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1. General Principles & Basic Science MCQs

Practice Set 16 of 789

This practice set contains high-yield board review questions covering key concepts in 1. General Principles & Basic Science. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 301

Topic: Biomechanics & Biomaterials

The polymethylmethacrylate (PMMA) utilized in percutaneous vertebroplasty has which of the following distinct properties when compared to standard joint arthroplasty cement?

. Significantly higher initial viscosity
. Decreased radiopacity to prevent imaging artifacts
. Extended working time
. Higher exothermic reaction temperature
. Increased ultimate tensile strength

Correct Answer & Explanation

. Extended working time

Explanation

PMMA formulated for vertebral augmentation is modified to have an extended working time and lower initial viscosity, allowing safe and precise delivery through narrow cannulas. It is also formulated with high radiopacity (usually barium or tungsten) for mandatory fluoroscopic visualization.

Question 302

Topic: 1. General Principles & Basic Science
What is an absolute contraindication to performing a percutaneous vertebroplasty for an osteoporotic compression fracture?
. Fracture age greater than 6 weeks
. Concurrent use of bisphosphonates
. Osteomyelitis at the targeted vertebral level
. Greater than 50% loss of vertebral body height
. Presence of an intravertebral vacuum cleft (Kรผmmell disease)

Correct Answer & Explanation

. Osteomyelitis at the targeted vertebral level

Explanation

Absolute contraindications to vertebroplasty include active local or systemic infection (e.g., osteomyelitis), uncorrectable coagulopathy, and known allergy to bone cement. A vacuum cleft is actually an indication that vertebroplasty may be highly successful in stabilizing a nonunion.

Question 303

Topic: Biology, Genetics & Bone Healing

A 75-year-old female with an acute osteoporotic compression fracture is prescribed an intranasal medication that provides both antiresorptive effects and analgesic properties for acute bone pain. What is the mechanism of action of this medication?

. Recombinant parathyroid hormone analog
. Inhibition of osteoclast-mediated bone resorption via calcitonin receptors
. Monoclonal antibody against RANKL
. Selective estrogen receptor modulation
. Inhibition of farnesyl pyrophosphate synthase

Correct Answer & Explanation

. Inhibition of osteoclast-mediated bone resorption via calcitonin receptors

Explanation

Intranasal calcitonin inhibits osteoclast activity and has a well-documented analgesic effect for acute pain associated with osteoporotic vertebral compression fractures. It is particularly useful in the acute phase of the injury.

Question 304

Topic: 1. General Principles & Basic Science

A 68-year-old female undergoes a multilevel vertebroplasty. During the procedure, the patient suddenly develops tachycardia, hypotension, and hypoxia. What is the most likely cause?

. Cement leakage into the spinal canal
. Polymethylmethacrylate (PMMA) pulmonary embolism
. Allergic reaction to local anesthetic
. Acute myocardial infarction
. Epidural hematoma

Correct Answer & Explanation

. Polymethylmethacrylate (PMMA) pulmonary embolism

Explanation

PMMA pulmonary embolism is a rare but potentially fatal complication of vertebroplasty, caused by the migration of liquid cement into the paravertebral venous plexus and subsequently to the pulmonary vasculature. Immediate cardiopulmonary support is required.

Question 305

Topic: Biology, Genetics & Bone Healing

A patient with a history of a distal radius fragility fracture sustains a vertebral compression fracture. Bone mineral density (BMD) testing reveals a T-score of -3.0. According to WHO criteria, this strictly defines:

. Normal bone density
. Osteopenia
. Osteomalacia
. Osteoporosis
. Severe (established) osteoporosis

Correct Answer & Explanation

. Severe (established) osteoporosis

Explanation

According to the WHO, a T-score of -2.5 or lower defines osteoporosis. The presence of one or more documented fragility fractures in combination with a T-score of -2.5 or lower classifies the condition as severe (or established) osteoporosis.

Question 306

Topic: Biology, Genetics & Bone Healing

Teriparatide is being considered for a patient with severe osteoporosis and multiple painful compression fractures. Which of the following is a recognized absolute contraindication to its use?

. Previous long-term treatment with oral bisphosphonates
. History of deep vein thrombosis or pulmonary embolism
. Prior radiation therapy to the skeleton
. Concomitant daily use of calcium and vitamin D supplements
. Uncontrolled Type 2 diabetes mellitus

Correct Answer & Explanation

. Prior radiation therapy to the skeleton

Explanation

Teriparatide (recombinant PTH) is an anabolic agent. It is contraindicated in patients with prior skeletal radiation therapy, Paget's disease of bone, or unexplained elevated alkaline phosphatase due to a theoretical increased risk of developing osteosarcoma.

Question 307

Topic: 1. General Principles & Basic Science
When comparing conservative treatment to percutaneous vertebroplasty for acute osteoporotic vertebral compression fractures, key randomized blinded controlled trials (e.g., INVEST and Buchbinder trials) have historically demonstrated:
. Vertebroplasty significantly and predictably decreases mortality at 1 year
. Vertebroplasty provides no significant benefit in pain relief or function over a sham procedure at short-term and long-term follow-up
. Conservative treatment inherently leads to significantly higher rates of permanent paralysis
. Vertebroplasty locally restores bone mineral density to age-matched normal levels
. Conservative treatment requires mandatory strict bed rest for a minimum of 6 weeks

Correct Answer & Explanation

. Vertebroplasty provides no significant benefit in pain relief or function over a sham procedure at short-term and long-term follow-up

Explanation

Landmark blinded randomized trials (such as those by Buchbinder and Kallmes/INVEST) demonstrated that vertebroplasty did not provide statistically significant improvements in pain or function compared to a sham (placebo) procedure, sparking considerable debate regarding its routine use.

Question 308

Topic: 1. General Principles & Basic Science

In which of the following nerve roots is compression neuropathy common in cervical spondylosis:

. C 3 and C 4
. C 4 and C 5
. C 5 and C 6
. C 6 and C 7
. C 7 and C 8

Correct Answer & Explanation

. C 6 and C 7

Explanation

The nerve roots that are most commonly affected in cervical spondylosis are C6 and C7, secondary to degenerative changes in the C 5-C 6 and C 6-C 7 nerve roots. Patients may have specific dermatomal pain or pain that is diffuse and poorly localized.

Question 309

Topic: Physiology & Rehabilitation

A patient is brought to the emergency department after a motor vehicle collision. Neurological examination reveals loss of motor function, pain, and temperature sensation below the T6 level, but proprioception and vibratory sense are intact. Which of the following spinal cord syndromes is the most likely diagnosis?

. Central cord syndrome
. Brown-Sequard syndrome
. Anterior cord syndrome
. Posterior cord syndrome
. Conus medullaris syndrome

Correct Answer & Explanation

. Anterior cord syndrome

Explanation

Anterior cord syndrome is characterized by loss of motor function, pain, and temperature sensation below the injury level due to damage to the anterior two-thirds of the spinal cord. Proprioception and vibration remain intact as the dorsal columns are spared.

Question 310

Topic: Physiology & Rehabilitation

A penetrating stab wound to the right side of the T8 spinal cord produces a Brown-Sequard syndrome. Which of the following clinical deficits will be observed?

. Right-sided loss of pain and temperature, left-sided loss of motor function
. Right-sided loss of motor and proprioception, left-sided loss of pain and temperature
. Bilateral loss of pain and temperature with preserved motor function
. Left-sided loss of motor and proprioception, right-sided loss of pain and temperature
. Bilateral motor loss with right-sided loss of pain and temperature

Correct Answer & Explanation

. Right-sided loss of motor and proprioception, left-sided loss of pain and temperature

Explanation

Brown-Sequard syndrome causes ipsilateral loss of motor function (corticospinal tract) and proprioception/vibration (dorsal columns), and contralateral loss of pain and temperature sensation (spinothalamic tract) which crosses 1-2 levels above the entry site.

Question 311

Topic: Physiology & Rehabilitation
A 45-year-old male involved in a high-speed collision presents with paraplegia, loss of pain and temperature sensation in his lower extremities, but preserved vibration and proprioception. Which spinal cord syndrome does this describe?
. Central cord syndrome
. Anterior cord syndrome
. Brown-Sรฉquard syndrome
. Posterior cord syndrome
. Conus medullaris syndrome

Correct Answer & Explanation

. Anterior cord syndrome

Explanation

Anterior cord syndrome typically results from flexion injuries or anterior spinal artery compromise. It causes motor, pain, and temperature loss below the lesion, with preserved dorsal column function (proprioception and vibration).

Question 312

Topic: Infection, Pharmacology & VTE

A patient with a T4 complete spinal cord injury suddenly develops a severe, pounding headache, profound diaphoresis above the level of injury, and severe hypertension. What is the most common precipitating cause of this condition?

. Bladder distension
. Deep vein thrombosis
. Pulmonary embolism
. Acute myocardial infarction

Correct Answer & Explanation

. Bladder distension

Explanation

This presentation describes autonomic dysreflexia, which occurs in patients with spinal cord injuries above T6. The most common trigger is a noxious stimulus below the level of injury, typically a distended bladder or bowel impaction.

Question 313

Topic: 1. General Principles & Basic Science
An elderly patient with pre-existing cervical spondylosis presents after a hyperextension injury to the neck. Examination shows bilateral motor weakness that is much more pronounced in the upper extremities than the lower extremities. What is the most likely diagnosis?
. Anterior cord syndrome
. Central cord syndrome
. Brown-Sรฉquard syndrome
. Posterior cord syndrome

Correct Answer & Explanation

. Central cord syndrome

Explanation

Central cord syndrome is classically caused by hyperextension injuries in patients with pre-existing cervical spondylosis. It causes motor weakness that affects the upper extremities more severely than the lower extremities due to the central location of the cervical motor tracts.

Question 314

Topic: 1. General Principles & Basic Science

A patient with a herniated disk has a diminished patellar tendon reflex. Which of the following lumbosacral nerve roots is affected:

. L1
. L2
. L3
. L4
. L5

Correct Answer & Explanation

. L4

Explanation

The patellar tendon reflex is primarily transmitted through the L4 lumbosacral nerve root. Although the L4 lumbosacral nerve root is the primary transmitter, the L2 and L3 lumbosacral nerve roots also contribute to the fibers. A weak reflex is present if the L4 lumbosacral nerve root is completely cut and fibers of the L2 and L3 lumbosacral nerve roots are still present. The patellar tendon reflex is seldom completely absent unless a patient has primary muscle or anterior horn lesions.

Question 315

Topic: 1. General Principles & Basic Science

If the extensor hallucis longus muscle is weak in a patient who has radicular pain, then which of the following lumbosacral nerve roots is compressed:

. L1
. L2
. L3
. L4
. L5

Correct Answer & Explanation

. L5

Explanation

The extensor hallucis longus muscle is primarily innervated by the L5 lumbosacral nerve root. The L5 lumbosacral nerve root innervates the following muscles: Extensor hallucis longus Extensor digitorum longus and extensor digitorum brevis Gluteus medius

Question 316

Topic: 1. General Principles & Basic Science

If the extensor digitorum longus and extensor digitorum brevis muscles are weak in a patient who has radicular back pain, then which of the following lumbosacral nerve roots is compressed:

. L1
. L2
. L3
. L4
. L5

Correct Answer & Explanation

. L5

Explanation

The extensor hallucis longus muscle is primarily innervated by the L5 lumbosacral nerve root. The L5 lumbosacral nerve root innervates the following muscles: Extensor hallucis longus Extensor digitorum longus and extensor digitorum brevis Gluteus medius

Question 317

Topic: 1. General Principles & Basic Science

If the peroneus longus and peroneus brevis muscles are weak in a patient who has radicular back pain, then which of the following nerve roots is compressed:

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. S1

Explanation

The peroneus brevis and peroneus longus muscles are principally innervated by the S1 nerve root through the superficial peroneal nerve. Although the nerve is principally innervated by the S1 nerve root, the superficial peroneal nerve is derived from the L5, S1, and S2 nerve roots. The muscles principally innervated by the S1 nerve root are the: Peroneus longus and peroneus brevis Gastrocnemius-soleus complex Gluteus maximus

Question 318

Topic: Surgical Anatomy & Approaches

A patient presents with isolated weakness of the deltoid and biceps after a high-energy motor vehicle accident. Which cervical nerve root is most likely compromised?

. C4
. C5
. C6
. C7
. C8

Correct Answer & Explanation

. C5

Explanation

The C5 nerve root primarily innervates the deltoid (via the axillary nerve) and biceps (via the musculocutaneous nerve). Deficits result in profound weakness in shoulder abduction and elbow flexion.

Question 319

Topic: Physiology & Rehabilitation

A patient sustains a stab wound to the right side of the neck at the C6 level. Which of the following neurological patterns is expected?

. Right-sided loss of pain and temperature, left-sided loss of motor function
. Bilateral loss of pain and temperature, preserved motor function
. Right-sided loss of motor function and proprioception, left-sided loss of pain and temperature
. Left-sided loss of motor function and proprioception, right-sided loss of pain and temperature
. Bilateral loss of motor function with preserved proprioception

Correct Answer & Explanation

. Right-sided loss of motor function and proprioception, left-sided loss of pain and temperature

Explanation

Brown-Sequard syndrome (hemisection of the cord) causes ipsilateral loss of motor function and proprioception (corticospinal and dorsal columns) and contralateral loss of pain and temperature sensation (spinothalamic tract).

Question 320

Topic: Physiology & Rehabilitation

A patient suffers an ischemic injury to the anterior spinal artery. Which of the following neurologic functions will remain intact?

. Motor function
. Pain sensation
. Temperature sensation
. Proprioception and vibratory sense
. Bowel and bladder control

Correct Answer & Explanation

. Proprioception and vibratory sense

Explanation

Anterior cord syndrome spares the dorsal columns, which are supplied independently by the posterior spinal arteries. Therefore, proprioception, vibratory sense, and fine touch remain intact while motor, pain, and temperature functions are lost.

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