Most congenital spinal pathologies affect the upper cervical or lumbar regions:

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  Due to defective spina cord embryogenesis and/or vertebral malformation.

Neural tube defect (NTD):

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  Incomplete fusion of the neural tube during fetal development.

  
  
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  Myelodysplasia is the most common type of NTD:

  
  
  
  
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    These include spina bifida occulta, meningocele, myelomeningocele, and rachischisis.

Spine bifida affects approximately 1,500 births annually in the United States:

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  Highest rates of NTDs are found in China, Ireland, Great Britain, Pakistan, India, and Egypt.

Background and etiology:

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  Incomplete closure of the caudal end of the neural tube during spinal cord development and lack of fusion of vertebral arches:

  
  
  
  
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    Development of the vertebrae and spinal column begin in the third week of embryonic development.

    
    
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    The neural tube is created by the inward folding and fusing of the neural plate (primary neurulation).

    
    
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    Neural tube is the embryo’s precursor to the central nervous system.

  
  
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  Results in an open lesion or sac (spina bifida cystica) that can contain the spinal cord, nerve roots, and meninges:

  
  
  
  
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    Varying degrees of myelodysplasia depending on level of failed closure.

  
  
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  Environmental causes:

  
  
  
  
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    Maternal folic acid deficiency.

    
    
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    Maternal use of folic acid antagonists (dihydrofolate reductase inhibitors): aminopterin, methotrexate, sulfasalazine, pyrimethamine, triamterene, and trimethoprim.

    
    
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    Antiepileptic drugs: carbamazepine, valproate, phenytoin, primidone, and phenobarbital.

    
    
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    Maternal hyperthermia.

    
    
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    Maternal diabetes.

Types of myelodysplasia:

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  Spina bifida occulta:

  
  
  
  
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    Mildest form.

    
    
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    Unfused vertebral arch.

    
    
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    Meninges do not herniate through the opening in the spinal canal.

  
  
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  Meningocele:

  
  
  
  
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    A subset of spina bifida cystica:

    
    
    
    
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      Spinal elements are contained within a sac.

    
    
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    Herniation of the meninges (excluding the spinal cord), through the opening in the spinal canal.

  
  
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  Myelomeningocele:

  
  
  
  
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    A subset of spina bifida cystica.

    
    
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    Herniation of the meninges and the spinal cord through the opening in the spinal canal.

  
  
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  Rachischisis:

  
  
  
  
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    Neural elements exposed with no covering.

Presentation:

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  Mild forms (i.e., spina bifida occulta) may be asymptomatic:

  
  
  
  
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    Occasional abnormal tuft of hair or small dimple at the site of the spinal malformation.

  
  
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  Meningocele or myelomeningocele will present with a cyst containing neural elements.

  
  
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  Neurological symptoms can include bladder, motor, and sensory paralysis below the level of the spinal lesion.

  
  
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  Often associated with latex allergy.

  
  
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  Functional status is primarily related to the level of the defect ( Table 16.1 ):

  
  
  
  
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    Deformities that occur in patients with myelomeningocele are secondary to unbalanced/asymmetric muscle action around joints, paralysis, and decreased sensation in the lower extremities.

    
    
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    Lesion of L3 or above are mostly confined to a wheelchair.

  
  
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  Changes in functional level should alert the physician to the possibility of tethered cord syndrome:

  
  
  
  
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    Formation of fibrous attachments between the spinal cord and spinal canal:

    
    
    
    
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      Results in stretching of the spinal cord and progressive cord damage and neurologic deficit.

Clinical evaluation:

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  Examination should include assessment of level and degree of motor and sensory function, range of motion (ROM), spinal deformity, integrity of the skin, and associated deformities and contractures.

  
  
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  Prenatal laboratory diagnosis:

  
  
  
  
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    Maternal screening of serum alpha fetoprotein (AFP) levels:

    
    
    
    
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      Performed ideally at 16 to 18 weeks of gestation, but can be performed as early as 15 weeks or as late as 20 weeks.

      
      
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      First trimester screening is not recommended because of low sensitivity.

  
  
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  Magnetic resonance imaging (MRI) or computed tomography (CT) may be performed to get a more precise understanding of the underlying defect ( Fig. 16.1 ):

  
  
  
  
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    Dysplasia of the spinal cord and nerve roots may lead to bowel, bladder, motor, and sensory paralysis below the level of the lesion.

Treatment and prevention:

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  Maternal consumption of 0.4 mg (400 µg) of folic acid a day for ≥3 months before conception, decrease the chance of NTD by 70 to 80%.

  
  
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  Aim of treatment is to enable the child to reach the highest degree of strength, function, and independence:

  
  
  
  
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    Spina bifida occulta:

    
    
    
    
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      Patients usually do not need surgery.

      
      
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      Conservative management and watchful monitoring is recommended.

    
    
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    Meningocele:

    
    
    
    
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      Surgical treatment for the removal of the cyst is typically recommended.

      
      
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      If later orthopedic surgical intervention is necessary, it usually focuses on balancing of the muscles and correction of deformities.

    
    
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    Myelomeningocele and rachischisis:

    
    
    
    
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      Early treatment with antibiotics is necessary in order to prevent infection of the spinal cord.

      
      
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      Requires surgery within the first few days of life to correct the spinal defect and prevent infection and further injury to the exposed spinal cord/nerve roots.

      
      
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      Most common complications with surgery are tethered spinal cord and hydrocephalus.

      
      
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      In utero surgical intervention may be considered.