Introduction Flow diversion represents a paradigm shift in the treatment of certain intracranial aneurysms. Currently, the only flow diversion device available in the US is the Pipeline Embolization Device. While this has been a dramatic new tool for the treatment of intracranial aneurysms, its use has been marked by technical nuances and challenges, particularly related to the delivery system. For this reason, a new delivery system has been  introduced - the Pipeline Flex. While this system uses a braided implant identical to the original, the delivery system has been significantly modified. Here, we present the first seven cases using this new system in the US, prior to its approval by the FDA.

Methods We utilized the compassionate and/or emergency use pathway through the FDA to use the Pipeline Flex System prior to it's approval. This pathway requires the approval of the manufacturer, clinical justification, and an assessment from an uninvolved physician. Through this individual case approval process, we performed embolization using the Pipeline Flex system to treat seven aneurysms in seven different patients at seven different institutions. These cases represent all of the uses of the new Flex system in the U. S. prior to it's approval.

Results These cases demonstrated several advantages of the new Flex system. The first of which is more spatially precise delivery, as there are frequent instances in which deployment of a flow diverter is ideally within a very narrow landing zone. Additionally advantageous is the elimination of the capture coil and the need to torque the pusher wire for detachment. Finally, the ability to resheath the device also increases the users’ ability to fully open the device and appose the vessel wall.

Some technical differences were also noted with respect to the use of the new Flex device compared to the original Pipeline. Specifically, the initial deployment of the device is dependent on the proper opening of the delivery sleeves. In several of our cases, the device was initially opened in a more distal vessel in order to release the device from these sleeves, then resheathed to cause inversion of the sleeves. Upon redeployment, the device then opens immediately because the sleeves have already been flipped distally relative to the device. The new delivery system also utilizes a more robust pusher wire with a tapered proximal bumper. This allows easier movement of the delivery wire within the device after deployment, and also makes microcatheter recapture of the delivery wire much easier. Finally, we utilized 3D silicon models in two of our cases in order to rehearse the procedure before treatment. This can be a particularly useful initial step to anticipate the behavior of the device and delivery system.

Conclusion We found that the new system offers several advantages, including more precise delivery, the ability to recapture the device, and the elimination of the capture coil. And the compassionate and emergency use pathways offer the ability to utilize critical devices that are otherwise unavailable if not yet approved by the FDA.

Disclosures M. Froehler: None. K. Ebersole: None. E. Duckworth: None. A. Arthur: 2; C; Covidien. I. Ross: None. R. Hanel: 2; C; Covidien. C. Moran: 2; C; Covidien.