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
  1. (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.
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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
  1. (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.
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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
  1. (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.
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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
  1. (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?
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5
Q
  1. 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
  1. (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.
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6
Q
  1. 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
  1. (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.
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7
Q
  1. 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
  1. (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.
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8
Q
  1. 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
  1. (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.
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9
Q
  1. 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
  1. (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.
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10
Q
  1. 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.
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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
  1. (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.
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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.

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13
Q
  1. 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
  1. (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.
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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
  1. (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.
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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
  1. (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.
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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
  1. (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.
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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
  1. (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.
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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
  1. (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
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19
Q
  1. 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
  1. (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.
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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
  1. (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.
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21
Q
  1. 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
  1. (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.
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22
Q
  1. 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
  1. (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.
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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
  1. (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.
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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
  1. (D) Any temperature change in comparison to
    preprocedure temperatures is adequate enough
    to assess the adequacy of successful block.
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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
  1. (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.
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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
  1. (A) In relation to stellate ganglion the subclavian
    artery is located anteriorly. For this reason,
    care should be taken not to inject
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27
Q
  1. 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
  1. (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).
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28
Q
  1. 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
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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
  1. (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.
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30
Q
  1. 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
  1. (C) It does not seem that the outcomes of
    discography are affected by laterality of needle
    insertion site.
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31
Q
  1. 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
  1. (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.
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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
  1. (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.
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33
Q
  1. 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
  1. (B) Placing needle posteriorly may minimize

the risk of intravascular injection.

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34
Q
  1. 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.
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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
  1. (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.
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36
Q
  1. 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
  1. (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.
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37
Q
  1. 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
  1. (D) The lead should be positioned subcutaneously
    posterior to the C2 spinous process
    and perpendicular to the cervical spine.
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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
  1. (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.
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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
  1. (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.
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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
  1. (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.
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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
  1. (A) Contrast media should be administered in
    anteroposterior view in order to rule out
    intravascular uptake.
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42
Q
  1. 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
  1. (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.
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43
Q
  1. 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
  1. (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.
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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
  1. (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.
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45
Q
  1. Which of the following statements is most
    accurate regarding cost-effectiveness of SCS?
    (A) Nobody opines of its cost-effectiveness
    and the issue has not been addressed in
    literature
    (B) The literature is clear and consistent;
    SCS is not cost-effective
    (C) Although published conclusions may
    vary, a consensus of professionals has
    determined that SCS stimulation is not
    cost-effective
    (D) Although published conclusions may
    vary, a consensus of professionals has
    determined that SCS is cost-effective for
    certain indications
    (E) All published literature on the topic
    concludes that SCS is cost-effective
A
  1. (D) Some published articles concluded that
    SCS is cost-effective. Some have concluded that
    SCS is not cost-effective, at least in certain
    patient populations. Variation may relate to
    specific parameters and patient inclusions in
    the study. Recent practice parameters concluded
    that SCS is cost-effective in the treatment of
    failed back surgery syndrome and CRPS and
    might be cost-effective in the treatment of other
    neuropathic pain indications. Furthermore it
    was concluded that cost-effectiveness can be
    optimized by adjusting stimulation parameters
    to prolong battery life, by minimizing complications,
    and by improving equipment
    design. [Mekhail NA, Aeschbach A, Stanton-
    Hicks M. Cost benefit of neurostimulation for
    chronic pain. Clin J Pain 2004;20(6):462-468.
    Klomp HM, Steyerberg EW, van Urk H,
    et al. Spinal cord stimulation is not cost-effective
    for non-surgical management of critical
    limb ischemia. Eur J Vasc Endovasc Surg.
    2006;31(5): 500-508.
    North R, Shipley J, Prager J, et al. Practice
    parameters for the use of spinal cord stimulation
    in the treatment of chronic neuropathic
    pain. Pain Med 2007;8(suppl 4):S200-S275.]
46
Q
677. Which of the following are specifications for
current SCS systems?
(A) Constant voltage, pulse width up to
2000 milliseconds
(B) Constant current, volume less 10 cm3
(volume less than a standard matchbook)
(C) Constant resistance, pulse width up to
1000 milliseconds, cordless recharging
(D) Constant current, pulse width up to
1000 milliseconds, cordless recharging
(E) Constant current and constant resistance,
cordless recharging, pulse width
up to 1000 milliseconds
A
  1. (D)
    A. One of the three commonly used manufacturers
    does use a constant voltage technology.
    None of the three manufacturers have
    a system allowing pulse width much over
    1000 milliseconds.
    B. Two of the three commonly used manufacturers
    do use a constant current technology.
    Although battery sizes as small as
    22 cm3 are available with two companies,
    no company currently has a battery
    smaller than that in current clinical usage.
    This may change in the near future.
    C. No SCS system relies on maintaining constant
    resistance. Resistance is not in the
    physician’s control and varies with factors
    such as scar tissue formation. Cordless
    recharging is available with several manufacturers’
    systems.
    D. This is a specification set that is currently
    available. Aconstant voltage system is also
    now available with pulse widths up to
    1000 milliseconds.
    E. Maintaining both constant current and
    constant resistance would not be achievable
    because resistance is not a controllable
    factor. Voltage, current, and resistance vary
    according to Ohm’s law: voltage = current ×
    resistance.
    New batteries have reached the market
    including ones with constant voltage,
    pulse width of 1000 milliseconds, and battery
    size of about 22 cm3.
47
Q
  1. Which of the following is true?
    (A) Dorsal column pathways do not play a
    role in visceral pain and therefore there
    is no role of SCS for visceral pain
    (B) Pelvic pain has been demonstrated to
    consistently fail treatment with SCS
    (C) The midline dorsal column pathway has
    been the proposed target for stimulation
    for chronic visceral pain
    (D) Pelvic pain stimulation can best be
    achieved by first targeting the S2 foramen
    in a retrograde approach
    (E) There is no therapeutic potential for
    treatment of chronic visceral pelvic pain
    with SCS
A
  1. (C)
    A. Dorsal column pathways have been
    demonstrated to play a role in transmission
    of visceral pain.
    B. Case reports have been published showing
    successful treatment of pelvic pain with
    SCS. One such report was a case series of
    six patients with pelvic pain of multiple
    diagnoses all treated successfully with
    SCS. Diagnoses included vulvar vestibulitis,
    endometriosis, pelvic adhesions,
    uterovaginal prolapsed, and vulvodynia.
    C. Midline myelotomy may relieve visceral cancer
    pain. This is a deep pathway and therefore
    a tightly spaced lead which can drive the
    stimulation deeper would be advantageous
    for attempted SCS for visceral pain.
    D. The stimulation “sweet spot” for pelvic
    pain has been reported to be around T12.
    E. Case study evidence supports the role for
    SCS for chronic visceral pelvic pain.
    Further well-designed studies are needed.
48
Q
679. Which of the following is the best answer
regarding lead geometry and spacing?
(A) The goal of SCS in treatment of bilateral
lower extremity neuropathy pain is
most frequently to stimulate the dorsal
roots rather than the dorsal columns
(B) Tight lead spacing increases the ratio of
dorsal column to dorsal root stimulation
(C) Too much stimulation of the dorsal
columns results in motor side effects
(D) As the distance from the contact to the
spinal cord increases, stimulation
becomes more specific for the dorsal
columns as opposed to the dorsal
roots
(E) Rostrocaudal contact size (contact
length) is less important than lateral
contact size (contact width)
A
  1. (B)
    A. The dorsal columns contain the primary
    cutaneous afferents which are the usual
    targets. Stimulation of a nerve root will
    lead to segmental paresthesia and will not
    be likely to encompass the entire area of
    the bilateral lower extremity neuropathic
    pain.
    B. This is a correct statement and was supported
    by computer-modeled analysis.
    C. To the contrary, motor side effects usually
    indicates stimulation of dorsal roots rather
    than the dorsal column.
    D. This statement is incorrect because as the
    contact to spinal cord distance increases,
    stimulation becomes less specific and
    there is an increased chance of dorsal root
    stimulation.
    E. This is a false statement because fiber
    type preference is more sensitive to rostrocaudal
    contact size then to lateral contact
    size.
49
Q
  1. The gate control theory is one postulated mechanism
    of action for SCS. Which of the following
    is the most accurate application of SCS to this
    postulated mechanism of action?
    (A) Activation of large-diameter afferents
    thereby “closing the gate”
    (B) Activation of large-diameter afferents
    thereby “opening the gate”
    (C) Activation of small-diameter afferents
    thereby “closing the gate”
    (D) Activation of small-diameter afferents
    thereby “opening the gate”
    (E) Activation of both large- and smalldiameter
    afferents equally
A
  1. (A) Ronald Melzack and Patrick Wall published
    the landmark gate control theory in the
    journal Science in 1965. According to this theory
    as published in 1965, large and small fibers
    project to the substantia gelatinosa. The substantia
    gelatinosa exerts an inhibitory effect on
    afferent fibers. Large fibers increase the
    inhibitory effect, “close the gate,” and decrease
    the afferent pain signal. Small fibers decrease
    the inhibitory effect, “open the gate,” and
    increase the afferent pain signal.
    This gate control theory is commonly
    cited as the mechanism of action of SCS, but a
    2002 review concludes that other mechanisms
    must also play a role. [Oakley JC, Prager JP.
    Spinal cord stimulation: mechanisms of
    action. Spine. 2002;27(22):2574-2583.
    Melzack R, Wall PD. Pain Mechanisms: a
    new theory. A gate control system modulates
    sensory input from the skin before it evokes pain perception and response.
50
Q
  1. Which of the following is most accurate regarding
    indications for SCS?
    (A) Nociceptive pain is traditionally considered
    a better indication than neuropathic
    pain
    (B) Receptor mediated pain is traditionally
    considered a better indication than neurogenic
    pain
    (C) SCS tends to more effectively treat sympathetically
    mediated pain than pain of
    the somatic nervous system
    (D) Intractable angina is not effectively
    treated with SCS
    (E) Persisting neuropathic extremity pain
    following spinal surgery is a better indication
    than pain of CRPS
A
  1. (C)
    A. The opposite of the given statement would
    be more accurate (ie neuropathic pain is
    traditionally considered a better indication
    than nociceptive pain).
    B. This is a restatement of (A). The term
    “receptor mediated” is substituted for and
    synonymous with nociceptive. The term
    “neurogenic” is substituted for and synonymous
    with neuropathic.
    C. Multiple authors have described beneficial
    results of SCS for sympathetic-mediated
    pain [Stanton-Hicks M. Complex regional
    pain syndrome: manifestations and the role
    of neurostimulation in its management. J
    Pain Symptom Manage. 2006;31(suppl 4):
    S20-S24.
    Kumar K, Nath RK, Toth C. Spinal cord
    stimulation is effective in the management of
    reflex sympathetic dystrophy. Neurosurgery.
    1997;40(3):503-508.
    Harke H, Gretenkort P, Ladlef HU, et al.
    Spinal cord stimulation in sympathetically
    maintained complex regional pain syndrome
    type I with severe disability. A prospective
    clinical study. Eur J Pain. 2005;9(4):363-373.]
    D. This is a false statement as some consider
    intractable angina to be the pain most
    effectively treated with SCS, with up to
    90% effectiveness.
    E. Both persisting neuropathic pain of the
    extremity following spinal surgery and
    pain of CRPS are indications for SCS.
    However, persisting neuropathic extremity
    pain following spinal surgery is not a better
    indication. In fact, SCS is considered by
    some to be a more effective treatment of
    CRPS than persisting neuropathic pain of
    the extremity following spinal surgery.
51
Q
  1. Which of the following correctly arranges
    intraspinal elements from highest to lowest
    conductivity?
    (A) CSF, longitudinal white matter, gray
    matter, transverse white matter, dura
    (B) Longitudinal white matter, gray matter,
    CSF, transverse white matter, dura
    (C) Longitudinal white matter, transverse
    white matter, dura, gray matter, CSF
    (D) Gray matter, longitudinal white matter,
    transverse white matter, CSF, dura
    (E) Dura, transverse white matter, gray
    matter, longitudinal white matter, CSF
A
  1. (A) The conductivity of intraspinal elements has
    clinical significance. While some tissues have
    sufficient conductivity to allow stimulation to
    reach afferent fibers and initiate a depolarization,
    other tissues provide an insulation-like
    effect to protect visceral organs. One would not have to know the actual conductivities of
    intraspinal elements to answer this question.
52
Q
  1. Which of the following is the most accurate
    explanation why thoracic level cord stimulator
    leads do not commonly stimulate intrathoracic
    structures such as the heart?
    (A) Thoracic placement of SCS leads is contraindicated
    and is therefore not a clinically
    used technique
    (B) The CSF is highly conductive and therefore
    diverts the stimulation into a different
    direction
    (C) The stimulation is very specific for neural
    tissues rather than visceral tissues
    (D) The dura has a very low conductivity
    and therefore insulates visceral structures
    from stimulation
    (E) The vertebral bone has a very low conductivity
    and therefore insulates visceral
    structures from stimulation
A
  1. (E)
    A. Thoracic placement of SCS leads is very
    common. Contacts are often placed at the
    T8 level for instance for treatment of lower
    extremity pain.
    B. While it is true that CSF is highly conductive,
    it does not divert the stimulation
    away from thoracic structures.
    C. While it is true that various fibers have differing
    thresholds for recruitment, a negatively
    charged electrode (a cathode) will
    cause a neuron to become more electrically
    charged and depolarized, regardless of the
    tissue of origin.
    D. It is true that dura has a very low conductivity
    similar to vertebral bone. However,
    because the dura is so thin, it does not present
    significant resistance. This should also
    be instinctively false because if the dura
    insulated structures from stimulation, then
    it would not be possible to stimulate the
    neural structures of the spinal cord.
    E. This is a true statement. The conductivity
    of vertebral bone is very low compared to
    other intraspinal tissues.
53
Q
  1. Which of the following best describes the proposed
    mechanism of action of SCS?
    (A) There is evidence that during SCS large
    myelinated afferent fibers are activated
    in an antidromic manner
    (B) There is a measurable increase in
    endogenous opioids in response to SCS
    (C) Spinothalamic tract activation during
    SCS leads to an analgesic effect
    (D) SCS causes an inhibition of ascending
    and descending inhibitory pathways
    (E) SCS has no effect on abnormal A-β
    activity
A
  1. (A)
    A. Antidromic responses can be measured at
    the sural nerve during SCS. This was
    described in a 2002 review of SCS mechanisms
    and also demonstrated in 21 measurements
    in 16 patients in another study in
  2. [Oakley JC, Prager JP. Spinal cord
    stimulation: mechanisms of action. Spine.
    2002;27(22):2574-2583.
    Buonocore M, Bonezzi C, Barolet G.
    Neurophysiological evidence of antidromic
    activation of large myelinated fibers in
    lower limbs during spinal cord stimulation.
    Spine. 2008;33(4):E90-E93.]
    B. SCS efficacy is not reversed by naloxone
    and there is no relation of SCS to endogenous
    opioid levels.
    C. This would be a mechanism of algesic effect.
    In fact, one of the proposed mechanisms
    of action of SCS is spinothalamic tract
    inhibition.
    D. This would be a mechanism of algesic effect.
    In fact, one of the proposed mechanisms of
    action of SCS is activation of ascending and
    descending inhibitory pathways. On review
    of the mechanisms of action of SCS, one possible
    mechanism of action was cited as activation
    of supraspinal loops relayed by the
    brain stem or thalamocortical systems
    resulting in ascending and descending inhibition.
    [Oakley JC, Prager JP. Spinal cord
    stimulation: mechanisms of action. Spine.
    2002;27(22):2574-2583.]
    E. According to a 2002 review, the predominant
    effect of SCS is on abnormal activity in
    A-β neurons related to the perception of
    pain. [Oakley JC, Prager JP. Spinal cord
    stimulation: mechanisms of action. Spine.
    2002;27(22):2574-2583.]
54
Q
  1. Which of the following is true?
    (A) Phenol theoretically carries a higher risk
    for neuroma formation than alcohol
    (B) Radiofrequency ablation is particularly
    useful for field neurolysis
    (C) Phenol is a particularly useful neurolytic
    agent for localized targets
    (D) Alcohol is a particularly useful neurolytic
    agent because there is no pain
    upon injection
    (E) Phenol causes wallerian degeneration
A
  1. (A) Because phenol destroys the basal neurolemma,
    wallerian degeneration does not
    occur and there is a higher risk for neuroma
    formation. Lesion size is more difficult to precisely
    control with a liquid neurolytic injectate
    as compared to radiofrequency ablation in
    which the lesion size occurs in a known distance
    around the needle tip. On the other hand,
    when a field lesion is needed, a liquid neurolytic
    may be a more practical approach.
55
Q
686. Which of the following is most painless upon
delivery?
(A) Phenol
(B) Alcohol
(C) Radiofrequency
(D) Cryoanalgesia
(E) Cold knife excision of a nerve
A
  1. (A) Phenol is not painful upon injection

whereas the other listed techniques are painful.

56
Q
687. Which of the following neurolytic techniques is
most concerning for the side effect of
arrhythmia?
(A) Laser neurolysis
(B) Cryoanalgesia
(C) Radiofrequency
(D) Alcohol
(E) Phenol
A
  1. (E) Phenol is concerning for arrhythmias, seizure,
    destruction of Dacron grafts, vasospasm, and
    vascular proteins. Alcohol is more concerning
    for vasospasm than phenol. Caution when considering
    radiofrequency neurolysis includes
    interference with electrical implants. Risks of
    cryoneurolysis include frostbite to adjacent
    tissues.
57
Q
  1. Which of the following statements is the most
    accurate comparison of radiofrequency ablation
    and cryoablation?
    (A) Cryoanalgesia probes are generally
    smaller in diameter than the large-diameter
    probes used for radiofrequency
    procedures
    (B) One disadvantage of cryoanalgesia technique
    is the operator must support a
    heavier instrument while maintaining
    the probe tip in accurate position
    (C) The cryolesion and the radiofrequency
    lesion are similar in size
    (D) Cryoanalgesia and radiofrequency
    lesion techniques have equal precision
    capability
    (E) Cryoanalgesia is inferior to radiofrequency
    ablation because cryoanalgesia
    causes wallerian degeneration
A
  1. (B)
    A. Cryoanalgesia probes are generally larger
    in diameter than radiofrequency probes.
    Current cryoanalgesia probes range in size
    from 1.4 to 2 mm. The 1.4-mm cryoprobe is used with a 14- or 16-gauge catheter. A
    2-mm cryoprobe is inserted into a 12-
    gauge catheter. Radiofrequency procedures
    are commonly performed using a
    22-gauge needle. A22-gauge needle has an
    outside diameter of about 0.7 or 0.72 mm.
    B. The cryoanalgesia instrument may be cumbersome
    to support while simultaneously
    maintaining accurate needle-tip position.
    The smaller and lighter probes used with
    radiofrequency lesioning machines are less
    cumbersome to manage.
    C. The ice ball formed at the tip of the cryoprobe
    is larger in size than what can be
    obtained with radiofrequency lesions.
    D. Because of the smaller obtainable lesion
    size with the radiofrequency techniques, a
    more precise target lesion can be achieved.
    E. Both cryoanalgesia and radiofrequency
    techniques cause wallerian degeneration
    and therefore less risk for neuroma formation
    compared to phenol.
58
Q
  1. Which of the following is most accurate regarding
    the electric field generated at the tip of a
    radiofrequency electrode?
    (A) Flat conductors generate larger, stronger
    electric fields than round conductors
    (B) With round conductors, the charge density
    is directly proportional to the radius
    of the circle
    (C) The electric field around a radiofrequency
    cannula is more dense around
    the exposed shaft and becomes less
    dense at the tip
    (D) Voltage, current, and power are the
    three basic variables governing formation
    of heat surrounding a radiofrequency
    cannula tip
    (E) The heat lesion formed around the
    radiofrequency cannula is slightly pearshaped
    with the base of the pear around
    the proximal end of the active tip and less
    projection of the heat at the needle tip
A
  1. (E)
    A. Round conductors generate larger, stronger
    electric fields than flat conductors.
    B. With round conductors, the charge density
    is inversely proportional to the radius of
    the circle.
    C. The electric field around the exposed shaft
    of a radiofrequency cannula is less dense
    and becomes more dense at the tip.
    D. The three basic variables of electric current
    are voltage, current, and resistance. These
    are the three factors in Ohm’s law.
    E. Although the electric field is less dense
    around the shaft but more dense around
    the tip of the cannula, the shape of the heat
    lesion is different. The heat lesion is
    slightly larger around the proximal end of
    the active tip and smaller at the needle tip.
59
Q
  1. Which of the following is the most accurate
    statement regarding neuraxial neurolysis?
    (A) Phenol has significant proven benefit
    over alcohol
    (B) The technique is 100% efficacious
    (C) The average pain relief is less than
    6 months
    (D) Bladder paresis and motor weakness
    occurs in close to 100% of those treated
    with neuraxial neurolysis
    (E) Epidural neurolysis has a proven favorable
    risk to benefit ratio compared to
    subarachnoid neurolysis
A
  1. (C)
    A. While phenol may be useful for its hyperbaric
    property, there is no clear benefit versus
    alcohol.
    B. Excellent results are reported in 50% to
    75% of patients.
    C. The average duration of pain relief after
    neuraxial neurolysis has been reported at
    4 months.
    D. Bladder paresis and motor paresis occurs
    in approximately 5% of treated patients.
    Bowel paresis occurs in approximately 1%
    of treated patients.
    E. There is no evidence for greater efficacy or
    lower risk for epidural neurolysis compared
    to subarachnoid neurolysis.
60
Q
  1. While performing an intradiscal radiofrequency
    procedure using a posterior-oblique approach,
    the needle tip is advanced into the annulus
    fibrosus using fluoroscopic guidance. Impedance
    is noted. The needle tip is then advanced a little
    further. Adrop in impedance is noted. Which of
    the following is the most likely explanation?
    (A) Malfunction of radiofrequency machine
    (B) Needle-tip entry into CSF
    (C) Needle-tip entry into spinal cord
    (D) Needle-tip has dry blood on it
    (E) Needle-tip entry into nucleus pulposus
A
  1. (E) From the described approach, further
    advancement of the needle tip should either
    remain in annulus fibrosis or enter the next
    tissue layer, nucleus pulposus. CSF and spinal
    cord are not expected in the described trajectory.
61
Q
  1. Which of the following is appropriate safety
    consideration when performing a radiofrequency
    ablation procedure?
    (A) Motor stimulation is not needed if
    meticulous fluoroscopic technique is
    used
    (B) A radiofrequency probe should be the
    length of the cannula or shorter, but
    never longer than the cannula
    (C) The pain physician should always turn
    off a patient’s sensing pacemaker prior
    to a radiofrequency procedure
    (D) Complications during radiofrequency
    ablation are rare and need not be considered
    prior to the procedure
    (E) A SCS should be turned off prior to a
    radiofrequency procedure
A
  1. (E)
    A. Motor stimulation can detect and prevent
    unexpected improper heat lesioning. For
    example, a break in the insulation of the
    needle shaft can allow current to leak into
    unexpected tissues.
    B. The radiofrequency probe should extend
    to the tip of the cannula. Too short of a
    radiofrequency probe will result in temperature
    measurements that are lower than
    the actual tissue temperature. This is especially
    concerning as a radiofrequency unit
    with automatic temperature control would
    increase the output in this situation, leading
    to even higher tissue temperatures.
    C. It is usually best to consult a cardiologist
    prior to radiofrequency procedures when
    the patient has a pacemaker. If the pacemaker
    is a sensing pacemaker, then changing
    the setting to a fixed rate is suggested.
    D. It is best to prevent complications rather
    than treat complications.
    E. The SCS should be turned off prior to
    radiofrequency procedures.
62
Q
693. Coulomb per kilogram (C/kg) is
(A) the unit used to measure electrical
charge produced by x- or γ-radiation
similar to previous roentgen unit
(B) used to measure dose equivalent
(C) the daily radiation exposure per kilogram
of body weight
(D) the intensity of radiation
(E) used to measure the amount of radiation
absorbed
A
  1. (A) Coulomb per kilogram is used to measure
    electrical charge produced by x- or γ-radiation
    similar to previous roentgen unit in a standard
    volume of air by ionization. Sievert (Sv) is used
    to measure dose equivalent
63
Q
694. Gray (Gy) is used to measure
(A) yearly background exposure
(B) absorbed dose
(C) dose equivalent
(D) daily radiation exposure
(E) yearly radiation exposure
A
  1. (B) Gray (Gy) measures absorbed dose (energy
    deposited per unit mass). One gray is equal to
    1 J/kg.
64
Q
695. Maximum total permissible dose equivalents
(in mSv) for a year is
(A) 75 mSv
(B) 100 mSv
(C) 150 mSv
(D) 50 mSv
(E) 25 mSv
A
  1. (D) Individual doses may vary (eg, eye 12.5 mSv).
65
Q
696. How low should a clinician’s hourly radiation
exposure be?
(A) Less than 0.01 mSv/h
(B) Less than 0.05 mSv/h
(C) Less than 0.15 mSv/h
(D) As low as reasonably achievable
(E) Less than 0.25 mSv/h
A
  1. (D) As low as reasonably achievable is also
    known as ALARA (As low as reasonably
    achievable).
66
Q
697. Most operator exposure during fluoroscopically
guided blocks is when
(A) the lateral views are taken
(B) the x-ray tube is above the patient
(C) the patient is obese
(D) the anteroposterior views are taken
(E) none of the above
A
  1. (B) The x-ray tube above the patient provides
    most operator exposure because the scattered
    beam is greater at the entrance site of the skin
    compared to exit site.
67
Q
  1. The intensity of scattered beam is greater at the
    radiation entrance on the skin than exit site
    (A) 3 times
    (B) 10 times
    (C) 30 times
    (D) 985 times
    (E) 1000 times
A
  1. (D) As the intensity of scattered beam is greater
    at the radiation entrance on the skin than exit
    site the radiation exposure to the operator is
    significantly increased when the x-ray tube is
    above the patient.
68
Q
  1. Average patient radiation exposure dose
    during pain procedures is
    (A) 10 times less than during angiography
    (B) same as during angiography
    (C) 10 times more than during angiography
    (D) less than computed tomographic (CT)
    scanning
    (E) 20 times more than during angiography
A
  1. (C) The patient radiation doses of angiography
    are on the other hand 10 times higher than gastrointestinal
    fluoroscopy and CT imaging.
69
Q
700. Radiation dose to the patients and medical personnel
can be reduced by
(A) decreasing the distance between the
image intensifier and the patient
(B) increasing the distance between the
image intensifier and the patient
(C) using continuous fluoroscopy
(D) oblique views
(E) none of the above
A
  1. (A) Oblique views can also increase the radiation

to the patients and operators.

70
Q
701. Personnel radiation protection can be achieved
by
(A) lead aprons
(B) glasses
(C) increased distance from the x-ray
(D) all of the above
(E) none of the above
A
  1. (D) Lead aprons contain equivalent of 0.5 mm
    of lead and can reduce the radiation exposure
    by 90% from scatter.
71
Q
702. Lead aprons should be always hung:
(A) So that space is saved
(B) As the lead can be broken if folded
(C) They can be safely folded as well
(D) So they can be conveniently available
(E) None of the above
A
  1. (B) Broken lead in aprons can provide suboptimal

radiation protection.

72
Q
  1. A patient with severe spasticity is a candidate
    for an intrathecal baclofen pump. He and his
    family have heard that “these pumps get
    infected.” How do you respond?
    (1) Device-related infection is the most
    common, potentially reducible, serious
    adverse event associated with intrathecal
    pumps
    (2) The majority of infections occur at the
    lumbar site
    (3) Management of infections associated
    with drug-delivery systems usually
    involves the administration of antibiotics
    and explantation of the device
    (4) The chances of the pump getting
    infected are minimal and the family
    should only focus on the benefits that
    the device provides
A
  1. (B) The diagnosis of an implantable devicerelated
    surgical-site infection is definitively
    made by identification or culture of microorganisms
    (most commonly bacteria) or both on
    specimens from a clinically suspected surgical
    wound or implant site. Signs of wound infection
    include fever, erythema, edema, pain,
    wound exudates, poor healing, or skin erosion
    at the implant site. Meningismus indicates CSF
    involvement.
  2. Infections related to the implantation of a SCS
    or an intrathecal drug-delivery system is the
    most common, potentially reducible, serious
    adverse events associated with these devices.
  3. In the comparison of drug-delivery devicerelated
    infections in multicenter studies the
    pump pocket was the site of infection
    between 57.1% and 80% of the time, the
    lumbar site was the infection location
    between 13% and 33% of the time, and
    meningitis was the infection between 10%
    and 14.3% of the time.
  4. Management of infections associated with
    drug-delivery and SCS systems typically
    involves administration of antibiotics and
    explantation of the devices.
  5. You should always worry about potential
    complications.
    The infection rates, based on the number of
    infections that occurred and the number of
    patients that were evaluated have varied from
    2.5% to 9.0% of implanted patients. The highest
    infection rate (9%), occurred in the 10-mL
    SynchroMed pump that was used in pediatric
    patients with spasticity of cerebral origin
    (n = 100), predominantly spastic cerebral palsy.
    The lowest infection rate, (2.5%), occurred in
    the group that received intrathecal recombinant
    methionyl human brain-derived neurotrophic
    factor (BDNF) to treat amyotrophic
    lateral sclerosis. 36 infections in 35 patients
    were described in a total of 700 patients (5%
    overall infection rate).
73
Q
  1. When trialing intrathecal medication and placing
    intrathecal pumps, which of the following
    is considered good technique?
    (1) Antibiotics are given during the course
    of the trial, and for 7 to 10 days after
    permanent implant
    (2) If the entry point is above L2, the
    patient should be conversant, and the
    angle of entry should be as shallow as
    possible
    (3) Placing the patient in the lateral decubitus
    position with the hips flexed, and
    the knees bent
    (4) Electrocautery is now considered the
    gold standard for controlling bleeding
A
  1. (A)
  2. The most common antibiotics used are a
    third-generation cephalosporin or vancomycin.
    Intraoperatively, many physicians
    irrigate the wound with antibiotic
    solution. Adjustments to antibiotic regimens
    should be made based on the most
    common pathogens seen in the community
    and medical center.
  3. In most instances the needle entry point
    into the intrathecal space is below L2.
    Sometimes, although rare, the entry point is
    at the level of the cord. If the entry point is
    above L2, the patient should be communicating
    with the physicians and nurses, and
    the angle of entry should be as small as
    possible. If any paresthesia is experienced,
    the needle should be removed and repositioned. Once the catheter is properly
    positioned, a purse-string suture should be
    fashioned to secure the tissue around the
    catheter. Then, an anchor should be used to
    fasten the catheter to fascia. Given recent
    studies on inflammatory masses at catheter
    tips, whether the distal end of the catheter
    should be placed near the supposed pain
    generator or not is still up for debate.
  4. While the patient may be positioned prone
    for catheter placement, placing them in the
    lateral decubitus position precludes having
    to reposition them for pocket creation. The
    usual site for pump placement is the lateral
    anterior abdominal wall at the level of the
    umbilicus. The pump should be anchored
    in a manner to prevent flipping.
  5. The physician should meticulously obtain
    proper hemostasis during the case. Small
    venous and arterial bleeders can be recognized
    by retracting the wound after antibiotic
    irrigation. Numerous techniques exist
    to obtain hemostasis:
    • Simple pressure
    • Sponges soaked in 3% hydrogen peroxide
    solution may be packed into the
    wound for 3 to 5 minutes (may be very
    helpful with small vessels)
    • Electrocautery for more pronounced
    bleeding [Note: overheating tissue can
    cause trauma or seroma formation,
    which can lead to delayed healing, dehiscence,
    or infection of the wound]
    • Suturing a vessel is still the gold standard
    A large sterile pressure dressing should be
    applied over the wound plus/minus an abdominal
    binder to reduce the risk of seroma formation
    and bleeding. Antibiotic ointment is also frequently
    used immediately over the incision; it
    may help in preventing the spread of infection.
    When considering dressing changes, the
    physician should be judicious—they can take
    place daily or only if the dressing is excessively
    saturated.
74
Q
  1. Which of the following is (are) disease state(s)
    that are amenable to treatment by intrathecal
    drug-delivery system?
    (1) Intractable spasticity related to cerebral
    palsy and spinal cord injuries
    (2) Interstitial cystitis
    (3) Cancer-related syndromes
    (4) Rheumatoid arthritis
A
  1. (E) In the early 1980s intrathecal drug-delivery
    was initiated for the treatment of intractable
    spasticity related to cerebral palsy and spinal
    cord injuries. This therapy eventually evolved
    to use in implacable cancer pain. Intrathecal
    preservative-free baclofen and morphine are
    FDAapproved for the treatment of moderate to
    severe spasticity and moderate to severe pain,
    respectively. A study in oncology patients
    showed a major improvement using intrathecal
    medication delivery in cancer pain versus thorough
    medical management in the areas of
    tiredness, level of consciousness, and survival.
    [Smith TJ, Staats PS, Deer T et al. Randomized
    clinical trial of an implantable drug delivery
    system compared with comprehensive medical
    management for refractory cancer pain:
    impact on pain, drug-related toxicity, and survival.
    J Cli. 2002;20(19):4040-4049.]
    Other disease states found to be responsive to
    intrathecal drug-delivery systems are
    • Spinal stenosis
    • Radiculitis
    • Compression fractures
    • Spondylosis
    • Spondylolisthesis
    • Foraminal stenosis
    • Arachnoiditis
    • Syrinx
    • Ankylosing spondylitis
    • Spinal cord trauma
    • Spinal infarction
    • Paraplegia
    • Cauda equina syndrome
    • Peripheral neuropathy
    • Phantom limb pain
    • Rheumatoid arthritis
    • Radiation neuritis
    • Postherpetic neuralgia
    • Postthoracotomy syndrome
    • Interstitial cystitis
    • Chronic pain of the abdomen and pelvis
75
Q
  1. A 56-year-old female who had an intrathecal
    pump placed secondary to metastatic renal cell
    carcinoma is having pain equivalent to a 6 on the visual analog scale (VAS). What is the
    proper titration regimen?
    (1) Increase dose 10% to 25% over 3 to 4 days
    (2) Increase dose 25% to 50% daily
    (3) Hourly rates should be adjusted 35% to
    50% twice daily until pain relief is
    achieved
    (4) A therapeutic bolus should be considered
A
  1. (C) Patients with a VAS pain scale of 7 to 10 may
    necessitate inpatient/hospice care for pain treatment.
    For those who wish to remain in a home
    environment, a 50% to 100% increase in their
    medication dose may be in order. Therapeutic
    boluses should be administered to an end point of pain relief, as well as daily medication adjustments
    to the same end point. Significant, abrupt
    increase in medication may cause severe side
    effects, and physicians should be available in
    the first 12 hours following the modification, to
    manage potential complications.
76
Q
  1. A 52-year-old female with pancreatic cancer
    and her family are trying to decide between
    continued medical management for pain versus
    an intrathecal drug-delivery system. Believing
    that this patient would most benefit from an
    intrathecal pump, you tell them that studies
    have shown that
    (1) overall toxicity is better with intrathecal
    pumps
    (2) pain relief is better with intrathecal pumps
    (3) intrathecal pumps improve fatigue and
    level of consciousness in patients versus
    medical management
    (4) there is a trend to increased survival in
    patients who have intrathecal pumps
    versus those continuing with medical
    management
A
  1. (E) A multicenter, randomized, prospective
    study compared intrathecal drug delivery to
    comprehensive medical management. The
    results showed a statistically significant advantage
    of intrathecal pumps on
    • Overall toxicity
    • Pain relief
    • Fatigue and level of consciousness
    • Improved survivability
    The study hinted that more patients with
    moderate to severe cancer pain should be considered
    for intrathecal pumps. [Smith TJ,
    Staats PS, Deer T et al. Randomized clinical
    trial of an implantable drug delivery system
    compared with comprehensive medical management
    for refractory cancer pain: impact on
    pain, drug-related toxicity, and survival. J
    Clin. 2002;20(19):4040-4049.]
77
Q
  1. Third occipital nerve
    (1) innervates C2-3 facet joint
    (2) curves around superior articular process
    of the C2 vertebrae
    (3) curves around superior articular process
    of the C3 vertebrae
    (4) innervates C3-4 facet joint
A
  1. (B) The third occipital headache is caused by
    third occipital neuralgia. The TON innervates
    the C2-3 zygapophysial joint and curves
    around the superior articular process of the C3
    vertebral body. Among patients with whiplash
    injuries, third occipital headache is common,
    with a prevalence of 27%.
78
Q
  1. For the peripheral stimulation of the occipital
    nerve
    (1) the electrode should be parallel to the
    occipital nerve in the occipital area of
    the scull
    (2) only a “paddle-” type electrode should
    be used
    (3) the entry site of the introducer needle
    should be at T1-T2 level
    (4) the electrode should be placed subcutaneously
    at the C1-C2 level
A
  1. (D) The occipital nerve stimulator is a useful
    tool in managing occipital neuralgia. Although
    paddle electrodes are not necessary they may
    provide better coverage than the regular
    electrode.
79
Q
  1. T2 and T3 sympathetic block
    (1) is used for treatment of upper extremity
    complex regional pain syndrome (CRPS)
    (2) will help by denervating the Kuntz
    nerves
    (3) can lead to pneumothorax
    (4) should avoid radiofrequency of T2 and
    T3 sympathetic ganglia
A
  1. (A) T2 and T3 sympathetic blocks are a useful
    tool in conjunction with stellate ganglion block
    for upper extremity CRPS. By blocking them,
    Kuntz nerves will be blocked that bypass the
    stellate ganglion. RF denervation of these
    nerves may lead to prolonged pain relief.
80
Q
  1. Vertebroplasty may be indicated for
    (1) multiple myeloma
    (2) chronic compression fractures of
    vertebral body
    (3) osteolytic metastatic tumors
    (4) facet arthropathy
A
  1. (A) Vertebroplasty is best used for acute vertebral
    fracture where bone cement is percutaneously injected into a fractured vertebra in order to
    stabilize it. Alternatively, kyphoplasty involves
    placement of a balloon into a collapsed vertebra,
    followed by injection of bone cement to
    stabilize the fracture. It is not clear if one procedure
    has an advantage over the other. Both
    procedures may obtain almost immediate pain
    relief. And they are indicated for painful compression
    fractures because of osteoporosis and
    metastatic tumors.
81
Q
  1. Complications from vertebroplasty include
    (1) pulmonary embolus
    (2) intradiscal leak of polymethyl
    methacrylate
    (3) paraplegia
    (4) psoas muscle leak of polymethyl
    methacrylate and femoral neuropathy
A
  1. (E) Complications from vertebroplasty can be
    serious. Intravascular injection of polymethyl
    methacrylate can lead to pulmonary embolus
    and spinal cord damage and leak into intrathecal
    space can cause spinal cord injury. Lumbar
    procedures may lead to leak into psoas muscle
    and femoral neuropathy.
82
Q
713. Which of the following is (are) correct with
regards to piriformis muscle injection?
(1) Should be done at medial part of a
muscle
(2) Botox can be used
(3) Nerve stimulation may aid in muscle
location
(4) Identification of the muscle can be done
through rectal examination
A
  1. (E) Piriformis injection should be done in the
    medial part of a muscle since the lateral part
    contains more ligaments. If injection of local
    anesthetics and steroids provides short-term
    pain relief only, the injection of botulinum toxin
    type Amay provide longer pain relief. The use
    of nerve stimulator, fluoroscopy, and contrast
    administration may help to assure proper
    needle placement. Tenderness over the piriformis
    muscle, positive Pace and Freiberg signs
    and rectal examination can be helpful in examining
    the piriformis muscle
83
Q
  1. SI joint pain
    (1) is transmitted by the S1-S4 levels of
    spinal nerves
    (2) has been treated by the SI joint fusion
    (3) can be relieved by blind steroid
    injections
    (4) is transmitted by L4 medial branch, L5
    dorsal ramus, and S1-3 lateral branches
A
  1. (D)
  2. The innervation of the SI joint is from L4
    medial branch, L5 dorsal ramus, S1, S2, and
    S3 lateral branches. Some authors also state
    that the L3 medial branch may be involved.
  3. SI joint fusion is used only in cases where
    serious anatomical problems (eg, fracture)
    are present in addition to pain.
  4. SI joint injection should be done under fluoroscopic
    guidance to assure accuracy of
    needle placement.
84
Q
  1. Celiac plexus block can be performed by
    (1) anterior approach
    (2) retrocrural approach
    (3) anterocrural approach
    (4) lateral approach
A
  1. (B)
  2. Anterior approach was initial approach
    described for blocking celiac plexus. Its
    advantage is that patient can be in more
    comfortable, supine position.
  3. Although the retrocrural block may partially
    block the nerve supply to the celiac plexus
    actually blocks the splanchnic plexus.
  4. Anterocrural approach is done with patient
    in prone position using one or two needles.
    Transaortic and transdiscal variation of this
    approach has been published as well.
  5. Lateral approach is not used for celiac
    plexus block.
85
Q
  1. Ganglion impar block
    (1) is indicated for testicular pain
    (2) is indicated for sympathetically maintained
    pain in perineal area
    (3) is best performed by anococcygeal
    approach
    (4) can be complicated by perforation of
    rectum
A
  1. (C)
  2. Testicular pain is treated by ilioinguinal
    block or lumbar sympathetic block.
  3. Ganglion impar is the most caudal sympathetic
    ganglion.
  4. The ganglion impar is located at the level of
    the sacrococcygeal junction that marks the termination
    of the paired paravertebral sympathetic
    chains. Initial approach described was
    through anococcygeal ligament. However, the
    trans-sacrococcygeal approach seems much
    safer way to perform this procedure.
  5. Perforation of rectum may occur in particular
    if anococcygeal approach is used.
86
Q
  1. With cervical interlaminar epidural steroid
    injection
    (1) loss of resistance technique can be inaccurate
    in up to 50% cases
    (2) unilateral medication spread can be
    achieved in 50% cases
    (3) contrast spread should be checked in
    lateral views
    (4) transforaminal approach is safer than
    interlaminar
A
  1. (A)
  2. As a result of discontinuous ligamentum
    flavum the loss of resistance is often inaccurate
    in cervical levels and more often in
    comparison to lumbar levels (30%).
  3. The fluoroscopic guidance should be used
    and medication should be deposited ipsilateral
    to the pathology.
  4. Final needle advancement and contrast
    spread should be first checked in lateral fluoroscopic
    views.
  5. Transforaminal approach (most likely
    because of intravascular particulate steroid
    uptake) can lead to serious complications
    such as spinal cord infarction, quadriplegia,
    and death.
87
Q
  1. Which of the following includes complication(
    s) of intrathecal pump?
    (1) Granuloma formation
    (2) CSF leak
    (3) Pump rotation
    (4) Hormonal imbalance
A
  1. (E)
  2. Granuloma formation can occur at the tip
    of the intrathecal catheter and can lead to
    serious complications including spinal cord
    injury.
  3. CSF leak is a relatively common complication
    of intrathecal pump placement.
  4. Pump rotation can cause kinking of the
    catheter and symptoms of increased pain
    and withdrawal.
  5. Intrathecal opioids can lead to serious hormonal
    changes including weight gain.
88
Q
719. In relation to increased pain in patient with
intrathecal opioid delivery which of the following
is (are) true?
(1) It can mean progression of disease
(2) Catheter kink should be considered
(3) One should look for withdrawal
symptoms
(4) Opioids should be increased first
A
  1. (A) Increased pain, in particular with withdrawal
    symptoms should be considered as a
    pump failure and treated promptly.
89
Q
  1. Which of the following is (are) drug(s) used in decompressive neuroplasty?
    (1) Hyaluronidase
    (2) Hypertonic saline
    (3) Steroids
    (4) Local anesthetics
A
  1. (E) Combination of hyaluronidase and hypertonic
    saline seems to increase the duration of
    procedure effect. Intrathecal injection of hypertonic
    saline can lead to serious complications
    and should be performed carefully.
90
Q
  1. SCS been used for the treatment of
    (1) interstitial cystitis
    (2) postlaminectomy syndrome
    (3) CRPS
    (4) sympathetically mediated pain
A
  1. (E) Traditional indications for SCS include postlaminectomy
    syndrome and CRPS. Indications
    have been expanding. Intestinal cystitis is now
    a commonly accepted indication. SCS is an
    accepted method for effective treatment of
    sympathetically mediated pain.
91
Q
  1. Spinal cord stimulation
    (1) should be used early in the course of the
    postherpetic neuralgia pain syndrome
    (2) has been found efficacious for the failed
    back surgery syndrome
    (3) has been used for peripheral vascular
    disease and ischemic disease
    (4) has a proven and elucidated mechanism
    of action
A
  1. (A) According to a review in 2008, SCS should
    be considered early in the course of postherpetic
    neuralgia and peripheral nerve stimulation
    should be considered if SCS fails. SCS is
    about 50% effective for failed back surgery syndrome
    and more so effective for peripheral vascular
    disease and ischemic disease. Although
    the gate control theory is a commonly cited
    mechanism of action for SCS, literature reflects
    that this one mechanism alone is not sufficient
    to explain the mechanism of action. According
    to a 2002 review article, there are 10 proposed
    mechanisms of action found in literature.
    [Oakley JC, Prager JP. Spinal cord stimulation:
    mechanisms of action. Spine. 2002; 27(22):
    2574-2583.]
92
Q
  1. The transverse tripolar SCS arrangement
    (1) involves a central anode surrounded by
    cathodes
    (2) contributes maximum dorsal column
    stimulation with minimal dorsal root
    stimulation
    (3) is most frequently used to improve
    stimulation of the feet
    (4) usually involves an octapolar spinal
    midline lead and two adjacent
    quadripolar leads
A
  1. (C) Transverse tripolar SCS on involves a central
    cathode surrounded by anodes. This is proposed
    to drive current deeper and thus
    stimulate fibers innervating the back. Therefore
    is it used to cover back pain, not foot pain.
    Statement (4) is also correct as most current
    SCS systems allow up to a total of 16 leads.
93
Q
  1. Which of the following is (are) true for SCS for
    the indication of angina pectoris?
    (1) Improves exercise capacity
    (2) Probably only helps for a year and then
    the stimulator should be removed
    (3) In addition to providing antianginal
    effects it also provides a reduction in
    ischemia
    (4) Is contraindicated because it masks significant
    ischemic events
A
  1. (B) In a 2006 review article SCS was concluded
    to increase exercise capacity as well as decrease
    use of short-acting nitrates and improve quality
    of life. The review also found that at 5 years
    60% of patients still had beneficial effects.
    Exercise stress testing and electrocardiogram
    (ECG) monitoring evidence showed reduced
    ischemia in addition to the antianginal effects.
    Pain perception remains intact and patients
    were still able to detect significant ischemic
    events. .]
94
Q
725. Which of the following is (are) the risk(s) associated
with SCS?
(1) Epidural hematoma
(2) Spinal cord injury
(3) Implanted pulse generator failure
(4) Electromechanical failure of lead or
extension cable
A
  1. (E) All listed factors are risks of SCS. Other
    risks include nerve injury, dural puncture,
    infection, and electrode migration.
95
Q
  1. Which of the following is (are) true regarding
    SCS for visceral pain?
    (1) SCS suppresses visceral response to
    colon distention in animal models
    (2) SCS is a first-line treatment for visceral
    pain
    (3) Case studies have indicated SCS may be
    helpful for visceral pain but at this time
    there is a lack of supporting randomized
    controlled trials
    (4) A good lead placement for stimulation
    of chronic pancreatitis would logically
    be around T12 or L1
A
  1. (B) In animal models, SCS has been shown to
    suppress visceral responses. There have been
    multiple case reports of SCS being used successfully
    for visceral pain; however, current
    practice parameters do not address treatment
    of such pain. Since the pancreas is innervated
    by spinal segments around T5-T11, a lead
    placement would be much too low of a logical
    starting place. One case study reported placing
    the lead at T6 resulting in appropriate stimulation
    for treatment of chronic pancreatitis.
96
Q
  1. Which of the following is (are) the best
    answer(s) regarding lead spacing and electrical fields created by a dual-lead stimulation system as pictured?
    (1) With larger distances between anodes
    and cathodes, the electric field tends to
    form a sphere
    (2) With tighter lead spacing and smaller
    distances between anodes and cathodes,
    the electric field is pulled towards the
    anode
    (3) Tight lead spacing increases the ratio of
    dorsal column to dorsal root stimulation
    (4) The anode is the positive contact and
    the cathode is the negative contact
A
  1. (E) Anode is the correct designation for a positive
    contact and cathode is the correct designation
    for a negative contact. With a dual-lead
    system as pictured, the electric field would be
    pulled toward the anode if lead spacing were
    tight. With larger lead spacing, the electric field
    would tend to be more spherical and positioned
    around the cathode. Tight lead spacing
    increases the dorsal column to dorsal root stimulation
    ratio because the less spherical electric
    field would stimulate less laterally and therefore
    would have less stimulation in the areas of
    the nerve roots.
97
Q
728. Which of the following should be considered
when selecting patients for SCS?
(1) Disease pathology
(2) Untreated drug addiction
(3) Patient comorbidities
(4) Physician’s monthly case quota
A
  1. (A) According to a review article on selection
    criteria for SCS, selection criteria may relate to
    the patient’s disease state or to other important
    patient characteristics. Current randomized
    controlled trials or prospective trials
    support efficacy of SCS for certain disease
    states such as failed back surgery syndrome,
    CRPS, axial back pain, postherpetic neuralgia,
    neuropathy, and pelvic pain. Current case
    report evidence exists for SCS in the treatment
    of ischemic limb pain, and visceral pain.
    Anginal pain has also been investigated.
    Patient characteristics of concern include systemic
    disease such as diabetes, immunocompromised,
    degree of stenosis especially for
    cervical placed leads, anticoagulation, psychologic
    comorbidities, unrealistic outcome expectations,
    and, untreated drug addictions.
    [Oakley JC. Spinal cord stimulation: patient
    selection, technique, and outcomes.
98
Q
  1. Which of the following is (are) considered indication(
    s) for SCS?
    (1) Phantom limb pain
    (2) Spinal cord injury pain
    (3) Intractable abdominal or visceral pain
    (4) Neurogenic thoracic outlet syndrome
A
  1. (E) The indications for SCS are expanding. All of the listed etiologies are now considered indications for SCS.
99
Q
  1. Which of the following is (are) true regarding
    the history of electrical stimulation for the treatment
    of pain?
    (1) Electrical stimulation for the treatment
    of pain dates back to the first century ad
    when electrical fish were documented to
    be used in the treatment of gout
    (2) Implantable SCS were used for treatment
    of pain for a decade prior to the
    published gate control theory of pain
    (3) Early stimulation case reports were of
    peripheral nerve stimulation; later
    emphasis turned toward SCS
    (4) Psychiatric and/or psychologic screening
    evaluation prior to implants was a
    new idea imposed upon physicians by
    health maintenance organizations in the
    1990s
A
  1. (B)
  2. Scribonius Largus documented application
    of the live black torpedo fish under the foot
    for treatment of the pain of gout. “For any
    type of gout a live black torpedo should, when the
    pain begins, be placed under the feet. The patient
    must stand on a moist shore washed by the sea
    and he should stay like this until his whole foot
    and leg up to the knee is numb. This takes away
    present pain and prevents pain from coming on if
    it has not already arisen. In this way Anteros, a
    freedman of Tiberius, was cured.”
  3. The gate control theory of pain was published
    in 1965. This laid the theoretical foundation
    for electrical stimulation for pain.
    The first modern case report of electrical
    stimulators for treatment of pain was 2 years
    later. It described eight cases in which sensory
    nerves or roots were stimulated resulting
    in relief of pain. [Melzack R, Wall PD.
    Mechanisms: a new theory. A gate control
    system modulates sensory input from the
    skin before it evokes pain perception and
    response. Science. 1965;150(3699).
    Wall PD, Sweet WH. Temporary abolition
    of pain in man. Science. 1967;155(758):108-109.]
  4. In the peripheral nerves, motor and sensory
    fibers are within closer vicinity. The window of amplitude available to provide analgesia
    without excessive motor stimulation is
    therefore much less than in the spinal cord
    where sensory and motor fibers run in more
    discrete and separate pathways. This
    played a role in switching emphasis from
    peripheral nerve stimulation toward SCS.
  5. The first documented cases of modern day
    stimulation for pain was a case series of eight
    patients published in 1967. This case series
    reported three of the eight patients received
    psychiatric evaluation prior to the procedures.
    The psychiatric/psychologic evaluation
    gives the patient an opportunity to belay
    anxiety, ask questions, address body image
    issues, and communicate expectations
100
Q
  1. Which of the following is (are) accurate statement(
    s) regarding neuromodulation of the
    sacral nerves?
    (1) Sacral neuromodulation is not effective
    for idiopathic urinary frequency
    (2) Both percutaneous and surgical lead
    placement techniques have been
    described
    (3) Must be performed by a surgeon
    because only a surgical technique is
    available
    (4) Urgency and urge incontinence are
    indications
A
  1. (C) Sacral neuromodulation has been reported
    as effective for idiopathic urinary frequency,
    urgency, and urge incontinence. Both percutaneous
    and surgical sacral neuromodulation
    procedures have been described. Percutaneous
    techniques include (1) placement of a lead
    directly into the sacral nerve root foramen and
    (2) a percutaneous retrograde approach.
    Surgical techniques include (1) performing a
    sacral laminectomy and attaching the electrodes
    directly to the sacral nerve roots and
    (2) dissection to sacral periosteum where a
    plastic anchor is used to affix a transforaminal
    lead. Techniques that are limited to one lead
    placement may have limitations in terms of
    efficacy for certain indications. While a single
    lead has been generally efficacious for voiding
    dysfunctions, chronic neuropathic pain syndromes
    may benefit from a more extensive field
    of neuromodulation with additional electrodes
101
Q
  1. Which of the following is (are) true regarding
    radiofrequency procedures?
    (1) Pulsed radiofrequency lesioning temperature
    goal is generally around 42°C
    to 43°C
    (2) Prior to application of the radiofrequency
    lesion, sensory testing should be
    applied at 2 Hz
    (3) The standard pulsed radiofrequency
    lesion is 500,000 Hz for 20 milliseconds
    pulses once every 0.5 second for 90 to
    240 seconds
    (4) Prior to application of the radiofrequency
    lesion, motor testing should be
    applied at 50 Hz
A
  1. (B)
  2. Temperatures above 45°C cause irreversible
    neural tissue damage. If temperatures of
    45°C are reached, then the voltage should
    be decreased to compensate.
  3. Sensory testing is applied at 50 Hz.
  4. The pulsed technique allows tissues to
    cool somewhat between cycles. A voltage of 45 V generally corresponds to a 43°C
    tip temperature. If the tip temperature
    exceeds 43°C, then the voltage should be
    reduced.
  5. Motor testing is applied at 2 Hz.
102
Q
  1. Which of the following element(s) is (are) necessary
    to complete a radiofrequency circuit?
    (1) The radiofrequency generator
    (2) Insulated needle cannula with radiofrequency
    probe
    (3) Dispersive electrode (grounding pad)
    (4) The patient
A
  1. (E) All the options mentioned in the question
    are required elements to complete the circuit.
    The current goes from the probe tip, through
    the patient and to the grounding pad which
    carries the current back to the radiofrequency
    generator.
103
Q
734. Which of the following is (are) the possible
mechanism(s) of action of radiofrequency
ablation?
(1) Vascular injury causing endoneural
edema
(2) Formation of a static electric field
(3) Lipid extraction with protein precipitation
(4) Generation of heat
A
  1. (C) Formation of a static electric field and generation
    of heat are two phenonemon that have
    been postulated as possible mechanisms of
    action of radiofrequency ablation. The mechanism
    of action of cryoablation involves vascular
    injury which causes severe endoneural
    edema. The mechanism of action of alcohol
    ablative techniques is lipid extraction with protein
    precipitation.
104
Q
  1. Which of the following is (are) the most accurate
    answer(s) regarding radiofrequency treatment
    of the SI joint?
    (1) Evidence is strong for efficacy of
    radiofrequency ablation techniques for
    SI joint pain
    (2) The universally accepted screening protocol
    prior to SI joint injection involves
    SI tenderness, positive SI provocative
    maneuvers, and two positive local anesthetic–
    only SI joint injection procedures
    (3) There is no evidence for the role of
    pulsed radiofrequency treatment of SI
    joint pain
    (4) Radiofrequency treatment of sacral lateral
    branches have been proposed for
    efficacious treatment of SI joint pain
A
  1. (D)
  2. Although there are several studies looking
    at radiofrequency neuroablation for the SI
    joint, according to a recent systematic
    review evidence is still limited for its therapeutic
    value.
  3. Although there are guidelines such as those
    posed by International Association for the
    Study of Pain (IASP), evidence and universal
    acceptance are still lacking. Some studies
    have refuted SI provocative maneuvers
    as predictive at all while others found that
    three of five positive provocative maneuvers
    provide predictive value. The role of
    adding steroids to diagnostic SI injections is
    similarly debated.
  4. Pulsed radiofrequency treatment was given
    to 22 patients with injection evidence of SI
    pain. Sixteen patients (73.9%) had 50% or
    better relief for more than 3 months.
  5. In a 2003 pilot study, 8 of 9 patients experienced
    50% or better pain relief after
    radiofrequency lesioning at L4 primary
    dorsal rami and S1-S3 lateral branches.
    Relief persisted at 9 month follow-up.
105
Q
  1. Purported advantages of percutaneous radiofrequency
    lesions over other neuroablative techniques
    include
    (1) predictable and quantifiable lesions
    (2) avoids the extensive soft tissue damage
    of surgical techniques
    (3) ability to confirm needle-tip proximity
    to sensory and motor nerves
    (4) ability to cover a wide field
A
  1. (A) Other advantages of radiofrequency lesions
    include avoids sticking and charring (in contrast
    to direct current electrical lesions), no gas formation
    (in contrast to direct current electrical
    lesions), impedance monitoring, and amenable
    to fluoroscopic and CT guidance. Ability to identify
    needle-tip proximity to motor and sensory
    nerves is a characteristic of radiofrequency procedures,
    although cryoanalgesia probes are also
    available with built-in nerve stimulators. Ability
    to cover a wide field is not an advantage of percutaneous
    radiofrequency lesion. Percutaneous
    radiofrequency techniques deliver relatively
    smaller, more defined treatment areas and therefore
    a great deal of lesions would be needed in
    order to cover a wide field target.
106
Q
  1. Which of the following is (are) accurate regarding
    the history of ablation techniques?
    (1) Norman Shealy reported the first use of
    radiofrequency lesioning for treatment
    of facet pain in 1975
    (2) The first report of percutaneous
    radiofrequency lesioning for treatment
    of pain came in 1981
    (3) Slappendel reported the first clinical use
    of pulsed radiofrequency lesioning in
    1997
    (4) Although a modern cryoneuroablation
    device was developed and refined in the
    1960s, the application for pain management
    gained popularity in the 1980s
A
  1. (E) These are all accurate historical events as
    described and cited in current literature
    reviews. Pulsed radiofrequency techniques
    have received growing interest since 1997,
    when treatment of the cervical spinal dorsal
    root ganglions with pulsed radiofrequency
    suggested efficacy and safety. In 1961, Cooper
    described a device which used liquid nitrogen
    in a hollow tube that was insulated at the tip
    and achieved temperatures as low as −190°C.
    He published his description in a hospital bulletin.
    Six years later an ophthalmic surgeon by
    the name of Amoils improved on the device.
    Lloyd coined the term “cryoanalgesia” in 1976.
    The technique was popularized in the 1980s,
    but publications have declined since. [Cooper
    IS, Lee AS. Cryostatic congelation: a system for
    producing a limited, controlled region of cooling
    or freezing of biologic tissues.
107
Q
  1. Which of the following is (are) accurate regarding
    lesion size?
    (1) The size of a continuous radiofrequency
    lesion depends on temperature induced
    (2) The size of a continuous radiofrequency
    lesion depends on the width of the needle
    (3) A 2 mm cryoanalgesia probe forms an
    ice ball about 5.5 mm thick
    (4) A 1.4 mm cryoanalgesia probe forms an
    ice ball about 3.5 mm thick
A
  1. (E) The size of a continuous radiofrequency
    lesion depends on temperature, width of
    needle, and length of exposed (uninsulated)
    cannula. The 1.4-mm cryoanalgesia probe
    forms an ice ball about 3.5 mm thick, while the larger 2-mm probe forms and ice ball about 5.5 mm thick. Thus the ice ball is about 2.5 to 2.75 times larger than the probe for these size probes.
108
Q
  1. Which of the following is (are) components of
    a cryoanalgesia system?
    (1) Outer tube with smaller inner tube
    (2) Pressurized gas in inner tube
    (3) Fine aperture in tip of inner tube which
    allows gas to rapidly expand in tip of
    outer tube
    (4) Fine aperture in tip of outer tube which
    allows gas to escape the tube system
A
  1. (A) Acryoprobe is comprised of a tube within
    a tube. The inner tube is pressurized with a
    gas such as nitrous oxide or carbon dioxide at
    600 to 800 psi. As the gas escapes through a
    narrow aperture at the tip of the inner tube, it
    (the gas) abruptly expands in the larger outer
    tube at a lower pressure of about 10 to 15 psi.
    As the gas expands, it (the gas) cools. This is
    known as the Joule-Thompson effect. An ice
    ball then forms at the tip of the probe. The gas
    does not escape out through a fine aperture in
    the tip of the outer tube. This would allow the
    gas to enter the patient’s tissues. Instead, gas
    escapes back up the larger outer tube in a
    closed system design
109
Q
  1. Which of the following is (are) potential neuroablative
    procedure treatment options?
    (1) Radiofrequency ablation of the L2
    ramus communicans for treatment of
    L4-L5 discogenic pain
    (2) Phenol neurolysis for treatment of the
    lumbar sympathetic plexus for treatment
    of CRPS of the lower extremity
    (3) Radiofrequency ablation for treatment
    of the lumbar sympathetic plexus for
    treatment of CRPS of the lower
    extremity
    (4) Cryoablation for the treatment of pain
    owing to superior gluteal nerve
    entrapment
A
  1. (E)
  2. It has been postulated that the sinuvertebral
    nerves at each lumbar level transmit
    sensory information from the intervertebral
    discs to the paravertebral chain on each
    side. The rami communicans then communicate
    this sensory information to the dorsal
    root ganglia at L1 and L2.
  3. and 3. Both radiofrequency and phenol
    lumbar sympathetic neurolytic techniques
    have been described for the treatment of
    lower extremity CRPS.
  4. Cryoablation has been utilized for pain of
    the superior gluteal nerve. (Trescot, Pain
    Physician, 2003, v. 6, p. 345-360, Cryoanalgesia
    in interventional pain management)
110
Q
  1. Which of the following is (are) potential advantage(
    s) of pulsed radiofrequency procedure
    over continuous radiofrequency ablation?
    (1) Pulsed radiofrequency procedure is virtually
    painless as compared to continuous
    radiofrequency ablation during
    which patients often complain of pain
    (2) Overwhelming evidence of greater efficacy
    with pulsed radiofrequency procedure
    over continuous radiofrequency
    ablation
    (3) As compared to pulsed radiofrequency
    ablation, continuous radiofrequency
    ablation of lumbar medial branches carries
    a higher risk of inducing spinal
    instability secondary to multifidus
    muscle denervation
    (4) Complications caused by needle injury
    of tissues is less with pulsed radiofrequency
    procedure compared to continuous
    radiofrequency ablation
A
  1. (B)
  2. Pulsed radiofrequency procedure is virtually
    painless. Continuous radiofrequency
    ablation is painful with application.
  3. There is debate in literature as to whether
    pulsed radiofrequency procedure is as efficacious
    as radiofrequency ablation.
  4. In addition to innervating the zygapophysial
    joint, the medial branch of the dorsal ramus
    also innervates the multifidus, interspinales, and intertransversarii mediales muscles, the
    interspinous ligament, and, possibly, the ligamentum
    flavum.
  5. In both cases a cannula and radiofrequency
    probe of similar size are inserted.
111
Q
  1. Which of the following is (are) correct regarding
    impedance measurement during radiofrequency
    procedures?
    (1) While performing a radiofrequency procedure,
    the lower the impedance value
    the better the expected outcome
    (2) Impedance measurement can detect
    needle-tip entry into different mediums
    such as vascular structures or periosteum
    (3) Impedance values are neither customary
    nor necessary when using fluoroscopic
    guidance
    (4) Impedance measurement can detect
    breaks or short circuits in the electrical
    circuit
A
  1. (C)
  2. Too low an impedance may indicate the
    needle tip is in nontarget tissues such as
    vasculature, CSF, or nucleus pulposus.
  3. This statement is correct.
  4. It is traditional to use impedance information
    in assisting needle-tip placement even
    during fluoroscopically guided procedures.
  5. This statement is correct. Superior gluteal
    nerve entrapment is amenable to cryoablation.