Major discoveries in medical science are the most elusive of events. Magical advances like penicillin and the Salk polio vaccine do appear. But, in fact, the so-called breakthrough is rare. No subject is a better example of the deliberate pace of medical research than spinal-cord injury, once considered a dead end for researchers.
For years, doctors believed that damaged nerves in the spinal cord never grew back. Most of the 20,000 patients who suffer spinal injuries each year were thought to be doomed to a life of paralysis.
But recently, researchers have begun to believe that this may not necessarily be true. Laboratory evidence has indicated that the obstacle to a cure for spinal-cord injuries, although formidable, is not insurmountable. New optimism has begun to emerge.
'Big Break a Myth'
The important thing to bear in mind, says Dr. Eugene Flamm of the New York University Medical Center, is that a cure probably won't come all at once. "The big breakthrough is usually a mythical event," says Flamm, vice chairman of the NYU department of neurosurgery, which is one of a small group of spinal-injury centers where such research is being conducted. "Discoveries in research are usually a series of steps, one leading to the next."
Talking about spinal-cord research, Flamm likes to make the analogy of a chain with many links. In spinal-cord-injury research, the chain started in the 1960s when investigators began looking at what happened to the spine right after an injury. "If one went on the assumption that the minute the spinal cord is injured there is a sudden disruption of the cord, then there isn't much you could do," Flamm said.
But, in the vast majority of cases, researchers found that the injured cord was bruised instead of cut in two. The injury itself was likely to touch off a progression of secondary events--bleeding, swelling, a lowering of blood pressure.
"If you looked at the cord immediately, it didn't look so bad," Flamm continued. "In cats, an hour later you began to see blood accumulating. By four hours, you began to see more changes." After 24 hours had passed, Flamm said, the spinal cord was either "necrotic" (dead) or "devastated."
Fast Action May Cut Damage
Next came the concept of a "window in time" when intervention might reduce the damage, he said, because the effects of trauma were not immediate.
That concept sparked a new notion of trying to influence, and possibly limit, trauma after a spinal injury. This led to using drugs in an effort to reduce the extent of paralysis.
Like many advances in science, the drug intervention idea grew out of an experiment going in a totally different direction. At Walter Reed Army Institute of Research in Washington, D.C., Dr. Alan I. Faden, Thomas P. Jacobs and John W. Holaday were investigating the after-effects of severe blood loss.
Specifically, they were zeroing in on the role of the body's natural painkillers, called endorphins, during massive bleeding. Although endorphins do relieve pain after injury, they also seem to trigger blood pressure drops that may lead to shock or even death. To investigate this phenomenon, the three investigators studied naloxone, a drug that could block the effects of heroin and also, they theorized, might block the body's natural opiates.
To test their idea, the Washington investigators induced shock in animals, then injected them with naloxone. The drug did, in fact, block the effects of the body's endorphins. Blood pressure stabilized and shock did not result.
The three investigators were aware that blood pressure also fell after spinal-cord injury, and they thought that the pressure drop caused by endorphins might be responsible for most of the damage. So they decided to study blood-pressure changes in spinally injured animals treated with naloxone. Naloxone did improve the blood-pressure drop, but not by much. Nonetheless, they were startled to find that, after getting naloxone, some animals recovered most of their walking ability.
"We were surprised how dramatic it was," Jacobs said. "Over a six-week period, some animals returned almost to normal. On a scale from one to 10, we rated them eight or nine."
The researchers reported their results in the journal Science. Newspapers picked up the story--some a bit flamboyantly. One paper's somewhat premature headline read: "Cure for Spinal Injuries Discovered."
At NYU, Flamm, impressed with the finding, decided to do his own naloxone study, using cats. It was a decision to embark on a practice that is often clouded by controversy.
Recently, for instance, animal-rights proponents have invaded laboratories in Philadelphia and other cities where they felt animals were being treated cruelly. They want to stop experiments that, they feel, duplicate what is already known or are done only to feed "human vanity" or society's desire for new products and gadgets.