to ashmic if the string is visible they clamp the string and slowly pull it back out through the cervix think they also use a local on the cervix to minimise discomfort but if there is no string present they will do an ultrasound to make sure mirena is still in the uterus and a laperoscopy procedure would be booked which is a day procedure and the mirena removed that way which is the way im waiting to get it done but as Des said if they are able to do it the usual way by what i have been told it is very easy and slight discomfort nothing much good luck with it all
i think they just pull it out it is very easy and painless