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 6601
Topic: Cervical Spine
A 22-year-old collegiate baseball pitcher complains of medial elbow pain during the late cocking phase of throwing. What is the primary restraint to valgus stress at the elbow during this specific phase of the throwing motion?
Correct Answer & Explanation
. Anterior bundle of the ulnar collateral ligament
Explanation
The anterior bundle of the ulnar collateral ligament (UCL) is the primary restraint to valgus stress at the elbow between 30 and 120 degrees of flexion. This corresponds to the late cocking and early acceleration phases of throwing where valgus forces are highest.
Question 6602
Topic: 6. Spine
During an anterior approach to the thoracolumbar spine for a burst fracture corpectomy, segmental vessels are ligated. The Artery of Adamkiewicz is primarily responsible for supplying the anterior spinal artery in the lower thoracic and lumbar regions. Typically, on which side and between which spinal levels does this artery most commonly originate?
Correct Answer & Explanation
. Left side, T9-L1
Explanation
The Artery of Adamkiewicz (arteria radicularis magna) most commonly arises on the left side between the levels of T9 and L1 (in about 75-80% of cases). Ligation or injury to this vessel during anterior spinal approaches can lead to anterior spinal artery syndrome (ischemia of the anterior spinal cord resulting in paraplegia with preserved dorsal column function).
Question 6603
Topic: 6. Spine
When planning posterior instrumented spinal fusion, understanding lumbar pedicle morphology is critical. Which lumbar vertebral level typically has the widest pedicle diameter in the coronal plane?
Correct Answer & Explanation
. L5
Explanation
Pedicle width in the coronal plane steadily increases from L1 to L5. L5 has the widest pedicles, typically allowing for the placement of larger diameter pedicle screws compared to the upper lumbar spine.
Question 6604
Topic: 6. Spine
The alar ligaments are strong fibrous bands that connect the dens to the occipital condyles. What is their primary biomechanical function at the craniocervical junction?
Correct Answer & Explanation
. Limit axial rotation and lateral flexion of the cranium on the axis
Explanation
The alar ligaments run obliquely from the superolateral aspect of the dens to the medial aspects of the occipital condyles. Their primary function is to limit contralateral axial rotation and lateral flexion of the occiput and C1 on C2. The transverse ligament prevents anterior translation of C1 on C2.
Question 6605
Topic: 6. Spine
A 16-year-old male presents with back pain, leg weakness, and a sacral mass. Biopsy confirms Ewing's Sarcoma. What is the immediate concern for neurological function?
Correct Answer & Explanation
. Imminent spinal cord compression
Explanation
A sacral mass with leg weakness points to potential spinal cord or cauda equina compression, which is an oncologic emergency requiring urgent evaluation (MRI spine) and often emergent treatment (radiation or surgical decompression) to preserve neurological function. Peripheral neuropathy is a side effect of certain chemotherapeutic agents (e.g., vincristine) but not an immediate concern related to the mass itself. The other options are not directly related to a sacral mass with leg weakness.
Question 6606
Topic: 6. Spine
A patient with an Aneurysmal Bone Cyst in the cervical spine presents with new onset of upper extremity paresthesias and weakness. What imaging study is most critical to evaluate this acute change?
Correct Answer & Explanation
. Magnetic Resonance Imaging (MRI) of the cervical spine.
Explanation
For evaluating new onset neurological deficits in the context of a spinal lesion, Magnetic Resonance Imaging (MRI) of the affected spinal segment is most critical. MRI provides unparalleled soft tissue contrast, allowing for detailed assessment of spinal cord compression, nerve root impingement, and intraspinal extension of the tumor, which plain radiographs and CT alone cannot adequately visualize. A CT myelogram can also show impingement but is invasive, and MRI is typically preferred as the primary non-invasive study.
Question 6607
Topic: 6. Spine
Which of the following describes the 'safe corridor' for percutaneous iliosacral screw placement, as it relates to minimizing neurological injury?
Correct Answer & Explanation
. Within the S1 vertebral body, directed from the posterior superior iliac spine into the sacral ala
Explanation
The 'safe corridor' for S1 iliosacral screw placement involves directing the screw from the posterior superior iliac spine (PSIS) region, through the thickest part of the S1 sacral ala, and into the S1 vertebral body, while staying within the cortical boundaries. Critically, it must remain lateral to the S1 foramen and anterior to the sacral canal to avoid neurological structures (S1 nerve root). Placement lateral to the S1 foramen and inferior to the superior gluteal neurovascular bundle is relevant for more lateral fixations, but the primary 'safe corridor' is within the S1 body.
Question 6608
Topic: 6. Spine
A 55-year-old male presents with a painful expanding lesion in the lumbar spine. MRI shows a destructive lesion at L3 with epidural extension. Prior to biopsy, it is essential to consider the stability of the spine. Which of the following is the BEST indicator of spinal instability secondary to a tumor?
Correct Answer & Explanation
. The 'load-sharing' classification system (e.g., Tomita or Tokuhashi score).
Explanation
While neurological deficit, tumor size, and soft tissue extension are important, the 'load-sharing' classification systems (e.g., Tomita, Tokuhashi) are specifically designed to assess spinal stability in the context of metastatic or primary tumor involvement. These scores consider factors like the number of spinal segments involved, location of the tumor (vertebral body, posterior elements), and degree of vertebral body collapse, providing a prognostic and surgical planning tool for stability. Plain radiographs can show collapse but don't provide a comprehensive stability assessment. Neurological deficit indicates neural compromise, not solely mechanical instability.
Question 6609
Topic: 6. Spine
Which of the following statements about the clinical presentation of spinal meningiomas is FALSE?
Correct Answer & Explanation
. They are commonly associated with Neurofibromatosis Type 1.
Explanation
Spinal meningiomas are indeed more common in women (especially perimenopausal), typically cause slow, progressive deficits, and are most prevalent in the thoracic spine, often presenting with radicular pain. However, they are strongly associated with Neurofibromatosis Type 2 (NF2), not Type 1 (NF1). NF1 is more commonly associated with neurofibromas and optic pathway gliomas.
Question 6610
Topic: 6. Spine
What is the typical presentation of an osteoblastoma of the spine?
Correct Answer & Explanation
. Severe back pain, often worse at night, not consistently relieved by NSAIDs, often associated with a painful scoliosis if in children.
Explanation
Osteoblastomas are benign bone-forming tumors that are histologically similar to osteoid osteomas but are larger (>1.5-2 cm) and generally less sclerotic. Unlike osteoid osteomas, the pain associated with osteoblastomas is often severe, poorly responsive to NSAIDs, and can be worse at night. Spinal osteoblastomas frequently involve the posterior elements and can cause a painful scoliosis, particularly in children and adolescents, due to muscle spasm. Night pain relieved by NSAIDs is characteristic of osteoid osteoma. Other options describe other conditions like disc herniation or spinal stenosis.
Question 6611
Topic: 6. Spine
A patient is undergoing an en bloc spondylectomy for a primary malignant tumor of the thoracic spine. Which of the following intraoperative neuromonitoring modalities is most critical for detecting early spinal cord compromise?
Correct Answer & Explanation
. Motor Evoked Potentials (MEPs)
Explanation
During complex spinal surgeries, especially those involving tumor resection and potential spinal cord manipulation, MEPs are crucial. MEPs directly assess the integrity of the descending motor pathways (corticospinal tracts) and are highly sensitive to detect ischemic or mechanical injury to the motor tracts. SSEPs monitor ascending sensory pathways but may not detect pure motor deficits. EMG monitors nerve root function. NCS is typically pre-operative. EEG is for brain activity. Therefore, MEPs are paramount for monitoring motor function during en bloc spondylectomy.
Question 6612
Topic: 6. Spine
What is the most frequent initial symptom of a primary spinal cord tumor (intramedullary)?
Correct Answer & Explanation
. Progressive sensory changes and gait disturbance
Explanation
Intramedullary spinal cord tumors (e.g., ependymomas, astrocytomas) typically grow slowly, causing insidious and progressive neurological deficits. Common initial symptoms include progressive sensory changes (numbness, paresthesias), gait disturbance, and motor weakness, often in a long-tract pattern. Acute onset paraplegia is rare. While localized pain can occur, it's often not the sole or most prominent feature initially. Radicular pain is more common with intradural-extramedullary or extradural lesions. Cauda equina syndrome is specific to lower lumbar/sacral regions, typically from conus or filum terminale tumors.
Question 6613
Topic: 6. Spine
In the Magerl-AO classification system for spinal fractures, which type of fracture is typically associated with a significantly increased risk of neurological injury when present with a tumor?
Correct Answer & Explanation
. Type C (Translational injuries)
Explanation
The Magerl-AO classification system categorizes spinal fractures based on mechanism and stability. Type C fractures, representing translational injuries, involve disruption of all three spinal columns and are highly unstable. When associated with a tumor, these translational forces can lead to significant displacement and a very high risk of severe neurological injury due to direct impingement and shear forces on the spinal cord or cauda equina. While burst fractures (A3) also carry neurological risk, Type C represents a much higher degree of instability and neurological compromise.
Question 6614
Topic: 6. Spine
A 40-year-old male with a history of intravenous drug use and HIV presents with acute back pain, fever, and progressive paraparesis. MRI shows a L3 vertebral body lesion with epidural extension and significant cord compression. Given the clinical context, what is the most likely diagnosis, and what is the initial management priority after obtaining imaging?
Correct Answer & Explanation
. Pyogenic vertebral osteomyelitis with epidural abscess; urgent surgical decompression and debridement with antibiotics.
Explanation
The clinical presentation (acute pain, fever, paraparesis, IVDU/HIV risk factors) combined with imaging of a destructive vertebral lesion and epidural compression points strongly towards pyogenic vertebral osteomyelitis with an epidural abscess. This is a surgical emergency requiring urgent decompression of the spinal cord (laminectomy or anterior debridement) and debridement of infected tissue, along with empiric broad-spectrum antibiotics, to prevent irreversible neurological damage and control infection. While other options represent potential diagnoses, the acute febrile presentation and risk factors make infection most likely and prioritize urgent surgical source control.
Question 6615
Topic: 6. Spine
What is the approximate percentage of patients with systemic cancer who will develop spinal metastases?
Correct Answer & Explanation
. 30-40%
Explanation
Spinal metastases are a very common complication of systemic cancer. It is estimated that approximately 30-40% of patients with systemic cancer will develop spinal metastases during their disease course. This number varies depending on the type of primary cancer, but the spine is the most common site of bone metastasis. Options A and B are too low, and options D and E are too high as a general estimate.
Question 6616
Topic: 6. Spine
Which of the following describes the most common location for primary spinal astrocytomas in adults?
Correct Answer & Explanation
. Cervical spine
Explanation
Spinal cord astrocytomas, like ependymomas, are intramedullary tumors. While they can occur anywhere, they show a slight predilection for the cervical and cervicothoracic regions in adults. Ependymomas are more common at the conus medullaris/filum terminale. Therefore, cervical spine is the most common location for primary spinal astrocytomas in adults.
Question 6617
Topic: 6. Spine
A patient develops new onset of bladder dysfunction and saddle anesthesia following surgery for an intradural-extramedullary lumbar spine tumor. These symptoms are most indicative of injury to which of the following structures?
Correct Answer & Explanation
. Cauda equina
Explanation
Bladder dysfunction (urinary retention or incontinence) and saddle anesthesia (loss of sensation in the perineal and inner thigh region) are classic symptoms of cauda equina syndrome. In the lumbar spine, below the conus medullaris (typically L1-L2), the spinal cord terminates, and the nerve roots of the cauda equina descend. Injury to these nerve roots during surgery for a lumbar intradural-extramedullary tumor (e.g., schwannoma, meningioma) can cause these deficits. Injury to the spinal cord itself would cause upper motor neuron signs (spasticity, hyperreflexia). Cervical or thoracic nerve roots would present with different neurological deficits.
Question 6618
Topic: 6. Spine
What is the typical age group and spinal location for a spinal hemangioblastoma?
Correct Answer & Explanation
. Young to middle-aged adults, thoracic or cervicomedullary junction
Explanation
Spinal hemangioblastomas are rare, benign, highly vascular intramedullary tumors. They are most commonly seen in young to middle-aged adults, and their most frequent location is the thoracic spine, followed by the cervicomedullary junction and cervical spine. They are often associated with Von Hippel-Lindau (VHL) disease, in which case they can be multifocal. Pediatric cases are rare, and elderly onset is less common. Diffuse multifocal throughout the entire spine is primarily seen in VHL. Therefore, young to middle-aged adults, thoracic or cervicomedullary junction, is the most typical.
Question 6619
Topic: 6. Spine
What is the primary pathophysiological mechanism hypothesized to cause neurogenic claudication symptoms in lumbar spinal stenosis?
Correct Answer & Explanation
. Ischemia of the cauda equina nerve roots due to compromised blood supply.
Explanation
While several factors contribute, the primary pathophysiological mechanism causing neurogenic claudication is thought to be ischemia of the cauda equina nerve roots. With spinal canal narrowing, the blood supply to the nerve roots (especially the radicular arteries and venous outflow) becomes compromised, particularly during activity when metabolic demands increase. This leads to transient ischemia and nerve dysfunction, manifesting as pain, numbness, and weakness. Mechanical compression and inflammation also play roles, but ischemia is considered central to the claudication symptoms. Direct compression of the spinal cord (Option D) is not applicable at the lumbar level in adults. Venous congestion (Option E) is part of the ischemic process.
Question 6620
Topic: 6. Spine
Which of the following physical exam maneuvers is most likely to exacerbate symptoms in a patient with lumbar spinal stenosis?
Correct Answer & Explanation
. Sustained lumbar extension for 30-60 seconds.
Explanation
Sustained lumbar extension (e.g., standing upright, walking downhill, or the prone extension test) narrows the spinal canal and neuroforamina, thereby exacerbating symptoms in patients with lumbar spinal stenosis. Options A and C are more relevant for disc herniation/radiculopathy. Walking on an incline (Option B) often makes symptomsbetterin stenosis as it encourages a more flexed posture. Sitting with hips and knees flexed (Option E) is a classic relieving position for neurogenic claudication.
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