NeurosurgeryNeurosurgery

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

• Motor nervous system• 2 parts:1. Somatic Nervous System• Skeletal muscle control• Conscious control2. 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

• Meninges • Between vertebra & spinal cord• Epidural space between vertebra and dura

mater1. Dura Mater outermost layer extends to S-2• Subdural space between dura mater and

arachnoid 2. Arachnoid extends to S-2• Subarachnoid space contains CSF3. 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 NervesI. Olfactory - sense of smellII. Optic – sense of sight/visionIII. Occulomotor – eyeball, eyelid movement (medial,

inferior, superior rectus, inferior oblique), pupil constriction, lens accommodation

Muscle sense for eyeballIV. Trochlear – eyeball movement (superior oblique) Muscle sense for eyeballV. 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

VI. Abducens - same as IV eyeball movement (lateral rectus) and eyeball muscle sense

FYI: EOM formula LR6(SO4)3

Cranial NervesVII. 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” Price, 2004

• Malignant tumors:• “Astrocytes or gliomas” 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” Price, 2004

• Hydrocephalus result of obstructed CSF flow

• Spina bifida

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 semi-lateral

• 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/Post-op 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