Abstract Number ‐ 105: Development of Non‐Surgical Intracranial Access to the Subdural Space for Theranostic Applications in Neurology

Introduction The objective of this study was to test the hypothesis that trans‐dural venous sinus (tDVS) puncture from within the Superior Sagittal Sinus (SSS) is feasible. Furthermore, we determine the feasibility of accessing extravascular intracranial spaces overlying the cortex using an endovascular Inside‐Out (‘I/O’) tDVS. Aims: Characterize puncture of the SSS using different size profiles and perform force measurements on benchtop and ex‐vivo models. Identify the system requirements for endoluminal opposition to mediate controlled tDVS penetration. Demonstrate a system capable of tDVS penetration and subdural‐meningeal access over the cortical convexity. Methods Silicone tube and 3D printed Superior Sagittal Sinus models were developed to assess different systems. Various re‐entry catheters (Cordis Outback, Philips Pioneer, BS Stingray LP CTO), as well as a modified construct (comprised of a 5Fr angio catheter, a BS Offroad Lancet, and a distal‐end‐cut 0.014” microguidewire), were each tested on silicone tube models. To provide endoluminal apposition for controlled tDVS penetration, various stents, stentrievers, non‐compliant balloon and compliant balloon catheters were assessed in conjunction with penetrator devices on tubular and ex‐vivo cadaveric models. To measure the force of various penetrator devices, a vector force gauge was used (3 trials by 2 independent operators). The Right Internal Jugular Vein access in a human cadaver was obtained by cut down and a purse string suture. Balloon microcatheters were advanced into the SSS under fluoroscopy. SSS catheterization with re‐entry devices required transcranial burr hole access due to inability to advance these beyond the jugular‐sigmoid junction. Results The Cordis Outback Re‐Entry device abutted endoluminally by a compliant balloon (Stryker Transform) most reliably enabled tDVS puncture on ex‐vivo specimens (Figure 1). Only the compliant balloon provided adequate endoluminal radial support for penetrator deployment on silicon tube models, as well as enabled repositioning. The modified construct was also successful in penetrating the DVS but required extensive manual manipulation for optimal positioning and apposition. The other support devices resulted either in kickback or insufficient radial support. In the cadaver, The Outback device markers were oriented to penetrate the SSS in a para‐sagittal trajectory after inflating the complaint balloon. The 22G cannula was deployed, and under fluoroscopy, an exchange‐length microguidewire was advanced through the Outback and into subdural meningeal space. The Outback was then exchanged for a 0.021” microcatheter. Once in the subdural‐meningeal space, the microguidewire was withdrawn and contrast injections were performed to assess the space catheterized, which was confirmed as subdural (Figure 2). Conclusions •Controlled tDVS penetration from an endovascular location is feasible with minimal force using a complaint endoluminal support structure. •Catheter access beneath the intracranial subdural meningeal space overlying the cortex may represent a viable route for theranostic neurologic applications. •An in‐vivo study is needed to establish the feasibility and safety of tDVS access to the cortical surface.