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 6901
Topic: 6. Spine
Which of the following physical examination findings is the most sensitive indicator of early cauda equina syndrome in a patient presenting with acute low back pain and bilateral radiculopathy?
Correct Answer & Explanation
. Urinary retention
Explanation
Urinary retention is the most sensitive and often the earliest sign of cauda equina syndrome, leading to overflow incontinence as the bladder overfills. Post-void residual ultrasound showing > 100-200 mL strongly supports the diagnosis in the acute setting.
Question 6902
Topic: 6. Spine
During a neurologic examination of a patient with suspected cervical spondylotic myelopathy, you perform the brachioradialis reflex. Tapping the brachioradialis tendon produces a diminished reflex response in the forearm but elicits spontaneous flexion of the fingers. This 'inverted supinator reflex' indicates compression at which of the following spinal cord levels?
Correct Answer & Explanation
. C5-C6
Explanation
The inverted supinator reflex (or inverted brachioradialis reflex) is a classic upper motor neuron sign suggestive of cervical myelopathy. It localizes the lesion to the C5-C6 level. The absent normal response (brachioradialis jerk) is due to a lower motor neuron lesion at C6, while the hyperactive finger flexion (an uninhibited C8 response) is an upper motor neuron sign indicating cord compression at the C5-C6 level affecting descending tracts.
Question 6903
Topic: 6. Spine
A patient sustains a severe cervical spine trauma resulting in absent motor, sensory, and reflex activity below the level of injury. In the acute setting, accurate determination of a complete versus incomplete spinal cord injury (via ASIA scoring) cannot be established until spinal shock has resolved. The resolution of spinal shock is heralded by the return of which of the following?
Correct Answer & Explanation
. The bulbocavernosus reflex
Explanation
Spinal shock is a physiologic concussion of the spinal cord resulting in flaccid paralysis, areflexia, and lack of sensation below the level of injury. Its resolution is traditionally marked by the return of the bulbocavernosus reflex (an S1-S3 reflex). Once this reflex returns, the spinal cord is no longer in 'shock', and the patient's neurologic deficit can be accurately classified as a complete or incomplete injury.
Question 6904
Topic: 6. Spine
In patients presenting with Cauda Equina Syndrome, which of the following is the most consistent and significant predictor of postoperative bladder function recovery?
Correct Answer & Explanation
. Preoperative degree of bladder dysfunction
Explanation
The most consistent and significant predictor of postoperative bladder recovery in cauda equina syndrome is the severity of preoperative bladder dysfunction (e.g., partial vs. complete retention with overflow incontinence). While early surgical decompression is critical, preoperative neurological status remains the strongest prognostic factor for long-term recovery.
Question 6905
Topic: 6. Spine
A 65-year-old man with cervical spondylosis presents with progressive clumsiness in his hands and a broad-based gait. He is unable to continue working as a mechanic due to his walking difficulties, but he remains able to ambulate independently without a cane or walker. What is his Nurick classification grade?
Correct Answer & Explanation
. Grade 3
Explanation
The Nurick classification grades cervical spondylotic myelopathy based on gait and employment. Grade 0: Root signs only. Grade 1: Cord signs, normal gait. Grade 2: Mild gait impairment, but employed. Grade 3: Gait abnormality prevents employment, but ambulatory without assistance. Grade 4: Ambulatory only with assistance. Grade 5: Wheelchair/bedbound.
Question 6906
Topic: 6. Spine
A 72-year-old female presents with severe debilitating low back pain, sagittal imbalance, and neurogenic claudication. Radiographs show a >60-degree thoracolumbar kyphosis, significant lumbar scoliosis, and degenerative spondylolisthesis at L4-L5. She has failed extensive conservative management. Surgical correction is planned. Which of the following principles is most crucial in determining the proximal fusion level for optimal long-term outcomes in this patient?
Correct Answer & Explanation
. Fusing to the upper thoracic spine (e.g., T4 or higher) if significant thoracic kyphosis or shoulder imbalance is present
Explanation
In severe adult spinal deformity with significant sagittal and coronal imbalance, especially in elderly patients, the choice of the proximal fusion level is critical to prevent proximal junctional kyphosis (PJK) or proximal junctional failure (PJF). Fusing too short proximally can lead to breakdown above the construct. Current best practices often advocate extending the fusion to the upper thoracic spine (e.g., T4 or higher) when there is significant cervicothoracic kyphosis, global sagittal malalignment, or if the patient has shoulder imbalance, to ensure global balance and distribute stress over a longer construct, thereby reducing the risk of PJK/PJF. Fusing only to the stable vertebra or T10 might be too short for severe deformity. Terminating at T12-L1 is rarely appropriate for severe deformity correction. Coronal balance is important, but sagittal balance and the prevention of PJK/PJF often dictate a higher proximal fusion.
Question 6907
Topic: 6. Spine
A 65-year-old male presents with progressive hand clumsiness, frequent falls, and a broad-based gait. Physical exam reveals a positive Hoffman's sign. MRI shows multilevel cervical stenosis with spinal cord signal change. What is the primary goal of surgical intervention?
Correct Answer & Explanation
. Prevention of neurological progression
Explanation
Cervical spondylotic myelopathy is a progressively deteriorating condition. The primary goal of surgical decompression is to halt the progression of neurological decline, though some patients may experience mild functional recovery.
Question 6908
Topic: 6. Spine
A 70-year-old male presents with bilateral leg heaviness that worsens with standing, but improves when he leans forward on a shopping cart. Peripheral pulses are normal. What is the most appropriate initial diagnostic imaging modality?
Correct Answer & Explanation
. MRI of the lumbar spine without contrast
Explanation
The patient's symptoms are classic for neurogenic claudication secondary to lumbar spinal stenosis. MRI of the lumbar spine without contrast is the gold standard imaging modality to evaluate central canal and foraminal stenosis.
Question 6909
Topic: 6. Spine
A 42-year-old female presents with acute onset severe lower back pain, bilateral sciatica, saddle anesthesia, and urinary retention. Post-void residual volume is 600 mL. MRI demonstrates a massive central L4-L5 disc herniation compressing the thecal sac. What is the recommended timeframe for surgical intervention to optimize neurological recovery?
Correct Answer & Explanation
. Within 24 hours, ideally within 8 hours
Explanation
Cauda equina syndrome is a surgical emergency. Decompression should ideally be performed within 24 hours, and evidence suggests best outcomes when done within 8 hours, to maximize the recovery of bladder and bowel function.
Question 6910
Topic: 6. Spine
A 35-year-old male falls from a height of 10 feet. He is neurologically intact. CT scan shows an L1 burst fracture with 15% loss of anterior vertebral body height, 10 degrees of regional kyphosis, and 20% retropulsion into the spinal canal. Posterior ligamentous complex is intact on MRI. What is the most appropriate management?
Correct Answer & Explanation
. Thoracolumbosacral orthosis (TLSO) brace
Explanation
This L1 burst fracture is considered stable, given the intact posterior ligamentous complex, lack of neurological deficit, mild kyphosis (<30 degrees), and minimal loss of vertebral height (<50%). Such stable burst fractures are successfully treated non-operatively with a TLSO brace and early mobilization.
Question 6911
Topic: 6. Spine
A 45-year-old male presents with acute urinary retention, saddle anesthesia, and bilateral lower extremity weakness following a heavy lifting injury. MRI confirms a massive L4-L5 disc herniation compressing the cauda equina. Surgical decompression is planned. Which factor most strongly correlates with a favorable return of bladder function?
Correct Answer & Explanation
. Time to decompression less than 48 hours from symptom onset
Explanation
Cauda equina syndrome is a surgical emergency. Decompression within 48 hours of symptom onset (particularly before the development of painless urinary retention) provides the highest likelihood of neurological recovery and return of bladder control.
Question 6912
Topic: 6. Spine
A 65-year-old male presents with progressive hand clumsiness, gait instability, and hyperreflexia. MRI reveals cervical spinal stenosis at C4-C5 with myelomalacia. Which physical exam finding is most closely associated with this condition?
Correct Answer & Explanation
. Hoffman sign
Explanation
The Hoffman sign indicates an upper motor neuron lesion and is a classic finding in cervical spondylotic myelopathy. The Spurling sign is specific for cervical radiculopathy, whereas Lhermitte sign is classically seen in multiple sclerosis but can occur in myelopathy.
Question 6913
Topic: Thoracolumbar Spine & Deformity
A 14-year-old gymnast presents with chronic low back pain exacerbating with extension. Radiographs show a grade II isthmic spondylolisthesis at L5-S1. Despite 6 months of physical therapy and bracing, pain persists and prevents sports participation. What is the most appropriate surgical treatment?
Correct Answer & Explanation
. L5-S1 posterior instrumented fusion
Explanation
For a symptomatic high-grade or progressive isthmic spondylolisthesis failing nonoperative care, an L5-S1 posterior instrumented fusion is the gold standard. Direct pars repair is generally reserved for younger patients with a pars defect but minimal to no listhesis (Grade 0 or early Grade I).
Question 6914
Topic: 6. Spine
A 65-year-old man presents with deteriorating fine motor skills, hand clumsiness, and an unsteady, broad-based gait. Examination reveals a positive Hoffmann sign bilaterally. MRI demonstrates severe cervical spinal stenosis at C4-C5 and C5-C6 with cord compression. Which of the following is the most critical prognostic factor for his functional recovery following decompressive surgery?
Correct Answer & Explanation
. Duration of symptoms prior to surgical intervention
Explanation
In cases of cervical spondylotic myelopathy, the duration of neurological symptoms before surgical decompression is the most robust and critical predictor of postoperative recovery. Prolonged symptom duration leads to irreversible spinal cord damage, highlighting the need for prompt surgical intervention.
Question 6915
Topic: 6. Spine
A 60-year-old woman with long-standing rheumatoid arthritis complains of occipital headaches and upper extremity paresthesias. Flexion-extension cervical spine radiographs reveal an anterior atlantodens interval (ADI) of 8 mm. What is the most appropriate next step in management?
Correct Answer & Explanation
. Posterior C1-C2 fusion
Explanation
An ADI > 3 mm in adults indicates C1-C2 instability. Because this patient is symptomatic (myelopathy/headaches) and her ADI is > 5 mm, she is at high risk for catastrophic neurologic compromise. A posterior C1-C2 fusion is indicated. Occipitocervical fusion is typically reserved for cranial settling (vertical migration).
Question 6916
Topic: 6. Spine
A 5-year-old boy presents with bone pain, petechiae, and swollen gums. Radiographs of the knee show a dense zone of provisional calcification (white line of Frankel) and a radiolucent zone adjacent to the physis (Trummerfeld zone). The pathogenesis of this condition is due to a failure in which of the following processes?
Correct Answer & Explanation
. Hydroxylation of proline and lysine residues
Explanation
The clinical and radiographic findings describe Scurvy (Vitamin C deficiency). Vitamin C is a required cofactor for prolyl hydroxylase and lysyl hydroxylase, which are responsible for the hydroxylation of proline and lysine residues during collagen synthesis. This defect weakens the structural integrity of collagen.
Question 6917
Topic: 6. Spine
A 45-year-old immigrant presents with a severe, unilateral lower extremity deformity characterized by a flail limb, fixed equinus, and profound muscle atrophy. Sensation in the limb is completely normal. He reports having a severe febrile illness followed by paralysis as a child. What is the primary pathologic target of the infectious agent responsible for this patient's condition?
Correct Answer & Explanation
. Anterior horn cells of the spinal cord
Explanation
The clinical picture of asymmetric flaccid paralysis with intact sensation from a childhood illness suggests Poliomyelitis. The poliovirus specifically targets and destroys the anterior horn cells (motor neurons) in the spinal cord, leading to pure lower motor neuron signs without any sensory deficits.
Question 6918
Topic: 6. Spine
In a patient with advanced cervical spondylotic myelopathy, which of the following magnetic resonance imaging (MRI) findings of the spinal cord is most highly predictive of a poor potential for clinical recovery following surgical decompression?
Correct Answer & Explanation
. T1 hypointensity combined with T2 hyperintensity
Explanation
Focal T2 hyperintensity in the spinal cord can indicate transient edema, inflammation, or early myelomalacia. However, when combined with T1 hypointensity, it indicates established cystic myelomalacia, necrosis, and permanent spinal cord damage. This combination serves as a strong negative predictor for neurologic recovery post-decompression.
Question 6919
Topic: Thoracolumbar Spine & Deformity
A 12-year-old gymnast presents with back pain and a grade II isthmic spondylolisthesis at L5-S1. Radiographic spinopelvic parameters are measured. Which of the following parameters is a fixed, morphological characteristic of the pelvis that strongly correlates with the magnitude of shear stress at the lumbosacral junction and the risk of slip progression?
Correct Answer & Explanation
. Pelvic incidence (PI)
Explanation
Pelvic incidence (PI) is a fixed anatomical parameter unique to each individual, defined as the angle between a line perpendicular to the sacral endplate at its midpoint and a line connecting this point to the axis of the femoral heads. PI = PT + SS. A high pelvic incidence correlates with a steeper sacral slope, leading to higher shear forces at L5-S1 and predisposing to isthmic spondylolisthesis progression.
Question 6920
Topic: 6. Spine
In an adult patient presenting with neurogenic claudication secondary to an L4-L5 degenerative spondylolisthesis, which neural element is most commonly compressed, producing radicular symptoms?
Correct Answer & Explanation
. L5 nerve root in the lateral recess
Explanation
Degenerative spondylolisthesis most commonly occurs at the L4-L5 level with an intact pars interarticularis. This condition leads to central canal and lateral recess stenosis, which compresses the traversing L5 nerve root rather than the exiting L4 nerve root.
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