**5. Future directions**

The future of neuroendovascular surgery is bright. The technology platforms for access, delivery and treatment continue to improve at exponential rates. As it is there has been a rapid change in the number of brain aneurysm patients treated with endovascular treatment versus open surgical clipping. With this change comes a great void in experience and skill in the open surgical management of brain aneurysms. It remains to be seen whether this skill will be needed in the future [97].

#### **5.1 Flow disruptor**

Currently there is only one flow disruptor available in the US market; the WEB device. Currently, its limitations lie in the fact that it is only available in sizes to treat aneurysms 3–10 mm in size. The second limitation exists in its delivery system which, at larger sizes requires a 33-microcatheter, and at smallest sizes requires a 21-microcatheter. As newer generations come to market over the next 5 years, we expect there to be improved deliverability, different shapes available, and smaller designs for smaller ruptured aneurysms [98].

#### **5.2 Flow diverter**

Currently there are two flow diverter stents available in the US Market, the Pipeline Flex (2nd generation), and the Surpass. Currently the bulk of innovation required with this technology is in finding a coating for the stent that might mitigate the need for dual anti-platelet therapy. The second area of innovation is in the deliverability of the stents, currently needing 27-microcatheter for delivery, there is an expectation that these stents can be delivered through a 21-microcatheter in the near future, with also smaller diameter stent sizes available to treat more distal aneurysms. We fully expect the indications on which type of aneurysms can be treated in the near future.

#### **5.3 Endosaccular coiling**

Coiling has likely reached its technological pinnacle. There has been little advancement in this technology over the last 5 years. One area of interest is in endosaccular flow disruptor type coils such as the Medina system. This is not as of yet FDA approved and remains to be seen whether this is efficacious or safe. Also the adjunctive tools for coiling continue to improve such as the Atlas stent, Pulserider stent and barrel stent which all are improvements for the treatment of bifurcation aneurysms and make difficult to coil aneurysms easier. We expect further improvements in these designs, and with improvements in deliverability. In addition to stents, the balloons available for balloon assisted coiling continue to improve in shape, design and deliverability which are particularly helpful in the setting of a ruptured small or wide necked aneurysm [99].
