Is an open splenectomy a very long procedure?

No. The operative time for an open splenectomy is between 60-90 minutes. The recovery time includes a 4-5 day hospital stay and 3-4 weeks before returning to normal activities. In contrast, a laparoscopic splenectomy may take longer but the recovery times are cut in half.
Depends on size. An open splenectomy may take about 2 hours to perform. But times will vary depending on the size of the spleen, the reason it is being removed, any prior abdominal surgery, and some risks for bleeding.