Spare Parts


By Mary Carpenter

THE MAN That Was Used Up,” Edgar Allan Poe’s story from 1836, describes an extremely vain man with a seemingly perfect body that’s discovered to be a total ruse by an early morning visitor, who finds only a small pile of clothing on the floor: the artificial parts have all been removed for sleeping.

In the 21st century, replacement body parts keep improving, even the more prosaic joints—most recently knees, with minimally invasive surgery (MIS) that can be performed using a robot and often as an outpatient procedure. Similar to anterior hip arthroplasty—revolutionary 20 years ago—MIS allows surgeons to enter through a smaller incision in the front of the joint and spare important muscles, compared to older methods.

But the 2021 documentary film They Say It Can’t be Done  highlights an era of an ever-worsening shortage of donor organs for transplantation—and ongoing obstacles to 3D organ printing, as one of four humanity-rescuing innovations currently held up in regulatory bureaucracy.

More than 100,000 Americans at any one time are waiting on very long lists for organ transplants, with more than 20 people dying every day. For most transplantations, organs of deceased donors must match a recipient’s blood type and body size, although kidneys and parts of the liver can come from a living donor, if the tissues match sufficiently and if that person is willing to undergo major surgery.

Among the newest replacement-part possibilities, bioprinting allows for the creation of full-scale 3D components of the human heart and lungs, using new “bioink” gel to create an extracellular matrix that helps suspend the cells. The first transplanted lab-grown human bladder, developed by Anthony Atala at Wake Forest University, allowed Luke Massella to play high school sports, followed by college and a career as a wrestling coach and jewelry event planner, without needing dialysis. But Massella’s transplantation took place 15 years ago; as of today, only about 10 people have benefited from replacement bladders.

Meanwhile the FDA has failed to create a framework for reviewing and approving artificial body parts, despite promising in 2017 to get to work on this. In contrast to the FDA’s bailiwick —mass-produced products like drugs and medical devices—3D-printed and lab-grown organs are one-of-a-kind creations, tailor made for each patient.

Resistance to opening the floodgates to artificial organs comes from many directions, as it does for the three other innovations in the film, including aquaculture to save the oceans. According to Cardwell’s Law, golden eras tend to move towards an “absorbing barrier of technological stagnation”—created by groups believing they will lose something as a result of change.

As the field of tissue engineering was “beginning to coalesce” 30 years ago, experts expected the ability to create brand new organs within several decades. But, said Rice University bioengineer Jordan Miller, “Growing new organs turned out to be a little further off than anyone thought” —though it is now in “striking-distance.”

“You can grow billions of cells in a lab…hundreds of billions of cells at the bottom of a petri dish,” said Miller. What’s usually missing is the architecture, scaffolding needed for a three-dimensional organ: “If you don’t have it, you can’t get nutrients to cells and cells will die.”  Miller expects the first applications of any new technology to be in “bridging treatments,” to keep patients with failing organs alive until a donor organ is available.

The organ procurement process in the U.S. can prove unwieldy from the start. To get on the national list, patients who need transplants must visit a transplant hospital to be evaluated by a multidisciplinary team. When an organ becomes available, the United Network of Organ Sharing generates a list of potential recipients based on blood type, tissue type, organ size and medical urgency of the patient’s illness—as well as time already spent on the waiting list and geographical distance between donor and recipient.

Potential organ recipients need to stay close to a medical center because transplantation must take place within hours of removal to preserve the organ. But obtaining consent from donors or donors’ families can be both time-consuming and challenging. And transplanted organs have high failure rates, with acute rejection episodes occurring in 15% of patients within the first week, and more than half of all organ transplants failing within 10 to 12 years.

For live donations of kidneys or liver parts, individual transplant centers make the arrangements. Among organs and tissues that can be transplanted are the liver, kidney, pancreas, heart, lung, intestine, corneas, middle ear, skin, bone, heart valves and connective tissue. A deceased donor can save up to eight lives and enhance over 75 more.

Recently I learned about the possibility of having a MIS knee replacement—which avoids trauma to the quadriceps muscle, the most important muscle group around the knee.  Compared to traditional knee surgery, MIS can result in less postoperative pain as well as helping to reduce time spent on recovery as well as rehab and therapy.

At the first knee replacement discussion 10 years ago, my physician advised waiting until the pain or dysfunction was much worse, saying, “Otherwise, you will not be pleased.” His point: Replacing body parts requires cutting into the body — and that means it will take time and hard work for that body to recover.

—Mary Carpenter

Mary Carpenter regularly reports on topical issues in health and medicine.


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