What syndrome is indicated by bilateral paralysis of the lower extremities with intact light touch and vibration sensation, following a recent thoracic aortic aneurysm repair?

The scenario described is indicative of anterior cord syndrome. This condition results from damage to the anterior two-thirds of the spinal cord, which affects the function of the corticospinal and spinothalamic tracts. In anterior cord syndrome, the hallmark symptoms include bilateral paralysis of the lower extremities due to the disruption of motor pathways, along with loss of pain and temperature sensations, while light touch and vibration sensations remain intact because the dorsal columns are spared.

In the context of a recent thoracic aortic aneurysm repair, it is not uncommon for patients to experience such an injury due to factors like hypotension or direct mechanical injury to the spinal cord during surgical manipulation or vascular compromise. The preservation of light touch and vibration sensation indicates that the dorsal columns, which mediate these sensations, are unaffected.

This clinical picture aligns exactly with anterior cord syndrome, reinforcing that the loss of motor function occurs along with selective loss of specific sensory modalities. Thus, the diagnosis is consistent with the symptoms presented and the surgical history of the patient.