Spina Bifida: Overview, Diagnosis, Treatment

Spina Bifida is a rare category of Neural Tube Defects where the spinal cord does not close or, in some extreme cases, even fails to properly develop. Though its causes are not specifically known, Folic Acid consumption has been significantly correlated with a higher risk of such conditions. Diabetes and certain medications (if taken during pregnancy) are also factors contributing to high risk pregnancies. 

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The 3 types of Spina Bifida that are commonly found are as follows:

1. Myelomeningocele- This is the most common, and unfortunately the most severe form of Spina Bifida where the portions of the spinal cord may push out and form a sac where the meninges and other protective portions are disrupted. This causes exposed tissue, nerves and possible CSF leaks can result in serious infections and other complications.This is the rarest form of Spina Bifida and nerves, spinal cord and other functioning is severely affected. This often results in lifelong disabilities, especially related to limb and bladder functioning. 

 

1. Meningocele- Meningocele involves a defect of the posterior elements of the spine with extrusion of meninges and cerebrospinal fluid (CSF) without the involvement of the neural elements. This is a milder form of Spina Bifida in which only the outermost meninges, or outer layers covering the Spinal Cord, are abnormally formed and do not close. A sac is more common in this form of Spina Bifida, which does not contain any neural tissue unlike Myelomeningocele malformations. The Spinal Cord remains intact. Only mild symptoms may be observed, including bowel and bladder movement difficulties.

 

1. Spina Bifida Occulta- This type of Spina Bifida is hidden, and is the mildest and most common form of the condition. It is often detected through imaging, and usually causes minor gaps in the vertebrae. No treatment is needed if there are no obvious neurological impairments. Complications like tethered cord syndrome may however require surgery (Mayo Clinic, n.d.).

DIAGNOSIS:

Prenatal diagnosis is most common for Myelomeningocele, for which Alpha-fetoprotein or AFP levels are extremely high in tests during the 2nd  or 3rd trimester of pregnancy. These types are usually detected immediately with examination of the protruding sacs in the case of Meningocele or open sacs for Myelomeningocele post natal. 
Post-natal diagnosis is unfortunately more common in areas with limited access to care, which is due to less prenatal testing and lower detection rates for Spina Bifida. This is especially true for Meningocele as stated previously because of its less obvious presentation on ultrasounds and AFP tests. The advancement of ultrasound technology has led to almost a 90% prenatal detection rate in the US specifically (Medscape, 2024).
The testing for Tethered Cord Syndrome is common practice for all Meningocele and Spina Bifida Occulta patients as even though the Spinal Cord is not always disoriented in these cases, it is important to confirm the absence of these complications. This condition occurs when the Spinal Cord becomes attached to the Spinal column or vertebrae, and this can be present in individuals with all forms of Spina Bifida- even though it is extremely rare for Spina Bifida Occulta (Spina Bifida Association, n.d., p. 1). These are more often detected through MRI or CT imaging after birth, in the instance that symptoms are observed.


MAJOR SYMPTOMS AND PRESENTATION:

    Spina Bifida can be detected using higher AFP levels as stated above, but also presents in the form of lesions, Arnold-Chiari malformation and ventriculomegaly. The Arnold-Chiari or Chiari II malformation is usually the first sign of Spina Bifida in ultrasounds, and is observed as compression of the Cerebellar Tonsils (at the base of the Cerebellum) or the Brainstem below it. Ventriculomegaly is another sign of the Chiari II malformation, which is the flattening or increased concavity of the frontal Cranial bones. All of these are indicative of increased intracranial pressure and the abnormal formation of the spinal cord extending from the Brainstem as development continues. 
After birth, the most common symptoms that lead to diagnosis include:

• Seizures- usually epileptic in nature
• Hydrocephalus (build-up of Cerebrospinal Fluid in the Brain)
• Urinary and Bowel issues (usually incontinence)
• Weakness or paralysis in limbs
• Abnormal spine curvature or limbs
• Skin cysts (prominent, used to diagnose Spina Bifida Occulta)

(Sivarajah, Relph, Sabaratnam, & Bakalis, 2019)



GENERAL TREATMENT:

Treatments in the foetal stage usually include foetal surgery before the 26th week of pregnancy, which reduces risks of complications in the later stages of development, especially that of hydrocephalus. 
Postnatal treatment involves immediate surgery within 72 hours for Myelomeningocele, but can be delayed on a case-by-case basis for less advanced Spina Bifida. Shunts for hydrocephalus and additional care for motor difficulties is also required for many (Mayo Clinic, n.d.).

OTHER CONSIDERATIONS:
 
There are multiple risk factors and diagnosis plans that are unique to each case, as Spina Bifida does not have a significant correlation with a single gene or epigenetic factor. A series of genes and preconception considerations govern the likelihood of a fetus with Spina Bifida, and incredibly complex symptoms of urinary and bowel dysfunctions, as well as some “hidden,” mild symptoms make diagnosis especially difficult. Awareness regarding the “Banana Sign” associated with the compressing of the cerebellum parts and the “Lemon sign” associated with frontal cranial bones, as well as amniocentesis to diagnose other genetic abnormalities have certainly increased likelihood of timely care (Spina Bifida Association, n.d., p. 1). 


REFERENCES            
                    
Mayo Clinic. (n.d.). Spina bifida - Diagnosis and treatment. Mayo Clinic. 
https://www.mayoclinic.org/diseases-conditions/spina-bifida/diagnosis-treatme
nt/drc-20377865

Mayo Clinic. (n.d.). Spina bifida: Symptoms and causes. Retrieved from 
https://www.mayoclinic.org/diseases-conditions/spina-bifida/symptoms-causes/
syc-20377860#:~:text=Overview,the%20tissues%20that%20enclose%20them

Medscape. (2024, October 30). Spina bifida: Clinical presentation. Retrieved 
December 29, 2024, from 
https://emedicine.medscape.com/article/311113-clinical?form=fpf

Sivarajah, K., Relph, S., Sabaratnam, R., & Bakalis, S. (2019). Spina bifida in 
pregnancy: A review of the evidence for preconception, antenatal, intrapartum 
and postpartum care. Obstetric medicine, 12(1), 14–21. 
https://doi.org/10.1177/1753495X18769221 

Spina Bifida Association. (n.d.). Spinal cord tethering [PDF]. 
https://www.spinabifidaassociation.org/wp-content/uploads/Spinal-Cord-Tetheri
ng1.pdf

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