Intraluminal albumin stent assisted laser welding for ureteral anastomosis

Background and Objectives: The success of laser tissue welding or soldering depends on optimal laser settings, solder material, and tissue type and geometry. To develop a practical laser welding technique for ureteral repair, an intraluminal albumin stent was designed to enhance the welding effects on ureteral end to end anastomosis. Study Design/Materials and Methods: In vitro porcine ureters were anastomosed using an albumin stent alone, the albumin stent plus a solder, and the solder alone. All welding was performed with an 810-nm diode laser with either a continuous wave (1 W, CW) or two pulse modes (2 W, 3.3 Hz; 1 W, 5 Hz). Laser parameters, tensile strength (TS) and burst pressure (BP) of the ureteral anastomosis, and tissue thermal injury were measured. Results: In the 2-W pulse mode, BP in the albumin stent plus solder group (mean 185 mmHg) and the stent only group (mean 133 mmHg) were significantly higher than the solder only group (mean 77 mmHg, P < 0.05). Laser ureteral anastomosis with the stent plus solder group at 1-W CW and 2-W pulse laser modes yielded the highest TS (mean 97, 82 g) and BP (mean 183, 185 mmHg). Among the three modes, the 1 W pulse delivered the lowest energy and yielded the lowest TS and BP in ureteral anastomosis. There was no significant difference in the thermal damage to the tissue among the modes and groups. Conclusions: Using the albumin stent increased the reliability of ureter end-to-end laser anastomosis. Further studies will be warranted in vivo and other tubular organs as well.