Review Question - QID 211487

A 70-year-old male is treated with a C2-4 posterior decompression and instrumented fusion for worsening myelopathic symptoms. He presents for his two-week follow-up appointment is now complaining of bilateral arm weakness. He denies any new onset of pain. On examination, there is 3/5 deltoid and 4/5 biceps motor strength with 5/5 triceps, flexor digitorum profundus, extensor carpi radialis longus, and interossei motor strength. What risk factor predisposes to this condition?