[The study of opportunity of aqueous humor filtration increase after nondestructive laser exposure of sclera in the site of pars plana projection (experimental study)].

Increase of scleral water permeability due to formation of porous structure after exposure of pulsed periodic radiation of erbium-glass optical fiber laser with wave length 1,56 pm was demonstrated in experimental study of cadaver human eyes in vitro and eyes of experimental animals (rabbits) in vivo. Simultaneous complex laser exposure of pars plana and ciliary processes results in summation of morphological changes that provide decrease of aqueous humor secretion, uveal drainage and extension of suprachoroid space. A base for new noninvasive technology of nondestructive laser exposure in glaucoma treatment is established.

[Holmium laser in chondrology: potentials and prospects]. / Vozmozhnosti i perspektivy primeneniia gol'mievogo lazera v khondrologii.

To study the mechanism of simulation of a cartilage, to define the optimum parameters and laser radiation regimens, the authors made a complex of in vitro experiments on the cartilages of the nasal septum in man and domestic animals and in vivo experiments on those of the concha in rabbits and pigs. Holmium laser radiation is shown to be the most suitable tool for formation of a cartilage. Evidence is provided for the possibility of irreversibly altering the shape of a cartilage during laser radiation. A procedure has been developed for non-invasive correction of the septum of the nose for its curvature. Restored or improved nasal respiration was observed in more than two thirds of the patients. Laser surgery is not of age-limited application, it is noninvasive, can be performed in the outpatient settings and requires no drug treatment in the postoperative treatment.

[Reestablishing of nasal respiration with Holmium laser in distortion of nasal septum in cartilaginous part]. / Vosstanovlenie nosovogo dykhaniia s pomoshch'iu izlucheniia gol'mievogo lazera pri iskrevlenii peregorodki nosa v khriashchevom otdele.

To study mechanisms of cartilage modelling, estimation of optimal parameters and regimens of laser radiation, the authors made in vitro and human experiments on nasal septum cartilages and in vivo experiments on cartilages of the floor of the auricle in rabbits and pig. Ho-laser radiation is thought the most appropriate tool for cartilage shaping. A method of non-invasive correction of the nasal septum cartilage in its distortion has been designed. 2/3 of the patients recovered or improved nasal respiration. Laser operation has no age restrictions, is non-invasive, can be made outpatiently, is not followed by pharmacological treatment.

Thermal and diffusion processes in laser-induced stress relaxation and reshaping of cartilage.

The thermodynamic characteristics of the 'bound-to-free' phase transformation of water are studied by means of differential microcalorimetry and FTIR spectroscopy. This phase transition controls the stress relaxation and reshaping of cartilage which we have observed previously under moderate laser heating. It is shown that the FTIR spectrum of bound water in cartilage differs from that of free water in cartilage, and that both show differences to the FTIR spectrum of pure water. The proportion of bound water in cartilage is found to be of the order 4%. We have examined water liberation and absorption kinetics and found them to be controlled by diffusion through the tissue and also by the bound-to-free water transformation. The theoretical modelling and experimental data allowed calculation of diffusion coefficients and the activation energy for water transfer. The latter was found to be close to the heat of phase transformation of water. We have established that the drying and wetting processes in cartilage are reversible (fully or in a part, depending on the temperature of preliminary drying) and can be described by identical solutions of the diffusion problem, with coefficients of water diffusion being the same. The mechanism of water diffusion in cartilaginous tissue is also discussed.

[Photochemical reactions in bone tissue induced by excimer laser ultraviolet]. / O proiavleniiakh fotokhimicheskikh reaktsi'i v kostno'i tkani pod de'istviem ul'trafioletovogo izlucheniia eksimernogo lasera.

A phenomenological model of an increase in ultraviolet absorption in bone tissue induced by ultraviolet radiation of excimer laser has been developed. It is assumed that the increase in absorption is related to photochemical reactions in collagen. The model accounts for changes in the intensity of laser radiation due to its absorption inside the specimen. From the comparison of experimental and calculated results the parameters of the photochemical model were estimated. The temperature fields in the specimen were calculated with regard to laser-induced changes in absorption coefficient. The limits of applicability of the model are discussed.

[Possibilities of the use of surgical laser irradiation in spontaneous formation of cartilage tissue in ENT plastic surgery]. / Vozmozhnosti primeneniia izlucheniia khirurgicheskikh lazerov s tsel'iu proizvol'nogo formirovaniia khriashchevoi tkani v plasticheskoi LOR-khirurgii.

The experiments were made to study CO2-laser ability to promote spontaneous formation of nasal septum cartilage. Laser-induced changes in physical and histological characteristics of the cartilage tissue were followed up. Optimal regimens of radiation were selected which allowed to modify cartilage shape without impairment of its morphological and histological structure. In vivo tests were performed on rabbit auricular floor cartilage. The present shape of the cartilage remained stable. It is inferred that laser energy may be a promising tool in plastic ENT surgery.

[Changes in the cartilage shape under the action of laser irradiation]. / Proizvol'noe izmenenie formy khriashcha pod vliianiem lazernogo izlucheniia.

Investigations of structural and mechanical properties of cartilage tissue exposed to laser radiation have shown the effect of laser relaxation of the tension existing in the cartilage and changes in the latter form to be due to phasic transition of water from bound into free state. Laser radiation does not induce macroscopic transformations of the matrix structure. New form of the cartilage proved stable this offering new prospects for wide application of this technique in otorhinolaryngology and plastic surgery.