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1. General Principles & Basic Science MCQs

Practice Set 439 of 789

This practice set contains high-yield board review questions covering key concepts in 1. General Principles & Basic Science. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 8761

Topic: Surgical Anatomy & Approaches

A 35-year-old man sustains an acetabular fracture as seen in the representative imaging

. CT reveals a fracture involving the anterior column and posterior hemitransverse with the "gull sign" present on the anteroposterior view. Which surgical approach is most appropriate?

. Kocher-Langenbeck
. Ilioinguinal or Modified Stoppa
. Extended iliofemoral
. Smith-Petersen
. Posterior approach with trochanteric osteotomy

Correct Answer & Explanation

. Ilioinguinal or Modified Stoppa

Explanation

An anterior column and posterior hemitransverse fracture is best approached anteriorly (Ilioinguinal or modified Stoppa) to directly reduce the anterior column. The "gull sign" indicates superomedial dome impaction, which must be addressed through an anterior approach.

Question 8762

Topic: Biology, Genetics & Bone Healing

A 72-year-old woman on long-term alendronate presents with lateral thigh pain. Radiographs reveal focal lateral cortical thickening and a transverse radiolucent line in the subtrochanteric femur. What is the most appropriate management?

. Discontinue alendronate and observe clinically
. Switch to teriparatide and restrict weight-bearing
. Prophylactic intramedullary nailing
. Open reduction and plate fixation
. Core decompression

Correct Answer & Explanation

. Prophylactic intramedullary nailing

Explanation

This patient has an impending atypical femur fracture (AFF) associated with prolonged bisphosphonate use. Given the high risk of completion and significant morbidity, prophylactic cephalomedullary or intramedullary nailing is the treatment of choice.

Question 8763

Topic: 1. General Principles & Basic Science

A 24-year-old male lacerates his index finger flexor digitorum profundus (FDP) and superficialis (FDS) in Zone II. What is the optimal timing and method for repair to ensure the best functional outcome?

. Delayed repair at 3 weeks using a 2-strand technique
. Primary repair within days using a multi-strand core suture with epitendinous repair
. Tendon grafting via staged reconstruction
. FDP repair only with intentional excision of the FDS
. Immobilization for 4 weeks followed by late repair

Correct Answer & Explanation

. Primary repair within days using a multi-strand core suture with epitendinous repair

Explanation

Zone II flexor tendon lacerations are optimally managed with early primary repair (within days) utilizing a robust multi-strand (4 or 6) core suture plus an epitendinous suture. This provides sufficient tensile strength to allow early active rehabilitation protocols, preventing adhesions.

Question 8764

Topic: 1. General Principles & Basic Science

A 40-year-old man sustains a bicondylar tibial plateau fracture. Computed tomography imaging reveals a large, proximally displaced posteromedial coronal fragment. To optimally reduce and buttress this specific fragment, what surgical approach is most appropriate?

. Standard anterolateral approach
. Direct medial approach
. Posteromedial approach utilizing the interval between the medial head of the gastrocnemius and the pes anserinus
. Posterolateral approach
. Anteromedial approach

Correct Answer & Explanation

. Posteromedial approach utilizing the interval between the medial head of the gastrocnemius and the pes anserinus

Explanation

Posteromedial tibial plateau fragments require a posterior buttress plate for mechanical stability. The optimal access is via a posteromedial approach, working in the interval between the medial gastrocnemius and pes tendons.

Question 8765

Topic: Surgical Anatomy & Approaches

A 25-year-old male sustains a closed transverse midshaft humerus fracture. He is neurologically intact on initial presentation and placed in a coaptation splint. Two weeks later at follow-up, he exhibits a complete radial nerve palsy. What is the most appropriate management?

. Immediate surgical exploration and nerve repair
. Immediate EMG/NCS
. Observation and continued functional bracing
. MRI of the humerus
. Conversion to an external fixator

Correct Answer & Explanation

. Observation and continued functional bracing

Explanation

Secondary radial nerve palsies developing after closed reduction or bracing of a closed humeral shaft fracture are typically neuropraxias. They have a high rate of spontaneous recovery, making observation the most appropriate initial management.

Question 8766

Topic: Biology, Genetics & Bone Healing

A 65-year-old woman on alendronate for 12 years presents with an incomplete, transverse fracture through the lateral cortex of the subtrochanteric femur. She reports progressive thigh pain over the last 3 months. What is the most appropriate management for this symptomatic impending atypical femur fracture?

. Discontinue alendronate and observe with protected weight-bearing
. Immediate core decompression of the femoral head
. Prophylactic cephalomedullary nailing of the affected femur
. Open reduction and internal fixation with a dynamic hip screw
. Switch to denosumab and allow weight-bearing as tolerated

Correct Answer & Explanation

. Prophylactic cephalomedullary nailing of the affected femur

Explanation

Symptomatic incomplete atypical femoral fractures associated with prolonged bisphosphonate use are at high risk of completing. Prophylactic intramedullary nailing is indicated to relieve pain and prevent catastrophic displacement.

Question 8767

Topic: Surgical Anatomy & Approaches

A 32-year-old woman is involved in a high-speed motor vehicle collision and suffers a posterior hip dislocation. Closed reduction in the emergency department is unsuccessful. A CT scan reveals an intra-articular osteochondral fragment physically blocking the reduction. Which surgical approach is most appropriate to extract the fragment and reduce the hip?

. Smith-Petersen (anterior) approach
. Kocher-Langenbeck (posterior) approach
. Watson-Jones (anterolateral) approach
. Ilioinguinal approach
. Direct superior approach

Correct Answer & Explanation

. Kocher-Langenbeck (posterior) approach

Explanation

For an irreducible posterior hip dislocation with posterior wall/acetabular fragments blocking reduction, the Kocher-Langenbeck (posterior) approach allows direct visualization, extraction of incarcerated fragments, and repair of the posterior column/wall.

Question 8768

Topic: Infection, Pharmacology & VTE
A 40-year-old farmer sustains a Grade IIIb open tibia fracture heavily contaminated with soil and manure. Based on current trauma guidelines, which of the following prophylactic antibiotic regimens is most appropriate upon presentation?
. Cefazolin monotherapy for 24 hours
. Ceftriaxone and vancomycin for 7 days
. Cefazolin and clindamycin for 48 hours
. Ceftriaxone, vancomycin, and high-dose penicillin for 72 hours
. Ciprofloxacin monotherapy for 5 days

Correct Answer & Explanation

. Ceftriaxone, vancomycin, and high-dose penicillin for 72 hours

Explanation

High-energy Grade III open fractures require broad-spectrum coverage, typically a cephalosporin and vancomycin. When there is gross soil or farm contamination, adding high-dose penicillin is strongly recommended to cover for Clostridium species.

Question 8769

Topic: 1. General Principles & Basic Science

A 65-year-old man with underlying cervical spondylosis falls forward and strikes his chin, sustaining a hyperextension injury. He immediately develops profound weakness in his upper extremities with relatively preserved motor function in his lower extremities. What is the most likely diagnosis?

. Anterior cord syndrome
. Brown-Sequard syndrome
. Central cord syndrome
. Posterior cord syndrome
. Conus medullaris syndrome

Correct Answer & Explanation

. Central cord syndrome

Explanation

Central cord syndrome classically occurs in older patients with pre-existing cervical spondylosis following a hyperextension injury. It disproportionately affects the medially located cervical motor tracts, causing upper extremity weakness greater than lower extremity weakness.

Question 8770

Topic: 1. General Principles & Basic Science
A 70-year-old man with a history of cervical spondylosis falls forward, striking his chin. He presents with profound motor weakness in his upper extremities but is able to move his lower extremities against gravity. He has variable sensory loss and urinary retention. Which of the following is the most likely diagnosis?
. Anterior cord syndrome
. Brown-Séquard syndrome
. Central cord syndrome
. Posterior cord syndrome
. Conus medullaris syndrome

Correct Answer & Explanation

. Central cord syndrome

Explanation

Central cord syndrome typically occurs in elderly patients with pre-existing cervical spondylosis after a hyperextension injury. It presents with disproportionately greater motor impairment in the upper extremities compared to the lower extremities.

Question 8771

Topic: Physiology & Rehabilitation
A patient suffers a penetrating knife injury to the right side of the spinal cord at the T10 level. Which of the following neurological deficits is expected below the level of the injury?
. Loss of ipsilateral motor function and contralateral pain and temperature sensation
. Loss of contralateral motor function and ipsilateral pain and temperature sensation
. Bilateral loss of motor function and pain sensation with preserved proprioception
. Bilateral loss of proprioception and vibration sensation with preserved motor function
. Loss of ipsilateral pain and temperature sensation and contralateral motor function

Correct Answer & Explanation

. Loss of ipsilateral motor function and contralateral pain and temperature sensation

Explanation

This describes Brown-Séquard syndrome resulting from spinal cord hemisection. It classically presents with ipsilateral loss of motor function and proprioception, and contralateral loss of pain and temperature sensation.

Question 8772

Topic: Infection, Pharmacology & VTE

A 60-year-old diabetic male undergoes a lumbar microdiscectomy. Three weeks later, he presents with severe, unremitting back pain and elevated inflammatory markers. An MRI shows fluid in the disc space with endplate enhancement. What is the most likely causative organism?

. Pseudomonas aeruginosa
. Escherichia coli
. Staphylococcus aureus
. Streptococcus epidermidis
. Mycobacterium tuberculosis

Correct Answer & Explanation

. Staphylococcus aureus

Explanation

Staphylococcus aureus is the most common causative organism for both spontaneous and postoperative pyogenic discitis and vertebral osteomyelitis.

Question 8773

Topic: Biology, Genetics & Bone Healing

A 78-year-old woman with a history of severe osteoporosis presents with acute-onset, severe mid-back pain after coughing. MRI confirms an acute T11 compression fracture without posterior wall involvement or neurologic deficit. She has failed 6 weeks of aggressive conservative management including bracing and analgesics. What is the most appropriate next step?

. Posterior T10-T12 spinal fusion
. Anterior corpectomy and strut grafting
. Kyphoplasty or vertebroplasty
. Continuation of conservative management for 6 more months
. Lumbar epidural steroid injection

Correct Answer & Explanation

. Kyphoplasty or vertebroplasty

Explanation

Vertebral augmentation techniques like kyphoplasty or vertebroplasty are indicated for osteoporotic compression fractures causing debilitating pain that persists despite 4 to 6 weeks of adequate nonoperative management.

Question 8774

Topic: 1. General Principles & Basic Science

A 48-year-old woman undergoes a straightforward L4-L5 microdiscectomy. During the procedure, a small incidental durotomy is primarily repaired with a watertight suture. On postoperative day 1, she complains of a severe headache that worsens when she sits up and resolves when she lies flat. What is the best initial management?

. Immediate return to the operating room for repair revision
. Placement of a subarachnoid lumbar drain
. Bed rest, aggressive intravenous hydration, and caffeine
. Epidural blood patch
. Head CT scan to rule out pneumocephalus

Correct Answer & Explanation

. Bed rest, aggressive intravenous hydration, and caffeine

Explanation

A positional headache after an incidental durotomy indicates a persistent CSF leak. The initial management for a recognized and primarily repaired tear includes bed rest, hydration, and caffeine before considering invasive measures like a blood patch or surgical revision.

Question 8775

Topic: 1. General Principles & Basic Science

A 50-year-old woman undergoes an uncomplicated L4-L5 microdiscectomy. On postoperative day 2, she complains of severe positional headaches that worsen when sitting upright and improve upon lying flat. Which of the following is the most appropriate initial management?

. Immediate return to the operating room for dural repair
. Lumbar subarachnoid drain placement
. Bed rest, oral hydration, and caffeine
. Epidural blood patch
. High-dose corticosteroids

Correct Answer & Explanation

. Bed rest, oral hydration, and caffeine

Explanation

Post-dural puncture headaches caused by an occult incidental durotomy are initially managed conservatively with bed rest, hydration, and caffeine. If conservative measures fail after several days, an epidural blood patch or surgical re-exploration may be considered.

Question 8776

Topic: 1. General Principles & Basic Science

A 45-year-old man undergoes an anterior lumbar interbody fusion (ALIF) at L5-S1. Postoperatively, he complains of cloudy urine and a lack of seminal emission during orgasm. Injury to which of the following structures is the most likely cause?

. Pudendal nerve
. Superior hypogastric plexus
. Inferior hypogastric plexus
. Parasympathetic pelvic splanchnic nerves
. Genitofemoral nerve

Correct Answer & Explanation

. Superior hypogastric plexus

Explanation

Retrograde ejaculation following an L5-S1 ALIF is caused by iatrogenic injury to the superior hypogastric plexus, which provides sympathetic innervation to the internal urethral sphincter. Utilizing blunt dissection and avoiding monopolar electrocautery over the L5-S1 disc space minimizes this risk.

Question 8777

Topic: 1. General Principles & Basic Science

A 15-year-old male gymnast has severe lower back pain exacerbated by extension. Radiographs and MRI confirm a bilateral L5 spondylolysis without listhesis. He has failed 6 months of bracing and physical therapy. A diagnostic injection of the pars defect provides complete temporary relief. What is the most appropriate surgical treatment?

. L5-S1 anterior lumbar interbody fusion (ALIF)
. L5-S1 posterolateral instrumented fusion
. Direct pars repair
. L5 laminectomy
. L4-S1 posterior instrumented fusion

Correct Answer & Explanation

. Direct pars repair

Explanation

In a young, highly active patient with symptomatic spondylolysis without listhesis who fails prolonged nonoperative management, direct pars repair is the procedure of choice. This technique stabilizes the defect while preserving normal lumbar motion segments.

Question 8778

Topic: 1. General Principles & Basic Science
During the application of a halo vest in an adult, the anterior pins are placed 1 cm superior to the lateral one-third of the eyebrow. This specific placement is designed to minimize the risk of injury to branches of which cranial nerve?
. Facial nerve (CN VII)
. Optic nerve (CN II)
. Oculomotor nerve (CN III)
. Trigeminal nerve (CN V)
. Trochlear nerve (CN IV)

Correct Answer & Explanation

. Trigeminal nerve (CN V)

Explanation

Anterior halo pins are placed laterally to avoid injuring the supraorbital and supratrochlear nerves. These nerves are terminal branches of the ophthalmic division (V1) of the trigeminal nerve (CN V).

Question 8779

Topic: 1. General Principles & Basic Science

During a posterior lumbar decompression and interbody fusion (PLIF) at L4-L5, the surgeon inadvertently tears the dura, resulting in a cerebrospinal fluid leak. A primary, watertight dural repair is successfully achieved. What is the standard post-operative management to minimize the risk of a persistent CSF fistula?

. Immediate placement of a lumbar subarachnoid drain
. Flat bed rest for 24 to 48 hours
. Early mobilization with a rigid TLSO brace
. Re-exploration and placement of a fascial graft at 24 hours
. Intravenous broad-spectrum antibiotics for 14 days

Correct Answer & Explanation

. Flat bed rest for 24 to 48 hours

Explanation

The standard of care following an intraoperative primary repair of an incidental durotomy is a period of flat bed rest, typically for 24 to 48 hours. This reduces hydrostatic pressure on the repair site and allows initial tissue sealing, minimizing the risk of a persistent leak or pseudomeningocele.

Question 8780

Topic: 1. General Principles & Basic Science

During the posterior surgical exposure of the C1 posterior arch, the surgeon must exercise extreme caution to avoid catastrophic vascular injury. What is the maximum safe distance for lateral subperiosteal dissection from the posterior midline of C1?

. 5 mm
. 10 mm
. 15 mm
. 25 mm
. 30 mm

Correct Answer & Explanation

. 15 mm

Explanation

The vertebral artery rests in the sulcus arteriosus on the superior surface of the C1 posterior arch. To avoid iatrogenic injury to the vertebral artery, lateral dissection along the posterior arch should strictly not exceed 15 mm from the midline.

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