spina bifida

Spina Bifida / Split spine

Spina Bifida is neural tube defect in which incomplete closure of vertebrae and neural tube.

Birth defect that occurs when spine and spinal cord doesn't form properly.

Etiology

1. Genetic

Child of parents with Spina Bifida.

2. Maternal age

Pregnant mother over 35 years of age or below 20 years of age.

3. Environmental

Radiants

4. Diet

Folic acid deficiency in pregnant mother.

5. Intake of epileptic medication during pregnancy.

Classification of Spina Bifida

1. Spina Bifida Occulta

2. Spina Bifida Cystica 

a. Meningocele 

b. Meningomyelocele/Myelomeningocele

1. Spinal Bifida Occulta

Small gap in spinal but no opening or sac on back. Spinal cord and meninges and nerve usually are normal.

Defect which result from failure of formation of bony arch around spinal cord.

2. Spina Bifida Cystica

Defect in closure of posterior vertebral arch with protrusion of spinal cord and meninges through defect.

a. Meningocele

Sac- like protrusion from spinal column. Containing meninges and cerebrospinal fluid but doesn't contain neural tissue.

Covering of sac with skin or with meninges.

b. Myelomeningocele/Meningomyelocele 

Sac-like protrusion of spinal cord and containing nerve tissue, CSF and meninges through spinal Defect.

Pathophysiology

The neural plate appear in the 17th day of gestation as thickening of the embryonic ectoderm.

On day 18 neural plate folds along midline.

By the end of third gestational week, the neural folds fuse to form Neural tube.

Fusion begins at Hindi brain - cervical junction first

Then anterior and posterior tube ends (Neuropores) closes to form spinal cord.

Neural canal becomes ventricles and central canal of spinal cord.

Vertebral column formed simultaneously with neural tube.

The end of neural tube close by end of 4th week of gestation.

Depending on the point of interruption on Neural tube formation develops NTDs may affect the brain (anencephaly) or spinal cord (spinal Bifida).

Clinical features

1. Spinal Bifida Occulta

a. Growth of hair over malformed vertebrae

b. Dimpling of skin secral area

2. Spina Bifida Cystica

a. Meningocele

1. External cyst Defect seen in back, sac composed only meninges and filled with CSF. Spinal cord and nerves tissue are normal.

2. Weakness of leg

3. Lack of sphincter control (loss of bladder and bowel control).

b. Myelomeningocele

1. Round raised, herniated mass present over vertebral column mainly lumbersacral regions, containing spinal nerves tissues, CSF, meninges.

2. Hydrocephalus; associated due to Arnold- chiari syndrome.

3. Loss of motor control and sensation occurs below level of lesions.

4. Fecal and urinary incontinence

5. Loss of bladder and bowel control

6. Urinary tract infection

7. Abnormal feet and leg such as club foot, developmental dysplasia of hip, kyphosis, scoliosis, resulting backpain, respiratory distress, difficulty in movement.

8. Developmental delay- speech, mobility.

Diagnostic Evaluation

1. Prenatal diagnosis of neural tube defect

Ultrasound

Fetal MRI

Amniocentesis - Increase level of alpha-feto protein (AFP) - test done 14th - 16th week of gestation).

2. Diagnosis after Birth

On neonatal examination - sac seen on back of baby

Trans-illumination test - shining light through baby sac, if sac become translucent it meningocele and if sac doesn't become translucent it meningomyelocele.

3. CT scan and MRI of spinal cord and brain

Determine bony deformities and spinal cord herniation, diagnosing presence of Hydrocephalus.

4. Urine test - presence of infection

5. Renal function test

6. WBC count, ESR test

7. Neurological assessment for motor response and sensory reaction.

8. Developmental assessment to detect and delay in milestones.

Management

1. For Spina Bifida Cystica surgery required.

Laminectomy and closure of defect or removal of sac done with in 24-48 hours of birth.

2. T- closure of skin graft done.

Nursing management

1. Prevention of infection

2. Preventing injury to sac

3. Preventing urinary track infection

4. Preventing hip and leg deformities

5. Preventing of skin breakdown

6. Provision of adequate nutrition

Complication

1. Hydrocephalus

2. Loss of bladder and bowel control

3. Meningitis

5. Frequentl UTI

6. Parmanent weakness or paralysis of leg

Prevention

1. Genetic counseling

2. In case of severe defect - detected in early pregnancy; therapeutic abortion

3. Folic acid suppliment - folic acid suppliment taken by women prior to conception.

Pregnant women need 1mg folic acid daily.