Question 1

Which of the following populations is most at risk for compression fractures of the spine:

Explanation

Osteoporosis is an age-related decrease in bone mass usually associated with a loss of estrogen in postmenopausal women. Sedentary, thin white women of northern European descent are most severely affected. In addition, smoking, heavy drinking, and certain pharmacological agents, such as phenytoin, increase the severity of the disease. Women who breastfed their infants or those with low vitamin D or calcium diets are also at increased risk.

Question 2

Following an osteoporotic compression fracture, the risk of sustaining another compression fracture at a different level is increased by:

Explanation

Osteoporosis is a systemic disease affecting more than 24 million Americans. Osteoporosis results in progressive bone mineral loss and concurrent changes in bony architecture, which leave the spinal column vulnerable to compression fractures, often after minimal or no trauma. There are an estimated 700,000 osteoporotic vertebral compression fractures (VC Fs) in the United States each year, of which more than one third become chronically painful. Approximately 85% of VC Fs are due to primary osteoporosis and the remainder due to secondary osteoporosis or malignancies. These VC Fs lead to progressive sagittal spine deformity and changes in spinal biomechanics and are believed to contribute to a fivefold increased risk of further fracture by virtue of force transmission to weak vertebrae above or below. Whether the fracture is painful or not, the spinal deformity caused by two or more fractures dramatically impacts health, daily living, and medical costs through loss of lung capacity, loss of appetite, reduced mobility, chronic pain, and/or clinical depression.

Question 3

The following are all purported benefits of percutaneous intraosseous methylmethacrylate injection (vertebroplasty) for the treatment of osteoporotic compression fractures except:

Explanation

Traditional treatment for patients with osteoporotic vertebral compression fractures (VC Fs) includes bed rest, analgesics, and bracing. This type of medical management does not restore spinal alignment, and the lack of mobility increases the rate of demineralization. Because of the inherent risks and invasive nature, surgical treatment of osteoporotic VCFs has been limited to patients with concurrent spinal instability or neurologic compromise. Reconstruction with structural bone graft and instrumentation may be performed from an anterior or posterior approach; however, the success of these techniques is limited by a patients poor bone quality and general medical condition. Augmentation of VC Fs with polymethylmethacrylate (PMMA), "vertebroplasty," involves the forced injection of low viscosity PMMA cement into the closed space of the collapsed vertebral body. Although vertebroplasty is currently being used successfully for pain relief in VC Fs, this technique does not restore the height of the collapsed vertebral body.

Question 4

Acute thoracic compression fractures should have the following signal characteristics on magnetic resonance imaging:

Explanation

Acute fractures produce local hematomas that displace the adipose tissue normally present in the bone marrow and decrease the signal uptake from fat on T1-weighted sequences. Fractures also produce edema, which is bright on T2-weighted sequences. Acute thoracic compression fractures should be low signal intensity on T1 sequences and high on T2 sequences.

Question 5

In this slide of a lumbar burst fracture, which column is disrupted to distinguish it from a compression fracture:

Explanation

Denis was the first surgeon to include the middle column in his description of thoracolumbar fractures and to accentuate its importance in fracture stability. The defining characteristic of a burst fracture is disruption of the middle column, which distinguishes these fractures from compression fractures. Involvement of the middle column indicates an unstable fracture pattern.

Question 6

When evaluating thoracolumbar burst fractures, it is important to remember that the spinal cord ends in the conus medullaris, which typically is present at what level:

Explanation

While the conus medullaris can end anywhere from T12 to L3, in the majority of patients it is present at the L1 level. Injury at this level is much different from injury to the spinal cord or the cauda equina.

Question 7

Canal compromise in burst fractures (Slide) is caused by:

Explanation

An essential component of burst fractures, as described first by Denis, is the involvement of the middle column. Typically, the posterosuperior vertebral body is separated from the remainder of the body and encroaches into the spinal canal, causing damage to the neural elements. No other part of the middle column is a standard component of the injury.

Question 8

A 16-year-old boy sustains a burst fracture of L2. Radiographs indicate loss of approximately 20% of vertebral height anteriorly and 10° of kyphosis. He is neurologically intact. Management should include:

Orthopedic Prometric Exam Chapter 3 Image

Explanation

Burst fractures represent 17% of major spine fractures. Instability and failure occur in the anterior and middle columns. Fifty percent of patients have a neurologic deficit. These fractures are considered unstable if there is more than 50% to 60% anterior compression, 20° to 25° of kyphosis, more than 50% of canal compromise, and posterior injury. Incomplete or progressive neurologic deficits require early decompression and stabilization. Treatment of the stable fracture without neurologic deficit is hyperextension bracing for 3 to 4 months.

Question 9

The sagittal plumb line should fall:

Explanation

Radiographic assessment of the sagittal balance is usually made with a patient standing, with his or her arms flexed forward 90° and supported on a bar. Radiographic assessment is recorded on a 36-inch cassette. Several reference points regarding this technique have appeared in the literature. These points include a plumb line through the center of the C 7 vertebral body, passing 35 mm to 56 mm posterior to the anterosuperior border of S1.

Question 10

Normal sagittal thoracic alignment is:

Explanation

Thoracic kyphosis has contributions from the trapezoidal shapes of the thoracic vertebrae, from the intevertebral disk positions, and from the stiffness of the ribs and sternum. The reported normal values range from 20° to 50°.

Question 11

A 70-year-old man complains of severe, burning pain in both calves after he ambulates approximately one block. He denies significant back pain. He has long-standing, insulin-dependent diabetes mellitus and a history of coronary artery disease. The patient has smoked two packs of cigarettes each day for more than 30 years. What questions from his history can help differentiate vascular from neurogenic claudication:

Explanation

Pain distribution may be similar in vascular and neurogenic claudication. The pattern of patient-reported sensory loss is unlikely to be contributory due to the patientâ s history of insulin-dependent diabetes and, presumably, a diabetic peripheral neuropathy. In both syndromes, pain is relieved with rest. Usually, pain relief is quicker in vascular claudication. In neurogenic claudication, standing alone may not relieve patient symptoms; sitting is usually required. Timing of symptom onset is variable in both syndromes. Vascular claudication usually produces less variability in exercise tolerance. Relief of pain with changes in posture (bending over a walker or shopping cart) is found only in neurogenic claudication.

Question 12

A 70-year-old man complains of severe, burning pain in both calves after he ambulates approximately one block. He denies significant back pain. He has long-standing, insulin-dependent diabetes mellitus and a history of coronary artery disease. The patient has smoked two packs of cigarettes each day for more than 30 years. The patient is diagnosed with neurogenic claudication. What is the most likely source of his symptoms:

Explanation

The most common cause of neurogenic claudication in this patient is degenerative stenosis. L4-L5 is the most commonly affected level. Herniated lumbar disk is less likely. Although a metastatic tumor is possible, especially in light of the patientâ s smoking history, the absence of back pain makes this unlikely.

Question 13

A 70-year-old man complains of severe, burning pain in both calves after he ambulates approximately one block. He denies significant back pain. He has long-standing, insulin-dependent diabetes mellitus and a history of coronary artery disease. The patient has smoked two packs of cigarettes each day for more than 30 years. A magnetic resonance image (MRI) of the patient is obtained (Slide). What does the MRI show:

Explanation

Orthopedic Prometric Exam Chapter 3 Image

The MRI shows moderately severe lumbar stenosis at L3-L4 and L4-L5. While the degree or severity of stenosis remains subjective, terming this stenosis critical is an exaggeration. The section of the axial images at L5-S1 is not in plane with the disk, hence there appears to be lateral recess stenosis at this level also. The sagittal images, however, do not confirm this diagnosis. There is no evident lumbar disk herniation, and there are no findings indicative of lumbar metastatic disease.

Question 14

A 70-year-old man complains of severe, burning pain in both calves after he ambulates approximately one block. He denies significant back pain. He has long-standing, insulin-dependent diabetes mellitus and a history of coronary artery disease. The patient has smoked two packs of cigarettes each day for more than 30 years. A magnetic resonance image (MRI) of the patient is obtained, as well as a myelogram (Slide). Conservative options in this patient include:

Orthopedic Prometric Exam Chapter 3 Image

Explanation

The myelogram confirms the diagnosis of lumbar spinal stenosis at L3-L4 and L4-L5. There is no myelographic block, although the stenosis is significant. A trial of conservative therapy is appropriate for this patient.

Question 15

A 70-year-old man complains of severe, burning pain in both calves after he ambulates approximately one block. He denies significant back pain. He has long-standing, insulin-dependent diabetes mellitus and a history of coronary artery disease. The patient has smoked two packs of cigarettes each day for more than 30 years. Based upon the patientâ s history, magnetic resonance image (MRI) (Slide 1), and computed tomography (CT)-myelogram (Slide 2) available for your review, what is the correct diagnosis in this patient:

Explanation

There is no evidence of lumbar metastases in this patient. The C T- myelogram shows compression arising posterior to the thecal sac, making a disk herniation less likely. Similarly, there is no evidence of a lumbar disk herniation on MRI. The patientâ s sagittal alignment is well maintained, with no spondylolisthesis evident. Ankylosing spondylitis generally presents in younger patients, and the classic radiographic finding of spontaneous arthrodesis is not present.

Question 16

A 75-year-old woman presents with low back pain that is worse with motion and bilateral lower extremity pain that is worse with ambulation. She notes that the pain extends down the posterior aspects of her lower extremities, from the buttocks to the calves. The pain limits her activity â she can only ambulate approximately one block before having to rest. She reports that lumbar flexion, notably leaning over a walker or a shopping cart, considerably diminishes her lower extremity pain. She has a significant past medical history of coronary artery disease, and she has had previous angioplasty of her coronary vessels. On examination, her lower extremity pulses are easily palpable. What would you expect to find on this patientâ s neurological examination:

Explanation

Lumbar spinal stenosis is a dynamic process. Patients classically have no deficit until they are physically active. Therefore, this patient may not have a deficit during her clinic examination. It would be unusual for her to present with a fixed lower extremity deficit.

Question 17

A 75-year-old woman presents with low back pain that is worse with motion and bilateral lower extremity pain that is worse with ambulation. She notes that the pain extends down the posterior aspects of her lower extremities, from the buttocks to the calves. The pain limits her activity â she can only ambulate approximately one block before having to rest. She reports that lumbar flexion, notably leaning over a walker or a shopping cart, considerably diminishes her lower extremity pain. She has a significant past medical history of coronary artery disease, and she has had previous angioplasty of her coronary vessels. On examination, her lower extremity pulses are easily palpable. What radiographic evaluation would you obtain to best establish her diagnosis:

Explanation

The most efficacious and least invasive means of evaluation for lumbar spinal stenosis is MRI. A CT scan, while showing bony anatomy well, may not provide adequate information about soft tissue structures. Plain films are nonspecific and, although they are often used as an initial evaluation, may not yield adequate diagnosis. This patientâ s symptom complex does not correlate with vascular claudication.

Question 18

A 75-year-old woman presents with low back pain that is worse with motion and bilateral lower extremity pain that is worse with ambulation. She notes that the pain extends down the posterior aspects of her lower extremities, from the buttocks to the calves. The pain limits her activity â she can only ambulate approximately one block before having to rest. She reports that lumbar flexion, notably leaning over a walker or a shopping cart, considerably diminishes her lower extremity pain. She has a significant past medical history of coronary artery disease, and she has had previous angioplasty of her coronary vessels. On examination, her lower extremity pulses are easily palpable. This patient is diagnosed with degenerative spondylolisthesis with significant lateral recess stenosis. Treatment of this patient could include:

Explanation

Treatment options for this patient are legion. Considering her significant coronary artery disease, a conservative approach using anti-inflammatory drugs, physical therapy, and epidural steroids might be chosen by some physicians. Surgical options include decompression alone or decompression with fusion. This patientâ s significant mechanical low back pain encourages some surgeons to include a fusion with the decompression.

Question 19

The distinguishing phenotypic feature that differentiates a schwannoma from a neurofibroma is:

Explanation

Nerve sheath tumors account for 25% of intradural spinal cord tumors in adults and can be further broken down into either schwannomas or neurofibromas. Schwannomas are more common than neurofibromas, most commonly occurring in patients 30 to 50 years of age, equally between the sexes. Most schwannomas arise in the dorsal nerve root. Neurofibromas, however, have a predilection to the ventral root. Both tumors primarily are intradural but as many as 10% to 15% can escape through the dura to form a dumbbell shape and exist as both an intradural and extradural tumor. Histologically, fibrous tissue and nerve fibers make up a neurofibroma. Grossly, neurofibromas appear as a fusiform enlargement of the nerve, making a clear distinction between tumor and nerve impossible. Macroscopically, schwannomas look like smooth globoid masses sitting on the nerve fiber and a clear resection plane is apparent.

Question 20

What is the advantage of performing a magnetic resonance image (MRI) to evaluate spinal tumors:

Explanation

Although diagnosis and localization of spinal column tumors depends on a patientâ s history and physical examination, differentiation of intramedullary versus extramedullary location of a tumor relies primarily on image findings. The most common imaging modality is MRI. Lesion signal abnormalities, cerebral spinal fluid (CSF) capping, and cord or cauda equina displacement signify extramedullary masses, even without contrast. Gadolinium enhancement increases the sensitivity of the MRI, as almost all spinal cord tumors demonstrate some contrast enhancement. Although more sensitive than MRI, myelography and postmyelography CT are rarely used initially due to their invasive nature.

Question 21

Which of the following represents an absolute contraindication to performing a percutaneous vertebroplasty for a painful osteoporotic compression fracture?

Explanation

Active infection such as osteomyelitis, discitis, or systemic bacteremia is an absolute contraindication to percutaneous cement augmentation due to the high risk of abscess formation and failure of eradication.

Question 22

When evaluating an elderly patient with a suspected acute osteoporotic vertebral compression fracture, which MRI sequence is most reliable for differentiating an acute fracture from a chronic, healed deformity?

Explanation

STIR or fat-suppressed T2 sequences are highly sensitive for detecting bone marrow edema. The presence of marrow edema reliably distinguishes an acute or healing fracture from a chronic, healed fracture.

Question 23

Compared to vertebroplasty, balloon kyphoplasty generally offers which of the following biomechanical or procedural advantages?

Explanation

Balloon kyphoplasty creates a low-pressure cavity within the vertebral body, allowing for the injection of higher viscosity cement. This technique significantly lowers the risk of cement extravasation compared to the high-pressure injection used in vertebroplasty.

Question 24

What is the most common serious systemic complication associated with the injection of polymethylmethacrylate (PMMA) during vertebroplasty?

Explanation

Pulmonary cement embolism occurs when PMMA leaks into the paravertebral venous plexus and migrates to the lungs. While often asymptomatic, it can cause acute respiratory distress and requires careful fluoroscopic monitoring during cement injection.

Question 25

Which anatomic region of the spine is the most common site for osteoporotic vertebral compression fractures?

Explanation

The thoracolumbar junction (T11-L1) is the most frequent site of osteoporotic compression fractures. This is due to the biomechanical stress concentration at the transition zone between the rigid, kyphotic thoracic spine and the mobile, lordotic lumbar spine.

Question 26

Kummell disease is a recognized complication following a vertebral compression fracture. Which of the following best describes its classic radiographic presentation?

Explanation

Kummell disease represents a delayed post-traumatic vertebral collapse resulting from avascular necrosis of the vertebral body. It characteristically presents with an intravertebral vacuum cleft on extension or traction radiographs.

Question 27

In an elderly patient with severe osteoporosis requiring posterior spinal instrumentation for instability, which technique is most effective for maximizing pedicle screw pullout strength?

Explanation

PMMA augmentation of fenestrated pedicle screws significantly increases the screw-bone interface strength. This is the most effective biomechanical method to prevent screw pullout in severely osteoporotic bone.

Question 28

A 75-year-old female presents with multiple severe thoracic osteoporotic compression fractures. Which of the following physiologic consequences is most likely to be found on her clinical evaluation?

Explanation

Severe progressive thoracic kyphosis from multiple compression fractures reduces the volume of the thoracic cavity. This characteristically leads to restrictive lung disease, demonstrating decreased forced vital capacity on pulmonary function testing.

Question 29

A 72-year-old female presents with severe back pain 2 weeks after a minor fall. Radiographs show a T12 compression fracture with 20% anterior height loss. MRI confirms acute edema without spinal canal compromise. Neurological exam is intact. What is the most appropriate initial management?

Explanation

The gold standard initial management for a stable osteoporotic compression fracture without neurologic deficit is conservative care. This includes pain control, early mobilization, and an orthosis, with surgical options reserved for refractory cases.

Question 30

Teriparatide therapy reduces the risk of future vertebral compression fractures primarily through which mechanism of action?

Explanation

Teriparatide is a recombinant parathyroid hormone (PTH 1-34) that acts as a potent anabolic agent when given intermittently. It directly stimulates osteoblast activity, leading to new bone formation and improved trabecular microarchitecture.

Question 31

A 45-year-old male presents with a spontaneous L1 compression fracture. He has no history of trauma, long-term steroid use, or known systemic medical conditions. What is the most critical next step in his medical workup?

Explanation

A spontaneous vertebral compression fracture in a young or middle-aged male is highly suspicious for a secondary cause, particularly multiple myeloma. SPEP and UPEP are essential initial screening tools in this demographic.

Question 32

Following an initial osteoporotic vertebral compression fracture, the risk of sustaining a subsequent vertebral fracture at an adjacent level is highest during which time frame?

Explanation

The risk of sustaining a subsequent vertebral compression fracture is greatest within the first year after the initial fracture. This acute risk elevation is driven by both the underlying severe osteoporosis and the immediate biomechanical changes at the adjacent segments.

Question 33

Which of the following conditions represents an absolute medical contraindication to initiating oral bisphosphonate therapy in a patient with an osteoporotic compression fracture?

Explanation

Bisphosphonates are excreted unchanged via the kidneys and can accumulate, causing toxicity. They are absolutely contraindicated in patients with severe renal impairment, typically defined as a creatinine clearance of less than 30 to 35 mL/min.

Question 34

A major biomechanical consequence of an uncorrected wedge compression fracture in the mid-thoracic spine is:

Explanation

A wedge compression fracture increases the local thoracic kyphosis, which shifts the body's center of gravity anteriorly. This creates a longer lever arm and an increased anterior bending moment, placing greater compressive stress on adjacent vertebral bodies.

Question 35

The rapid and significant pain relief observed following a successful vertebroplasty is primarily attributed to mechanical stabilization of the microfractures and:

Explanation

Pain relief in vertebroplasty is widely believed to result from the immediate mechanical stabilization of trabecular microfractures. Additionally, the exothermic polymerization of the PMMA cement causes thermal necrosis of intraosseous nerve endings, contributing to analgesia.

Question 36

An 80-year-old female with known osteoporosis presents with severe back pain and an acute L2 compression fracture. Under what specific circumstance would open operative decompression and stabilization be indicated over percutaneous cement augmentation?

Explanation

A progressive neurologic deficit caused by canal compromise from retropulsed bone fragments is a clear indication for surgical decompression. Cement augmentation alone cannot decompress the neural elements and carries a risk of exacerbating the stenosis.

Question 37

According to the World Health Organization (WHO) criteria, severe (or established) osteoporosis is defined by a fragility fracture and a Dual-energy X-ray absorptiometry (DEXA) T-score of:

Explanation

The WHO defines osteoporosis as a DEXA T-score of -2.5 or lower. The designation of "severe" or "established" osteoporosis is applied when a patient has a T-score of ≤ -2.5 combined with one or more fragility fractures.

Question 38

Denosumab is highly effective for patients with severe osteoporosis and recurrent vertebral fractures. What is its precise mechanism of action?

Explanation

Denosumab is a fully human monoclonal antibody that specifically binds to and inhibits RANK Ligand (RANKL). This prevents RANKL from activating the RANK receptor on osteoclast precursors, thereby profoundly inhibiting osteoclast formation, function, and survival.

Question 39

In a patient with a neurologically intact, acutely painful osteoporotic compression fracture, what is the generally recommended minimum duration for a trial of optimal conservative management before considering vertebroplasty?

Explanation

Most clinical guidelines recommend a trial of optimal medical management, including analgesics and orthotics, for at least 4 to 6 weeks before offering percutaneous cement augmentation. Many patients will experience significant natural improvement in pain during this timeframe.

Question 40

During a percutaneous vertebroplasty, extravasation of PMMA cement into the neural foramen most commonly manifests clinically as:

Explanation

Cement leakage into the neural foramen directly impinges upon the exiting nerve root. This typically presents as an acute radiculopathy, characterized by radiating pain, numbness, or focal weakness in the specific distribution of the affected nerve.

Question 41

Compared to percutaneous vertebroplasty, balloon kyphoplasty has been shown to have which of the following characteristics when used for the treatment of osteoporotic vertebral compression fractures?

Explanation

Balloon kyphoplasty creates a cavity with an inflatable tamp before low-pressure cement injection, resulting in significantly lower rates of cement extravasation compared to high-pressure vertebroplasty.

Question 42

A 75-year-old female presents with severe, unremitting back pain after a fall from standing height. MRI shows an acute L1 compression fracture. She has failed 6 weeks of conservative management. What is an absolute contraindication to performing a vertebroplasty?

Explanation

Active infection (osteomyelitis or discitis) and uncorrectable coagulopathy are absolute contraindications to vertebroplasty and kyphoplasty. Asymptomatic retropulsion and posterior wall involvement are relative contraindications.

Question 43

A 72-year-old female sustains a T12 osteoporotic compression fracture. Which of the following MRI sequences is most sensitive for determining whether the fracture is acute or chronic?

Explanation

STIR (Short tau inversion recovery) or T2 fat-suppressed MRI sequences are the most sensitive for detecting bone marrow edema. This edema differentiates an acute or subacute compression fracture from a chronic, healed fracture.

Question 44

An 80-year-old male presents with acute back pain. Imaging shows a pathological vertebral compression fracture.

Which of the following MRI findings is most indicative of a malignant compression fracture rather than a benign osteoporotic fracture?

Explanation

Malignant compression fractures typically demonstrate pedicle or posterior element involvement, a convex (bulging) posterior vertebral body margin, and complete marrow replacement. Benign fractures typically spare the pedicles.

Question 45

Which medication provides the most rapid, specific analgesic effect for acute osteoporotic vertebral compression fractures within the first few weeks of injury?

Explanation

Intranasal calcitonin has been shown to provide a significant, early analgesic effect in acute osteoporotic vertebral compression fractures. It is often prescribed early in the fracture course specifically for this symptom-modifying property.

Question 46

A 68-year-old woman with a T-score of -3.0 sustains a T11 compression fracture. She is started on a daily subcutaneous medication that acts as an anabolic agent to stimulate bone formation. What is the mechanism of action of this medication?

Explanation

Teriparatide is a recombinant human PTH analog administered daily subcutaneously. It acts as an anabolic agent by stimulating osteoblast activity and directly forming new bone.

Question 47

Following a successful percutaneous vertebroplasty for a painful L1 osteoporotic compression fracture, the patient is at increased risk for developing which of the following complications in the surrounding anatomy?

Explanation

After vertebroplasty, the increased stiffness of the augmented vertebral body alters load transmission. This mechanical mismatch significantly increases the risk of subsequent fractures in the adjacent vertebral bodies.

Question 48

A 65-year-old female with osteoporosis is being treated conservatively for a T12 compression fracture. What is the expected role of orthotic bracing (e.g., TLSO or Jewett brace) in this patient?

Explanation

Current literature indicates that orthotic bracing for osteoporotic compression fractures aids in early pain control and allows for earlier mobilization. However, it does not significantly prevent long-term progressive kyphosis or accelerate fracture union.

Question 49

In the Denis three-column classification of spinal injuries, a simple osteoporotic compression fracture is typically characterized by failure of which of the following?

Explanation

A simple wedge compression fracture involves failure of only the anterior column under compressive forces. The middle and posterior columns remain completely intact.

Question 50

What is the most common anatomical location for osteoporotic vertebral compression fractures?

Explanation

The thoracolumbar junction (T11-L2) is the most common site for osteoporotic compression fractures. This is due to the abrupt biomechanical transition from the rigid, kyphotic thoracic spine to the mobile, lordotic lumbar spine.

Question 51

During a kyphoplasty for an L2 compression fracture, the surgeon notices a sudden drop in the patient's blood pressure, tachycardia, and a decrease in oxygen saturation immediately after cement injection. What is the most likely cause?

Explanation

PMMA cement pulmonary embolism is a recognized, potentially life-threatening complication of vertebroplasty/kyphoplasty. It is caused by cement extravasation into the paravertebral venous plexus, tracking into the inferior vena cava and pulmonary arteries.

Question 52

A 78-year-old patient with severe osteoporosis presents with multiple wedge compression fractures.

According to the World Health Organization (WHO) definition, severe osteoporosis is diagnosed when a patient has a fragility fracture and a DEXA T-score of:

Explanation

The WHO defines osteoporosis as a DEXA T-score of -2.5 or lower. Severe (or established) osteoporosis is defined as a T-score of -2.5 or lower in the presence of one or more fragility fractures.

Question 53

Which of the following factors most strongly indicates the need for formal surgical decompression and stabilization rather than percutaneous vertebroplasty for an acute osteoporotic vertebral fracture?

Explanation

Vertebroplasty and kyphoplasty stabilize the fracture but do not decompress the neural elements. The presence of a progressive neurological deficit is an absolute indication for formal surgical decompression (e.g., laminectomy/corpectomy) and stabilization.

Question 54

A 55-year-old male sustains an L1 fracture after a fall.

Which plain radiographic finding best differentiates a burst fracture from a simple compression fracture?

Explanation

Widening of the interpedicular distance on the anteroposterior (AP) radiograph indicates involvement and failure of the middle column. This is the radiographic hallmark that differentiates a burst fracture from a simple anterior column compression fracture.

Question 55

Kümmell disease is an eponym historically used to describe which of the following conditions following a spinal fracture?

Explanation

Kümmell disease refers to delayed, progressive post-traumatic vertebral collapse secondary to avascular necrosis of the vertebral body. It frequently presents with an intravertebral vacuum cleft on imaging.

Question 56

When evaluating a patient's risk for future osteoporotic fractures using the FRAX tool, which of the following is NOT included as a primary variable in the calculation?

Explanation

The FRAX (Fracture Risk Assessment Tool) algorithm evaluates 11 clinical risk factors including age, sex, BMI, prior fracture, parental hip fracture, current smoking, glucocorticoid use, rheumatoid arthritis, secondary osteoporosis, alcohol intake, and femoral neck BMD. Serum Vitamin D levels are not a variable.

Question 57

Romosozumab is a newer pharmacological agent used in patients with severe osteoporosis and multiple compression fractures. Its primary mechanism of action is:

Explanation

Romosozumab is a humanized monoclonal antibody that binds to and inhibits sclerostin. This has a dual effect: increasing bone formation (anabolic) and decreasing bone resorption (anticatabolic).

Question 58

The "intravertebral vacuum cleft sign" seen on radiographs or CT of a vertebral body compression fracture is highly indicative of:

Explanation

The intravertebral vacuum cleft sign represents gas (mostly nitrogen) filling a non-healing void, indicative of avascular necrosis (osteonecrosis) within the vertebral body. It is strongly associated with delayed vertebral collapse (Kümmell disease) and pseudarthrosis.

Question 59

A 70-year-old male with long-standing ankylosing spondylitis presents with back pain after a minor ground-level fall. Initial plain radiographs of the spine are reported as "unremarkable." What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis have highly rigid, osteoporotic spines. Any minor trauma can cause highly unstable, often occult fractures. Advanced cross-sectional imaging (CT or MRI) of the entire spine is mandatory even if plain films are normal.

Question 60

For a patient undergoing kyphoplasty for an osteoporotic compression fracture, the polymethylmethacrylate (PMMA) cement should ideally be injected at which of the following consistencies to minimize the risk of venous extravasation?

Explanation

PMMA cement should be injected during the doughy (or toothpaste-like) phase. Injecting while it is too liquid significantly increases the risk of extravasation into the venous plexus, potentially leading to a pulmonary embolism.

Question 61

A 75-year-old female presents with severe back pain after a fall. Plain radiographs show compression fractures at T11 and L1. Which MRI sequence is most specific for determining which fracture is acute?

Explanation

STIR sequences suppress fat and highlight fluid and edema, making them ideal for identifying acute fractures. A hyperintense signal on STIR indicates marrow edema, reliably distinguishing an acute or subacute fracture from a healed chronic compression fracture.

Question 62

A 68-year-old female presents with progressively worsening back pain 3 months after a minor fall. Radiographs show a T12 compression fracture with an intravertebral vacuum cleft that enlarges on an extension view. What is the most likely diagnosis?

Explanation

Kummell disease is delayed post-traumatic avascular necrosis of a vertebral body following an ischemic insult. It is classically associated with an intravertebral vacuum cleft that dynamically changes in size with flexion and extension.

Question 63

Compared to percutaneous vertebroplasty, balloon kyphoplasty has been shown to have a lower rate of which of the following complications?

Explanation

Balloon kyphoplasty creates a low-pressure cavity within the cancellous bone before cement injection. This significantly reduces the risk of cement extravasation compared to the high-pressure injection technique required in vertebroplasty.

Question 64

Which of the following is considered an absolute contraindication to performing a percutaneous vertebroplasty?

Explanation

Active systemic infection or localized spinal infection (such as osteomyelitis or discitis) is an absolute contraindication to PMMA injection. Injecting cement into an infected area can trap the infection and worsen the patient's condition.

Question 65

A 72-year-old female sustains an osteoporotic L1 compression fracture. She is neurologically intact but has severe pain. What is the recommended minimum duration of non-operative management prior to considering vertebral augmentation?

Explanation

Most osteoporotic compression fractures heal and become asymptomatic with conservative care. Vertebral augmentation is typically reserved for patients who have persistent, severe pain after failing 4 to 6 weeks of conservative management including bracing and analgesia.

Question 66

A 74-year-old female undergoes percutaneous vertebroplasty for a T12 compression fracture. Two hours postoperatively, she develops acute dyspnea, tachycardia, and pleuritic chest pain. What is the most likely etiology?

Explanation

Polymethylmethacrylate (PMMA) can extravasate into the paravertebral venous plexus and embolize to the lungs. Symptomatic cement pulmonary embolisms present with sudden acute dyspnea and chest pain shortly after the procedure.

Question 67

During the evaluation of a thoracic compression fracture, distinguishing between an osteoporotic etiology and a neoplastic process is critical. Which of the following radiographic findings is highly suspicious for a neoplastic etiology?

Explanation

Osteoporotic compression fractures typically spare the posterior elements, including the pedicles. Pedicle destruction, visible as the 'winking owl' sign on an AP radiograph, strongly suggests a metastatic or primary neoplastic process.

Question 68

A 70-year-old female undergoes the procedure shown for a painful osteoporotic compression fracture. What is the primary theoretical mechanical advantage of this specific technique over standard cement injection?

Explanation

The image demonstrates balloon kyphoplasty, which utilizes an inflatable bone tamp. The primary theoretical advantage is the partial restoration of vertebral body height and correction of kyphotic deformity prior to low-pressure cement injection.

Question 69

A 65-year-old female with an acute L2 osteoporotic compression fracture is prescribed an orthosis. Which type of orthosis is biomechanically most appropriate for treating this injury?

Explanation

Osteoporotic compression fractures typically involve anterior column collapse. A hyperextension brace, such as a Jewett or cruciform anterior spinal hyperextension (CASH) brace, unloads the anterior vertebral body by shifting the axial load to the intact posterior elements.

Question 70

A patient with multiple osteoporotic compression fractures is evaluated for teriparatide therapy. This medication is strictly contraindicated in patients with a history of which of the following conditions?

Explanation

Teriparatide is a recombinant parathyroid hormone analogue with an anabolic effect on bone. It carries a black box warning for osteosarcoma and is contraindicated in patients with Paget disease, prior skeletal radiation, or unexplained elevations of alkaline phosphatase.

Question 71

An elderly patient presents with severe back pain and the characteristic radiographic finding shown. Advanced imaging confirms a fluid-filled cleft within the vertebral body. Which of the following best explains the pathogenesis of this specific finding?

Explanation

The presence of an intravertebral vacuum cleft characterizes Kummell disease. This represents delayed avascular necrosis of the vertebral body, resulting from an ischemic insult following a prior compression fracture.

Question 72

During a percutaneous vertebroplasty, what volume of PMMA injection is generally sufficient to achieve significant pain relief and stabilization in a typical thoracolumbar vertebral body?

Explanation

Clinical studies show that pain relief and mechanical stabilization do not require complete filling of the vertebral body. Filling approximately 15% of the vertebral volume, typically 2 to 4 cc in the thoracolumbar spine, is generally sufficient and minimizes leakage risk.

Question 73

A 71-year-old female presents with bilateral lower extremity weakness and hyperreflexia following a fall. Imaging shows a T8 osteoporotic compression fracture with retropulsion of bone causing severe spinal cord compression. What is the most appropriate management?

Explanation

Neurological deficit secondary to spinal cord compression from a retropulsed bone fragment is an absolute contraindication to vertebroplasty or kyphoplasty alone. Such cases require open surgical decompression and formal stabilization to relieve the myelopathy.

Question 74

A well-documented complication following vertebral augmentation procedures is adjacent segment vertebral fracture. What is the most widely accepted biomechanical mechanism contributing to this complication?

Explanation

Augmenting an osteoporotic vertebral body with PMMA significantly increases its compressive stiffness. This creates a severe mechanical mismatch, transferring abnormally high stress to the adjacent softer, osteoporotic vertebrae, thereby increasing their fracture risk.

Question 75

During the vertebroplasty procedure shown, the surgeon visualizes sudden extravasation of cement tracking into the posterior epidural space on lateral fluoroscopy. What is the immediate next best step?

Explanation

If cement extravasation into the spinal canal or the basivertebral vein is visualized fluoroscopically, the injection must be halted immediately. The cannula should be repositioned or withdrawn to prevent impending neurological compromise.

Question 76

Which medical therapy has been shown to uniquely provide acute analgesic effects for osteoporotic vertebral compression fractures, in addition to its anti-resorptive properties?

Explanation

Intranasal calcitonin is unique among pharmacological osteoporosis treatments for having a documented acute analgesic effect. This effect is believed to be mediated through the release of endogenous endorphins and is useful in the acute phase of fracture management.

Question 77

When evaluating a patient with a suspected atraumatic osteoporotic compression fracture, obtaining which of the following laboratory values is critical to rule out multiple myeloma as a secondary cause?

Explanation

Multiple myeloma frequently presents with osteolytic lesions and pathological compression fractures that mimic osteoporotic fractures. Serum protein electrophoresis (SPEP) and urine protein electrophoresis (UPEP) are essential screening tests to identify the characteristic monoclonal gammopathy.

Question 78

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

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 79

A 66-year-old female sustains a simple anterior wedge compression fracture of L1 with 20% height loss and no neurologic deficits. According to Denis' three-column spine concept, which columns are disrupted in this injury pattern?

Explanation

A simple wedge compression fracture involves failure of only the anterior column under compressive axial loading. The middle column remains intact, which prevents retropulsion of bone into the spinal canal and ensures neurological stability.

Question 80

An 80-year-old woman presents with acute back pain after lifting a box. Radiographs reveal a T12 compression fracture. What is the most appropriate initial management?

Explanation

The mainstay of initial treatment for osteoporotic compression fractures is symptomatic care, including a short period of rest, analgesia, and early mobilization to prevent further bone loss and deconditioning. Surgical intervention is reserved for refractory pain or progressive deformity.

Question 81

What is an absolute contraindication to performing a percutaneous vertebroplasty for an osteoporotic compression fracture?

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 82

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?

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 83

Which MRI sequence is most useful to differentiate an acute osteoporotic compression fracture from a chronic, healed compression fracture?

Explanation

STIR sequences are highly sensitive for detecting bone marrow edema. The presence of hyperintensity on STIR confirms an acute or subacute fracture, whereas a healed, chronic fracture will show marrow signal comparable to adjacent normal vertebrae.

Question 84

A 72-year-old male with a history of prostate cancer presents with a T8 compression fracture. Which of the following MRI findings most strongly suggests a pathologic fracture rather than a benign osteoporotic fracture?

Explanation

Pathologic fractures commonly feature a convex bulging of the posterior vertebral margin, epidural mass extension, and involvement of the pedicle. Benign osteoporotic fractures typically exhibit retropulsion with a straight or concave posterior margin and band-like subchondral edema.

Question 85

Compared to percutaneous vertebroplasty, balloon kyphoplasty for the treatment of vertebral compression fractures is associated with:

Explanation

Balloon kyphoplasty creates a low-pressure cavity using an inflatable tamp, allowing for the injection of higher-viscosity cement. This significantly decreases the risk of uncontrolled cement extravasation compared to high-pressure vertebroplasty.

Question 86

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?

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 87

In a patient with an osteoporotic vertebral compression fracture, what is the clinical significance of the intravertebral vacuum cleft sign (Kümmell disease)?

Explanation

Kümmell disease is characterized by delayed post-traumatic vertebral collapse and an intravertebral vacuum cleft, representing avascular necrosis and dynamic nonunion. It often responds very well to percutaneous cement augmentation.

Question 88

Which of the following factors most significantly increases the risk of an adjacent level fracture following percutaneous vertebroplasty?

Explanation

Cement leakage into the intervertebral disc alters the normal shock-absorbing biomechanics of the spine segment. This transfers disproportionate stress to the adjacent vertebra, significantly increasing the risk of subsequent fracture.

Question 89

A 45-year-old male falls from a height and sustains an L1 burst fracture with 40% canal compromise. He is neurologically intact, and MRI confirms an intact posterior ligamentous complex (PLC). What is the most appropriate management?

Explanation

Neurologically intact patients with a stable burst fracture (intact PLC) can be successfully managed non-operatively with a TLSO and early mobilization. Laminectomy alone is contraindicated as it further destabilizes the spine.

Question 90

Look at the image provided

. In the setting of an acute traumatic spinal fracture, what is the primary purpose of meticulously assessing the posterior vertebral body wall on imaging?

Explanation

Simple compression fractures involve only the anterior column, whereas burst fractures involve the anterior and middle columns. Disruption and retropulsion of the posterior vertebral body wall are the defining hallmarks of a burst fracture.

Question 91

What is the incidence of significant neurologic deficit directly associated with a simple, benign osteoporotic wedge compression fracture?

Explanation

Simple osteoporotic wedge compression fractures rarely cause neurologic compromise because the middle and posterior columns remain intact. Any neurologic deficit should raise high clinical suspicion for a burst fracture, malignancy, or epidural mass.

Question 92

In the evaluation of a patient with long-standing ankylosing spondylitis who sustains a minor fall,

what is the classic fracture pattern expected?

Explanation

The ankylosed spine is rigid and osteoporotic, acting like a long bone. Even minor trauma can cause highly unstable, "chalk stick" fractures that extend through all three columns (transvertebral or transdiscal), carrying a high risk of neurologic injury and epidural hematoma.

Question 93

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:

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 94

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?

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 95

What is the primary mechanism of injury responsible for producing a Chance fracture of the thoracolumbar spine?

Explanation

A Chance fracture is a classic flexion-distraction injury, often occurring in motor vehicle accidents involving poorly positioned lap belts. The axis of rotation is anterior to the spine, leading to tension failure of the posterior and middle columns.

Question 96

During a balloon kyphoplasty for an L2 compression fracture

, the surgeon notes a cortical breach of the medial pedicle wall during trocar advancement. What is the most immediate critical concern?

Explanation

The medial wall of the pedicle forms the lateral boundary of the spinal canal. A medial breach during transpedicular instrumentation immediately jeopardizes the thecal sac, spinal cord, and traversing nerve roots.

Question 97

Which biomechanical change most directly accounts for the exponentially increased risk of adjacent vertebral compression fractures following severe kyphosis in the osteoporotic spine?

Explanation

Progressive kyphosis shifts the patient's center of gravity anteriorly. This increases the mechanical flexion moment arm on the anterior aspects of adjacent vertebral bodies, dramatically increasing the risk of subsequent wedge fractures.

Question 98

A 55-year-old male with known Diffuse Idiopathic Skeletal Hyperostosis (DISH) suffers a minor fall from standing and complains of new, severe back pain. Initial plain radiographs are reported as unremarkable. What is the most appropriate next step in management?

Explanation

Patients with DISH have fused, rigid spinal segments that are highly susceptible to unstable occult fractures even from low-energy trauma. If a patient with DISH presents with new pain after trauma, advanced imaging (CT/MRI) is mandatory to rule out a fracture.

Question 99

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:

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.

Orthopedic Prometric MCQs - Chapter 3 Part 1

Orthopedic Prometric MCQs - Chapter 3 Part 29

Orthopedic Prometric MCQs - Chapter 3 Part 29

Chapter Index