A plan intended to correct regional inequities among liver transplant recipients is on hold after a lawsuit to block its implementation was filed by transplant centers in the South and Midwest.

The United Network for Organ Sharing (UNOS) has worked to create a new way of distributing organs since 2012. The plan calls for the most critically ill patients within a set geographic parameter to receive organs first. For example, if a liver became available in Nashville, the sickest patient within a 500 nautical-mile radius would receive it.

For years, organ distribution has been carried out within 11 geographic areas. Each area maintained its own waiting list and when a liver became available, the sickest patient within the region received it.

UNOS has worked for years to revise the organ distribution system. Waiting lists on the coasts and in urban centers have always been longer than those in rural areas. Consider that the waiting list at Vanderbilt Medical Center in Nashville has about 171 patients, while the one at the University of California's San Francisco Medical Center has more than 750.

Yet each center performs roughly 140 transplants each year. Plus, organ donation rates in the South and Midwest tend to be higher than those in more populated areas. The system also allows patients with more resources to work the system. Steve Jobs once bought a house in Memphis so he could join Tennessee's waiting list, which is much shorter than California's where his primary residence was located.

Transplant centers in less populated areas fear the proposed change will allow big-city centers to poach from their supply of organs. That's why the proposal has created something of a turf battle among urban and rural transplant centers.

It's not just patient care that concerns rural transplant centers. Transplants are extremely lucrative for the hospitals that perform them. According to a consulting firm, a single liver transplant results in $800,000 in billed charges. Dr. Seth Karp, director of Vanderbilt Medical Center's program says the change could force smaller programs to close or scale significantly back.

"If the program in Mississippi closes, if the program in Iowa closes because of this, that's a real national public health problem," he said.

To keep the distribution from going into effect, transplant centers in the South and Midwest filed suit in late April. A temporary restraining order was denied on May 13, but a U.S. district judge issued a cease and desist order upon appeal. That means organs continue to be distributed within the 11 geographic regions until the case is taken up in court again.

UNOS has always maintained the new distribution method will save lives.

"This is good news for the sickest candidates waiting for livers," said Brian Shepard, CEO of UNOS, in an interview with NPR. He said 100 additional lives would be saved each year with a more efficient distribution method. "Targeting the livers towards those folks who are really the most critically ill will result in fewer people dying on the waiting list."