Penn's program is being restricted to patients who have lost both hands to trauma or illness. The two applicants - who have been screened and now await suitable donors - are even more disabled; their hands, feet, and the lower parts of their arms and legs had to be amputated because of a life-threatening bloodstream infection.
"The two women we're going to [wait] list are totally dependent, almost like an infant," said Levin, a pioneer of the microsurgical techniques used to connect tiny blood vessels and nerves.
Experts estimate that more than a million American amputees a year could benefit from transplants to restore limbs destroyed by disease, birth defects, or trauma - including war-related injuries.
Still, the fledgling field of "composite tissue" transplantation - so-called because it involves attaching blood vessels, nerves, bone, and soft tissue - has been controversial.
The loss of limbs is not necessarily lethal, unlike major organ failure. Yet hand-transplant patients must take immune-suppressing drugs for the rest of their lives, just like organ recipients. These drugs keep the body from rejecting the unfamiliar tissue but raise the risk of tumors, infection, diabetes, hypertension, and more.
The international hand-transplant registry reports that 64 percent of patients developed serious infections and half suffered metabolic complications such as diabetes.
The success of hand transplants is highly dependent on how much of the arm must also be replaced. The more arm tissue, the more nerves that must regenerate - and the less the hand is likely to regain normal sensation and mobility, even with physical therapy.
That therapy can be grueling.
Last summer, CNN.com quoted the first person to receive a double hand transplant in the United States as saying he regretted undergoing the operation at the University of Pittsburgh Medical Center because "I didn't dream there would be this much therapy." After more than a year of it, he still had little control of his new appendages.
Another crucial factor is the patient's commitment to medication. Australian Clint Hallam, who made history in 1998 when he received a new right hand in Lyon, France, became cavalier about taking immune suppressants and developed rejection. In 2001, at Hallam's insistence, a doctor amputated the transplant.
At Penn, a team of specialists has been assembled to interview and evaluate hand-transplant candidates. The team includes social workers, psychologists, ethicists, and financial counselors, as well as physicians.
"The intensity can't be underestimated," Levin said.
Lindsay Ess, 27, one of the two approved candidates, was questioned "in great detail" about behavior that could be seen as attention-seeking, Levin said.
Ess, of Richmond, Va., graduated with a fashion-merchandising degree from Virginia Commonwealth University in 2007. That summer, she underwent intestinal surgery to treat chronic inflammatory bowel disease. Surgical complications led to the bloodstream infection that almost killed her.
In videos now on YouTube and in a long magazine article (published on http://sportsshooter.com), Ess talks frankly about her transformation from a long-haired beauty obsessed with fitness and body image to a quadruple amputee. Although Ess has learned to walk on prosthetic limbs and produces fashion shows, she must depend on her mother for help with daily living and endure strangers' gawking.
What keeps her going, she says in one video, is the hope that people will be inspired by her struggle.
She declined to be interviewed by The Inquirer about her hopes for hand transplants because she has promised Glamour magazine an exclusive article, according to a Penn representative.
"My role," Levin said, "is to provide the best care for her, given her case. I don't do it because it's going to make her famous. I do it to improve her quality of life. . . . Our goal is to give her the best chance for a good future."
The hand-transplant waiting list will be coordinated through the Gift of Life Donor Program, the nonprofit that recovers and distributes organs in the Philadelphia region. No one can say how quickly a suitable donor is likely to be found; that challenge involves aesthetic issues for the dead as well as the living.
"We want to restore the donor's integrity, too," Levin said, showing a prosthesis that could replace a donated female hand. "We have a great regard and respect" for organ donors' families.
Contact staff writer Marie McCullough at 215-854-2720 or firstname.lastname@example.org.