Spina BifidaAmaan Mohiuddin

Gary Oh

CaseNewborn infant in the

labor and delivery room

Physical examVital signs normalAppearance

Bulging cyst-like structure approximately 4 cm in diameter protruding from his back.

Child has limited movement of the lower extremities

Both feet are plantarflexed and inverted at the ankle

What is it?“Cleft spine,” is characterized

by the incomplete development of the brain, spinal cord, and/or meninges.

Neural Tube DefectFailure to close during 4th

week embryogenesis

SymptomsLeg paralysis

Incontinence

Anaesthesia

Hip, knee, feet abnormalities

Hydrocephalus

Arnold-Chiari Type II

Physical ExamInspection (Back):

Tuft of hair, subcutaneous lipoma or dimple may be observed in occulta

Localised sac in cystic type, increased head size

Deformity of lower limb as flexion: Abduction and internal rotation of hipFlexion or hyper extension kneeEquinous or calcanous deformity of foot,Scoliosis or lordosis of spine

Skin ulceration and soft tissue injury due to pressure

Physical Exam(Cont)Palpation:

Bony defectSubcutaneous lipomaLoss of sensation and muscle bulk

ScreeningMyelomeningocele can be diagnosed in second

trimester of pregnancy

Increased maternal serum alpha-fetoprotein (MSAFP) Check at 15-20 weeks if maternal age > 35

yearsPrior child with open neural tube defect

Amniocentesis at 14-18 weeksRoutine second-trimester ultrasound might be

more sensitive than MSAFP alone for detecting neural tube defects

Screening (Cont)Imaging

Spinal X-rayUSMRI

Dysraphism – incomplete closure of bony ring or vertebrae surround neural tube (spinal cord)

Spina bifida occulta Mildest form of spina bifida Abnormal opening of spine, may have dimple on skin,

tuft of hair or nothing Small defect in one or more vertebrae, usually no

complications Outer part of some vertebrae not completely closed The split in the vertebrae is so small that the spinal

cord does not protrude The condition is asymptomatic Bony abnormality seen by X–ray

Classification

Classification (Cont)Meningocele

Spinal defect with cyst of membranes protruding through spine

Vertebral arches are unfusedHerniation of the meningesCorrective surgery can be done

MyelomeningoceleSpinal defect with cyst including membranes,

nerve roots and possibly spinal cord protruding through spinal opening.

The spinal cord fails to develop properly and nerves are damaged

CauseScientists suspect genetic, nutritional,

and environmental factors play a role

Folic acid deficiencies from lack of intake before and during pregnancy have shown to be a cause

 The Folate Metabolism Pathway is suspected to be a major contributor

IncidenceMost common severe birth defects in the

United States

1,500 to 2,000 babies (one in every 2,000 live births) each year

1970 to 1977: In US, incidence of spina bifida decreased 6.7%/year, before folic acidsupplementation was prevalent

1996: The US FDA authorized all enriched grain products be fortified with folic acid

PrevalenceDecreased prevalence of spina

bifida and anencephaly from 1995 to 2002 in United States (during period of transition to mandatory folic acid fortification)

Risk FactorsPROBABLE:

History of prior delivery of offspring with neural tube defect

Prenatal exposure to valproic acidMaternal diabetesMaternal obesity

 POSSIBLE:Maternal peri-conceptional opioid useLower vitamin B12 levels during pregnancyAntimalarial drugs during first trimesterChronic low-dose radiation exposure

Associated ConditionsDermal sinus tract

Diastematomyelia (splitting of cord into half)

TreatmentPrenatal surgery for myelomeningocele

reduces need for shunt placement compared to postnatal repair

Primary surgical closure of defect to prevent infection in more severe casesOften hydrocephalus develops due to

associated Arnold-Chiari malformation, shunting may be necessary

ComplicationsMental retardation and seizures with

hydrocephalus

Neurologic deficits below lesion

Absent bladder control, recurrent urinary tract infections

Urinary diversion severe chronic constipation

Club foot

PrognosisImproved 1-year survival from 1979 to

2003

Worsening cerebellar herniation on MRI associated with increased risk of poor functional outcomes in fetuses with spina bifida

Perineal sensation in infancy predicts better prognosis in patients with open spina bifida

PreventionFolic acid fortification associated with reduction

in incidence of neural tube defects

Folic acid 0.4 mg/day around time of conception

4 mg/day if previous infant with neural tube defects

Peri-conceptional folate supplements associated with reduced frequency of neural tube defects in women with and without previously affected pregnancy

ReferencesDynamed: Spina BifidaObstet Gynecol 2005 Oct;106(4):747MMWR Morb Mortal Wkly Rep 1997 Dec 12;46(49):1171 full-text in Pediatric

Notes 1998 Jan 1;22(1):1Pediatrics 2005 Sep;116(3):580, editorial can be found in Pediatrics 2005

Sep;116(3):753, commentary can be found in Pediatrics 2006 Apr;117(4):1394

Cerebrospinal Fluid Res 2006 Aug 1;3:10 full-textObstet Gynecol 2013 Oct;122(4):838Pediatrics 2009 Mar;123(3):917Pediatr Neurosurg 2011;47(3):194 in J Neonat Surg 2012 Jul-Sep;1(3):43 PDFPediatrics 2010 Apr;125(4):e836Birth Defects Res A Clin Mol Teratol 2012 Oct;94(10):756Pediatric Surgery Update 2008 Jan;30(1):2Pediatric Surgery Update 1998 Apr;10(4):3Pediatrics 1998 Sep;102(3):e34BMC Pediatrics 2005 Aug 25;5:32J Pediatr 2012 Dec;161(6):1132Obstet Gynecol 2010 Aug;116(2 Pt 1):323Arch Dis Child 2007 Jan;92(1):67Cochrane Database Syst Rev 2010 Oct 6;(10):CD007950