Spina Bifida (Myelomeningocele) Flashcards
Description
Failure of fusion of the neural fold
During neurulation phase of embryonic development
Embryologic defect of bone, meninges, and spinal cord
Spectrum from anencepahly to spina bifida occulta
Etiology
Multifactorial
Folate deficiency?
Environmental: socioeconomic, maternal age, hyperthermia, teratogens, seasonal
Familial
Incidence
0.6/1000 in US
Prenatal diagnosis
High incidence of Arnold Chiari II
Consists of downward displacement of the cerebellar tonsils through the foramen magnum (opening at the base of the skull)
As a result of obstruction, non-communicating hydrocephalus can result
Hydrocephalus
Abnormal accumulation of CSF in the ventricles of the brain
Causes increased intracranial pressure
In non communicating, due to obstruction of CSF outflow
Can cause headaches, dizziness, impaired coordination, and in severe cases, paralysis
Shunt hydrocephalus
in 90%
50% obstruct and require revision in 1st year of life
Risk of shunt infection 12%
Other Symptoms
Neurogenic bladder and bowel
Site of Defect, Percentages
Cervical level 1%
Upper Thoracic 1%
Lower Thoracic and Upper Lumbar 6%
Mid Lumbar 27%
Lumbosacral 42%
Sacral 21%
Entire lumbosacral 2%
Neurologic Impairment, Percentages
Cervical and upper thoracic 1%
Lower thoracic 27%
Intact hip flexion but impaired quadriceps 23%
Lower lumbar and quadriceps sparing 45%
Lower sacral, leg strength, B&B abnormal 4%
Neurological impairment
Typically flaccid paralysis
May have
Spasticity
Mixed paraplegia and spasticity
Asymmetry
Intact regions of voluntary control below regions of paralysis
Hydromyelia
50-80%
abnormal widening of the central canal of the spinal cord
Creates cavity in which cerebrospinal fluid can accumulate
Build up of CSF can put pressure on spinal cord
Damage nerve cells
Weakness of upper limbs, spasticity, ascending motor changes
Scoliosis
Tethered cord
11-15%
Traction of conus medullaris and cauda equina after repair
Progressive neurologic deficits
Impair strength, spasticity, back pain, B&B changes, scoliosis
May require surgical release
Musculoskeletal deformity of the hip
Occurs in majority
Hip Extensors and Abductors most affected
Muscle imbalance leads to hip flexion contracture
50% subluxed or dislocated hips
May require surgery
Musculoskeletal deformity of the knee
Flexion contracture most common
May be due to joint stiffness, spasticity in the knee flexors
Or Progressive crouched posture with weak quadriceps
More common L3 or higher
Musculoskeletal deformity of the foot
Deformities occur in 85%
Abnormal bony cartilaginous growth
Lack of sensation and vasomotor instability
- skin injury and poor healing
Equinovarus
Pure Equinus
Pes Cavus
Cock-up toe deformity at great toe
May require surgery as well as bracing