Anterior spinal artery syndrome and its natural history.

The anterior spinal artery syndrome in three patients is described and from the literature 60 additional patients were collected. Motor recovery in the following groups of patients was noted: (1) Partial loss of motor function and pain sensation--70.4 per cent (19/27); (2) Complete motor loss but partial loss of pain--83.3 per cent (5/6); (3) Paresis but pain sensation absent--66.7 per cent (6/9); and (4) Absent motor function and pain--38.9 per cent (7/18). Motor recovery was also found to vary according to aetiology: (A) Unknown cause--92.9 per cent (13/14); (B) Post-infection or vaccination--88.9 per cent (8/9); (C) Anterior spinal artery occlusion--33.3 per cent (3/9); (D) Spinal cord angioma--20 per cent (2/10); and (E) Aortic lesion--20 per cent (1/5). Patients with sparing of motor function or pain sensation below the lesion do better than those without both functions. Neurological return also varies with the aetiology of the syndrome.