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NEUROSURGERY
Nervous System
Senses changes in environment, interprets them, stimulates response/movement
 CNS central nervous system: brain and spinal cord
 PNS peripheral nervous system: everything else
 Afferent nervous system: sensory neurons take info from PNS to CNS
 Efferent nervous system: motor neurons take info from CNS to PNS
 Somatic nervous system: skeletal muscle, conscious control
 Autonomic nervous system: cardiac m, smooth m, glands; uncons control
 Sympathetic div = increased skeletal blood flow, decreased organ
blood flow ; also called fight or flight
 Parasympathetic div = decr skeletal blood flow, incr organ blood flow
 Both are controlled by hypothalmus and medulla oblongata, go to the
same effector or target, are antagonistic
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Spinal cord transmits info to/from brain, integrates reflexes
 Begins at foramen magnum and extends to 2nd lumbar; 16-18” in length
 Vertebrae: 7 cervical, 12 thoracic, 5 lumbar; 5 fused [sacrum], 4 fused [coccyx]
 Intervertebral disks: separate vertebrae, bear/cushion stress on vertebrae
 Outer layer is tough and called the annulus fibrosis
 Inner core is soft and called the nucleus pulposus
 Meninges : membranes between vertebrae & 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 mater extends to S-2
 Subarachnoid space contains CSF
 Pia mater adheres directly to spinal cord and extends to L-2
 Spinal nerves -- 31 pairs: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
 Names and numbers depend on where enter and exit
 Each has a ventral [motor] and dorsal [sensory] root
Brain: weighs approx 3 lb., protected by the cranium or skull
 Brain stem
 Medulla oblongata: lowest part, 5 of 12 cranial nerves
 Pyramids: 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
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 Midbrain or mesencephalon: above pons
 Involuntary eye and head movement in response to auditory stimuli
Diencephalon
 Thalamus
 Relay center for sensory information
 Interprets stimuli for example pain from changes in temperature (hot stove);
recognizes crude touch NOT localized touch
 1st level of reasoning occurs here
 Hypothalamus
 Controls large number of subconscious functions
 Controls most of autonomic nervous system
 Is 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, see p 970, fig 24-4
Motor/sensory/association areas, associated with specific lobes
 Frontal: memory, abstract thinking, ethics, judgement, emotion, expressive
speech, motor
 Parietal: sensory, receptive speech, written word
 Temporal: auditory, olfactory
 Occipital: visual cortex, visual association
Limbic system: controls emotion/functions in cerebral cortex and diencephalon
Meninges: continuous layer with spinal cord, but NO epidural space
Cerebrospinal fluid (CSF): shock absorber and circulates nutrients
 About 800ml/day produced by the choroid plexus, a specialized set of capillaries
 Circulates in subarachnoid space, central canal [spinal cord], ventricles [brain]
 Reabsorbed in arachnoid villus found in the parietal lobe
Blood brain barrier
 Specialized capillaries exclusive to the CNS, least permeable in the body
 Advantage = keeps out unwanted chemicals
 Disadvantage = poor diffusion makes it difficult to treat conditions such as
encephalitis
Cranial nerves: direct from brain, do not go thru spinal cord
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All originate in the brain stem EXCEPT the 1st and 2nd
 Classified as sensory or mixed (sensory and motor) nerves
 Identified by Roman numerals and names
 Olfactory - sense of smell
 Optic – sense of sight/vision
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Occulomotor – movement of eyeball[medial, inferior, superior rectus, inferior
oblique], eyelid, pupil, lens [ciliary m]; muscle sense for eyeball
 Trochlear – eyeball movement (superior oblique); muscle sense for eyeball
 Trigeminal
 Motor: masseter muscle control
 Sensory (convey touch, pain, temp changes)
 ophthalmic (forehead to corner of eye),
 maxillary (corner of eye to upper lip/teeth)
 mandibular (lower lip/teeth/tongue)
 Abducens - eyeball movement (lateral rectus); eyeball muscle sense
FYI: EOM formula LR6(SO4)3
 Facial- facial muscles; lacrimal, salivary glands; anterior 2/3 of tongue (taste)
 Vestibulocochlear - vestibular [balance]; cochlear [hearing]
 Glossopharyngeal -salivary gland secretion and posterior 1/3 of tongue
 Vagus – internal organ control motor and sensory; originates in medulla and
goes down through neck into chest and abdomen
 Accessory – head and neck movement, speech, and muscle sense for the head
 Hypoglossal – tongue muscles: swallowing, speech, muscle sense for tongue
Neuropathology
 Cervical spine: can have severe consequences due to all spinal nerves pass thru it.
Treatment is conservative, with minimal surgical intervention.
 Spondylosis: is osteophyte or bone spur formation in the spinal canal
 Cervical disk extrusion: acute or chronic
 Thoracic spine
 Spondylosis
 Extrusion of disk
 Lumbar spine
 Spondylosis
 Stenosis
 Spondylolithesis
 Disk extrusion
 Neoplasms/Tumors
 Primary originate in nervous tissue or meninges
 Secondary are metastasized from other parts of the body
 Benign tumors: craniopharyngiomas, epidermoids, hemangiomas, menigiomas,
acoustic neuromas, pituitary microadenomas; usually excisable via craniotomy
 Malignant tumors: astrocytes or gliomas; usually cannot be completely removed
but efforts are made to remove most
 Head Trauma
 Scalp lacerations, fractures, hematomas (epidural or subdural), and brain injuries
 Spinal Cord Trauma
 Vertebral fracture
 Vertebral dislocation
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 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
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
Peripheral nerve pathology
 Carpal tunnel syndrome - compression of the median nerve
 Ulnar nerve compression – compression of ulnar nerve by the ligament of
Osborne
 Diagnosis
 History and physical
Myelogram
 Symptoms usually specific to area of pathology
CAT Scan
 Electroencephalogram (EEG)
X-ray
 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 or could be local with MAC for minor laceration suturing
 Positioning
 Cranial surgery: supine primarily, with a specialty headrest and or fixation
devices, but varies w/ need for access, can be lateral or semi-lateral, sitting, prone
 Spinal surgery: supine for anterior procedure, prone for posterior
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 Specialty equip: Mayfield headrest, Gardner-Wells tongs
Preps will require shave esp. on head; surg pref; do not get in eyes/facial orifices
Draping: towels; adhesive drape; laparotomy, thyroid, craniotomy, lumbar;
stockinette for peripheral proc.
Supplies:
 Marking pen
Hemostatic clips
 Disposable bi-polar cord
Shunt catheters, tubing, connectors
 Monopolar pencil/bovie
Cotton balls
 Cottonoids/patties
Hemovac drain
 Raney clips
Nerve stimulator
 Telfa
Microscope drape
 C-Arm drape
Ultrasound wand drape
Instruments see p 987-990
 Minor tray if laminectomy / craniotomy trays do not incl basic instrumentation
 Laminectomy tray
 Craniotomy tray
 Basic ortho tray
 Plates and screws
 Specialty self-retaining retractor trays: Greenburg
 Miscellaneous Instrumentation
Equipment
 Operative Ultrasound machine
Video tower
 CUSA Cavitron ultrasonic aspirator
Microscope
 Bipolar and monopolar ECU
Stereotaxis system
 Nitrogen source for power equipment (saws/drills)
YAG or CO2 laser
 Headlight and light source
C-Arm and monitor
 Fluid warming and temperature regulating equipment
Cell saver
 Mayfield overbed table
Dressings/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
 Procedures begin on page 992-1021 in Price
 Carpal Tunnel Release
Craniotomy
 Hematoma
Aneurysm repair
 Tumor excision
Cervical Discectomy
 Lumbar Discectomy
Ventroperitoneal Shunt
(VP Shunt)