Closed-feedback control of laser soldering of rat skin using diode laser

Abstract

Tissue laser soldering is a method of closure of incisions that in principle may have advantages over conventional closure methods. It is a non-contact technique, continuous and watertight and the procedure is faster and requires less skill to master. However, in practice there have been difficulties in obtaining strong and reliable welding. The quality of the weld depends on the ability to monitor and control the surface temperature of soldering zone during the procedure. Our goal was to use laser soldering to seal cuts in rat skin under temperature feed-back control and compare the results with standard sutures. Full-thickness incision created on the dorsum of rats and albumin solder with Indocyanine- Green (ICG) dye was added between the incision edges and photothermally coagulated with diode laser. We have developed an automated soldering system based on diode laser, IR detector, photodiode, digital thermocouple and camera. The true temperature of the heated tissue was determined by using and improved calibration soft ware method. Laser soldering was carried out spot by spot until it reached a preset value of 70-75°C at each point. The tensile strength of laser soldered cuts was measured after 2-10 days postoperatively and was found comparable to that of sutured cuts. Histopathological studies showed better healing and less inflammatory reactions than that caused by standard sutures after 7th day. © 2008 Springer-Verlag.