Chapter 44 Interlaminar Epidural Steroid Injections for Lumbosacral Radicular Pain

Question 1

Most back pain seen in the primary care setting is largely due to

Answer 1

muscular and ligamentous strain and spasm.

Question 2

Back pain may arise from the facet joint and the paraspinal muscles in the dorsal compartment, which is innervated by

Answer 2

the medial and lateral branches of the dorsal rami.

Question 3

Back pain may also arise from the anterior and posterior longitudinal ligaments and the annulus of the disc in the ventral compartment, which
is innervated by

Answer 3

the sympathetic chain and the sinuvertebral nerves.

Question 4

An annular tear may lead to

Answer 4

continued leakage of

nucleus pulposus material and associated chronic inflammation and altered central processing.

Question 5

Radicular pain results from

Answer 5

chemical irritation and inflammation of the

nerve root, which may be swollen and edematous.

Question 6

Disc herniation (HNP)
results in

Answer 6

release of large amounts of phospholipase A2
(PLA2), which favors production of prostaglandins and leukotrienes from cell membrane phospholipids, and resultant inflammation, sensitization of nerve endings, and pain generation.

Question 7

External pressure on

nerve roots by bone can result in

Answer 7

venous obstruction, neural

edema and eventual fibrosis of the nerve and surrounding tissues.

Question 8

Degenerative disc

disease and tears of the annulus fibrosus may result in

Answer 8

leakage of this enzyme from the nucleus pulposus, producing chemical irritation of the nerve roots.

Question 9

The primary indication for steroid injections (ESIs)

Answer 9

radicular pain due to nerve rootinflammation, irritation, and edema.

Question 10

The most well-studied steroids used in ESIs are

Answer 10

methylprednisolone acetate and triamcinolone diacetate. The concentration of both is typically 40 to 80 mg/ml; the most common therapeutic dose range is 40 to 80 mg.

Question 11

Steroid drugs are often diluted with

Answer 11

normal saline or local anesthetic with equivalent results. The volume of injectate varies greatly with the site of injection

Question 12

How much volume is injected into the lumbosacral

epidural space?

Answer 12

The injection of 3 to 5 ml has been used in the lumbosacral epidural space. These volumes bathe both the injured
nerve root that is adjacent to the disc pathology and
additional nearby roots that are also inflamed

Question 13

How much volume is injected into the cervical

epidural space?

Answer 13

In the less capacitant cervical space, 2 to
4 ml should be adequate to bathe the cervical roots at
several levels.

Question 14

How much volume is injected into the caudal

epidural space?

Answer 14

When the caudal route is selected, a larger volume (approximately 10–15 ml) is used to ensure adequate spread of injectate to the midlumbar level.

Question 15

MECHANISM OF ACTION of steroids

Answer 15

Steroids induce synthesis of a PLA2 inhibitor, preventing release of substrate for prostaglandin synthesis. Steroids may also decrease back pain due to inflammation and sensitization of nerve fibers in the posterior longitudinal ligament and annulus fibrosus. steroids
also block nociceptive input.

Question 16

Response to ESI was predicted by

Answer 16

nerve root irritation, recent onset of symptoms, and the absence of psychopathology

Question 17

Indications of ESI

Answer 17

ESI was therapeutic for patients with herniated disc and either nerve root irritation or compression. These latter two factors
were also associated with efficacy in patients with
spondylolisthesis or scoliosis. efficacy
for patients with radicular pain syndromes or herniated nucleus pulposus.

Question 18

five most

important factors influencing the outcome of ESI

Answer 18

accuracy of the diagnosis of nerve root inflammation,
shorter duration of symptoms, no history of previous surgery, younger age of the patient, and location of the needle at the level of pathology

Question 19

four selection criteria for ESI:

Answer 19

an intention to produce short-term pain relief during physical therapy/
rehabilitation; evidence of nerve root involvement; unfavorable response to 4 weeks of conservative therapy; and no contraindications to injection.

Question 20

Patients with radicular

pain should fit into one of these categories:

Answer 20

sensory signs and symptoms of radiculopathy, disc herniation, tumor infiltration of nerve root, postural back pain with radicular symptoms, or acute back pain and radicular symptoms superimposed on more chronic back pain

Question 21

EFFICACY OF ESI

Answer 21

effective in acute lumbosacral radiculopathy.

Question 22

selection of patients

for cervical ESI by the

Answer 22

presence of radicular pain and either physical or radiologic findings corresponding to the painful nerve root

Question 23

use of fluoroscopy would

decrease technical failures with ESI up to

Answer 23

50% to 60%

Question 24

fluoroscopic guidance remains the gold standard for

Answer 24

caudal epidural injection in adults

Question 25

fluoroscopy with epidurography can improve accuracy of blindly performed cervical ESIs by

Answer 25

ensuring correct needle placement and delivery of medication to the area of pathology

Question 26

use of fluoroscopy

with contrast epidurography should increase

Answer 26

accuracy of needle placement in the epidural space and targeted delivery of injected medication to the site of pathology, which may often be unilateral spread into the anterior epidural space.

Question 27

Complications of ESI can be separated into

Answer 27

those related to epidural technique and those related to injected
drugs.

Question 28

Technical side effects include

Answer 28

back pain at the injection site and temporarily increased radicular pain
and paresthesias without persistent morbidity.

Question 29

occur during procedures performed with the patient in the sitting position.

Answer 29

Acute anxiety, lightheadedness, diaphoresis, flushing, nausea, hypotension, and vasovagal syncope

Question 30

the most common complication of epidural injection.

Answer 30

Headache may occur after accidental dural puncture

Question 31

Side effect observed after

cervical ESI

Answer 31

Nonpostural headache

due to subarachnoid air injection, Pneumocephalus

Question 32

associated with rapid,

large-volume caudal steroid injection performed under general anesthesia.

Answer 32

Retinal hemorrhage

Question 33

epidural hematoma formation complication

Answer 33

acute paraplegia

Question 34

Tuohy needle insertion for cervical ESI complication

Answer 34

• bilateral upper extremity
• radicular pain
• anterior spinal subdural hematoma
• intrinsic spinal cord damage and permanent neurologic symptoms
• paraplegia (occurred secondary to either a discal herniation or cord ischemia due to dominant radiculomedullary artery injury similar to the injuries described clasically with transforaminal techniques)

Question 35

essential to reduce the risk of permanent neurologic deficit from epidural hematoma

Answer 35

Early diagnosis of epidural hematoma and immediate surgical decompression and evacuation

Question 36

Minor complications

that came to full resolution within 24 hr, such as

Answer 36

flushing, vasovagal episodes, exacerbation of symptoms, and insomnia,

Question 37

complications

could be reduced with

Answer 37

increased level of expertise, fluoroscopic
guidance, placement of needle at C6–C7 or lower
(where the epidural space is more capacitant), and with preinjection review of patient imaging

Question 38

Infectious complications of ESI include

Answer 38

bacterial meningitis

and epidural abscess.

Question 39

How did patients with epidural abscess present

Answer 39

3 days to 3 weeks after injection with fever, spinal pain, radicularpain, or progressive neurologic deficit;

Question 40

treatment of epidural abscess

Answer 40

Rapid diagnosis and therapy, including surgical drainage, appears
necessary if one hopes to achieve patient recovery with intact neurologic function. Magnetic resonance imaging (MRI) appears to be the procedure of choice for the diagnosis of epidural abscess

Question 41

predispose patient to epidural abscess formation

Answer 41

combination of diabetes

and steroid immunosuppression

Question 42

major important components of

aseptic technique

Answer 42

removal of watches and jewelry, antiseptic
hand washing, protective barriers, hats and masks,
sterile gloves, proper choice and use of skin sterilizing solution, proper draping and maintenance of sterile field, and proper dressing technique.

Question 43

Complications related to the drugs used for ESI include

Answer 43

pharmacologic effects of steroids and possible neurotoxity.Temporary development of Cushing’s syndrome, weight gain, fluid retention, hyperglycemia, hypertension, and congestive heart failure have all been reported after ESI.

Question 44

Effects of ESI on adrenals

Answer 44

Adrenal suppression is a well-known result of ESI. Plasma cortisol levels are decreased for up to 3 weeks after epidural injection of 80 mg of methylprednisolone acetate

Question 45

Neurotoxicity has been attributed to

Answer 45

spinal injections

of depot steroids or to their preservatives.

Question 46

reported after repeated intrathecal steroid injections in patients with multiple sclerosis.

Answer 46

Adhesive arachnoiditis. There are no case reports of arachnoiditis after ESI
alone.

Question 47

intraspinal methylprednisolone acetate recommended against its intrathecal use because of

Answer 47

potential polyethylene glycol toxicity.

Question 48

several recommendations

to avoid further complications of ESI

Answer 48

meticulous aseptic technique, especially in diabetic patients, to prevent infectious sequelae.

Question 49

Placing a needle transforaminally should theoretically result in a

Answer 49

a better delineation of the nerve root and possibly

better anterior epidural spread

Question 50

concerns associated with transforaminal injection

Answer 50

With the concerns over
neurologic injury associated with transforaminal injection,
interlaminar injections still remain very common, especially at the cervical level.

Question 51

Advantages of interlaminar injections

Answer 51

interlaminar injections are

simpler to perform for those with less expertise in fluoroscopy and less interventional pain experience

Question 52

A great limitation

with the interlaminar approach

Answer 52

is the obliteration of the posterior epidural space from previous surgery, which would make needle entry into the posterior epidural space more difficult.

Question 53

indications for ESI

Answer 53

with acute radicular pain, herniated disc, or new radiculopathy
superimposed on chronic back pain or cervical
spondylosis, lumbosacral radicular pain syndromes.

Question 54

required to justify use of ESI

Answer 54

The presence of nerve root irritation

Question 55

ESI should be avoided if there is

Answer 55

concern about localized or
systemic infection or clotting function. One should also consider the added risk of infection with diabetes and the reduced chance of success if there has been previous back
surgery, prolonged symptoms, substance abuse, disability, or litigation issues

Question 56

employed as the steroid drug

Answer 56

Methylprednisolone acetate 80 mg, or triamcinolone diacetate. The diluent
usually is normal saline, with the total being 3 to 5 ml at
the lumbar level, 2 to 4 ml at the cervical level, and 10 to
15 ml when the caudal approach is selected

Question 57

Lumbar ESI is performed

Answer 57

as close to the level of radicular pathology as
possible, often using a paramedian approach to target the lateral aspect of the interlaminar epidural space on the involved side.

Question 58

Cervical ESI is most often performed at

Answer 58

the C7–T1 level; entry at higher levels is not advisable because of the noncontinuity of the ligament flavum at
these levels. A guided epidural catheter is inserted and advanced to the desired level under fluoroscopic control.

Question 59

Rules of repeat injection

Answer 59

The injection is not repeated if there is complete relief. If partial relief occurs, a second injection is offered, but a third injection is only rarely used. Repeat injections are not offered when benefit is transient, but may be considered after prolonged responses of 6 to 12 months or longer.

Question 60

Exclusion criteria of ESI

Answer 60

ESIs should play a role as part of a multidisciplinary plan to manage back, neck, and radicular pain syndromes. With exclusion of patients who may not tolerate steroid medications
(or dosing alterations) and with exclusion of patients
with significant infection control problems and
bleeding diathesis

Question 61

Positive Factors

Answer 61

History

• Radicular pain
• Radicular numbness
• Short symptom duration
• Absence of significant psychological factors

Examination

• Dermatomal sensory loss
• Motor loss correlated to symptoms
• Positive straight-leg raise

Laboratory

• Abnormal EMG findings related to symptoms
• Lumbar herniated disc
• Cervical spondylosis

Question 62

Evaluation Criteria: Selection of Patients for Epidural Steroid Injection

Negative Predictive Factors

Answer 62

History

• Axial pain primarily
• Work-related injury
• Unemployed due to pain
• High number of past treatments
• High number of drugs taken
• Compensation due to pain
• Litigation pending
• Previous back surgery
• Smoking history
• Very high pain ratings

Examination
- Myofascial pain prominent

Laboratory

• Normal cervical spine imaging results
• Cervical herniated disc

Question 63

Evaluation Criteria: Selection of Patients for Epidural Steroid Injection

Increased Risk

Answer 63

Immunosuppression
Diabetes
Peptic ulcer disease
Tuberculosis
AIDS
Bacterial infection