It is doubtful that the older ones will send out new growth, but not
impossible. If you can get them to bloom, then you must already have
some pretty good care info- good for you! If it's unpotted, don't pot
it up until the new roots are 1.5-2 inches long and leaves are
unfurling. You could rot out the new growth by giving it too much water
too early. If it is potted/outside naturally, then just let it go. Once
in a growth phase, water and feed it heavily, and give it plenty of
light.

There are some pictures and other info here about over wintering and
breaking dormancy for ctsms, cycs, and their relatives.
http://forums2.gardenweb.com/forums/...502631537.html