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The JBJS Quiz of the Month is a collection of 10 relevant questions from each orthopaedic subspecialty. The questions are drawn from JBJS Clinical Classroom, which houses over 4,500 questions and 3,100 learning resources. Take the Quiz to see how you score against your peers!

NOTE: This quiz does not earn users CME credits. The questions must be answered within Clinical Classroom to earn CME credits.

A 54-year-old male patient presents to the emergency department with non-radiating thoracic back pain. He has an intact motor, sensory, and reflex examination of the bilateral upper and lower extremities. The patient has a history of hepatitis C, a 30-pack per year history of smoking cigarettes, and chronic cough for the last 3 months. His white blood-cell count, erythrocyte sedimentation rate, and C-reactive protein level are slightly elevated. Which of the following best describes the appropriate imaging modality and findings to diagnose spinal discitis/osteomyelitis?
    • Magnetic resonance imaging is the best choice, and active infection is marked by an increase in T2 signal in disc space and surrounding bone edema.
      • Magnetic resonance imaging is the modality of choice, and active infection is marked by an increase in T2 signal in disc space and surrounding bone edema.

 

    • Magnetic resonance imaging is the best choice and can distinguish active infection from a malignancy because malignancies are centered in the disc space.
      • Classically, malignancy avoids the disc space, while infection centers on it. The metastases migrate to the spine hematogenously. The disc is avascular, so tumor cells do not locate there. Infection typically develops first as an osteomyelitis when bacteria extravasate from end arterioles. Then it expands into the disc, which has no innate immunity, resulting in spondylodiscitis.

 

    • Radiographs are best at detecting early active spinal bone or disc infection.
      • Magnetic resonance imaging is the modality of choice, and active infection is marked by an increase in T2 signal in disc space and surrounding bone edema. Radiographs are good to assess stability and deformity, but it takes weeks for the classic signs of infection to develop (disc height narrowing, endplate irregularity, and vertebral radiolucency).

 

    • A computed tomography (CT) scan showing endplate erosion is pathognomonic for spinal discitis/osteomyelitis.
      • Magnetic resonance imaging is the modality of choice, and active infection is marked by an increase in T2 signal in disc space and surrounding bone edema. CT is better than radiiographs, but neither are as diagnostic as magnetic resonance imaging (MRI).

 

 

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