Final answer:
Previously, bone marrow sampling and transplants were invasive and painful procedures. However, advancements in technology have allowed for the isolation of stem cells from a patient's blood, eliminating the need for direct sampling of bone marrow.
Step-by-step explanation:
Previously, bone marrow sampling and transplants required the insertion of a large-bore needle into the pelvic bones, which was a painful procedure. However, now direct sampling of bone marrow can often be avoided. Stem cells can be isolated from a patient's blood, grown in culture, and analyzed or frozen for later use. This has made the process less invasive and more efficient.