Pediatric challenge

This case presented an extraordinary challenge: a 10-month-old child with failure to thrive, excessive sleepiness, and an inability to sit—symptoms that led to imaging revealing two giant posterior circulation aneurysms: one arising from the basilar artery and the other, a partially thrombosed dissecting pseudoaneurysm from the right AICA. Both lesions were unruptured but caused obstructive hydrocephalus and significant mass effect.

The management strategy discussed during the session exemplified both sound clinical reasoning and thoughtful risk stratification. I completely agree with the decision to address the dissecting AICA aneurysm first with parent vessel occlusion. The extremely high rupture risk (approaching 99%) made this lesion the immediate threat. Proceeding with this step first, using intraoperative neuromonitoring (IONM), offered a controlled way to manage potential ischemic injury, which did manifest as a small infarct in the right cerebellar peduncle. However, the child improved without any lasting neurological deficits, underscoring the appropriateness of the approach.

A lively discussion followed regarding anticoagulation post-occlusion. While Dr. Patankar recommended anticoagulants to prevent retrograde thrombosis, I align more with Dr. Alsaadawi's cautious approach: I would avoid prophylactic antiplatelet or anticoagulation therapy, especially in the context of another unsecured giant aneurysm and a possible necessity of a CSF diversion procedure.

When it came to managing the basilar artery aneurysm, the lack of robust posterior communicating arteries initially raised concerns about parent vessel occlusion. However, the balloon occlusion test demonstrated adequate collateral flow through the PCAs, allowing for a treatment attempt. Dr. Vincent’s team chose to deploy a contour device at the aneurysm neck followed by tight coil packing. Personally, I am not fully convinced about the efficacy of contour devices in such settings. My initial plan would have favoured a direct parent vessel occlusion after confirming collateral sufficiency, followed by high-dose steroids to mitigate thrombus-induced edema. That said, watching this session helped me appreciate the rationale behind gradual aneurysm decompression with proximal vessel occlusion to reduce mass effect while avoiding abrupt thrombosis.

Post-treatment, imaging initially raised concerns when posterior communicating arteries appeared absent on angiography. However, MRI MRA clarified this was an artifact due to the dense coil mass. Clinically, the child remained stable and underwent endoscopic third ventriculostomy (ETV) as a precautionary measure against evolving hydrocephalus. Personally, I would have deferred CSF diversion until clinical signs mandated it. An EVD can always be placed emergently, and I do not favour prophylactic diversion in such scenarios.

Unfortunately, follow-up imaging showed aneurysm recanalization with device displacement, prompting re-intervention. In a silicon flow model demonstration, Dr. Adnan Siddiqui illustrated a stepwise balloon-assisted technique to occlude the proximal basilar artery while allowing gradual aneurysm decompression. His method—coiling into the parent vessel while controlling flow with a balloon—highlighted an elegant solution to a complex problem. I appreciated the logic behind not occluding both proximal and distal basilar segments simultaneously, which could have triggered catastrophic thrombosis.

Dr. Louis Delamarre appropriately cautioned about antiplatelet use in infants due to uncertain coagulation responses. The final 12-month follow-up MRI showed aneurysm regression, resolution of brainstem edema, and clinical improvement, validating the staged and conservative strategy.

In my practice, I recommend monthly clinical and 6-monthly radiological follow-up until complete aneurysm exclusion is confirmed. This case exemplifies the delicate balance required in paediatric neurointervention between decisiveness and restraint.

Top 5 Learning Points: Giant Basilar Aneurysm in an Infant

1. Staged Intervention Can Optimize Safety in Complex Paediatric Aneurysms
2. Balloon Occlusion Testing with IONM is Crucial for Safe Parent Vessel Sacrifice
3. Anticoagulation Decisions Must Balance Thrombosis and Hemorrhage Risks
4. Gradual Decompression of Giant Aneurysms May Reduce Catastrophic Thrombosis Risk
5. Close Clinical and Imaging Follow-Up is Essential for Long-Term Outcomes

References:

1. Meyers PM et al. "Paediatric Neurointerventional Procedures: Indications, Techniques, and Outcomes." AJNR Am J Neuroradiol, 2023.
2. Del Curling O Jr. et al. "Giant Intracranial Aneurysms: Natural History and Management Strategies." Neurosurgery, 2022.
3. Halbach VV et al. "Endovascular Therapy for Paediatric Intracranial Aneurysms." J Neurosurg Pediatr, 2021.