UPDATED REVIEW IN NEUROSURGICAL ANESTHESIOLOGY AND NEURO-CRITICAL CARE

RAMSIS F. GHALY, MD, FACSDEPARTMENT OF ANESTHESIOLGY

AND PAIN MANAGEMENT, ADVOCATE ILLINOIS MASONIC

MEDICAL CENTER GHALY NEUROSURGICAL

ASSOCIATES

NEUROANATOMY AND NEURORADIOLOGY RVIEW FOR

THE ANESTHESIOLOGIST

RAMSIS F. GHALY, MD, FACS

HEAD, BRAIN AND CRANIAL NERVES

Anatomy of the BrainAnatomy of the Brain• Approximately 2% of total body weight• Weighs 1400g in average young adult• Weighs 1200g in average elderly person• Major divisions

• Cerebrum• 2 hemispheres• Thalamus• Hypothalamus• Basal Ganglia

–Brain Stem•Midbrain

•Pons

•Medulla

–Cerebellum•Located under the cerebrum and behind the brain stem

MeningesMeninges

• Dura Mater• Outermost layer, covers the brain and

spinal cord• Tough, think, inelastic fibrous, gray• Epidural space is between the skull

and the dura mater• Subdural space is between the dura

mater and the arachnoid mater• Several folds of the dura mater

MeningesMeninges

• Arachnoid layer• Middle membrane• Closely resembles a spider web• Responsible for production of CSF • Substantial vascular supply• Subdural space is between the dura

and the arachnoid layer• The subarachnoid space is located

between the arachnoid and pia layers and contains the CSF

Cerebrum – Lobes of Cerebrum – Lobes of brainbrain

• Frontal• Personality• Behavior• Intellectual

functions• Short-term

memory• Voluntary motor

function• Motor speech

(Broca’s area)

• Parietal• Localization• Sensory integration/

discrimination• Object recognition• Position sense• Body awareness• Body image

Cerebrum – Lobes of Cerebrum – Lobes of brainbrain

Temporal• Emotion• Processing smell,

hearing, tastes• Sensory speech

Occipital• Processing visual

input

Brain StemBrain Stem• Functions

• Relays messages between the brain and lower levels of the nervous system

• Is the origin of all cranial nerves except 1st and 2nd

Brain StemBrain Stem• Midbrain (Mesencephalon)

• Connects the pons and cerebellum with the cerebral hemispheres

• Center for auditory & visual reflexes• Origin of 3rd and 4th cranial nerves• Contains motor and sensory pathways• Location of reticular activating system

(RAS)• Responsible for arousal from sleep,

wakefulness, focusing of attention

CerebellumCerebellum• Coordinates muscle movement

with sensory input• Controls balance• Influences muscle tone in relation

to equilibrium• Affects locomotion and posture• Controls non-stereotyped

movements• Synchronizes muscle action

NeuronsNeurons• Dendrites

• Message-receiving

• Cell body• Axons

• Message-sending

• Both are branching fibers that reach out in many extensions to join the neuron to other neurons

• The junction between the axon of one cell and the dendrite of another is a minute gad, which is called a synapse

NeurotransmittersNeurotransmitters

• Communication at the synapses between neurons relies on chemicals called neurotransmitters

• More than 50 different neurotransmitters identified

• Proposed that almost all drugs work through neurotransmitters

Blood Brain BarrierBlood Brain Barrier• Not a true structure, but is a special

permeability characteristic of brain capillaries and choroid plexus

• Functions• Acts to limit transfer of certain substances

into ECF or CSF of the brain• May hinder the effective use of certain drug

therapies in the treatment of neurologic system problems

• May be altered by trauma, infection, intracranial tumor, brain irradiation

Cerebral CirculationCerebral CirculationAnterior Circulation

(Internal Carotid)

• Anterior Cerebral• Frontal & parietal lobes

(superior surface)• Basal ganglia• Corpus callosum• Hypothalamus

• Middle Cerebral• Parietal, frontal, &

temporal lobes (lateral surfaces

• Superior surface of temporal lobe

Posterior Circulation(Vertebral system)

• Basilar arteries• Most of brain

stem• Cerebellum

• Posterior cerebral arteries• Thalamus• Medial portion of

occipital• Inferior portion of

temporal

Venous SystemVenous System

• Cerebrum has external veins that lie in the subarachnoid space on surfaces of hemispheres and internal veins that drain the central core of the cerebrum and lie beneath the corpus callosum

• Both external and internal venous systems empty into venous sinuses that lie between dural layers

• The internal jugular veins collect blood from the dural venous sinuses

CTSCAN: BRAIN TUMOR

AP C-SPINE X-RAY

SYMPATHETIC SYSTEM

• SYMPATHETIC, PREGANGLIONIC FIBERS ARISE FROM THE THORACOLUMBAR PORTION OF THE SPINAL CORD FROM FIRST THORACIC TO THIRD LUMAR SEGMENT OF THE SPINAL CORD

• PREGANGLIONIC FIBERS HAVE CELL BODIES WITHIN INTERMEDIOLATERAL COLUMNS OF THE SPINAL GRAY MATTER.

• NERVE FIBERS FROM THESE CELL BODIES EXTEND TO 3 TYPES OF GANGLIA, PAIRED SYMPATHETIC CHAINS, UNPAIRED DISTAL PLEXUSES OR TERMINAL/ COLLATERAL CLOSE TO TARGET ORGAN.

• AUTONOMIC GANGLION, A NUMBER OF CELL BODIES ACT AS SYNAPSE BETWEEN PREGANGLIONIC AND POSTGANGLIONIC FIBERS

• 22 PAIRED GANGLIA ALONG EITHER SIDE OF THE SPINE. NERVE TRUNKS CONNECT THESE GANGLIA TO EACH OTHER AND GRAY RAMI COMMUNICANTES TO THE SPINAL NERVES

SYMPATHETIC SYSTEM

• PREGANGLIONIC FIBERS LEAVE ANTERIOR NERVE ROOTS → SPINAL NERVE TRUNK→ GANGLION THROUGH WHITE MYELINATED RAMUS POSTSYNAPTIC FIBERS → SPINAL NERVE THROUGH GRAY RAMUS → PILOMOTOR, SUDOMOTOR EFFECTORS, BLOOD VESSELS, SKELETAL MUSCLE AND SKIN

• SYMPATHETIC INNERVATION OF TRUNK AND LIMBS CARRIED BY SPINAL NERVES

• POSTGANGLIONIC SYMPATHETIC FIBERS ARE DISTRIBUTED THROUGHOUT THE BODY.

• HEAD AND NECK SUPPLIED BY CERVICAL SYMPATHETIC CHAIN THREE GANGLIA (SUPERIOR, MIDDLE AND INFERIOR)

SYMPATHETIC SYSTEM

• STELLATE GANGLION IS FORMED BY FUSION OF INFERIOR CERVICAL GANGLION WITH FIRST THORACIC GANGLION

• UNPAIRED PREVERTEBRAL GANGLIA RESIDE IN ABDOMEN AND PELVIS ANTERIOR TO VERTEBRAL COLUMN: CELIAC, SUPERIOR MESENTERIC, AORTICORENAL AND INFERIOR MESENTERIC GANGLIA

• CELIAC GANGLION INNERVATED BY T5 THROUGH T12

PARASYMPATHETIC SYSTEM• PARASYMPATHETIC, PREGANGLIONIC FIBERS ARISE FROM THE

CERVICOSACRAL PORTION OF THE SPINAL COIRD. IT ARISES FROM CRANIAL NERVES III, VII, IX, AND X. PREGANGLIONIC FIBERS ARISE FROM MIDBRAIN (EDINGER-WESTPHAL N.), MEDULLA OBLONGATA. PARASYMPATHETIC SACRAL TWO TO SACRAL FOURTH SEGMENTS TO PELVIC SPLANCHNIC NERVES.

• WHILE DISTRIBUTION OF PARASYMPATHETIS IS DISCRET AND CLOSE TO THE ORGANS INNERVATED

PERIPERAL AUTONOMIC NERVOUS SYSTEM• SYMPATHETIC NOREPINEPHERINE AS A

NEUROTRANSMITTER (ADRENERGIC). ADRENERGIC RECEPTORS (BETA, ALPHA)

• PARASYMPATHETIC ACETYLECHOLINE AS NEUROTRANSMITTER (CHOLINERGIC) NICOTINIC AND MUSCARINIC RECEPTORS

AIRWAY MANAGEMENT

FIELD ENJOYED MANY CHANGES AND NEW TECHNIQUES HAVE DEVELOPED AS WELL AS BEING DEVELOPED

POSITIVE IMPACT ON AIRWAY SAFTEY AND THE OVERALL CLAIMS DUE TO IRREVERSIBLE ANOXIC BRAIN DAMAGE FROM

AIRWAY OPTIONS

• CONVENTIONAL • TO AVOID ↑ICP→ MUST BE DEEPLY ANESTHETIZED MUST USE FULL NEUROMUSCULAR BLOCKADE MAINTAINING GOOD OXYGENATION MAINTAINING PACO2= OR <35 CONSIDER LOCAL ANESTHETIC SPRAY AND IV LIDOCAINE• AIRWAY VISUALIZATION DIRECT LARYNGOSCOPY - VIDEO LARYNGOSCOPY FIBEROPTIC SCOPE• INTUBATION USING REGULAR ENDOTRACHEAL TUBE

AIRWAY OPTIONS

INDIRECT LARYNGOSCOPY• SMOOTH LESS TRAUMA TIC LESS STIMULANT LESS COUGH LESS

C-SPINE MANIPULATION

• TYPES: LMA- LMA PROSEAL- FASTRACH INTUBATING LMA- VIDEO

LARYNGOSCOPIC LMA- LMA WITH FIBEROPTIC CONNECTION

• EXAMPLES WHEN TO USE IN NEUROANESTHESIA: INTERMITTENTLY DURING AWAKE CRANIOTOMY NEURORADIOLOGY ECT, DBS SURGERY TO REPLACE ETT JUST BEFORE EMERGENCE AS A TRANSITION FROM

ETT TO PREVENT COUGHING AND ALLOW SMOOTH EMERGENCE

AIRWAY MANAGEMENT: OPTIONS FOR DIFFICULT INTUBATION

REMEMBER AVAILABLE READY HANDY• AWAKE LARYNGOSCOPY• AWAKE LMA FASTRACH• AWAKE FIBEROPTIC SCOPE• AWAKE VIDEO LARYNGOSCOPY• AWAKE BLIND NASAL INTUBATION• THE GUM ELASTIC BOUGIE• THE LIGHT WAND• RETROGRADE TRACHEAL INTUBATION• RIGID BRONCHOSCOPY• COMBITUBE (ESPHOGEAL INTUBATION) CAN BE PLACED IN ANY POSITION, NO

NEED FOR LARYNGOSCOPY OR NECK MANIPULATION.• TRANSTRACHEAL JET VENTILATION• INVASIVE AIRWAY ACCESS

CRICOTHYROIDOTOMY - TRACHEOSTOMY OPEN OR PERCUTANEOUS AT BEDSIDE

THE END

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