Hi Kathleen
If Olivia is on regular transfusion I guess she should have a normal spleen as she keeping a high level of hb, never the less 3 cm is not something to worry about.
I remember from the conference that I attended that the spleen is removed when
1- it is over sized and it threatening the patient's life by rapture
2-when it is destroying the red blood cells causing continous drop in hb and therefore decreasing the gaps between transfusions and this will be accompanied with slow growth of the child because spleen enlargement Consumes the body's energy and therefore decreases the rate of growth.
Manal