Neural Tube DefectsNeural Tube Defects

By : Dr . Ashraf SHAKER By : Dr . Ashraf SHAKER Lecturer of Neurosurgery Lecturer of Neurosurgery

When do neural tube defects occur?When do neural tube defects occur?

Neural Tube Neural Tube DevelopmentDevelopment

Normal embryological Normal embryological development development Neural plate Neural plate

development -18th daydevelopment -18th dayCranial closure 24th Cranial closure 24th

day (upper spine)day (upper spine)Caudal closure 26th Caudal closure 26th

day (lower spine)day (lower spine)

What is Spina Bifida?What is Spina Bifida?

A midline defect of the A midline defect of the bone, bone, skin, skin, spinal column, &/orspinal column, &/orspinal cord.spinal cord.

Clinical ConsiderationsClinical Considerations

Does the Does the mother mother generally generally know she is know she is pregnant pregnant when the when the neural tube neural tube is is developing?developing?

(See Tecklin, (See Tecklin, page 166.)page 166.)

Note this chart illustrates WEEKS of gestation (pregnancy).Note this chart illustrates WEEKS of gestation (pregnancy).

Clinical considerations:Clinical considerations:At what point could health professionals prevent At what point could health professionals prevent

the development of neural tube defects? the development of neural tube defects?

(See Tecklin, page166.)(See Tecklin, page166.)

Consider the role of the PT in health promotion Consider the role of the PT in health promotion and prevention through education. and prevention through education.

Preventive CarePreventive Care

• TThe United States Public Health Service he United States Public Health Service recommends that: "recommends that: "All women of All women of childbearing age in the United States childbearing age in the United States who are capable of becoming pregnantwho are capable of becoming pregnant should consume 0.4 mg of folic acid per day should consume 0.4 mg of folic acid per day for the purpose of reducing their risk of having for the purpose of reducing their risk of having a pregnancy affected with spina bifida or other a pregnancy affected with spina bifida or other neural tube defects." Folic acid is a "B" vitamin neural tube defects." Folic acid is a "B" vitamin that can be found in such foods as: cereals, that can be found in such foods as: cereals, broccoli, spinach, corn and others, and also as broccoli, spinach, corn and others, and also as a vitamin supplement.a vitamin supplement.

Types of Myelodysplasia*Types of Myelodysplasia*

• Spina bifida occultaSpina bifida occulta

• LipomeningoceleLipomeningocele

• MeningoceleMeningocele

• Myelomeningocele = Spina BifidaMyelomeningocele = Spina Bifida

**defective development of the spinal corddefective development of the spinal cord

Neurologic pathologyNeurologic pathology

Spina bifida Spina bifida occulta occulta

((occultaocculta = closed) = closed)

A condition A condition involving involving nonfusion of the nonfusion of the halves of the halves of the vertebral arches vertebral arches without without disturbance of disturbance of the underlying the underlying neural tissueneural tissue

Neurologic pathologyNeurologic pathology

LipomeningoceleLipomeningocele

((lipo lipo = fat)= fat)

lipoma or fatty lipoma or fatty tumor located tumor located over the over the lumbosacral lumbosacral spine. Associated spine. Associated with bowel & with bowel & bladder bladder dysfunctiondysfunction

LipomeningoceleLipomeningocele

Neurologic pathologyNeurologic pathology

Meningocele (Meningocele (celecele = sac) = sac)

Fluid-filled sac with meninges involved but neural Fluid-filled sac with meninges involved but neural tissue unaffectedtissue unaffected

Types of MyelodysplasiaTypes of Myelodysplasia

MyelomeningoceleMyelomeningocele

or or spina bifidaspina bifida: : meninges and spinal meninges and spinal tissue protruding tissue protruding through a dorsal through a dorsal defect in the defect in the vertebraevertebrae

The spinal defect with The spinal defect with myelomeningocelemyelomeningocele

Incidence and PrevalenceIncidence and Prevalence

• Incidence Incidence – 1/10001/1000

• Prevalence Prevalence – Increased incidence in families of Celtic and Increased incidence in families of Celtic and

Irish heritage (genetic or environmental?)Irish heritage (genetic or environmental?)– Increased incidence in minorities (genetic or Increased incidence in minorities (genetic or

environmental?)environmental?)– Increased incidence in familiesIncreased incidence in families

EtiologyEtiology

Neural Tube defects may result from:Neural Tube defects may result from:• Combination of environmental and Combination of environmental and

genetic causesgenetic causes• Teratogens – Teratogens – Remember what these Remember what these

are?are?• Nutritional deficiencies - notably, folic Nutritional deficiencies - notably, folic

acid deficiencyacid deficiency

Diagnosis and DetectionDiagnosis and Detection

AmniocentesisAmniocentesisAFP - indication of abnormal leakageAFP - indication of abnormal leakage

Blood testBlood testMaternal blood samples of AFPMaternal blood samples of AFP

UltrasonographyUltrasonographyFor locating back lesion vs. cranial signsFor locating back lesion vs. cranial signs(See Tecklin, pages 167-168.)(See Tecklin, pages 167-168.)

PrognosisPrognosis

Spina bifida is a:Spina bifida is a:static static non-progressive defect non-progressive defect with with worseningworsening from secondary problems. from secondary problems.The prognosis for a normal life span is generally The prognosis for a normal life span is generally

good for a child with good health habits and a good for a child with good health habits and a supportive family/caregiver.supportive family/caregiver.

Impairments associated with Spina Impairments associated with Spina BifidaBifida

Physiological changes below the level of the Physiological changes below the level of the lesion generally include:lesion generally include:

abnormal nerve conduction, resulting in:abnormal nerve conduction, resulting in:somatosensory lossessomatosensory lossesmotor paralysis, including loss of bowel and motor paralysis, including loss of bowel and

bladder controlbladder control

Impairments associated with Spina Impairments associated with Spina BifidaBifida

Physiological changes below the level of the lesion Physiological changes below the level of the lesion generally include:generally include:

abnormal nerve conduction, resulting in:abnormal nerve conduction, resulting in:

changes in muscle tone* changes in muscle tone*

*Note: Muscle tone can range from flaccid to normal *Note: Muscle tone can range from flaccid to normal to spastic; may have UMN signs with/without true to spastic; may have UMN signs with/without true spastic paraparesis; progression of neurologic spastic paraparesis; progression of neurologic dysfunction or change in neurologic status most dysfunction or change in neurologic status most concerningconcerning

Impairments associated with Impairments associated with Spina BifidaSpina Bifida

Anatomical changes below the level of Anatomical changes below the level of lesion: lesion:

musculoskeletal deformities (scoliosis)musculoskeletal deformities (scoliosis) joint and extremity deformities (joint contractures, joint and extremity deformities (joint contractures,

club foot, hip subluxations, diminished growth of club foot, hip subluxations, diminished growth of non-weight bearing limbs)non-weight bearing limbs)

osteoporosis osteoporosis abnormal or damaged nerve tissueabnormal or damaged nerve tissue

Impairments associated with Impairments associated with Spina BifidaSpina Bifida

Anatomical changes associated with a cervical lesion:

An enlarged head caused by hydrocephalus

(“water on the brain” Hydrocephalus

Arnold Chiari MalformationArnold Chiari Malformation

Arnold Chiari type II Arnold Chiari type II Malformation: Malformation:

cerebellar hypoplasia cerebellar hypoplasia ((hypoplasiahypoplasia = reduced = reduced growth)growth)

with caudal displacement with caudal displacement of the hindbrain through of the hindbrain through the foramen magnum the foramen magnum

usually associated with usually associated with hydrocephalushydrocephalus