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

 All rights reserved 2017 © anesthesiaconsiderations.com

 Feedback & inquiries: