Treatment strategy for recanalization of top-of-the basilar aneurysms after simple coiling:

Tips & tricks for choosing your strategy:

• How to treat it?
• Which may be the most efficacious treatment?
• Which strategy does not impede you from doing something else if it does not work?
• How many vertebral arteries do you have? Think about the number of microcatheters you may place
• The larger the aneurysm is, the more sense it makes to take the additional risk associated with – flow diversion:
  1. Consider if you have posterior communicating arteries (do carotid occlusion tests);
  2. PcomA may offer protection and may permit you to put a flow-diverter on the other side;
  3. If the aneurysm continues to grow after a flow-diverter treatment, occluding through the PcomA with coils, the contralateral P1 segment may be an option;
  4. Use flow-diverter with coils.
  5. Aim for dense packing;

• In giant aneurysms, who already recanalized, Y-stenting and coiling is an option:
  1. Using open-cell laser-cut stents (ex Neuroform Atlast) is probably associated with lower morbidity and mortality but with a higher chance of recanalization, and it prohibits further treatment with flow diverters;
  2. Y-stenting with braided stents may be more indicated in the top of the dysplastic basilar aneurysms who already recanalized (put a dual lumen balloon through the cells of the first braided stent to dilate the cells and make room for a second stent);
  3. Y-stenting can be done with one braided and one open-cell stent.
  4. Y-stenting even if it is associated with recanalization in this situation – you may always think about coming back several times, once every two-three years, to put some coils in, with low procedural risk but without solving the problem of mass-effect if present.

• If you do Y-stenting with braided stents, expect re-catheterization of the sac to be very difficult (with LVIS EVO, this may not be even possible); Consider jailing another microcatheter inside the sac;
• Deploy braided stents in these situations without shouldering the stents at the level of the neck, even pulling a little bit on the stents (this might keep the cells open); Try to push the second stent at the level of the crossing to ensure proper opening; Re-cross the second stent with the microcatheter to ensure optimal opening of the stent;
• In Y-stenting of the top-of-the basilar, consider taking long-stents to have good distal anchoring;
• Before stenting, try to catheterize the two branches and choose to deploy your stent in the most challenging branch to catheterize;
• Aim for very dense coiling and take care not to be kicked out of the sac with your microcatheter;
• Think about using hydro-coils in aneurysms with high recanalization rates;