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Treatment Strategy: Fetal vs. Postnatal Surgery

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The MOMS trial established that fetal (prenatal) surgery for open spinal dysraphism significantly reduces the need for a brain shunt and improves a child's mobility compared to postnatal surgery. However, fetal surgery involves maternal risks and requires strict medical eligibility.

Key Takeaways

  • • Fetal surgery aims to stop the progressive damage to the spinal cord caused by amniotic fluid exposure during pregnancy.
  • • Prenatal repair reduces the need for a VP shunt from historic rates of 80-90% down to 40-50%.
  • • Children who undergo prenatal repair show improved mobility and a reduced severity of Chiari II malformation compared to those who have postnatal surgery.
  • • Mothers must meet strict eligibility criteria for fetal surgery, including specific BMI limits and infectious disease screening.
  • • Open fetal surgery and minimally invasive fetoscopic repair carry distinct risks for the mother, including preterm labor and uterine scar complications.

One of the most significant decisions you will face is choosing when and how your baby’s spinal defect should be repaired. There are two main paths: prenatal (fetal) surgery (done while the baby is still in the womb) and postnatal surgery (done within the first few days after birth).

The Rationale for Fetal Surgery: Stopping the “Second Hit”

As we discussed in the orientation, the two-hit hypothesis suggests that the spinal cord is progressively damaged by ongoing exposure to amniotic fluid in the womb [1][2]. The primary goal of fetal surgery is to interrupt this “second hit” by achieving prenatal closure [3][4]. Doing so reduces secondary damage to the neural tissue, with the goal of improving long-term neurological outcomes [3][4].

The MOMS Trial: What the Research Shows

The Management of Myelomeningocele Study (MOMS) was a landmark clinical trial that established in utero repair as the standard of care for eligible patients [3][5][6]. It proved that prenatal surgery, compared to postnatal repair, offers significant benefits:

  • Reduced Need for Shunts: Prenatal closure drastically reduces the need for a VP shunt to manage hydrocephalus. The MOMS trial demonstrated a reduction in shunt dependency from historic rates of 80-90% down to 40-50% after fetal repair [7][8][9].
  • Improved Mobility: Children who undergo prenatal repair show favorable ambulation status, increasing the likelihood of independent ambulation compared to those who have postnatal surgery [10][11][12].
  • Brain Health: Fetal repair reduces the incidence and severity of the associated Chiari II malformation (hindbrain herniation) [13][14][15].

Note: While fetal surgery improves outcomes, it is not a cure. The majority of children will still require orthotics or assistive devices for walking, and outcomes heavily depend on the initial anatomical level of the lesion [16][10][17].

Comparing Surgical Approaches

If you are evaluating your options, it helps to understand the differences between the three main surgical paths:

Feature Postnatal Surgery Open Fetal Surgery (MOMS Approach) Fetoscopic Repair (Minimally Invasive)
Method Surgery performed on the baby after birth, often on the day of delivery [18][19]. An open surgical incision (hysterotomy) is made in the mother’s uterus to reach the baby [11][20]. Small “ports” and cameras are used to repair the defect through tiny incisions [17][21].
Delivery Method Vaginal delivery or standard C-section; baby goes to surgery shortly after birth [18]. Requires a C-section for this delivery and all future births [11][20][10]. Eliminates the risk of uterine scar dehiscence, potentially allowing for vaginal delivery [11][20][10].
Maternal Risk Standard delivery risks. Inherent maternal risks, including uterine scar thinning or dehiscence (rupture) [11][20][10]. Longer operative times and higher rates of preterm prelabor rupture of membranes (PPROM) [22][10][20].
Shunt Risk High risk (75-90%) of needing a VP shunt [23][24][7]. Reduced risk (40-50%) of needing a VP shunt [7][8][9]. Associated with a higher requirement for postnatal reoperation compared to open repair [22][10][20].

What to Expect with Postnatal Surgery

If you choose not to have fetal surgery, or if you do not meet the maternal eligibility criteria, your baby will undergo postnatal repair. This means a pediatric neurosurgeon will perform the surgical closure of the defect on the day of birth [18][19][25]. They will reconstruct the neural placode and close the associated skin defect to protect the spinal cord from infection [18][26][19]. Following birth, a significant proportion of these patients will still need a VP shunt implanted within the first year to manage hydrocephalus [27][28][25].

Maternal Eligibility Criteria for Fetal Surgery

Fetal surgery is a major procedure, and maternal safety is paramount. The MOMS trial established strict eligibility criteria [29][30][10]:

  • BMI Limits: Historically, mothers were excluded if their Body Mass Index (BMI) was greater than 35 kg/m\u00b2 due to complication risks. However, some contemporary centers now extend eligibility to patients with a BMI between 35 and 40 kg/m\u00b2 [31][32].
  • Infectious Disease: A positive maternal Hepatitis B virus (HBV) status is a specific exclusion criterion [33].
  • Fetal Anatomy: Eligibility also depends on the fetus having specific anatomical requirements, such as a suitable lesion level and the presence of leg movement [34][17].

Choosing between these options involves balancing the potential neurological benefits for your child with the inherent risks to the mother’s health and future pregnancies. Regardless of the path you choose, specialized multidisciplinary care is essential for optimizing outcomes [35][36][17].

Frequently Asked Questions

What is the difference between fetal and postnatal surgery for open spinal dysraphism?
Fetal surgery is performed while the baby is still in the womb to repair the spinal defect before birth and prevent further nerve damage. Postnatal surgery is performed by a pediatric neurosurgeon within the first few days after the baby is born.
Why is prenatal surgery recommended for myelomeningocele?
Fetal surgery helps stop the ongoing damage to the spinal cord caused by exposure to amniotic fluid in the womb. It can significantly reduce the need for a brain shunt, improve future walking ability, and lessen the severity of hindbrain herniation.
Will my baby need a VP shunt if we choose postnatal surgery?
Babies who undergo postnatal surgery have a 75% to 90% risk of needing a VP shunt within their first year to manage hydrocephalus. Fetal surgery lowers this risk to roughly 40% to 50%.
How do I know if I am eligible for fetal surgery?
Eligibility depends on strict maternal health criteria, such as specific Body Mass Index limits and being negative for Hepatitis B. The baby must also meet anatomical requirements, including having a suitable lesion level and leg movement.
How does open fetal surgery compare to fetoscopic repair?
Open fetal surgery requires an incision in the mother's uterus to reach the baby, which means all future deliveries must be via C-section. Fetoscopic repair is a minimally invasive approach using small cameras and ports, which may allow for future vaginal deliveries but carries a higher risk of preterm membrane rupture.

Questions for Your Doctor

  • • Based on the MOMS trial criteria, does my baby's specific lesion level and gestational age make them a candidate for prenatal surgery?
  • • Do I meet all the maternal eligibility criteria, including BMI limits and infectious disease status, for fetal surgery at this center?
  • • What is your center's experience with 'open fetal surgery' versus 'fetoscopic repair,' and which do you recommend for my specific situation?
  • • If we choose prenatal surgery, what are the specific risks of preterm labor or uterine scar issues for me, both now and in future pregnancies?
  • • If we opt for postnatal surgery, what exactly happens on the day of delivery, and how long can we expect our baby to stay in the hospital?

Questions for You

  • • What are our primary goals for our child's future (e.g., maximizing mobility, reducing the need for brain shunts), and how does each surgery align with those?
  • • Am I physically and emotionally prepared for the potential of extended bed rest or a high-risk pregnancy if we choose fetal surgery?
  • • How do we feel about the risks to the mother's health versus the potential benefits for the baby?
  • • Do we have the necessary support system (family, friends, financial) to manage the specialized care and travel that fetal surgery often requires?

Want personalized information?

Type your question below to get evidence-based answers tailored to your situation.

References

  1. 1

    Spina bifida as a congenital neurodevelopmental condition: Developing a philosophy of health care transition across the lifespan.

    Castillo J, Thibadeau JK, Witt E, et al.

    Journal of pediatric rehabilitation medicine 2025; (18(4)):253-255 doi:10.1177/18758894251394504.

    PMID: 41213895
  2. 2

    Advances in Fetal Repair of Spina Bifida Integrating Prenatal Surgery, Stem Cells, and Biomaterials.

    Evangelista A, Ruccolo L, Friuli V, et al.

    Biomedicines 2026; (14(1)) doi:10.3390/biomedicines14010136.

    PMID: 41595670
  3. 3

    Fetal myelomeningocele repair: a narrative review of the history, current controversies and future directions.

    Yamashiro KJ, Farmer DL

    Translational pediatrics 2021; (10(5)):1497-1505 doi:10.21037/tp-20-87.

    PMID: 34189108
  4. 4

    Fetal surgery for spina bifida.

    Dewan MC, Wellons JC

    Journal of neurosurgery. Pediatrics 2019; (24(2)):105-114.

    PMID: 31370010
  5. 5

    From Sheffield to the Management of Myelomeningocele Study: The Modern Era of Myelomeningocele Management.

    Teasley DE, Adapa AR, Fogel H, et al.

    World neurosurgery 2025; (199()):123985 doi:10.1016/j.wneu.2025.123985.

    PMID: 40685173
  6. 6

    Open fetal surgery for neural tube defects.

    Moldenhauer JS, Flake AW

    Best practice & research. Clinical obstetrics & gynaecology 2019; (58()):121-132 doi:10.1016/j.bpobgyn.2019.03.004.

    PMID: 31078425
  7. 7

    Correlation of fetal ventricular size and need for postnatal cerebrospinal fluid diversion surgery in open spina bifida.

    Agrawal S, Al-Refai A, Abbasi N, et al.

    Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology 2022; (59(6)):799-803 doi:10.1002/uog.24767.

    PMID: 34523765
  8. 8

    Advances in Fetal Surgical Repair of Open Spina Bifida.

    Chmait RH, Monson MA, Chon AH

    Obstetrics and gynecology 2023; (141(3)):505-521 doi:10.1097/AOG.0000000000005074.

    PMID: 36735401
  9. 9

    Risk factors for shunting at 12 months following open fetal repair of spina bifida by mini-hysterotomy.

    Neves da Rocha LS, Bunduki V, Cardeal DD, et al.

    Journal of perinatal medicine 2023; (51(6)):792-797 doi:10.1515/jpm-2022-0212.

    PMID: 36976874
  10. 10

    Experience of 300 cases of prenatal fetoscopic open spina bifida repair: report of the International Fetoscopic Neural Tube Defect Repair Consortium.

    Sanz Cortes M, Chmait RH, Lapa DA, et al.

    American journal of obstetrics and gynecology 2021; (225(6)):678.e1-678.e11 doi:10.1016/j.ajog.2021.05.044.

    PMID: 34089698
  11. 11

    Closing the Gap: Prenatal Repair and the Reimagined Future of Spina Bifida.

    Aydin E, Peiro JL, Habli M

    Clinical obstetrics and gynecology 2025; (68(3)):383-386 doi:10.1097/GRF.0000000000000960.

    PMID: 40697157
  12. 12

    Spina bifida.

    Copp AJ, Adzick NS, Chitty LS, et al.

    Nature reviews. Disease primers 2015; (1()):15007 doi:10.1038/nrdp.2015.7.

    PMID: 27189655
  13. 13

    Arnold-Chiari Malformations in Pediatric Patients After Fetal Surgery for Meningomyelocele.

    Kohútková M, Horn F

    Journal of clinical medicine 2024; (13(22)) doi:10.3390/jcm13226721.

    PMID: 39597865
  14. 14

    What has changed in pediatric neurosurgical care in spina bifida? A 30-year UAB/Children's of Alabama observational overview.

    Blount JP, Hopson BD, Johnston JM, et al.

    Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery 2023; (39(7)):1791-1804 doi:10.1007/s00381-023-05938-9.

    PMID: 37233768
  15. 15

    Detailed Analysis of Hydrocephalus and Hindbrain Herniation After Prenatal and Postnatal Myelomeningocele Closure: Report From a Single Institution.

    Flanders TM, Heuer GG, Madsen PJ, et al.

    Neurosurgery 2020; (86(5)):637-645 doi:10.1093/neuros/nyz302.

    PMID: 31432079
  16. 16

    Motor function outcomes in children with open prenatal repair of Spina Bifida Aperta at 36-month follow-up: The Zurich cohort.

    Brun B, Wille DA, Schauer SM, et al.

    Journal of pediatric rehabilitation medicine 2023; (16(4)):595-604 doi:10.3233/PRM-220096.

    PMID: 38160370
  17. 17

    The first experience with 16 open microsurgical fetal surgeries for myelomeningocele in Germany.

    El Damaty A, Elsässer M, Pfeifer U, et al.

    European journal of paediatric neurology : EJPN : official journal of the European Paediatric Neurology Society 2025; (55()):79-86 doi:10.1016/j.ejpn.2025.03.009.

    PMID: 40154034
  18. 18

    Rotation flap closure of a giant dorsolumbar myelomeningocele: technical note.

    Gomar-Alba M, Vargas-López AJ, Narro-Donate JM, et al.

    Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery 2021; (37(4)):1323-1326 doi:10.1007/s00381-020-05021-7.

    PMID: 33454814
  19. 19

    Myelomeningocele - a single institute analysis of the years 2007 to 2015.

    Januschek E, Röhrig A, Kunze S, et al.

    Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery 2016; (32(7)):1281-7 doi:10.1007/s00381-016-3079-1.

    PMID: 27086130
  20. 20

    Achieving water-tight open spina bifida closure through a novel three-port three-layer fetoscopic repair.

    Bowman R, Alhajjat A, Muller R, et al.

    American journal of obstetrics & gynecology MFM 2025; (7(7)):101697 doi:10.1016/j.ajogmf.2025.101697.

    PMID: 40368003
  21. 21

    Fetoscopic Myelomeningocele Repair with Complete Release of the Tethered Spinal Cord Using a Three-Port Technique: Twelve-Month Follow-Up-A Case Report.

    Pastuszka A, Zamłyński M, Horzelski T, et al.

    Diagnostics (Basel, Switzerland) 2022; (12(12)) doi:10.3390/diagnostics12122978.

    PMID: 36552985
  22. 22

    Fetoscopic versus Open Repair for Spina Bifida Aperta: A Systematic Review of Outcomes.

    Joyeux L, Engels AC, Russo FM, et al.

    Fetal diagnosis and therapy 2016; (39(3)):161-71 doi:10.1159/000443498.

    PMID: 26901156
  23. 23

    Hydrocephalus in Spina Bifida.

    Blount JP, Maleknia P, Hopson BD, et al.

    Neurology India 2021; (69(Supplement)):S367-S371 doi:10.4103/0028-3886.332247.

    PMID: 35102990
  24. 24

    Early Outcome of Endoscopic Third Ventriculostomy With Choroid Plexus Cauterization Versus Ventriculoperitoneal Shunt as Primary Treatment of Hydrocephalus in Children With Myelomeningocele: A Prospective Cohort Study.

    Adebayo BO, Kanu OO, Bankole OB, et al.

    Operative neurosurgery (Hagerstown, Md.) 2021; (21(6)):461-466 doi:10.1093/ons/opab314.

    PMID: 34662909
  25. 25

    Analysis of Denver Neurodevelopmental Screening Test Results of Myelomeningocele, Hydrocephalus, and Microcephaly Patients.

    Alatas I, Canaz G, Arslan G, et al.

    Journal of pediatric neurosciences 2018; (13(1)):28-33 doi:10.4103/JPN.JPN_156_17.

    PMID: 29899768
  26. 26

    Ethical and Legal Dilemmas Around Termination of Pregnancy for Severe Fetal Hydrocephalus, Spina Bifida Aperta and Meningomyelocoella.

    Cerovac A, Serak A, Zukic H, et al.

    Medical archives (Sarajevo, Bosnia and Herzegovina) 2019; (73(2)):126-130 doi:10.5455/medarh.2019.73.126-130.

    PMID: 31391703
  27. 27

    Percutaneous minimally invasive fetoscopic surgery for spina bifida aperta. Part III: neurosurgical intervention in the first postnatal year.

    Graf K, Kohl T, Neubauer BA, et al.

    Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology 2016; (47(2)):158-61 doi:10.1002/uog.14937.

    PMID: 26138563
  28. 28

    CENTRAL NERVOUS SYSTEM LIGNOCAINE TOXICITY IN AN INFANT FOLLOWING VENTRICULO-PERITONEAL SHUNT AND SPINA BIFIDA REPAIR: A CASE REPORT.

    Kituu N, Mugenya WO, Kituyi PW

    East African medical journal 2012; (89(2)):71-2.

    PMID: 26845815
  29. 29

    Benchmarking against the MOMS Trial: Zurich Results of Open Fetal Surgery for Spina Bifida.

    Möhrlen U, Ochsenbein-Kölble N, Mazzone L, et al.

    Fetal diagnosis and therapy 2020; (47(2)):91-97 doi:10.1159/000500049.

    PMID: 31167195
  30. 30

    Fetoscopic Open Neural Tube Defect Repair: Development and Refinement of a Two-Port, Carbon Dioxide Insufflation Technique.

    Belfort MA, Whitehead WE, Shamshirsaz AA, et al.

    Obstetrics and gynecology 2017; (129(4)):734-743 doi:10.1097/AOG.0000000000001941.

    PMID: 28277363
  31. 31

    MOMS Plus: Single-Institution Review of Outcomes for Extended BMI Criteria for Open Fetal Repair of Myelomeningocele.

    Hilton SA, Hodges MM, Dewberry LC, et al.

    Fetal diagnosis and therapy 2019; (46(6)):411-414 doi:10.1159/000499484.

    PMID: 31048584
  32. 32

    Reproductive outcomes following open maternal-fetal surgery for myelomeningocele closure: analysis of MOMS trial participants.

    Moldenhauer JS, MacPherson C, Thom EA, et al.

    American journal of obstetrics & gynecology MFM 2025; (7(11)):101765 doi:10.1016/j.ajogmf.2025.101765.

    PMID: 40886957
  33. 33

    In utero Hepatitis B Immunization during Fetal Surgery for Spina Bifida.

    Moehrlen U, Elrod J, Ochsenbein-Kölble N, et al.

    Fetal diagnosis and therapy 2020; (47(4)):328-332 doi:10.1159/000503447.

    PMID: 31722359
  34. 34

    Parental Management Choices and Discordant Ultrasound Findings in Referrals for Fetal Spina Bifida.

    Van den Eede E, Vergote S, Van der Veeken L, et al.

    Prenatal diagnosis 2024; (44(13)):1628-1634 doi:10.1002/pd.6677.

    PMID: 39384410
  35. 35

    Maternal-fetal surgery for myelomeningocele longitudinal follow-up model: Mitigation of care fragmentation through care coordination and outcomes reporting.

    Castillo J, Locastro MM, Corroenne R, et al.

    Journal of pediatric rehabilitation medicine 2025; (18(2)):146-154 doi:10.1177/18758894251331335.

    PMID: 40221964
  36. 36

    Fetal surgical intervention for myelomeningocele: lessons learned, outcomes, and future implications.

    Danzer E, Joyeux L, Flake AW, Deprest J

    Developmental medicine and child neurology 2020; (62(4)):417-425 doi:10.1111/dmcn.14429.

    PMID: 31840814

This page provides educational information about surgical options for open spinal dysraphism. Always consult your maternal-fetal medicine specialist and pediatric neurosurgeon to determine the safest treatment approach for you and your baby.

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