[Morphological findings of the mucosa after irradiation with an argon-laser an animal experiment (author's transl)]

The macroscopical and lightmicroscopical findings at the mucosa of the hamster cheek pouch after irradiation with an Argon-Ionlaser (wave-length 0.488 mum, power 200 mW, beam diameter 0.5 mm, power density 100 W/cm2) are described immediately, 1; 2,5; 5 and 10 days after irradiation. The mucosa was exposed 10 sec, 30 sec, 1, 2, 5 and 10 min to the radiation. With growing laser dosis the lesions of the mucosa and the postoperative healing time increases.A clinically useful optimal mucosa lesion with a short healing duration (within 5-10 days) is obtained only by application of a low and a middle laser dosis. There are two kinds of mucosa destruction by laser: 1. The destruction can be producing a coagulation necrosis with subsequent unbloody sloughing, resulting in an ulcus with rapid healing by complete reepithelisation and a small amount of connective tissue. 2. An immediate destruction is obtained by carbonisation of tissue after application of a middle to high laser dosis resulting in an ulcus with slow healing and also complete reepithelisation and small connective tissue. The typical laser lesion consists of 3 zones: The carbonisation zone is surrounded by a small coagulation zone followed by a zone of granulation tissue including thrombs and necrosis of the vessel walls. The unbloody procedure is based on an occlusion of the vessels immediately during laser radiation and later on by thrombosis in the periphery of the lesions. The possible clinical applications are discussed.

[Biophysical considerations of laser surgery and the application in otolaryngology (author's transl)]

In the paper biological mechanisms of laser radiation on tissue are summerized. The specific features of different types of lasers are considered, e.g. wavelength. Focussing problems to rise the power density are described. The advantages and disadvantages of laser surgery are discussed. It is shown that the laser is well suited for an otolaryngological microsurgery. The present applications in otolgaryngology consist of about 25 papers which are evaluated and concentrated. Later surgery of the larynx is of special interest. Many clinical applications have been performed. Further experimental work exists in the region of the oral and nasal cavities, of the face and the neck. Some basic research without clinical application has been performed on the cochlea and the semicircular canals. The advantages of laser surgery are e.g. lack of blood, high precision, good healing of the wound.

[The effect of the argon laser on the vessels, the macro- and microcirculation of the mucosa of the hamster cheek-pouch. An intravitalmicroscopic study (author's transl)]

The mucosa of the cheek-pouch of five golden Syrian Hamsters was irradiated with the beam of an argonionlaser (diameter 0.5 mm and 200 mW). The effect on the micro- and macro-vessels and the bloodstream, especially of the microcirculation, is studied intravitalmicroscopically. In the microcirculation and also in the small and large venous and arterial vessels a restriction of bloodstream, praestasis, pendulumstream, stream reversal and some white microthrombi, -- emboli and agglutination of erythrocytes are visible. The bloodless welding of the vessels takes place even before the evaporation and coagulation necrosis of the surrounding epithelium of the mucosa as a result of the relatively selective effect of the Argon Laser on the reddish vessel-system by a continuous narrowing of the vessels-walls to the complete loss of their lumen rather than by a thrombosis. Firstly the capillaries, the venoles and the arterioles are obliterated, then those of middle size and at last the large venae and arteries in which case large vessels function for a moment as smaller ones. A continuously growing imbibition with increasing duration of the laser irradiation can be observed. Three clinically important phenomenon, depending on the laserdose can be observed: 1. a partial, 2. a subtotal and total obliteration of the network of the vessels, and 3. a total destruction of the blood-vessels and also of the tissue. Therefore clinically a subtotal or total network obliteration of the blood-vessels of strongly vascularised tissues, haemangiomas, teleangiectasias in case of morbus Rendu-Weber-Osler and livid enlarged nasal conchae might be obtained. Further a total tissue-destruction with a break in the continuity of the tissue for example with strongly vascularised carcinoma or its metastases might be effected.