Menu

6. Spine MCQs

Practice Set 297 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 5921

Topic: 6. Spine

A 15-year-old gymnast complains of chronic low back pain, exacerbated by hyperextension activities. Physical examination reveals a palpable 'step-off' at L5-S1. Radiographs show anterior translation of L5 on S1. What is the MOST likely diagnosis?

. Lumbar disc herniation
. Facet joint arthritis
. Spinal stenosis
. Isthmic spondylolisthesis
. Degenerative spondylolisthesis

Correct Answer & Explanation

. Isthmic spondylolisthesis

Explanation

This presentation (adolescent, athlete, low back pain with hyperextension, palpable step-off, anterior translation of L5 on S1) is classic for Isthmic Spondylolisthesis, which is a forward slip of one vertebra over another due to a defect (spondylolysis) in the pars interarticularis. Degenerative spondylolisthesis typically occurs in older adults without a pars defect. Disc herniation, facet arthritis, and stenosis have different pain patterns and lack the step-off sign in adolescents.

Question 5922

Topic: 6. Spine

A 65-year-old male with a history of prostate cancer presents with new-onset severe mid-back pain that is worse at night and not relieved by rest. He reports mild leg weakness. What is the MOST likely cause of his symptoms, and what is the preferred imaging modality?

. Lumbar disc herniation; MRI
. Osteoporotic vertebral fracture; X-ray
. Spinal epidural abscess; CT scan
. Spinal cord compression from metastatic disease; urgent MRI of the spine
. Degenerative spondylolisthesis; dynamic X-rays

Correct Answer & Explanation

. Spinal cord compression from metastatic disease; urgent MRI of the spine

Explanation

A patient with a known history of prostate cancer presenting with new, severe back pain (especially worse at night and unrelieved by rest – 'red flag' symptoms for malignancy) and neurological symptoms (leg weakness) should be highly suspected of having spinal cord compression from metastatic disease. Urgent MRI of the entire spine is the preferred imaging modality to assess for spinal cord compression and delineate the extent of metastatic lesions, guiding emergent treatment. Lumbar disc herniation rarely causes such severe night pain unrelieved by rest. Epidural abscess is a possibility but less likely than metastasis with a cancer history. X-rays are insufficient to rule out cord compression.

Question 5923

Topic: 6. Spine

A 45-year-old male complains of right arm pain, numbness in his thumb and index finger, and weakness in wrist extension. Reflexes are diminished at the brachioradialis. Which cervical nerve root is MOST likely compressed?

. C4
. C5
. C6
. C7
. C8

Correct Answer & Explanation

. C6

Explanation

This constellation of symptoms (thumb and index finger numbness, wrist extensor weakness, diminished brachioradialis reflex) is classic for C6 radiculopathy. C5 involves deltoid weakness. C7 affects the middle finger, triceps, and wrist flexors. C8 affects the small finger and finger flexors. C4 involves shoulder shrug and sensation over the trapezius.

Question 5924

Topic: 6. Spine

A 70-year-old male complains of bilateral leg pain and numbness that is worse with standing and walking, but relieved by sitting or leaning forward (shopping cart sign). He has no focal motor weakness. What is the MOST likely diagnosis?

. Lumbar disc herniation
. Spinal claudication due to lumbar spinal stenosis
. Peripheral neuropathy
. Vascular claudication
. Piriformis syndrome

Correct Answer & Explanation

. Spinal claudication due to lumbar spinal stenosis

Explanation

The characteristic symptoms of bilateral leg pain and numbness, exacerbated by standing/walking and relieved by sitting or leaning forward (the 'shopping cart sign'), are classic for neurogenic claudication caused by lumbar spinal stenosis. This is due to compression of the cauda equina nerve roots in the narrowed spinal canal. Vascular claudication is also worse with activity but typically relieved by standing still, not necessarily by sitting, and is associated with diminished pulses. Lumbar disc herniation usually causes unilateral, radicular pain, not typically bilateral positional symptoms. Peripheral neuropathy and piriformis syndrome have different presentations.

Question 5925

Topic: 6. Spine

A 50-year-old male with chronic low back pain and left leg radiculopathy extending into the foot (dermatomal pattern L5) has failed 6 weeks of conservative treatment. Neurological exam reveals weakness in dorsiflexion of the ankle. What is the MOST likely cause of his symptoms?

. Lumbar facet arthropathy
. Piriformis syndrome
. Sciatic nerve entrapment
. L4-L5 disc herniation with L5 nerve root compression
. Sacroiliac joint dysfunction

Correct Answer & Explanation

. L4-L5 disc herniation with L5 nerve root compression

Explanation

Chronic low back pain with radiculopathy in an L5 dermatomal pattern (lateral leg, dorsum of foot, weakness in ankle dorsiflexion, affecting tibialis anterior) is highly suggestive of L5 nerve root compression, most commonly due to an L4-L5 disc herniation. Facet arthropathy and SI joint dysfunction typically do not cause radicular pain with motor weakness. Piriformis syndrome affects the sciatic nerve but usually presents with gluteal pain and less specific dermatomal symptoms.

Question 5926

Topic: 6. Spine

Which of the following nerves is MOST commonly injured during an anterior approach to the cervical spine (ACDF)?

. Recurrent laryngeal nerve
. Phrenic nerve
. Vagus nerve
. Hypoglossal nerve
. Spinal accessory nerve

Correct Answer & Explanation

. Recurrent laryngeal nerve

Explanation

The recurrent laryngeal nerve is the most commonly injured nerve during an anterior cervical discectomy and fusion (ACDF). It supplies the intrinsic muscles of the larynx and loops around the subclavian artery (right side) or aortic arch (left side). Its proximity to the surgical field and variable course makes it vulnerable to injury during retraction, dissection, or electrocautery, leading to dysphonia (hoarseness). The phrenic nerve, vagus nerve, hypoglossal nerve, and spinal accessory nerve are also in the vicinity but are less commonly injured.

Question 5927

Topic: 6. Spine

A 65-year-old female presents with persistent deep gluteal pain, worse with sitting and relieved by standing. Physical examination reveals tenderness over the sciatic notch and pain with resisted hip external rotation. What is the most likely diagnosis?

. Lumbar radiculopathy (L5-S1)
. Trochanteric bursitis
. Piriformis syndrome
. Sacroiliac joint dysfunction
. Hamstring tendinopathy

Correct Answer & Explanation

. Piriformis syndrome

Explanation

Piriformis syndrome is characterized by buttock pain, often radiating down the leg (pseudoradiculopathy), caused by sciatic nerve compression or irritation by the piriformis muscle. It is typically worse with prolonged sitting and activities involving hip external rotation. Tenderness over the sciatic notch and pain with resisted hip external rotation are classic findings. Lumbar radiculopathy would usually have neurological deficits more consistent with a specific nerve root. Trochanteric bursitis causes lateral hip pain. Sacroiliac joint dysfunction would involve pain with SIJ provocative tests. Hamstring tendinopathy typically involves more distal pain and tenderness along the hamstring insertion.

Question 5928

Topic: 6. Spine

Which of the following is considered a 'red flag' symptom for serious spinal pathology that warrants immediate investigation?

. Chronic low back pain lasting >6 weeks
. Pain radiating below the knee
. Morning stiffness lasting <30 minutes
. New onset bowel or bladder dysfunction
. Pain worsened by activity and relieved by rest

Correct Answer & Explanation

. New onset bowel or bladder dysfunction

Explanation

New onset bowel or bladder dysfunction (urinary retention with overflow incontinence, fecal incontinence) is a classic 'red flag' for cauda equina syndrome, a neurosurgical emergency requiring urgent investigation and potentially surgical decompression. Other red flags include progressive neurological deficit, unexplained weight loss, fever, night pain, and a history of cancer or immunosuppression. The other options describe common features of mechanical low back pain or radiculopathy, which, while needing evaluation, are not typically emergent 'red flags'.

Question 5929

Topic: 6. Spine

What is the primary indication for surgical intervention in a patient with adult degenerative lumbar scoliosis?

. Curve magnitude >30 degrees
. Persistent low back pain refractory to conservative management
. Significant leg length discrepancy
. Progressive neurological deficit (e.g., motor weakness, cauda equina)
. Cosmetic deformity

Correct Answer & Explanation

. Progressive neurological deficit (e.g., motor weakness, cauda equina)

Explanation

The primary indication for surgical intervention in adult degenerative lumbar scoliosis is progressive neurological deficit (e.g., motor weakness, radiculopathy, or cauda equina syndrome) that correlates with the deformity, or intractable pain that has failed prolonged conservative management. While curve magnitude, leg length discrepancy, and cosmetic deformity are considerations, they are typically not primary indications for surgery unless associated with significant pain or neurological compromise. Surgery for degenerative scoliosis is complex and carries significant risks, so indications are carefully considered.

Question 5930

Topic: 6. Spine

A patient undergoing knee arthroplasty receives a neuraxial anesthetic. Which of the following potential complications of neuraxial anesthesia is correctly matched with its management?

. Hypotension: Administer IV atropine
. Spinal hematoma: Urgent MRI and surgical decompression
. Postdural puncture headache: Immediate blood transfusion
. High spinal block: Trendelenburg position and aggressive fluid bolus
. Nerve injury: Prolonged physical therapy and watchful waiting

Correct Answer & Explanation

. Spinal hematoma: Urgent MRI and surgical decompression

Explanation

Spinal hematoma is a rare but devastating complication of neuraxial anesthesia, especially in patients on anticoagulants. Prompt recognition, urgent MRI for diagnosis, and emergent surgical decompression are critical to prevent permanent neurological deficits. Hypotension is managed with IV fluids and vasopressors (e.g., phenylephrine), not atropine. Postdural puncture headache is often treated with a blood patch, not transfusion. A high spinal block requires ventilatory support and hemodynamic management. Nerve injury requires thorough investigation and management, not just watchful waiting.

Question 5931

Topic: 6. Spine

A 60-year-old male with a history of intravenous drug use presents with acute onset fever, chills, and severe back pain localized to the lumbar spine. He has no neurological deficits. Labs show elevated ESR and CRP. What is the most likely diagnosis?

. Mechanical low back pain
. Herniated nucleus pulposus
. Spinal epidural abscess
. Vertebral osteomyelitis/Discitis
. Malignancy

Correct Answer & Explanation

. Vertebral osteomyelitis/Discitis

Explanation

The patient's presentation (fever, chills, severe localized back pain, IV drug use, elevated inflammatory markers) is highly suspicious for vertebral osteomyelitis and/or discitis. IV drug use is a significant risk factor for hematogenous spread of infection to the spine. While a spinal epidural abscess is also a serious possibility and often coexists, the initial infection of the vertebral body and/or disc (osteomyelitis/discitis) is the most likely primary diagnosis. Mechanical back pain and HNP would not typically present with fever and chills. Malignancy is possible but less likely with acute fever and high inflammatory markers. Urgent MRI is needed for definitive diagnosis and differentiation.

Question 5932

Topic: 6. Spine

In the context of spinal cord injury, a 'spinal cord perfusion pressure' (SCPP) can be conceptualized. While not routinely measured directly, what general principle regarding blood pressure management is aimed at optimizing SCPP in acute spinal cord injury patients?

. Maintaining a systolic blood pressure below 90 mmHg to reduce intracranial pressure.
. Permissive hypotension to prevent vasospasm.
. Maintaining a mean arterial pressure (MAP) between 85-90 mmHg.
. Aggressive diuresis to reduce spinal cord edema.
. Strict bed rest without any mobilization.

Correct Answer & Explanation

. Maintaining a mean arterial pressure (MAP) between 85-90 mmHg.

Explanation

Current guidelines for acute spinal cord injury often recommend maintaining a mean arterial pressure (MAP) between 85-90 mmHg for the first 7 days post-injury. This target aims to optimize spinal cord perfusion pressure (SCPP = MAP - intraspinal pressure) and prevent secondary ischemic injury to the compromised spinal cord. Pressures below 85 mmHg are associated with worse neurological outcomes. The other options are incorrect or detrimental in this context.

Question 5933

Topic: 6. Spine

A 60-year-old patient with osteoporosis suffers a vertebral compression fracture. While not directly measuring mmHg, effective management often involves bracing. What is the primary biomechanical principle of a thoracolumbosacral orthosis (TLSO) in relation to pressure to aid healing and pain reduction?

. To provide continuous axial compression to the fractured vertebra.
. To prevent all spinal motion at the fracture site.
. To restrict flexion and extension, thereby offloading the anterior column of the spine.
. To increase intra-abdominal pressure, thus decompressing the vertebral bodies.
. To apply heat and improve blood flow to the fractured area.

Correct Answer & Explanation

. To restrict flexion and extension, thereby offloading the anterior column of the spine.

Explanation

A TLSO (Thoracolumbosacral Orthosis) for vertebral compression fractures aims to reduce pain and promote healing by limiting spinal motion, particularly flexion. By restricting flexion, it helps to offload the anterior column of the spine, where the compression fracture has occurred, thereby reducing the compressive stress on the healing vertebral body. It does not provide continuous axial compression directly but rather stabilizes the spine and redistributes forces. While it restricts motion, complete prevention of all motion is often impractical. It can increase intra-abdominal pressure, which indirectly supports the anterior column, but the primary action is limiting flexion.

Question 5934

Topic: 6. Spine

In the surgical management of scoliosis, significant intraoperative blood loss can occur. If systemic blood pressure drops significantly, what is the primary concern for the spinal cord, particularly regarding perfusion pressure?

. Increased risk of epidural hematoma.
. Compromised spinal cord perfusion pressure (SCPP), leading to ischemic injury.
. Greater difficulty in correcting the spinal deformity.
. Reduced effectiveness of intraoperative neuromonitoring signals.
. Increased risk of infection.

Correct Answer & Explanation

. Compromised spinal cord perfusion pressure (SCPP), leading to ischemic injury.

Explanation

A significant drop in systemic blood pressure (hypotension) in the context of scoliosis surgery, especially during spinal instrumentation, is a major concern for the spinal cord. Reduced systemic blood pressure directly translates to a reduced spinal cord perfusion pressure (SCPP = MAP - intraspinal pressure). This can lead to spinal cord ischemia, potentially resulting in devastating neurological deficits. While neuromonitoring signals may be affected, and infection risk is always present, the primary, direct, and immediate threat from hypotension to the spinal cord is ischemic injury due to inadequate perfusion.

Question 5935

Topic: 6. Spine
A patient with a traumatic brain injury and associated cervical spine fracture is monitored in the ICU. To prevent secondary spinal cord injury, a target cerebral perfusion pressure (CPP) is often maintained. How is CPP defined in terms of pressure measurements?
. Cerebral Perfusion Pressure = Mean Arterial Pressure (MAP) + Intracranial Pressure (ICP).
. Cerebral Perfusion Pressure = Systolic Blood Pressure (SBP) - Diastolic Blood Pressure (DBP).
. Cerebral Perfusion Pressure = Mean Arterial Pressure (MAP) - Intracranial Pressure (ICP).
. Cerebral Perfusion Pressure = Central Venous Pressure (CVP) - Intracranial Pressure (ICP).
. Cerebral Perfusion Pressure = Cardiac Output × Systemic Vascular Resistance.

Correct Answer & Explanation

. Cerebral Perfusion Pressure = Mean Arterial Pressure (MAP) - Intracranial Pressure (ICP).

Explanation

Cerebral perfusion pressure (CPP) is defined as the difference between the mean arterial pressure (MAP) and the intracranial pressure (ICP). CPP = MAP - ICP. This formula reflects the driving pressure gradient that pushes blood through the cerebral vasculature. Maintaining an adequate CPP is crucial for ensuring sufficient blood flow and oxygen delivery to the brain, especially in patients with TBI, and indirectly in those with high cervical spine injury where neurological status is critical.

Question 5936

Topic: 6. Spine

When positioning a patient for prone spine surgery, what is a critical consideration related to pressure on the abdomen?

. Allowing the abdomen to hang freely to reduce intra-abdominal pressure and venous pressure.
. Applying firm abdominal compression to reduce blood loss.
. Elevating the chest and hips only, ensuring direct pressure on the abdomen.
. Using a large abdominal binder to support the internal organs.
. Placing the patient in a Trendelenburg position.

Correct Answer & Explanation

. Allowing the abdomen to hang freely to reduce intra-abdominal pressure and venous pressure.

Explanation

When positioning a patient for prone spine surgery, it is crucial to allow the abdomen to hang freely. This prevents compression of the abdomen, which would otherwise increase intra-abdominal pressure. Elevated intra-abdominal pressure can impede venous return from the lower extremities and epidural venous plexus, leading to increased epidural venous bleeding and congestion, making the surgical field wetter and potentially increasing blood loss. Therefore, devices like chest rolls or specific surgical frames are used to support the patient on the chest and pelvis, leaving the abdomen suspended.

Question 5937

Topic: 6. Spine

A 50-year-old male undergoing anterior cervical discectomy and fusion experiences a sudden drop in blood pressure to 75/40 mmHg. Heart rate is 90 bpm. Initial fluid bolus of 500 mL crystalloid has no effect. The surgical field is dry. What is the most appropriate next step given the likely mechanism?

. Administer IV Epinephrine
. Initiate IV Phenylephrine infusion
. Check for occult blood loss in the posterior surgical field
. Consider vasopressin administration
. Increase crystalloid infusion to 200 mL/hr

Correct Answer & Explanation

. Initiate IV Phenylephrine infusion

Explanation

During anterior cervical spine surgery, manipulation of the carotid sheath or vagal nerve can cause significant bradycardia and hypotension due to increased parasympathetic tone or sympathetic blockade. Also, blood pooling in the lower extremities from positioning can cause venous pooling. If the surgical field is dry, significant blood loss is unlikely. A vasopressor like Phenylephrine (a pure alpha-agonist) is the most appropriate initial agent to rapidly increase systemic vascular resistance and blood pressure, especially if a spinal or regional sympathetic blockade component is at play, or if there's relative hypovolemia despite fluid bolus. Epinephrine is typically reserved for profound shock or cardiac arrest. Vasopressin is an alternative but usually not first-line. Checking for occult blood loss is important but less likely given the 'dry field' statement. Increasing crystalloid infusion alone may not be sufficient or rapid enough.

Question 5938

Topic: 6. Spine

A 62-year-old female undergoes total shoulder arthroplasty in the beach chair position. Her blood pressure is maintained at 90/60 mmHg (mean arterial pressure 70 mmHg) throughout the case. What is the most significant potential neurological complication associated with this blood pressure management in this position?

. Posterior ischemic optic neuropathy
. Cerebral hyperperfusion syndrome
. Spinal cord ischemia
. Stroke from hypoperfusion
. Delirium

Correct Answer & Explanation

. Stroke from hypoperfusion

Explanation

The beach chair position significantly increases the height difference between the heart and the brain. While a cuff BP of 90/60 mmHg (MAP 70 mmHg) might seem acceptable at heart level, the actual cerebral perfusion pressure can be significantly lower due to the hydrostatic gradient (approximately 0.77 mmHg reduction per centimeter of height above the heart). This puts the brain at risk for hypoperfusion, especially if autoregulation is impaired (e.g., in hypertensive patients). Therefore, stroke from hypoperfusion is a major concern. Posterior ischemic optic neuropathy is primarily associated with prolonged prone positioning and profound hypotension. Cerebral hyperperfusion syndrome is usually related to carotid endarterectomy. Spinal cord ischemia is a risk in prone spinal surgery. Delirium is a general post-operative complication and not specific to this BP scenario.

Question 5939

Topic: 6. Spine

A 75-year-old male with pre-existing hypertension and renal insufficiency (Cr 2.0 mg/dL) undergoes a lengthy lumbar spinal fusion. He receives 6 liters of 0.9% Normal Saline intraoperatively. On post-operative day 1, he develops crackles on lung auscultation and an arterial blood gas shows pH 7.25, PCO2 35 mmHg, HCO3 15 mEq/L. What is the most likely acid-base disturbance?

. Metabolic alkalosis
. Respiratory acidosis
. Hyperchloremic metabolic acidosis
. Lactic acidosis
. Respiratory alkalosis

Correct Answer & Explanation

. Hyperchloremic metabolic acidosis

Explanation

The administration of large volumes of 0.9% Normal Saline, which has a high chloride content (154 mEq/L) compared to plasma (approximately 100 mEq/L), can lead to a hyperchloremic metabolic acidosis, especially in patients with impaired renal function who cannot excrete the excess chloride. The ABG findings (pH 7.25, HCO3 15 mEq/L, normal PCO2 for compensation) confirm a metabolic acidosis. Given the context, hyperchloremic metabolic acidosis is the most likely specific cause, distinguishable from lactic acidosis which would typically be associated with hypoperfusion and an elevated anion gap. This patient is also fluid overloaded (crackles), a common complication of excessive saline.

Question 5940

Topic: 6. Spine

A 70-year-old male undergoes a major spine surgery. Over the 8-hour procedure, he receives 8 liters of intravenous fluids. Post-operatively, his urine output is 20 mL/hr, and his serum creatinine has risen from 1.0 mg/dL to 2.5 mg/dL. His blood pressure is 100/60 mmHg. What is the most likely diagnosis?

. Pre-renal acute kidney injury
. Acute tubular necrosis (ATN)
. Post-renal obstruction
. Contrast-induced nephropathy
. Chronic kidney disease exacerbation

Correct Answer & Explanation

. Acute tubular necrosis (ATN)

Explanation

Acute tubular necrosis (ATN) is a common cause of acute kidney injury (AKI) in the surgical setting, especially after long surgeries with significant fluid shifts, hypotension, or nephrotoxic insults. The massive crystalloid infusion without adequate urine output, coupled with a significant rise in creatinine, suggests intrinsic renal damage. While pre-renal AKI (due to hypoperfusion) can lead to ATN if prolonged, the massive fluid administration makes 'pre-renal' less likely as the primary, immediate diagnosis given the volume. Post-renal obstruction would be indicated by imaging and often anuria. Contrast-induced nephropathy is unlikely without contrast exposure. Chronic kidney disease exacerbation would be a slower progression. The significant fluid intake combined with oliguria and worsening creatinine points to ATN.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page