Use of CO₂ laser and AgClBr infrared transmitting fibers for tympanoplasty: Experiments on animal models

One of the most common ear diseases is Chronic Otitis Media that leads to a tympanic membrane perforation. The treatment of this condition is by a surgical procedure, tympanoplasty that is often done under local or general anesthesia. During this procedure an autologous fascia (e.g. temporal fascia) is applied to close the perforation. Commonly, fixation of the fascia is achieved mostly by Gel-Form. During the last several years various fascia fixation techniques were suggested. These included a welding procedure based on using an Argon laser. The disadvantage of the latter is that the visible Argon laser is not absorbed well by the relatively thin tympanic membrane and the fascia. It does not lead to strong weld and it may heat of the middle ear, causing neural hearing loss. The CO₂ laser infrared (IR) radiation is much more suitable for welding of these thin tissues, because of its very high absorption in tissues. There is still a need to deliver this radiation to the weld site using a thin and flexible optical fiber. In this work we have welded fascia on the tympanic membranes of guinea pigs using a CO₂ laser. Holes of diameter 2-3 mm were punctured in the membranes and a piece of fascia was placed on the holes. Laser power of the order of 0.5 W was delivered to the fascia using an IR transmitting AgClBr fiber. In experiments done on 11 animals and CO₂ laser welding was successfully done on in 15 ears. The success of these preliminary studies in the animal models shows that CO₂ laser tympanoplasty could be a very valuable surgical technique.