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Rerouting nerves may aid bladder
control
By Lauran Neergaard
Washington - Needing a wheelchair
isn't always the biggest complaint of people left paralyzed by
spinal cord injury — it's also the loss of bladder control. On
Monday, Michigan doctors began a unique experiment to see if
rerouting patients' nerves just might fix that problem.
It's a delicate operation: Surgeons
cut open a spot on the spine and sew two normally unrelated nerves
together — one from the bladder to one from the thigh — with a
single hair-thin stitch. It will take months for this new nerve
bridge to heal, an anxious waiting period for the first volunteers.
But if it works, merely scratching
the thigh should signal the bladder to empty, allowing patients to
ditch their despised catheters and restore a longed-for degree of
freedom, as well as fewer bladder infections and other serious
complications.
"I've got nothing to lose by doing
this," is the way a cautiously hopeful Kevin Bryant, 19 and
paralyzed from the waist down by a car crash, approached the
experiment.
It's a technique pioneered in China
that is starting to garner international attention — and surgeons at
William Beaumont Hospital in Royal Oak, Mich., hope their new U.S.
study will prove if the approach really is a solution for at least
some patients.
"We're very excited," says Dr.
Kenneth Peters, Beaumont's urology research chief, who headed a team
of doctors that traveled to China last February to watch Dr. Chuan-Gao
Xiao operate at the Huazhong University of Science and Technology.
"We said, 'This is something we
need to study ... to see if we can reproduce this in the U.S.,'"
adds Peters, who in turn invited Xiao into Beaumont's operating room
Monday. If the results hold up, "it would allow us to treat those
patients who have no other alternatives."
Monday's first volunteer: a
49-year-old paralyzed from a car crash, Kevin Conkey of Fenton,
Mich. On Thursday, Bryant, the 19-year-old paraplegic, undergoes the
procedure — in addition to a child with spina bifida, an improperly
formed spinal cord that can cause similar bladder dysfunction.
After infancy, the brain takes over
control of urination. The bladder sends "I'm full" signals up the
spinal cord. Once the person's in an appropriate spot, the brain
signals back to the bladder to empty.
In spinal cord injury and spina
bifida, that control is disrupted, leaving patients either unable to
urinate or constantly wet. They depend on catheters to empty the
bladder every few hours. Still, recurrent infections and even
lifethreatening kidney damage from backed-up bladders are common,
not to mention the inconvenience and even embarrassment the
procedure brings.
"People put so much emphasis on
walking. I don't care if I walk again; that's not the No. 1 thing,"
says Bryant, of Rochester Hills, Mich. Going to the bathroom is
"such a hassle in day-to-day life. I have to schedule my life around
the times when I'm going to catheterize."
Xiao's procedure can't restore
sensation, but uses intact nerves below the spinal injury to try to
create a reflex that bypasses the brain.
"Thinking over the (urination)
process, its final step is just a signal to the bladder to
contract," Xiao explained in an e-mail interview. "Can we find
another way to send a signal to initiate bladder contraction and
voiding?"
First, surgeons remove a piece of
bone alone the lower spine to expose spaghetti-like nerve roots
beneath. They reconnect a lumbar nerve responsible for thigh
sensation to a sacral nerve that would normally open the bladder.
It can take a year, maybe longer,
for the two nerves to grow together, and people with certain bladder
or spine scarring aren't candidates.
But Xiao says 110 spinal cord
injury patients and 230 with spina bifida have undergone the
procedure, including two at New York University where he began the
research years ago. He has reported a fraction of those cases in
respected urology journals, suggesting about 80 percent resume
voiding eventually.
In the Michigan study, doctors plan
to suspend operating after six or eight patients, to resume only
once, if, there are signs of success.
"I'm surprised that more people
haven't done this before," says Dr. John McDonald, spinal cord
injury chief at the Kennedy Krieger Institute and a former physician
for the late Christopher Reeve.
He calls the method a logical next
step from nerve-grafting for other injuries that takes advantage of
primitive bladder reflexes at the spine's base. "It's very
reasonable to take this approach with the bladder."
"As a field, neuroscience is
revisiting the adaptive capabilities of the spinal cord below the
level of the injury," agreed Dr. John Martin, a neurobiologist at
Columbia University Medical Center — but who cautioned patients to
await the research. "Some of these ideas that look good haven't come
to fruition."
There are some risks, Peters
cautioned, including general anesthesia and wound infections. For
children with spina bifida who can walk, rerouting the thigh nerve
causes a small risk of some foot weakness.
And it will be expensive, about
$30,000 to $40,000 a person, he estimated, a tab Beaumont is funding
through a private donor. -- The
Associated Press
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