We studied long-term outcome (range, 28-89 months; mean, 56 months) after m
ultiple subpial transections (MST) for medically refractory epilepsy. Forty
-three (79.6%) of 54 patients had a consistent significant reduction in sei
zure frequency, and 27 (50%) of the 54 were either entirely seizure free or
virtually so. However, 10 (18.5%) patients sustained an increase in seizur
e frequency several years after surgery, after showing initial postoperativ
e improvement. This suggests that late seizure recurrence is a more importa
nt problem in cases in which MST has been performed than for pure resection
s.