Transcript Neurosurgery - A

Neurosurgery
Outline
•
•
•
•
•
•
•
•
A&P
Pathology
Diagnostics/Pre-operative Testing
Medications/Anesthesia
Positioning/Prepping/Draping
Supplies/Instrumentation/Equipment
Dressings/Drains/Post-op Care
Procedures: Carpal Tunnel Release,
Craniotomy, Cervical Discectomy, Lumbar
Discectomy, Ventroperitoneal Shunt
Nervous System
•
•
•
•
Functions:
Senses changes in environment
Interprets changes
Stimulates movement to respond to
these changes
Organization of the
Nervous System
• Two systems:
1. CNS Central Nervous System
• Two major parts: Brain and Spinal
Cord
2. PNS Peripheral Nervous System
• Everything else
Peripheral Nervous
System
• Two major parts:
• Afferent Nervous System
• Sensory neurons take info from PNS
to CNS
• Efferent Nervous System
• Motor neurons take info from CNS to
PNS
Efferent Nervous
System
•
•
1.
•
•
2.
•
•
•
•
•
Motor nervous system
2 parts:
Somatic Nervous System
Skeletal muscle control
Conscious control
Autonomic Nervous System
Cardiac muscle, smooth muscle, and glands
Unconscious control
Has 2 divisions:
Sympathetic Division
Parasympathetic Division
Autonomic Nervous
System
• Sympathetic vs. Parasympathetic
• Controlled by hypothalamus and medulla oblongata
• Both are different nerves going to the same
effector or target
• Are antagonistic
• Parasympathetic = decreased skeletal blood flow,
increased organ blood flow (quietly eating)
• Sympathetic = increased skeletal blood flow,
decreased organ blood flow (eatus interruptus by
a bear!) Also called fight or flight; prepares body
for emergencies
Spinal Cord
• Functions:
• Info to and from the brain
• Integration of reflexes
• Location:
• Begins at foramen magnum and
extends to 2nd lumbar
• About 16-18” in length
Spinal Cord Support
Structures
•
•
•
•
•
•
•
Vertebra
33 total
7 cervical
12 thoracic
5 lumbar
Sacrum formed by 5 fused bones
Coccyx formed by 4 fused bones
Intervertebral Disks
• Separate vertebrae
• Outer layer is tough and called the
annulus fibrosis
• Inner core is soft and called the
nucleus pulposus
• Bear stress incurred with body
weight and when lifting
Spinal Cord Support
Structures
•
•
•
1.
•
2.
•
3.
•
Meninges
Between vertebra & spinal cord
Epidural space between vertebra and dura
mater
Dura Mater outermost layer extends to S-2
Subdural space between dura mater and
arachnoid
Arachnoid extends to S-2
Subarachnoid space contains CSF
Pia Mater adheres directly to spinal cord and
extends to L-2
Meninges also cover brain/continuous
layer/difference epidural space not present
Spinal Nerves
• 31 pair
• Names and numbers depend on where enter and
exit
• Each has a ventral and dorsal root
• Ventral root = motor
• Dorsal root = sensory
• 8 cervical
• 12 thoracic
• 5 lumbar
• 5 sacral
• 1 coccygeal
Brain
• Protected by the cranium or skull
Brain
•
•
•
•
•
4 major parts:
Brain stem
Diencephalon
Cerebellum
Cerebrum
Weight about 3 lbs.
Support Structures of
the Brain
1. Meninges
• Continuous layer with spinal cord
• NO epidural space
Support Structures of
the Brain
2. Cerebrospinal fluid (CSF)
• About 800ml produced each day by the
choroid plexus, a specialized set of
capillaries
• Circulates inside subarachnoid space
through central canal of spinal cord and
the ventricles of the brain
• Reabsorbed in arachnoid villus found in the
parietal lobe
• Functions as a shock absorber and
circulates nutrients
Support Structures of
the Brain
3. Blood Brain Barrier
• Specialized set of capillaries exclusive to
the central nervous system
• Less permeable than any other capillaries
in the body
• Advantage = keeps out unwanted
chemicals
• Disadvantage = difficult to diffuse
materials out, hence difficulty in
treating conditions such as encephalitis
Brain Stem
•
•
•
•
3 parts:
Medulla oblongata
Pons
Midbrain
Medulla oblongata
• Contains:
• 5 of 12 cranial nerves
• Pyramids: function only with motor
neurons/a crossing of the spinal nerve
impulses
• Reflex centers: hiccupping, sneezing,
coughing
• Vital reflex centers:
• Cardiac center – heart rate
• Vasoconstrictor center-BP via blood vessel
diameter control
• Respiratory center - breathing
Pons
• Above medulla
• Switching point for motor neurons
• Respiratory center
Midbrain or
Mesencephalon
• Above pons
• Involuntary eye and head movement
in response to auditory stimuli
Diencephalon
• 2 parts:
• Thalmus
• Hypothalmus
Thalmus
• Relay center for sensory information
• Interprets stimuli for example pain
from changes in temperature (hot
stove)
• 1st level of reasoning occurs here
• Recognizes crude touch NOT
localized touch
Hypothalmus
• Controls large number of subconscious
functions
• Controls most of Autonomic nervous
system
• Where endocrine and nervous systems
interface
• Homeostasis regulation of the body
• Controls: body temp, thirst, hunger, sleep
and waking habits, psychosomatic
disorders, rage and aggression
Cerebellum
•
•
•
•
2nd largest part of the brain
Primarily a motor area
Controls skeletal muscles, subconsciously
Receives sensory input from eyes, muscles,
joints, and inner ear
• Posture, balance, coordination, equilibrium
• Muscle sense tells body where other parts
are
Cerebrum
• Largest part of brain
• Motor/sensory/association area
• 4 Lobes: frontal, parietal, occipital,
temporal
• Each controls a specific function be
it motor or sensory
• Limbic system: controls
emotion/functions in cerebral cortex
and diencephalon
• See page 970 Figure 24-4 in Price
Cerebrum Lobes’
Function
• Frontal
• Memory, abstract
thinking, ethics,
judgement,
emotion,
expressive speech,
motor
• Parietal
• Sensory, receptive
speech, written
word
•
•
•
•
•
Temporal
Auditory, olfactory
Occipital
Visual cortex
Visual association
Cranial Nerves
• All originate in the brain stem
EXCEPT the 1st and 2nd
• Classified as sensory or mixed
(sensory and motor) nerves
• Directly off of brain
• Do not go through the spine
• Identified by Roman numerals and
names
Cranial Nerves
I.
II.
III.
IV.
V.
VI.
Olfactory - sense of smell
Optic – sense of sight/vision
Occulomotor – eyeball, eyelid movement (medial,
inferior, superior rectus, inferior oblique), pupil
constriction, lens accommodation
Muscle sense for eyeball
Trochlear – eyeball movement (superior oblique)
Muscle sense for eyeball
Trigeminal – masseter muscle control
Sensory part has 3 branches: ophthalmic (forehead to
corner of eye), maxillary (corner of eye to upper
lip/teeth), and mandibular (lower lip/teeth/tongue)
All three convey sense of touch, pain and temp changes
Abducens - same as IV eyeball movement (lateral
rectus) and eyeball muscle sense
FYI:
EOM formula LR6(SO4)3
Cranial Nerves
VII.
Facial- facial muscles, lacrimal and salivary glands
anterior 2/3 of tongue (taste)
VIII. Vestibulocochlear -last of totally sensory nerves; has 2
branches: vestibular conveys balance and cochlear
which conveys sense of hearing
IX.
Glossopharyngeal -salivary gland secretion and posterior
1/3 of tongue
X.
Vagus – internal organ control motor and sensory;
originates in medulla and goes down through neck into
chest and abdomen
XI.
Accessory – controls head and neck movement, speech,
and muscle sense for the head
XII. Hypoglossal – tongue muscles: swallowing, speech, muscle
sense for tongue
Neuro Pathology
Cervical Spine Pathology
• Very serious
• Can have severe consequences related to
all of the spinal cords’ nerve pathways
• Spondylosis is osteophyte or bone spur
formation in the spinal canal
• Cervical disk extrusion acute or chronic
• Treatment errs on the side of caution due
to potential extreme consequences of
surgical intervention
Thoracic Pathology
• Spondylosis
• Extrusion of disk
Lumbar Pathology
•
•
•
•
Spondylosis
Stenosis
Spondylolithesis
Disk extrusion
Neoplasms/Tumors
• Two types:
• Primary
• Originate in nervous tissue or
meninges
• Secondary
• Are metastasized from other parts
of the body
• May be classified as benign or
malignant
Tumors
• Benign tumors:
• “Craniopharyngiomas, epidermoids, hemangiomas,
menigiomas, acoustic neuromas, and pituitary
microadenomas”
• Malignant tumors:
• “Astrocytes or gliomas”
Price, 2004
Price, 2004
• Benign usually excisable via craniotomy
• Malignant normally cannot be completely removed
but efforts are made to remove most
Head Trauma
• Includes;
• Scalp lacerations, fractures,
hematomas (epidural or subdural),
and brain injuries
Spinal Cord Trauma
•
•
•
•
Vertebral Fracture
Vertebral Dislocation
Herniated disk into spinal canal
Laceration from GSW or MVA
Cerebrovascular Disease
• #3 cause of death in US
• Symptoms reflect ischemia (TIAs) or
hemorrhage
• Intracranial aneurysm
• Arteriovenous malformations
• Brain hemorrhage
• Stroke or cerebrovascular accident
(CVA)
Congenital Pathology
• Craniosynotosis “premature closure
of the
cranial sutures”
• Hydrocephalus result of obstructed
CSF flow
• Spina bifida
Price, 2004
Infection
• Abscess
• Subdural empyema
• Post-op infection
Spinal Cord Tumors
• Intramedullary in the spinal cord
• Intradural in dura, outside spinal
cord
• Extradural outside spinal cord
Price, 2004
Peripheral Nerve
Pathology
• Carpal tunnel syndrome - compression
of the median nerve
• Ulnar nerve compression –
compression of ulnar nerve by the
ligament of Osborne
Price, 2004
Diagnosis
• History and physical
• Symptoms usually specific to area of
pathology
• Electroencephalogram (EEG)
• X-ray
• Myelogram
• CAT Scan
• MRI
• Cerebral arteriograms
Medications
• Lidocaine 1% with epinephrine
• Topical hemostatic agents: gelfoam,
avitene, surgicel, bone wax
• Antibiotic irrigants
• Topical papaverine for prevention of spasm
during intracranial artery surgery
• Methyl methacrylate with cranioplasty
• Heparin saline irrigation again with
intracranial artery surgery
• Contrast solutions with cerebral
arteriography
• Gliadel wafers (tumor bed of glioblastoma)
Anesthesia
• General
• Could be local with MAC for minor
laceration suturing
Positioning
• Cranial Surgery
• Supine primarily, with
a specialty headrest
and or fixation devices
• Can be lateral or semilateral
• Sitting
• Prone
• Varies with location of
access
• Spinal surgery
• Anterior procedures
require supine
• Posterior procedures
require prone
Preps
• Will require shave especially on head
• Varies with surgeon preference:
betadine, alcohol, chlorohexidine
• Care taken NOT to get in patient’s
eyes or facial orifices
Draping
• Toweled out
• Adhesive type drape
• Specialty drapes: laparotomy,
thyroid, craniotomy, lumbar
• Stockinette for peripheral
procedures
Supplies
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Marking pen
Disposable bi-polar cord
Monopolar pencil/bovie
Cottonoids/patties
Raney clips
Hemostatic clips
Shunt catheters, tubing, connectors
Cotton balls
Hemovac drain
Nerve stimulator
Telfa
Microscope drape
C-Arm drape
Ultrasound wand drape
Instruments
• Minor tray if laminectomy and
craniotomy trays do not have basic
instrumentation
• Laminectomy tray
• Craniotomy tray
• Basic ortho tray
• Plates and screws
• Specialty self-retaining retractor
trays: Greenburg
Miscellaneous
Instrumentation
• See pages 987-990 in PRice
Equipment
•
•
•
•
•
•
•
•
•
•
•
•
•
•
microscope
Video tower
YAG or CO2 laser
Positioning equipment: Mayfield headrest, Gardner-Wells
Operative Ultrasound machine
Stereotaxis system
CUSA Cavitron ultrasonic aspirator
Bipolar and monopolar ECU
Nitrogen source for power equipment (saws/drills)
Mayfield overbed table
Headlight and light source
C-Arm and monitor
Cell saver
Fluid warming and temperature regulating equipment
Dressings/Drains/Postop Care
• Dressings surgeon preference
• Drains surgeon preference
• Post-op care: keep field sterile until
patient has left the OR
• Careful with moving patient to avoid
patient injury and hemorrhage
Post-operative
Complications
•
•
•
•
•
•
Infection
Hemorrhage
Nerve damage
CSF leakage
Meningitis
Neurological deficits