Adult Neurosurgery Flashcards
Which tumor is associated with hydrocephalus
and sudden death?
A. Colloid cyst
B. Glioblastoma multiforme
C. Lymphoma
D. Pilocytic astrocytoma
A. Colloid cyst
Colloid cysts represent 0.5 to 2% of all brain tumors and occur in the anterior part of the third ventricle near the foramen of Monro. These lesions can be associated with the development of hydro- cephalus and rapid clinical deterioration. Sudden death has been reported but is rare, and likely involves the colloid cyst acting as a ball valve and suddenly shifting and occluding cerebrospinal fluid outflow.
Complex regional pain syndrome type 2 (formerly known as causalgia) is defined by what symptoms?
A. Burning pain, autonomic dysfunction, and tro-phic changes following obvious nerve damage
B. Increased perspiration in excess of what is re-
quired for regulation of body temperature
C. Burning pain, autonomic dysfunction, and tro-
phic changes without obvious nerve damage
D. An initial lack of sensation and tingling on one
side of the body followed later by severe,
chronic dysesthesias or allodynia
E. Recurrent hospitalizations with dramatic, un-
true, and extremely improbable tales of past
experiences
A. Burning pain, autonomic dysfunction, and tro-phic changes following obvious nerve damage
Complex regional pain syndrome (CRPS) type 2 follows nerve injury and originally was described following high-velocity missile injuries. CRPS type 1 (also known as reflex sympathetic dystrophy) is similar to CRPS type 2 in symptoms but does not demonstrate obvious nerve damage. (B) Increased perspiration in excess of what is required for regu- lation of body temperature suggests hyperhidro- sis. (C) CRPS type 2 requires nerve damage for the diagnosis. (D) Dejerine-Roussy syndrome follows a thalamic stroke and is characterized by an initial lack of sensation and tingling on one side of the body followed later by severe, chronic dysesthesias or allodynia. (E) Munchausen syndrome is charac- terized by recurrent hospitalizations with dramatic, untrue, and extremely improbable tales of past experiences.
What factors contribute to the intracranial hemor-
rhage (ICH) score for a patient with a hemorrhagic
stroke?
A. Patient age, Glasgow Coma Scale (GCS) score,
acuity of ICH
B. ICH volume, GCS score, acuity of ICH
C. Intraventricular hemorrhage (IVH), position of ICH, patient age
D. Position of ICH, patient age, baseline Karnofsky
Scale score
E. Patient age, IVH, hemiplegia
C. Intraventricular hemorrhage (IVH), position of ICH, patient age
The intracranial hemorrhage (ICH) score is cal- culated from four factors: Glasgow Coma Scale (GCS) score, ICH volume, whether or not the ICH is infratentorial, and patient age. A GCS score of 3–4 yields two points, 5–12 yields one point, and 13–15 yields no points. One point is given to an ICH at least 30 cm3 in size, and an additional point is given to an ICH with an infratentorial origin. Finally, one point is given if the patient is at least 80 years old. The ICH score thus ranges from 0 to 6.
A patient with a history of intravenous drug use is
seen in clinic with new-onset severe back pain. An
MRI is obtained that demonstrates bony erosion
and collapse of the L2/L3 disk. What is the next
step in the management of this patient?
A. Perform a lumbar puncture, and send spinal
fluid cultures.
B. Obtain a CT scan of the spine.
C. Obtain blood cultures.
D. Obtain a bone scan.
E. Schedule follow-up with a repeat MRI in 4 to 6
weeks.
C. Obtain blood cultures.
The likely diagnosis is diskitis, and the next step is to obtain blood cultures to confirm the hematogenous source and obtain an organism to treat. If blood cultures are negative, guided needle biopsy of the disk space should be done. Obtaining a serum erythrocyte sedimentation rate and C-reactive protein concentration also can be helpful. (A) A lumbar puncture is contraindicated due to the possibility of seeding the intrathecal space with an infectious agent.
How is mechanical back pain associated with
activity?
A. Improves with activity
B. Worsens with activity
C. Relieved by standing
D. Worsens with axial unloading
A. Improves with activity
Although some patients with severe back pain and muscle spasms may improve with no more than 48 hours of bed rest, patients with mild to moderate back pain should return to near-normal work schedules and have improvement in back pain with activity, as this increases flexibility.
Where should the dissection take place during a
transpsoas approach to the lumbar spine in order
to minimize the risk of nerve injury?
A. Anterior to the psoas major
B. Posterior to the psoas major
C. Through the bulk of the psoas major
D. Along the medial aspect of the psoas major
E. Along the lateral aspect of the psoas major
C. Through the bulk of the psoas major
The transpsoas approach to the lumbar spine places the entire lumbosacral plexus at risk for injury. The risk can be minimized by staying in the bulk of the psoas major muscle and with close neuromonitoring.
A 17-year-old girl presents to the neuro-ophthal-
mology clinic with complaints of episodic diplopia
that has been present for the past week. The epi-
sodes occur about every hour and last around 1
minute each time. The patient has a history of a
transsphenoidal resection of a craniopharyngioma
3 years ago followed by radiation. Postoperative
ophthalmologic exams including visual fields have
been unremarkable. An MRI from 1 month ago
demonstrated no evidence of recurrent disease.
The patient is examined during one of these epi-
sodes and is found to have an exotropia of her right
eye that resolves spontaneously. She is prescribed
carbamazepine, and her symptoms improve. What
is her most likely diagnosis?
A. Craniopharyngioma recurrence
B. Myasthenia gravis
C. Ocular neuromyotonia
D. Seizures
C. Ocular neuromyotonia
Although rare, ocular neuromyotonia can occur after skull base radiation, with a reported mean time of 3.5 years following radiation. It is char- acterized by episodic, tonic contractions of one or more extraocular muscles, resulting in episodic diplopia. Varying success has been reported with membrane stabilizing agents (antiepileptics) or strabismus surgery.
A man presents to clinic with results from an elec-
tromyographic (EMG) study showing fibrillations
and reduced motor unit potentials in his gluteus
medius and extensor digitorum longus. He has no
abnormal EMG findings in his biceps femoris (short
head). Weakness of foot eversion and numbness
on the dorsum of the foot are noted on his exam.
What nerve(s) is/are being affected?
A. L4 nerve root only
B. L5 nerve root only
C. S1 nerve root only
D. Common peroneal nerve proximal to the fibu-
lar head only
E. L5 nerve root and common peroneal nerve at
the fibular head
E. L5 nerve root and common peroneal nerve at
the fibular head
This patient has an injury to the L5 nerve root and the common peroneal nerve as explained. The peroneal nerve must be affected after it has given off its motor innervation to the short head of the biceps femoris, as this muscle is unaffected. The common peroneal nerve is most commonly injured as it crosses the fibular head, resulting in the symp- toms seen in this clinical scenario. The fibrilla- tions present on electromyography can indicate an axonal injury and uncontrolled and spontaneous firing of muscle cells. Present but reduced motor unit potentials indicate reduced motor unit recruit- ment and can indicate impeded nerve conduction. (A) With an L4 nerve root abnormality, abnormal- ities of the tibialis anterior would be expected. (B) An L5 nerve root abnormality explains the abnormalities in the extensor digitorum longus and gluteus medius but fails to address the abnormalities seen in the common peroneal nerve. Abnormalities in the gluteus minimus also would be seen with an L5 nerve root abnormality. (C) The S1 nerve root innervates the peroneus longus and brevis. (D) The common peroneal nerve supplies the short head of the biceps femoris before pass- ing around the fibular head and branching into a superficial and deep branch. The superficial branch supplies motor innervations to the muscles of the lateral compartment of the leg (the peroneus lon- gus and brevis, which evert the foot) along with sensory innervation to the lateral leg. The deep branch supplies motor innervation to the muscles of the anterior compartment of the leg (the tibialis anterior, extensor hallucis longus, extensor digi- torum longus, and peroneus tertius) along with muscles in the foot. It supplies sensory innervation to the dorsum of the foot in the first web space.
A malignant peripheral nerve sheath tumor is dis-
covered in a patient’s left upper extremity. Where
should screening first be focused to detect distant
metastases?
A. Brain
B. Other extremities
C. Axial skeleton
D. Lungs
E. Lymph nodes
D. Lungs
When malignant peripheral nerve sheath tumors (MPNSTs) are discovered, a chest CT (fine cut) should be ordered to look for metastatic disease, as this is the most common location of metastatic spread. (E) Metastases of MPNSTs rarely occur in locations like the lymph nodes or the heart.
What type of spinal arteriovenous malformation
typically is associated with low blood flow?
A. Dural
B. Juvenile
C. Extramedullary/intradural
D. Glomus
A. Dural
The American/English/French arteriovenous mal- formation (AVM) classification divides spinal vas- cular malformations into four types. Type 1 (dural AVM) is the most common; a radicular artery feeds into an engorged spinal vein along the posterior cord. This type is low flow. Type 2 (spinal glomus AVM) is a true AVM of the spinal cord. Type 3 (juvenile spinal AVM) is an enlarged glomus AVM that occupies the entire cross section of the cord and invades the vertebral body. This type may cause scoliosis. Type 4 (perimedullary AVM) forms a direct fistula between arteries supplying the spinal cord and draining veins. (C) Extramedullary/ intradural is not an AVM type and instead refers to an anatomic location typically used when describ- ing spinal neoplasms.
Multiple sclerosis is a contraindication to what
procedural treatment for trigeminal neuralgia?
A. Microvascular decompression
B. Percutaneous radiofrequency rhizotomy
C. Percutaneous glycerol injection into the Meckel
cave
D. Percutaneous balloon microcompression
E. Stereotactic radiosurgery
A. Microvascular decompression
Although multiple sclerosis patients have a poorer response than patients without the disease to any treatment for trigeminal neuralgia, patients with multiple sclerosis respond very poorly to micro- vascular decompression.
What is the major complication of a stereotactic
mesencephalotomy for medically intractable right
upper extremity pain?
A. Ipsilateral weakness
B. Anesthesia dolorosa
C. Memory deficits
D. Diplopia
E. Hypothalamic dysfunction
D. Diplopia
Diplopia can occur following a stereotactic mes- encephalotomy secondary to lesioning near the inferior colliculus. The diplopia is due to a defect in vertical eye movements and often resolves. (A) No motor tracts are encountered during a stereotactic mesencephalotomy. Weakness in the extremities is more likely to occur during a cordotomy.
A patient undergoing a craniotomy for resection of
a vestibular schwannoma has a reasonable chance
of losing serviceable hearing following surgery if
the preoperative speech discrimination is below
what percentage?
A. 50%
B. 65%
C. 75%
D. 85%
E. 95%
C. 75%
Although the definition of serviceable hearing varies, most sources require a speech discrimina- tion score of at least 50 to 70%. For preoperative counseling, a speech discrimination score under 75% significantly raises the risk of not having ser- viceable hearing following a vestibular schwan- noma resection.
A woman with a known pituitary macroadenoma
presents to the emergency room with a sudden,
intense headache and a new-onset ophthalmo-
plegia with her chronic visual field cuts. She en-
dorses photophobia. After imaging confirms the
most likely diagnosis, what is the next step in her
management?
A. Sumatriptan administration
B. Follow-up with repeat imaging in 6 weeks
C. Repeat pituitary lab work as an outpatient
D. Observation
E. Preparation for transsphenoidal decompres-
sion immediately
E. Preparation for transsphenoidal decompres-
sion immediately
The patient displays symptoms of pituitary apoplexy caused by a rapid expansion of her known pituitary adenoma secondary to necrosis or hemorrhage. This can lead to headache, nausea, somnolence, and other neurologic changes due to elevations in intracranial pressure along with exacerbated visual field cuts and ophthalmoplegia due to local mass effect. Treatment is emergent decompression of the sella turcica and pituitary lesion. Immediate administration of a stress dose of steroids also is important. Subarachnoid hemor- rhage can be seen with pituitary apoplexy, and an angiogram can be useful to rule out an aneurysm as a cause. (A) The patient likely is not having a migraine due to the new ophthalmoplegia with a known pituitary tumor. (B, D) This patient needs treatment soon to avoid permanent ophthalmic injury and neurologic damage associated with ele- vated intracranial pressures. (C) Lab work is unlikely to aid in the treatment of this patient as the pitu- itary lesion is unlikely to have grown suddenly. Outpatient lab work and waiting for inpatient labs to return will not affect the need for definitive treatment.
A woman is referred to you for treatment of a cere-
bellopontine angle tumor. She has obvious weak-
ness of the right side of her face. She does have
some motion but has no motor contraction over
her forehead, she cannot close her eye completely,
and she has noticeable asymmetry of her mouth
when attempting to smile. What is her House-
Brackmann classification grade?
A. 2
B. 3
C. 4
D. 5
E. 6
C. 4
House-Brackmann facial nerve function classifi- cation grading ranges from 1 (normal) to 6 (total paralysis). Grade 2 is mild dysfunction. Grade 3 is obvious but not disfiguring facial asymmetry. Grade 4 dysfunction entails the inability to close the eye. Grade 5 is barely perceptible motion.
What form of nicotine potentially will not decrease
spinal fusion rates?
A. Cigarette smoking
B. Chewing tobacco
C. Nicotine gum
D. Nicotine patches
E. No form of nicotine avoids the risk of de-creased spinal fusion rates
E. No form of nicotine avoids the risk of de-creased spinal fusion rates
Nicotine in all its forms has been shown to affect adversely spinal fusion rates
What is the recommended torque used on a halo
pin on an adult skull?
A. 4 in-lbs
B. 8 in-lbs
C. 12 in-lbs
D. 20 in-lbs
E. 30 in-lbs
B. 8 in-lbs
(E) The recommended torque for the screws on many halo vests is 30 in-lbs.
Injury to the subthalamic nucleus during a func-
tional lesioning procedure classically produces
what type of movement disorder?
A. Myoclonus
B. Hemiballism
C. Pill-rolling tremor
D. Fixed posture of limbs
E. Chorea
B. Hemiballism
Hemiballism is a unilateral, involuntary jerking of the proximal limb due to a lesion of the suthalamic nucleus. (A) Myoclonus describes shock-like con- tractions that are irregular and asymmetric and can have numerous etiologies. (C) A pill-rolling tremor is characteristic of parkinsonism and pathology involving the substantia nigra pars compacta. (D) Dystonias leading to fixed limb postures may be due to putaminal destruction. (E) Chorea is seen in Huntington disease and is a result of striatum atrophy.
Deep brain stimulation in the setting of Parkinson
disease is expected to result in brief minimal im-
provement to what characteristic of the disease?
A. Dyskinesia
B. Balance
C. Tremors
D. Rigidity
E. Cognitive impairment
B. Balance
Patients with Parkinson disease who have under- gone deep brain stimulation surgery experience a brief period of improvement in balance followed by a return of balance difficulties. The procedure is more effective at reliving symptoms of dyskinesia, tremors, and rigidity.
What electromyography/nerve conduction study
finding supports a diagnosis of lumbar radiculo-
pathy from a herniated disk?
A. Paraspinal muscle fibrillations
B. Abnormal sensory nerve action potentials
(SNAPs)
C. Increased motor fiber recruitment with voli-
tional activity
D. Absence of spontaneous sensory nerve activity
A. Paraspinal muscle fibrillations
Electromyography is not sensitive for radiculop- athy; however, when it is abnormal, it is very spe- cific. Paraspinal muscles are innervated by dorsal rami, which exit proximally to the dorsal root gan- glion. Paraspinal muscle fibrillations can indicate irritation of these dorsal rami. (B) Sensory nerve action potentials (SNAPs) are normal in lesions proximal to the dorsal root ganglia; therefore, most disk herniations do not affect SNAPs. (C) Increased motor fiber recruitment indicates a myopathic pro- cess. (D) Spontaneous nerve activity (including positive sharp waves and fibrillation potentials) can be seen after denervation.
A patient presents with a blunt cerebrovascular
injury after a motor vehicle collision. The patient
has no intracranial hemorrhage. CT angiogram
reveals an internal carotid artery luminal irregu-
larity with < 25% stenosis. What is the next step in
the management of this patient?
A. No acute intervention; repeat imaging in 4 to
6 weeks.
B. Initiate a heparin drip if there are no contraindications.
C. Perform endovascular stenting.
D. Perform a ligation/occlusion of carotid artery.
E. Initiate antiplatelet therapy if there are no
contraindications.
B. Initiate a heparin drip if there are no contraindications.
Blunt cerebrovascular injuries of the internal carotid artery are common following motor vehi- cle collisions and are thought to be related to neck hyperextension with lateral rotation. The injuries most often occur 2 cm from the origin of the inter- nal carotid artery. The blunt cerebrovascular injury (BCVI) classification is as follows: grade 1, luminal irregularity with ≤ 25% stenosis; grade 2, luminal irregularity with > 25% stenosis or an intralumi- nal thrombus/raised intimal flap; grade 3, pseudo- aneurysm; grade 4, complete occlusion; grade 5, transection with extravasation. The incidence of stroke increases with the grade. Although outcomes are not entirely known, the data suggest that anti- coagulation may reduce the risk of injury progres- sion with grade 1 injuries.
Halo bracing is least effective for what type of cer-
vical fractures?
A. Odontoid fractures
B. Levine type 2 pars fractures
C. Midcervical spine fractures
D. C1 fractures with a type 3 odontoid fracture
E. Teardrop fractures
C. Midcervical spine fractures
Because of “snaking,” which may occur between the halo fixation points and the vest, a halo brace is best suited for upper and lower cervical spinal fractures but is poor at maintaining distraction.
For nonemergent neurosurgical procedures, it is
recommended that a patient’s INR be less than or
equal to what value?
A. Posterior inferior cerebellar artery
B. Anterior inferior cerebellar artery
C. Superior cerebellar artery
D. Posterior cerebellar artery
E. Vertebral artery
B. Anterior inferior cerebellar artery
The anterior inferior cerebellar artery can com- press cranial nerve VII to produce hemifacial spasm. (A) The posterior inferior cerebellar artery is asso- ciated with glossopharyngeal neuralgia. (C) The superior cerebellar artery is associated with tri- geminal neuralgia.
For nonemergent neurosurgical procedures, it is recommended that a patient’s INR be less than or equal to what value?
A. 1.0
B. 1.2
C. 1.4
D. 1.6
C. 1.4
In clinical studies, an INR of 1.4 is considered safe for performing a percutaneous needle liver biopsy. Extrapolated from this, an INR of 1.4 is considered safe for performing neurosurgical pro- cedures. The prothrombin time should be 13.5 sec- onds or less.
With pituitary tumors, what optic chiasm position
is most associated with optic nerve compression?
A. Prefixed chiasm
B. Postfixed chiasm
C. Chiasm superior to the sella turcica
D. Neutral position chiasm
B. Postfixed chiasm
A pituitary tumor with a postfixed chiasm (located posterior to its normal position over the dorsum sellae) has an increased likelihood of com- pressing the optic nerves and causing a “pie in the sky” deficit (superotemporal quadrantanopsia) through compression of the knee of Wilbrand. Postfixed chiasms also can result in chiasmatic compression and a bitemporal hemianopsia. (A) A prefixed chiasm (located anterior to its normal position over the tuberculum sellae) is associated with optic tract compression and a homonymous hemianopsia. (C, D) The optic chiasm normally lies superior to the sella turcica.
Over 95% of vestibular schwannomas present with
progressive unilateral or asymmetric sensorineu-
ral, high-frequency hearing loss. In general, what is
considered the definition of serviceable hearing?
A. Pure tone audiogram of 40 dB or less; speech
discrimination score of at least 40%
B. Pure tone audiogram of 60 dB or less; speech
discrimination score of at least 60%
C. Pure tone audiogram of 60 dB or less; speech
discrimination score of at least 40%
D. Pure tone audiogram of 40 dB or less; speech discrimination score of at least 60%
E. American Academy of Otolaryngology–Head
and Neck Surgery (AAO-HNS) class C or D
D. Pure tone audiogram of 40 dB or less; speech discrimination score of at least 60%
Hearing is considered serviceable if the pure tone audiogram is less than or equal to 50 dB and speech discrimination is 50% of more (the “50/50” rule). American Academy of Otolaryngology-Head and Neck Surgery classifications A (30/70) and B (50/50) are considered serviceable and preservable.
A 50-year-old woman presents with an acute onset
of severe headache, bitemporal hemianopsia, and
cranial nerve III palsy. She is alert and conversant.
What is the most appropriate next step in this pa-
tient’s management?
A. Rapid administration of corticosteroids
B. Cerebral angiography
C. Administration of nimodipine
D. Obtaining an erythrocyte sedimentation rate,
C-reactive protein concentration, and blood
cultures
E. Intracranial pressure monitoring
A. Rapid administration of corticosteroids
Pituitary apoplexy can be considered a surgical emergency if it is rapidly progressive. In addition, given the compromise of the pituitary gland, prompt treatment with corticosteroids is neces- sary. (B, C) The rapid onset of a headache may suggest an aneurysmal subarachnoid hemorrhage aneurysm, and a posterior communicating artery aneurysm may produce a cranial nerve III palsy. Subarachnoid hemorrhage is not associated with bitemporal hemianopsia, however. (D) Cavernous- carotid fistulae often are associated with a pulsatile proptosis. Infectious etiologies (e.g., Tolosa-Hunt and Gradenigo syndromes) often include a painful ophthalmoplegia. (E) Increased intracranial pres- sure and uncal herniation could produce a cranial nerve III palsy, but bitemporal hemianopsia in an awake patient likely would not occur.
A 19-year-old man presents following a motor
vehicle collision complaining of lower extremity
weakness. He is found to have a thoracic spine
Chance fracture. He has full strength in his upper
extremities. He has sensation in his lower extrem-
ities and perineum, and his motor strength in his
lower extremities ranges from 4–/5 to 4/5. What
is his American Spinal Injury Association (ASIA)
impairment scale score?
A. A
B. B
C. C
D. D
E. E
D. D
The American Spinal Injury Association (ASIA) impairment scale indicates the completeness of a spinal cord injury and is different from the ASIA motor scale. ASIA A represents a complete injury without motor or sensory function below the injury level. ASIA E represents normal motor and sensory function. ASIA B is an incomplete injury with preservation of sensory but not motor func- tion below the level of injury. ASIA C is an incom- plete injury with preservation of motor function in at least half of the key muscles below the level of injury graded at less than 3/5, whereas, in ASIA D, half of the key muscles below the level of injury have at least 3/5 strength. Of note, sensory preser- vation requires that the S4 and S5 segments also be intact. The ASIA impairment scale only applies to patients who have sustained spinal cord injuries and should not be used to describe a neurologic exam otherwise.
What incomplete spinal cord injury syndrome is
associated with a poor prognosis for recovery and
dissociated sensory loss?
A. Central cord syndrome
B. Anterior cord syndrome
C. Brown-Séquard syndrome
D. Posterior cord syndrome
E. Cauda equina syndrome
B. Anterior cord syndrome
Anterior cord syndrome (anterior spinal artery syndrome) presents with paraplegia and dissoci- ated sensory loss, with loss of pain and tempera- ture sensation but with preservation of posterior column function (positional and fine touch sensa- tion). It can result from an infarct involving the anterior spinal artery. (A) Central cord syndrome presents with a greater motor deficit in the upper extremities relative to the lower extremities. It often results from a hyperextension injury in the presence of degenerative osteophytes. The over- all prognosis is that half of affected patients even- tually will be able to ambulate independently. (C) Brown-Séquard syndrome presents with disso- ciated sensory loss (loss of pain and temperature sensation with preserved light touch sensation), with ipsilateral paresis and posterior column dys- function. Of the listed syndromes, Brown-Séquard syndrome has the best prognosis, with 90% of affected patients regaining ambulatory status. (D) Posterior cord syndrome is rare. Symptoms include pain and paresthesias with minimal long tract findings. (E) Cauda equina syndrome is com- pressions of the cauda equina (not the spinal cord), resulting in urinary retention, saddle anesthesia, motor weakness, and low back pain due to the involvement of multiple nerve roots.
When placing a C2 pedicle screw, what is the tra-
jectory of the screw?
A. Superior and medial
B. Superior and lateral
C. Inferior and medial
D. Inferior and lateral
E. Parallel to the spinous process
A. Superior and medial
The pars interarticularis and pedicle of the C2 vertebral body, from posterior to anterior, are ori- ented superiorly and medially. The entry point for C2 pedicle screw placement is 3 to 4 mm superior to the inferior margin of the C2 inferior facet and at the midpoint mediolaterally with a trajectory of 20 to 30 degrees medially and 25 degrees supe- riorly. The vertebral artery courses laterally as it passes through the C2 transverse foramen so that the more superior the screw is placed, the far- ther away from the vertebral artery the screw is located.
What is a relative contraindication for the place-
ment of an anterior odontoid screw that may make
surgery technically very difficult?
A. Type 2 odontoid fracture
B. Combined 5-mm overhang of the lateral masses
of C1 on C2
C. Acute fracture
D. Reducible fracture
E. Barrel chest
E. Barrel chest
Relative contraindications for odontoid screw placement include a type 3 odontoid fracture, large fracture gaps, irreducible fractures, chronic fractures, pathological fractures, and fracture lines that are oblique to the frontal plane. Odontoid screws are useful for acute, type 2 fractures with intact ligaments but can be difficult to place in patients with short, thick necks or barrel chests. This relative contraindication sometimes can be circumvented with appropriate instrumentation. (B) The most significant absolute contraindication for odontoid screw placement is the disruption of the transverse atlantal ligament as seen on MRI or indirectly if the sum of the overhang of the lat- eral masses of C1 on C2 exceeds 7 mm. This latter assessment is known as the rule of Spence.
A patient presents in the emergency room with a
cervical spine fracture and the following radio-
graphic findings: a triangular bone fragment frac-
tured off the anterior inferior vertebral body,
retrolisthesis of the caudal vertebrae, and disrup-
tion of the facet joints and the disk space. What
type of fracture is suspected?
A. Avulsion fracture
B. Clay-shoveler fracture
C. Jefferson fracture
D. Teardrop fracture
E. Locked facets
D. Teardrop fracture
Teardrop fractures are compression/flexion injuries that often are unstable. They usually pre- sent with chip fractures and retrolisthesis, sagittally oriented fractures, a kyphotic deformity, facet/disk space disruption, and soft tissue swelling. (A) Avul- sion fractures present with chip fractures as a result of anterior longitudinal ligament traction on the fractured bone (a hyperextension injury). There often is no misalignment, body fracture, or poste- rior element or disk disruption. (B) A clay-shoveler fracture is an avulsion of the C7 spinous process. (C) Jefferson fractures are four-point burst frac- tures of the C1 ring. They are classified as unstable but often are treated with orthosis; they typically present without neurologic deficits. (E) Locked facets result from distraction/flexion injuries and often present with anterolisthesis.
A patient presents after a significant fall from a
ladder with an L2 burst fracture that has a 70% loss
of height, 50% canal stenosis due to retropulsion,
and 15 degrees of angulation. How would you re-
duce this fracture with ligamentotaxis?
A. Removing ligaments such as the ligamentum
flavum that would allow for easier manipula-
tion of the fracture
B. Distracting pedicle screws to reduce indirectly the retropulsed segment by putting tension on the posterior longitudinal ligament
C. Compressing pedicle screws to reduce the ret-
ropulsed fragment by releasing tension on the
posterior longitudinal ligament
D. Placing a strut or cage to reduce the loss of
height of the vertebral body
E. Positioning the patient to utilize the anterior
longitudinal ligament to reduce the kyphotic
angulation associated with the fracture
B. Distracting pedicle screws to reduce indirectly the retropulsed segment by putting tension on the posterior longitudinal ligament
Ligamentotaxis is the theory for the practice that is used by some physicians to “pull” bony frag- ments that are in the central canal back to their normal positions (assuming the posterior longitu- dinal ligament is intact). Typically, this technique is used with a distraction technique such as with pedicle screws. (A, C–E) These techniques are uti- lized in deformity and spinal trauma surgery but are not considered ligamentotaxis.
In what zone is a sacral fracture that occurs in the
region of the sacral foramina?
A. Zone 1
B. Zone 2
C. Zone 3 (vertical)
D. Zone 4 (transverse)
E. Zone 5
B. Zone 2
Sacral zone 2 fractures occur vertically, ascend the sacral foramina, and may cause unilateral L5, S1, or S2 root injuries (including sciatica). (A) Sacral zone 1 fractures occur at the sacral ala and may be associated with an L5 root injury. (C) Sacral zone 3 fractures occur within the sacral canal and can cause sphincter dysfunction with bilateral nerve root injuries and saddle anesthesia. Fractures extending vertically in zone 3 are associated with pelvic ring fractures. (D) Transverse sacral frac- tures sometimes are classified as zone 4 injuries and occur from falls. They can produce severe neu- rologic deficits. (E) There is no zone 5.
Fisher grade 3 is differentiated from Fisher grade 2
for aneurysmal subarachnoid hemorrhage by what
characteristic?
A. Greater than 1 mm of blood
B. Presence of hydrocephalus
C. Intracerebral or intraventricular clot
D. Presence of vasospasm
E. Greater than 1 cm of blood
A. Greater than 1 mm of blood
The Fisher grading system is effective in deter- mining the risk of vasospasm associated with an- eurysmal subarachnoid hemorrhage according to the amount of blood seen on CT. Grade 1 is without subarachnoid hemorrhage. Grade 2 indicates sub- arachnoid hemorrhage less than 1 mm in thick- ness. Grade 3 indicates a localized clot or layer of subarachnoid hemorrhage at least 1 mm in thick- ness. (C) Grade 4 indicates intraparenchymal or intraventricular hemorrhage.
A 37-year-old man presents with a sudden onset
of the “worst headache of my life.” The CT shows
intraventricular hemorrhage that you suspect re-
sulted from hemorrhage entering through the lam-
ina terminalis. You are suspicious of an aneurysm
at what location?
A. Middle cerebral artery bifurcation
B. Posterior communicating artery
C. Internal carotid artery terminus
D. Anterior communicating artery
E. Basilar artery tip
D. Anterior communicating artery
Anterior communicating artery aneurysms often present with blood in the anterior interhemi- spheric fissure, a hematoma in the gyrus rectus, and intraventricular hemorrhage in the third ven- tricle, which is thought to reach the ventricles through the lamina terminalis.
A patient presents with subacute bacterial endo-
carditis. Evaluation and workup includes a CT an-
giogram followed by a cerebral angiogram that
demonstrates two small aneurysms on distal left
middle cerebral artery branches. What treatment
modality is indicated?
A. Endovascular coiling
B. Surgical clipping
C. Antibiotics and serial imaging
D. Observation
C. Antibiotics and serial imaging
Mycotic aneurysms are common in bacterial endocarditis and occur in 3 to 15% of patients with this diagnosis. The aneurysms are found most commonly in the distal middle cerebral artery branches. At least 20% of patients have mul- tiple aneurysms, and there is an association with immunocompromised and intravenous drug abuse patients. Treatment consists of antibiotic therapy, as these aneurysms are friable and not easily amenable to surgical or endovascular treatments. Serial angiograms are used to follow the resolu- tion of mycotic aneurysms. Surgical clipping may be indicated in patients with subarachnoid hemor- rhage, increasing aneurysm size despite antibiotic treatment, failure of antibiotics to resolve the aneurysm, and focal deficits.
Following the standard of care, what role does
brachytherapy play as an adjunctive treatment for
high-grade gliomas?
A. Brachytherapy is a viable alternative to whole
brain radiation.
B. Brachytherapy is superior to stereotactic
radiosurgery.
C. Brachytherapy has no role as an adjuvant to whole brain radiation.
D. Brachytherapy can be useful in addition to
whole brain radiation.
E. Brachytherapy can substitute for whole brain
radiation.
C. Brachytherapy has no role as an adjuvant to whole brain radiation.
Brachytherapy provides no significant overall
survival or quality-of-life benefits when compared
with whole brain radiation and should not be used
alone or as an adjuvant therapy for high-grade gliomas. This is due to the diffuse nature of gliomas
and the side effects of brachytherapy.
Following resection of a low-grade oligodendrogli-
oma, what is the next step in adjuvant therapy?
A. Intravenous chemotherapy
B. Focused radiation
C. Whole brain radiation
D. Intrathecal chemotherapy
A. Intravenous chemotherapy
Following resection of a low-grade oligodendroglioma, chemotherapy is the mainstay of adjuvant
therapy, with radiation reserved for higher grade
lesions due to their aggressiveness and more diffuse characteristics. The typical chemotherapy protocol of procarbazine, CCNU, and vincristine is
given intravenously and not intrathecally.
What is the complication rate for shunting a
patient with normal pressure hydrocephalus?
A. 5 to 10%
B. 10 to 25%
C. 25 to 40%
D. 40 to 55%
C. 25 to 40%
Complications rates are high when shunting
patients with normal pressure hydrocephalus, likely
in part due to the advanced average age of the
patients with the condition. Complications include
subdural hematomas, shunt infections, intracranial
hemorrhages, seizures, and shunt malfunctions.
As for the symptoms of normal pressure hydrocephalus, incontinence followed by gait abnormalities is the symptom most likely to improve with
shunting. Dementia is the symptom least likely to
improve.
A woman is referred to your office for symptoms
consistent with carpal tunnel syndrome. She has
had a nerve conduction study showing that the
proximal median nerve latency is shorter than the
distal median nerve latency. What is the explana-
tion for this finding?
A. Poor quality/erroneous nerve conduction study
B. Lesion of the proximal median nerve
C. Presence of a Martin-Gruber anastomosis
D. Marinacci syndrome
E. Diabetic neuropathy
C. Presence of a Martin-Gruber anastomosis
A Martin-Gruber median to ulnar nerve anastomosis occurs in 15 to 30% of individuals and consists of a communicating nerve branch between
median and ulnar nerves. A clue to the presence of
a Martin-Gruber anastomosis with carpal tunnel
syndrome is a faster than expected conduction velocity in the median nerve in the forearm. In severe
carpal tunnel syndrome, because nerve fibers are
passing around the carpal ligament through the
ulnar nerve, antecubital fossa stimulation may
result in thenar stimulation faster than with stimulation at the wrist (there also will be a positive
deflection). (D) Marinacci syndrome is a “reverse”
Martin-Gruber anastomosis characterized by an
ulnar to median nerve anastomosis that can cause
carpal tunnel syndrome from an ulnar nerve compression at the elbow.
A 17-year-old boy is brought to the emergency
room following a motor vehicle collision with mul-
tiple fatalities. He is alert, awake, and oriented. He
denies neck pain, has no midline tenderness, and
does not have any other injuries. The neurologic
exam is unremarkable. He has not used alcohol or
drugs. What is the minimum radiographic study
needed to clear the cervical spine?
A. Radiographs are not indicated
B. Upright lateral and AP X-rays
C. Flexion-extension X-rays
D. Lateral and AP X-rays with CT imaging of areas
that are suspicious or not easily seen on plain
films
E. Thin-cut axial CT scan from the occiput to T1
with sagittal and coronal reconstructions
A. Radiographs are not indicated
There are five NEXUS criteria to indicate the
need for cervical spine imaging: midline cervical
tenderness, focal neurologic deficits, altered level
of consciousness, intoxication, and painful distracting injuries. If these are all negative, radiographic
studies are not indicated. In trauma patients who
are symptomatic, obtunded, or have an unreliable
neurologic exam, a thin-cut axial CT scan is indicated with reconstructions.
A 63-year-old diabetic man with a remote history
of vertebral osteomyelitis presents to the hospital
with low back pain and pain down the anterior
part of the thigh for the past 3 weeks. Neuro-
logic exam is unremarkable. MRI suggests a psoas
and epidural abscess without severe compres-
sion. What is the next appropriate step in this pa-
tient’s management?
A. Discharge home on oral antibiotics with
follow-up with an infectious disease specialist.
B. Admit to the floor, place on antibiotics, and
consult interventional radiology for culture
and biopsy of the epidural abscess.
C. Consult interventional radiology for culture
and biopsy of the epidural space prior to start-
ing antibiotics.
D. Admit to the floor, obtain blood cultures, and
consult interventional radiology for biopsy of
the psoas abscess prior to administering anti-
biotics (if the biopsy can be done in a timely manner).
E. Perform a decompressive laminectomy with
evacuation of the abscess.
D. Admit to the floor, obtain blood cultures, and
consult interventional radiology for biopsy of
the psoas abscess prior to administering anti-
biotics (if the biopsy can be done in a timely manner).
Medical management of patients with epidural
abscesses is preferred when there are long-standing
symptoms without progressive neurologic deficits,
when imaging is not worrisome for severe compression, in patients with prohibitive operative risk
factors, and in patients with complete paralysis for
longer than 3 days. Epidural biopsy is not recommended; however, disk space/vertebral body biopsy
is a reasonable option.
An 82-year-old woman presents to the neurosur-
gery clinic with typical trigeminal neuralgia. She
has substantial medical comorbidities and would
like to avoid surgery. The patient opts for stereo-
tactic radiosurgery. What factor would predict a
favorable outcome?
A. Absence of atypical pain
B. Using a radiation dose less than 60 Gy
C. Prior successful surgical microvascular
decompression
D. Decreased sensation in the affected nerve
prior to treatment
E. Trigeminal neuralgia related to multiple
sclerosis
A. Absence of atypical pain
Absence of atypical pain is a favorable prognosticator in surgical and radiosurgical candidates for
trigeminal neuralgia treatment. Other favorable
factors include using higher radiation doses, a lack
of previous trigeminal neuralgia operations, and
normal pretreatment sensory function.
What is the most effective surgical option for the
treatment of glossopharyngeal neuralgia in the
absence of vascular compression?
A. Cranial nerve IX rhizotomy alone
B. Cranial nerve X rhizotomy alone
C. Cranial nerve IX rhizotomy with sectioning the upper one third of cranial nerve X
D. Extracranial nerve ablation of cranial nerve IX
E. Cranial nerve XI rhizotomy alone
C. Cranial nerve IX rhizotomy with sectioning the upper one third of cranial nerve X
When an offending vessel (classically the posterior inferior cerebellar artery) is seen compressing
cranial nerve IX, microvascular decompression
(MVD) is the preferred treatment choice. During
an exploration that fails to reveal vascular compression of the nerve, the most effective treatment
includes sectioning of cranial nerve IX and the
upper rootlets of cranial nerve X. Studies suggested
that there is a higher rate of pain recurrence when
both nerves are not sectioned simultaneously. The
risks of sectioning cranial nerve X may include
significant bradycardia, dysphagia, and voice
hoarseness.
A teenager suffering from a defect in his L5 pars
interarticularis as a result of an insufficiency frac-
ture of the pars can be characterized as having
what type of spondylolisthesis?
A. Dysplastic
B. Isthmic
C. Degenerative
D. Traumatic
E. Pathological
B. Isthmic
There are five types of spondylolisthesis: type 1,
dysplastic, is congenital and related to spina bifida;
type 2, isthmic (spondylolytic), is a result of pars
insufficiency fractures, an elongated pars from
repetitive fractures/healing, or acute fractures;
type 3, degenerative, usually occurs at L4/L5 without a break in the pars interarticularis; type 4,
traumatic, is due to a posterior element fracture
(other than the pars); type 5, pathological, is secondary to a tumor or bone disorder.
You perform a stereotactic-guided biopsy of a tha-
lamic lesion. You notice bleeding from the cannula.
What is the next step?
A. Perform an emergent craniotomy and
exploration.
B. Immediately abort the procedure, and obtain
a CT.
C. Abort the procedure, wake the patient, and
obtain a neurologic exam.
D. Elevate the head of the bed, decrease the blood
pressure, and irrigate the cannula.
E. Insert a Fogarty catheter into the cannula,
inflate the balloon, and obtain a CT.
D. Elevate the head of the bed, decrease the blood
pressure, and irrigate the cannula.
The main complication related to a blind, stereotactic-guided biopsy is hemorrhage. Most bleeding
is capillary or venous, and can be managed by
conventional methods of cannula irrigation, head
elevation, and induced hypotension with a systolic
blood pressure around 90 mm Hg. Nevertheless,
craniotomy and clot evacuation may be necessary
to obtain hemostasis in refractory bleeding
What is the most common location of mycotic
aneurysms?
A. Distal middle cerebral artery branches
B. Proximal anterior cerebral artery
C. Distal anterior cerebral artery
D. Basilar tip
E. Posterior inferior cerebellar artery
A. Distal middle cerebral artery branches
Mycotic aneurysms occur in distal middle cerebral artery branches 75 to 80% of the time. They
also occur in distal anterior cerebral artery branches
less often. Twenty percent of patients with mycotic
aneurysms have multiple aneurysms, and mycotic
aneurysms may occur in up to 15% of patients with
subacute bacterial endocarditis. The most common pathogen is Streptococcus viridans
A 35-year-old woman presents with spontaneous
neck pain. A noncontrast head CT demonstrates
subarachnoid hemorrhage, and an angiogram
reveals a lesion suspicious for an intradural ver-
tebral artery dissection. What is the appropriate
treatment for this finding?
A. Observation if asymptomatic
B. Immediate heparinization followed by oral
anticoagulation
C. Immediate surgery or endovascular treatment
D. Delayed surgery to allow for swelling
resolution
E. Nonoperative treatment followed by a delayed
angiogram in 5 to 7 days to assess healing
C. Immediate surgery or endovascular treatment
Vertebral dissections can lead to pain, transient
ischemic attacks, strokes, and subarachnoid hemorrhage. Rebleeding is common and occurs in 30%
of those with subarachnoid hemorrhage. In dissections without hemorrhage or large ischemic strokes,
heparin followed by oral anticoagulation should
be started immediately. Surgery (hunterian ligation following a balloon test occlusion study), clipping with or without bypass, graft placement or
wrapping, and endovascular treatment (stents/
occlusion/angioplasty) are the treatments of choice
for patients presenting with subarachnoid hemorrhage, extradural lesions that progress, or symptoms that persist despite medical therapy.
A 32-year-old man presents with slurred speech
and a hypoglossal palsy. He reported that he was
involved in a motor vehicle collision 3 weeks prior
for which he did not pursue medical evaluation. He
reports that he has had neck pain since the acci-
dent. What is the suspected diagnosis?
A. Atlanto-occipital dislocation
B. Vertebral artery dissection with stroke
C. Odontoid fracture
D. Clival fracture
E. Condyle fracture
E. Condyle fracture
Condyle fractures are not common but can present with delayed cranial nerve palsies, especially a
hypoglossal palsy due to the fact that the hypoglossal canals are intimate with the occipital condyles. Brainstem findings also occasionally occur.
Treatment is with a rigid collar unless the occipital
to C1 interval is more than 2 mm, at which point
surgical stabilization is required.
A 43-year-old woman presents to the neurosur-
gery clinic complaining of hand clumsiness. A
neurologic exam reveals wasting and weakness of
the abductor pollicis brevis and hand intrinsics.
There is sensory loss over the medial forearm, but
sensation in the hand is normal. According to the
above findings, what is the next appropriate test
for diagnosis?
A. MRI of the brain
B. Cerebrospinal fluid studies
C. Chest radiograph
D. MRI of the cervical spine
E. Cervical spine radiographs with oblique and apical lordotic views
E. Cervical spine radiographs with oblique and apical lordotic views
Neurologic thoracic outlet syndrome is rare and
usually affects women. One cause is a constricting
band that originates from the first rib or an elongated C7 transverse process that causes compression of the C8 and T1 nerve roots, proximal trunk
of the brachial plexus, or median cord. Sensory
changes often spare the median nerve (which
passes through the upper and middle trunks of the
brachial plexus) but are seen in the lower trunk
(C8 and T1 nerve roots). Electromyography in thoracic outlet syndrome is unreliable but may have
positive findings if sensory nerve action potentials
are analyzed in the medial antebrachial cutaneous
nerve. (D) MRIs of the cervical spine are poor for
detecting bony abnormalities in thoracic outlet
syndrome but may rule out pathologies that mimic
thoracic outlet syndrome such as cervical disk
herniation.
What tumor often arises from the “roof” of the
fourth ventricle?
A. Ependymoma
B. Juvenile pilocytic astrocytoma
C. Brainstem glioma
D. Choroid plexus papilloma
E. Medulloblastoma
E. Medulloblastoma
Medulloblastomas often arise from the cerebellar vermis close to the fastigium near the posterior
medullary velum (the roof of the fourth ventricle).
(A) Ependymomas often arise from the floor of the
fourth ventricle. (B) Juvenile pilocytic astrocytomas (JPAs) can occur in the optic/hypothalamic
areas, brainstem, cerebellum, and spinal cord. Cerebellar JPAs often are hemispheric. (C) Brainstem
gliomas can be diffuse, cervicomedullary, and focal
or dorsally exophytic. They do not arise from the
roof of the fourth ventricle. (D) Choroid plexus
papillomas commonly are found in the lateral ventricles and arise from the choroid plexus.
A 38-year-old man presents with seizures, and
workup reveals an arteriovenous malformation
that is 6.4 cm in size, involves the posterior fronto-
parietal and occipital lobes, and drains into the
galenic system. What is the preferred treatment
option for this lesion?
A. Embolization alone
B. Stereotactic radiosurgery alone
C. Surgical resection
D. Observation
E. Embolization and stereotactic radiosurgery
D. Observation
The Spetzler-Martin arteriovenous malformation (AVM) grading system is based on AVM size (1 to 3 points allocated for an < 3 cm, 3 to 6 cm, and > 6 cm, respectively), eloquence of adjacent brain
(eloquent, 1 point; non-eloquent, 0 points), and
venous drainage (deep, 1 point; superficial, 0 points).
The natural history of the disease process (3 to 4%
risk of hemorrhage yearly) must be considered with
the risk of treatment. Grade 4 and 5 AVMs often
are treated with serial scans and observation. The
described AVM is grade 5.
After elective clipping of an unruptured anterior
communicating artery aneurysm, the patient wakes
up with dysarthria and contralateral paresis of his
face and arm. What vessel likely is incorporated
into the aneurysm clip?
A. Anterior choroidal artery
B. Recurrent artery of Heubner
C. Middle cerebral artery
D. Distal anterior cerebral artery
B. Recurrent artery of Heubner
The Recurrent artery of Heubner typically originates from the proximal A2 segment of the anterior
cerebral artery. It supplies the head of the caudate
nucleus, anterior limb of the internal capsule,
anterior putamen, and globus pallidus. Unilateral
injury results in contralateral face and arm weakness. Bilateral injury results in akinetic mutism.
(A) The anterior choroidal artery supplies the posterior limb of the internal capsule and the lateral
geniculate body of the thalamus. Occlusion results
in contralateral hemiplegia, hemianesthesia, and
homonymous visual field deficits. (C) Injury to the
middle cerebral artery results in an infarct causing
contralateral hemiparesis and neglect. (D) Distal
anterior cerebral artery compromise results in
infarcts in the paramedian cortex.
The most common primary, intra-axial posterior
fossa tumor in adults is associated with what
condition?
A. Smoking
B. Tumor suppressor gene inactivation on chro-
mosome 9q34
C. Tumor suppressor gene inactivation on chro-
mosome 7q21
D. Tumor suppressor gene inactivation on chro-
mosome 3p25
D. Tumor suppressor gene inactivation on chro-
mosome 3p25
The most common posterior fossa tumor in
adults is metastases (most often from lung cancer); however, the most common primary, intraaxial posterior fossa tumor is hemangioblastoma.
Von Hippel–Lindau syndrome is associated with
30% of cerebellar hemangioblastomas and is an
autosomal dominant, inherited disease found on
chromosome 3p25. (A) Smoking is most associated
with metastatic lesions. (B) Tumor suppressor
gene inactivation on chromosome 9q34 is associated with tuberous sclerosis. (C) Tumor suppressor
gene inactivation on chromosome 7q21 is associated with a familial form of cavernomas.
A 21-year-old man presents with a brachial plexus
avulsion type injury. What is the recommended
treatment option?
A. Periodic electromyography/nerve conduction studies starting 3 to 12 weeks following the injury with consideration of surgical neu-rotization at 3 to 6 months if there is no improvement
B. Periodic electromyography/nerve conduction
studies starting 3 to 12 weeks following the
injury with consideration of surgical neu-
rolysis at 3 to 6 months if there is no
improvement
C. Periodic electromyography/nerve conduction
studies starting 3 to 12 weeks following the
injury with consideration of a spinal cord
stimulator if pain remains after 3 to 6 months
D. Exploration and surgical repair within 3 days
E. Exploration at 2 to 3 weeks
A. Periodic electromyography/nerve conduction studies starting 3 to 12 weeks following the injury with consideration of surgical neu-rotization at 3 to 6 months if there is no improvement
Surgical treatment of peripheral nerve injuries
can be defined by the “rule of 3’s.” Sharp lacerations are explored within 3 days, penetrating injuries are explored in 2 to 3 weeks, and gunshot
wounds and traction injuries are explored in 3 to 6
months. An avulsion (traction injury) occurs when
a root is pulled from the spinal cord with no chance
of reinnervation. Because this injury happens proximal to the dorsal root ganglia, synaptic action potentials are characteristically normal. Neurolysis
(lysis of scar tissue) is not successful for lesions
that are not in continuity. A dorsal root entry zone
(DREZ) lesioning procedure is the procedure of
choice for chronic pain for plexus avulsion injuries.
Only neurotization (nerve transfers) can restore
downstream nerve/muscle/sensory function.
This diagram attempts to define which parameter?
A. Sacral slope
B. Pelvic tilt
C. Pelvic incidence
D. Sagittal vertical axis
E. T1 tilt
B. Pelvic tilt
Pelvic tilt is the angle measurement between a
line drawn from the midpoint of the S1 end plate
to the midpoint of the femoral head and a vertical
line from the femoral axis. It represents a “compensatory mechanism”; thus, patients with kyphotic
deformities may use retropulsion to keep their
head aligned with the horizon. Increasing retroversion to accommodate for increasing kyphosis
will increase the pelvic tilt. (A) Sacral slope is the
measurement of the sacral slant, and is the angle
between a line parallel to the sacral end plate and
the horizon. (C) Pelvic incidence = Pelvic tilt +
Sacral slope. Sacral slope approximates the pelvic
incidence. Pelvic incidence is the angle measurement between the line from the mid-femoral head
to the midpoint of the sacral end plate and a line
perpendicular to the sacral end plate. This parameter does not change.
A 40-year-old man presented to the emergency
room with complaints of left-hand numbness. Fur-
ther workup revealed the lesion on MRI that is
shown in this image. He was taken to surgery for
resection. Postoperatively, the patient awoke with
a dense left hemiparesis. Supplementary motor
area (SMA) syndrome was suspected. What is the
expected prognosis of SMA syndrome?
A. Permanent left hemiparesis/hemiplegia
B. Temporary decreased spontaneous and volun-
tary movements of the left upper and lower
extremities with spontaneous recovery
C. Permanent decreased spontaneous and volun-
tary movements of the left upper and lower
extremities with aphasia without spontaneous
recovery
D. Temporary left lower extremity paresis with
loss of muscle tone with spontaneous recovery
E. Temporary left upper and lower extremity
paresis and hemisensory loss with spontaneous
recovery
B. Temporary decreased spontaneous and volun-
tary movements of the left upper and lower
extremities with spontaneous recovery
Supplementary motor area (SMA) syndrome
characteristically causes a contralateral apraxia and
loss of spontaneous/voluntary movements, with
preservation of muscle tone and strength. It can
result in mutism occurring more often when the
dominant SMA is involved. Reflexes often are preserved. Classically, there is spontaneous recovery
over weeks to months, leaving only a long-term
deficit in alternating bimanual movements.
What is the benign lesion seen in this intraopera-
tive image with a gross pearly white appearance
A. Epidermoid cyst
B. Dermoid cyst
C. Lipoma
D. Adamantinomatous craniopharyngioma
A. Epidermoid cyst
Epidermoid tumors are thin walled, with a characteristic smooth, pearly white appearance on gross
examination. (B) Dermoid cysts are thick walled,
with greasy pilosebaceous contents. (C) Lipomas
have a yellow, fatty gross appearance. (D) Adamantinomatous craniopharyngiomas are partly cystic
with white speckled keratin nodules.
This image shows what type of intracranial lesion?
A. Arachnoid cyst
B. Epidermoid cyst
C. Dermoid cyst
D. Neurenteric cyst
B. Epidermoid cyst
Epidermoid cysts appear as well-defined, often
relatively round masses with thin, pearly white
walls. The cysts contain a dense, keratinous substance. (A) Arachnoid cysts are thin walled (often
translucent), and contain clear fluid similar to the
makeup of cerebrospinal fluid. (C) Dermoid cysts
(mature teratomas) are thick walled, and contain a
variety of mature tissues, including hair, sebaceous
glands, and skin. (E) Neurenteric cysts are thick
walled, and often have variable contents but typically contain a thick, creamy, mucin-like substance.
What recess is indicated by the arrow in this image?
A. Opticocarotid cistern
B. Carotico-oculomotor cistern
C. Interpeduncular cistern
D. Lamina terminalis
E. Cerebellopontine angle
A. Opticocarotid cistern
The image accompanying the question illustrates
a left-sided approach that may be seen with a pterional craniotomy. The carotid artery is seen lateral to the optic nerve. The internal carotid artery
bifurcation is seen as the anterior cerebral artery
A1 segment crosses the optic nerve in the five
o’clock position of the image. The middle cerebral
artery M1 segment is found at the seven o’clock
position. The arrow points to the opticocarotid
recess. (B) The carotico-oculomotor membrane is
bound superiorly by the superior dural ring and
inferiorly by the inferior dural ring and is intimately related to cranial nerve III.
What is the most common location for the “pearly”
tumor shown in this image?
A. As part of the dural along the cerebral
convexities
B. Cerebellopontine angle
C. Thalamus
D. Extra-calvarial
E. Pineal gland
B. Cerebellopontine angle
Epidermoid cysts occur in the cerebellopontine
angle in 40 to 50% of cases and are the third most
common cerebellopontine angle tumor. They also
are found in the fourth ventricle and sellar region.
Less common locations are the cerebral hemispheres, brainstem, and extradural spine/skull.
