Neurology Now:
doi: 10.1097/01.NNN.0000300603.82702.da
Department: the Waiting Room: This Way in

A COOL IDEA

Cajigal, Stephanie

Free Access

IIt speaks to the power of medicine when in six weeks a person can go from being paralyzed from the shoulders down to taking small steps.

The recovery of Buffalo Bills' tight end Kevin Everett, who fractured his cervical spinal cord in a Sept. 9 season opener with the Denver Broncos, is being closely watched by football fans and medical experts alike. His story not only offers hope for people with spinal cord injuries but also highlights a unique therapy that cools the body: hypothermia.

Everett, 25, fell to the ground after attempting a headfirst tackle of Broncos' Domenik Hixon. After lying motionless on the field for about 15 minutes, Everett was transferred to an ambulance, where orthopedic surgeon Andrew Cappuccino, M.D., lowered his body temperature by infusing him with ice-cold saline.

Within eight days of his injury, Everett showed increased strength in his legs and some movement in both hands, according to a Sept. 17 statement from Bills' team medical director John Marzo, M.D. On Oct. 17, Everett announced that with the assistance of a walker, he'd taken his first steps. His progress could be partially explained by the fact that he didn't snap his spinal cord and therefore preserved some sensation below the area of injury. About 40 percent of people with this type of fracture improve somewhat, consulting neurosurgeon Kevin Gibbons, M.D., told the media on Sept. 12.

“Did hypothermia have any effect on [Everett's] improved outcome? We don't know, because it's just one patient,” says W. Dalton Dietrich, Ph.D., scientific director of the Miami Project to Cure Paralysis, which is a leader in hypothermia research. “It's still an experimental treatment; it's not a standard of care.”

Cooling the body prevents many of the inflammatory cascades that lead to cell death immediately after a stroke, brain injury, or spinal cord injury, Dr. Dietrich says. Existing drugs usually target only one of these damaging mechanisms. “We now know that those [drugs] might not work in very complicated brain and spinal cord injuries,” he says.

Hypothermia, according to Dr. Dietrich, works against four processes that are usually triggered after a spinal cord injury: an increase of water in the spinal cord that causes swelling of tissue and compression of the cord (edema); inflammatory responses that lead to the death of spinal cord cells; the formation of free radicals, which damage cells; and apoptosis, a mechanism by which cells generate proteins that lead to their own death.

“Hypothermia blunts these processes and sometimes inhibits them completely,” Dr. Dietrich says.

Researchers in Miami are studying the use of hypothermia in people with brain or spinal cord injuries. A cooling catheter is inserted into patients' large blood vessels to lower their body temperatures to 33 degrees Celsius. (Normal body temperature is about 37 degrees Celsius). Cooling is maintained for 48 hours followed by a re-warming of one degree every eight hours.

Hypothermia has been around since at least the 1960s, says Dr. Dietrich, but it is not widely used, and most of the studies have been done in animals. This is because until recently, doctors have had trouble inducing and maintaining people at a cool temperature. New devices, such as cooling vests, helmets, and catheters, have made the process easier, he says.

The treatment does have risks. Eugene Fu, M.D., associate professor of clinical anesthesiology at the University of Miami, says that since cooling the body lowers its immune defense, hypothermia can expose people to infections. In addition, it can disrupt the process of blood clotting, which can increase the amount of blood lost during surgery, and in some people hypothermia can worsen ischemic heart disease, he says.

Figure. Six weeks af...
Figure. Six weeks af...
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Stephan A. Mayer, M.D., director of the Neuro-ICU at New York Presbyterian Hospital-Columbia University Medical Center, has been using hypothermia for stroke, cardiac arrest, and brain injury since 1996. Dr. Mayer, a consultant for Medivance, a company that makes a cooling device, says hypothermia reduces elevated intracranial pressure (which can cause brain damage) in people with these injuries. The benefits are clear, he says: “I know that in facing almost certainly a lifetime of paralysis, if there's even a chance that it will protect my spinal cord and get me better, I'd want it.”

Stephanie Cajigal

©2007 American Academy of Neurology

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