A person can donate a portion of their liver only once in their lifetime. Living liver donation is a major surgical procedure where a healthy segment of the donor’s liver is removed and transplanted into a recipient. This is possible because of the liver’s unique capacity to regrow, but medical and ethical guidelines strictly limit the donor to a single procedure. The primary constraint in all organ donation is the absolute commitment to donor safety, which prohibits the significant risks associated with a second operation.
The Unique Regenerative Power of the Liver
The ability to perform a living liver transplant relies on the liver’s remarkable capacity to regenerate itself, a feature that no other solid human organ possesses. This process involves an increase in the size of the remaining liver tissue, not a perfect recreation of the original organ. When a portion is surgically removed, the remaining cells are stimulated to divide, rapidly increasing the organ’s overall mass.
Regrowth occurs through two distinct biological processes: cellular enlargement (hypertrophy) and cell division (hyperplasia). This results in a return to nearly the liver’s pre-donation volume and functional capacity for the donor. For most donors, this rapid return in size takes place over a period of weeks to a few months.
The donated segment in the recipient also undergoes enlargement and cell division, growing to a size appropriate for the recipient’s body. Within approximately two to three months, both the donor’s remaining liver and the transplanted segment function as full, healthy organs. This biological mechanism is the foundation that makes living liver donation successful.
The Scope of a Single Living Donation
A single living donation is a major operation where surgeons remove a substantial portion of the liver to ensure the recipient receives adequate functional tissue. For adult-to-adult transplants, the right lobe is often removed, constituting 40 to 60 percent of the donor’s total liver volume. The segment size is precisely calculated to leave the donor with a safe, sufficient residual liver volume.
The remaining liver must contain intact drainage systems, including the necessary blood vessels and bile ducts, to function correctly. Although tissue volume regenerates, the anatomical structure is permanently altered by the surgery, including the formation of scar tissue at the resection site. The extensive surgery requires a significant recovery period, typically two to three months before returning to normal activities, and a full year for complete physical recovery.
The procedure involves a complex reconstruction of the organ’s vascular and biliary plumbing. For instance, the main bile duct branches are divided, and one of the primary ducts is permanently redirected to the transplanted segment. This structural change means that while the donor’s liver is functionally recovered, it is no longer in its original anatomical configuration.
Safety Protocols and the Limit on Repeat Donations
Medical consensus and all major national organ donation policies strictly prohibit an individual from donating a segment of their liver more than once. Organizations like the Organ Procurement and Transplantation Network (OPTN) and the United Network for Organ Sharing (UNOS) enforce this limitation in the United States. The primary reason for this universal restriction is the non-negotiable principle of donor safety.
A second major abdominal surgery introduces a significantly higher risk of complications due to scar tissue and adhesions from the initial operation. Navigating this altered anatomy makes the dissection process longer and more hazardous, increasing the risk of bleeding, bile duct injury, and other life-threatening events. The cumulative surgical trauma is considered medically unacceptable.
Even though liver volume returns, the structural changes from the first donation preclude a second safe procedure. The critical vascular and biliary structures cut and re-connected during the first surgery are permanently rearranged. Removing a second segment would necessitate dividing the remaining single set of primary vessels and ducts. This would leave the donor with an insufficient functional reserve and an extremely high risk of liver failure.
The ethical framework of living donation requires the procedure to present minimal long-term risk to the donor. Since a second surgery would violate this principle by introducing unacceptably high and potentially lethal risks, the standard of care restricts individuals to one lifetime donation. This policy ensures the focus remains on the donor’s long-term health and well-being.