Click and
Cut in the
Virtual OR
A tracheotomy to put
a breathing tube in the
throat of an infant can be
a risky procedure, says Dr.
Court Cutting, a leading plas-
tic surgeon at New York Unii
versity Medical Center; it runs
the danger of cutting the supe-
rior thyroid artery, which can
cause blood to spurt out as fast
as it can be sucked up. The
surgeon probably won't make
that mistake again, but it can
be tough luck for the baby.
Talking with a pilot friend one
day, Cutting realized that the
way we teach surgeons is like
training pilots by sending
them up in loaded 747s—
loaded mostly with poor people,
since the affluent seek out
experienced doctors as private
patients. But pilots learn to fly
on simulators. Why can't sur-
geons practice on machines,
instead of bodies?
They already do, but exist-
ing devices all have shortcom-
ings. Cutting himself has devel-
oped a videogame-based
system for teaching cleft-lip
and -palate repair, and there are
programs for cardiac surgeons
to practice threading catheters
up the femoral artery to the
 VIRTUALLY SMILING: Soon surgeons will practice correcting a cleft lip and palate in real-time simulation—the way pilots learn to fly |
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heart. But those are based on generic anatomical models. Cutting wanted the ability to rehearse an operation on a vir- tual model of a real patient's actual anatomy, based on CT or MRI scans. And he wanted to be able to do it in real time, interactively, on a model incor- porating skin, muscle, nerves, organs, bones—and blood. How hard can that be? Well, equations exist to calcu- late how tissues will stretch or tear when a surgeon manipu- |
lates them, and how they will respond when they're sutured up again. But on existing desk- top computers they can take days to solve, says Joseph Ter- an, a UCLA mathematician who is organizing a conference on "virtual surgery" at the uni- versity next month. To show the effects in real time on a screen, you have to do the cal- culations in one thirtieth of a second. To create the illusion of actually wielding a scalpel or hook—using a device that |
resistance, analogous to the
joystick on a flight simulator—
requires reducing the lag time
to one thousandth of a second.
Essentially, you'd need to put
the power of a supercomputer
into a desktop. Cutting thinks
this will be achievable, using
multiple parallel processors
and new algorithms Teran is
developing, within a couple of
years. "You could have a pa-
tient in a small town scanned
while a surgeon in the city
practices the surgery," Teran
says. "The patient then flies
out for the operation."
And none too soon to
help Iraq War veterans who,
thanks to improved body ar-
mor, are now surviving attacks
that would have been fatal in
earlier wars, but are left with
severe wounds to their ex-
tremities and faces. Many
other specialties could benefit
as well, including cardiac, can-
cer and orthopedic surgery,
and Cutting's own field of
cleft-lip and -palate repair;
there are 40,000 cleft babies
born every year in China
alone. "No two traumas or
birth defects are the same,"
says Teran. "The surgeon
makes a plan to repair the
damage, only nothing goes ac-
cording to plan." Better, in that
case, for the virtual patient to
bleed on the screen—than the
real one in the operating room.
—JERRY ADLER
