neurosurgical considerations in spina bifida debbie k. song, m.d. gillette children’s specialty...

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

DEBBIEKSONG@GILLETTECHILDRENS.COM