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Spina bifida

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Contents

Introduction

Spina Bifida (SB) refers to any birth defect involving incomplete closure of the spine, such as an incomplete spinal arch. Spina Bifida is a neural tube defect (NTD)(Salter, 1999). The neural tube defect typically develops during the first month of gestation within the mother's womb. SB is commonly seen near the lumbar and sacral vertebrae and less commonly in thoracic vertebrae. SB can cause physical and or mental disabilities ranging from mild conditions to severe in the affected individual. Severity of a condition is dependent upon the size and location of the opening in the spine and if the spinal cord and nerves are affected.


Types

Graphic representation of Myelomenigocele and Meningocele   Photo Courtesy of http://www.nlm.nih.gov/medlineplus/ency/imagepages/19086.htm
Graphic representation of Myelomenigocele and Meningocele Photo Courtesy of http://www.nlm.nih.gov/medlineplus/ency/imagepages/19086.htm

The three types of Spina Bifida include Spina Bifida Occulta, Meningocele, and Myelomeningocele (Spina Bifida Cystica). Spina bifida occulta is a condition in which the vertebrae do not close but the spinal cord and meninges remain in place, and skin usually covers the defect. Spina bifida occulta is the least harmful form, and often goes undetected. The condition is asymptomatic and the spinal cord and nerves go unharmed. Individuals typically become aware of their condition after having a radiograph of their spine, and a physician points out the vertebral defect. Meningocele is a condition where the tissue covering the spinal cord sticks out of the spinal defect but the spinal cord remains in place. In meningocele, a sac of fluid protrudes out of the back. The spinal cord is not located within this protrusion, and there is little or no nerve damage. The protrusion can cause minor disabilities and be associated with some deformity of the spine.

Myelomeningocele is the protrusion of the spinal cord and it’s covering through a defect in the vertebrae. Myelomeningocele is the most serious type of Spina Bifida. It accounts for greater than 90% of SB cases (Au K, 2010). Myelomeningocele causes nerve damage and disabilities. Myelomeningocele leads to partial or complete flaccid paralysis and total sensory impairment of all structures innervated below level of the neurological lesion(Lusardi, 2007).


Causes

The cause of Spina Bifida is unknown, but genetic and environmental factors appear to have contributing factors in developing SB. Low levels of folic acid in a woman's body before and during early pregnancy play a part in this birth defect. The vitamin folic acid (or folate) is important for brain and spinal cord development. 50-70% of NTD can be prevented through daily consumption of .4 mg of folic acid daily (Boulet, 2009), and recommended dosage of 1mg daily for pregnant women.


Incidence and Prevalence

In 2005, the prevalence of SB in the United States was two in 10,000 live births (Au et al 2010). Myelomeningocele may affect as many as 1 out of every 800 infants (National Institute of Health, [1]). More than 4500 pregnancies in the European Union and 3000 in the USA each year are affected by neural tube defects (Oakeshott 2010). The worldwide incidence of neural tube defects ranges from 1 to 10 of every 1000 births with equal frequency between spina bifida and anencephaly (Au et al 2010).


Signs & Symptoms

  • Hair at the back part of the pelvis in the sacral area
  • Dimpling or bump of the sacral area (gibbus)
  • Partial or complete lack of sensation
  • Partial or complete paralysis of the legs
  • Weakness of the hips, legs, or feet
  • Arnold Chiari Malformation - http://www.ninds.nih.gov/disorders/chiari/chiari.htm
  • Build up of fluid inside the skull (hydrocephalus)
  • Loss of bladder or bowel control
  • Scoliosis
  • Mental Retardation
  • Abnormal feet or legs, such as clubfoot


Medical Management & Treatment

Treatment of Spina Bifida varies depending on the extent of neural damage, and the complications associated with the neural tube defect. The most urgent treatment is typically required in order to protect the spinal cord and nerves. A child with myelomeningocele is usually operated on within two to three days of birth to treat the gibbus. This prevents infections and can save the spinal cord from more damage. Children with hydrocephalus may need a shunt inserted to drain extra fluid from their brain. Antibiotics may be administered to prevent or treat meningitis or urinary tract infections. Other treatment goals may include, but are not limited to:

  • correct or prevent deformity and contractures
  • Assist upright posture
  • Obtain locomotor function
  • Improve gait efficiency
  • Maintain joint positioning
  • Protect insensate areas

(Salter, 1999) and (Lusardi, 2007)


References

  • Au, K. S., Ashley-Koch, A. and Northrup, H. Epidemiologic and genetic aspects of spina bifida and other neural tube defects. Developmental Disabilities Research Reviews, 2010; 16: 6–15.
  • Boulet SL, Gambrell D, Shin MS, et al. (2009). Racial/ethnic differences in the birth prevalence of spina bifida-United States , 1995-2005. MMWR Morb Mortal Wkly Rep. 2009 Jan 9;57(53):1409-13.
  • Lusardi M.M., Nielsen C.C. (2007). Orthotics and Prosthetics in Rehabilitation. St. Louis, Missouri; Mosby Elsevier.
  • National Institutes of Health. http://www.nih.gov Accessed on December 4, 2011.
  • Oakeshott, P., Hunt, G., Poulton, A., & Reid, F. (2010). Expectation of life and unexpected death in open spina bifida: a 40-year complete, non-selective, longitudinal cohort study. Developmental Medicine And Child Neurology, 52(8), 749-753.
  • Salter, R.B.(1999). Textbook of Disorders and Injuries of the Musculoskeletal System. Baltimore, Maryland; Lippincott Williams & Wilkins.


External Links

To learn more about Spina Bifida refer to the Spina Bifida Association.