Tissue Welding Research Articles

Finite element simulation and experimental validation of thermal damage to isolated porcine skin tissue by femtosecond laser welding.

The welding effect of the laser on skin tissue is reduced by thermal damage to skin tissue, and greater thermal damage to skin tissue caused by the laser is prevented by predicting thermal damage. In this paper, a finite element model is established for the temperature field of skin tissue scanned by a femtosecond laser to obtain the influence of laser process parameters and scanning path on the thermal damage parameters of skin tissue and the thermal damage area, and verified experimentally. The results show that the established finite element model is accurate and can accurately reflect the temperature distribution during the process of femtosecond laser welding of porcine skin tissues; used to predict the thermal damage parameters of the skin tissues and the thermal damage area; and provide guidance for the study of the femtosecond laser welding of the skin tissues process to obtain the optimal process parameters.

Development of implantable electrode based on bioresorbable Mg alloy for tissue welding application

An implantable electrode based on bioresorbable Mg-Nd-Zn-Zr alloy was developed for next-generation radiofrequency (RF) tissue welding application, aiming to reduce thermal damage and enhance anastomotic strength. The Mg alloy electrode was designed with different structural features of cylindrical surface (CS) and continuous long ring (LR) in the welding area, and the electrothermal simulations were studied by finite element analysis (FEA). Meanwhile, the temperature variation during tissue welding was monitored and the anastomotic strength of welded tissue was assessed by measuring the avulsion force and burst pressure. FEA results showed that the mean temperature in the welding area and the proportion of necrotic tissue were significantly reduced when applying an alternating current of 110 V for 10 s to the LR electrode. In the experiment of tissue welding ex vivo, the maximum and mean temperatures of tissues welded by the LR electrode were also significantly reduced and the anastomotic strength of welded tissue could be obviously improved. Overall, an ideal welding temperature and anastomotic strength which meet the clinical requirement can be obtained after applying the LR electrode, suggesting that Mg-Nd-Zn-Zr alloy with optimal structure design shows great potential to develop implantable electrode for next-generation RF tissue welding application.

Assessing the influence of parameters on tissue welding in small bowel end-to-end anastomosis in vitro and in vivo.

The use of high-frequency electric welding technology for intestinal end-to-end anastomosis holds significant promise. Past studies have focused on in vitro, and the safety and efficacy of this technology is uncertain, severely limiting the clinical application of this technology. This study investigates the impact of compression pressure, energy dosage, and duration on anastomotic quality using a homemade anastomosis device in both in vitro and in vivo settings. Two hundred eighty intestines and 5 experimental pigs were used for in vitro and in vivo experiments, respectively. The in vitro experiments were conducted to study the effects of initial pressure (50-400kpa), voltage (40-60V), and time (10-20s) on burst pressure, breaking strength, thermal damage, and histopathological microstructure of the anastomosis. Optimal parameters were then inlaid into a homemade anastomosis and used for in vivo experiments to study the postoperative porcine survival rate and the pathological structure of the tissues at the anastomosis and the characteristics of the collagen fibers. The anastomotic strength was highest when the compression pressure was 250kPa, the voltage was 60V, and the time was 15s. The degree of thermal damage to the surrounding tissues was the lowest. The experimental pigs had no adverse reactions after the operation, and the survival rate was 100%. 30days after the operation, the surgical site healed well, and the tissues at the anastomosis changed from immediate adhesions to permanent connections. High-frequency electric welding technology has a certain degree of safety and effectiveness. It has the potential to replace the stapler anastomosis in future and become the next generation of new anastomosis device.

Impact of SWCNTs and CMCS on efficacy of anastomosis and optical properties in vivo during laser biological tissue soldering

In order to improve the mechanical properties of skin tissue incision, enhance laser absorption efficiency, further shorten healing time and reduce skin fibrosis tendency, this study investigated the effects of CMCS or SWCNT combined with 25 % BSA and 0.4 % ICG on laser tissue welding. Nd:YAG pulsed laser was used for wound closure test on live rats with an energy density of 67.3 J/cm2 and linear scanning of skin incisions. The effects of different types and concentrations of biological dressings on wound closure were tested at different sites. The results showed that biocompatible dressings containing CMCS and SWCNTs had a significant effect in promoting wound healing after laser welding. After laser welding, the tensile strength of the control group without CMCS or SWCNTs was only between 6.5 and 9.8 N/cm2, while that with CMCS reached as high as 26.5 N/cm2. Macroscopic morphology analysis showed that components such as CMCS and SWCNTs could significantly shorten healing time from 14 days to 9–10 days. Optical performance tests demonstrated that a combination of 5 %CMCS and 4 %SWCNTs can significantly increase skin's absorption coefficient for laser photons up to7-8 Lg-1cm−1 and reduce photon diffuse reflectance. HE and Masson staining revealed that when internalized by dressing containing 0.4 %SWCNTs, nanocarbon particles promoted collagen skeleton regeneration but increased fibrosis tendency after 14 days post-laser welding, resulting in unfavorable long-term healing outcomes. However, the combination of CMSC with SWCNTs can significantly improve incision mechanical properties, laser photon absorption rate, and shorten healing time while reducing scar proliferation tendencies.

Laser tissue welding by using collagen excitation at a 1,720 nm near-infrared optical window III.

Laser tissue welding (LTW) is a method of fusing incised tissues together. LTW has the potential to revolutionize plastic surgery and wound healing techniques by its ability to produce watertight, scarless seals with minimal foreign body reaction. While using thermal mechanisms to achieve LTW, energy from the incident laser is absorbed by water in the tissue. As the water temperature increases, partial denaturing of the collagen triple helix briefly occurs, which is quickly followed by renaturation of collagen as the tissue cools, thus providing a watertight seal. This research study investigates the efficacy of direct collagen excitation at 1,720nm to accomplish LTW. This wavelength falls within the near-infrared (NIR) optical window III. The tensile strengths of pig skin that have been welded with NIR continuous-wave (CW) diode lasers at 1,455nm, which promote thermal mechanisms of tissue welding, and 1,720nm wavelengths, are compared. Near-infrared lasers tuned to 1,455 and 1,720nm were used to weld incised pieces of porcine skin together without extrinsic solders or dyes. The tensile force of the welded tissues was measured using a digital force gauge. The average tensile force of the welded pig skin using the 1,720nm laser was approximately four times greater than that using the CW 1,455nm laser, suggesting that LTW accomplished through direct collagen excitation in the NIR optical window III provides greater tensile strengths.

Design and simulation of a multi-functional radiofrequency tissue welding electrode

Purpose: To explore the effect of electrode structure on welding quality by modifying the structure of magnesium alloy electrode. Methods: Two novel electrodes were designed in this study, including one with a circle (C) surface and the other with a square and arched (SA) surface. The designed electrodes were compared to a control electrode with a smooth surface in terms of temperature distribution, thermal damage to tissue, and effective welding area. Finite element analysis was used to analyze the stress and strain of all electrodes and thermal damage to the tissue. Results: Pressure applied to the designed electrodes was within the elastic limit, and the deformation was less than 1%. The highest temperature of SA electrode (99.6 ℃) was similar to that of the control (100 ℃), while that of C electrode (106 ℃) was higher than the control. The mean temperature at the welding site in intestine of the control electrode was significantly higher than that of the other two electrodes. Besides, the mean temperature of C electrode was also slightly higher than that of SA electrode. The tissues welded by the control electrode, C electrode and SA electrode were completely necrotic within an axial distance of 2.546 mm, 2.079 mm, and 1.835 mm from the edge of the welding area, respectively. Conclusion: SA electrode has the lowest thermal damage compared with the other two electrodes due to smaller effective welding area. Therefore, SA electrode is better than the other two electrodes.

Microstructure evolution of laser skin tissue welding under the control of energy regulation

Laser skin tissue welding has the advantages of shallow scar and fast recovery due to the use of laser energy to suture skin tissue, and has great application potential in the field of beauty and biomedicine. However, the faster the recovery speed after surgery, the smaller the degree and scope of protein denaturation required, and the suture strength cannot be guaranteed, which makes it difficult to achieve both strength and recovery speed at the same time. Therefore, a laser targeted suture method based on energy regulation is proposed. This method can accurately control the region and extent of protein denaturation, and achieve the highest strength suture under the minimum protein denaturation. In addition, the directional fusion of collagen reticular tissue was achieved by regulating the micro morphology of denatured collagen tissue during the suturing process, and the suture samples meeting the requirements were successfully obtained. The microstructure observation and mechanical property test of the adjusted suture sample showed that the re melted collagen fiber tissue was reticular distribution, similar to the original tissue structure, with good mechanical properties, and the tensile strength reached 41.6 ± 2.5 N/cm2. This makes this method have a great potential application prospect in biological tissue welding application scenarios.

Experimental research on mechanism of collagen remodeling and excellent properties of skin incisions under dual beam laser welding

For problems of water loss caused by rapid energy dissipation and insufficient depth of heat-affected zone (HAZ) during skin welding with single laser beam. A dual beam 1064 nm semiconductor laser was used to weld incisions on the back of porcine skin, and the dual beam laser was consisted of preliminary beam and the secondary beam. The main beam is vertically incident, and the secondary beam is deflected by 30° on a vertical basis. In this study, there are three types of energy ratios of dual beam laser, which are 1:1, 2:1 and 3:1. From 77.22 J/cm2 to 135.4 J/cm2 stepped increasing energy density, the fusion performances of skin incisions after welding were comprehensively analyzed and characterized. Using Matlab and high-precision dynamometer to evaluate thermal denaturation and biomechanical properties, combined with H&E staining, Masson and Sirius red staining to analyze the microstructure characteristics, collagen deposition behavior and distribution around the HAZ of incisions after welding. The results showed that when the energy density was 102.96 J/cm2, at the energy ratio of 1:1, the collagen network structure was dense, collagen deposition was 48 %, thermal damage value was 0.39, and the immediate tensile strength was 206.3 N/cm2, which was far above the standard of wound healing performances after surgical treatment, and the thermal denaturation was controlled at a low level, realizing the reconstruction of collagen after fracture, achieving the optimal dual-beam laser welding performance, in vivo test results found that above laser type and energy ratio can reduce healing cycle into 7 days, which provided important references for later study on laser tissue welding technology.

Evaluation of fusion performances of skin wound incisions under different defocus amounts in laser tissue welding

Evaluation of fusion performances of skin wound incisions under different defocus amounts in laser tissue welding

An ex vivo preliminary investigation into the impact of parameters on tissue welding strength in small intestine mucosa-mucosa end-to-end anastomosis.

Background: Tissue welding is an electrosurgical technique that can fuse tissue for small intestine anastomosis. However, limited knowledge exists on its application in mucosa-mucosa end-to-end anastomosis. This study investigates the effects of initial compression pressure, out-put power, and duration time on anastomosis strength ex vivo in mucosa-mucosa end-to-end anastomosis. Methods: Ex vivo porcine bowel segments were used to create 140 mucosa-mucosa end-to-end fusions. Different experimental parameters were employed for fusion, including initial com-pression pressure (50kPa-400kPa), output power (90W, 110W, and 140W), and fusion time (5, 10, 15, 20s). The fusion quality was measured by burst pressure and optical microscopes. Results: The best fusion quality was achieved with an initial compressive pressure between 200 and 250kPa, an output power of 140W, and a fusion time of 15s. However, an increase in output power and duration time resulted in a wider range of thermal damage. There was no significant difference between the burst pressure at 15 and 20s (p > 0.05). However, a substantial increase in thermal damage was observed with longer fusion times of 15 and 20s (p < 0.05). Conclusion: The best fusion quality for mucosa-mucosa end-to-end anastomosis ex vivo is achieved when the initial compressive pressure is between 200 and 250kPa, the output power is approximately 140W, and the fusion time is approximately 15s. These findings can serve as a valuable theoretical foundation and technical guidance for conducting animal experiments in vivo and subsequent tissue regeneration.

Analytical solution of heat-transfer in central part of tibia bone tissue using non-Fourier heat equation with a laser heat source

Hyperbolic heat transfer equation considering a laser heat source is analytically investigated using Laplace transform method to study the temperature distribution in the central part of the tibia bone tissue. The target zone is the compact layer of tibia, and the laser irradiation in four near-surface points during 2 s is taken into account. Holmium–Yttrium–Aluminum-Garnet (Ho-YAG) laser is utilized in the simulations. Results indicate that there is a trilateral relationship among the temperature changes of various points in the tissue, the power used and the wavelength. While neglecting the effects of blood circulation upon laser interaction with the bone surface, the results reveal that the temperature of the points adjacent to the bone surface dramatically increases up to 85 °C. Meanwhile, the heat source is provided based on the Beer-Lambert law, and finally it demonstrates that the penetration depth exponentially reduces the intensity and causing considerable decrease in temperature. For the first time, the non-Fourier heat transfer equation was solved using the Laplace transform method for the tibia bone, and its results were compared with the numerical solution results using the Leap- Frog method. Knowing the temperature changes caused by laser inside the tissue is very crucial in Laser tissue welding, tissue ablation, photocoagulation and photo-thermal denaturation, angioplasty, treatment of granulation tissues, change and deformation of cartilage.

Efficiency of electrical welding of soft tissues during thyroid gland operations

Annotation. The purpose of the study was to study the results of using electro welding of tissues during operations on the thyroid gland in benign (nodular and multinodular goiter) and malignant (differentiated carcinoma) pathological conditions. Electric welding was ensured due to the formation of coagulum between the branches of the clamp during the action of short-duration pulses of radio frequency (440 kHz) current with a maximum power of 300 W when using a device manufactured in Ukraine by LLC “Swarmed” with the patented technology “Biowelding TM”. The results of surgical treatment of 183 patients who underwent hemi thyroidectomy (8.7%), thyroidectomy (61.2%), and thyroidectomy with dissection of the 6th collector of the neck (30%) for nodular goiter, multinodular goiter, and differentiated thyroid carcinoma, respectively, were analyzed. The use of electric welding made it possible to reduce skin incisions on the neck during surgical access (the average length of the incision was 3.77±0.02 cm). Unilateral temporary paresis of the larynx was recorded in 2 (1.1%) patients, temporary hypoparathyroidism in 3 (1.6%) patients. Bleeding, neck hematomas and wound seroma did not occur in the postoperative period. Electric welding provides reliable hemostasis, which allows you to avoid the use of other means for ligation of vessels (threads, metal clips). The average length of stay of patients in the hospital was 1.1±0.01 days.

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.

High-frequency equipment for live tissue welding (Review)

High-frequency equipment for live tissue welding (Review)

RESULTS OF INFLAMMATORY AND IMMUNOLOGICAL PARAMETERS OF THE ORAL CAVITY AFTER CYSTECTOMY WITH DIFFERENT METHODS OF CONNECTING THE EDGES OF THE OPERATED AREA.

The aim: To analyze the results of inflammatory and immunological parameters of the oral cavity after cystectomy with different methods of connecting the edges of the operated area. Materials and methods: The research was conducted in 87 patients who sought surgical treatment of odontogenic cysts of the jaws. Patients were divided into groups depending on the method of wound closure after surgery. We analyzed the results of laboratory tests (leukocytes, ESR, IL-1β, IL-6, TNF-α, IL-8, NO synthase, MMP-9). Results: The analysis of the effectiveness of using different methods of approximation of the oral mucosa wound on inflammatory and immunological pa¬rameters showed that when using welding of the edges of the operated area using the EKVZ-300 "Patonmed" apparatus, we get positive results of laboratory indicators of inflammatory markers faster (leukocyte counts are normal on day 30, ESR, IL-1β - on the 14th day, TNF-α - on the 7th day, IL-6, IL-8, NO synthase, MMP-9 - on the 30th day), that is, healing in such patients is faster than in patients with wound closure with classic suture material or laser. Conclusions: When comparing the methods of approximation of postoperative oral mucosa wounds by different methods, based on the results of these inflammatory and immunological parameters, the best results were obtained when using electric welding of tissues. Further research and use of the proposed method will facilitate and shorten the rehabilitation period of patients after surgery.

Experimental study of thermal damage to in vitro skin tissue welding by femtosecond laser

This study aims to investigate and evaluate the thermal damage changes during femtosecond laser welding in vitro skin tissue. Based on the orthogonal test, a grey-scale co-occurrence matrix was used to extract the textural characteristic values of the microscopic tissue and to find the correspondence between the peak temperature and the textural characteristic values of the in vitro skin tissue. The statistical analysis software Minitab was used to design an orthogonal test, with laser power, laser scanning speed, off-focus amount, and laser scanning times as independent variables and the degree of thermal damage of in vitro skin tissue as the dependent variable, to establish the association between the four influencing factors and the degree of thermal damage. The microstructure of the laser-welded in vitro skin tissue is close to normal tissue with little thermal damage and high tensile strength when the laser power is 14 W, the scanning speed is 50 mm/s, and the off-defocus amount is −1mm, and the laser scanning times are 75. Extreme difference analysis was used to identify significant parameters impacting heat damage in skin tissue, and the associated mechanisms were analyzed. This research can be utilized to better understand and improve the quality of ultrashort pulse laser welding to biological tissues.

COMPARISON OF THE EFFICIENCY OF THE CLOSURE OF DEFECTS OF DURA MATER WITH HIGH-FREQUENCY ELECTRIC WELDING TO TRADITIONAL SEWING CONNECTION

A comparison of the effectiveness of closure of dura mater defects in the surgical removal of tumors of the frontal sinuses with intracranial snvaiding by methods of high-frequency electric welding of tissues and traditional sutures. A comprehensive assessment of methods by a group of indicators for both direct surgery and rehabilitation period was used. Significant advantages of high-frequency bipolar electric welding in comparison with traditional seam connection are shown.Usage of biological welding contributes to a significant reduction of intra- and postoperative complications, shortening the operation time, reduced duration of postoperative treatment compared to traditional methods.

Dynamic Impedance Analysis of Intestinal Anastomosis during High-Frequency Electric Field Welding Process.

The success rate of the electrosurgical high-frequency electric field welding technique lies in reasonable control of the welding time. However, the final impedance value used to control the welding time varies due to differences in tissue size and the welding method during the welding process. This study aims to introduce a new reference indicator not limited by impedance size from dynamic impedance to achieve an adequate weld strength with minimal thermal damage, providing feedback on the tissue welding effect in medical power supplies. End-to-end anastomosis experiments were conducted with porcine small intestine tissue under seven levels of compression pressure. The dynamic impedance changes were analyzed, combined with compression pressure, temperature, moisture, and collagen during welding. The welding process was divided into three stages according to the dynamic impedance, with impedance decreasing in Period Ⅰ and impedance increasing in Period Ⅲ. Period Ⅲ was the key to high-strength connections due to water evaporation and collagen reorganization. The dynamic impedance ratio is defined as the final impedance divided by the minimum impedance, and successful welding would be predicted when detecting the dynamic impedance ratio over 4 (n = 70, p < 0.001). Dynamic impedance monitoring can be used as a macroscopic real-time prediction of the anastomosis effect.

Динаміка клінічних показників після цистектомії з використанням електрозварювання країв прооперованої ділянки у пацієнтів з одонтогенними кістами щелеп

Goal. To evaluate the effectiveness of the proposed method of cystectomy using electric welding on the basis of the obtained clinical and biochemical parameters. Materials and methods. Cystectomy was performed in 87 patients: 20 patients – 1 control group (classical surgical method), 28 patients – 2 control groups (cystectomy using laser technology) and 39 patients – the main group (cystectomy using electric welding). Results. The use of electric welding technology during cystectomy allowed to reduce and facilitate the postoperative period in patients of the main group up to 5 days in contrast to patients in other groups, in which symptoms of inflammation and pain were observed up to 14 days. Conclusions. The use of electric welding of tissues during cystectomy in the oral cavity allowed to achieve sterility of the operated area, reduce the intervention time, and due to the absence of foreign bodies in the wound to reduce and facilitate postoperative rehabilitation of patients. Key words: odontogenic cyst, cystectomy, electric welding of tissues, postoperative complications.

Effect of Applied Force on the Quality of Laser Skin Tissue Welding

Effect of Applied Force on the Quality of Laser Skin Tissue Welding