Screening

• The National Marrow Donor Program (NMDP) screens all potential donors to make sure they are healthy and should have no problems with the procedure.
  
  

Procedure

• During bone marrow donation, the patient lies on his stomach and a doctor inserts a hollow needle into the back of the pelvic bone. A syringe attached to the needle is then used to remove the marrow.
  
  

Marrow Regeneration

• Five percent or less of the donor's marrow is removed. After donation, the donor's body replaces the marrow within four to six weeks, according to the NMDP.
  
  

Anesthesia

• The procedure is usually performed with the donor under general anesthesia, or sometimes regional anesthesia. The donor does not feel pain during the process.
  
  

Side Effects

• Donation removal is typically an outpatient procedure. Most donors feel pain or pressure in their lower back afterward, as well as stiffness when walking and fatigue. It may take a few weeks for these effects to completely disappear.
  
  

Risks

• In a study cited by the Cancer Consultants website, about 1 percent of over 9,000 bone marrow harvests led to a serious negative event. These included excessive pain, anesthesia reactions, delayed return to normal activities and injury to tissue, bone or nerve. A total of 67 donors had problems lasting months or years.