Tissue Incision Research Articles

FORESTIER DISEASE

Introduction We present the case of M.E., a 73 year old patient, who presented to his local medical services for progressive dysphagia. Follow-up cervical CT scan revealed ossification of the anterior longitudinal ligament, at C3 - C4, C4 - C5 and C5 - C6 levels, consistent with diffuse idiopathic skeletal hyperostosis (DISH), also known as Forestier disease. Material and Methods The patient was operated on by a multidisciplinary team (Neurosurgery and O.M.F. surgery). After a left sided vertical cervical incision and dissection of tissue, the spinal cervical levels were identified radiologically, followed by reduction of bony elevations at C3 - C4, C4 - C5 and C5 - C6 using a regular drill tip. Postoperatively the patient’s dysphagia was completely alleviated. Conclusion Although Forestier disease is usually identified incidentally, patients may present with decreased neck mobility, cervical pain and dysphagia. While the disease is similar to ankylosing spondylitis, it does not have a genetic component and it mainly affects the cervical and thoracic spines. Surgery may be necessary if dysphagia progresses.

Injectable alginate chitosan hydrogel as a promising bioengineered therapy for acute spinal cord injury

Dealing with spinal cord injuries presents problematic due to multiple secondary mechanisms. Beyond primary concerns like paralysis and disability, complications including urinary, gastrointestinal, cardiac, and respiratory disorders, along with substantial economic burdens may occur. Limited research focuses on modeling and treating contusion and compression injuries. Tissue engineering emerges as an innovative treatment, targeting lesion pathophysiology. This study was evaluated implanting injectable biomaterials into injury-induced cavity before glial scar formation, avoiding tissue incisions and minimizing further damage. The efficacy of injectable alginate/thiolated chitosan hydrogel was investigated for acute spinal cord injury induced by Vanický method in Wistar rats. Three days post-injury, hydrogel was administrated through microinjection after laminectomy. After 60 days, the hydrogel group demonstrated notable motor function enhancement compared to the control by the BBB locomotor test (P < 0.05). However, no statistically significant differences were observed in MRI assessment concerning lesion severity. Stereological and histopathological evaluations revealed a reduction in vacuole volume and the presence of axon profiles within the scaffold (P < 0.05), alongside reduced infiltration of inflammatory and Gitter cells in the hydrogel group, although the latter was not statistically significant compared to the control. Thiolated chitosan/ alginate hydrogel implantation may be regarded as a promising treatment to enhance motor function by restraining destructive processes post-acute spinal cord injury.

A Teleoperated Robotic System with Haptic Feedback for Soft Tissue Incision

A Teleoperated Robotic System with Haptic Feedback for Soft Tissue Incision

Comparison of the effects of Ho: YAG laser virtual Basket™ pulse modulation and Thulium fiber laser on kidney tissue - an ex vivo experimental study.

Through an ex vivo experimental study, we aimed to compare the effects of the Ho: YAG laser Virtual Basket (VB™) modulation and a Thulium fiber laser (TFL) on kidney tissue in different environments and using laser configurations. The 100W Ho: YAG (Cyber Ho, Quanta System, Italy) and 60W TFL (Fiber Dust, Quanta System, Italy) laser devices were used. The following laser settings were selected: power in the range of 10-60W, frequency of 20-40Hz, and energy of 0.5-1-1.5J. A medium pulse duration of 600 µsec was used for VB™, while short (spdTFL; 50 µsec) and long (lpdTFL; 15,000 µsec) were used for TFL. The tissue's incision depth (ID), vaporization area (VA), coagulation area (CA), total laser area (TLA = VA + CA), surface section (SS), and lateral effect (LE) were measured. In total, 108 experiments were conducted. No statistically significant difference in mean VA, TLA, ID, LE, or SS was observed between VB™, spdTFL, and lpdTFL in the low-power output group in saline (p > 0.05). However, the mean CA was statistically significantly higher for VB™ (p = 0.005). In saline and high-power output group, the mean VA, CA, TLA, LE, and ID were higher when using lpdTFL than other pulse durations (p = 0.001, p = 0.001, p = 0.001, p = 0.006, and p = 0.001, respectively). Similar to lpdTFL, VB™ may provide controlled dissection and incision as well as haemostasis. At different laser settings, the individual effects of laser properties (such as pulse length, energy and frequency) on tissue may be more significant.

When Antimicrobial Treatment and Surgical Prophylaxis Collide: A Stewardship Opportunity.

Background: In 2002, the Centers for Medicare and Medicaid Services (CMS) in collaboration with the Centers for Disease Control and Prevention (CDC) established the Surgical Infection Prevention (SIP) project for the purposes of developing and standardizing quality improvement measures known to reduce the rates of post-operative surgical site infections (SSIs). Four years later the Surgical Care Improvement Project (SCIP), an expansion of SIP, was published in governmental Specifications Manual for National Inpatient Quality Measures and provided several additional initiatives applicable to the perioperative period. Central to both projects are the assurance of the timeliness, selection, and duration of peri-operative surgical prophylactic antibiotics. In support of this objective, various medical associations, such as the American Society of Health-System Pharmacists (ASHP) and the Infectious Diseases Society of America (IDSA), have developed the Clinical Practice Guidelines for Antimicrobial Prophylaxis in Surgery. To ensure compliance with quality measures, hospitals are required to report data to the Physicians Quality Reporting System, which is then reviewed by CMS for reimbursement purposes and to measure hospital performance. To maintain optimal standards of care and satisfy all core measures, it is expected that patients undergoing most categories of surgical procedures receive prophylactic antibiotics. We recognized that patients already being administered antimicrobial therapy as treatment for the condition requiring the surgery not uncommonly also were prescribed unwarranted and redundant pre-operative antibiotics. Our study was meant to quantify such antibiotic redundancy, which only risks the development of antimicrobial resistance and adverse events, to bolster our and other hospitals antimicrobial stewardship programs. Methods: A retrospective analysis of computerized hospital records over a one-month period of time (November 2022) was conducted focusing on hospital admissions that involved surgical operative procedures. Only those patients who had received a pre-operative surgical prophylactic antibiotic were included in the analysis. Results: Of the 92 surgeries that fulfilled the inclusion criteria, 38 (41.3%) were performed on patients who were already receiving therapeutic antibiotics for more than 24 hours targeted to treat the infection for which they were undergoing surgery. These included laparoscopic cholecystectomy (24), appendectomy (12), wound debridement (12), and soft tissue incision and drainage procedures (9), comprising nearly 50% of each type of these operations performed during the study time period. Conclusion: These findings demonstrate a clear opportunity to strengthen both our, and presumably other, hospitals antimicrobial stewardship programs. Together with physician education, granting the pharmacy the ability to cancel unnecessary and redundant surgical prophylactic antibiotics would conceivably be of great benefit.

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.

Modified Valente Technique for Cauliflower Ear: Outcomes in Children at Two-Year Follow-Up

BackgroundCauliflower ear deformity, a common sequela of auricular trauma, presents an esthetic and reconstructive challenge. Existing surgical techniques have limitations, including complexity, donor site morbidity, and variable long-term outcomes.Materials and MethodsIn this case series, we present a novel and minimally invasive surgical approach for the correction of cauliflower ear deformity that adapts the Valente otoplasty technique; it combines cartilage debulking with helical rim release and Mustardé mattress stitches to restore ear contour and reduce the risk of recurrence. The procedural steps include bielliptic post-auricular skin and soft tissue incision, release of the cartilaginous spring, removal of excess fibrocartilaginous tissue, cartilage reshaping with suture to restore contour, and tissue redistribution to promote adherence of skin to the cartilage framework.ResultsOutcomes were evaluated in 7 patients (9 ears) with cauliflower ear deformity, assessing surgical duration, complications, patient satisfaction, and esthetic outcomes at two years after surgery. The mean surgical duration per patient was 52 ± 17 minutes, including 2 bilateral procedures. Follow-up at 24 months showed favorable esthetic outcome in all patients with sustained improvements in auricular contour and symmetry with neither loss of the shape nor recurrence of deformity. Patients reported high satisfaction and improved quality of life, with mean Glasgow Children Benefit Questionnaire scores of 99.3 ± 6.3.ConclusionsThis technique thus demonstrated lasting correction of cauliflower ear with favorable cosmetic outcomes, low risk of complications, and high patient satisfaction. Further investigations and longer-term follow-up are warranted to validate the technique's durability and expand its application to older and more diverse patient populations.Level of Evidence IVThis journal requires that authors assign a level of evidence to each article. For a full description of these evidence-based medicine ratings, please refer to the Table of contents or the online Instructions to Authors www.springer.com/00266.

IL-33/ST2 induces macrophage-dependent ROS production and TRPA1 activation that mediate pain-like responses by skin incision in mice.

Background: Insufficiently managed incisional (INC) pain severely affects patients' life quality and rehabilitation after a major operation. However, mechanisms underlying INC pain still remain poorly understood. Methods: A mouse model of INC pain was established by skin plus deep muscle incision. Biochemistry assay, in vivo reactive oxygen species (ROS) imaging, Ca2+ imaging combined with retrograde labelling, neuron tracing and nocifensive behavior test, etc. were utilized for mechanism investigation. Results: We found pro-nociceptive cytokine interleukin -33 (IL-33) ranked among top up-regulated cytokines in incised tissues of INC pain model mice. IL-33 was predominantly expressed in keratinocytes around the incisional area. Neutralization of IL-33 or its receptor suppression of tumorigenicity 2 protein (ST2) or genetic deletion of St2 gene (St2 -/-) remarkably ameliorated mechanical allodynia and improved gait impairments of model mice. IL-33 contributes to INC pain by recruiting macrophages, which subsequently release ROS in incised tissues via ST2-dependent mechanism. Transfer of excessive macrophages enhanced oxidative injury and reproduced mechanical allodynia in St2 -/- mice upon tissue incision. Overproduced ROS subsequently activated functionally up-regulated transient receptor potential ankyrin subtype-1 (TRPA1) channel innervating the incisional site to produce mechanical allodynia. Neither deleting St2 nor attenuating ROS affected wound healing of model mice. Conclusions: Our work uncovered a previously unrecognized contribution of IL-33/ST2 signaling in mediating mechanical allodynia and gait impairment of a mouse model of INC pain. Targeting IL-33/ST2 signaling could be a novel therapeutic approach for INC pain management.

Применение аллогенного диспергированного биоматериала для профилактики рубцовых осложнений при реплантации конечностей (экспериментальное исследование)

Aim: during research study, to identify the nature of cicatricial changes after limb replantation and to study the possibility of preventing fibrosis using an allogeneic biomaterial. Materials and Methods: the research was conducted on 48 male rats (24 each in the control and experimental groups). The operation consisted of a circular incision of soft tissues in the middle third thigh, followed by microvascular stitches of blood vessels, nerves, muscles and skin. In the experimental group, a dispersed allogeneic biomaterial (DAB), which is a sterile powder prepared from decellularized connective tissue, was applied to wound surfaces before stitching. The subjects were withdrawn from the study 7, 14, 30 and 90 days after surgery. Tissue samples from the surgical area were subjected to histology and immunohistochemistry: the expression of transforming growth factor (TGF-β1), tumor necrosis factor (TNF-α), antigen of the main histocompatibility complex (HLA-DR), myosatellitocyte marker (MyoD) was evaluated. Results: in the control group 90 days after surgery, fibroblastic sleeve was found around the vessels and nerves, as well as fibroblast foci between the stitched muscles, therefore, a typical picture of aseptic inflammation. This process was accompanied by high TGF-β1 and HLA-DR expression with low TNF-α expression. In the experimental group, DAB particles were biodegraded by macrophages and resorption. Fibrous membranes around the stitched vessels and nerves consisted of collagen fibers thinner than in the control group. Cicatricial changes were not detected at the sites of muscle stitching. At a later date (30 and 90 days), the vessels and nerves were surrounded by thin collagen fibers. TNF-α expression significantly exceeded that in the control group, while the TGF-β1 and HLA-DR expression remained at a low level. Given time (90 days), a defect cicatrization and a decrease in these cytokines expression were detected in both groups. Starting from the 14th day of the study, MyoD+myosatellitocytes were detected in the subjects of the experimental group, which indicated the muscle fiber regeneration. No MyoD+cells were detected in the subjects of the control group during the study. Conclusion: conducted study showed that aseptic inflammation occured during limb replantation, in the proliferative phase of which fibroblastic sleeve formed around stitched vessels and nerves, as well as fibroblast foci between fragments of stitched muscles, accompanied by high TGF-β1 and HLA-DR expression. The DAB allows to change the wound process course due to the macrophages activation of the proinflammatory phenotype, which is manifested by a significantly higher TNF-α expression, correlating with low TGF-β1 and HLA-DR expression. Under these conditions, vascular fibrosis is inhibited and damaged muscle fibers are regenerated. Thus, the DAB use in limb replantation helps to prevent vascular fibrosis and stimulate progenitor muscle cells. KEYWORDS: replantation, inflammation, fibrosis, allogeneic biomaterial, macrophages, TGF-β1, TNF-α, HLA-DR, myosatellitocytes, MyoD. FOR CITATION: Muslimov S.A., Ibragimov R.K., Lebedeva A.I. Dispersed allogeneic biomaterials for the prevention of cicatricial complications during limb replantation (research study). Russian Medical Inquiry. 2024;8(4):201–207 (in Russ.). DOI: 10.32364/2587- 6821-2024-8-4-3.

Histological evaluation of the surgical margins of oral soft tissue incisions using a dual-wavelength diode laser and an Er, Cr:YSGG laser; an ex vivo study.

This study compared a dual-wavelength diode laser and an Er, Cr:YSGG laser in oral soft tissue incisions to determine the most effective and safest laser system at the histopathological level. The (810 and 980 nm) dual-wavelength diode laser was used at 1.5 W and 2.5 W (CW) power settings, and the (2780 nm) Er, Cr:YSGG laser was used at 2.5 W and 3.5 W (PW) power settings. Both laser systems were used to incise the tissues of freshly dissected sheep tongue pieces to obtain the following histopathological criteria: epithelial tissue changes, connective tissue changes, and lateral thermal damage extent by optical microscopy. The epithelial and connective tissue damage scores were significantly higher in the dual-wavelength diode laser groups than in the Er, Cr:YSGG laser groups (P<0.001), and there was a significant difference between some groups. The extent of lateral thermal damage was also significantly higher in the diode laser groups than in the Er, Cr: YSGG laser groups (P<0.001), and there was a significant difference between groups. Group 2 (2.5 W) of the diode laser was the highest for all three criteria, while group 3 (2.5 W) of the Er, Cr:YSGG laser was the lowest. The Er, Cr:YSGG laser with an output power of 2.5 W is, histologically, the most effective and safest laser for oral soft tissue incision. The dual-wavelength diode laser causes more damage than the Er, Cr:YSGG laser, but it can be used with a low output power and 1 mm safety distance in excisional biopsy.

Experimental study on the mechanical properties and thermal damage of laser welding the ruptured flexor digitorum longus tendons.

To investigate the influence of laser parameters on the performance of tendon tissue, experiments were conducted and the process of laser-assisted tendon welding was studied. Several conclusions were drawn by analyzing the effects of laser parameters on the tensile strength, microstructure, and collagen content of tendon tissue incisions. The optimal parameters for laser welding tendon tissue were found to be a laser power of 5 W, a scanning speed of 150 mm/s, and a defocus amount of 0 mm, resulting in a laser energy density of 32.164 J/cm2 . At these parameters, the percentage of inactivated cells due to thermal damage was only 23.78%, and the tensile strength of the tendon tissue incisions reached 0.61 MPa. Additionally, the collagen content around the incision was measured to be 33.679%, composed of type I and type III collagens, with the latter accounting for 50.714% of the total collagen content.

Thermographic Changes During Soft Tissue Incisions with Diode Infrared Lasers

Thermographic Changes During Soft Tissue Incisions with Diode Infrared Lasers

Tissue Ablation with Multi‐Millimeter Depth and Cellular‐Scale Collateral Damage by a Femtosecond Mid‐Infrared Laser Tuned to the Amide‐I Vibration

AbstractLaser ablation of bio‐tissues is the key technology of future surgeries, owing to the merits of submicron accuracy, non‐contact operation, and precision control assisted by automation and computer intelligence. Excellent efficiency, minimal collateral damage, biological safety, and tissue selectivity are the ideal parameters for delicate surgical applications. Here, by exploring the mid‐infrared (MIR) resonant ablation and the femtosecond cold processing, tissue ablation with multi‐millimeter depth and cellular collateral damage, enabled by a tabletop femtosecond MIR optical parametric amplifier operating at the amide‐I resonant wavelength of 6.1 µm, is demonstrated. Remarkably, the collateral damage is observed to be 15, &lt;4, and &lt;1 µm in the porcine cornea, sclera, and articular cartilage, respectively, with multi‐millimeter incision depth. In addition, preliminary proof‐of‐concept experiments of tissue‐selective ablation, microchannels on cartilage for drug delivery, laser glaucoma, keratotomy, neurologic tissue incision, dentin deep crater formation, and hypertrophic scarring ablation are demonstrated, which pave the way for high‐precision surgical applications with a tabletop solution.

Analysis of the Temperature Elevation of the Dual-Wavelength Diode Laser and the Er, Cr: YSGG Laser in Oral Soft Tissue Incisions.

Introduction: Lasers are one of the most advantageous tools that have been used in a variety of medical fields. Soft tissue management is an important part of oral and maxillofacial surgery. There are different surgical procedures for management; one of them is laser surgery. The purpose of this study was to compare the dual-wavelength diode laser and the Er, Cr: YSGG laser to choose the most effective laser for a soft tissue incision in oral and maxillofacial surgery regarding temperature elevation. Methods: A dual-wavelength diode laser (810 and 980 nm) with 1.5 W and 2.5 W power outputs and an Er, Cr: YSGG (2780 nm) with 2.5 W and 3.5 W power outputs were used to make 50 incisions in six freshly dissected sheep tongues. The temperature means were measured at initial, maximum temperatures, as well as the temperature rise (difference between initial and maximum), and all were compared between the groups of soft tissue. Results: The lowest mean temperature rise was observed with a 2.5 W Er, Cr: YSGG laser, and the highest mean temperature rise was observed with a 2.5 W diode laser, and all samples from the two lasers showed a statistically significant difference (P<0.05) in the temperature rise except the 1.5 W diode, which is higher but not statistically significantly different from the 3.5 W Er, Cr: YSGG laser (P=0.100). Conclusion: The power output of 2.5 W of an Er, Cr: YSGG laser produced low levels of temperature rise compared to a diode laser and produced surgical incisions with a lower probability of heat damage to surrounding tissues.

Research on evolution process of full-layer incision of skin tissue under different laser incidences.

Considering difficulties of achieving vertical incidence of beam in different positions of skin, it is significant to study potential effects of incidence angles of laser on incisions. Surgical platform with a 1064 nm continuous fiber laser was established. Incident angle was adopted and real-time temperature fluctuations in laser operating area could be monitored. The rats were treated with laser at day 0 and day 3 after incision modeling, and H&E, Masson, Sirius Red, and Immuno-histochemical staining and enzyme-linked immunosorbent assay were adopted at day 3, 7, 14 to analyze the performance of healing. Laser with energy density of 67.54 J/mm2 can effectively accelerate wound healing in vivo, in which a laser with incident angle around 60° can effectively avoid scar hyperplasia. Therefore, the use of low energy laser with a small deflection angle has a good clinical application prospect in promoting wound healing.

Preclinical Investigation of Ab Interno Goniotomy Using Three Different Techniques.

To evaluate incisional or excisional tissue-level effects of ab interno goniotomy techniques on human trabecular meshwork (TM). The TM from human cadaveric corneal rim tissue was treated using three devices: (1) Kahook Dual Blade (KDB) GLIDE, (2) iAccess, and (3) SION. Two human corneal rims were used for each of the iAccess and SION devices and one with the KDB GLIDE, with 360 degrees of TM treated in each case. Sections were then prepared for analysis and comparison between devices. Tissue samples underwent standard histologic processing with H&E stain, followed by comparative analyses. Areas treated with the KDB GLIDE device resulted in nearly complete excision of TM overlying the canal of Schlemm without injury to surrounding tissues. The iAccess device can be used as a focal trephine to create holes or dragged for TM disruption. When used to create holes, iAccess punched through the full thickness of the TM and also disrupted the anterior scleral tissue. It caused some incisional openings through the TM but with significant leaflets remaining and minimal true "hole-punch" effect. When the device tip was dragged, iAccess incised the TM and left debris behind with little, if any, excision of tissue. SION led to both incision and excision of TM with incision predominating over excision. The various methods evaluated to perform ab interno goniotomy resulted in varying degrees of TM incision or excision. Only the KDB GLIDE device resulted in reliable excision of TM, while the other devices produced incision or minimal excision of tissue with residual leaflets and debris. Use of iAccess resulted in focal disruption of the anterior scleral wall. Because incisional approaches that leave longer residual leaflets may be more prone to fibrosis and closure compared to excisional treatments, clinical correlation will be necessary to better understand the significance of these findings with respect to relative effectiveness of intraocular pressure lowering in eyes with glaucoma.

Histological evaluation of mouse tongue incisions after Er:YAG laser surgery with different pulse energies versus after conventional scalpel surgery.

To identify the surgical instrument that allows for optimal healing of tongue incisions. An Er:YAG laser was compared with different pulse energies to a conventional scalpel for the incision of mouse tongue tissues. Mice were sacrificed through cervical dislocation at 24, 48, and 72 h postoperatively, followed by extraction of their tongues for incision experiments. The healing of the incisions and expression of inflammation- and pain-related factors in the tongues were compared between the surgical procedure groups. In laser-treated mice, tongue incisions healed the fastest when the laser output energy was 60 MJ per pulse. Macrophage chemotaxis toward the incisional area was triggered on the first postoperative day for the 60-MJ group, while the time for macrophage chemotaxis to the surgical area was later in the 80-MJ group. Tumor necrosis factor-alpha expression increased and then decreased in the 80-MJ group; however, it gradually decreased in the 60-MJ and conventional scalpel groups. Prostaglandin E2 expression increased and then decreased in the 80-MJ and conventional scalpel groups but gradually decreased in the 60-MJ group. The expression of transforming growth factor beta 1 gradually decreased in the 60-MJ and 80-MJ groups but gradually increased in the conventional scalpel group. Compared with surgical procedures using conventional scalpels, those using an Er:YAG laser with appropriate pulse energies can inhibit inflammation in the incisional area and promote incision healing. The use of an Er:YAG laser with appropriate pulse energies can alleviate intraoperative and postoperative pain in the incisional area.

Effect of longitudinal-bending elliptical ultrasonic vibration assistance on electrosurgical cutting and hemostasis

Electrosurgical devices are widely used for tissue cutting and hemostasis in minimally invasive surgery (MIS) for their high precision and low trauma. However, tissue adhesion and the resulting thermal injury can cause infection and impede the wound-healing process. This paper proposes a longitudinal-bending elliptical ultrasonic vibration-assisted (EUV-A) electrosurgical cutting system that incorporates an ultrasonic vibration in the direction of the cut by introducing an elliptical motion of the surgical tip. Compared with a solely longitudinal ultrasonic vibration-assisted (UV-A) electrosurgical device, the EUV-A electrode contacts the tissue intermittently, thus allowing for a cooler cut and preventing tissue accumulation. The experimental results reveal that the EUV-A electrode demonstrates better performance than the UV-A electrode for both anti-adhesion and thermal injury through in vitro experiments in porcine samples. The tissue removal mechanism of EUV-A electrosurgical cutting is modeled to investigate its anti-adhesion effect. In addition, lower adhesion, lower temperature, and faster cutting are demonstrated through in vivo experiments in rabbit samples. Results show that the EUV-A electrode causes lower thermal injury, indicative of faster postoperative healing. Finally, efficacy of the hemostatic effect of the EUV-A electrode is demonstrated in vivo for vessels up to 3.5 mm (equivalent to that of electrocautery). The study reveals that the EUV-A electrosurgical cutting system can achieve safe tissue incision and hemostasis.

Experimental study of the effect of temperature on collagen conformational changes in skin tissue welded by femtosecond laser

In this study, in vitro skin tissues were welded using various laser settings at four temperature ranges, 30–40 °C, 40–60 °C, 60–80 °C, and > 80 °C., Raman spectra between 500 and 2000 cm−1 were examined in order to examine the relationship between the changes of collagen and the mechanical properties of skin tissue bonding and the degree of thermal damage of tissue. How collagen in skin tissues changed into disordered and less stable structures due to the thermal damage, and how the structure of protein and amino acid-related bands changed with increasing temperature were analyzed. Analysis of the deconvolution of the amide I band (1580–1720 cm−1) and the secondary structure of collagen showed that the secondary structure of collagen changed from α-like helix-dominated to β-aggregate-dominated structures due to the thermal damage. As the temperature increased, the number of protein molecule chain dissociation and reconnection within the skin tissue increased, which contributed to the improvement of the tensile strength of the skin after welding. However, when the temperature was too high, the collagen structure presented an extremely unstable state, and the degree of protein denaturation increased, causing serious thermal damage. When the skin tissue was welded using the femtosecond laser process parameters of laser power of 18 W, scanning speed of 50 mm/s, and scanning 50 times, the tensile strength of the in vitro skin tissue incision was greater and the degree of protein denaturation was less. The degree of thermal damage characterized by the degree of protein denaturation was consistent with that characterized by the microstructure texture characteristics parameters of the skin tissue.

Control of drug release kinetics from hot-melt extruded drug-loaded polycaprolactone matrices.

Sustained local delivery of meloxicam by polymeric structures is desirable for preventing subacute inflammation and biofilm formation following tissue incision or injury. Our previous study demonstrated that meloxicam release from hot-melt extruded (HME) poly(ε-caprolactone) (PCL) matrices could be controlled by adjusting the drug content. Increasing drug content accelerated the drug release as the initial drug release generated a pore network to facilitate subsequent drug dissolution and diffusion. In this study, high-resolution micro-computed tomography (HR μCT) and artificial intelligence (AI) image analysis were used to visualize the microstructure of matrices and simulate the drug release process. The image analysis indicated that meloxicam release from the PCL matrix was primarily driven by diffusion but limited by the amount of infiltrating fluid when drug content was low (i.e., the connectivity of the drug/pore network was poor). Since the drug content is not easy to change when a product has a fixed dose and dimension/geometry, we sought an alternative approach to control the meloxicam release from the PCL matrices. Here, magnesium hydroxide (Mg(OH)2) was employed as a solid porogen in the drug-PCL matrix so that Mg(OH)2 dissolved with time in the aqueous environment creating additional pore networks to facilitate local dissolution and diffusion of meloxicam. PCL matrices were produced with a fixed 30wt% meloxicam loading and variable Mg(OH)2 loadings from 20wt% to 50wt%. The meloxicam release increased in proportion to the Mg(OH)2 content, resulting in almost complete drug release in 14 d from the matrix with 50wt%Mg(OH)2. The porogen addition is a simple strategy to tune drug release kinetics, applicable to other drug-eluting matrices with similar constraints.