Spina Bifida / Myelomeningocele — Focused Clinical Examination

1. Patient / Clinical Setting

A 2-day-old newborn boy is referred to the pediatric surgery unit following the identification of a swelling over the lower back immediately after birth. His mother reports that he moves both legs, but the movements appear reduced compared with his upper limbs.

Clinical setting: The baby is clinically stable and resting in a protected prone position. A rounded midline lumbosacral swelling is visible beneath a sterile non-adherent covering. The examiner requests a focused assessment of the spinal abnormality and associated neurological findings.

2. Student Task

Examine this newborn for evidence of a congenital spinal malformation. Identify the important characteristics of the spinal swelling, assess lower limb neurological function, recognize associated abnormalities and present your most likely clinical diagnosis.

3. Focused Examination Approach

Introduce yourself to the parent or guardian, explain the examination and obtain consent. Ensure a warm environment, adequate lighting and gentle handling. The infant should remain appropriately supported in a prone or side-lying position to avoid pressure on the spinal swelling.

A. Initial Observation

• General condition: Observe activity, spontaneous movements, cry, respiratory effort and responsiveness.
• Position: Confirm that the infant is positioned without direct pressure on the spinal lesion.
• Spontaneous lower limb movement: Compare movement of both legs with the upper limbs.
• Visible abnormalities: Look for deformities of the feet, ankles or lower limbs.
• Head size: Observe for an unusually large head suggesting associated hydrocephalus.

Clinical importance: Reduced lower limb movements or congenital foot deformities may indicate neurological involvement associated with an open spinal dysraphism.

B. Inspection of the Spinal Swelling

Inspect the lesion carefully without disturbing any protective dressing unnecessarily.

• Site: Determine whether the swelling is located in the cervical, thoracic, lumbar or lumbosacral region.
• Position: Observe whether it lies in the midline over the vertebral column.
• Size and shape: Estimate the visible dimensions and describe whether the lesion is rounded or irregular.
• Surface covering: Look for intact skin, a thin translucent membrane or exposed neural tissue.
• Contents: Note any visible neural placode or tissue within the lesion without touching it.
• Integrity: Look for leakage of clear fluid, membrane disruption or surrounding inflammation.

Interpretation: A midline lumbosacral sac with exposed or visible neural tissue strongly suggests myelomeningocele. A completely skin-covered lesion without visible neural tissue may represent another form of spinal dysraphism and requires further assessment.

C. Recognition of Important Spinal Malformations

Clinical importance: Visible anatomy may suggest the type of defect, but clinical examination alone cannot always distinguish all spinal dysraphism variants. Imaging and surgical evaluation are important.

D. Lower Limb Motor Examination

Examine both lower limbs gently, assessing spontaneous and stimulus-evoked movement without causing distress.

• Muscle bulk: Look for reduced muscle mass or asymmetry.
• Hip movements: Observe spontaneous hip flexion and extension.
• Knee movements: Assess spontaneous knee flexion and extension.
• Ankle and foot movements: Observe dorsiflexion, plantarflexion and toe movement.
• Muscle tone: Assess passive resistance gently where appropriate.
• Symmetry: Compare right and left lower limb activity.

Interpretation: Reduced or absent movement in muscle groups supplied by spinal segments below the lesion suggests associated motor pathway or nerve root dysfunction. The neurological level may differ from the external vertebral level.

E. Lower Limb Reflexes and Sensory Function

• Observe appropriate withdrawal movements in response to gentle clinical stimulation.
• Compare sensory responsiveness across the lower limbs using age-appropriate methods.
• Assess knee and ankle reflexes where feasible and interpret them in the context of neonatal neurological maturity.
• Look for marked asymmetry or absent responses in the lower limbs.

Interpretation: Impaired motor and sensory responses may indicate neurological dysfunction below the spinal lesion. A newborn cannot reliably undergo the same formal sensory or power examination as an older child.

F. Examination for Associated Orthopedic Deformities

• Feet: Inspect for clubfoot or other abnormal foot positions.
• Hips: Observe abnormal limb positioning and restricted movement.
• Knees: Look for fixed flexion or extension deformities.
• Spine: Note any associated deformity without placing pressure on the sac.

Clinical importance: Congenital orthopedic deformities may arise from abnormal muscle innervation and altered fetal movement.

G. Examination for Hydrocephalus

• Head circumference: Measure the occipitofrontal circumference and compare it with gestational-age-appropriate reference values.
• Fontanelle: Assess the anterior fontanelle for fullness or bulging while the baby is calm and appropriately positioned.
• Cranial sutures: Look for abnormal separation.
• Eye position: Observe for persistent downward deviation of the eyes.
• Clinical behavior: Note poor feeding, abnormal cry, vomiting or reduced responsiveness.

Interpretation: Myelomeningocele is frequently associated with Chiari II malformation and hydrocephalus. An abnormal head examination warrants appropriate neuroimaging.

H. Brief Assessment of Bladder and Bowel Function

• Ask whether the infant has passed urine since birth.
• Assess for abnormal bladder distension.
• Ask about passage of meconium.
• Look for obvious abnormalities of the perineal region.

Clinical importance: Spinal neural involvement may cause neurogenic bladder or bowel dysfunction. Early normal voiding does not exclude later neurogenic bladder problems.

4. Important Clinical Findings

Positive Findings

Important Relevant Negative Findings

• No visible CSF leakage: No obvious fluid escape at the time of examination, although the covering remains fragile.
• No surrounding erythema or purulent discharge: No visible local evidence of infection.
• Normal upper limb spontaneous movements: No obvious upper limb motor impairment.
• Anterior fontanelle not tense or bulging: No obvious clinical evidence of raised intracranial pressure at present.
• Infant is alert and feeding adequately: No immediate clinical deterioration observed.

Absence of head enlargement or a bulging fontanelle does not exclude hydrocephalus. Similarly, absence of leakage does not remove the risk of sac rupture or infection.

5. Presentation of Findings

6. Most Likely Diagnosis

Lumbosacral Myelomeningocele with Associated Lower Limb Neurological Deficit

The characteristic external spinal defect containing neural tissue, together with reduced distal lower limb movement and hypotonia, supports the diagnosis of myelomeningocele, a form of open spinal dysraphism. Associated hydrocephalus, Chiari II malformation, orthopedic deformities and neurogenic bladder must be assessed. Clinical examination alone does not establish the full extent of neural involvement.

7. Differential Diagnosis

8. Relevant Investigations

Investigations should define the spinal abnormality, identify associated hydrocephalus and evaluate neurological or urinary complications.

• MRI spine: Defines spinal dysraphism, neural tissue involvement and associated spinal cord abnormalities when requested for surgical planning.
• Cranial ultrasonography: Assesses ventricular enlargement and possible hydrocephalus through the open fontanelle.
• Renal and bladder ultrasonography: Screens for urinary tract dilatation, bladder abnormalities and potential consequences of neurogenic dysfunction.
• Focused urinary function assessment: Monitor urine output and assess bladder emptying, with additional testing guided by the pediatric urology team.

Clinical interpretation: Imaging complements the physical examination but should not delay necessary protection of an open lesion or urgent pediatric surgical evaluation.

9. Management Discussion

• Protect the spinal lesion with an appropriate sterile, non-adherent moist dressing and maintain prone or side-lying positioning.
• Arrange prompt neonatal and pediatric neurosurgical assessment for closure of the defect.
• Monitor for CSF leakage, infection and neurological deterioration.
• Assess for associated hydrocephalus, lower limb deformities and neurogenic bladder.
• Arrange coordinated long-term rehabilitation, orthopedic and urological care after initial stabilization.

10. Red Flags / Serious Complications

• Rupture of the spinal sac or visible CSF leakage.
• Fever, lethargy or inflammation suggesting possible infection or meningitis.
• Bulging fontanelle, increasing head circumference or reduced responsiveness suggesting hydrocephalus.
• Progressive lower limb weakness or new neurological deterioration.
• Urinary retention or evidence of significant bladder dysfunction.

Sac rupture, suspected CNS infection, acute neurological deterioration or symptomatic hydrocephalus requires immediate neonatal and neurosurgical escalation.

11. Examiner Viva Preparation

Q1. What is spina bifida?

Answer: Spina bifida is a congenital spinal malformation resulting from abnormal development and closure of posterior vertebral structures, with the severity depending on associated neural tube and spinal cord involvement.

Q2. How does myelomeningocele differ from meningocele?

Answer: Myelomeningocele contains neural tissue and meninges within an external spinal defect, while a meningocele contains meninges and CSF without neural tissue within the sac.

Q3. Which examination findings suggest neurological involvement in myelomeningocele?

Answer: Reduced lower limb movement, hypotonia, impaired sensory responses, abnormal reflexes and associated foot or lower limb deformities.

Q4. Why should the head be examined in an infant with myelomeningocele?

Answer: Myelomeningocele is commonly associated with Chiari II malformation and hydrocephalus. Head circumference, fontanelle findings and neurological status may indicate ventricular enlargement or raised intracranial pressure.

Q5. Why is bladder assessment important?

Answer: Neural injury can cause neurogenic bladder, potentially leading to incomplete emptying, urinary tract infections and upper urinary tract damage.

Q6. What precautions are important when examining an open myelomeningocele?

Answer: Avoid pressure, puncture and manipulation of the sac. Maintain a protective sterile moist dressing, avoid contamination and position the infant prone or side-lying.

Q7. What is the basic management principle for a newborn with myelomeningocele?

Answer: Protect the exposed neural tissue, stabilize the newborn and arrange prompt pediatric neurosurgical assessment for defect closure, while evaluating associated hydrocephalus, neurological deficits and urinary dysfunction.

12. AIM Short Case High-Yield Review

1. Core inspection: Identify the site, size, covering and visible contents of the spinal defect.
2. Most important clue: Midline lumbosacral sac with exposed neural tissue suggests myelomeningocele.
3. Motor examination: Compare spontaneous hip, knee, ankle and foot movements.
4. Neurological involvement: Reduced lower limb movement, hypotonia and abnormal sensory responses may be present.
5. Important distinction: Meningocele contains meninges and CSF; myelomeningocele also involves neural tissue.
6. Associated abnormalities: Hydrocephalus, Chiari II malformation, foot deformities and neurogenic bladder.
7. Important investigation: Spinal MRI for anatomical assessment and cranial ultrasound for hydrocephalus.
8. Management priority: Protect the lesion and arrange prompt pediatric neurosurgical evaluation.
9. Red flags: CSF leakage, infection, progressive neurological deficit or symptomatic hydrocephalus.
10. Common examination mistake: Pressing the spinal sac or focusing only on the swelling without assessing lower limb neurological function and associated complications.