Welding Of Biological Tissues Research Articles

Effect of preloading force on capability of laser welding for skin tissue

Laser assisted suture has become a focus in surgical suture research due to its many advantages, but the current research on the details is not deep enough. To improve the strength and quality of laser biological tissue welding and increase the success rate of penetration in the thickness direction, the effect of external restraint force on the laser tissue welding was explored, and the effect of external restraint force on the optical properties of skin tissue was analyzed. In this study, a Nd:YAG pulse laser was used to conduct welding experiments on the skin in vitro. The laser of 10 W scanned the tissue incision along a linear trajectory. The welding effects under different compression forces and stretching forces were compared. Under the effect of compression force, the skin tissue incision has improved the absorption of laser, and achieved good suture of the incision. The maximum tensile strength can reach 15.56 ± 0.61 N/cm2.The results show that the external preloading force have a significant effect on the strength of the tissue under laser welding. The optical properties of skin tissue under different forces were tested, proving that compression force changes the absorption rate of skin tissue to laser, thereby promoting the photothermal conversion efficiency and improving the welding strength. The stretching force changes the thickness of the tissue, making it easier for the laser to penetrate. At the same time, the tissue is closely attached to achieve effective contact and improve the success rate of welding. The matching combination of preloading force and laser process parameters can achieve high strength with low thermal damage.

New algorithms of high-frequency welding of biological tissues

New algorithms of high-frequency welding of biological tissues

Нові алгоритми високочастотного зварювання біологічних тканин

Нові алгоритми високочастотного зварювання біологічних тканин

МОДЕЛЮВАННЯ АНІЗОТРОПІЇ ПИТОМОЇ ЕЛЕКТРОПРОВІДНОСТІ БІОЛОГІЧНОЇ ТКАНИНИ, ЯКА ВИНИКАЄ ЗА ЛОКАЛЬНОГО СТИСКАННЯ ЕЛЕКТРОДАМИ ДЛЯ БІПОЛЯРНОГО ЗВАРЮВАННЯ

Current publications on bipolar welding use the electrical characteristics of uncompressed biological tissue. This reduces the accuracy of calculating the distribution of the density of the flowing currents and the strength of the electric fields in the zone of the fabric to be welded when it is squeezed. The aim of the work is to show a methodology for calculating the change in the specific electrical conductivity of biological tissue under local compression by electrodes and the effect of this factor on the results of modeling electrical processes of biological welding. A geometric interpretation of the change in the electrical conductivity of the pig's heart muscle when squeezed by bipolar welding electrodes in relative units is proposed. The principle of similarity of the geometric parameters of the physical experiment and the graphic model of COMSOL multyphysics is used, as a result of which the dependences of the three main geometric parameters of the model on the magnitude of the relative compression are determined. The method of successive approximations of the values of the total electrical resistance of biological tissue in a physical experiment at frequencies of 0,3, 30, and 300 kHz and the calculated resistances on the model with a change in the basic geometric parameters of specific electrical conductivity was used. A model of bipolar welding of biological tissues is obtained, which takes into account the anisotropy factor of the electrical conductivity of biological tissue under compression. Some results of investigations of the regularities of the current flow in the tissue, taking into account the arising anisotropy, are presented. References 12, figures 5, tables 4.

Effect of welding temperature and protein denaturation on strength of laser biological tissues welding

The immediate closure of wound has always been a research hotspot in the field of surgery. Compared with traditional suture, laser biological tissue welding has the following advantages: short operation time, fast wound healing, less tissue damage, no suture removal process. In order to improve the strength and quality of laser biological tissue welding, the tensile strength and denaturation degree of skin tissue under different welding temperatures were studied, and the influence of temperature on the welding strength of biological tissue during the welding process was explored, so as to establish the relationship model between welding temperature and tensile strength. The mechanism of weld strength generation was described. The results show that protein denaturation is an important factor for the formation of welding strength in the process of laser biological tissue welding. When the welding temperature is approaching 55 °C, the welding strength is the highest. While the welding temperature reaching 65 °C, the denaturation degree of protein is too large and the tensile strength decreases.

Numerical calculation of laser welds nanocomposite formation parameters for solders based on proteins and carbon nanotubes

Laser welding is an alternative method of biological tissues joining. One of the actual tasks of laser welding of biological tissues is to determine the weld depth by a noninvasive method during surgery. The paper presents a model for calculating the duration of the formation of welds depending on the density of laser radiation power and the depth of the joint. The calculations were performed for the laser beam diameter d = 1.1 mm, power density in the range from 10 to 25 W cm1, weld formation depth l in the range from 0.2 to 1 mm and solders based on aqueous dispersions of bovine serum albumin, indocyanin green and single-walled carbon nanotubes.

Surgical Treatment of Chronic Tonsillitis

The use of diathermy or coblation for both tissue dissection and hemostasis reduced primary bleeding but increased the risk of secondary bleeding compared with traditional tonsillectomy.The objective: was to increase the effectiveness of surgical treatment of children with chronic tonsillitis.Materials and methods. We observed 75 children with chronic tonsillitis between the ages of 6 and 17 under our observation. There were52 in the main group,23 in the comparison group. During tonsillectomy, bipolar instruments and the mode of operation of the high frequency current generator «manual welding» («overlap») with a current frequency of 66 kHz or 440 kHz were used in the main group.Results. With tonsillectomy using high-frequency current, intraoperative blood loss was 6,0±0,440 ml, while during tonsillectomy by the traditional method, intraoperative blood loss was 32,48±1,781 ml (p<0,001) (blood loss when using high-frequency current was 5,4 times lower). The time of tonsillectomy is reduced by 2,1 times. The manifestations of local tissue reaction after tonsillectomy with and without the use of electrothermal adhesion are not significantly different, except for sore throat.Conclusions. The use of high-frequency bipolar welding of biological tissues with the use of developed bipolar power tools for tonsillectomy significantly improves the quality of operations, namely, blood loss during tonsillectomy is reduced by 5,3 times (p<0,001), the duration of surgery is reduced by 2,1 times. Secondary bleeding was not observed in patients using the proposed procedure. The manifestations of local tissue reaction after tonsillectomy with and without the use of electrothermal adhesion are not significantly different.

Effects of scanning paths on laser welding

Laser biological tissue welding is a potential alternative technology from traditional suturing skills. In this study, we explored the influence laws of laser scanning path on in-vitro skin tissue performance and designed four different scanning paths, including heartbeat, circle, peano20-2, and toothed paths. Then the influence laws of laser scanning paths on temperature distributions, mechanical properties and microstructure characteristics were discussed based on the simple factor design of experiments. The samples under the heartbeat path reached the highest peak temperature and the highest tensile strength, but possessed sparse microstructure. The peak temperature of the samples under the circle path was close to that of the heartbeat samples but the tensile strength was only 8.667 N/cm2. The temperature of the toothed samples was much lower and obviously fluctuated. The toothed samples had very bad mechanical properties, but had uniform microstructure. The Peano20-2 samples achieved the best comprehensive microstructure characteristics and tensile strength was up to 19.939 N/cm2 and suffered no color deepening or scars at the macroscale.

Vladimir Ivanovich PETROV-surgeon, scientist, rector
 (to the 95th of birthday)

Vladimir Ivanovich Petrov was born in 1925 in Saransk. After graduation he works as a teacher of physical education and drawing. In 1942 he was drafted into the Red Army. At the time of evacuation of replenishment Vladimir Ivanovich was shell-shocked and got to hospital. After his recovery he fought on the Samland Peninsula, then in the Baltic States, East Prussia, where the assault on the city of Koenigsberg was wounded and received a disability group II. In 1945 V. I. Petrov entered the 1st Moscow medical Institute named after I. M. Sechenov, which he graduated from in 1951. In 1959, Vladimir Ivanovich defended his candidate's thesis, in 1970 his doctoral thesis. In 1974-1987 rector of the 1st Moscow medical Institute named after I. M. Sechenov. Corresponding member of the USSR Academy of Sciences (1978). V. I. Petrov was engaged in the development of repeated operations on the lungs; he was the first to apply the method of ultrasonic cutting and welding of biological tissues in pulmonology, developed the principles of using ultrasound for pneumolysis, lung decortication, scar dissection during operations on the ribs, longitudinal sternotomy, with pleural empyema, treatment of the abdominal cavity. It is also known scientific work on the treatment of atherosclerosis, wasreally hypertension and endarteritis. In 1972 he was awarded the State prize of the USSR. V. I. Petrov is the author of more than 200 scientific works, including 4 monographs, 18 copyright certificates and three foreign patents. Under his leadership, 26 theses on medical and medical-technical subjects were defended. He was awarded the order of Lenin, the October Revolution, the Patriotic war I degree (1945, 1985), the red banner of Labor, "Badge of Honor" medal "For the capture of Koenigsberg" and 12 medals, the sign "Honorary inventor of the USSR." Vladimir Ivanovich died in 2001. About his life and work made a documentary film "Surgeon, scientist, rector" (1983).

Optimization of processing parameters of laser skin welding in vitro combining the response surface methodology with NSGA- II

ObjectiveThis study aimed to optimize the parameters of laser skin welding by combining the response surface methodology with NSGA-II, so as to achieve the goal of improving the weld strength while causing as little thermal damage as possible. MethodsThe response surface methodology was used to design the experiment. The optimization model of laser biological tissue welding process parameters was established, which took the power, pulse frequency and scanning speed of the laser as the optimization variables, the maximum tensile strength of the incision and the peak temperature of skin tissue as the optimization objectives. Meanwhile, the multi-objective NSGA-II algorithm was used to find the optimal solution and obtain the optimal process parameters. Then we carried out experiments to verify the effect of the optimized parameters by comparing with the unoptimized result. ResultsThe optimized process parameters of laser skin welding were effective to improve the welding quality and achieve full-thickness penetration of the skin tissue. Compared with the non-optimized groups, on the premise of guaranteeing maximum strength, the peak temperature of tissue is reduced. ConclusionsUsing the optimized process parameters to weld the skin tissues can obtain higher welding strength and at the same time cause low levels of thermal damage. This also verifies the correctness of the model, which is helpful to improve the adaptability of laser welding to other different tissues and reduce the consumption of time and material.

Investigation of the effect of coagulation with high-energy methods of hemostasis implementation on the resected liver surface (experimental research).

The peculiarity of using high-energy methods to implement hemostasis is in difficulty of comparing the degree of exposure to high temperature with the achievement of the desired effect, at the same time, excessive temperature in the area of impact leads to the formation of a layer of carbonized tissues or their evaporation. In order to analyze the peculiarities of changes in the liver parenchyma after coagulation with high-energy methods of hemostasis, an experiment that provided liver resection with coagulation of the resection surface using convection-infrared thermosurgical technology in a temperature mode of 600°C, bipolar electro-coagulation and high-frequency electric welding of living biological tissues was performed. The study analyzed the results of experimental studies on 25 outbred rabbits of different sex and age, weighing from 3350.0 g to 4180.0 g. Depending on the use of the high-energy coagulation method, 3 groups were formed: group 1 - high-frequency electric welding of living biological tissues; group 2 - bipolar electro-coagulation; group 3 - convection-infrared thermo­surgical technology at a temperature mode of 600°C. The data of histological research were analysed. Statistical analysis was performed using SPSS Statistics. Studies have found that the average trend of the thickness of the disaggregation/disintegration zone is 1936 (1630.83-2523) μm in the 1st group, 648 (508.33-734.33) μm in the 2nd group and 470.6 (453.5-507) μm in the 3rd group. The zone of compacted parenchyma: the 1st group – 2732 (2591.5-2798.5) μm, the second group 4538 (4421.5-4687.5) μm (p=0.001). The results of the study indicate that the use of convection-infrared thermosurgical technology in a temperature mode of 600°C has a less destructive effect on the surrounding tissues as compared with bipolar electrocoagulation and high-frequency electric welding of biological tissues.

Дискуссионные вопросы высокочастотной электросварки биологических тканей

Цель. Исследование физических свойств составляющих биологических тканей и их роли в процессе электрической сварки мягких биологических тканей, а также измерение температуры в зоне электросварки.
 Материалы и методы. Исследования провели с использованием созданной системы для измерения температуры, состоящей из усилителя термо-ЭДС, внешнего модуля АЦП Е14-440 “Л-Кард”, ноутбука с программным обеспечением “PowerGraph”. Использовали также биполярный электрохирургический зажим и ВЧ-электрокоагулятор ЕК-300М1. Для имеющегося при сварке биологических тканей диапазона температур 40 – 200 °С выбраны термопары К–типа диаметром 70 мкм.
 Результаты. Проведенные исследования позволили установить, что сопротивление электролитов уменьшается, а проводимость - увеличивается с повышением температуры. Это объясняется тем, что с повышением температуры для слабых растворов увеличивается их диссоциация и, следовательно, число положительных и отрицательных ионов. Электропроводность цельных органов в 2 - 5 раз ниже, чем электропроводность биологических жидкостей. Поэтому при «полном» обезвоживании ткань практически теряет электропроводность, тепло в ней перестает выделяться и происходит резкое падение напряжения, силы тока и сопротивления, что предотвращает глубокие деструктивные изменения мягких тканей в зоне электросварки. Эти данные получены нами в процессе выполнения эксперимента по изучению температурных режимов тканей кишечника, мышечной ткани, легкого и печени.
 Выводы. Данными, полученными в ходе выполнения эксперимента, доказана безопасность высокочастотной электросварки мягких тканей в пределах температурных режимов от 45 до 95 °С без явлений некроза и обугливания.

Innovative technologies in vascular surgery

The aim — to search for new diagnostic and therapeutic directions in vascular surgery and study their technologies via experimental and clinical researches.Materials and methods. 1) The temperature during electric welding of biological tissues ranged from 4 to 146 °C, the average operating temperature during the welding process was 88.4 0C. The noise filtering was performed using noise filter functions and a LowPass FIR filter with the 20 Hz frequency. Histological specimens were studied using the Olympus BX 51 microscope, the Olympus C5050 Z digital camera, and the Olympus DP­Soft software. 2) MRI was performed in order to determine the actual shape of the vessels. For the reconstruction of their spatial shape, 3D image reconstruction software MRI Invesalins was used. The solid model of the artery was created using a laser 3D printer. Graph­analytical methods were used to describe the shape of the compressed artery. 3) The polymorphism of the NOS3 gene (the single nucleotide genetic polymorphism (SNP) in the human reference sequence — rs1799983) and the polymorphism of the CRAT gene (SNP in the reference human sequence — rs2296771) were identified by real­time polymerase chain reaction. The amplification of a corresponding region of DNA with a standard set of primers using the phenomenon of energy transfer using fluorescence resonance (FRET) was conducted in order to identify the polymorphic alleles.Results and discussion. 1) The electrowelding of the artery wall between the electrodes formed a seam, which consisted of a dense semitransparent tissue of light brown color with a clear boundary along the edge of the electrodes location. Microscopically, the substance of the electrowelding seam was represented by a homogeneous dense substance, which consisted of coagulated and strongly interconnected protein structures of vessel wall collagen fibers. 2) 3D reconstruction of the cervical arteries was performed using the 3D image reconstruction program MRI Invesalins, which objectively displayed the condition of the vertebral artery at the site of its narrowing. Reconstruction of the spatial shape of the artery made it possible to create the artery solid model using a laser 3D printer. 3) Based on the results of the genetic studies, a group of patients with a predisposition to develop endothelial and mitochondrial dysfunction was identified, where Tivorel (4.2 g arginine hydrochloride + 2.0 g L­carnitine) was used. Endothelial function in this group of patients was assessed by the magnitude of flow mediated vasodilatation (FMD), which reflects the ability of the brachial artery to dilatate in response to ischemia induced hyperaemia. The use of L­arginine resulted in a statistically significant increase in the flow mediated vasodilatation (FMD), which indicated the restoration of impaired endothelial function.Conclusions. 1) The strength of the tissue connection in electric welding seam depends on the degree of the tissue homogenization. 2) Graphical 3D modeling of pathologically narrowed arteries and computer data processing of MRI of the vessels allows determining the localization, character and spatial characteristics of the artery extravasal compression. Graph­analytical methods for describing the arterial shape became the theoretical basis for a new method of the artery extravasal compression studying. 3) The basis of personalized treatment in patients with ischemic tissue lesions is the conduction of genetic studies. Especially the determination of single nucleotide genetic polymorphisms (SNP) of the NOS3 gene, that is responsible for the synthesis of the protein «endothelial nitric oxide synthase» (rs1799983), and gene CRAT, that is responsible for the synthesis of the protein «carnitine­O­acetyltransferase» (rs2296771), is needed. Identification of mutant homozygotes determines predisposition to endothelial and mitochondrial dysfunction of the vessels, the development of atherosclerosis, arterial hypertension, diabetes mellitus, and heart failure.

RECONSTRUCTIVE ONE- AND TWO STEP JEJUNOGASTROPLASTY AFTER TOTAL GASTRECTOMY IN BLEEDING GASTRIC CANCER

Relevance. Modern and topical questions of surgical treatment of acute bleeding gastric cancer are considered with the use of innovative hardware technologies of operative interventions with the formation of an artificial ventricle (jejunogastroplasty) after total gastrectomy (GE).
 Objective. Development and introduction of new technologies and methods of one-stage and two-stage reconstructive jejunogastroplasty (JGP), which can improve the functional results of total gastrectomy for acute bleeding gastric cancer.
 Materials and methods. Are analyzed 30 patients after the GE in conjunction with jejunogastroplasty (JGP) for bleeding gastric cancer. Men were 22 (73 %), women – 8 (27 %). In 68 % of patients who underwent JGP verified III st. and IV st. neoplastic process. When forming an artificial stomach (reconstructive JGP) used a variety of options and technologies: JGP manually performed in 3 (10 %), hardware – in 27 (90 %).
 Results. JGP by Roux loop applied in 6 (20 %), Ω-loop JGP with Brownian anastomosis – in 16 (53 %), and in 8 (27 %) performed reconstructive hardware JGP in a functionally advantageous embodiment including of the duodenum. In 28 patients lymph node dissection performed in the amount of D2, two – D1 using an ultrasonic scalpel and the machine welding of biological tissues. Deaths were not. Developed and implemented the concept two-step JGP after total GE at bleeding gastric cancer. In the first phase, the GE with lymph node dissection. In developing dumping syndrome, nongastric fatigue, weight loss, violation digestiv tract function in the postoperative period and in the absence of data on the progression of the tumor process in the second phase after 4-6 months (sometimes 1-1,5 years) after total GE undertaken reconstructive JGP with the creation of artificial jejunum reservoir. Developed sixteen variants hardware reconstructive JGP without including and with the including of the duodenum in the digestive transit. The best functional results obtained after reconstructive JGP including of the duodenum.
 Conclusions. In patients young and middle age after total GE at bleeding gastric cancer it is advisable to complement perfoming JGP including of the duodenum. The use of one- and two step JGP after total GE improves the quality of life of the patients in the late postoperative period.

Simulation of the effect of spot size on temperature field and weld forming in laser tissue welding

Laser Biological Tissue Welding is a great potential for tissue suture replacement technology. However, most of the biological tissue laser welding research focused on the chronic histology after laser irradiation, the lack of systematic analysis of laser parameters and other related factors on the impact of tissue welding anastomosis effect. In this work, in order to understand the heat transfer and heat distribution, a two-layer structure model of skin was developed and validated with the experimental results, which is based on the theory of bio-heat transfer. Under the condition of different spot sizes, the temperature response of the model, including the peak temperature, the temperature field distribution and the time behavior, were calculated according to the Gaussian distribution laser heat source. We evaluated the effect of changes in laser spot size on the thermal denaturation zone produced during laser skin welding. The calculated result basically in good agreement with the experimental result indicated that the developed model was validity and reasonable.

Use of Indocyanine Green in Nanocomposite Solders to Increase Strength and Homogeneity in Laser Welding of Tendons

The ability to form sutures in bovine tendon using a prototype laser biological tissue welding device was demonstrated. New solder compositions are proposed, based on carbon nanotubules (0.1% w/w) in an aqueous matrix of bovine serum albumin (25% w/w) supplemented with the medical laser dye indocyanine green (0.01% w/w). The absorption peak of the nanocomposition solder coincided with the apparatus wavelength of 800 nm. The use of indocyanine green as radiation absorber in nanocomposition solders provided increases in the strength of laser weld sutures in tendons. The maximum level of ~0.82 MPa was achieved using a solder based on multiwalled carbon nanotubules. X-Ray microtomography demonstrated uniformity in the joining of tendons in depth and length during formation of nanocomposite between the two welded biological tissue fragments. Growth of fibroblast cells on the composite surface formed at the site of the laser weld suture was demonstrated.

Стендовые исследования высокочастотной электросварки биологических тканей

Стендовые исследования высокочастотной электросварки биологических тканей

Bench research of high-frequency electric welding of biological tissues

Bench research of high-frequency electric welding of biological tissues

Поєднання лапароскопічних та електрозварювальних технологій у лікуванні хворих з гострим апендицитом як фактор профілактики інтраабдомінальних ускладнень

У роботі проаналізовано результати операційного лікування 96 хворих із гострим апендицитом. Серед пацієнтів переважали жінки – 54 (56,3 %). Всім хворим виконували лапароскопічну апендектомію як під загальною анестезією, так і регіонарним знеболюванням. Хворим основної групи обробку брижі та формування кукси червоподібного відростка виконували методом зварювання живих тканин. У контрольній групі обробку брижі здійснювали традиційною коагуляцією та кліпуванням, а формування кукси проводили лігатурним методом, з обробкою її монополярною коагуляцією. При мікробіологічному дослідженні із кукси червоподібного відростка в основній групі пацієнтів росту мікроорганізмів не виявлено у 100 %, в контрольній групі після обробки кукси монополярною коагуляцією у 9 (27,3 %) виявили помірний бактеріологічний ріст (p>0,05). Інтраабдомінальних ускладнень в основній групі не виявлено, в контрольній діагностовано інфільтрат у правій здухвинній ділянці без клінічних проявів у післяопераційному періоді у 4 (12,1 %) пацієнтів (p>0,05). Медикаментозне лікування пацієнти основної групи отримували 1–2 дні (p<0,05), контрольної 3–4 дні. Середній ліжко-день в основній групі склав (1,5±0,5) доби (p<0,05), в контрольній – (3,0±0,5) доби. Поєднання лапароскопічних та електрозварювальних технологій у лікуванні хворих з гострим апендицитом характеризується зменшенням ризику виникнення післяопераційних інтраабдомінальних ускладнень або повною їх відсутністю, меншим больовим синдромом у післяопераційному періоді, коротким періодом стаціонарного лікування та швидкою реабілітацією.

Сравнительная эффективность витректомии с использованием для ретинопексии высокочастотной электросварки биологических тканей и диодной лазерной коагуляции в лечении больных регматогенной отслойкой сетчатки

Сравнительная эффективность витректомии с использованием для ретинопексии высокочастотной электросварки биологических тканей и диодной лазерной коагуляции в лечении больных регматогенной отслойкой сетчатки