FROM a surgeon’s point of view, open fetal surgery is as good as it gets.
Nancy Chescheir, director of the fetal therapy programme at the University of
North Carolina, admits that it isn’t just Joe Public who is dazzled by this
strange new contact with the unborn. “Fetal surgery is very glitzy, it’s very
glamorous, it’s extremely exciting being in the operating room.” But even
Chescheir, who is entering this pioneering area, acknowledges the
ethical minefield that surrounds it.
When her fetal surgery programme opens its doors at the end of this year,
access will be strictly limited. Parents will have to go elsewhere for the
operation the US media hailed as a miracle—open intrauterine repair of
myelomeningocele, the serious spina bifida lesion in which both spinal cord and
membranes protrude in a sac. As far as Chescheir is concerned, open fetal
surgery is still in the experimental stage. “There will be very few patients for
whom it is an appropriate intervention,” she says. “We are going to deal with
the unusual patient who can give an informed consent.” These “unusual” patients
are women who are carrying fetuses with life-threatening conditions, such as
non-cancerous chest tumours, too obscure to make it onto Oprah.
The ethical dilemma doesn’t simply involve the well-being of the unborn
child. Mothers face two Caesarean sections—the first for the operation,
the second to deliver the child. They risk the rupture of their uterus and must
have all future children by Caesarean. Chescheir, an obstetrician, has an
ethicist on her team, as all fetal surgery centres do. But she hopes that having
an obstetrician rather than a surgeon heading the programme will mean that the
mother’s readiness to sacrifice herself will not be assumed or exploited.
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Her hesitancy, and her faith in the restraining powers of a background in
obstetrics, are slightly surprising, given that she has spent the past few
months learning the fetal surgery trade from Joe Bruner at the Vanderbilt
University Medical Center in Nashville, Tennessee. Bruner is also an
obstetrician, and is the most prominent enthusiast for open fetal surgery for
spina bifida. Along with neurosurgeon Noel Tulipan he has performed 88 open
fetal spina bifida repairs since 1997, when he pioneered the technique, and is
currently clocking up one or two operations a week. Vanderbilt’s operating rate
far outstrips that of the Children’s Hospital of Philadelphia (CHOP), the only
other centre currently offering open repairs. The CHOP team, working under
strict patient selection criteria, has operated on 18 fetuses.
Critics of open fetal surgery for spina bifida claim it is bad for the mother
and of uncertain value to the fetus. Bruner describes his website,
www.fetalsurgeons.com, as an online brochure. This makes other doctors
uneasy. Neurosurgeon Carys Bannister, president elect of the Society for
Research into Hydrocephalus and Spina Bifida says: “What we should be doing is
giving parents information to make an informed decision.” Though the site says
that staff “meet with the patients to make sure that they understand the risks
and benefits of this surgery and are fully able to make a competant
Dz”.
The fetal repair technique promoted by Bruner and others closes the exposed
part of the spinal cord. But spina bifida is a “whole central nervous system
abnormality”, which can only be marginally improved by such a “minor
adjustment”, says Bannister, who operates at the Manchester Children’s
Hospital.
But while most British surgeons appear sceptical about open repairs, some are
keen to get involved. Jonathan Punt, a paediatric neurosurgeon at the University
of Nottingham says that he would be “very interested” if there was parent
demand, and would consider running a study.
Russell Jennings, director of the recently established fetal surgery
programme at the Children’s Hospital in Boston, worries there might be an
economic incentive to perform the operation. “There are about 2500 cases
diagnosed a year in the US: that is a huge number of potential patients.” Each
operation carries a charge of over $30 000.
Like Chescheir, Jennings thinks open fetal surgery should be restricted for
the time being to rare conditions where the benefits are more assured. “There’s
tons of other stuff to do, that just doesn’t have the media coverage. I removed
a huge neck tumour from a fetus a month ago.” He is highly critical of Bruner’s
willingness to perform the operation.
Michael Harrison, who performed the first open operation on a fetus in
California in 1981 (for the removal of a life-threatening urinary tract
blockage) is also critical. He says there’s nothing like enough evidence that
the intrauterine repairs attempted by Bruner work better than the postnatal
surgery most babies with spina bifida receive. “It’s a possibility that in a few
years from now we will look back and say that 100 cases were operated on, with
very significant risk to the mother, for nothing.”
Bruner can point to his small study, reported in The Journal of the
American Medical Association (vol 282, p 1819) last November, suggesting
that his methods do reduce the incidence of complications resulting from spina
bifida. The same report acknowledges that his technique increases the risk of
premature birth.
But according to Harrison, the furore over open fetal repairs is a side
issue. He says the future of fetal surgery lies with minimally invasive
techniques, which are safer for the mother and far less likely to trigger a
premature birth. With his team at the University of California at San Francisco
(UCSF) he is ironing out the technical problems which in the 1980s made
endoscopes seem too dangerously fiddly for spina bifida. His fetal endoscope
utilises miniature instruments and telescopes mounted on thin, flexible wires to
enable surgeons to perform the most delicate procedures inside the uterus, while
the fetus floats in amniotic fluid.
Harrison has used his endoscope successfully on cases of twin-twin
transfusion—a condition in which one twin fatally drains the other of
fluid and blood—and congenital diaphragmatic hernia, a lung abnormality
which kills the baby when it takes its first breaths. He is confident the
technique will allow a hugely increased range of lethal and non-life-threatening
conditions, from bone marrow disease to cleft palate, to be operated on in the
womb. But he is not prepared to operate on spina bifida cases unless he can work
within “a proper randomised trial”.
Unfortunately, the chances of such a trial are beginning to look remote, at
least in the consumer-dominated US. Almost all the surgeons New
Scientist spoke to thought parents would be unwilling to be assigned to a
control group. Instead, they would almost certainly travel to whichever centre
would give them the operation.
Even if the big three (Vanderbilt, CHOP and UCSF) agreed to operate only
within a controlled trial setting, parents with money will soon have other
places to go. “I get a phone call a week from a neurosurgeon wanting to start
their own programme,” says Leslie Sutton, chief of neurosurgery at CHOP. He says
he has heard from “all sorts of people—it is only a matter of time”.
Sutton is in a hurry to mount “some sort of trial”. He says: “Once everybody out
there is doing this, then we have lost all hope because it will just become a
commercial enterprise.”
While the ethical debate rages on, the doctors and surgeons are already
looking for new challenges. Harrison has his endoscope. Jennings thinks that
tissue engineering is “the way to go to fix the spina bifida kids”. He says he’s
growing oesophagus, and his centre is in the early stages of growing spinal
cord.
Even Bruner is predicting that open fetal surgery will not last more than
another generation. He is making plans to use space-age robotics with virtual
imaging. The latest robotics are intuitive and minimally invasive: when the
surgeon moves his hand left, the 3D image he watches on a TV screen will also
move left. “The other advantage,” says Bruner, “is that you don’t have to be
there. I could be sitting on a beach operating on a patient in London.” Imagine
the headlines.
