Transcript myelography - El Camino College

MYELOGRAPHY
and
CNS Exams using MRI & CT
Spring 2012
Meninges

Membranes that enclose the brain
and spinal cord

Dura Mater- outer layer

Arachnoid = middle layer

Pia mater = innermost layer

Subarachnoid space = wide
space between arachnoid and
pia mater
Subarachnoid space

Wide space between arachnoid and pia mater
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Filled with CSF
Bathes brain & spinal cord with nutrients
Cushions against shocks and blows
Where contrast is injected for myelograms
CSF Information
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Total adult CSF volume is 150 ml
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50% intracranial
50% spinal
Adult opening pressure is normally 7-15 cm
fluid
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>18 abnormal
Young adults slightly higher <18-20
Spinal Cord Diameter
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AP diameter is 7mm through C7
C7 to conus medullaris is 6mm
At conus it is 7mm
Cord size is considered abnormal if it is over
8mm or under 6mm
Myelography

General term applied to the radiologic examination of
the CNS structures situated in the vertebral canal
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Requires contrast introduction into the subarachnoid
space by spinal puncture
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Puncture made at L2-L3 or L3-L4 space
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May also be introduced into cisterna magna at C1 and
occipital bone
Myelography

Contrast is generally
water-soluble,
nonionic, iodinated
medium
OMNIPAQUE
http://www.ismp.org/newsletters/acutecare/artic
les/20031127.asp
ISOVUE
Contrast Precautions

Verify it is the correct contrast
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Non-ionic iodinated contrast
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Omnipaque or Isovue
Correct concentration

180 and 300 common

Check expiration date

Keep contrast vial in room until procedure is
complete
Puncture made at L2-L3 or L3-L4
space and Cisterna Magna
Spinal needle injection
MYELOGRAM WITH CONTRAST
Room should be prepared by RT
before patient arrival
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Table and equipment cleaned
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Footboard and shoulder
supports attached
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Radiographic equipment
checked

Image intensifier locked to
prevent accidental contact
with sterile field or spinal
needle
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Tray setup
FOOT
BOARD
SHOULDER
PADS
Hand grips
MYELOGRAM TRAY
Additional items
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Blankets
Sterile towels
Sodium bicarbonate (if not in tray)
Non-ionic iodinated contrast media
Sterile gloves for DR
Shields for PT, DR, anyone else in room, and
yourself
Varying sizes of spinal needles and needles
Extra syringes and tubing
Cleaning liquid
Syringes and Spinal Needles
Syringes
Spinal
Needles
(covered)
More Spinal Needles (uncovered)
PRE- Procedure :Myelography
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Premedication rarely needed
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Patient should be well hydrated
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Check orders, obtain history, labs results (if necessary),
and previous exams
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Informed consent:
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Risks, benefits alternatives
Procedural details, including table movement and
sensations should be explained, and get pt into a gown
Contraindications and Considerations
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PT < 15.0 seconds
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Platelets >100,000
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If below 50,000 a platelet transfusion may be indicated
before procedure
Heparin stopped 4 hours before
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Preferable to reschedule exam if below 15
Can be restarted 2 hrs after procedure
Usually given as IP
Coumadin stopped 3-4 days before
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Usually OP
Labs usually indicated
Radiation Safety
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Have shields for PT’s, DR and yourself
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Question LMP and the possibility of being pregnant
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Use cardinal rules
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Time
Distance
Shielding
ALARA
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Use pulse if possible
Save the last image on screen when possible
Prone &
Lateral Flexion
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Prone
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Pillow under abdomen
for flexion of spine
Lateral flexion is not
commonly used
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Widens interspace for
easier introduction of
needle
Scout Images
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Cross table lateral
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With grid
Closely collimated
Myelography
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Local anesthesia given at puncture
site
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Lidocaine and sodium bicarbonate
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Spinal needle inserted (pressure
obtained)
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CSF usually withdrawn and sent to
laboratory
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Contrast injected and needle
removed
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9-12 ml
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Table angle and gravity used to
move contrast under fluoroscopy
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Spot images taken as needed
Spot Films
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Central ray vertical or horizontal using CR or film
screen cassettes
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Images are taken at
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Site of blockage
Level of distortion
If conus medullaris is area of concern:
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Lay pt supine
Central ray at T12- L1
Use 10x12 cassette and collimate tightly
Myelogram overview
Myelography
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If contrast is moved into cervical area, head is
positioned in acute extension to prevent
contrast from entering ventricular system
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Acute extension compresses cisterna magna and
is the only position that will prevent contrast from
entering ventricles
Myelography
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Usually performed as outpatient basis
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Common for CT myelography (CTM) to be used with
conventional Myelogram
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MRI often used instead
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Myelography and CTM still used for patients with
contraindications for MRI
 Pacemakers and metal fusion rods
Post procedure: Myelography
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Monitoring required
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Head and shoulders elevated 30 to 45 degrees
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Bed rest for several hours
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Fluid encouraged
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Puncture site checked before release
Possible Complications from
Myelography
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Vomiting
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Spinal Headache
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Due to loss of CSF
during puncture
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Increased severity
upright
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Decreased pain when
recumbent.
Vertigo
Neck Pain
More Severe Complications
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Nerve root damage
Meningitis
Epidural abscess
Contrast reaction (anaphylactic shock)
CSF leak
Hemorrhage
Treatment for Spinal Headache
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Initial treatment
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Persistent headache
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Tylenol
If a fever occurs,
contact MD
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Horizontal position
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Forced fluids
Beyond 48 hrs w/o
fever (24 hrs if severe)
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May be indicative of
meningitis
Caffeine
Blood patch
Blood Patch
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Sterily injecting a small
amount of patient’s
blood into the epidural
space
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Clot will occur over
hole
Usually will stop
headache immediately
1st patch is 70%
effective
2nd patch is 95%
effective
Myelogram radiographs
Myelograms Images
CTM
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Performed after intrathecal injection
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Can be performed at any level of vertebral column
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Multiple slices taken (1.5 – 3mm)
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Gantry is tilted
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Windowing allows for density and contrast changes
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Can obtain images with small amounts of contrast
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Can be done 4 hours after initial injection
CTM
MRI of Spinal Cord and CSF flow
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Non-invasive
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Provides anatomic detail of brain, spinal cord,
intravertebral disc spaces, and CSF within
subarachnoid space
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Does not require intrathecal injection
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Does not have bone artifacts
MRI basics
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T1 & T2 images can be taken
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Head coil for brain
Body coil and surface coil form spine
IV contrast can be used to enhance tumor
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Gadolinium
Contraindications to MRI
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Pacemakers
Ferromagnetic aneurysm clips
Metallic spinal fusion rods
Myelography Using MRI and
Conventional methods
MYELOGRAM
Preference of MRI
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MRI is the preferred modality for middle and
posterior cranial fossa of brain.
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In CT these structures are obscured by bone
artifacts
Spinal cord
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Allows direct visualization of spinal cord, nerve
roots, and surrounding CSF
Can be done in various planes
Aid in diagnosis and treatment of neurodisorders
Usefulness of MRI
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Assessing
demyelinating disease
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Such as MS
Spinal cord
compression
Postradiation therapy
changes of spinal cord
tumors
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Herniated disks
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Congenital
abnormalities of
vertebral column
Metastatic disease
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Paraspinal masses
MRI and Brain imaging
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Middle and posterior fossa abnormalities
Acoustic neuromas
Pituitary Tumors
Primary and metastatic neoplasms
Hydrocephalus
AVM’s
Brain atrophy
Not valuable for diagnosing:
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Osseous bone abnormalities of skull
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Intracerebral hematomas
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Subarachnoid Hemorrhage
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CT preferred for these 3 illnesses
CT of Brain basics
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Useful for demonstrating size, location and
configuration of mass lesions and surrounding
edema
Assessing cerebral ventricle or cortical sulcus
enlargement
Shifting of midline structures caused by mass
lesions, cerebral edema, or hematoma
Indications for Pre and Post contrast
Imaging using CT
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Suspected Neoplasms
Suspected metastatic disease
Arteriovenous malformation (AVM)
Demyelinating disease (MS)
Seizure disorder
Bilateral isodense hematomas
Indications for Brain scans without
Contrast media
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Dementia
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Craniocerebral trauma
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Hydrocephalus
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Acute infarcts
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Post evacuation follow up of hematomas
CT Brain imaging
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Most often Axial orientation
Gantry 20-25 degrees to OML
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Allows lowest slice to provide an image of both the upper
cervical, foramen magnum, and roof of orbit
12-14 slices
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8-10 mm slices
3-5 mm slices through post fossa
Depending of PT size
Slice thickness
CT Brain imaging (cont)
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Coronal imaging
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Helpful in evaluation of
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Pituitary gland
Sella turcica
Facial bones
Sinuses
CT: Modality of choice
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Modality of choice for
the following”
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Hematomas
Suspected aneurysms
Ischemic or
hemorrhagic strokes
Acute infarcts
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Used as initial
diagnostic modality
for:
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Craniocerebral trauma
CT of Spine
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Useful in diagnosis of vertebral column
hemangiomas and lumbar spine stenosis
Often used post-trauma to assess Axis and
Atlas fractures and for better demonstration of
C7-T1
Clearly demonstrates size, number and
locations of fracture fragments of C, T and L
spine.
Surgery Applications of CT imaging
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Greatly assists surgeons in distinguishing
neural compression by soft tissue from
compression by bone
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Post-op
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Useful in assessing outcome of surgical
procedure
MRI vs. CT
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MRi superior to CT for imaging of posterior
fossa
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CT has artifacts from bone
MRI is free from bone artifacts
MRI has inability to image calcified
structures. CT is superior for calcifications
MRI can detect cerebral infarction earlier than
CT.
Both modalities provide similar information
on subacute and chronic strokes
Diskography and Nucleography
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Radiologic exam of individual intervertebral
disks
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Small amount of water soluble iodinated contrast
injected into center of disk double needle entry
Pt’s given local anesthetic
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Used to investigate disk lesions
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So pt is alert and communicate with DR about pain
when needle and contrast are inserted
Ruptured nucleus pulpous
Has been largely replaced by CTM and MRI
Diskograms
Lumbar Diskograms
Vertebroplasty
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Interventional radiology procedure to treat
compression fractures or other pathologies in
the vertebral bodies
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Used when conservative treatment does not
work
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Used when severe pain does not improve over
a number of weeks of treatment
Percutaneous Vertebroplasty
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Done in specials or OR
Trocar needle is advanced through pedicle into the
vertebral body under fluoro
Non-ionic contrast media is used to confirm needle
placement
Bone cement ( polymethyl methacrylate) is injected
into vertebral body using fluoro
AP & LAT images taken post procedure
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CT sometimes done as well
Vertebroplasty under Fluoro
Post Vertebroplasty
Percutaneous Kyphoplasty
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Trocar needle advanced
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Through pedicle, avoiding spinal canal
Biopsies can be taken
Balloon catheter used to expand the compressed
vertebral body to near its original height before
injection of bone cement
Trocar needle is considered the “working
cannula”
Kyphoplasty Outline
Pre and Post Kyphoplasty radiographs
Complications of Vertebroplasty and
Kyphoplasty
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Most common: leakage of cement
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Less common: pulmonary embolism
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Death
Success of Vertebroplasty and
Kyphoplasty
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Success is measured by the pt’s pain
reduction and quality of life improvement
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Can help reduce hunchback and restore
normal curvature
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With Kyphoplasty there is a 80-90% success
rate
Pain Management
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Epidural Injection
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Facet Injection
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Spinal Cord stimulation
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Radiofrequency Neurolysis
Considerations of Pain Management
Interventional Procedures
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Stop NSAID 3 days prior to procedures
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With Facet injections no pain relievers 4
hours prior to procedure
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Takes 3- 10 days for full results to manifest
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Done when conventional treatment has not
helped
Epidural
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Used to treat pain as a result of and injured disk affecting
spinal nerves
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Done under fluoroscopy with PT awake
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Decreased inflammation & swelling
Takes 10- 15 minutes
Recovery short
Sterile procedure
Complications
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Spinal headache (most common)
Infection
Epidural Hematoma
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Can be done at any
level of the spine
Place a needle (often
with catheter) into
epidural space
Small amount of
contrast injected to
verify placement
Corticosteroid &
anesthetic injected (
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Cortisone
Lidocaine
Epidural
Epidural
with Catheters
Facet Injections
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Indications:
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Diagnosis
Therapy
Causes of pain include:
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Inflammation, swelling,
or arthritis
Awake under fluoro
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Takes 20-40 minutes
Sterile procedure
Complications
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Pain at site
Bleeding
Infection
Increase in pain
Facet Injections
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Inject needle into facet
joint
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Inject contrast to verify
needle placement
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Inject lidocaine or
bupivivaine
(anesthetic) &
corticsteroid (antiinflammatory)
Side effects of Steroids
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Fluid retention
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Weight gain
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Mood swings
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Increase in blood pressure
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Usually temporary
Spinal Cord Stimulation
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Delivers low voltage electrical stimulation to
the spinal cord
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Delivered through 1-2 wires which are carefully
placed in epidural space
Electrical signals replace sensation of pain with a
tingling sensation
Done in two stages
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Trial
Permanent placement
SCS Radiographs
Trial and Permanent Placement
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Done in OR
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If trial period helps
permanent generator is
placed under skin in OR
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Contains generator with
battery (some are
rechargeable)
Local anesthetic &
intravenous sedation

Wires placed in epidural
space
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PT goes home with wires
in place for 1 week to test
and see if it helps

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Periodically battery is
replaced
Others have transmitters &
generators
Generators only vs.
Generators with Transmitters
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SCS with generators
inside the body must be
replaced in OR
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Some are one time use
Those that are
rechargeable allow for
more time in between
battery replacement

SCS with transmitters
can also be one time
use or rechargeable

PT can adjust settings
according to different
programs

Set by DR according to
PT’s pain patterns
SCS With Generator and Transmitter
SCS Indications, Benefits & Risks
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Indications:
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Chronic pain associated
with:

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Neuropathic pain
Failed back surgery
syndrome
Arachnoiditis
Certain vascular disease
Benefits
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Reduces rather than
eliminates pain
Reduces pain by 50%
Reduces narcotic use
Risks
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Infection & bleeding
Paint at insertion site
Nerve injury
Dural puncture or tear
Migration or breakage of
wire
Radiofrequency Neurolysis
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Uses high frequency radio waves to produce a
heat lesion
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Lesion ablates or inactivates nerves responsible
for transmitting pain
Usually done in L and C spine
Pain can be caused from whiplash or arthritis
Done under fluoro in OR
Radiofrequency Neurolysis

Helps for 6-24 months

70% of PT’s get relief

Takes about 45-60
minutes

Can be repeated if pain
returns
Radiofrequency Neurolysis
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PT is awake and mildly sedated
Local anesthetic injected

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Stimulation test is done to verify needle placement
PT is questioned for tingling or buzzing feeling (as
when hitting your funny bone)
Once PT confirms this , they are sedated more
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Radio waves are transmitted ablating the nerve
Muscles may spasm or “jump”
RF Risks
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Infection
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Bleeding Blood vessel damage
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Soreness for a few days