Treatment of Hydrocephalus with Ventriculomegaly Using Ventricular Shunts
For hydrocephalus with ventriculomegaly, both ventriculoperitoneal (VP) shunts and endoscopic third ventriculostomy (ETV) are equivalent treatment options with moderate clinical certainty, though VP shunts remain the most common surgical approach when ETV is not anatomically feasible or has failed. 1
Primary Treatment Decision Algorithm
First-Line Considerations
Assess anatomical suitability for ETV versus VP shunt placement:
For obstructive hydrocephalus with aqueductal stenosis and suitable anatomy: Consider ETV first, as it demonstrates lower failure rates after the initial 3-month period compared to shunts, despite higher early failure rates. 2, 3
For communicating hydrocephalus or unsuitable ETV anatomy: VP shunt is the recommended treatment. 2, 3
For patients with complex ventricular anatomy or failed ETV: VP shunt placement is indicated. 3
VP Shunt Indications
Proceed with VP shunt when patients demonstrate:
- Progressive ventriculomegaly with symptomatic increased intracranial pressure (headache, altered mental status, gait abnormalities, urinary incontinence) 2, 3
- Rapidly enlarging head circumference (>2 cm in <7 days in neonates) 1
- Increased splaying of cranial sutures with full, tense fontanel 1
- Worsening apnea, bradycardia episodes, lethargy, or feeding intolerance in infants 1
Special Population Considerations
Premature Infants with Posthemorrhagic Hydrocephalus
Use temporary CSF diversion initially:
Ventricular reservoir or ventriculosubgaleal (VSG) shunt should be placed when clinical symptoms develop, after failure of serial lumbar punctures, and ideally after active systemic infections are treated. 1
The goal is delaying permanent shunt insertion until the infant reaches approximately 2.5 kg to decrease infection risk. 2, 3
Ventricular reservoirs require tapping frequency from twice daily to twice weekly, tailored to minimize clinical signs of elevated intracranial pressure. 1
VSG shunts direct CSF to a contralateral subgaleal pocket where it collects and is slowly reabsorbed. 1
Do not routinely remove temporary shunts that appear no longer needed. 1
Pediatric Patients
For shunt insertion before 1 year of age, approximately 45% require revision within 9 months, necessitating close follow-up. 2, 3
Use antibiotic-impregnated shunt tubing or strict infection reduction protocols in high-risk populations. 2, 3
Myelomeningocele Patients
Conservative management is acceptable for asymptomatic ventriculomegaly:
Monitor for progressive macrocephaly, signs of neurological dysfunction, and progressive ventricular enlargement. 1
Current evidence is insufficient to conclude that persistent ventricular size adversely impacts neurocognitive development. 1
Both ETV with choroid plexus coagulation (CPC) and VP shunts show similar neurocognitive outcomes, though ventricles often remain enlarged with ETV/CPC. 1
Achondroplasia Patients
ETV is preferred over VP shunts when feasible:
ETV achieves complete symptom resolution in 75% of cases with lower complication rates than VP shunts. 1
All revision procedures, complications, and deaths in this population were associated with VP shunts rather than ETV. 1
Caution: Skull base and third ventricle anatomy in achondroplasia can present technical challenges including narrow prepontine space, absent interpeduncular cisterns, and risk of basilar artery injury. 1
Contraindications to VP Shunt Placement
Absolute Contraindications
Relative Contraindications
- Active systemic infection without CNS involvement (delay until controlled, as shunt infection occurs in approximately 11% of initial placements within 24 months) 3
- Recent abdominal surgery with peritoneal inflammation (consider alternative distal sites or delay) 3
Complication Prevention and Management
Infection Prevention
Implement strict protocols:
Administer gram-positive antibiotic coverage before skin incision, reducing infection risk from 10.7% to 5.9%. 3
Use antibiotic-impregnated catheters in high-risk patients (previous shunt infection, recent revision, premature infants), with odds ratio for infection reduction of 0.21 (95% CI 0.08-0.55) in pediatric patients. 3
Shunt infection occurs in approximately 11% of initial CSF shunt placements within 24 months. 2
Shunt Failure Monitoring
Primary shunt failure occurs within 3 months in 12.6% of cases in preterm infants with posthemorrhagic hydrocephalus. 2
Regular monitoring of shunt function and neurological status is essential for early detection of complications. 2
Management of Shunt Infection
- Complete removal of infected shunt along with systemic antibiotics is required. 2
Expected Outcomes
Ventricular Size Response
Persistent ventriculomegaly does not necessarily indicate treatment failure:
With VP shunts, ventricular size typically shows gradual reduction over approximately 1 month postoperatively. 4
With ETV, ventricles often remain enlarged even when clinically effective at reducing intracranial pressure. 1
There is no correlation between reduction in ventricular size and clinical improvement in many cases. 5
Clinical Improvement
Fast clinical improvement typically occurs within the first 2 days after VP shunt surgery with remission of intracranial hypertension symptoms. 4
For normal pressure hydrocephalus, 91.2% show overall improvement at 12 months. 3
Common Pitfalls to Avoid
Do not place VP shunt during active untreated infection without establishing appropriate antimicrobial therapy first. 3
Do not automatically assume ETV is contraindicated in appropriate candidates, as it has lower failure rates after 3 months compared to shunts. 3
Do not rely solely on ventricular size reduction as a measure of treatment success, as clinical improvement may occur without significant size reduction. 5
Do not use routine serial lumbar punctures as definitive treatment (Level I evidence against this approach). 6