title: Experimental endoscopic endovascular cannulation: a novel approach to thrombolysis in retinal vessel occlusion.
abstract: OBJECTIVE
  Recent studies suggest that the cannulation of retinal vessels may provide a potential access route for the administration of thrombolytic agents in retinal vessel occlusion. However, the major problem with available techniques is the limited visualization of retinal vessels with conventional surgical microscopes, making it difficult to effectively control the targeted injection of drugs.
  
  
  METHODS
  The authors developed a novel single-piece catheter system for the endoscopically guided puncture of microvessels. Experimental punctures of retinal vessels with injection of fluid were performed in porcine cadaver eyes using a standard high-resolution gradient index microendoscope introduced through the pars plana.
  
  
  RESULTS
  Endoscopically guided punctures were successfully performed in porcine branch retinal veins at various distances from the optic disc. Injection of recombinant tissue plasminogen activator (rt-PA), hypertonic solution (hyper HES), or normal saline solution into the vessel lumen was accomplished under direct endoscopic view in a safe and reliable manner.
  
  
  CONCLUSIONS
  Endoscopically guided puncture of retinal microvessels is feasible and can be performed through a pars plana entry without additional micromanipulation devices. This novel technique may be a safe and effective approach to catheter-directed endovascular thrombolysis in retinal vascular occlusive diseases.
authors: Department of Ophthalmology, Klinikum Ludwigshafen, Ludwigshafen, Germany. hattenbach.lo@klilu.de
authors: Lars-Olof
authors: LO
authors: Hattenbach
authors: Joachim
authors: J
authors: Puchta
authors: Ingo
authors: I
authors: Hilgenberg
mesh_terms: D000818:Animals; D002404:Catheterization / Q000295:instrumentation; D002406:Catheterization, Peripheral / Q000379:methods; D004195:Disease Models, Animal; D004724:Endoscopy / Q000295:instrumentation; D005343:Fibrinolytic Agents / Q000008:administration & dosage*; D007262:Infusions, Intravenous; D011994:Recombinant Proteins / Q000008:administration & dosage; D012169:Retinal Vein / Q000187:drug effects*; D012170:Retinal Vein Occlusion / Q000188:drug therapy*; D013552:Swine; D015912:Thrombolytic Therapy / Q000379:methods*; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage*
chemical_list: D005343:Fibrinolytic Agents; D011994:Recombinant Proteins; D010959:Tissue Plasminogen Activator