Temperature controlled CO2 laser welding of soft tissues: Urinary bladder welding in different animal models (rats, rabbits, and cats)

Background and Objective: Laser welding of tissues is a method of closure o f surgical incisions that, in principle, may have advantages over conventio nal closure methods. It is a noncontact technique that introduces no foreig n body, the closure is continuous and watertight, and the procedure is fast er and requires less skill to master. However, in practice, there have been difficulties in obtaining strong and reliable welding. We assumed that the quality of the weld depends on the ability to monitor and control the surf ace temperature of the welded zone during the procedure. Our objective was to develop a "smart" fiberoptic laser system for controlled temperature wel ding. Study Design/Materials and Methods: We have developed a welding system base d on a CO, laser and on infrared transmitting AgClBr fibers. This fiberopti c system plays a double role: transmitting laser power for tissue heating a nd noncontact (radiometric) temperature monitoring and control. The "true" temperature of the heated tissue was determined by using an improved calibr ation method. We carried out long-studies of CO2 laser welding of urinary b ladders in various animal models. Cystotomies were performed on the animals , and complete closure of the bladder was obtained with a surface temperatu re of 55 +/- 5 degrees C at the welding site. Results: In early experiments on 31 rats, the success rate was 73%. In late r experiments with 10 rabbits and 3 cats, there was an 80% and a 100% succe ss rate, respectively. Conclusion: The success rate in these preliminary experiments and the quali ty of the weld, as determined histologically, demonstrate that temperature controlled CO2 laser welding can produce effective welding of tissues. The fiberoptic system can be adapted for endoscopic laser welding. (C) 1999 Wil ey-Liss, Inc.