A year ago, Tom Carlo's back was killing him. And now it's simply threatening to send him into bankruptcy.

Carlo, 63, has struggled for more than 40 years with back pain, since falling out of the second floor of an Air Force barracks in 1968, when his unit was under attack in Vietnam. Last spring, he was unable to sit for very long because of the pain, and he was taking drugs that were wrecking his stomach. He opted for a spinal surgery -- his third -- recommended by a doctor.

The surgery was supposed to lead to a cure from pain, and Carlo has found some relief. But his financial problems were just beginning. In June, his insurance carrier, CareAllies, OK'd the operation. In July, Carlo checked into Winthrop-University Hospital in Mineola. In August, CareAllies reversed its decision and denied payment to the two surgeons who operated.

"When the insurance company gives you the OK, you figure, let's do it," Carlo said. "Two months later they told me I should have tried physical therapy or shots -- well, it's too late now."

This is an unpredictable moment in the business of medicine, with costs soaring, the federal government rewriting rules, and insurance companies and doctors vying for some control over the inevitable changes. But people like Tom Carlo, a retired U.S. Postal Service letter carrier who drives a school bus in Garden City, shouldn't have to bear the brunt of these tectonic shifts. He appears to be caught by an insurance carrier balking at astronomical fees from an out-of-network doctor.

New York, unlike other states such as New Jersey, doesn't have a law against excessive billing.

CareAllies, a unit of Cigna, provides health services under contract to the National Association of Letter Carriers. Carlo's plan is a PPO -- a preferred provider organization -- which supposedly gives him the freedom to shop around for a surgeon, provided he shoulders a greater share of the bill. PPOs often pay 70 percent of the "usual and customary" costs of out-of-network care.

The whopper surgeons' bills may have had something to do with CareAllies' change of heart. The primary surgeon billed $355,000, and the assistant surgeon $160,750. Enough to pay for Carlo's tidy Wantagh house and then some.

He has appealed the decision up the chain to the U.S. Office of Personnel Management, which is ultimately responsible for the letter carriers' insurance contract. A representative of that office didn't return phone calls for this story. In a letter to Carlo, CareAllies said that his records had been checked as part of a random audit, and that an independent reviewer had determined the surgery was not medically necessary. Winthrop Hospital and Cigna said they will look into Carlo's case.

In Nassau County, the "usual and customary" rate for this surgery would have ranged between $49,750 and $64,750, according to Empire BlueCross BlueShield. Dr. Scott Breidbart, Empire's chief medical officer, said that out-of-network billings are an area of heated dispute between insurance companies and doctors.

Normally, the insurance company and the doctor would try to negotiate. But Carlo has been appealing CareAllies' decision for 10 months. If the Office of Personnel Management denies his claim, the next resort will be to sue in federal court -- an exhausting and expensive prospect.

Carlo's tale isn't unique. Medical expenses are a leading cause of bankruptcy. But it's an example of why we need health care reform. It doesn't get much worse than having a $515,750 bill dumped in your lap.

First published in Newsday