Laser-assisted vessel welding: state of the art and future outlook

Laser-assisted vascular welding (LAVW) is an experimental technique being developed as an alternative to suture anastomosis. In comparison to mechanical anastomosis, LAVW is less traumatic, non-immunogenic, provides immediate water tight sealant, and possibly a faster and easier procedure for minimally invasive surgery. This review focuses on technical advances to improve welding strength and to reduce thermal damage in LAVW. In terms of welding strength, LAVW has evolved from the photothermally-induced microvascular anastomosis, requiring stay sutures to support welding strength, to sutureless anastomoses of medium-sized vessels, withstanding physiological and supraphysiological pressure. Further improvements in anastomotic strength could be achieved by the use of chromophore-containing albumin solder and the employment of (biocompatible) polymeric scaffolds. The anastomotic strength and the stability of welds achieved with such a modality, referred to as scaffold- and solder-enhanced LAVW (ssLAVW), are dependent on the intermolecular bonding of solder molecules (cohesive bonding) and the bonding between solder and tissue collagen (adhesive bonding). Presently, the challenges of ssLAVW include (1) obtaining an optimal balance between cohesive and adhesive bonding and (2) minimizing thermal damage. The modulation of thermodynamics during welding, the application of semi-solid solder, and the use of a scaffold that supports both cohesive and adhesive strength are essential to improve welding strength and to limit thermal damage.