A novel ultrasmall composite optical fiberscope.

Background: Accurately aiming laser energy at a target from a two-dimensional endoscopic view is difficult during endoscopic laser surgery, particularly when the endoscope and the laser fiber are misaligned. We developed a composite optical fiberscope (COF) that can simultaneously visualize a target area and perform laser irradiation. The identical orientation of the endoscope and the laser fiber allows intuitive aiming at a target, even from a two-dimensional endoscopic view.

Methods: We developed an ultrasmall COF (1.1-mm diameter) with a central cauterizing laser fiber surrounded by imaging and illumination fibers as a tool for various surgical applications. Porcine mesenteric blood vessels were laser irradiated in vivo and the procedure was filmed using ultrahigh-speed (max 1,000,000 frames per second) and thermographic cameras. Blood flow and vessel diameters were measured before and after laser irradiation.

Results: The target vessels were highly visible and laser energy was delivered to the center of the view. Images from the ultrahigh-speed camera showed the blocking of the target vessel by the laser irradiation. The irradiated point initially became constricted, then discolored, and then decreased in size. Blood flow was decreased by 81.7% after laser irradiation and the diameter of the vessels at the irradiated point was approximately 46-48% smaller than that of the unirradiated vessels. Medical doctors also confirmed that the blood vessel was blocked after the experiments.

Conclusions: Our new laser surgery device may be useful for many surgical applications because it allows simultaneous diagnosis and treatment as well as intuitive aiming at a target despite its ultrasmall 1.1-mm diameter.