Anesthesia Considerations 

Spina Bifida

 

 

Background 

 

• Failure of the developing spine to completely enclose the neural elements in a bony canal

• May be associated with Chiari II malformation

• Spina bifida occulta:

  • Failed fusion of the neural arch without herniation of the meninges or neural elements

  • Defect limited to a single vertebra (typically L5 or S1)

  • Very common (5% to 36% of the population), can be considered a normal variant

• Spina bifida cystica:

  • Failed closure of the neural arch with herniation of the meninges (i.e., meningocele) or the meninges & neural elements (i.e., myelomeningocele) through the vertebral defect

• Myelomeningocele:

  • Progressive neurologic disease that eventually produces orthopedic, neurologic & genitourinary complications

• Occult spinal dysraphism: 

  • Intermediate group of conditions wherein the bony defect is associated with one or more anomalies of the spinal cord, including: intraspinal lipomas, dermal sinus tracts, dermoid cysts, fibrous bands & diastematomyelia (split cord)

  • These lesions are differentiated from the more benign spina bifida occulta

  • May have no neurologic symptoms or may have minor sensory, motor & functional deficits of the lower limbs, bowel & bladder; they also may have orthopedic issues, such as scoliosis, limb pain & lower extremity abnormalities  

  • Patients with cord abnormalities have cutaneous stigmata in 50% of cases & 70% have tethered spinal cord

 

 

Considerations 

 

• Need for neuroimaging/detailed neurological history & physical exam prior to neuraxial anesthesia:

  • Look for hair tufts, dimples, hyperpigmented lesions, cutaneous lipomas over the spine & if present send for imaging prior to neuraxial or do GA only

• CNS: 

  • Hydrocephalus & risk of ↑ ICP, many have VP shunt 

  • Flaccid paralysis usually high lumbar/low thoracic

  • Potential for autonomic hyperreflexia if lesion between T5-T8 

  • Bowel & bladder control dysfunction

• Respiratory:

  • Scoliosis with restrictive lung disease, risk of pulmonary hypertension/RV failure 

• Cardiovascular: possible congenital heart disease 

• ↑ incidence of latex allergy

 

 

Pregnancy

 

• Spina bifida occulta:

  • Neuraxial is generally safe

  • Recommend to insert needle remote from site of malformation seen on imaging 

  • Patients are at higher risk of post dural puncture headache 

• Meningocele & myelomeningocele:

  • If spinal level involvement T11 or higher, likely will have painless labor 

  • Epidural & spinal has been performed in literature, so NOT absolute contraindication but will be difficult & may be unreliable 

• May need epidural in situ to avoid autonomic hyperreflexia during labour