10.2 Congenital Neurologic Abnormalities and Surgery

10.2 Congenital Neurologic Abnormalities and Surgery

Quick Answer: For an open myelomeningocele, resuscitate first, then cover the sac with a moist sterile nonadherent dressing, keep the infant prone or side-lying, and stay latex-free. Watch head growth and lower-cranial-nerve signs because hydrocephalus and Chiari II malformation travel with the defect. Repair is usually within 24–72 hours; a ventriculoperitoneal shunt is added when ventricles enlarge or the wound leaks cerebrospinal fluid.

Scope of this section

The Neonatal CCRN Test Plan names congenital neurologic abnormalities and neurologic surgery as distinct leaves. In the NICU they are one workflow: protect exposed neural tissue, prevent infection and latex sensitization, measure the head, and get the infant to the operating room in a condition neurosurgery can use. This section does not teach germinal-matrix hemorrhage, periventricular leukomalacia, or therapeutic hypothermia. Those ischemic and hemorrhagic topics, and the pain and state work that follows them, belong in the next chapter.

OpenExamPrep is independent study material covering the patient problems listed on AACN Certification Corporation's current Neonatal CCRN Test Plan. It is not an official AACN product. Practice items for this exam remain at /practice/ccrn-neonatal.

Myelomeningocele

Myelomeningocele is an open neural-tube defect in which the spinal cord and nerves are exposed in a sac, most often in the lumbosacral region. Failure of primary neurulation leaves a neural placode that can be injured by drying, pressure, or stool. Motor and sensory loss occur at and below the lesion. Neurogenic bladder and bowel are expected, not optional extras. Club feet and hip dysplasia are common orthopedic companions. Almost all infants with myelomeningocele have a Chiari II hindbrain configuration on imaging; only a minority are symptomatic on day 1. A large majority develop hydrocephalus that will need cerebrospinal-fluid diversion.

Delivery planning, when the diagnosis is known, includes a latex-free warmer, sterile saline, a nonadherent dressing (often Telfa), gauze, and a plastic cover to hold moisture. Follow Neonatal Resuscitation Program priorities. If intubation is required, the infant may need a brief supine period with the sac centered over a foam ring or donut so the placode is not crushed. Once the airway is stable, turn prone or side-lying.

Cover the sac immediately with a sterile, saline-moist, nonadherent layer. Keep it moist; desiccation injures remaining neural tissue. A transparent drape or loose wrap holds the dressing without pressure. Place a plastic barrier so stool cannot soil the placode. Do not paint the sac with povidone-iodine or silver sulfadiazine as a default “prep.” Do not leave the lesion open to room air for photographs. Many teams start perioperative antibiotics (commonly ampicillin plus gentamicin) and continue them briefly after closure—follow the neurosurgical plan rather than inventing a week-long course.

Measure occipitofrontal circumference at birth and then at a unit-defined interval (often daily, sometimes twice weekly once stable). Palpate the fontanelle every shift. Obtain a baseline head ultrasound. Examine the lesion: level, size, intact membrane versus cerebrospinal-fluid leak. Examine the legs for spontaneous movement and the anus for tone. Urology consultation and a clean-intermittent-catheterization plan usually start before or immediately after closure because the bladder is neurogenic even when the infant is otherwise well.

Closure is typically within 24–72 hours once the infant is warm, pink, and metabolically usable. Some fetuses have intrauterine repair; those infants still need latex precautions, wound watches, and hydrocephalus surveillance. Prenatal closure changes the wound, not the need for a NICU system of care.

Encephalocele

An encephalocele is a skull defect through which meninges, and sometimes brain, herniate. Occipital lesions are more common in many Western series; anterior (sincipital) lesions are more common in some other regions. An intact sac is still fragile. An open or leaking sac is covered with the same moist sterile nonadherent technique used on the back. Position so the lesion is not dependent and not pressed against a mattress. Airway can be difficult with large occipital masses during intubation—plan two-person positioning. Associated anomalies (other neural-tube defects, hydrocephalus, facial clefts) drive imaging and genetic consultation. Postoperative nursing watches for cerebrospinal-fluid leak, wound breakdown, seizures, and rising head size.

Hydrocephalus

Hydrocephalus is excess cerebrospinal fluid under pressure, from obstruction (aqueductal stenosis, Chiari II, post-hemorrhagic—hemorrhage details in the next chapter), impaired absorption, or, rarely, overproduction. In the neonate the skull can expand. Watch for a full or bulging fontanelle, splayed sutures, occipitofrontal circumference that crosses percentiles, frontal bossing, dilated scalp veins, setting-sun (downward) gaze, irritability or lethargy, vomiting, and late apnea or bradycardia. Serial ultrasound tracks ventricular size. A lumbar puncture is not a treatment for obstructive hydrocephalus and can be dangerous when a mass lesion is suspected.

Treatment is surgical diversion once the infant is a candidate: ventriculoperitoneal (VP) shunt is the durable neonatal device; a temporizing ventricular reservoir or external ventricular drain is used when the abdomen is not ready, protein or blood is high, or infection is active. Nursing after shunt placement includes head-circumference trend, fontanelle, wound, and a look at the abdominal insertion site. Shunt malfunction is rising pressure: the infant who was comfortable becomes irritable, feeds poorly, has a fuller fontanelle, or has apnea. Shunt infection is fever, erythema along the tract, or cerebrospinal-fluid leukocytosis if a tap is performed. Overdrainage can produce a sunken fontanelle and later slit-ventricle problems. Families need a written list of return precautions before transfer out of intensive care.

Chiari II malformation

Chiari II malformation is hindbrain herniation—cerebellar vermis, brainstem, and fourth ventricle—through the foramen magnum, almost always in the company of myelomeningocele and a small posterior fossa. Symptomatic infants show lower-cranial-nerve and respiratory-control failure: biphasic stridor, weak or hoarse cry, poor swallow and aspiration, central or obstructive apnea, opisthotonus, and vasomotor instability. Mild radiographic Chiari II without these signs is watched. Progressive brainstem signs after back closure, especially with worsening hydrocephalus, need urgent neurosurgical review. Some infants require decompression in addition to a shunt. Do not attribute all stridor after myelomeningocele repair to “normal postoperative noise.”

Arteriovenous malformation and the vein of Galen

A brain arteriovenous malformation (AVM) in the neonate that matters at the warmer is most often a vein of Galen malformation: high-flow arteriovenous shunting into a dilated median prosencephalic vein. The infant presents with high-output heart failure, bounding pulses, a wide pulse pressure, pulmonary hypertension, and sometimes a cranial bruit. The “lesion” is inside the head, not on the back. Immediate care is cardiac and respiratory support, not a moist dressing. Definitive therapy is staged endovascular embolization in a center that does this work, not an emergency NICU clip. Intraventricular hemorrhage from other vascular lesions is a next-chapter topic; mention AVM here so you do not force every intracranial problem into a neural-tube pathway.

Latex caution

Infants with neural-tube defects and frequent bladder catheterization have a well-documented high rate of latex allergy. Start latex-free gloves, catheters, tape, and equipment at birth—not after the first intraoperative anaphylaxis. Label the bed. Teach every rotating learner. This is a systems habit, not a single sticker.

Preoperative and postoperative nursing

Preoperative goals: normothermia (an open sac loses heat and water), glucose and fluid stability, prone or side-lying positioning even during many feeds, a clean moist dressing, stool barrier, serial head measures, family seeing the infant’s face, and a consented plan for closure and possible later shunt. Keep the infant NPO as anesthesia directs. Avoid rectal temperatures if they threaten the dressing. Document baseline leg movement so postoperative change is not missed.

Postoperative goals after back closure: remain prone or lateral for a unit-defined period (often several days) to protect the incision; neurosurgery owns dressing changes unless they delegate; call immediately for a wet dressing, cerebrospinal-fluid leak, or wound edge separation. Continue latex precautions for life. Restart clean intermittent catheterization on the urology schedule. Watch for Chiari II signs and for hydrocephalus that declares after the sac is no longer a pressure pop-off. Pain control matters, but the detailed pain and sedation chapter is next; here, know that an under-treated infant will fight the position you need for wound healing.

Worked scenario. A 37-week infant is born with a leaking lumbosacral myelomeningocele. After positive-pressure ventilation on a foam ring, the team covers the sac with saline-moist Telfa and a plastic drape, turns the infant prone, and starts latex-free cares. Day-of-life-0 head circumference is 35 cm with a soft fontanelle. Closure occurs at 30 hours. On day 4 the fontanelle is full, circumference is 36.8 cm, and the incision is damp. This is progressive hydrocephalus with a possible leak—neurosurgery and a shunt discussion, not a “wet diaper near the back” note.

• Resuscitate first; then cover, turn, and stay latex-free.
• The sac is not a handle and not a drying rack.
• Head circumference is a vital sign in this population.
• A damp postoperative dressing is a neurosurgical page, not a routine linen change.