Surgery Under General Anesthesia Sensory–Motor Integration and Praxis Circuits Language and Cognitive Mapping During Awake Surgeries Summary References Chapter 9: Mapping and monitoring of brainstem surgery Introduction Indication and Anesthetic Considerations Mapping Techniques Mapping of the facial colliculus and safe entry zone in the fourth ventricle floor Stimulation set up Recording technique Illustrative case Mapping of other cranial nerve nuclei Mapping of the corticospinal tract Limitations of mapping technique Monitoring Techniques Motor evoked potentials Stimulation set up Recording Corticobulbar MEPs Stimulation Recording Free-running electromyography Brainstem auditory evoked potentials Somatosensory evoked potentials Intraoperative Monitoring Pitfalls Optimal Response to Critical IONM Change Remember ``TIPs´´ Conclusion References Chapter 10: Monitoring cerebellopontine angle and skull base surgeries Introduction Methods Mapping intracranial part of CNs Monitoring Brainstem auditory evoked potentials (BAEP) Somatosensory evoked potentials (SEPs) Motor evoked potentials Free running EMG for CNs monitoring Corticobulbar MEPs (CoMEPs) (a). Stimulation parameters (b). Recording parameters Facial nerve Lower cranial motor nerves Pitfalls in CBT monitoring Brainstem reflexes Blink reflex Masseteric reflex Laryngeal adductor reflex Intraoperative Neuromonitoring During MVD for Hemifacial Spasm Methodology for intraoperative monitoring the HFS Auditory brainstem responses (ABR) Lateral spread (LSR) FCoMEPs Blink reflex (BR) Conclusion References Spinal surgery Chapter 11: Monitoring scoliosis and other spinal deformity surgeries Scoliosis and Kyphosis Complications of Spinal Deformity Surgery Cervical Myelopathy Natural history Clinical presentation Surgery for Cervical Myelopathy Basis for Intraoperative Neurophysiologic Monitoring During Cervical and Thoracic Spinal Surgery Animal work Patient experience Techniques for Intraoperative Neurophysiologic Monitoring During Cervical and Thoracic Spinal Surgery Somatosensory evoked potentials Stimulation Recording Alarm criteria Motor evoked potentials Stimulation Recording Alarm criteria Electromyography IONM team References Further reading Chapter 12: Intraoperative neuromonitoring during surgery for lumbar stenosis Introduction Pathoanatomic and Clinical Considerations in Lumbar Stenosis Surgical Approaches and Associated Neural Risks Evidence-Based Medicine and IONM in Lumbar Stenosis/Spine Surgery Pedicle screw threshold testing: An update Does MEP monitoring have a role in extradural lumbosacral surgery? IONM in lumbosacral deformity and high-grade spondylolisthesis IONM in TLIF and ALIF IONM in LLIF and OLIF IONM Methods during Lumbar Stenosis Surgery Reflections on the IONM evidence base in extradural lumbosacral spine surgery References Chapter 13: Intraoperative neurophysiology in intramedullary spinal cord tumor surgery Background Why to Use Intraoperative Neurophysiology? Clinical Presentation of ISCTs Anesthesia for IONM Intraoperative Neurophysiological Monitoring Techniques Somatosensory evoked potentials Muscle motor evoked potentials D-wave Intraoperative Neurophysiological Mapping Techniques Dorsal column mapping Mapping of the corticospinal tract Neuromonitoring-Guided Surgery Illustrative case IONM and evidence-based medicine Conclusions References Chapter 14: Monitoring spinal surgery for extramedullary tumors and fractures Introduction Indication for Monitoring Clinical classification and presentation Spine extramedullary tumor Spine fracture Indication for surgical treatment Surgical treatment Surgical treatment for extramedullary tumor Surgical treatment for spine fracture Risk of nervous system injury during surgery Role of Intraoperative Neurophysiology Preservation and prediction of spinal cord function Mapping and monitoring spinal nerve root function Monitoring modalities Motor evoked potentials Somatosensory evoked potentials The bulbocavernosus reflex Electromyography Compound muscle action potentials Anesthesiologic considerations IONM and Outcomes for Spinal Extramedullary Tumors And Fractures Conclusion References Chapter 15: Mapping and monitoring of tethered cord and cauda equina surgeries Anatomy of the Pelvic Floor and Clinical Symptoms in Tethered Cord Syndrome Mapping and Monitoring Techniques Monitoring techniques Somatosensory evoked potentials Motor evoked potentials Electromyography Anal sphincter EMG Bulbocavernosus reflex Mapping techniques Mapping of the cauda equina Spinal cord stimulation Limitations of Mapping and Monitoring Techniques in the Area of the Pelvic Floor Complications and Clinical Outcomes After Tethered Cord Repair Conclusion References Chapter 16: Dorsal root entry zone procedure and other surgeries for pain Introduction Anatomy of Pain Classification of Surgeries for Pain Ablative surgeries Augmentative surgeries NIOM for Pain Surgeries DREZ procedure Spinal cord DREZ procedure Nucleus caudalis DREZ procedure Trigeminal rhizotomy Motor cortex stimulation Spinal cord stimulation Dorsal root ganglion stimulation Other surgeries for pain Future Directions Conclusion References Peripheral nerve surgery Chapter 17: Neurophysiology during peripheral nerve surgery Introduction Preoperative Evaluation IONM Modalities Nerve conduction studies Somatosensory evoked potentials Motor evoked potentials Electromyography IONM for Specific Disorders Peripheral nerve tumors Entrapment neuropathies Selective fascicle biopsy Peripheral nerve trauma and brachial plexus injury Prevention of peripheral nerve injuries during surgical procedures Technical/Interpretation Issues Summary References Chapter 18: Monitoring surgery around the cranial nerves Introduction History Monitoring Techniques Spontaneous and triggered EMG Recording electrodes Recording techniques EMG findings during IONM Triggered EMG recordings Anesthesia and EMG monitoring Motor evoked potentials Somatosensory evoked potentials Brainstem auditory evoked potentials Cranial nerve reflexes Cranial Nerves Monitoring of extraocular muscle function (CNs III, IV, and VI) Function EMG Recording and Stimulation Techniques CN V (trigeminal nerve) Functions and anatomy Monitoring sensory function CN VII (facial nerve) Functions and anatomy EMG monitoring Facial nerve motor evoked potentials IONM of facial nerve function using F waves Lateral spread reflex Facial nerve IONM acceptance and guidelines CN VIII (vestibulocochlear nerve) Functions and anatomy BAEP monitoring applications CN IX (glossopharyngeal nerve) Functions and anatomy IONM of CN IX CN X (vagus nerve) Functions and anatomy EMG monitoring of CN X Other techniques for monitoring CN X CN XI (accessory nerve) CN XII (hypoglossal nerve) Summary References Vascular surgery Chapter 19: Monitoring in carotid endarterectomy Introduction Anatomic, Physiologic, Clinical, and Surgical Considerations Collateral cerebral blood supply and cerebral autoregulation Predictors of intraoperative cerebral ischemia and the risk of perioperative stroke Carotid endarterectomy—Surgical techniques Critical steps of the procedure Intraoperative Neurophysiologic Monitoring for Detection of Cerebral Ischemia in Carotid Endarterectomy Electroencephalogram Methodology Alarm criteria for raw EEG analysis Quantitative EEG analysis Somatosensory evoked potentials Pros and cons of multimodality CEA monitoring Combined EEG and SEP monitoring Adding transcranial motor evoked potentials Anesthesia considerations EEG monitoring SEP/tcMEP monitoring Other Monitoring Techniques for Detecting Cerebral Ischemia TCD Stump pressure Cerebral oximetry Conclusion References Chapter 20: Surgery and intraoperative neurophysiologic monitoring for aneurysm clipping Introduction to Cerebrovascular Surgery History The neurophysiologist's view on aneurysm surgery The neurosurgical view on aneurysm surgery Unruptured aneurysms Aneurysm rupture rate Morbidity and mortality of unruptured aneurysms Treatment options and preferred treatment Neurophysiologic Methods Brainstem auditory evoked potentials Somatosensory evoked potentials Motor evoked potentials Visual evoked potentials Technical Considerations for IONM in Cerebral Aneurysm Procedures—Set-up in the Operating Room Anesthesia General considerations Interaction between participating teams in aneurysm surgery Vascular Territories and Recommended Recordings Anterior circulation aneurysms Posterior circulation aneurysms Specific Surgical Steps in Aneurysm Surgery Temporary clipping Surgical reaction on IOM alteration and duration of monitoring Comparison to other methods Signal deterioration and neurologic outcome Socioeconomic aspects and evidence Conclusion References Chapter 21: Monitoring cardiac and ascending aortic procedures Introduction Monitoring During Cardiac Operations Pathophysiology of neurologic injury On-pump procedures Off-pump procedures Critical events during cardiac operations Specific monitoring modalities Possible interventions Monitoring During Ascending Aortic/Aortic Arch Procedures Basic anatomy and pathophysiology Circulation management strategies and IONM Deep hypothermic circulatory arrest Selective antegrade cerebral perfusion Retrograde cerebral perfusion Methods of cardiopulmonary bypass Critical events during aortic arch repair Arrival Initiation of anesthesia to the initiation of CPB Initiation of CPB to the beginning of the aortic repair During the period of aortic repair After the repair Specific monitoring modalities Conclusions References Chapter 22: Neuromonitoring during descending aorta procedures Introduction The Vascularization of the Spinal Cord: Anatomy and Hemodynamics of the Spinal Cord Arterial Network Preoperative Planning Assessment of the vascular anatomy Choosing an operative approach: Open vs endovascular TAA repair Open TAA Repair Open TAA repair via the clamp-and-sew technique Cerebrospinal fluid drainage Regional spinal cord hypothermia Open TAA repair with distal aortic perfusion and neurophysiologic monitoring Maintaining adequate distal aortic perfusion Sequential clamping of the aorta and prevention of the steal phenomena Multimodality neurophysiologic monitoring Neurophysiologic changes in SCI SEPs vs MEPs Differences in blood supply: gray vs white matter Amplitude alarm criteria for MEPs Neurophysiologic changes in limb ischemia Neurophysiologic changes in cerebral ischemia Key points in neurophysiologic monitoring Obtaining reliable baselines Choice of anesthetics Safety of MEPs After exposure and before the start of DAP Proximal aortic cross-clamping Distal aortic cross-clamping, below the origin of the segmental arteries Clamping distal to the origin of the pelvic visceral arteries Closing and postoperative course Delayed Paraplegia Conclusions References Back Cover