Epidural injections

Spinal Epidural Injections
A Good Adjuvant in Spine Management
Mohamed Mohi Eldin
Professor of Neurosurgery,
Cairo University, Egypt.

Epidural root of drug
administration

EPIDURAL INJECTIONS
(Painless Outpatient Procedure)
Described by Evans in 1930
Used in LDD for over 80 years
Several studies demonstrated safety and efficacy
Existing agents used include local anesthetics, analgesics,
and steroids.

Epidural root of drug administration
REMAINED stagnant over 25 years,
with no new drugs developed

Some Facts
• 80% of the population experience at least once LBP
• Disc herniation the most frequent cause
• LDP related to mechanical and inflammatory causes.
• The inflammatory causes ( immune response to the
protruded disc material )
– cell-mediated,
– biohumoral factors and
– inflammatory enhancers.

The mechanical causes of LDP
• Direct causes:
– compression of the nerve roots,
– deformation of the ligaments and
annulus,
– stimulation of the nociceptors of
Luschka’s nerve
• Indirect ischaemia due to:
– arterial compression,
– venous stasis

To counteract these mechanical effects,
the unique microstructure of the intervertebral disc
should be understood
• The nucleus pulposus (NP)
– macroscopically cloudy
and jelly-like
– mostly of water,
– collagen and
proteoglycans.
• The annulus fibrosus (AF),
• Similar in composition to the
nucleus,
– less water and greater
collagen.
– In a laminar structure

Spontaneous Regression of Lumbar
Disc Herniation

The Procedure
As most minimally invasive procedures
• Needs a nonhospital, outpatient protocol
• Eliminates the risks of post-operative scarring
• Can also be repeated
• Leaving the anatomical corridors intact
• Wıth a high rate of success ( 50 to 80%) of excellent or good
results
Is justified by the patients:
Discussing the technique make them keen to try
Relatively painless nature of the procedure
No sedatıon before the procedure
Cardiac monitoring is not required
Thus,
causes minimal patient discomfort,
making the procedure ideally suited to outpatient settings.

Insertion Technique.. Lateral Position
Knees toward the
chest
head flexed
forward
anterior flexion of
the vertebral
column.
A pillow is placed
under head to
maintain spinal
alignment.

Insertion Technique.. Sitting Position
The legs hang over the
edge of the bed with
the feet supported.
The shoulders are
�hunched� forward
Patient is encouraged to
hug a pillow in towards
the abdomen (anterior
flexion of the spine).

Insertion Technique.. General Rules
As near as possible to the segmental disease
Expected epidural blockage needs a more
caudal or cranial instillation to prove effective

Insertion Technique.. Site Selection
Adult spinal cord ends at approximately L1,
making the lumbar epidural safer than the
thoracic or cervical placement.

Insertion Technique.. Site Preparation
Skin is typically prepared with:
Povidone iodine solution (Betadine)
(works by contact and does not require scrubbing)
Chlorhexidine
used in the event of an iodine allergy.
Sterile drape
Site should be wiped free of iodine
Gloves changed to prevent introducing iodine into
the epiduralspace.

Insertion Technique.. Epidural Tray
• 25 gauge needle for skin
analgesia
• 4cm, 22 gauge needle for deep
infiltration
• 18 gauge needle for epidural
• Epidural needle (Tuohy,
Crawford)
• Epidural catheter
• 2 ml syringe for infiltration
• 10 ml syringe for loss of
resistance tests
• Normal saline
• Injection Drugs
• Filters and caps for epidural

Insertion Technique.. Needles
Epidural needles larger gauge (16-17) than a
spinal needle to permit better assessment of
loss of resistance and passage of a catheter.

Insertion Technique.. Hand Position
Depth of the ligamentum flavum and orientation of the
interspinous space can be assessed .
The hub of the epidural needle is grasped using its flanges.
Other fingers are braced against back to prevent unintentional
movement.
The needle is advanced through the interspinous ligament until
entry into the ligamentum (3.5-5 cm deep to the skin).

Insertion Technique.. Blind Technique
Inaccurate needle placement in 25-30 %

Blind Technique.. Bromage Grip
Loss of Resistance technique entering ligamentum flavum
Syringe with air, or saline with an air bubble
Needle is advanced by rotation of entire hand while
continuously compressing the syringe with a �bouncing�
movement �

Loss of Resistance
When a �loss of resistance occurs, air or saline is
injected without resistance being felt.

Failure of blinded epidural infiltration
Technical difficulties
Scoliosis
Failed back syndrome

Insertion Technique.. Fluoroscopy Guided
• Persistant radicular pain in disc
herniation & spinal canal stenosis

Fluoroscopically guided interlaminar
cervical epidural injections

Injected Drugs.. Local Anaesthesia
Primary anesthetic
Bupivacaine, Chloroprocaine, Etidocaine, Lidocaine,
Mepivacaine, Ropivacaine
Supplementation of GA
Opioids, Fentanyl 5-100mcq, Morphine 2-20 mg
Analgesia
Only preservative free LA; or agents labeled clearly for
epidural use
Adjuncts
Epinephrine 1:200,000 (5mcq/ml)
Prolong duration of the block, Decrease bleeding, Decrease
toxicity

Injected Drugs.. Steroids
Betamethasone (Long-acting)
Dexamethasone (Long-acting)
Methylprednisolone (Intermediate-acting)
Prednisolone (Intermediate-acting)
Triamcinolone (Intermediate-acting)
Hydrocortisone (Short-acting)

Injected Drugs.. Others
Mannitol
Mitomycin-C
Hyaluronidase
Magnesium Sulfate

Insertion Route.. Interlaminar
Midline
Paramedian

Can be performed at all levels of the spine
Involve needle passage through ligamentum flavum

Advantages include
Increased chance of drugs to reach adjacent levels,
Ability to treat bilateral pain,
Need for a lower volume of medication when compared
with caudal injections.

Disadvantages include
Potential for dural puncture
Deposition of drugs into the dorsal epidural space,
(more distant from the site of pathology)
Although 100% incidence of ventral epidural flow

In light of the increased risk for complications
stemming from TF ESI performed in the upper
lumbar, thoracic, or cervical regions, IL ESI
should always be the first-line injection treatment
in these areas.

Interlaminar Route.. Lumbar
A midline or paraspinous / paramedian
approach may be used
•

Interlaminar Route.. Dorsal
Needle inserted one fingerbreadth lateral to the interspace
Needle is inserted perpendicular to the skin until the lamina
is met
Needle is angled 45 degrees medially and 45 degrees cephelad
and walked to the ligamentum flavum
Loss of resistance is then used to enter epidural space

Interlaminar Route.. Cervical
Cervical ESIs are effective in short term
Evidence is stronger for herniated disc and soft
central stenosis than it is for foraminal or osseous
stenosis
ESI should not be a first-line treatment.

Insertion Route.. Caudal
The sacral hiatus provides the most caudal
and direct route of entry to the epidural
space for the administration of drugs for the
treatment of lumbar pathology.

Sacral Canal.. Contents
Terminal part of the dural sac, ending between S1 and S3.
Five sacral nerves and coccygeal nerves (the cauda equina).
Sacral epidural veins ending at S4, but may extend throughout
the canal. They are at risk from catheter or needle puncture.
Filum terminale - which does not contain nerves. This exits
through the sacral hiatus and is attached to the back of the
coccyx.
Epidural fat, changes from a loose texture in children to a
more fibrous close-meshed texture in adults.

Caudal Route.. Positioning
In an adult, the distance from the tip of the coccyx to the
sacral hiatus is approximately the same as the distance
from the tip of the index finger to the proximal inter-
phalangeal joint.

Caudal Route.. Preparation
A bleb of local anesthetic is raised in the skin overlying
the sacral hiatus, between the sacral cornua.
Note: The procedure must be carried out with a strict
aseptic technique. The skin should be thoroughly
prepared and sterile gloves worn. Any infection in the
caudal space is extremely serious.

Caudal Route.. Technique
A 22 gauge short beveled cannula or needle is
directed at about 45� to skin
inserted till a "click" is felt as the sacro-coccygeal
ligament is pierced (1). The needle is then carefully
directed in a cephalad direction at an angle
approaching the long axis of the spinal canal (2).

Aspirate, looking for CSF or blood.
Followed by injection of a 3ml test dose of local
anesthetic, with a hand positioned over the
sacrum to detect any tissue swelling resulting
from malposition of the needle or catheter
either subperiosteally or along the dorsal
surface of the sacrum.
In the absence of pain on injection, the definitive
dose may be injected slowly in small, repeated
doses.

After negative aspiration, contrast is injected under
fluoroscopy into the epidural space, followed by
the injectate solution
If CSF is aspirated or if blood continues to be
aspirated after repositioning of the needle or
catheter, the block should be abandoned.

Caudal catheter-guided approach
Insert a catheter, can be guided up to the
targeted area of pathology.
Epidural lysis of adhesions

Which is more effective ?
Transforaminal ESI is superior to interlaminar or
caudal ESI
( Drugs administered closer to the area of pathology)
Trials found a higher proportion of positive results in
caudal ESIs than interlaminar ESIs
(injection of higher volumes of solution)

Selection of a particular ESI
technique ?
The rationale for is guided by
multiple factors to include
radiological evidence of pathology,
patient symptoms,
previous surgery,
demonstrated efficacy, and
consideration of possible complications.

EFFECT OF REGION
For cervical ESI, a best-evidence found support for
short-term improvement of radicular symptoms,
Few clinical trial evaluating thoracic ESI found no
significant difference between epidural steroids
and epidural local anesthetic through 12-month
follow-up.
Lumbar ESI report positive findings, from fair to
good evidence, level 1 evidence, level II-1 and II-2
evidence and moderate evidence.

EFFECT OF DOSE AND
INJECTATE
Both the dose and volume vary depending on the route of
injection, with amounts increasing as TF, IL, and caudal
ESI are performed, respectively.
IL dose of 40 mg of methylprednisolone provided a similar
reduction in pain compared with 80 mg.
The use of higher volumes may result in better pain relief.
(Steroid injected in a volume of 40 mL of saline provided
superior pain relief than when the same dose of steroid
was injected by itself at 18 months’ follow-up).

EFFECT OF TYPE OF STEROID
Depot steroids is statistically better than
nondepo-steroids
(conflicting evidence)

EFFECT OF UNDERLYING
PATHOLOGY
LDP represents the most commonly improved with
ESI, particularly for short-term relief of pain.
For intermediate- and long-term benefit, the
benefit is smaller
Spinal stenosis has less benefit than for LDP,
but greater than that for failed back surgery
syndrome and axial back pain.
In cervical ESI, central stenosis experienced greater
benefit than foraminal stenosis, or nerve root
compression.

IDEAL NUMBER OF
INJECTIONS ?
No evidence to support the practice of a routine series of
injections. However, the strategic use of repeat injections
may enhance outcomes in certain contexts.
The guidelines published by the American Academy of
Physical Medicine and Rehabilitation and ISIS state that
if additional injections are warranted, they should be
separated by at least a 2-week interval to enable assessment
of the full response and to minimize adverse effects such as
adrenal suppression.

Complications
• Reported early in our experience.
• No major complications
• No local or epidural infections
• No other delayed complications
• Minor complications in all groups were
– Transient hypotension and vomiting in 2 cases (3.3%),
– Flushing in 6 cases (10%)
– Headache without any CSF leak in5 cases (8.3%)
– Transient sensation of chest compression in five cases (8.3%).
• Significant transient hypotensive episode reported in 1 patient,
recovered few minutes later.
• Vomiting with a severe vasovagal response due to rapid injection, in
the sitting position, in 1 patient. She was observed for 3 hours in the
emergency department, with no residual complications. Her back
pain was nevertheless dramatically relieved by the procedure.

Intravascular uptake during fluoroscopically
guided cervical interlaminar injection at C6-7:

The Procedure
• No Local anesthetic
• 18-gauge Tuohy needle
• Puncture 2 to 3 cm caudal to point of entry
• An interlaminar technique at L3, L4, or L5
• The primary target was at the L4–L5 level
• 10–20 ml separately injected per injection
• Patient are kept in bed, for at least 2 hours
post-injection
• change position every ten minutes after
injection
• Absolute bed rest for a week after.

Drug cocktail
Theory
Addition of osmotic, anti-adhesive media to
anti-edema, anti-inflammatory media
Proved to have a good chance of
decreasing the volume of the prolapsed disc

Definite Volume Change
Volume change is reflected on the disc bulge
& the tension put on the stretched annulus

Volume change is reflected on the disc bulge
& cross-diameter of the spinal canal

Specially effective in HIZs,
both clinically & radiologically.

HIZ reduction is reflected on the cross-
diameter of the spinal canal

HIZ reduction is reflected on the cross-diameter of the
spinal canal & on the posterior longitudinal ligament

Volume reduction is reflected on the posterior
longitudinal ligament

With posterior longitudinal ligament
relaxation

Bulge reduction with relaxation of
longitudinal ligament

A small change in volume produces large
change in pressure and later allows
healing of the annular cracks

A small change in volume produces large change in
pressure and marked clinical improvements

May be Minimal, but clinically effective,
especially in lateral recess disc bulges

May be Moderate, but clinically effective

A moderate change in volume may still produces
moderate clinical improvements,
according to the type and shape of the bulge

May be Moderate, but clinically ineffective
Specially in mixed disc types

May be Maximum,
and clinically
effective

May be Maximum, and clinically
effective

• A nonhospital,
outpatient protocol
• No post-operative
scarring
• Can also be repeated
• Anatomical corridors
intact
• High rate of success (
50 to 70%) of excellent
or good results
Virtual Catheter Discectomy

Access Failures
Wet spinal tap precluded access
Another higher catheter insertion was done,
without any subsequent drug instillation for
24 hours
Catheter obstruction
necessitates another catheter insertion
Accidental catheter extrusion
another catheter has to be inserted
Failure of access the interlaminar gap

• Wet spinal tap
• Catheter obstruction
• Accidental catheter
extrusion
• Failure of access the
interlaminar gap
Access Failure

Steroid injection of the cervical spine
Complications
Tetraplegia
(related to arterial injection of corticosteroid into a
radiculomedullary artery with subsequent occlusion)
Cerebellar infarction
(intra-vascular injection of particulate steroid resulting in
embolic occlusion through the vertebral artery with
subsequent infarction)
Epidural hematoma
(Puncturing of the epidural venous plexus)

To avoid risk of major complications
Injection of Altim® foraminal infiltration
(Hydrocortancyl: direct toxicity on vascular
structures).
Needle: > 22G.
Anatomy (injection of contrast ): +++
Avoid the epidural scar tissue.

Finally
before undergoing a selective steroid
injection of the lumbar spine
Patients should be warned of
the risk of paraplegia in operated-on
patients.

Epidural injections

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