Fetal Surgery for Spina bifida: A Birth Defect

Fetal Surgery for Spina bifida: A Birth Defect
Page content

What is Spina bifida?

Spina bifida is a birth defect that occurs in 1-2 per thousand pregnancies. In this, there is an opening in the spinal column of the fetus as a small bit of bone and skin fails to enclose the nerves of the spinal cord. The development is interrupted anywhere from the brain to the spinal cord due to a combination of environmental and genetic factors. This defect is known as spina bifida.This defect occurs early during pregnancy, probably during the third or fourth week following fertilization. There are two forms of this defect:

  1. Spina bifida occulta – In this, the bones of the spinal column are not properly developed but the nerves are normal. Thus there is no paralysis or weakness and this condition is not medically significant.
  2. Myelomeningocoele – In this, the nerves as well as the bones of the spinal column are not developed properly and this is the most severe form of spina bifida.

Indications for Spina bifida Fetal Surgery

Spina bifida can cause a variety of defects like paralysis, weakness of muscles, mental retardation and abnormalities in bladder and bowel function. The degree and type of impairment depends on the level at which the spinal column defect is located. The higher the level, the more severe the impairment.

How is the Spina bifida Fetal Surgery Performed?

This surgery requires closing the defect in the spine when the baby is still in the mother’s womb. Spina bifida open fetal surgery involves opening the mother’s abdomen and uterus, partially removing the fetus and sewing shut the opening in the spinal column. The procedure is performed sometime between 24 and 28 weeks of pregnancy or in the third trimester. At this point of time, the skin of the fetus is well developed and it is easy to perform the procedure.

Detailed ultrasound of the fetus and echocardiogram of the fetal heart is carried out before the procedure. General or epidural anaesthesia is given to the mother. The mother’s abdomen and uterus is opened. The fetus is first moved away from the placenta, the organ which supplies blood to the fetus. A narrow tube is inserted through an incision in the uterus and the amniotic fluid is drained and collected in syringes. Then the fetus is partially removed from the uterus. Using the ultrasound as a guide, the surgeon locates the fetal part to be operated upon. The defect in the spinal column is located and it is sewn shut. After the procedure, the fetus is replaced back into the uterus. The incision in the uterus is closed with stitches. Prior to the final stitch, the amniotic fluid is replaced back into the uterus. Then the abdominal wall is closed.

Risks of Spina bifida Fetal Surgery

Risks to the mother:

  1. Excessive blood loss
  2. Wound or uterine infection
  3. Rupture of uterine incision
  4. Complications of general anaesthesia
  5. Psychological stress
  6. Inability to have further children
  7. Death

Risks to the fetus:

  1. Premature delivery
  2. Cerebral palsy, blindness or brain haemorrhages due to premature birth
  3. Physical deformities
  4. Birth during surgery
  5. Intrauterine infection
  6. Brain damage
  7. Further damage to spinal cord and nerves during surgery
  8. Death

Conclusion

Spina bifida fetal surgery does not regain the loss of neurological function which has already occurred but it can prevent further damage. It has also been found that closing the defect affects the way the brain develops and it prevents hydrocephalus (collection of fluid within the brain) from occurring and thus its complications and further surgeries can be prevented.

References and Further Reading

  1. Management of Myelomeningocoele Study
  2. UCSF Fetal Treatment Centre
  3. Science Daily
  4. Spina Bifida: Management and Outcome By M. Memet Özek, Giuseppe Cinalli, Wirginia J. Maixner