Mike Miller's journey into the little-known world of hyperbaric oxygen therapy started with a 10-pound wheel falling on the little toe of his left foot.

The injury ended a Caribbean vacation and caused a wound so gruesome that it threatened to take the foot. But Miller's expensive and months-long series of two-hour sessions in a clear plastic tube had him returning to work around Thanksgiving with two healthy feet and an appreciation for a therapy most identify with divers suffering from "the bends."

"Deep down inside, many figured I was going to get another infection in that foot and it would end up coming off, so it was amazing that everything went as well as it did," said the 51-year-old Williston, N.D., man.

Though a small part of the treatment universe, hyperbaric oxygen therapy is on the rise. The Hennepin County Medical Center reports that the number of civilian hyperbaric facilities in the United States has grown from about 25 in the 1980s to nearly 1,000 today. HCMC opened a new hyperbaric chamber in May, and last year gave more than 3,000 treatments for emergencies and illnesses ranging from carbon monoxide poisoning to life-threatening soft tissue infections.

"This has been around for 50 years. But for a long time, the main role had been for carbon monoxide poisoning and the bends," said Dr. Peter Alden, director of the hyperbaric program at Minneapolis' Abbott Northwestern Hospital. "This [wound care] is a newer trend, with growth in the last eight to 10 years."

The therapy is expensive -- about $10,000 for a full course of treatment at Abbott Northwestern. Medicare and insurance will pay for it, but in limited cases primarily related to wound care and damage from radiation treatment.

The therapy involves pumping pure oxygen into a pressurized room -- usually a clear tube -- to help a patient's lungs and body absorb more oxygen. That stimulates the release of substances called growth factors and stem cells, which promote healing and tissue growth.

Procedure has drawbacks

The treatment also has a dark side.

First, there are side effects that can include temporary nearsightedness and middle- and inner-ear injuries.

There have also been false claims surrounding the treatment, with places promoting it as an alternative to treat everything from AIDS to cerebral palsy to autism. Some even say it destroys disease-causing microorganisms and even cures cancer. Pop star Michael Jackson was once rumored to have slept in a hyperbaric chamber because he thought it would help him live longer and look young.

"They are profiteers, and it's a tragedy," said Stacy Handley, vice president for National Baromedical Services in Columbia, S.C., which provides training and advocacy for hyperbaric medicine.

Said Alden at Abbott Northwestern: "There is a whole dark side of strip-mall places that promote off-label indications."

Handley said that the high cost of hyperbaric therapy, coupled with "the bad reputation" spawned by questionable practices, has caused some payers to pull back on approving the care.

Medicare and insurers once paid for 14 approved conditions to receive hyperbaric therapy, she said. Now, most hospitals treat only five.

While wound care is a growing segment of the therapy, the treatment is not good for wounds that still can heal on their own, Alden said. It won't help heal wounds that have no blood supply. Abbott Northwestern treats only about 40 to 50 patients a year.

"We are pretty selective," Alden acknowledged.

Injured toe

Miller, who was a manager at Tractor Supply in Williston, was straightening up a store aisle in the first week of February when a heavy caster wheel fell off a top shelf onto the little toe of his left foot.

"I hopped around, said a few bad words and then I picked it up and put it away," he said.

The next morning, his pain and his limp didn't go away. He soon went to the doctor and had X-rays. Nothing was broken, although the toenail was loose.

With a Caribbean cruise out of New Orleans just days away, Miller ignored the injury. He left on the trip, hobbled around Bourbon Street and limped onto the cruise ship.

On Super Bowl Sunday his foot was red and swollen. The next morning, his sister, a nurse, looked at his now-gruesome injury and sent him to the ship's doctor. He sent him to a physician in Belize -- and the cruise was over. Air ambulance took Miller to Abbott Northwestern. Infection threatened his kidneys. The wound threatened his foot.

Miller said he had heard of hyperbaric chambers helping divers recover and athletes heal. "But I'm from Minnesota. I'm not a scuba diver," he said.

Still, he began to feel improvement over the course of his treatments, which involved lying in the large acrylic tube and having his ears pop.

"Every time they let me out of the chamber, my foot just seemed a lot pinker," he said. "To me, it just looked better."

Miller would go on to have 20 treatments at Abbott Northwestern and continue his therapy in Monticello while staying with his mother in South Haven, Minn. He ended up having about 40 treatments in all, which lasted two hours each. Workers' compensation covered the cost.

He said his company has lined up another job for him. With therapy, he went from a wheelchair to a walker to a cane to recovery. He can fish and hunt again. Maybe, he said, he will take another trip.

"Some day, I will go on another cruise," he said.

James Walsh • 612-673-7428