title: Vessel wall perforation mechanism of the excimer laser-assisted non-occlusive anastomosis technique.
abstract: The excimer laser assisted non-occlusive anastomosis (ELANA) technique is used to make anastomoses on intracerebral arteries. This end-to-side anastomosis is created without temporary occlusion of the recipient artery using a 308-nm excimer laser with a ring-shaped multi-fiber catheter to punch an opening in the arterial wall. Over 500 patients have received an ELANA bypass. However, the vessel wall perforation mechanism of the laser catheter is not known exactly and not 100 % successful. In this study, we aimed to understand the mechanism of ELANA vessel perforation using specialized imaging techniques to ultimately improve its effectiveness. High-speed imaging, high-contrast imaging, and high-sensitivity thermal imaging were used to study the laser wall perforation mechanism and reveal the mechanical and thermal effects involved. In vitro, rabbit arteries were exposed with the special designed laser catheter in a setup representative for the clinical setting, in which blood was replaced with a transparent UV absorbing liquid for visualization. We observed that laser vessel wall perforation was caused by explosive vapor bubbles tearing through the vessel wall, mostly within the first 20 of the total 200 pulses. Thermal effects were minimal. Unsymmetrical tension in the vessel wall inducing migration of the flap during laser exposure was observed in case of unsuccessful wall perforations. The laser wall perforation mechanism in the ELANA technique is primarily mechanical. Symmetric tension in the recipient vessel wall is essential and should be trained by neurosurgeons.
authors.affiliation: Brain Center Rudolph Magnus, Department of Neurosurgery, University Medical Center Utrecht, G.03.124, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.|Brain Technology Institute, Utrecht, The Netherlands.
authors.forename: Jochem
authors.initials: J
authors.lastname: Bremmer
authors.affiliation: Brain Center Rudolph Magnus, Department of Neurosurgery, University Medical Center Utrecht, G.03.124, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. T.P.C.vandoormaal@umcutrecht.nl.|Brain Technology Institute, Utrecht, The Netherlands. T.P.C.vandoormaal@umcutrecht.nl.
authors.forename: Tristan P C
authors.initials: TP
authors.lastname: van Doormaal
authors.affiliation: Brain Center Rudolph Magnus, Department of Neurosurgery, University Medical Center Utrecht, G.03.124, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.
authors.forename: Bon H
authors.initials: BH
authors.lastname: Verweij
authors.affiliation: Brain Center Rudolph Magnus, Department of Neurosurgery, University Medical Center Utrecht, G.03.124, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.|Brain Technology Institute, Utrecht, The Netherlands.
authors.forename: Albert
authors.initials: A
authors.lastname: van der Zwan
authors.affiliation: Brain Technology Institute, Utrecht, The Netherlands.
authors.forename: Cornelius A F
authors.initials: CA
authors.lastname: Tulleken
authors.affiliation: Department of Physics & Medical Technology, Free University Medical Center Amsterdam, Amsterdam, The Netherlands.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Verdaasdonk
mesh_terms: D000714:Anastomosis, Surgical; D000818:Animals; D001011:Aorta / Q000601:surgery*; D002548:Cerebral Revascularization / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D011817:Rabbits; D013524:Surgical Flaps
keywords: ELANA; Excimer laser; Surgical anastomosis