Hi,
Mostly mammary duct ecatsia heals on its own - just avoid smoking, try warm compressus keep the area clean, wear lose clothes and take Vitamin A supplements. If there is superadded infection or other symptoms you might need a course of antibiotics and painkillers. In a few cases your surgeon might think it appropriate to send the nipple discharge, if there is any, for examination. Only in rare cases, if the antibiotics and the above measure dont help then a surgery is done to remove the duct. Discuss all this in detail with your surgeon and clear any doubts. Goodluck.
I had a cyst in my milk duct. I had the milk duct removed b/c I had previously had breast cancer. Wanted to be sure it wasn't cancer even though the ultrasound showed it was probably a cyst. But then again, I had a discharge, too, unlike your wife. Insurance paid for it b/c of my breast cancer history. Your wife could look into that. Surgery wasn't so bad. Went back to work two days later.