Pain Flashcards
You are revising an intrathecal catheter in a chronic pain patient who developed myelopathy after
several years of benefit from a spinal infusion pump. You note the mass shown in the figure at the
end of the catheter tip. Which of the following factors predisposes to the formation of these
lesions?
Answers:
A. Catheter fracture
B. High drug concentration
C. Contaminated pump refills
D. Immunosuppressed status
E. Catheter allergy
High drug concentration
Discussion:
Answer, high drug concentration. This is thought to be the most important factor leading to the
development of a pump granuloma that is demonstrated in the figure. For this reason, patients are
maintained on the lowest effective dose and concentration of intrathecal medication that still
provides adequate pain relief. Pump granuloma has been reported with opiate as well as baclofen
infusions. Immunosuppression, allergy to pump system materials, catheter fracture, and drug
contamination do not tend to cause catheter tip granulomas.
References:
Hassenbusch SJ; Portenoy RK; Cousins M; Buchser E; Deer TR; Du Pen SL; Eisenach J; Follett
KA; Hildebrand KR; Krames ES; Levy RM; Palmer PP; Rathmell JP; Rauck RL; Staats PS; Stearns
L; Willis KD. Polyanalgesic Consensus Conference 2003: an update on the management of pain
by intraspinal drug delivery– report of an expert panel. J Pain Symptom Manage
2004;27(6):540-63.
Deer TR; Levy R; Prager J; Buchser E; Burton A; Caraway D; Cousins M; De Andres J; Diwan S;
Erdek M; Grigsby E; Huntoon M; Jacobs MS; Kim P; Kumar K; Leong M; Liem L; McDowell GC
2nd; Panchal S; Rauck R; Saulino M; Sitzman BT; Staats P; Stanton-Hicks M; Stearns L; Wallace
M; Willis KD; Witt W; Yaksh T; Mekhail N. Polyanalgesic Consensus Conference–2012:
recommendations to reduce morbidity and mortality in intrathecal drug delivery in the treatment of
chronic pain. Neuromodulation 2012;15(5):467-82.
A patient with V3 distribution trigeminal neuralgia undergoes a percutaneous radiofrequency
lesioning procedure. After placing the electrode at the Gasserian ganglion and performing the test
stimulation, the patient reports tingling in the V2 distribution. The surgeon wishes to reposition the
electrode to achieve V3 stimulation instead. In which of the following directions should the
electrode be moved?
Answers:
A. Inferior and anterior
B. Inferior and lateral
C. Superior and posterior
D. Superior and lateral
E. Inferior and medial
Inferior and lateral
Discussion:
Answer, inferior and lateral. The Gasserian ganglion lies along the inferomedial border of the orbit,
with V1 superomedial and V3 inferolateral in relation to the midpoint of the ganglion. The trigeminal
nerve enters Meckel’s cave and forms the trigeminal ganglion within it. The somatotopic
arrangement of the fibers of the trigeminal nerve recapitulates the postganglionic divisions of the
nerve: V1, which exits through the superior orbital fissure; V2, which exits inferiorly and more
laterally through the foramen rotundum; and V3, which exits at the lateral extent through the
foramen ovale. It is through the foramen ovale that percutaneous approaches to the Gasserian
ganglion are performed, since it is the opening in the skull base that offers the easiest access to
Meckel’s cave via the percutaneous route. This somatotopic organization is important to keep in
mind when performing such operations for trigeminal neuralgia.
References:
Tatli M, Sindou M. Anatomoradiological landmarks for
accuracy of radiofrequency thermorhizotomy in the treatment of trigeminal
neuralgia. Neurosurgery 2008;63(1 Suppl 1):ONS129-37.
Nugent GR. Technique and results of 800 percutaneous radiofrequency
thermocoagulations for trigeminal neuralgia. Appl Neurophysiol
1982;45(4-5):504-7
A 51-year-old woman with endometrial cancer has severe pain in the right leg due to local
carcinomatous invasion of the pelvic wall. The pain is not controlled with oral analgesics. Which of
the following represents the best approach for management of her pain?
Answers:
A. Dorsal rhizotomy
B. Spinal cord stimulation
C. Dorsal root entry zone lesion
D. Percutaneous C1-C2 cordotomy
E. Intrathecal opiates
Percutaneous C1-C2 cordotomy
Discussion:
Answer, percutaneous C1-C2 cordotomy. This is an excellent procedure for the treatment of
cancer pain located at or below the C5 dermatomal level for patients with limited life expectancy.
Cordotomy often produces immediate pain relief and often allows significant reduction in orally
administered opiates. An intrathecal pump could be considered, but in a patient with life
expectancy 3 months, these devices are not cost-effective. Spinal cord stimulation is not typically
used for the management of cancer pain and, in any event, would not be indicated for someone
with such a limited life expectancy. Dorsal rhizotomy for cancer pain is limited to cases in which the
tumor has not spread to a large area, such as the lower extremity. Dorsal root entry zone lesioning
is not customarily indicated for cancer pain in the lower extremity, but is most useful for unilateral
upper extremity brachial plexus avulsion pain.
References:
Viswanathan A; Bruera E. Cordotomy for treatment of cancer-related pain: patient selection and
intervention timing. Neurosurg Focus
2013;35(3):E6
Raslan AM; Cetas JS; McCartney S; Burchiel KJ. Destructive
procedures for control of cancer pain: the case for cordotomy. J Neurosurg 2011;114(1):155-70
A fifty-year old female presents with medically refractory episodes of severe, deep-seated ear and
throat pain, triggered by eating solid food. The best surgical treatment option includes
decompression or sectioning of which of the following nerves?
Answers:
A. Hypoglossal nerve
B. Inferior portion of the vagus nerve
C. Nervus intermedius
D. Glossopharyngeal nerve
E. Trigeminal nerve
Glossopharyngeal nerve
Discussion:
Answer, glossopharyngeal nerve. Glossopharyngeal neuralgia (GN) is severe, intermittent,
lancinating pain that causes sharp, stabbing pulses of pain in the back of the throat and tongue,
the tonsils, and the middle ear. GN is far less common than trigeminal neuralgia and is most often
idiopathic in nature. In some cases GN can be caused by vascular compression in the region of
the root entry zone. The posterior inferior cerebellar artery is the most commonly implicated
vessel. Tumors of the region of the jugular foramen may also cause secondary GN. Division of the
glossopharyngeal nerve and the upper 1/3 of the vagus nerve is a highly effective treatment for
glossopharyngeal neuralgia. Post-operative testing may reveal diminished sensation over the
pharynx, reduction of the gag reflex on the affected side, and absence of taste on the posterior
third of the tongue, however there is rarely any significant long-lasting clinical effect on swallowing.
Alternatively, patients with glossopharyngeal neuralgia may be treated with microvascular
decompression if is obvious evidence of vascular compression. Gamma kniferadio surgery has
been reported to be an effective treatment for GN as well. Caudalis DREZ might be considered as
a last resort in persons who remain with intractable pain following other treatments.
References:
Patel A, Kassam A, Horowitz M, Chang YF. Microvascular
decompression in the management of glossopharyngeal neuralgia: analysis of 217
cases. Neurosurgery 2002;50(4):705-10.
Kondo A. Follow-up results of using microvascular
decompression for treatment of glossopharyngeal neuralgia. J Neurosurg 1998;
88:221-225.
Rozen TD. Trigeminal neuralgia and glossopharyngeal
neuralgia. Neurol Clin 2004;22(1):185-206.
A 79-year-old woman with a history of multiple strokes and cardiac arrhythmia requiring
anticoagulation, presents with medically-refractory V1 trigeminal neuralgia. What is the most
appropriate treatment option for this patient?
Answers:
A. Supraorbital alcohol injection
B. Microvascular decompression
C. Percutaneous radiofrequency rhizotomy
D. Stereotactic radiosurgery
E. Supraorbital neurectomy
Stereotactic radiosurgery
Discussion:
Answer, stereotactic radiosurgery. This represents the most effective option with the least side
effects in this patient. Elderly patients may be candidates for microvascular decompression in
select cases, but the risk of complications goes up in the setting of multiple medical comorbidities,
as in this case. Although the percutaneous lesioning procedures can be effective for elderly
patients who desire a less invasive approach than open surgery, they can result in corneal
denervation and ulceration following the treatment of V1 distribution pain. Peripheral nerve ablative
procedures are not normally considered for the definitive treatment of trigeminal neuralgia, as the
resultant denervation may precipitate anesthesia dolorosa.
References:
Maesawa S, Salame C, Flickinger JC, et al. Clinical outcomes
after stereotactic radiosurgery for idiopathic trigeminal neuralgia. J
Neurosurg 2001;94:14-20
Brisman R. Gamma knife radiosurgery for primary management
for trigeminal neuralgia. J Neurosurg 2000;93:159-161
Bhatti MT; Patel R. Neuro-ophthalmic considerations in
trigeminal neuralgia and its surgical treatment. Curr Opin Ophthalmol 2005;16(6):334-40
In the diagram, which number corresponds to the target of a cordotomy procedure?
Answers:
A. 3
B. 2
C. 1
D. 5
E. 4
4
Discussion:
Answer, 4. Cordotomy consists of surgical interruption of the anterolateral spinothalamic tract (4).
Knowledge of spinal cord tract organization is paramount for the safe performance of ablative
procedures for pain, such as cordotomy. It can be performed either percutaneously at C1, or by an
open procedure in the thoracic spinal cord. Care must be taken during this procedure to stay
ventral to the dentate ligament, which separates the dorsally located corticospinal tract (3) from the
spinothalamic tract. The dorsal root entry zone (2) is the target for DREZ lesioning procedures,
and the midline pain pathway (1) is the target for the midline myelotomy for visceral pain. The
ventral white decussation (5) contains fibers from both spinothalamic tracts and is the target for
commissural myelotomies.
References:
Raslan AM, Cetas JS, McCartney S, et al. Destructive procedures for control of cancer pain: the
case for cordotomy. J Neurosurg. 2011;114(1):155-70.
Kanpolat Y, Ugur HC, Ayten M, et al. Computed tomography-guided percutaneous cordotomy for
intractable pain in malignancy. Neurosurgery. 2009;64(3 Suppl):ons187-93
A 45-year-old woman is referred with complaints of debilitating paroxysmal, lancinating pain
involving the base of the tongue and tonsillar region on the left side. The pain can be relieved by
topical application of cocaine to the tonsillar pillar. Her neurological examination and imaging of the
skull base are normal. What is the most likely diagnosis?
Answers:
A. Meningioma in the CPA angle
B. Eagle syndrome
C. Glossopharyngeal neuralgia
D. Geniculate neuralgia
E. Trigeminal neuralgia
Glossopharyngeal neuralgia
Discussion:
Answer, glossopharyngeal neuralgia. The character of the pain associated with glossopharyngeal
neuralgia (GN) is similar to that of trigeminal neuralgia in that the typical pain is severe,
intermittent, and lancinating. In some patients the pain may radiate to the ear and be confused with
geniculate neuralgia. GN is far less common than trigeminal neuralgia and is most often idiopathic
in nature. Similar to trigeminal neuralgia, it has been suggested that the primary cause of GN is
vascular compression in the region of the root entry zone. The posterior inferior cerebellar artery is
the most commonly implicated vessel. Pain relief with application of cocaine is a classic diagnostic
maneuver. Glossopharyngeal neuralgia is less commonly related to secondary causes. Eagle
syndrome is a condition where an elongated styoid process produces extracranial compression of
the 9th nerve. Tumors may also cause secondary GN. The normal imaging in this patient makes
this possibility much less likely in this case. When trigeminal neuralgia is related to tumor in the CP
angle, it is most likely a benign lesion such as a meningioma or schwannoma. However, when GN
is related to a tumor in the region of the jugular foramen, the lesion is more likely to be malignant.
Division of the glossopharyngeal nerve and the upper 1/3 of the vagus nerve is a highly effective
treatment for glossopharyngeal neuralgia. Careful testing may reveal diminished sensation over
the pharynx, reduction of the gag reflex on the affected side, and absence of taste on the posterior
third of the tongue; there is rarely any significant long-lasting clinical effect on swallow.
Alternatively, patients with glossopharyngeal neuralgia may be treated with microvascular
decompression in the event there is obvious evidence of vascular compression. Percutaneous RF
lesioning of the nerve in the jugular foramen has been described but is associated with a high risk
of injury to the vagus nerve. Similar problems are associated with extracranial sectioning of the
nerve due to the proximity of the tenth nerve and the jugular bulb.
References:
Patel A, Kassam A, Horowitz M, Chang YF. Microvascular
decompression in the management of glossopharyngeal neuralgia: analysis of 217
cases. Neurosurgery 2002;50(4):705-10.
Kondo A. Follow-up results of using microvascular
decompression for treatment of glossopharyngeal neuralgia. J Neurosurg 1998;
88:221-225.
Rozen TD. Trigeminal neuralgia and glossopharyngeal
neuralgia. Neurol Clin 2004;22(1):185-206.
What is the BEST pain procedure for treating pelvic and/or rectal pain due to ovarian carcinoma?
Answers:
A. Spinal cord stimulation
B. Dorsal root entry zone procedure
C. Punctate midline myelotomy
D. Sacral rhizotomy
E. Sacral root stimulation
Punctate midline myelotomy
Discussion:
Answer, punctate midline myelotomy. This is an ablative procedure that holds great promise in
relief of pelvic and visceral pain due its ability to disrupt the midline visceral pathway. Similar to
cordotomy, the goal of this procedure is to interrupt the afferent visceral pain fibers of the midline
dorsal column, which are thought to carry more nociceptive visceral information than the
spinothalamic pathways. Typically, a 5mm deep and 1mm wide midline posterior punctate lesion is
made with a needle or microdissector in the upper third of the thoracic spine. Spinal cord
stimulation has no significant role in treatment of midline visceral pain of this nature. Similarly,
sacral root stimulation or destruction are unlikely to be helpful, due to the diffuse, nociceptive
nature of the pain. The dorsal root entry zone procedure is best suited for root avulsion pain
syndromes, and is unlikely to have a beneficial effect in this patient.
References:
Nauta HJ, Soukup VM, Fabian RH, et al. Punctate midline
myelotomy for the relief of visceral cancer pain. J Neurosurg 2000;92:125-130.
Nauta HJ, Hewitt E, Westlund KN, Willis WD. Surgical
interruption of a midline dorsal column visceral pain pathway. Case report and
review of the literature. J Neurosurg 1997;86:538-542.
Hong D1, Andrén-Sandberg A. Punctate midline myelotomy: a
minimally invasive procedure for the treatment of pain in inextirpable
abdominal and pelvic cancer. J Pain Symptom Manage 2007;33(1):99-109.
A 45-year-old woman with colon cancer presents with severe bilateral pain in her abdomen and
pelvis due to multiple metastases. Although her pain has been responsive to oral narcotics,
escalating doses have given her unacceptable sedating side effects. Which of the following
interventions would be MOST appropriate in this setting?
Answers:
A. Oral buprenorphine trial
B. Percutaneous cordotomy
C. Intrathecal morphine trial
D. Dorsal root entry zone procedure
E. Spinal cord stimulation trial
Intrathecal morphine trial
Discussion:
Answer, intrathecal morphine trial. Increasing sedation in the face of otherwise opiate-responsive
pain is the primary indication for considering intrathecal analgesia. In this setting, the patient has
pain that is responsive to morphine; however, her medical regimen is complicated by sedation.
Prior to placement of a morphine pump, a trial dose of morphine is essential in order to assess
efficacy and possible side effects. Buprenorphine is a synthetic opiate agonist-antagonist used to
treat narcotic abuse. It can also be used to treat moderate pain in non-opiate tolerant patients, but
would not be appropriate in a patient with severe, medically-refractory pain. Spinal cord stimulation
would not likely be effective for acute, bilateral abdominal and pelvic pain. In some cases of
chronic, benign neuropathic abdominal and pelvic pain, spinal cord stimulation could be an option,
but it is not generally considered for cancer pain. The dorsal root entry zone (DREZ) procedure is
used to treat upper extremity pain that results from nerve root avulsion injury, and would not be
useful here. Percutaneous cordotomy is typically used to treat unilateral cancer pain.
References:
Hassenbusch SJ. Surgical management of cancer pain.
Neurosurg Clin N Am 1995;6:127-134
Burton AW, Rajagopal A, Shah HN, Mendoza T, Cleeland C,
Hassenbusch SJ 3rd, Arens JF. Epidural and intrathecal analgesia is effective
in treating refractory cancer pain. Pain Med 2004;5(3):239-47
A 37-year-old is experiencing severe pain in his left arm following a motorcycle accident in which
he suffered a traumatic brachial plexus avulsion. Two years later, the patient continues to have a
flail arm with no evidence of return of function. Medical therapy has failed to relieve his symptoms.
Which of the following is the BEST treatment for this patient’s pain?
Answers:
A. Neurotization of denervated segments
B. Lesion of the dorsal root entry zone
C. Limb amputation
D. Peripheral nerve stimulator implantation
E. Peripheral neurectomy at denervated segments
Lesion of the dorsal root entry zone
Discussion:
Answer, lesion of the dorsal root entry zone. This procedure successfully treats brachial plexus
avulsion pain in 50-70% of cases in the long term. It is one of the few ablative procedures with
long-term benefit in nonmalignant pain. It should be reserved for patients who do not have any
evidence of recovery of function over the long term. Interestingly, neurotization surgery, when used
as a treatment for weakness, does seem to help with avulsion pain as the patients experience
motor recovery. Unfortunately, neurotization procedures are unlikely to add any benefit at this late
stage. Peripheral neurectomy and limb amputation would not offer any benefit, since avulsion pain
is a central, deafferentation pain, not peripherally-generated. Although peripheral nerve stimulation
may be useful for central as well as peripheral neuropathic pain syndromes, this therapy requires
at least a partially intact sensory pathway to act as a substrate. Thus, it would be of no use on
nerves that are physically disconnected from the central nervous system, as in root avulsion.
References:
Wellos JC et al: “Stump and Phantom Limb, and Avulsion Pain,” in Burchiel KJ (Ed), Surgical
Management of Pain. New York: Thieme; 2002: 433.
Friedman AH, Nashold BS, Jr., Bronec PR. Dorsal root entry
zone lesions for the treatment of brachial plexus avulsion injuries: a
follow-up study. Neurosurgery 1988;22:369-373
Sindou MP, Blondet E, Emery E, Mertens P. Microsurgical
lesioning in the dorsal root entry zone for pain due to brachial plexus
avulsion: a prospective series of 55 patients. J Neurosurg 2005;102(6):1018-28.
A patient with an L5 radiculopathy and chronic low back pain with an intrathecal morphine pump
presents with increasing pain despite very high doses of intrathecal morphine. In addition, the
patient has begun to complain of a weak left foot. Upon examination, the patient has slight
dorsiflexor weakness in the left foot and hyperreflexia in the lower extremities. What is the most
likely explanation for this presentation?
Answers:
A. Catheter-tip granuloma
B. Hardware infection
C. Morphine neurotoxicity
D. Exacerbation of L5 radiculopathy
E. Catheter fracture
Catheter-tip granuloma
Discussion:
Answer, catheter-tip granuloma. Prolonged intrathecal therapy using high doses of morphine may
be complicated by the development of catheter tip sterile granulomas. This uncommon
complication of therapy typically is associated with increased pain, progressive neurologic deficit,
and upper motor neuron signs (caused by compression of the spinal cord at the region of the
catheter tip). Treatment for catheter tip granulomas ranges from cessation of therapy for mild
symptoms to emergent decompression with removal of granuloma for more severe myelopathic
symptoms. A fracture of the intrathecal catheter does result in increased pain, but it is not typically
associated with neurological findings. Similarly, exacerbation of chronic radiculopathy may result in
increased pain as well as exacerbation of previously demonstrated deficit. However, upper motor
neuron signs such as hyperreflexia are absent. Catheter system infections are also uncommon.
They typically present with wound complications and/or fevers.
References:
Coffey RJ, Burchiel KJ. Inflammatory mass lesions associated with intrathecal drug infusion
catheters: report and observations on 41 patients. Neurosurgery 50:78-86, 2002.
Blount JP, Remley KB, Yue SK, et al. Intrathecal granuloma
complicating chronic spinal infusion of morphine. Report of three cases. J
Neurosurg 1996;84:272-6.
Cabbell KL, Taren JA, Sagher O. Spinal cord compression by
catheter granulomas in high-dose intrathecal morphine therapy: case report.
Neurosurgery 1998;42:1176-80
Langsam A. Spinal cord compression by catheter granulomas in
high-dose intrathecal morphine therapy: case report. Neurosurgery 1999;44:689-91.
A 76-year-old female has a history of lancinating pain just below her right eye. You performed
stereotactic radiosurgery on her 1 year ago, giving her excellent pain relief for 9 months. She now
returns to you complaining of constant burning pain and diminished sensation where her
lancinating pain used to be. What is this patient’s most likely diagnosis at follow-up?
Answers:
A. Trigeminal deafferentation pain
B. Trigeminal neuropathic pain
C. Anesthesia dolorosa
D. Symptomatic trigeminal neuralgia
E. Type 1 trigeminal neuralgia
Trigeminal deafferentation pain
Discussion:
Answer, trigeminal deafferentation pain. It is a type of deafferentation pain that develops following
ablative treatment for trigeminal neuralgia. This pain is usually distinctly different than the patient’s
original trigeminal neuralgia pain. It is usually constant and burning, and occurs in the territory of
reduced, but not anesthetic, sensation. Pain that occurs in an anesthetic trigeminal territory is
called anesthesia dolorosa. Trigeminal neuropathic pain is a similar form of deafferentation pain to
trigeminal deafferentation pain, except that it occurs in patients who do not have a history of
trigeminal neuralgia. It, too, occurs in a trigeminal distribution following nerve damage, often with
perceptibly reduced sensation. Type 1 trigeminal neuralgia consists of intermittent, often
lancinating pain, and is likely what this patient had prior to her radiosurgery treatment.
Symptomatic trigeminal neuralgia is multiple sclerosis-associated trigeminal neuralgia.
References:
Burchiel KJ. A new classification for facial pain.
Neurosurgery 2003;53(5):1164-6.
Pollock BE, Phuong LK, Foote RL, et al: High-dose trigeminal
neuralgia radiosurgery associated with increased risk of trigeminal
dysfunction. Neurosurgery 2001;49:58-64
Midline myelotomy is an ablative pain procedure most often used for the treatment of pain in which
of the following parts of the body?
Answers:
A. Arm
B. Face
C. Leg
D. Pelvis
E. Trunk
Pelvis
Discussion:
Punctate midline myelotomy is an ablative procedure that holds great promise in relief of pelvic
and visceral pain due its ability to disrupt the midline visceral pathway. Similar to cordotomy, the
goal of this procedure is to interrupt the afferent visceral pain fibers of the midline dorsal column,
which are thought to carry more nociceptive visceral information than the spinothalamic pathways.
Typically, a 5mm deep and 1mm wide midline posterior punctate lesion is made with a needle or
microdissector in the upper third of the thoracic spine. Myelotomy has no significant role in the
treatment of pain in the face, arm, leg, or trunk.
References:
Nauta HJ, Soukup VM, Fabian RH, et al. Punctate midline
myelotomy for the relief of visceral cancer pain. J Neurosurg 2000;92:125-130.
Nauta HJ, Hewitt E, Westlund KN, Willis WD. Surgical
interruption of a midline dorsal column visceral pain pathway. Case report and
review of the literature. J Neurosurg 1997;86:538-542.
Hong D1, Andrén-Sandberg A. Punctate midline myelotomy: a
minimally invasive procedure for the treatment of pain in inextirpable
abdominal and pelvic cancer. J Pain Symptom Manage 2007;33(1):99-109.
The anterior cingulate cortex (ACC) is most notably involved in which aspect of pain?
Answers:
A. Distinguishing neuropathic and nociceptive
B. Modulating the affective components
C. Determining the spatial components
D. Moderating pain severity
E. Discriminating sharp and dull
Modulating the affective components
Discussion:
The anterior cingulate cortex is thought to play an important role within the medial pain pathway,
which is, in part, responsible for processing the affective component of pain. The affective
component includes the emotional reaction to pain and to what degree the person is bothered by
the pain. In contrast, the lateral pathway, which includes connections to the primary
somatosensory cortex, mediates the actual physical sensation of pain. It is also important for
distinguishing other pain characteristics, such as location, quality, and severity of the pain.
An understanding of the medial and lateral pathways is important, as some pain therapies target a
specific pathway. For example, cingulotomy, BURST spinal cord stimulation, and
tetrahydrocannabinol (THC), an important component in medical cannabis, all are thought to
selectively influence the activity of the medial pain pathway, and thus influence pain responses by
targeting the affective content of the pain.
References:
Sharim J, Pouratian N. Anterior cingulotomy for the treatment of chronic intractable pain: a
systematic review. Pain Physician 2016;19:537-50.
Vogt BA, Sikes RW. The medial pain system, cingulate cortex, and parallel processing of
nociceptive information. Prog Brain Res 2000;122:223-35.
Dorsal root entry zone (DREZ) lesions are most likely to be effective in relieving which of the
following types of pain?
Answers:
A. Postherpetic neuralgia in the groin
B. Pelvic pain from metastatic cancer
C. Peripheral neuropathy pain in the feet
D. Root avulsion pain in the arm
E. Intercostal neuralgia in the trunk
Root avulsion pain in the arm
Discussion:
DREZ lesions are most effective for unilateral upper extremity pain secondary to brachial plexus
avulsion injury and Pancoast tumor. The procedure interrupts the inbound afferent pain pathways
as they enter the spinal cord at the level of the dorsal horn. Unilateral arm pain secondary to spinal
cord injury may also respond well to the DREZ procedure. This procedure is generally not a good
treatment option for pain in the trunk, groin, bilateral lower extremities, or pelvis.
References:
Friedman AH, Nashold BS, Jr., Bronec PR. Dorsal root entry
zone lesions for the treatment of brachial plexus avulsion injuries: a
follow-up study. Neurosurgery 1988;22:369-373.
Sindou MP, Blondet E, Emery E, Mertens P. Microsurgical
lesioning in the dorsal root entry zone for pain due to brachial plexus
avulsion: a prospective series of 55 patients. J Neurosurg 2005;102(6):1018-28.
Konrad P. Dorsal root entry zone lesion, midline myelotomy and anterolateral cordotomy.
Neurosurg Clin N Am 2014;25:699–722
