Development of a device for safe spatial orientation of the spokes of an extra-focal osteosynthesis apparatus

A special place in the methods of surgical treatment of bone fractures is occupied by transosseous osteosynthesis using external fixation devices.The aim of the study is to develop a device for the safe spatial orientation of the wires of the extrafocal osteosynthesis apparatus.Materials and methods. To develop a device for the spatial orientation of the external fixation spokes, a 3D model was designed with further reproduction on a 3D printer. The development of the device was carried out by placing the wires of the external fixation apparatus on 36 bones of the human lower jaw, on which a fracture in the angle was simulated.Results and discussion. The device for the spatial orientation of the spokes of the external fixation device for the lower jaw exoselet is partially reproduced using a 3D printer, which allows individualizing the device parts at the stages of preparation for surgery.Conclusions. Effect: control of the depth of immersion of osteofixers over the entire thickness of the bone and simplification of the choice of the optimal angle of mutual spatial orientation during their introduction and the greatest stable fixation of the fragments of the lower jaw during closed extrafocal osteosynthesis.

Experimental modeling of deforming osteoarthrosis of the knee in small rodents

The results of experimental work on modeling deforming osteoarthrosis of the knee joint in small rodents are presented. The pathogenetic basis of this process is a violation of the blood supply and the distribution of physiological load in the joint. Variants of rigid and non-rigid limb immobilization systems are proposed. The results of morphofunctional assessment are given, indicating a violation of the anatomical and histological structure of the metaphysis, pineal gland and metaepiphysis of the femur and tibia. The leading role in the development of deforming osteoarthritis of the knee belongs to the violation of the physiological distribution of the dynamic load on the joint, and the most vulnerable to the progression of this process are subchondral structures. Violation of regional blood circulation of the lower limb of the animal was achieved by crossing the femoral artery. Limb immobilization was carried out for 4 weeks. The results were evaluated by the severity of changes in the morphological structure of the operated joints and radiographic examination. The high mitotic activity of cellular elements, revealed as a result of histological examination in all groups of animals, indicates the rapid formation of vascular collaterals in rats. It was noted that with non-rigid immobilization of the joint with a plaster cast, the cartilaginous tissue of the articular surface becomes thinner, while the subchondral structures change slightly. With severe immobilization of the joint in the external fixation apparatus, significant changes are revealed precisely in the structure of subchondral structures. In animals subjected to a two-week rehabilitation period after dismantling the external fixation apparatus, a further progression of the pathological process was noted. Thus, with severe immobilization of the limb in the experiment, it was possible to obtain a stable joint deformation corresponding to the 3rd clinical and radiological stage of osteoarthritis.

Growth regulators – a biological means for stimulating photosynthetic activity, nitrogen fixation and the increase of the biological value of protein in forage peas (Pisum arvense L.)

The aim of the study was to determine the effect of foliar application of growth regulators on photosynthetic activity, nitrogen fixation and the biological value of protein in two cultivars of winter forage peas – Mir and Vesela. For achieving the aim set, a three-year field trial was carried out in the Training and Experimental Fields of the Agricultural University of Plovdiv, on a plot untreated with commercial fertilizers. The following growth regulators were used: RENI, RENI D, Bormax, Manganese Chelate and Molybdenite, applied at the phenological stage of pea plant budding. The effect of those products on the studied characteristics was compared to the untreated control. The reported three-year results show that foliar applied growth regulators had a positive effect on photosynthetic and nitrogenase activity, as well as on the characteristics of the nitrogen fixation apparatus (total number of nodules, number of active nodules and weight of the nodules) and on the biological value of the obtained protein in both cultivars of winter forage peas.

Percutaneous puncture nephrostomy on the back of a patient with an external fixation apparatus on the bones of the pelvis following a road traffic accident

The article presents a rare clinical case of renal colic with a stone in the lower third of the ureter in the patient after a traffic accident with an external fixation device on the pelvic bones. A 41-year-old patient was hospitalized to the emergency urology department of the City Hospital No. 5 of Naberezhnye Chelny in 2019 with renal colic on the right. An ultrasound revealed right pelvocaliectasis of kidney. Pelvic survey (urogram) shows the shadow (9 mm in diameter) suspicious for renal calculus in the projection of the lower third of the right ureter. The pain was not relieved by analgesics. It was unsuccessfully attempted to stent the right ureter due to insurmountable obstacle at a distance of 4 cm from the ureteral orifice. Due to technical complexity (laying the patient in a lithotomy position and on the stomach or side was impossible due to a possible breakdown of the external fixation apparatus on the pelvic bones) percutaneous puncture nephrostomy was performed under ultrasound control in the supine position according to emergency indications. The pain was relieved. The patient was discharged home. After one month, the external fixation device for the pelvic bones was removed. The patient was hospitalized again. Ureteroscopy and contact ureterolithotripsy on the right ureter were performed routinely. Nephrostomy was removed. The patient recovered. The described case is of clinical interest as a rare combination of renal colic and the presence of an external fixation apparatus on the bones of the pelvis, which causes additional difficulties for the drainage of the urinary tract. Percutaneous puncture nephrostomy on the back with a roller in the ipsilateral kidney is a good alternative for urologists when to lay the patient on the stomach or side is impossible.

The Development and Testing of a Fixation Apparatus for Inducing the Coaptation of the Cardiac Atrioventricular Valves

As the prevalence of mitral and tricuspid valvular disease continues to grow with the aging population [1,2], there is a growing critical need to treat high mortality risk patients using minimally invasive and/or non-surgical percutaneous procedures. However, these transcatheter procedures, especially those aimed at repairing or replacing the mitral and tricuspid valves, are mostly still in development and/or early clinical testing. Catheter delivery, prosthesis fixation, and/or demonstrating device efficacy are major challenges currently being addressed [3,4]. Although in situ animal models can assess catheter systems with clinical imaging, direct visualization of tissue-device interactions in real human heart anatomies are desired. In vitro delivery and implantations of valvular prototypes in human heart specimens can be instrumental for accurate device testing and gaining important design insights. Such investigations can be performed on a pulsatile flow apparatus, utilizing perfusion fixed human hearts with mitral and/or tricuspid valves eliciting coaptation and relative function. The employment of endoscopic cameras provides direct visualization and can be coupled with echocardiography, providing novel insights relative to these transcatheter devices in a dynamic environment. However, these investigative approaches require appropriately fixed human heart specimens that will allow for dynamic valve movement. This study discusses the design, construction, and implementation of a novel fixation apparatus to promote the coaptation of the mitral and tricuspid valves in swine and fresh human heart specimen.

Internal structuring of silica glass fibers: Requirements for scattered light applicators for the usability in medicine

Background:Diffuser fibers have been used for some time in the fields of laser-induced thermotherapy and photodynamic therapy. For their applicability the breaking strength, the thermostability and a homogeneous radiation profile are of great importance. Flexible applicators offer special benefits because they introduce a totally new range of application possibilities.Objective:The aim of the presented investigations was to develop a totally new flexible diffuser fiber generation which can be produced cheaper and without the use of any further materials. For this purpose it was proposed to induce scattering micro dots directly into silica fibers by generating a local change of the refractive index in the core of the optical fiber. The resulting diffuser was expected to create a homogeneous radiation profile containing at least 80% of the light coupled into the optical fiber, i.e. less than 20% prograde (forward) emission.Materials and methods:On the basis of former research results, scattering micro dots were induced linearly into the core of an optical silica fiber through a multiple photon process using a femtosecond laser. In addition to the macroscopic optical control by means of a microscope, the form of the radiation profile was examined as well as the non-scattered forward emission which depends on a variety of influencing factors. The processing was optimized according to the observations made. The thermostability of the developed prototypes was assessed by using a thermocamera, and the minimal bending radius was determined. Finally the prototypes were tested and validatedResults:An influence of the processing power, the number and radial position of the scattering micro dots as well as the therapeutic coupled-in wavelength onto the form of the radiation profile and the non-scattered forward emission was determined. Both the form of the radiation profile and the prograde emission were found to be independent of the therapeutic laser power coupled into the fiber. The developed prototype had a nearly homogeneous radiation profile, a forward emission of 12.8±2.1% in average, and a minimum bending radius of 31±6 mm.Conclusion:The non-scattered forward emission of the developed diffusers was within the objective of below 20% and the radiation profile was very nearly homogeneous. In order to improve the reproducibility of the production process, an improved fixation apparatus needs to be developed.

Biochemical substantiation of the number of implants in the mandibular intermental space for fixing an orthopedic device

A biochemical substantiation of the placement and the number of implants in the mandibular intermental space for orthopedic fixation apparatus has been carried out. The study has been perfomed on 54 patients aged from 41 to 86 year(23 men and 31 women) with complex maxillofacial pathology who were introduced into the edentulous mandible 207 implants of wich 187 being single-stage uncollapsible and 20 being two-stage collapsible ones. It has been corroborated biochemically that an adequate functioning of the orthopedic apparatus depends on the number of abutment fixation elements, whereas the number of implants and variants of their placement plants upon a specific clinical situation.