BUFFALO, Sept. 15 — In the moments after a serious spinal cord injury paralyzed Kevin Everett of the Buffalo Bills below the shoulders, doctors began an innovative treatment based on a familiar premise: apply ice to reduce swelling.

In this case, though, instead of using ice, doctors chilled Everett from the inside, infusing cold fluids into his veins. The treatment is experimental, though, and medical experts caution that it is impossible to say in an individual case whether it helped or hurt.

Even if it does work, it is not clear whether the chilling has to start immediately, as happened with Everett, or whether it can start later, at a hospital. But the surgeon who operated on Everett is convinced. He said the treatment, known as moderate hypothermia or cold therapy, is responsible for Everett’s ability to move his arms and legs days later.

“I will hang a good portion of my belief in this recovery on cold therapy,” the surgeon, Dr. Andrew Cappuccino, said by phone Friday, “because we don’t normally see this recovery in people with spinal cord injury where cold therapy is absent.”