An Endovascular Cannulation Needle with an Internal Wire for the Fragmentation of Thrombi in Retinal Vein Occlusion

PURPOSE We report a newly developed device to fragment thrombi in retinal vein occlusion. METHODS The new instrument consists of a 23-gauge (G) pipe and a 37-G needle with an internal wire. A total of 40 porcine eyes were used; 20 eyes for experiments in the branch retinal vein (BRV group) and 20 eyes for experiments in the central retinal vein (CRV group). We placed 25-G 3-port trocars, and core vitrectomy was performed. Another 23-G scleral incision was performed for insertion of the needle. The needle pierced the retinal vein at a distance of three- to four- or one-disc diameters from the optic disc (BRV or CRV group, respectively), and the internal wire was advanced toward the disc. The success rates of needle piercing and cannulation of the internal wire were recorded in each group. In the CRV group, the cannulation was deemed successful when the tip reached inside the optic disc. Real-time optical coherence tomography imaging also was performed using the Zeiss Rescan 700 device in porcine eyes. Histologic examination of the retinal vessel inserted with the internal wire was performed. RESULTS The success rates of needle piercing into the BRV and CRV were 85% and 95%, respectively. The success rates of cannulation of the internal wire into the BRV and CRV were 85% and 0%, respectively. The process of cannulation was recorded successfully with the Rescan 700. Histologic examination showed no damages to the endothelial cell layer. CONCLUSIONS The needle and internal wire intended to be used for recanalization of BRV occlusion were successfully pierced and cannulated into the BRV. TRANSLATIONAL RELEVANCE This newly developed device could become a treatment modality for retinal vein occlusion to fragment thrombi that present treatment methods cannot reach and remove directly.