The onset time of sensory and motor sciatic nerve block was 4 minutes ( 2-9 minutes ) in group I and 6 minutes ( 4-10 minutes ) in group II ( P = 0.41 ; WMWodds 1.21 [ 0.77-1 .95 ] ) , while the duration of sensory block was 235 minutes ( 203-250 minutes ) in group I , and 240 minutes ( 218-247 minutes ) in group II respectively ( P = 0.51 ; WMWodds 1.20 [ 0.69-2 .16 ] ) .