Chapter 8. Pain Management Techniques Flashcards
1
Q
626. Which of the following is the most common microbe that grows in cultures of infected intrathecal pump wounds? (A) Pseudomonas species (B) Escherichia coli (C) Staphylococcus aureus (D) Staphylococcus epidermidis (E) None of the above
A
- (D)
A. Pseudomonas species grew in 3% of infected
wound cultures.
B. Escherichia coli is probably among the
unknown or not reported 20% or the multiple
or other species (7%).
C. and D. Staphylococcus species grew in cultures
of infected sites 59% of the time. Most
reports did not specify whether the cultured
Staphylococcus organisms were S aureus
or S epidermidis. However one study specifically
emphasized S epidermidis, which
arises from the skin of the patient or operating
room personnel, as the most likely
culprit. No growth took place in 9% of the
infected-wound cultures. No positive fungal
cultures were reported.
2
Q
627. You think a patient has developed an intrathecal catheter-tip inflammatory mass. What signs and symptoms would support this finding? (A) Diminishing analgesic effects (B) Pain that mimics nerve root compression (C) Pain that mimics cholecystitis (D) A and B (E) A, B, and C
A
- (E)
A. Subtle prodromal signs and symptoms
during early growth of a catheter-tip mass
include decreasing analgesic effects (loss
of previously satisfactory pain relief) and
unusual increase in the patient’s underlying
pain. Another occurrence was that
patient required unusually frequent or
high dose escalations to obtain analgesia.
In certain instances, dose increases and
large drug boluses reduced the patient’s
pain only temporarily or to a lesser degree
than previous experiences predicted.
B. Catheter-tip masses in the lumbar region
sometimes simulated nerve root compression
from a herniated intervertebral disc
or spinal stenosis.
C. When the catheter tip is located in the thoracic
region, early signs and symptoms of
an extra-axial inflammatory mass sometimes
included thoracic radicular pain that
stimulated intercostal neuralgia or cholecystitis.
Gradual, insidious neurologic deterioration
weeks or months after the appearance
of subjective symptoms was the most
common clinical course before the onset of
myelopathy or cauda equina syndrome.
Myelopathy is a term that means that
there is something wrong with the spinal
cord itself. This is usually a later stage of
cervical spine disease, and is often first
detected as difficulty while walking
because of generalized weakness or problems
with balance and coordination. This
type of process occurs most commonly in
the elderly, who can have many reasons for
troubled walking or problems with gait
and balance. However, one of the more
worrisome reasons that these symptoms
are occurring is that bone spurs and other
degenerative changes in the cervical spine
are squeezing the spinal cord. Myelopathy
affects the entire spinal cord, and is very
different from isolated points of pressure
on the individual nerve roots. Myelopathy
is most commonly caused by spinal stenosis,
which is a progressive narrowing of the
spinal canal. In the later stages of spinal
degeneration, bone spurs, and arthritic
changes make the space available for the
spinal cord within the spinal canal much
smaller. The bone spurs may begin to press
on the spinal cord and the nerve roots, and
that pressure starts to interfere with how the nerves function normally. Myelopathy
can be difficult to detect, because this disease
usually develops gradually and also
occurs at a time in life when people are
beginning to slow down a little bit anyway.
Many people who have myelopathy will
begin to have difficulty with activities that
require a fair amount of coordination, like
walking up and down the stairs or fastening
the buttons on clothing. If a patient has
had a long history of neck pain, changes in
coordination, recent weakness, and difficulty
doing tasks that used to be easier
because your body seemed more responsive
in the past, are definite warning signs
that they should see a doctor. Surgery is
usually offered as an early option for people
with myelopathy who have evidence of
muscle weakness that is being caused by
nerve root or spinal cord compression. This
is because muscle weakness is a definite
sign that the spinal cord and nerves are
being injured (more seriously than when
pain is the only symptom) and relieving
the pressure on the nerves is more of an
urgent priority. However, the benefits of
nerve and spinal cord decompression have
to be weighed against the risks of surgery.
Many people who have myelopathy
caused by degenerative cervical disorders
are older and often a bit frail. Spine surgery
can be a difficult stress for someone who is
old or who has many different medical
problems. However, a surgeon will be able
to discuss the risks and benefits of surgery,
and what the likely results are of operative
versus nonoperative treatment.
Cauda equina syndrome is a serious
neurologic condition in which there is
acute loss of function of the neurologic
elements (nerve roots) of the spinal canal
below the termination (conus) of the
spinal cord. After the conus the canal contains
a mass of nerves (the cauda equina—
horse tail—branches off the lower end of
the spinal cord and contains the nerve
roots from L1-5 and S1-5. The nerve roots
from L4-S4 join in the sacral plexus which
affects the sciatic nerve which travels caudally
(toward the feet). Any lesion which
compresses or disturbs the function of the
cauda equina may disable the nerves
although the most common is a central
disc prolapse. Other causes include protrusion
of the vertebra into the canal if
weakened by infection or tumor and an
epidural abscess or hematoma. Signs
include weakness of the muscles innervated
by the compressed roots (often
paraplegia), sphincter weaknesses causing
urinary retention and postvoid residual
incontinence. Also, there may be
decreased rectal tone; sexual dysfunction;
saddle anesthesia; bilateral leg pain and
weakness; and absence of bilateral ankle
reflexes. Pain may, however, be completely
absent; the patient may complain
only of lack of bladder control and of saddle-
anesthesia, and may walk into the
consulting-room. Diagnosis is usually
confirmed by an MRI scan or a CT scan,
depending on availability. If cauda equina
syndrome exists, early surgery is an
option depending on the etiology discovered
and the patient’s candidacy for major
spine surgery.
Awareness of these two phenomena and
maintenance of an index of suspicion are
important factors to help physicians detect
such inflammatory masses early in the clinical
course.
An inflammatory mass or granuloma is
resulted from a buildup of inflammatory
material at the tip of the catheter. Signs and
symptoms that warrant prompt diagnosis
to rule out the presence of a catheter-tip
mass include changes in the patient’s neurologic
condition, including motor weakness,
such as gait difficulties; sensory loss,
including proprioceptive loss; hyper- or
hypoactive lower extremity reflexes; and
any evidence of bowel or bladder sphincter
dysfunction. The practitioner should also
be suspicious of new or different reports of
numbness, tingling, burning, hyperesthesia,
hyperalgesia, or the occurrence of pain
(especially radicular pain that corresponds
to the level of the catheter tip) during
catheter access port injections or programmed
pump boluses. The latter finding should alert the physician to discontinue
the procedure and perform a diagnostic
imaging study as soon as possible.
If signs and symptoms suggestive of a
catheter-tip mass are detected, the practitioner
should first review the patient’s
current issues, history, and neurologic
examination. Then, a nonsurgical pain practitioner
should review imaging studies with
a neurosurgeon. Third, the physician should
arrange the performance of a definitive
diagnostic imaging procedure to confirm or
rule out the suspected diagnosis. Treatment
should be started in a timely fashion.
Laboratory tests and electromyography or
nerve conduction studies are not apparently
useful in this situation.
3
Q
628. Advantages of intrathecal drug-delivery are (A) the first-pass effect can be avoided (B) intrathecal morphine is 300 times as effective as oral morphine for equipotent pain treatment (C) the number of central nervous system (CNS) derived side effects can be reduced (D) B and C (E) A, B, and C
A
- (E)
A. The premise behind intrathecal drug
delivery is that by directly depositing
drugs into the CSF, the first-pass effect is
avoided.
B. Intrathecal morphine is 300 times as effective
as oral morphine for equipotent pain
treatment. From spinal to epidural morphine
the conversion is in the ratio of 1:10.
From epidural to IV morphine the conversion
is in the ratio of 1:10. From IV to oral
morphine the conversion is in the ratio of
1:3, hence 10 × 10 × 3 = 300.
C. By the direct action of the medication, the
number of CNS-derived side effects can be
reduced.
4
Q
629. Which one of the following is not an item to contemplate prior to placing an intrathecal pump? (A) Does the patient have an acceptable physiologic explanation for the pain syndrome (B) Does the patient have a life expectancy of 3 months or longer (C) Psychologic clearance is not needed in the patient with cancer pain (D) How old is the patient (E) Has the patient been reasonably compliant with past treatment recommendations
A
- (D) In choosing the right patient for an intrathecal
drug-delivery system, several important
questions must be asked, like
A. Does the patient have an adequate physiologic
explanation for the pain syndrome?
Does the diagnosis require aggressive pain
treatment?
B. Does the patient have a life expectancy of
3 months or longer (required for both cancer
and noncancer patients)?
C. Is the patient psychologically stable? A
psychologist should assess the patient’s
mental status and stability prior to the
procedure. Outcomes have been shown to
deteriorate with the presence of untreated
depression, untreated anxiety disorders,
and suicidal or homicidal ideation. Results
have also been negatively influenced by
the presence of untreated illicit substance
dependence. The presence of a personality
disorder such as borderline, antisocial, or
multiple personality disorder should
cause extreme caution, with these patient
receiving implants only in extenuating circumstances.
Psychologic clearance is not
needed in the patient with cancer pain, but
many of these patients may benefit from
counseling to better cope with the disease
process.
E. Has the patient been reasonably compliant
with past treatments? Has the patient failed
other, less invasive therapies? What were
they? Were they documented? Do they
include physical therapy and oral medications?
Are more conservative therapies unacceptable,
not desired, or contraindicated? Do
the symptoms of pain affect the patient’s
ability to function? Does the patient have a
contraindication, such as a bleeding diathesis,
or a localized or systemic infection? Has
the patient had a successful intrathecal medication
trial? The physician should write a
detailed note regarding symptom relief, side
effects, and overall patient acceptance. Does
the patient have a realistic view of expectations?
Does the patient accept the risks of the
procedure/device and future medications?
5
Q
- Prior to implanting an intrathecal pump many
practitioners perform an intrathecal medication
trial. Significant parameters to consider
include
(A) delivery site
(B) type of medication
(C) whether the patient should be admitted
(D) A and B
(E) A, B, and C
A
- (D)
A. and B. There is a definite justification for a
trial that mimics the conditions that will be
achieved by the implanted system. Important
parameters include
• Site of medication delivery (intrathecal
versus epidural, and spinal level)
• Whether the medication is delivered as a
bolus or an infusion
• Infusion rate
• Dose/concentration range
• Length of trial
• Medication selected for trial
C. The patient should always be admitted
and observed after an intrathecal medication
trial. There was a comparison of trial
methods in pain patients (nociceptive,
neuropathic, or mixed) selected to have
intrathecal pump placement. In the final
analysis at 12 months after implantation, it
was determined that there was no significant
difference in trial method (single-shot
intrathecal, continuous intrathecal, or continuous
epidural) in outcomes with nociceptive
pain. However, in neuropathic
pain syndromes, the initial success of trial
was significantly better if a continuous
method was used. There was no difference
noted in trial through the epidural route
versus trial through the intrathecal route.
The main difference between successful
trials in patients with neuropathic pain
and mixed pain syndromes was the inclusion
of more than one medication to
improve the success of the trial.
Morphine has been approved by the
FDA for intrathecal drug-delivery systems,
and is often the first choice of drug
for trial. Local anesthetics or α-receptor–
acting drugs are sometimes added to the
trial in patients with burning or lancinating
extremity pain with hopes of improving
the success of the trial.
To be considered a success, the trial
should induce significant pain relief, with
minimal side effects, and noncancer patients
should obtain purposeful improvement of
function.
6
Q
- When dealing with an infection, which of the
following would favor explanting the intrathecal
device?
(A) Associated bleeding
(B) The presence of a seroma
(C) The presence of a hygroma
(D) The presence of necrotic tissue around
the wound
(E) All of the above
A
- (D)
A. Bleeding at the wound site will be obvious
with seepage into the dressing. Associated
signs include edema, discoloration, and
rubor. It can usually be treated with ice and
compression; however, surgical exploration
may be necessary. The presence of an active
bleed does not necessitate the explantation
of the intrathecal drug-delivery system.
B. A seroma is a collection of noninfectious
fluid. It is usually treated with pressure
dressings and conservatively allowing for
resorption. If conservative treatment is not
efficacious, sterile aspiration may be necessary.
Its presence does not require the
removal of the intrathecal pump.
C. A hygroma is a collection of CSF. Its most
common cause is leakage of fluid around
the catheter entry point and into the
pocket. It can be treated with abdominal
pressure, caffeine, and increased fluid
intake.
D. Infection of the wound may be minor and
superficial, or it may be severe enough to
warrant the removal of the pump. An
infection may present with fever, redness,
frank pus, or purulent wound drainage.
Incision and drainage, qualification of
pathogenic culprit, and antibiotic therapy
must be undertaken immediately. The
decision to excise the pump is made based
on the presence of necrotic tissue, the overall
condition of the wound, and the condition
of the patient.
The two most disastrous complications
are epidural hematoma and neuraxial
infection. An epidural hematoma may
result in paralysis and should be suspected
with any change in neurologic status
postoperatively. This is an emergency
and an immediate MRI and neurosurgical
consultation should be obtained. The presence
of an intrathecal pump is not a contraindication
to MRI, and should not delay
its use. A neuraxial infection can include
meningitis or an epidural abscess and they
must both be diagnosed immediately so
that treatment can be started expeditiously.
7
Q
- You have separately tried maximum doses of
morphine and hydromorphone, in a patient’s
intrathecal pump without any efficacy. According
to the 2007 Polyanalgesic Consensus Guidelines,
which one of the following would not be an
accepted “next” step?
(A) Switch to morphine plus bupivacaine
(B) Switch to ziconotide
(C) Switch to clonidine
(D) Switch to fentanyl
(E) Switch to hydromorphone plus
ziconotide
A
- (C) For the 2007 Polyanalgesic Consensus
Guidelines, baclofen and midazolam were
moved to special consideration categories.
Midazolam may be used in end of life situations
but only minimal/anecdotal evidence
exists. Baclofen is to be used in patients that
have spasticity-related pain, diseases associated
with dystonia, or unrelenting spasms in
muscle. It works via blockade of GABAB receptors
in the spinal cord. Indications for intrathecal
baclofen therapy: patient is intolerant of
oral agents, pain is inadequately treated with
oral agents, need exact control of dosing that only intrathecal delivery allows. Efficacy in
neuropathic pain has been noted through case
reports at doses of 100 to 460 μg/d (maximum
FDA dosing is 900 μg/d). If significant dose
increases are taking place, consider mechanical
problems. Very good for exceptional long-term
tolerability is expected. However, baclofen is
not without complications. Withdrawal can
occur secondary to catheter disruption, battery
failure, or human error. There is a very wide
spectrum of presentation ranging from asymptomatic
to death. Granulomas are very rare.
Overdose is usually results from human error
and can be reversed with physostigmine, and
flumazenil.
8
Q
- Ziconotide was approved for infusion into the
cerebrospinal fluid (CSF) using an intrathecal
drug-delivery system by the Food and Drug
Administration (FDA) in 2004. Its proposed
mechanism of action is
(A) it blocks sodium channels
(B) it blocks α2δ voltage-gated calcium
channels
(C) it blocks N-type calcium channels
(D) it blocks γ-aminobutyric acid (GABAB)
receptors in the spinal cord
(E) none of the above
A
- (C)
A. Numerous medications work by blocking
sodium channels. Ziconotide is not one of
them.
B. Pregabalin and gabapentin work by acting
on α2δ voltage-gated calcium channels. Their
exact mechanism of action is unknown, but
their therapeutic action on neuropathic pain
is thought to involve voltage-gated N-type
calcium ion channels. They are thought to
bind to the α2δ subunit of the voltagedependent
calcium channel in the CNS.
C. Ziconotide is a nonopioid, non-NSAID
(nonsteroidal anti-inflammatory drug),
nonlocal anesthetic used for the amelioration
of chronic pain. Derived from the cone
snail Conus magus, it is the synthetic form
of the cone snail peptide ω-conotoxin MVII-
A. Previously known as SNX-111, it is a
neuronal-specific calcium-channel blocker
that acts by blocking N-type, voltage-sensitive
calcium channels.
Scientists have been intrigued by the
effects of the thousands of chemicals in
marine snail toxins since the initial investigations
in the late 1960s by Baldomero
Olivera, who remembered the deadly
effects from his childhood in the
Philippines. Ziconotide was discovered in
the early 1980s by Michael McIntosh, at
the time barely out of high school and
working with Olivera. It was developed
into an artificially manufactured drug by
Elan Corporation. It was approved for
sale under the name Prialt by the FDA in
the United States on December 28, 2004,
and by the European Commission on
February 22, 2005.
The mechanism of ziconotide has not
yet been discovered in humans. Results in
animal studies suggest that ziconotide
blocks the N-type calcium channels on the
primary nociceptive nerves in the spinal
cord.
As a result of the profound side effects
or lack of efficacy when delivered through
more common routes, such as orally or
intravenously, ziconotide must be administered
intrathecally (directly into the
spine). As this is by far the most expensive
and invasive method of drug delivery and
involves additional risks of its own,
ziconotide therapy is generally considered
appropriate (as evidenced by the range of
use approved by the FDA in United States)
only for management of severe chronic
pain in patients for whom intrathecal (IT)
therapy is warranted and who are intolerant
of or refractory to other treatment,
such as systemic analgesics, adjunctive
therapies or IT morphine.
The most common side effects are dizziness,
nausea, confusion, and headache.
Others may include weakness, hypertonia,
ataxia, abnormal vision, anorexia, somnolence,
unsteadiness on feet, and memory
problems. The most severe, but rare side
effects are hallucinations, suicidal ideation,
new or worsening depression, seizures, and
meningitis. Therefore, it is contraindicated
in people with a history of psychosis, schizophrenia,
clinical depression, and bipolar
disorder.
D. Baclofen’s proposed mechanism of action
is by blocking the GABAB receptors in the
spinal cord.
9
Q
- Neurology consults you on a 65-year-old female
with breast cancer that has diffusely metastasized
to her bones. She has had an intrathecal
pump for 4 months, and has just been diagnosed
with meningitis. Which of the following
is true?
(A) The pump must be removed
(B) Enteral antibiotics must be initiated
immediately
(C) If the infection is sensitive to vancomycin,
and the patient refuses pump
removal, intrathecal vancomycin may be
administered
(D) Intravenous (IV) vancomycin plus
epidural vancomycin has not been
found to be effective in resolving infection
(E) All of the above
A
- (C)
A. The diagnosis of aseptic or viral meningitis
in the cancer patient with an intrathecal
pump should not be an automatic reason
for explantation of the device. Supportive care and neurologic monitoring should be
provided until the symptoms resolve, but
the pump and catheter do not need to be
removed. If the meningitis is of a bacterial
etiology, risk assessment, pain stratification,
and life expectancy should be considered.
Removal of the pump is suggested,
but is not required because there is a
potential for severe, uncontrolled pain.
B. Parenteral (IV) not enteral (via the GI tract)
antibiotics should be started immediately
if bacterial meningitis is suspected. More
specific antibiotics should be administered
after cerebrospinal bacterial cultures and
sensitivities are obtained.
C. If the infection is vancomycin sensitive,
and the patient refuses pump explantation,
intrathecal vancomycin may be administered
at 10 mg/d. Intrathecal vancomycin
has been used successfully for 6 months in
such patients.
D. The same group found that IV vancomycin
combined with epidural vancomycin
(150 mg/d for 3 weeks) abolished infection.
10
Q
- A 72-year-old male with end-stage metastatic
prostate cancer has a life expectancy of 6 months.
Which of the following is true with regards to
managing his intrathecal drug-delivery system?
(A) Treatment decisions should be made
based on the 2007 Polyanalgesic
Consensus Guidelines for management
of chronic, severe pain
(B) Fentanyl is considered a first-line
medication
(C) Droperidol may be used, intrathecally,
as a first-line medication for nausea
(D) A different algorithm is applied when a
patient’s life expectancy is less than
18 months
(E) None of the above
A
635. (C) B. and C. Morphine or hydromorphone should be used for nociceptive pain. Bupivacaine should be used for neuropathic pain. Morphine or hydromorphone plus bupivacaine should be used for mixed pain. Droperidol is 95% efficacious in the treatment of nausea and vomiting secondary to opioid intolerance, abdominal tumors, and/or chemotherapy/radiation therapy, and can be added at this point (dose: 25-250 μg/d). Morphine, hydromorphone, or fentanyl/ sufentanil with bupivacaine and clonidine for nociceptive or mixed pain. Morphine, hydromorphone, or fentanyl/ sufentanil with bupivacaine for neuropathic pain. Morphine, hydromorphone, or fentanyl/ sufentanil with more than two adjuvants: the physician should use opiate plus local anesthetic plus clonidine and • Baclofen for spasticity, myoclonus, or neuropathic pain • Bupivacaine for neuropathic pain • Second opioid (lipophilic/hydrophilic) as an adjuvant Morphine, hydromorphone, or fentanyl/ sufentanil with more than three adjuvants: in addition to second-line adjuvants, the physician should add • Ketamine for neuropathic pain secondary to cord compression • Midazolam for neuropathic pain • Droperidol for neuropathic pain Tetracaine may be used for chemical paralysis for inoperable cord compression, tachyphylaxis, or emergency hyperalgesia rescue. Some cases may necessitate six adjuvants to control pain at the end of life with minimal side effects.
11
Q
636. Granulomas have been found to occur with all medications used intrathecally, EXCEPT (A) clonidine (B) sufentanil (C) baclofen (D) fentanyl (E) B and D
A
- (B) The 2007 Polyanalgesic Consensus
Guideline panelists have addressed this topic
fully. All panelists felt that catheter-related
granulomas still remains one of the most grave
adverse effects and risks of intrathecal pain
management and impediments to the widespread
use of the therapy. Several factors contribute
to the development of granuloma,
including the agent used, catheter position
(majority of granulomas occur in thoracic
area—where CSF volume and flow are
reduced), CSF volume (especially if low), and
the dose and concentration of the drug (low
CSF volume means higher concentrations of
drug). With morphine, the preponderance of
cases have been described in patients receiving
concentrations of 40 mg/mL or greater. In cases
where hydromorphone was implicated, the
majority of cases received concentrations of
10 mg/mL or greater. Even though some panelists
felt that positioning the catheter into the
larger CSF volume of the dorsal intrathecal
space of the low thoracic cord, granulomas do
occur even in cases where catheters have been
inserted into that space. However, concentration
of the agent used appears to be the major
causal factor of intrathecal, catheter-related
granulomas. A., B., C., and D. Inflammatory masses
have been reported to be associated with all
medications administered in the intraspinal
space except for sufentanil and rarely for fentanyl.
As of this writing, there have been at
least three reports published in the literature
of baclofen-related granulomas. Even though
the literature suggests a granuloma protective
effect of clonidine, there have been reports of
patients with intrathecal clonidine, alone, or
in combination with other intrathecal agents
developing granulomas.
12
Q
Match the associated side effects with the intrathecal medication that causes it. Each choice can be used once, more than once, or not at all, and each question can have more than one answer. 637. Urinary retention 638. Extrapyramidal side effects 639. Hypotension 640. Auditory disturbances 641. Sedation 642. Nausea 643. Worsening of depression (A) Opioids (B) Bupivacaine (C) Baclofen (D) Clonidine (E) Droperidol (F) Ketamine (G) Midazolam
A
637 to 643. 637 (A and B); 638 (E); 639 (B and D);
640 (C); 641 (A, D, and G); 642 (A); 643 (D)
Opioids can cause sedation, edema, constipation,
nausea, and urinary retention.
Bupivacaine can cause urinary retention,
weakness, and hypotension.
Baclofen can cause loss of balance, and auditory
disturbances.
Clonidine can cause orthostatic hypotension,
worsening of depression, edema, and sedation.
Droperidol can cause extrapyramidal side
effects such as tremor, slurred speech, akathisia,
dystonia, anxiety, distress, and paranoia.
Ketamine can cause increased anxiety and
irritability, delusional ideation, and facial
flushing.
Midazolam can cause sedation.
If a medication is not therapeutic for a
patient or is causing significant adverse effects,
it should be properly weaned, and the patient
should be informed of likely withdrawal
symptoms and arrange for outpatient interventions.
Acute baclofen or clonidine termination
can result in hemodynamic derangements,
seizures, or death. To avoid these untoward
effects, physicians should introduce oral
replacement therapy on the stoppage of
intrathecal medications and provide an appropriate
weaning schedule to the patient.
13
Q
- A 43-year-old female has 8-month history of
axial low back pain and pain radiating to the
left leg. The magnetic resonance imaging (MRI)
of lumbosacral spine shows severe degenerative
disc disease at L3-4 through L5-S1 with
mild disc protrusions at these levels. She is a
possible candidate for
(A) transforaminal epidural steroid injection
(B) facet joint medial branch diagnostic
block
(C) spinal cord stimulator (SCS) trial
(D) all of the above
(E) none of the above
A
- (D)
A. The epidural steroid injections (ESI) and
SCS are treatment choices for radicular
pain caused in particular by disc herniation causing mechanical and chemical irritation
of the nerve root.
B. Presence of axial low back pain even in
absence of MRI changes can indicate possible
facet arthropathy. Facet and medial
branch diagnostic blocks are likely the
most sensitive and specific diagnostic test
for facet pain. Facet radiofrequency (RF)
denervation seems to be the best treatment
choice for patients with short-term relief
with facet blocks.
C. The SCS trial may be an excellent choice
for radiating pain down the leg.
14
Q
645. The causes of axial low back pain are (A) sacroiliac (SI) arthropathy (B) internal disc disruption (C) quadratus lumborum and psoas syndrome (D) all of the above (E) none of the above
A
- (D)
A. SI joint injection with local anesthetics and
steroids may have good diagnostic and
possibly therapeutic value if the pain is
located in the SI joints.
B. Internal disc disruption or discogenic
pain can be diagnosed with provocative
discography.
C. Quadratus lumborum and psoas muscle
pain represent a form of myofascial pain
that can be a cause of low back pain.
Diagnostic blocks may have a value in diagnosis
of this type of myofascial pain.
15
Q
646. The false-positive rate of diagnostic lumbar facet medial branch blocks are (A) 8% to 14% (B) 15% to 22% (C) 3% to 5% (D) 25% to 41% (E) 41% to 50%
A
- (D) Diagnostic medial branch blocks have a
very high false-positive rate as reported in
studies. This can potentially decrease the success
rate of RF denervation of facet joints since
this procedure is based on good short-term
results with diagnostic medial branch blocks.
For this reason repeated confirmatory diagnostic
block and use of small dose of local anesthetics
(0.3-0.5 mL) is recommended by many.
16
Q
647. Percentage of cases where the pain relief is caused by placebo response following interventional procedures are (A) 12% (B) 35% (C) 20% (D) 15% (E) 28%
A
- (B) Placebo effect is responsible for pain relief
in up to 35.2% interventional procedures.
Despite the high rates of placebo response it is
not recommended for routine clinical use.
17
Q
648. The complication of sphenopalatine ganglion radiofrequency thermocoagulation is (A) infection (B) epistaxis (C) bradycardia (D) all of the above (E) none of the above
A
- (D)
A. Infection is a rare complication that can be
difficult to treat.
B. It seems that the epistaxis is more common
than thought and can occur if too much pressure is applied to the RF cannula.
Hematoma can occur if maxillary artery of
venous plexus is punctured.
C. Bradycardia is likely caused by reflex similar
to the oculocardiac reflex.
18
Q
649. The complication of third occipital nerve (TON) radiofrequency thermocoagulation is (A) change in taste (B) ataxia (C) dysphagia (D) all of the above (E) none of the above
A
- (B)
A. Change in taste would more likely be associated
with glossopharyngeal nerve, lingual
nerve, and chorda tympani.
B. Ataxia can occur in up to 95% cases of RF
denervation of the TON, numbness in 97%,
dysesthesia in 55%, hypersensitivity in
15%, and itching in 10% of cases. Third
occipital neurotomy almost always partially
denervates semispinalis capitis muscle
and so interferes with tonic neck
reflexes and causes ataxia in particular on
looking downward. The sensation is readily
overcome by relying on visual cues such
as fixing on the horizon.
C. Dysphagia is not associated with TON
thermocoagulation
19
Q
- Positive lumbar provocative discogram for
mechanical disc sensitization includes reproduction
of patient’s pain with injection of the
contrast in nucleus pulposus at what pressure
above the “opening pressure”?
(A)
A
- (D)
A. Provocative discography is best done while
pressure of contrast has been continuously
measured. Reproduction of pain at 6/10
and pain location and quality should be
similar to the chronic low back pain.
20
Q
651. The technique of cervical discography includes needle entry through the skin from the (A) anterior right side of the neck (B) posterior right side of the neck (C) anterior left side of the neck (D) posterior left side of the neck (E) median posterior side of the neck
A
- (A) Cervical discography is performed with
patient in supine position, using oblique
approach, similar to the stellate ganglion block.
The esophagus is normally positioned slightly toward the left side of the neck. To prevent
puncturing it, the best technique for needle
insertion for cervical discography is anterior
right-sided approach.
21
Q
- When performing intralaminar cervical epidural
steroid injections without fluoroscopic guidance,
the chances of having false positive loss
of resistance are close to
(A) 15%
(B) 25%
(C) 35%
(D) 50%
(E) 40%
A
- (D) The ligamentum flavum is discontinuous
in cervical levels, therefore allowing for very
high chances of false loss of resistance technique
and therefore mandates the use of fluoroscopy
and contrast administration. The use of
fluoroscopy may improve the safety of this procedure,
medication delivery to the site of
pathology, and potential outcomes. In lumbar
levels it seems that the false loss of resistance in
nonfluoroscopically performed epidural
steroid injections occurs in up to 30% of cases.
22
Q
- When performing intralaminar cervical epidural
steroid injections, the unilateral contrast (and
medication) spread is expected in what percentage
of cases?
(A) 50%
(B) 30%
(C) 25%
(D) 10%
(E) 40%
A
- (A)
A. Although there is no median septum of fat
in cervical epidural levels the unilateral
medication spread is common. Therefore
injections should be performed toward the
laterality of pathology.
B. False loss of resistance technique when not
performed under fluoroscopy is 30% in
lumbar levels and 50% in cervical levels.
C. Ventral epidural spread in cervical levels is
close to 25%.
D. Too low.
E. Unilateral contrast spread in intralaminar
cervical epidural injections may occur in
roughly 50% of all cases.
23
Q
654. Which of the following is a complication of lumbar sympathetic block? (A) Genitofemoral neuralgia (B) Retrograde ejaculation (C) Intravascular injection (D) All of the above (E) None of the above
A
- (D)
A. Genitofemoral neuralgia is very rare complication
of lumbar sympathetic block but
can occur since the genitofemoral nerve
originates from L1 and L2 nerve root.
B. In retrograde ejaculation, the bladder
sphincter does not contract and the sperm
goes to the bladder instead of penis. This
can lead to infertility.
C. Intravascular injection of large dose of
local anesthetics can lead to seizures.
24
Q
655. What is the best method for evaluating the adequacy of lumbar sympathetic block? (A) Increase in temperature by 2°F (B) Increase in temperature by 5°F (C) Increase in temperature by 10°F (D) Temperature change (E) Decrease in temperature by 2°F
A
- (D) Any temperature change in comparison to
preprocedure temperatures is adequate enough
to assess the adequacy of successful block.
25
Q
656. Stellate ganglion is located between the (A) C6-C7 (B) C7-T1 (C) C5-C7 (D) C5-C6 (E) T1-T2
A
- (B) The stellate ganglion is formed by fusion of
inferior cervical ganglion resting over the anterior
tubercle of C7 and first thoracic ganglion
resting over the first rib.
26
Q
657. In relation to the stellate ganglion the subclavian artery is located (A) anteriorly (B) posteriorly (C) laterally (D) medially (E) none of the above
A
- (A) In relation to stellate ganglion the subclavian
artery is located anteriorly. For this reason,
care should be taken not to inject
27
Q
- Despite satisfactory stellate ganglion block for
sympathetic-mediated pain, the pain relief in
upper extremity is inadequate. The technical explanation for this may lie in inadequate
spread of local anesthetics to
(A) C5 nerve root
(B) inferior cervical ganglion
(C) first thoracic ganglion
(D) T2 and T3 gray communicating rami
(E) C7 nerve root
A
- (D)
A. C5 nerve root injection may provide analgesia
by sensory block.
B. Inferior cervical ganglion is part of the stellate
ganglion.
C. First thoracic ganglion is part of the stellate
ganglion.
D. The T2 and T3 gray rami do not pass through
the stellate ganglion but join the brachial
plexus and innervate the upper extremity.
Failure to block these structures may result in
inadequate block (Kuntz nerves).
28
Q
- When performing lumbar discography, the
“opening pressure” is the recorded pressure
signifying
(A) first appearance of the contrast in
nucleus pulposus
(B) opening of the annular tear to the contrast
(C) reproduction of concordant pain
(D) resting pressure transduced from the
nucleus
(E) a dural leak
A
659. (A) A. The opening pressure is always subtracted from pressure reproducing pain in final calculations (eg, positive discography means: pressure with pain reproduction— opening pressure
29
Q
660. Intradiscal electrothermal coagulation (IDET) outcomes are adversely affected by (A) appearance of the disc on T2-weighted MRI images (B) obesity (C) age (D) coexisting radicular pain (E) gender
A
- (B)
A. Discs are usually dark (dehydrated) on T2-
weighted MRI images and this can only
suggest discogenic pain.
B. Morbid obesity can decrease the success
rate and increase the risks of IDET.
C. There are no studies proving that age
influences outcomes of IDET but it seems that advanced age may decrease the rate of
success of IDET treatment.
D. Radicular pain directly does not predict
the outcome of IDET. Discogenic pain
(referred pattern) can sometimes mimic
radicular pain.
30
Q
- When performing lumbar discography, in relation
to the laterality of pain, which of the following
should be the needle entry site?
(A) Ipsilateral
(B) Contralateral
(C) Laterality does not make a difference
(D) Guided by MRI images
(E) None of the above
A
- (C) It does not seem that the outcomes of
discography are affected by laterality of needle
insertion site.
31
Q
- Apatient with painful sacroiliac joint syndrome
had only short-term relief with two sacroiliac
(SI) injections using local anesthetics and
steroids. Which of the following is the next treatment
option?
(A) SI joint fusion
(B) S1, S2, S3, S4 radiofrequency
denervation
(C) L5, S1, S2, S3 radiofrequency
denervation
(D) L4, L5, S1, S2, S3 radiofrequency
denervation
(E) None of the above
A
- (D) SI joint fusion has been used in the past as
a treatment of SI pain with unfavorable results.
The L4, L5, S1, S2, and S3 radiofrequency
denervation is shown to be beneficial longterm
treatment option in patients with SI pain.
32
Q
663. Which of the following includes published complications that may follow cervical transforaminal epidural steroid injection? (A) Epidural abscess (B) Neuropathic pain (C) Quadriplegia and death (D) All of the above (E) None of the above
A
- (D)
A. Epidural abscess should be suspected if
increased pain and new neurologic symptoms
occur after the cervical epidural
steroid injection.
B. Neuropathic pain may occur following
epidural steroid injection.
C. If the steroid solution is injected intravascularly
serious complications including
possible spinal cord infarction may occur.
The digital subtraction fluoroscopy and
blunt needle use may help to minimize its
occurrence if this procedure is performed.
33
Q
- In order to minimize the risk for complications
when cervical transforaminal epidural steroid
injection is performed how should the needle be
positioned in relation to the neural foramina?
(A) Anteriorly
(B) Posteriorly
(C) Superiorly
(D) Inferiorly
(E) None of the above
A
- (B) Placing needle posteriorly may minimize
the risk of intravascular injection.
34
Q
- The single-needle approach to medial branch
block diagnosis in comparison to standard
multiple-needle approach
(A) causes less discomfort for the patient
(B) decreases the volume of local anesthetics
used for the skin and subcutaneous
tissues
(C) takes less time to perform
(D) all of the above
(E) none of the above
A
665. (D) A. The use of single-needle technique may decrease procedural discomfort during medial branch blocks. B. By minimizing the amount of local anesthetics for the skin and subcutaneous tissues the rate of false-positive blocks caused by treatment of myofascial pain may be diminished. C. This approach may take less time to perform than the traditional multiple-needle technique.
35
Q
666. The incidental intrathecal overdose of intrathecal morphine while performing a pump refill should be treated by (A) intrathecal and IV naloxone (B) airway protection (C) possible irrigation of the CSF with saline (D) all of the above (E) none of the above
A
- (D)
A. If IV naloxone is inadequate, intrathecal
naloxone may be considered.
B. Airway protection may be needed because
of respiratory depression.
C. Possible irrigation of CSF with saline may
be necessary.
36
Q
- While analyzing a malfunctioning SCS implanted
device, a sign of lead breakage or disconnect is a
measured impedance of
(A) 1500 Ω
(C) 4000 Ω
(E)
A
- (D) Increased impedance may mean that there
is lead fracture, disconnect, fluid leakage causing
short circuit. The exactly same impedance
at multiple leads may mean that there is a
communication and short circuit between the
leads.
37
Q
- Accurate placement of a stimulator lead for
occipital nerve peripheral stimulation is
(A) posterior to the C3 spinous process
(B) lateral to the pedicles of C2 and C3
(C) 2 mm lateral to the odontoid process
(D) posterior to the C2 spinous process
(E) none of the above
A
- (D) The lead should be positioned subcutaneously
posterior to the C2 spinous process
and perpendicular to the cervical spine.
38
Q
669. Adequate SCS introducer needle epidural space at entry level for the desired coverage of the foot pain is (A) L3-4 interspace (B) L1-L2 interspace (C) T12-L1 interspace (D) T8-T9 interspace (E) T10-T11 interspace
A
- (A) For the coverage of the foot, the SCS electrode
position should be at the T11-T12 level.
The more caudal entry level is desired in order
to leave enough of the SCS lead in the epidural
space and prevent dislodgement.
39
Q
670. The placement of SCS electrodes for coverage of intractable chest pain caused by angina should be at the epidural level of (A) T6 (B) C4-C5 (C) T1-T2 (D) C6-C7 (E) C3-C4
A
- (C) In order to position the lead at T1-T2 level
commonly the entry site may be at lower thoracic
levels owing to the narrow space in
between the laminae in thoracic spine.
40
Q
671. Most effective approach for performing lumbar epidural steroid injections is (A) caudal (B) interlaminar (C) paramedian approach (D) transforaminal (E) Taylor approach
A
- (D) Although there is insufficient evidence, one
study reported that transforaminal approach
has better outcomes in comparison to interlaminar
approach for epidural steroid injections.
The caudal approach requires diluted
solution and may not reach the area of pathology
in some cases.
41
Q
672. During interlaminar epidural steroid injections contrast should be (A) used in the anteroposterior view (B) used in the lateral view (C) used in oblique view (D) no contrast should be used (E) A, B, and C
A
- (A) Contrast media should be administered in
anteroposterior view in order to rule out
intravascular uptake.
42
Q
- Which of the following is the most likely complication
after successful SCS implant?
(A) Infection
(B) Persistent pain at the implant site
(C) Lead breakage or migration
(D) CSF leak requiring surgical intervention
(E) Paralysis or severe neurologic deficit
A
- (C)
A. Infection rate of implanted hardware has
been estimated at 3% to 5%.
B. Persistent pain at the implant site has been
estimated at approximately 5%.
C. Lead breakage or migration has been estimated
at 11% to 45%.
D. CSF leak requiring surgical intervention
has been reported.
E. Paralysis or severe neurologic deficit is
possible as with any type of spine surgery,
but is not cited as a frequent occurrence.
43
Q
- Which of the following is the most accurate
statement regarding efficacy of SCS?
(A) For failed back surgery patients, SCS in
addition to conventional medical management
can provide better pain relief
and improve health-related quality of
life as compared to conventional medical
management alone
(B) SCS is inefficacious for the indication of
angina pectoris
(C) SCS for CRPS is efficacious for only
about a year only then the efficacy
diminishes
(D) SCS is not an effective treatment for
sympathetically mediated pain
(E) Nociceptive pain is considered a better
indication for SCS than neuropathic
pain
A
- (A)
A. One study which validates this statement
was published in the journal Pain in 2007. A
randomized, crossover study was performed
with intent-to-treat analysis for
more than 12 months. One hundred
patients were randomized to either SCS
and conventional medical management or
conventional medical management only.
More patients in the SCS group achieved
the primary outcome of 50% or more pain
relief in the legs. Other secondary measures
were also improved in the SCS group.
[Kumar K, Taylor RS, Jacques L, et al. Spinal
cord stimulation versus conventional medical
management for neuropathic pain: a
multicenter randomized controlled trial in
patients with failed back surgery syndrome.
Pain. 2007;132(1-2):179-188.]
B. In a 2009 review article it was determined
that SCS decreases use of short-acting
nitrates, improves quality of life, and
increases exercise capacity. [Deer TR.
Spinal cord stimulation for the treatment of
angina and peripheral vascular disease.
Curr Pain Headache Rep. 2009;13(1):18-23.]
C. Many follow-up studies have been published
showing efficacy with short-term follow-
ups such as 6 months. A recent 5 year
follow-up of a randomized, controlled trial
of SCS for CRPS revealed that 95% of
patients would repeat the treatment for the
same result. Aretrospective telephone questionnaire
study was performed in 21 CRPS
patients with average follow-up at 2.7 years.
Reduced pain and improved quality of life
was sustained at long-term follow-up.
[Kemler MA, de Vet HC, Barendse GA, et al.
Effect of spinal cord stimulation for chronic
complex regional pain syndromes type I:
five-year final follow-up of patients in a randomized controlled trial. J Neurosurg.
2008;108(2):292-298.]
D. SCS is effective for the treatment of sympathetically
mediated pain.
E. This is a false statement. Neuropathic pain
has traditionally been considered an indication
for SCS. Nociceptive pain is considered
not amenable to treatment with SCS.
44
Q
675. Which of the following is not a relative contraindication to SCS? (A) Unresolved major psychiatric comorbidity (B) A predominance of nonorganic signs (C) Spinal cord injury or lesion (D) Alternative therapies with a risk to benefit ratio comparable to that of SCS remain to be tried (E) Occupational risk
A
- (C) In 2007, an article published an evidencebased
literature review and consensus statement
which addressed over 60 questions
relating to clinical use of SCS. Spinal cord
injury or lesion, is an etiology of neuropathic
pain and is an indication for SCS. Certain occupations
such as an electrician’s are considered
a relative contraindication to SCS therapy.
