Complex sentence: In very severe HbCS (usually HbH HCS), a removal of the spleen (splenectomy) is associated with reduced transfusions and improvement in hemoglobin levels.
Split into simpler sentences: In very severe HbCS (usually HbH HCS), transfusions may be required to treat bouts of anemia. In these patients, removal of the spleen (splenectomy) is associated with reduced transfusions and improvement in hemoglobin levels.