In about two percent of cases, bone marrow is collected from the pelvic bone under a full anaesthetic using a thin, sterile needle. As a rule, two small incisions at the back of the pelvic bone are all that is required. The riskiest part of the procedure is essentially the anaesthetic. About five percent of the bone marrow is removed, which the body fully regenerates. Some donors experience localised pain from the incision, which often feels like bruising. The donor spends three days in hospital. On the first day you check in, on the second you have the procedure, and on the third you are discharged.