BOSTON (Reuters) - A U.S. surgeon who implanted a nuclear-powered pacemaker into a 20-year-old woman in 1973 says the device is still going strong after 34 years and may have saved money over the long run.

But Dr. Victor Parsonnet of the Newark Beth Israel Medical Center said he is not advocating a return to those devices because they have drawbacks.

In a letter to the New England Journal of Medicine, Parsonnet said despite an original $5,000 price tag -- more than $23,000 in 2007 dollars -- follow-up costs have been about $19,000 compared with $55,000 for a battery-powered pacemaker.

A standard pacemaker probably would have needed replacement four or five times over the past three decades, along with extra monitoring.

The woman, now 54, has tolerated her Numec NU-5 well -- except for the need to repair a connector -- and maintains a normal routine.

Although her pacemaker gives a steady jolt instead of the adjustable pace of current devices and stimulates the heart from a spot that is different from the one preferred by surgeons today, “she hasn’t had a bit of problem and feels fine,” Parsonnet said.

Nuclear pacemakers have been controversial because they are powered by plutonium, one of the most dangerous substances known.

The devices were designed to withstand gunshots and cremation, and last so long they would outlive their hosts, while being shielded well enough to deliver very little radioactivity to the patient.

Parsonnet said 139 people received the first versions of the nuclear pacemaker and even after 88 years, when half the plutonium would have decayed, the batteries would have enough power to drive the circuit.

Most of the devices have outlived their owners.

“Nine of these devices are still in use,” Parsonnet said.

Nuclear pacemakers fell out of favor because lithium batteries were developed that “had a life expectancy that was good enough for almost everybody.”

“Lithium pacemakers will often go 10 to 15 years depending on how it’s programmed,” Parsonnet said, adding “the technology of the electronics ran ahead of the battery technology.”

Today, doctors want to be able to periodically replace older-model pacemakers anyway, as the technology for pacing the heart improves.

“You now have programmability and interrogatability and all those things,” he said. “So it died a natural death.”