Hello, and welcome to the Pediatric Rehab Review on Spina Bifida. This is a lecture that was originally developed in 2017 by Dr. Sinner and then recently revised by Dr. Dyke in 2020. By the end of this presentation, you should be able to better understand a little bit of embryology, pathophysiology, and epidemiology of neural tube defects, to understand better what a myelomeningocele lesion is and what it means for the child's function and ambulation prognosis, and then lastly we'll discuss some common complications and management associated with spina bifida. Spina bifida is Latin for split spine. It's a diagnosis that's part of a broader group encompassed by neural tube defects pathology. The development of the CNS occurs very early in pregnancy. You can see in this illustration that the neural tube forms during neurolation and starts to close around the third week of pregnancy at day 21 and should finish closing by day 28 or the fourth week of pregnancy. It closes from a cranial to caudal direction. When the neural tube does not close correctly, it can result in various myelodysplasias. Incomplete closure of the most cranial part will lead to anencephaly, where the cerebral cortex, skull, and overlying tissues are absent. An encephalocele usually occurs at the occipital area of the brain, causing a protrusion of the brain and meninges into a sac-like pocket. More commonly, when the caudal regions do not close properly, this leads to spina bifida, found in the thoracic, lumbar, and sacral region. The most common neural tube defects are anencephaly and myelomeningocele. Spina bifida is a diagnosis in convincing myelomeningocele, meningocele, and spina bifida occulta. The close defects are spina bifida occulta and meningocele. Spina bifida occulta is the mildest form of spina bifida, where only the vertebral body arch does not completely close, with no neurologic involvement. There is commonly a tuft of hair on the skin overlying this area. A meningocele is a defect that includes a protrusion of the meninges, but not the neural elements. Thus, this is typically no neurologic injury. Myelomeningocele, or spina bifida occulta, is an open defect where the cerebral spinal fluid, dura, meninges, and neural components protrude from the defect. For the purpose of this talk, we're going to focus on spina bifida that refers to myelomeningocele. About 90% of children with spina bifida have a myelomeningocele. It includes involvement of the motor and sensory nerves of the spinal cord, and lasting neurologic deficits that most commonly need physiatric care. Pre-pregnancy BMI of greater than 29, and associated maternal diabetes, as well as seeking during the pregnancy, all can increase the risk of neural tube defects in myelomeningocele. Looking at primary prevention, it's recommended that all women of childbearing age take 400 micrograms a day of folate. Whether or not they're planning to become pregnant, as the neural tube defect occurs so early in the pregnancy, it's likely they're not aware that they are pregnant. If they've had a previous pregnancy with a neural tube defect, they're recommended to take four milligrams a day of folate to reduce risk of subsequent child with spina bifida. So let's look at a review question. Which of the following is not a risk factor for having a child with spina bifida? A, maternal diabetes, B, taking deltoic acid, C, previous child with spina bifida, D, hypertension, E, mutation in the methylene tetrahydrofolate reductase gene, hypertension, has seen no connection of maternal or paternal hypertension to spina bifida, there is an increased risk in women with obesity and diabetes, use of anti-seizure medications, and a mutation in the MTHR reductase gene, both will cause a folate deficiency, which is a greater risk for developing a neural tube defect. Looking at the epidemiology of spina bifida, it's the second most common disability of childhood. The incidence is one to three children per 10,000 births in the United States. It is variable within countries and regions. It's higher in China, Ireland, England, Pakistan, India, and Egypt, where it can be as high as three to seven out of 1,000, and it's lowest in Japan. We see more females than males at a 1.2 to 1 ratio. Prenatal screening is paramount in detecting neural tube defects and related disorders. Women receive the quad screen, where an elevated alpha-fetal protein can indicate a neural tube defect. A neural tube defect can also be visualized on routine ultrasound at 18 to 22 weeks. An ultrasound can determine the spinal level of the defect by localizing the vertebral arch defects. and examining the lower extremity function. Identify foot deformities as well. If there are abnormal labs or ultrasound and amniocentesis or high resolution ultrasound may be warranted. On fetal ultrasound, you'll visualize the vertebral defects on the spinal view. You can see a vertebral defect in a longitudinal view, 75% of which are located in the lumbosacral area. In this view, you can also see a u-shaped vertebral body with tissue protruding on transverse view as visualized in the pictures on the right. Looking at a cranial view, there are certain signs that can indicate hydrocephalus concerning for a neural tube defect. The banana sign where the cerebellar vermis herniates to the foramen magnum can be seen on the right side of the screen, and a lemon sign indicating frontal bossing can be seen on the left side of this fetal ultrasound image. After a diagnosis of myelomeningocele is made, a consult with neurosurgery follows. There is both closure after birth and in utero closure. The MOMS trial or management of myelomeningocele trial has shown improved motor outcomes with in utero closure. This also showed that severity of the chiari malformation was decreased and need for shunting was decreased. However, it's also showed an increased incidence of children born premature and uterine dehiscence due to the in utero surgery. A follow-up study at 30 months showed the prenatal repair improves mental development and motor function in the MOMS 2 trial. Prenatal consultation should include a compassionate and realistic discussion about the medical needs and functional prognosis for the child. The surgical and anatomical level is less predictive of functional outcomes compared to the functional level determined by physical exam and observation. Spina bifida is a lower motor neuron process. However, upper motor neuron signs can be seen with involvement of the spinal cord or brain with common comorbidities such as the Arnold Chiari 2 malformation, bleeding from shunt revisions, searings, tethered cord release, or others. Myelomeningocele will have an asymmetric and patchy distribution of motor and sensory deficits, but below the functional level the areas are weaker with decreased or absent sensation. Predicting embolation in a child with spina bifida requires looking at multiple factors, functional neurologic level, balance and coordination, weight, strength, visual abilities, and cognition. Other CNS complications and medical complications including fractures or procedures like urological surgeries or hospital stays may lead to weakness and gait impairments. Children are thought to achieve maximum ambulatory abilities by age 9. This is the age where they have optimized their strength and coordination, yet have not developed bigger adult-sized bodies and increasing weight to carry on decreasing leg strength.

Spina bifida

neural tube defect

myelomeningocele

spina bifida occulta

meningocele