Best wishes on your procedure!!
I have had both a modified Whipple and a distal pancreatectomy and splenectomy. I had a drain after both surgeries. I was fortunate that the drains were able to be removed prior to my discharge from the hospital. I kept the drain after the Whipple for around 11 days and around 5 days for the distal pancreatectomy and splenectomy. Since you asked specifically about the distal pancreatectomy and splenectomy - I did not have any complications from the procedure and tolerated it well. My surgery was done at Mayo.
Take care!