neurosurgical considerations in spina bifida debbie k. song, m.d. gillette children’s specialty...
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Neurosurgical Considerations in Spina Bifida
Debbie K. Song, M.D.
Gillette Children’s Specialty Healthcare
St. Paul, MN
Spina Bifida Association of Iowa
Education Day 2015
March 28, 2015
Neurosurgical Issues in Spina Bifida
Spina bifida / myelomeningoceleClosure of myelomeningoceleHydrocephalusChiari II MalformationTethered Spinal CordSyringomyelia
Spina Bifida
Myelomeningocele Incidence: ~1-2/1000 live births Genetic risk
2-3% risk of having child with myelomenigocele after having a prior pregnancy affected by myelomeningocele
6-8% if 2 affected siblings Increased risk when close relatives have pregnancies affected by
myelomeningocele Risk factors
Prior pregnancy affected by myelomeningocele Maternal folic acid deficiency
0.4 mg/day if no history of neural tube defect 4 mg/day if prior pregnancy with neural tube defect
Pregestational maternal diabetes mellitus Certain antiseizure medications: valproic acid, carbemazepime
Myelomeningocele closure
Adzick NS et al, N Engl J Med. 2011 March 17; 364 (11):993-1004
Hydrocephalus
Hydrocephalus Affects 85% of people with myelomeningocele5-10% of babies with MMC have overt
hydrocephalus at birth If it occurs, hydrocephalus usually does so by 6
months of ageMay become clinically evident after closure of
back at birthShunt to treat hydrocephalus in myelomeningocele
Some work looking at endoscopic third ventriculostomy (ETV) as an alternative
Catheter in ventricle through burr hole in skull Reservoir/valve (separate or in combination) Distal catheter draining into:
Peritoneal cavity Pleural cavity Right atrium Gallbladder, sagittal sinus, fallopian tube…
Antibiotic impregnated catheter Anti-siphon devices Programmable valves
Shunts – basic configuration
Ventriculoperitoneal shunt for hydrocephalus
Neurosurgery follow-up important Why was the shunt placed? What kind of valve (programmable? Setting?) History of shunt surgeries – malfunctions, infections? What does child look like during a shunt malfunction? Copies of scans on file for local ER/future comparison Do ventricles get larger when shunt malfunctions?
Managing a child with hydrocephalus
Chiari II malformation
Chiari II malformation Present in 75-90% of patients with
myelomeningocele Constellation of anomalies:
Hindbrain herniation (downward displacement of parts of the medulla, cerebellum, 4th ventricle into spinal canal)
Brainstem abnormalities Low-lying venous sinuses Small posterior fossa
Chiari II related to hydrocephalus development Intrauterine repair of myelomeningocele
reduces incidence of Chiari II (MOMS trial)
Chiari II malformation Leading cause of mortality in infants with myelomeningocele 15-30% of patients symptomatic, requiring surgery Presentation in infants:
Apnea, swallowing problems, stridor, lower cranial neuropathies High-pitched, hoarse, weak cry Vocal cord palsy, hypotonia Recurrent aspiration pneumonia, nasal regurgitation
Presentation in older patients: Headache, neck pain Balance/coordination problems Increased upper extremity spasticity , weakness
Make sure shunt is working!
Tethered Spinal Cord
Tethered Spinal Cord
Everyone with repaired myelomeningocele will have radiographic tethered cord
~1/3 of patients with spina bifida will require tethered cord release surgery
Assess for symptoms: neurologic, orthopedic, urologic
Clinical symptoms often driven by growth spurt
Make sure shunt is working!
Syringomyelia
Syringomyelia CSF within the spinal cord Present in 40-80% of patients with myelomeningocele Symptomatic in 2-5% of patients; assess for clinical change! Presentation overlaps with tethered cord and Chiari II
symptoms: Upper extremity weakness, loss of function Hand deformity neck or back pain Worsening scoliosis Spasticity Ascending motor loss in the legs
Treatment options: syrinx shunt, Chiari decompression, tethered cord release
Make sure shunt is working!
Final Thoughts
Shunt care is important Clinical deterioration warrants investigation…starting
with shunt function Overall clinical picture is more important than imaging Be proactive and accountable for you/your child’s
healthcare