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6. Spine MCQs

Practice Set 374 of 379

This practice set contains high-yield board review questions covering key concepts in 6. Spine. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 7461

Topic: 6. Spine

A 68-year-old male with a 30-year history of ankylosing spondylitis presents to the emergency department after a minor ground-level fall. He complains of moderate neck pain. Neurological examination is completely normal. Lateral cervical radiographs are largely obscured by his shoulders but show a fused spine. What is the most appropriate next step in management?

. Discharge with NSAIDs and a soft cervical collar
. Perform flexion-extension cervical radiographs to assess for instability
. Obtain an immediate CT scan of the entire cervical and upper thoracic spine
. Schedule an outpatient MRI for next week to evaluate the intervertebral discs
. Admit for strict bed rest and serial neurologic exams without further imaging

Correct Answer & Explanation

. Obtain an immediate CT scan of the entire cervical and upper thoracic spine

Explanation

Patients with ankylosing spondylitis are at high risk for highly unstable "chalk stick" fractures even after minor trauma. A CT scan of the entire spine is mandatory as standard radiographs frequently miss these fractures due to altered anatomy and osteopenia.

Question 7462

Topic: 6. Spine

A patient with long-standing ankylosing spondylitis sustains a cervical spine fracture extending through the C5-C6 intervertebral disc space and posterior elements.

Several hours after admission, he develops progressive bilateral lower extremity weakness and urinary retention. What is the most critical immediate diagnostic or therapeutic step?

. Administer high-dose intravenous methylprednisolone
. Perform an immediate MRI of the cervical spine to evaluate for an epidural hematoma
. Perform an emergent closed reduction with cervical traction
. Obtain upright flexion-extension plain films
. Initiate aggressive physical therapy

Correct Answer & Explanation

. Perform an immediate MRI of the cervical spine to evaluate for an epidural hematoma

Explanation

Progressive neurological deficit in an AS patient with a spinal fracture is highly suspicious for an expanding epidural hematoma, which occurs more frequently in AS patients due to altered dural adherence and bleeding from fractured bone/vessels. Urgent MRI is required.

Question 7463

Topic: 6. Spine

Which of the following is the primary histological and pathophysiological initial event in the development of spinal ankylosis in ankylosing spondylitis?

. Chondrocyte proliferation in the nucleus pulposus
. Osteoclastic resorption of the vertebral body endplates
. Inflammation at the insertion of tendons, ligaments, and joint capsules into bone (enthesitis)
. Deposition of monosodium urate crystals in the facet joints
. Autoantibody-mediated destruction of the synovial membrane

Correct Answer & Explanation

. Inflammation at the insertion of tendons, ligaments, and joint capsules into bone (enthesitis)

Explanation

The hallmark primary lesion in ankylosing spondylitis is enthesitis (inflammation at the insertion sites of ligaments, tendons, and capsules into bone). This is eventually followed by reactive bone formation (ossification) leading to syndesmophytes and ankylosis.

Question 7464

Topic: 6. Spine

Which of the following extraskeletal manifestations is most frequently associated with the HLA-B27 positive condition ankylosing spondylitis?

. Acute anterior uveitis
. Aortic regurgitation
. Apical pulmonary fibrosis
. IgA nephropathy
. Inflammatory bowel disease

Correct Answer & Explanation

. Acute anterior uveitis

Explanation

Acute anterior uveitis (iritis) is the most common extra-articular manifestation of ankylosing spondylitis, occurring in 25-30% of patients. While cardiovascular and pulmonary complications occur, they are much less frequent.

Question 7465

Topic: 6. Spine

A 15-year-old female gymnast presents with an insidious onset of low back pain that is exacerbated by extension activities. Oblique lumbar radiographs reveal a 'Scotty dog with a collar' sign. The anatomical structure affected in this condition is located between which two regions of the vertebra?

. Superior and inferior articular processes
. Vertebral body and pedicle
. Lamina and spinous process
. Pedicle and transverse process
. Vertebral body and intervertebral disc

Correct Answer & Explanation

. Superior and inferior articular processes

Explanation

Correct Answer: Superior and inferior articular processesThe patient's presentation and radiographic findings are classic for spondylolysis, which is a stress fracture or defect of the pars interarticularis. The pars interarticularis is the segment of bone located between the superior and inferior articular processes of the facet joint. This condition is most common in adolescents who participate in sports requiring repetitive hyperextension and rotation, such as gymnastics.

Question 7466

Topic: Thoracolumbar Spine & Deformity

A 14-year-old gymnast presents with chronic low back pain exacerbated by extension. Radiographs reveal a defect in the pars interarticularis. Which of the following biomechanical forces is most directly responsible for the development of this specific lesion?

. Repetitive axial loading in a flexed posture
. Repetitive hyperextension and rotational shear stress
. Acute hyperflexion with lateral bending
. Sustained axial distraction
. Repetitive lateral compression

Correct Answer & Explanation

. Repetitive hyperextension and rotational shear stress

Explanation

Correct Answer: BSpondylolysis is a stress fracture of the pars interarticularis, most commonly occurring in the lower lumbar spine (L5). It is classically caused by repetitive hyperextension and rotational forces, which place maximal shear stress on the pars. This is frequently seen in adolescent athletes such as gymnasts, weightlifters, and football linemen.

Question 7467

Topic: 6. Spine

A 15-year-old competitive gymnast presents with chronic, insidious-onset low back pain that is exacerbated by arching her back. Radiographs reveal a defect in the pars interarticularis of L5. Which of the following biomechanical forces is the primary driver for the development of this specific injury?

. Axial loading in a neutral spine position
. Repetitive flexion and lateral bending
. Repetitive hyperextension and rotation
. Acute hyperflexion with a rotational moment
. Distraction and shear forces during rapid growth

Correct Answer & Explanation

. Repetitive hyperextension and rotation

Explanation

Correct Answer: Repetitive hyperextension and rotationSpondylolysis is a stress fracture or defect of the pars interarticularis, most commonly occurring at L5. It is classically seen in adolescent athletes who participate in sports requiring repetitive hyperextension and rotational stresses across the lumbar spine, such as gymnastics, weightlifting, and football (linemen). These forces concentrate stress on the pars, leading to microtrauma and eventual fracture.

Question 7468

Topic: Thoracolumbar Spine & Deformity

A 15-year-old gymnast presents with an insidious onset of low back pain that is exacerbated by extension activities. Radiographs reveal a defect in the pars interarticularis. Which of the following biomechanical forces is most directly responsible for the development of this specific lesion?

. Repetitive axial loading in a flexed posture
. Repetitive hyperextension and rotational shear
. Acute hyperflexion with lateral bending
. Sustained axial distraction
. Repetitive lateral flexion in a neutral sagittal plane

Correct Answer & Explanation

. Repetitive hyperextension and rotational shear

Explanation

Correct Answer: Repetitive hyperextension and rotational shearSpondylolysis is a stress fracture or defect of the pars interarticularis. It most commonly occurs in adolescent athletes who participate in sports requiring repetitive hyperextension and rotation of the lumbar spine, such as gymnastics, weightlifting, and football. These repetitive forces lead to microtrauma and subsequent stress fracture of the pars interarticularis.

Question 7469

Topic: 6. Spine

A 15-year-old gymnast presents with an insidious onset of low back pain that is exacerbated by back extension. Radiographs reveal a defect in the pars interarticularis of L5. Which of the following biomechanical forces is the primary contributor to the development of this specific lesion?

. Axial loading in a flexed position
. Repetitive hyperextension and rotation
. Acute hyperflexion with lateral bending
. Distraction and shear forces
. Repetitive axial compression

Correct Answer & Explanation

. Repetitive hyperextension and rotation

Explanation

Correct Answer: BSpondylolysis is a stress fracture or defect in the pars interarticularis, most commonly occurring in the lower lumbar spine (L5). It is classically caused by repetitive hyperextension and rotation forces across the lumbar spine. This mechanism is particularly common in adolescent athletes participating in sports such as gymnastics, weightlifting, and football linemen. Initial imaging includes plain radiographs (AP, lateral, and oblique views), where the defect may appear as a 'Scotty dog with a collar' on the oblique view.

Question 7470

Topic: 6. Spine

A 25-year-old male is brought to the emergency department after a diving accident, presenting with C5 tetraplegia. He is noted to be hypotensive and bradycardic, yet his extremities are warm and well-perfused. Which of the following best describes this patient's current hemodynamic state?

. Hypovolemic shock
. Spinal shock
. Neurogenic shock
. Cardiogenic shock
. Septic shock

Correct Answer & Explanation

. Neurogenic shock

Explanation

Neurogenic shock is a hemodynamic phenomenon characterized by hypotension and bradycardia due to loss of sympathetic tone following cervical or high thoracic spinal cord injury. Spinal shock is a distinct neurologic phenomenon defined by the temporary loss of all spinal cord reflexes below the level of injury.

Question 7471

Topic: 6. Spine

While examining a patient for suspected cervical spondylotic myelopathy, the examiner assesses for a Hoffmann sign. A positive response, which indicates an upper motor neuron lesion, consists of reflex flexion of the thumb IP joint elicited by which specific maneuver?

. Tapping the volar aspect of the wrist over the median nerve
. Flicking the distal phalanx of the middle finger into sudden flexion
. Scraping the lateral aspect of the plantar surface of the foot
. Rapidly, forcefully dorsiflexing the patient's ankle
. Striking the brachioradialis tendon with a reflex hammer

Correct Answer & Explanation

. Flicking the distal phalanx of the middle finger into sudden flexion

Explanation

The Hoffmann test is performed by flicking the nail of the patient's middle finger downward into flexion. A positive sign is the reflexive flexion of the interphalangeal joint of the thumb and/or index finger, indicating an upper motor neuron lesion such as cervical myelopathy.

Question 7472

Topic: 6. Spine

A 65-year-old female with long-standing rheumatoid arthritis presents with increasing clumsiness in her hands and difficulty walking. Radiographs of the cervical spine demonstrate atlantoaxial subluxation. Which of the following radiographic measurements is the most reliable predictor of impending neurologic injury?

. Anterior atlantodental interval (ADI) > 3 mm
. Anterior atlantodental interval (ADI) > 9 mm
. Posterior atlantodental interval (PADI) < 14 mm
. Cervical lordosis angle < 10 degrees
. Subaxial translation > 2 mm

Correct Answer & Explanation

. Posterior atlantodental interval (PADI) < 14 mm

Explanation

The posterior atlantodental interval (PADI), which estimates the available space for the spinal cord (SAC), is the most reliable predictor of neurologic recovery and injury in RA patients. A PADI of less than 14 mm correlates strongly with an increased risk of neurologic compromise.

Question 7473

Topic: 6. Spine

A 55-year-old diabetic male presents with insidious onset of severe, unrelenting back pain that is worse at night, accompanied by low-grade fevers. MRI of the lumbar spine with contrast shows narrowing of the L4-L5 disc space, endplate destruction, and enhancement of the adjacent vertebral bodies. Blood cultures are pending. What is the next best step in management?

. Immediate open anterior debridement and fusion
. Empiric administration of broad-spectrum intravenous antibiotics
. CT-guided needle biopsy of the affected disc space
. Posterior lumbar laminectomy for neural decompression
. Observation and bracing with a thoracolumbosacral orthosis (TLSO)

Correct Answer & Explanation

. CT-guided needle biopsy of the affected disc space

Explanation

In the absence of a progressive neurologic deficit or hemodynamic instability, the standard of care for suspected pyogenic spondylodiscitis is obtaining a tissue diagnosis via CT-guided biopsy. Empiric antibiotics should be strictly withheld if the patient is stable to maximize the microbiologic yield of the biopsy.

Question 7474

Topic: 6. Spine

A 9-year-old patient with Spondyloepiphyseal Dysplasia (SED) congenita is scheduled for elective lower extremity osteotomies. Which of the following preoperative evaluations is absolutely critical to prevent a catastrophic perioperative complication?

. Echocardiogram
. Cervical spine flexion-extension radiographs
. Renal ultrasound
. Pulmonary function tests

Correct Answer & Explanation

. Cervical spine flexion-extension radiographs

Explanation

Correct Answer: Cervical spine flexion-extension radiographsPatients with Spondyloepiphyseal Dysplasia (SED) congenita frequently have odontoid hypoplasia, which can lead to severe atlantoaxial instability. Flexion-extension radiographs of the cervical spine are mandatory before any surgery requiring general anesthesia and intubation to prevent iatrogenic spinal cord injury during neck manipulation.

Question 7475

Topic: 6. Spine
Which of the following clinical features is typically absent in a patient with classic Multiple Epiphyseal Dysplasia (MED)?
. Premature osteoarthritis
. Short-trunk dwarfism
. Mild to moderate short stature
. Joint pain and stiffness in childhood

Correct Answer & Explanation

. Short-trunk dwarfism

Explanation

Classic Multiple Epiphyseal Dysplasia (MED) primarily affects the epiphyses of the long bones, leading to mild to moderate short stature (often short-limbed), joint pain, and premature osteoarthritis. The spine is typically spared or only very mildly affected, so short-trunk dwarfism is absent. Short-trunk dwarfism is a hallmark of Spondyloepiphyseal Dysplasia (SED).

Question 7476

Topic: 6. Spine

A 5-year-old child with Spondyloepiphyseal Dysplasia Congenita (SEDC) is scheduled for bilateral hip reconstruction for severe coxa vara. During the preoperative assessment, which of the following evaluations is most critical to perform before proceeding with general anesthesia?

. Echocardiogram to rule out aortic root dilation
. Flexion-extension cervical spine radiographs
. Renal ultrasound to rule out horseshoe kidney
. Pulmonary function tests
. MRI of the lumbar spine to assess for tethered cord

Correct Answer & Explanation

. Flexion-extension cervical spine radiographs

Explanation

Correct Answer: B (Flexion-extension cervical spine radiographs)Spondyloepiphyseal Dysplasia Congenita (SEDC) is associated with odontoid hypoplasia, which can lead to severe atlantoaxial instability. Preoperative flexion-extension cervical spine radiographs are critical to assess for instability before intubation and neck positioning to prevent catastrophic spinal cord injury. Aortic root dilation is associated with Marfan syndrome, not SEDC.

Question 7477

Topic: 6. Spine

A 9-year-old child presents with joint pain and mild short stature. The orthopedic surgeon is trying to differentiate between Multiple Epiphyseal Dysplasia (MED) and Spondyloepiphyseal Dysplasia (SED). Which of the following radiographic findings of the spine would most strongly support a diagnosis of MED over SED?

. Severe platyspondyly with central anterior beaking
. Odontoid hypoplasia
. Normal vertebral body height with mild endplate irregularities
. Bullet-shaped vertebrae at the thoracolumbar junction
. Posterior scalloping of the lumbar vertebrae

Correct Answer & Explanation

. Normal vertebral body height with mild endplate irregularities

Explanation

Correct Answer: C (Normal vertebral body height with mild endplate irregularities)The key differentiating factor between MED and SED is the degree of spinal involvement. In MED, the spine is typically normal or shows only mild irregularities (e.g., Schmorl's nodes, mild endplate changes), and stature is only mildly affected. In SED, there is significant spinal involvement, typically presenting as platyspondyly (flattened vertebrae) leading to short trunk dwarfism.

Question 7478

Topic: 6. Spine

A 6-year-old boy presents with waddling gait, joint pain, and short stature. Radiographs reveal delayed, irregular ossification of multiple epiphyses. Genetic testing confirms a mutation in the COMP (Cartilage Oligomeric Matrix Protein) gene. Which of the following radiographic findings is most classically associated with this patient's condition?

. Severe platyspondyly with anterior beaking
. Double-layer patella on lateral knee radiograph
. Stippled epiphyses of the proximal femur
. Erlenmeyer flask deformity of the distal femur
. Rugger jersey spine

Correct Answer & Explanation

. Double-layer patella on lateral knee radiograph

Explanation

Correct Answer: Double-layer patella on lateral knee radiographThis patient has Multiple Epiphyseal Dysplasia (MED), most commonly caused by mutations in the COMP gene (Fairbank type). A classic, though not entirely pathognomonic, radiographic finding in MED is the 'double-layer' patella seen on a lateral knee radiograph. Severe platyspondyly is characteristic of Spondyloepiphyseal Dysplasia (SED), not MED. Stippled epiphyses are seen in Chondrodysplasia Punctata. Erlenmeyer flask deformity is seen in osteopetrosis and Gaucher disease. Rugger jersey spine is associated with renal osteodystrophy.

Question 7479

Topic: 6. Spine

A 5-year-old child with Spondyloepiphyseal Dysplasia Congenita (SEDC) is scheduled for bilateral proximal femoral osteotomies to treat severe coxa vara. Which of the following preoperative evaluations is absolutely mandatory before proceeding with surgery?

. Echocardiogram to rule out aortic root dilation
. Renal ultrasound to rule out polycystic kidneys
. Cervical spine flexion-extension radiographs
. Pulmonary function tests
. Cranial MRI to rule out Chiari malformation

Correct Answer & Explanation

. Cervical spine flexion-extension radiographs

Explanation

Correct Answer: Cervical spine flexion-extension radiographsSpondyloepiphyseal Dysplasia Congenita (SEDC) is a type II collagenopathy (COL2A1 mutation). It is strongly associated with odontoid hypoplasia and os odontoideum, leading to atlantoaxial instability. Preoperative cervical spine clearance with flexion-extension radiographs is mandatory before any procedure requiring anesthesia and intubation to prevent catastrophic spinal cord injury. Aortic root dilation is associated with Marfan syndrome, not SEDC.

Question 7480

Topic: 6. Spine

When differentiating Multiple Epiphyseal Dysplasia (MED) from Spondyloepiphyseal Dysplasia (SED) radiographically, which of the following findings is the most reliable distinguishing feature?

. The presence of coxa vara is exclusive to MED.
. MED typically lacks significant spinal involvement, whereas SED features marked platyspondyly.
. SED is characterized by severe metaphyseal flaring, which is absent in MED.
. MED always presents with atlantoaxial instability, whereas SED does not.
. SED exclusively affects the appendicular skeleton, sparing the axial skeleton.

Correct Answer & Explanation

. MED typically lacks significant spinal involvement, whereas SED features marked platyspondyly.

Explanation

Correct Answer: MED typically lacks significant spinal involvement, whereas SED features marked platyspondyly.The primary distinguishing feature between MED and SED is the extent of spinal involvement. MED primarily affects the epiphyses of the appendicular skeleton, and spinal involvement is usually absent or very mild (e.g., mild endplate irregularities). In contrast, SED (Spondyloepiphyseal Dysplasia) inherently involves the spine, classically presenting with marked platyspondyly (flattened vertebrae) and other axial deformities.

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