Volume 53, Nº 3 (2019)

The experience in applying a new method of treating patients with Baker’s cyst is described. The method is based on laser-induced thermotherapy using a special dual-port introducer. It has been shown that the use of the developed surgical instruments makes it possible to reduce the time and cost of the procedure and to increase its safety. It also allows the period of rehabilitation to be reduced in comparison with the conventional surgical methods of treatment. Based on the results of the application of the new method and equipment, practical recommendations have been formulated that make it possible to individualize the treatment of patients with Baker’s cyst.

The number of cases with extensive and complex bone defects undergoing revision endoprosthetization continues to increase. We tested a reendoprosthetization method for hip joints with severe bone tissue deficits using individualized endoprosthesis components in four patients. Clinical data showed that use of a personalized approach to reendoprosthetization of hip joints with severe bone tissue deficit provided complete filling of defects in the acetabulum.

The hemocompatibility of Sputnik rotary blood pumps of the first and second generation (Sputnik-1 and Sputnik-2) was studied using numerical simulation. The influence of the flow geometry on scalar shear stresses (SSS), the residence time, and the volume of recirculation zones was determined. Volume fractions of SSS were obtained for the threshold stress levels of 9, 50, and 150 Pa at a fixed pump speed of 8000 rpm (mean flow rate, 4.5 L/min; pressure, 80 mm Hg). At all selected threshold stress levels, the elevated SSS volumes for the first-generation rotor pump were found to exceed those for the second-generation pump. Thus, the latter has a lesser effect on blood cells. The average residence time was found to be 39 and 29 ms for the Sputnik-1 and Sputnik-2 pumps, respectively; the respective recirculation zone volumes were 4.36 and 1.72 mL. The lesser volume of recirculation zones for the second-generation rotor pump reduces the probability of formation of stagnation zones and, therefore, the probability of clotting. The simulation results showed that upgrading the design of the Sputnik rotor pump had a positive effect on its hemocompatibility.

In this work, the bioavailability of calcium and phosphate from the surface of rods with calcium phosphate coatings applied using different techniques was studied. It was shown that the amounts of released osteotropic elements depend on the coating technique. The differences in the bioavailability of calcium and phosphate should be taken into account in compiling the indications for use of implants coated using different application techniques.

The development and investigation of biosensors for the early and rapid diagnosis of a wide spectrum of diseases to provide significant reductions in mortality and loss of working time as a result of timely treatment is a current challenge in many countries. The active progress in biosensor technology is promoted by the fact that it is an interdisciplinary field exploiting advancements in very diverse areas of knowledge: from physiology to nanotechnology and electronics.

Assessment of the signal-to-noise ratio as a control parameter for magnetic resonance imaging (MRI) systems is addressed. Experimental data were used to run a statistical analysis of noise components. Use of a multichannel radio-frequency receiver coil and determination of the coefficient of correction provided the basis of a method for assessing the signal-to-noise ratio of MRI scans.

Clutter filtering plays an important role in constructing a quality color flow map in ultrasound Doppler imaging. Signals from slow-moving tissues and vessel walls are clutter as they often mix with reflections from blood and should be suppressed for the further correct estimation of flow parameters. Their complete suppression in color flow imaging is difficult, because these signals on average are 40-60 dB more powerful than the signals from blood, the length of the Doppler sequence is very short, and there is always a demand for a real-time operation. This article provides a general model of the Doppler signal and discusses filters based on polynomial and adaptive regression, empirical mode decomposition, and prospective combined approaches to blood flow filtering.