Thermic effects in the "vestibule" during laser stapedotomy with pulsed laser systems.

Background And Objective: Apart from the ablation properties at the stapes footplate, the degree of thermic loading in the inner ear is important in determining the suitability of pulsed lasers for stapedotomy. The aim of the study is to compare the thermic effects in the vestibule with different pulsed laser systems.

Study Design/materials And Methods: Temperature increases and heat exchange processes in the fluid (physiological saline) were examined in a calorically and physiologically approximated cochlea model for applying the laser parameters effective in creating footplate perforations.

[The development of a finger joint phantom for the optical simulation of early inflammatory rheumatic changes].

In the field of rheumatology, conventional diagnostic methods permit the detection only of advanced stages of the disease, which is at odds with the current clinical demand for the early diagnosis of inflammatory rheumatic diseases. Prompted by current needs, we developed a finger joint phantom that enables the optical and geometrical simulation of an early stage of rheumatoid arthritis (RA). The results presented here form the experimental basis for an evaluation of new RA diagnostic systems based on near infrared light.

Effects of pulsed laser systems on stapes footplate.

Background And Objective: The aim of the present study was to investigate the tissue ablation capacity of various pulsed lasers at the stapes footplate.

Study Design/materials And Methods: Isolated human stapes and bovine compact-bone platelets were used to determine the effective laser parameters and appropriate application technique for achieving a perforation measuring 500-600 microns in diameter. Of interest were also the shape and quality of the perforations, the reproducibility of the perforation effect, and the thermically altered marginal zones occurring at the footplate.

Effects of continuous-wave laser systems on stapes footplate.

Background And Objective: The aim of the present study was to clarify which of the presently available continuous-wave laser systems are best suited for application in stapes surgery.

Study Design/materials And Methods: Isolated human stapes and bovine compact-bone platelets were used to investigate the connections between the parameters of various laser systems and their effects on bone tissue. The purpose was to optimize the laser parameters required to achieve a perforation measuring 500 microns to 600 microns in diameter.

In vitro studies and computer simulations to assess the use of a diode laser (850 nm) for laser-induced thermotherapy (LITT).

Background And Objective: This study investigated the feasibility of 850 nm diode laser-induced thermotherapy (LITT), a new procedure providing local hyperthermia and photocoagulation, a minimally invasive treatment of tumors, and other disorders such as benign prostate hyperplasia.

Study Design/material And Methods: An improved fiber optic diffuser inserted through a catheter was used to irradiate prostate, liver, and kidney tissue in-vitro. Experimental results were compared with predictions from mathematical simulations based on measured optical tissue parameters.

[Thermal stress on the inner ear in laser stapedotomy].

Apart from ablation properties at the stapes footplate, the degree of thermal stress of the inner ear is important when considering the suitability of pulsed lasers for stapedotomy. The aim of the present study was to compare the heating of cochlear structures with presently available pulsed laser systems during stapedotomy under reproducible conditions. Temperature increases and heat-exchange processes were examined in a physiologic model of the cochlea using various laser parameters effective for footplate perforations.

[Thermal stress of the inner ear during laser stapedotomy. I: Continuous-wave laser].

As a consequence of perforating the footplate during laser stapedotomy, direct radiation to the inner ear will warm perilymph and adjacent structures. To determine the possible thermal dangers to cochlear structures from different laser parameters, heat transport mechanisms, temperature increases and temperature fields were investigated in a model system approximating caloric and physiologic changes in the inner ear. The temperature-time course of local cochlear warming showed a rapid convection-dependent increase that reached a peak at about the end of the laser impulse.

[In vitro studies of the specifications for methodological and technical equipment requirements of endoscopic infrared diaphanoscopy].

Endoscopic infrared diaphanoscopy is a method of improving orientation in the nasal cavity during endoscopy-controlled endonasal surgery. The transillumination is expected to facilitate the localisation of the natural passageways between the paranasal sinuses and the nasal cavity during endoscopic procedures. The present study specifies the necessary conditions on the basis of in vitro examinations using an animal model (sheep) and an anatomical preparation of half of the human head.

[Modifying the stapes footplate with various laser systems. II. The pulsed laser].

The object of the present study was to examine the tissue ablation capacity of various pulsed lasers at the stapes footplate. Isolated human stapes and bovine compact-bone platelets (thickness 90 microns) were used to determine effective laser parameters for achieving a perforation measuring 500 microns to 600 microns in diameter. Apart from achieving the perforation diameters, particular attention was given to the form and quality of the perforations, reproducibility of the perforation effect and the thermally altered border zones occurring at the footplate.

[Revision of the stapes foot plate with various laser systems. 1: Continuous laser irradiation].

During stapedotomy, the small dimensions and highly sensitive anatomic structures present require the highest degree of precision and safety. The risk of damage to middle and inner ear structures through manipulation with conventional instruments can be reduced by non-contact perforation of the footplate with the laser beam. The present study was devised to clarify which of the presently available laser systems was best suited for use in stapes surgery and thus represent a significant alternative to conventional stapedotomy.