- Email: [email protected]
Is the case for fetal surgery for spina bifida proven?
NEWS Is the case for fetal surgery for spina bifida proven? his week, two groups independently report that intrauterine surgery to close the myelomeningocele in fetuses with severe forms of spina bifida leads to a substantial decrease in postnatal hindbrain herniation and hydrocephalus. However, warns Carys Bannister, a paediatric neurosurgeon at St Mary’s Hospital, Manchester, UK, “modest short-term benefits were achieved only at the cost of great risk to both fetus and mother”. Results from animal studies suggest that the primary spinal defect in spina bifida is worsened by exposure to secondary injury during gestation. It is thought that closure of the myelomeningocele early in the third trimester may prevent this damage, and with it, some of the physical abnormalities and learning disabilities associated with spina bifida. Joseph Bruner and colleagues (Vanderbilt University Medical Center, Nashville, TN, USA) did intrauterine myelomeningocele repair in 29 fetuses at 24–30 weeks’ gestation using a surgical technique similar to that normally used postnatally. After birth, the need for shunt placement for decompression of the hydrocephalus was significantly lower among study infants than among 23 matched control patients (59% vs 91%; p=0·01). There was also a decreased frequency of hindbrain herniation (38% vs 95%; p<0·001). However, 48% of mothers in the study group devel-
oped oligohydroamnios (low volumes from the two reports. “Although of amniotic fluid) compared with there are hints in our data that spinalonly 4% in the control group, and cord function is improved by the 50% had preterm uterine contracprocedure, this is not proven.” The tions compared with reduced need for 9% of controls. Other shunts does, however, maternal complications have the potential to included uterine rupprovide tremendous ture and obstruction of benefit, he says. the bowel. The average Bannister agrees and gestational age at birth adds that an improvein the study group was ment in hindbrain her33·2 weeks compared niation would be worth with 37 weeks in conachieving, but she trols; five babies in the points out that neither study group were born group has yet assessed before 30 weeks of geswalking ability, bladder tation (JAMA 1999; and bowel function, 282: 1819–25). and cognitive ability in Scott Adzick’s group more than a handful of (Children’s Hospital, Repair in utero or later? the patients treated. Philadelphia, PA, “Neither have investiUSA) looked at a case series of gators from either team looked at the ten patients in whom the myelolong-term effects of intrauterine meningocele was closed in utero with surgery in relation to the mother’s a double layer of acellular human future ability to conceive and carry dermis at 22–25 weeks’ gestation. another child”, she warns. Four of the ten fetuses were delivered In response to the publication of prematurely, and one of these died. the US results, Bannister and other Of the surviving nine, only one members of the Society for Research needed a shunt for hydrocephalus. into Hydrocephalus and Spina Bifida Magnetic resonance imaging revealed included a discussion of the new improvement in the hindbrain hernia developments at their Executive in all nine infants 3 weeks after the Committee meeting in London, UK, surgery and at postnatal follow-up on Nov 13. The committee ques(JAMA 1999; 282: 1826–31). tioned several aspects of both studies. Leslie Sutton, lead author of the In the Vanderbilt study, for example, Philadelphia study stresses that the investigators assessed the developoptimum selection, timing, and techmental outcome of 26 of 29 study nical method of closure is not clear infants at 2–18 months of age using the Bayley Scale of infant development. This is a crude and outdated Consultation document issued on preimplantation genetic diagnosis test, says Bannister; the only reliable On Nov 16, the UK Human Fertilisation and Embryology Authority and the UK way to look at outcome is to follow Advisory Committee on Genetic Testing issued a consultation document on the children up to and through school preimplantation genetic diagnosis (PGD; www.hfea.gov.uk).The document age with a full battery of psychometconsiders the current and potential uses of PGD, a technique that has excited ric tests. “To analyse developmental widespread unease because of the possibility of “designer babies”. At present, outcome properly, the child should PGD is used to test embryos created in vitro for specific genetic disorders or for be followed up for at least 5 years”, the sex of the embryo where the disorder is sex-linked. So far, 200 embryos have concludes Bannister. In fact, she and been tested in the UK at one of the four centres permitted to use the technique; fellow committee members believe about 20 babies have been born. The consultation document poses ten questions that “there is a clear case for completrelated to PGD including: should “the current practice of licensing clinics to ing this follow-up before deciding perform PGD for a limited number of specific serious conditions” continue?; and whether to continue to do intrashould “the use of PGD for any indication be the subject of clinical judgement and uterine surgery for spina bifida”. as such left to practitioners and individual patients to decide?”. The consultation
T
period will last about 4 months. Jane Bradbury Kathryn Senior
THE LANCET • Vol 354 • November 20, 1999
1795
oped oligohydroamnios (low volumes from the two reports. “Although of amniotic fluid) compared with there are hints in our data that spinalonly 4% in the control group, and cord function is improved by the 50% had preterm uterine contracprocedure, this is not proven.” The tions compared with reduced need for 9% of controls. Other shunts does, however, maternal complications have the potential to included uterine rupprovide tremendous ture and obstruction of benefit, he says. the bowel. The average Bannister agrees and gestational age at birth adds that an improvein the study group was ment in hindbrain her33·2 weeks compared niation would be worth with 37 weeks in conachieving, but she trols; five babies in the points out that neither study group were born group has yet assessed before 30 weeks of geswalking ability, bladder tation (JAMA 1999; and bowel function, 282: 1819–25). and cognitive ability in Scott Adzick’s group more than a handful of (Children’s Hospital, Repair in utero or later? the patients treated. Philadelphia, PA, “Neither have investiUSA) looked at a case series of gators from either team looked at the ten patients in whom the myelolong-term effects of intrauterine meningocele was closed in utero with surgery in relation to the mother’s a double layer of acellular human future ability to conceive and carry dermis at 22–25 weeks’ gestation. another child”, she warns. Four of the ten fetuses were delivered In response to the publication of prematurely, and one of these died. the US results, Bannister and other Of the surviving nine, only one members of the Society for Research needed a shunt for hydrocephalus. into Hydrocephalus and Spina Bifida Magnetic resonance imaging revealed included a discussion of the new improvement in the hindbrain hernia developments at their Executive in all nine infants 3 weeks after the Committee meeting in London, UK, surgery and at postnatal follow-up on Nov 13. The committee ques(JAMA 1999; 282: 1826–31). tioned several aspects of both studies. Leslie Sutton, lead author of the In the Vanderbilt study, for example, Philadelphia study stresses that the investigators assessed the developoptimum selection, timing, and techmental outcome of 26 of 29 study nical method of closure is not clear infants at 2–18 months of age using the Bayley Scale of infant development. This is a crude and outdated Consultation document issued on preimplantation genetic diagnosis test, says Bannister; the only reliable On Nov 16, the UK Human Fertilisation and Embryology Authority and the UK way to look at outcome is to follow Advisory Committee on Genetic Testing issued a consultation document on the children up to and through school preimplantation genetic diagnosis (PGD; www.hfea.gov.uk).The document age with a full battery of psychometconsiders the current and potential uses of PGD, a technique that has excited ric tests. “To analyse developmental widespread unease because of the possibility of “designer babies”. At present, outcome properly, the child should PGD is used to test embryos created in vitro for specific genetic disorders or for be followed up for at least 5 years”, the sex of the embryo where the disorder is sex-linked. So far, 200 embryos have concludes Bannister. In fact, she and been tested in the UK at one of the four centres permitted to use the technique; fellow committee members believe about 20 babies have been born. The consultation document poses ten questions that “there is a clear case for completrelated to PGD including: should “the current practice of licensing clinics to ing this follow-up before deciding perform PGD for a limited number of specific serious conditions” continue?; and whether to continue to do intrashould “the use of PGD for any indication be the subject of clinical judgement and uterine surgery for spina bifida”. as such left to practitioners and individual patients to decide?”. The consultation
T
period will last about 4 months. Jane Bradbury Kathryn Senior
THE LANCET • Vol 354 • November 20, 1999
1795