The Twister Fiber: A Comparative Study of Tissue Interaction Between This Novel Fiber and the Side-Firing Fiber Using the 980 nm Laser in Bovine Kidneys

Twister fiber has been recently introduced to convey the 980 nm laser. It is an end-firing fiber with terminal angulation. Theoretically, this fiber has many advantages over the standard side-firing fiber. Tissue characterization for such fiber has not been performed until now. It is important to carry out such a task to better understand the performance of this type of laser using this new fiber. Ablation capacity, fiber degradation, and maximum coagulation depth were tested for both the side-firing and the Twister fibers using a 980 nm diode laser system with a maximum output of 300 watts (Ceralas 300 system). The fibers have been tested on bovine kidneys. Laser powers used were 50, 100, 150, and 200 watts. The application time was 3 minutes for each experiment. Each experiment was repeated six times. Ablation rate was directly proportional to laser power reaching 2.4 +/- 0.24 g/minute for the side-firing fiber and 1.83 +/- 0.23 g/minute for the Twister fiber when the 200 watts power was reached. There was no statistical significant difference between the two fibers except at the 200 watts power. The side-firing fiber seems to resist degradation better at high power. The maximum coagulation depth was equivalent and did not significantly increase with power increase beyond the 100 watts. At 50 watts, the coagulation depth was significantly lower in the side-firing fiber. Both fibers produced significantly smaller coagulation at the 50 watts power setting compared with higher powers. In conclusion, both fibers performed well with regard to the ablation rate and produced a reasonable coagulation zone beyond the ablation area. The side-firing fiber seems to resist degradation more than the Twister fiber.