Spina bifida : diagnostic prénatal et suivi | Clinique Omicron
Classification - Clinical presentations
| Shape | Anatomy | Clinical presentation | Prognosis |
|---|---|---|---|
| Spina bifida occulta | Posterior arch bone defect (failure of vertebral lamina to close) + NORMAL spinal cord and meninges + intact skin covering the defect + most often L5-S1 | Asymptomatic in the majority of cases + incidental finding on X-ray + may manifest as a skin sign (tuft of hair + dimple + hemangioma + subcutaneous lipoma) on the dorsal midline | Excellent + no treatment needed unless neurological signs or tethered cord |
| Meningocele | Herniation of meninges (dura mater + arachnoid mater) through the bony defect → sac filled with CSF + spinal cord in NORMAL POSITION in the canal | Swollen mass + skin-covered + adjacent to the spine + little or no neurological deficit (spinal cord not involved in the sac) | After surgical repair + few neurological sequelae |
| Myelomeningocele (MMC) | La forme la plus sévère (90 % des spina bifidas ouverts) + herniation des méninges ET de la moelle épinière ou des racines nerveuses + sac recouvert partiellement ou non de peau + tissu neural exposé (placode) | Neurological deficit below the level of the lesion (paralysis + sensory disturbances + bladder-sphincter incontinence + intestinal disturbances) + Chiari II malformation (descent of the cerebellum + brainstem into the foramen magnum) in 90 % → hydrocephalus in 70–90 % | Variable depending on the level of the lesion + intensive lifelong multidisciplinary care |
| Myelocystocele (spina bifida) | Flattened spinal cord + completely open + exposed on the surface + without a sac + rarest and most severe form | Complete neurological deficit below the lesion level + very severe prognosis | Severe + often incompatible with independent living |
Prenatal screening
- Maternal serum alpha-fetoprotein (AFP): dosage between 15 and 20 weeks of amenorrhea (SA) → elevated AFP (> 2.5 MoM — multiples of the median) + suggests an open NTD (myelomeningocele or anencephaly) or another cause of neural tube or abdominal wall opening → 80-85% sensitivity % for open spina bifida
- 2nd trimester morphological ultrasound (18-22 weeks gestation): Reference examination + ultrasound signs: lemon sign (bilateral frontal deformation of the skull resembling a lemon due to cerebellar herniation) + banana sign (flattened cerebellum curved downwards due to Chiari II malformation) + posterior spinal defect + visible meningeal or neural sac + hydrocephalus (dilation of the cerebral ventricles) + sensitivity 95-99 % in specialized centers for open forms
- Fetal MRI complementary to ultrasound in difficult cases, specifies the lesion level, assesses the extent of spinal cord involvement, detects associated brain abnormalities
- Amniocentesis AFP in amniotic fluid + acetylcholinesterase (specific marker of exposed neural tissue) → confirmation if ultrasound is inconclusive
Complications associated with myelomeningocele
- Hydrocephalus (70–90 %) : Chiari II malformation → cerebrospinal fluid circulation obstruction → progressive ventricular dilation → macrocephaly + bulging fontanelle + irritability + vomiting → ventriculoperitoneal (VP) shunt or ventriculo-subarachnoid shunt + or endoscopic third ventriculostomy → regular cerebral ultrasound monitoring
- Chiari II Malformation descent of the cerebellar vermis + brainstem into the foramen magnum → compression → stridor + apnea + swallowing disorders + spastic tetraplegia + neurosurgical emergency if symptomatic → decompression of the craniocervical junction
- Tethered cord spinal cord scarring after initial surgery → progressive traction on the spinal cord with growth → neurological worsening (pain + weakness + sphincter dysfunction) → filum terminale transection surgery
- Motor and sensory deficits: lesion level determines extent → L3–L4: can walk with orthotics → L5: walking possible + L1–L2: paraplegia + wheelchair
- Bladder-sphincter dysfunction neurogenic bladder (retention + incontinence + recurrent urinary tract infections → risk of nephropathy) → clean intermittent catheterization (CIC) + antimuscarinics + regular urological monitoring + annual renal ultrasound
- Latex allergy prevalence of 20-65 % in children with spina bifida (repeated latex exposure during care from birth) → strict latex precautions in all care settings + alert bracelet
- Orthopedic problems foot deformities (clubfoot) + scoliosis + hip dislocation + arthrogryposis → regular orthopedic follow-up + bracing + orthopedic surgery as needed
Neonatal and long-term support
- Immediate neonatal care: Cover the sac with a moist, non-adherent sterile gauze pad + prone position (avoid pressure on the sac) + prophylactic antibiotics (ampicillin + gentamicin) + urgent neurosurgical assessment + closure surgery within 24–72 hours (ideally within 24 hours to reduce infectious risk + progression of neurological deficit)
- Multidisciplinary follow-up (spina bifida specialized clinic): neurosurgery + pediatric urology + orthopedics + physical medicine and rehabilitation + physical therapy + occupational therapy + speech therapy + psychology + social work + dietetics
- Transition to Adult Care: Major issue: Adolescents with spina bifida need to be supported in their transition to adult care (adult urology, neurology, orthopedics). Specialized transition clinics facilitate this crucial passage.
- Folic acid — prevention: woman of childbearing age without a history of NTDs: 0.4–0.8 mg/day ideally 3 months before and during the 1st trimester + woman with a history of pregnancy with NTDs + or on antiepileptics + or diabetes: 4–5 mg/day + flour fortification in Canada (since 1998) → 46% % reduction in the incidence of NTDs
All newborns with a mass overlying the spine and an area of skin breakdown or a translucent membrane should be immediately transferred to pediatric neurosurgery for evaluation and emergent closure. In a child known to have spina bifida with a cerebrospinal fluid (CSF) shunt (VP shunt): go to the emergency department if experiencing severe headache + vomiting + lethargy + bulging fontanelle + ocular deviation – these signs suggest CSF shunt malfunction requiring urgent neurosurgical management. For outpatient follow-up of children and adults with spina bifida, Clinique Omicron offers consultations at its service points in Quebec and via telemedicine. To book an appointment, visit cliniqueomicron.ca.
Consult at Clinique Omicron
Clinique Omicron's physician associates and nurse practitioners (PAs and NPs) prescribe peri-conceptual folic acid supplementation, organize follow-up for pregnancies with in-utero diagnosed spina bifida in collaboration with fetal medicine centers, manage follow-up for recurrent urinary tract infections related to neurogenic bladder, manage comorbidities in adults living with spina bifida (hypertension, kidney failure, diabetes, orthopedic complications), and promptly refer to neurosurgical emergencies in case of shunt malfunction. Consultations are available at several service points across Quebec and via telemedicine. To book an appointment, visit cliniqueomicron.ca.
The content of this page is provided for informational purposes only and is not a substitute for the advice of a doctor, pediatric neurosurgeon, or pediatrician. Spina bifida requires specialized, lifelong multidisciplinary follow-up. Latex allergy is present in 20 to 65 % of patients with spina bifida—always mention this potential allergy during any medical or surgical care.
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