Tissue Tension Research Articles

Comparison of Anterior Shoulder Pain and Internal Rotation Dysfunction after Anatomic and Reverse Shoulder Arthroplasty for Osteoarthritis.

There is controversy regarding whether reverse shoulder arthroplasty and anatomic shoulder arthroplasty lead to equivalent outcomes in the setting of glenohumeral osteoarthritis. RSA changes the shoulder's anatomy and biomechanics, altering soft tissue tension and arm length. The effects of these changes to the anatomy are incompletely understood and may lead to anterior shoulder pain and dysfunction. In addition, decreased internal rotation is a known limitation of RSA that is less frequently seen in anatomic total shoulder arthroplasty (aTSA). Differences in anterior shoulder pain and internal rotation dysfunction may not be apparent on standardized instruments of outcomes assessment. This study aims to develop a novel anterior shoulder pain and dysfunction survey (ASPDS) to classify anterior shoulder dysfunction and use an existing questionnaire, the functional internal rotation (FIR) score, to quantify internal rotation (IR) deficiency following RSA compared to aTSA when performed for osteoarthritis. A retrospective review of a single-institution database was conducted of patients two years postoperative from aTSA or RSA for glenohumeral osteoarthritis. Exclusion criteria included shoulder arthroplasty for indication other than osteoarthritis, subscapularis not repaired, or signs of rotator cuff tearing preoperatively. Walch glenoid morphology was classified based on CT scan or X-ray. A novel 7-question ASPDS survey was developed to target actions that require anterior deltoid function. The previously published 10-question FIR score was used to assess actions that necessitate IR function. Outcomes included scores for the ASPDS, FIR score, American Shoulder and Elbow Surgeons score (ASES), visual analogue pain scale (VAS), and Single Assessment Numeric Evaluation (SANE). Internal reliability of the questionnaires was assessed using Cronbach's alpha. Twenty-six patients were included in each aTSA and RSA group per the a priori power analysis. Demographic factors were not significantly different between groups (p>0.05). Mean ASPDS scores were lower in the RSA group (29.1 ± 5.1) compared to the aTSA group (32.7 ± 4.5) (p=0.001). Mean FIR score was also worse in the RSA group (43.1 ± 6.5) compared to the aTSA group (46.8 ± 7.3) (p=0.004). No difference was observed between RSA and aTSA groups for ASES, SANE, and VAS scores (p>0.05). Cronbach's alpha was 0.889 for the ASPDS questionnaire and 0.935 for the FIR score. The ASPDS is a reliable questionnaire for characterizing anterior shoulder pain and dysfunction following shoulder arthroplasty. Initial findings suggest that anterior shoulder pain and dysfunction and decreased internal rotation are more common in RSA compared to aTSA when performed for osteoarthritis, with differences observed at two years postoperatively. These differences in outcomes were not captured by traditional shoulder outcomes questionnaires.

Tongue Prick Bionic Angularly Adjustable Microneedles for Enhanced Scarless Wound Healing

AbstractHigh‐tension site wounds are frequently accompanied by challenges associated with hypertrophic scarring. The key to achieving scar‐free healing is the creation of a mechanical environment conducive to scar‐free skin regeneration. Herein, simple rolling punctures are utilized on angle transform molds to develop cat tongue prick bionic angle‐adjustable microneedles (TPMNs) to maintain a firm grip on the periwound skin, thereby reducing tissue tension. The integration of TPMNs with triboelectric nanogenerators (TENGs) enables excellent conductive and triboelectric properties. The system can provide a stable spatial electric field around the wound to promote cell migration. As the microfluid reaches the TPMNs, the self‐driving force is enhanced by a unique angle design to control the microfluid flow rate. Sufficient evidence has shown that TPMNs expedite wound contraction and skin tissue regeneration while concurrently reducing scar formation in mouse trauma model experiments. The innovative TPMNs‐TENGs synergistically provides a highly functional platform for wound tension relief, which is suitable for scar treatment in this study and potentially extends to the construction and regulation of smart wearable devices.

Microstring-engineered tension tissues: a novel platform for replicating tissue mechanics and advancing mechanobiology.

Replicating the mechanical tension of natural tissues is essential for maintaining organ function and stability, posing a central challenge in tissue engineering and regenerative medicine. Existing methods for constructing tension tissues often encounter limitations in flexibility, scalability, or cost-effectiveness. This study introduces a novel approach to fabricating soft microstring chips using a sacrificial template method, which is easy to operate, offers controlled preparation, and is cost-effective. Through experimental testing and finite element simulations, we validated and characterized the relationship between microstring deformation, tissue width, and the reaction force exerted by the microstrings, enabling precise measurement of tissue contraction force. We successfully constructed microstring-engineered tension tissues (METTs) and demonstrated that they exhibit a significant mechanical response to profibrotic factors. Additionally, we conceptually demonstrated the application of microstring chips in constructing METTs with asymmetric, biomimetic constraints. The results indicate effective construction and regulation of METTs, providing a robust platform for mechanobiology and biomedical research.

Bifurcating Method for Subcutaneous Indwelling of Nonabsorbable Threads.

Subcutaneous indwelling of nonabsorbable threads for tissue fixation and tension reduction is often used in plastic surgery and is applied in breast reduction surgery, umbilicoplasty, and in frontalis muscle lifting for congenital ptosis. However, in a few cases, exposure of the indwelling thread necessitates its removal. Exposure of the indwelling threads mostly occurs due to exposure of the knots. Therefore, we require a novel method to ensure that the knot of the indwelling thread remains unexposed. Hence, we created a stab incision to place the indwelling nonabsorbable threads ligated with moderate tensile force. Furthermore, we attached needles to each end of the ligated thread. The needles penetrated from the stab incision through the depths to separate sites farther away from each other. Finally, we towed and cut the exposed thread from the skin. Thus, the knots on the indwelling thread may be positioned deeper, reducing the risk of exposure to the indwelling thread. Furthermore, the risk of overcorrection is reduced as each end of the indwelling threads penetrates a different site. In addition, this method leaves certain length of the end of the knot under the skin, which improves the visibility of the indwelling thread during revision surgery, facilitates access, and reduces the operative time. Application of this method in subcutaneous indwelling of nonabsorbable threads may reduce complications and time required for revision surgery.

ВЛИЯНИЕ СУЛЬФАТИАЗОЛА СЕРЕБРА НА ЗАЖИВЛЕНИЕ КОЖНЫХ РАН, ОБРАЗУЮЩИХСЯ ПРИ ПРОРЕЗЫВАНИИ СПИЦАМИ АППАРАТОВ НАРУЖНОЙ ФИКСАЦИИ

The study of the healing mechanisms of skin wounds resulting from damage to the skin by transosseous needles of external fixation devices in the treatment of osteoarticular pathology with the aim of further targeted correction of these processes is one of the urgent tasks of modern traumatology and orthopedics. The effect of silver sulfathiazole, recommended for the prevention of infectious complications, on the healing of this type of wound has not been studied previously. The aim of the study was to investigate the effect of silver sulfathiazole on the healing of skin wounds formed during the cutting of external fixation devices by pins. The experimental study was performed on 35 sexually mature male Wistar rats. Modeling of a skin wound formed during the cutting of external fixation devices by pins was carried out in sterile operating room conditions, under drug anesthesia of animals that underwent transosseous osteosynthesis of the femur using an original design of the external fixation device. By tractional movement of the proximal pin with a dosed stretching of the supports at a rate of 1 mm in 4 steps, tension and cutting of the skin were carried out for 10 days (the distraction period), then the device was in a static position for 15 days (the period of fixation of the limb in the device), after which the device was dismantled and observation was carried out for another 30 days. The animals were divided into 2 groups. In the control group, the simulated wound healed under natural healing conditions; in the experimental group, silver sulfathiazole applications were performed twice daily during the distraction period. Skin wounds were examined using light microscopy and morphometry after 10 days of distraction, 15 days of fixation, and 30 days after the apparatus was removed. The thickness of the epidermis, dermis, and the numerical density of the sebaceous glands and hair follicles were measured on digital images of histological preparations stained with hematoxylin and eosin. The volume density of elastic fibers was determined on preparations stained with orcein according to Tenzer-Unn. The obtained quantitative data were subjected to statistical analysis. The study showed that the formation of a skin wound with transosseous pins is accompanied by tissue tension. Healing of this type of wound occurs with a delay in epithelialization and an increase in the duration of the inflammatory phase. This affects the mechanisms of extracellular matrix synthesis and leads to the formation of scar tissue in the area of damage. The use of silver sulfathiazole applications promotes accelerated wound closure by epithelium, a reduction in the period of inflammation, normalization of elastin synthesis, and a decrease in cicatricial changes in the skin regenerate.

The Fat-Dachsous planar polarity pathway competes with hinge contraction to orient polarized cell behaviors during Drosophila wing morphogenesis.

During tissue morphogenesis, an interplay of biochemical pathways and mechanical cues regulates polarized cell behaviors, the balance of which leads to tissues reaching their correct shape and size.1,2,3,4 A well-studied example of a biochemical regulator is the highly conserved Fat-Dachsous (Ft-Ds) pathway that coordinates planar polarized cell behaviors and growth in epithelial tissues.5,6 For instance, in the Drosophila larval wing disc, the Ft-Ds pathway acts via the atypical myosin Dachs to control tissue shape by promoting the orientation of cell divisions primarily in a proximodistal (PD) direction.7,8 Here, we investigate interactions between Ft-Ds planar polarity and mechanical forces in the developing Drosophila pupal wing. We show that in the early stages of pupal wing development (16-18h after puparium formation), anteroposterior (AP)-oriented cell divisions and T1 transitions are controlled by the Ft-Ds pathway acting via Dachs. Shortly thereafter, PD-oriented tissue tension is induced across the wing blade by the process of hinge contraction. This opposes the control of Dachs over polarized cell behaviors in a tug-of-war fashion, resulting in more PD-oriented cell divisions and T1s. Furthermore, increased PD tissue tension stabilizes Ft along PD-oriented junctions, suggesting that biomechanical feedback on the Ft-Ds pathway resists the effects of hinge contraction on cell shape. We also show that loss of Dachs results in increased myosin-II stability at cell junctions, revealing compensatory interactions between these two myosins. Overall, we propose that Ft-Ds pathway function constitutes a mechanism whereby tissues are buffered against mechanical perturbations.

Role of Daruharidra Rasakriya Lepa in the management of Dushta Vrana w.s.r. to Chronic Non-Healing Ulcer : A Clinical Study

Background: Vrana is an interruption of continuity of body tissue or part by physical, microbial, chemical or immunological causes, typically associated with loss of function. Vrana can be correlated with wounds and ulcers. Normally, Vranas are healed by itself if kept clean. Wound factors delay wound healing. The presence of infection, insufficient blood supply, tissue tension, radiation, malnutrition, diabetes, consumption of steroids etc. are the important factors which delay the wound healing process. Dushta Vrana is one of the Vranas which needs time for its healing. Acharya Sushruta mentioned Rasakriya under Shasti Upakramas for management of Vrana. Any drug formulation should possess two qualities for proper wound healing i.e., Vrana Shodhana (Making free from undesirable wound factors) and Vrana Ropana (Closure of the wound). Many formulations are in use for centuries. One of them is Daruharidrarasakriya. The objective of the present study is to evaluate the effect of Daruharidraraskriya on the basis of relief in signs and symptoms of Dushta Vrana. Materials and Methods: In this study, Lepa of Daruharidrarasakriya was applied on affected part of 25 patients selected from Shalya OPD, GAMC&H, Akhnoor, for the management of Vrana. Results: The results observed based on the relief obtained on the subjective and objective parameters taken for consideration for this study viz. Pain, Size of ulcer, Discharge, Base (granulation tissue) and were found significant on all the above parameters. Conclusion: It showed that Daruharidraraskriya significantly helped in reduction of the signs and symptoms of the Dushta Vrana, enhancing wound healing process and reducing the morbidity of the patients.

Development: Turing mechanics.

Embryo axis formation begins with the localized expression of biochemical signals, which organize cell movements and determine cell fate. A quail study finds that tissue contraction and resulting long-range changes in tissue tension restrict the area where these biochemical signals are expressed.

FISIOTERAPIA APLICADA NO PROCESSO CICATRICIAL DE CESÁREAS: REVISÃO DA LITERATURA

Physiotherapy plays an important role in the recovery process after a cesarean sec tion, where it works by promoting an adequate healing process, reducing all discomfort, aiming at elasticity, preventing a hypertrophic scar and mainly, improving the physical function of patients. It is important that physiotherapy is personalized according to individual needs and carried out as soon as possible, as early initiation of physiotherapy and adherence to the guidelines provided are essential for a successful recovery after a cesarean section. In this process, we can use massage and tissue mobilization techniques, where the application of gentle mas sages and mobilization techniques will help reduce tension in scar tissues, promoting blood circulation and helping to break down adhesions that may form during the process. of healing. In conjunction with manual therapies, we can use physical therapeutic resources, where the physiotherapist will work, for example, with low-intensity laser therapy, which can accelerate the healing process, reduce inflammation and alleviate discomfort in the area. of the incision. Other physical modalities, such as therapeutic ultrasound and electrotherapy, can also be applied to promote healing and reduce pain.

Loss of Cdc42 causes abnormal optic cup morphogenesis and microphthalmia in mouse.

Congenital ocular malformations originate from defective morphogenesis during early eye development and cause 25% of childhood blindness. Formation of the eye is a multi-step, dynamic process; it involves evagination of the optic vesicle, followed by distal and ventral invagination, leading to the formation of a two-layered optic cup with a transient optic fissure. These tissue folding events require extensive changes in cell shape and tissue growth mediated by cytoskeleton mechanics and intercellular adhesion. We hypothesized that the Rho GTPase Cdc42 may be an essential, convergent effector downstream of key regulatory factors required for ocular morphogenesis. CDC42 controls actin remodeling, apicobasal polarity, and junction assembly. Here we identify a novel essential function for Cdc42 during eye morphogenesis in mouse; in Cdc42 mutant eyes expansion of the ventral optic cup is arrested, resulting in microphthalmia and a wide coloboma. Our analyses show that Cdc42 is required for expression of the polarity effector proteins PRKCZ and PARD6, intercellular junction protein tight junction protein 1, β-catenin, actin cytoskeleton F-actin, and contractile protein phospho myosin light chain 2. Expression of RPE fate determinants OTX2 and MITF, and formation of the RPE layer are severely affected in the temporal domain of the proximal optic cup. EdU incorporation is significantly downregulated. In addition, mitotic retinal progenitor cells mislocalize deeper, basal regions, likely contributing to decreased proliferation. We propose that morphogenesis of the ventral optic cup requires Cdc42 function for coordinated optic cup expansion and establishment of subretinal space, tissue tension, and differentiation of the ventral RPE layer.

Intra-rater and inter-rater reliability of a handheld myotonometer measuring myofascial stiffness of lower lumbar myofascial tissue in healthy adults.

Biomechanical muscle properties, such as stiffness, can be valuable indicators of tissue health and show promise as a diagnostic and treatment measure for chronic low back pain (CLBP). The development of accessible assessment technologies, such as the MyotonPRO portable device, allows for the convenient quantification of muscle tone and stiffness changes. The aim of this study is to assess the reliability of lumbar erector spinae muscle stiffness with the MyotonPRO in healthy adults and to compare stiffness changes between prone and sitting position. Thirty asymptomatic participants (N = 15 women and N = 15 men) aged between 18 and 65 years were recruited to participate in this study. Two examiners tested muscle stiffness at the palpable muscle belly, one finger away from the spinous process at the level of the L4 vertebra, first from the left and then from the right side, both in prone position and after in sitting position. For inter-rater reliability, all participants were tested by two examiners on the same day, and intra-rater reliability was calculated using the same examiner's assessment results with an exact 24-h interval. Intraclass correlation coefficients (ICC), standard error measures (SEM) and minimum detectable change (MDC) with a 95% confidence interval were calculated to assess intra-rater and inter-rater reliability. Statistical analysis revealed good intra-rater reliability with an ICC of 0.88 (95% CI [0.76-0.94]) for the stiffness of the left erector spinae and excellent intra-rater reliability with an ICC of 0.91 (95% CI [0.82-0.95]) for the right erector spinae, both in the prone position. Intra-rater reliability in the sitting position was excellent to very good with an ICC of 0.91 (95% CI [0.82-0.96]) for the left side and an ICC of 0.89 (95% CI [0.78-0.95]) for the right side. The results for the left-sided prone position showed good inter-rater reliability with an ICC of 0.87 (95% CI [0.73-0.94]). The prone position on the right side also showed good inter-rater reliability with an ICC of 0.84 (95% CI [0.68-0.92]). The inter-rater reliability for the left and right side in the sitting position was excellent with an ICC of 0.96 (95% CI [0.92-0.98]) for the left side and an ICC of 0.95 (95% CI [0.90-0.97]) for the right side. This study demonstrated high reliability in measuring lumbar erector spinae muscle stiffness with the MyotonPRO in healthy adults and the ability of the device to detect even small changes in erector spinae muscle stiffness, testing both the right and left sides and measuring in both prone and sitting positions. The use of the sitting position to assess lumbar tissue tension in individuals may serve as a valuable substitute for the prone position, particularly for patients who experience discomfort in the prone position, and could have additional practical significance in clinical settings.

Loss of Cdc42 causes abnormal optic cup morphogenesis and microphthalmia in mouse.

Congenital ocular malformations originate from defective morphogenesis during early eye development and cause 25% of childhood blindness. Formation of the eye is a multi-step, dynamic process; it involves evagination of the optic vesicle, followed by distal and ventral invagination, leading to the formation of a two-layered optic cup with a transient optic fissure. These tissue folding events require extensive changes in cell shape and tissue growth mediated by cytoskeleton mechanics and intercellular adhesion. We hypothesized that the Rho GTPase Cdc42 may be an essential, convergent effector downstream of key regulatory factors required for ocular morphogenesis. CDC42 controls actin remodeling, apicobasal polarity, and junction assembly. Here we identify a novel essential function for Cdc42 during eye morphogenesis in mouse; in Cdc42 mutant eyes expansion of the ventral optic cup is arrested, resulting in microphthalmia and a wide coloboma. Our analyses show that Cdc42 is required for expression of the polarity effector proteins PRKCZ and PARD6, intercellular junction protein tight junction protein 1, β-catenin, actin cytoskeleton F-actin, and contractile protein phospho myosin light chain 2. Expression of RPE fate determinants OTX2 and MITF, and formation of the RPE layer are severely affected in the temporal domain of the proximal optic cup. EdU incorporation is significantly downregulated. In addition, mitotic retinal progenitor cells mis-localized deeper, basal regions, likely contributing to decreased proliferation. We propose that morphogenesis of the ventral optic cup requires Cdc42 function for coordinated optic cup expansion and establishment of subretinal space, tissue tension, and differentiation of the ventral RPE layer.

Radiological and biomechanical evaluation of the ulnar nerve after the percutaneous application of the medial K-wire in the extended position on supracondylar humerus fractures: Does the postoperative long arm splint position matter?

Our study aimed to evaluate and compare the changes in ulnar nerve tension and strain at different elbow positions radiologically and mechanically before and after applying the medial K-wire on the supracondylar humerus fracture cadaver model. We used ten fresh frozen cadaver upper extremity specimens to measure strain and tension on the ulnar nerve in 3 different elbow positions: elbow full extension, elbow flexion-forearm supination, and elbow flexion-forearm pronation. We employed Shear wave elastography (Siemens Acuson S3000 USG, 9L4 linear probe) and a microstrain gauge (Microstrain, Inc., Burlington) to obtain our measurements. Minimum, maximum and mean stress and strain values on the nerve and its surroundings were measured and compared statistically. The mean values of elbows with full extension are statistically lower than those in elbows with 90° flexion-forearm supination and those with 90° flexion-forearm pronation positions. Statistical evaluations were performed between all of the groups. Elbow 90° flexion-forearm pronation, both minimum and maximum and mean values were statistically higher in the group, including the specimens with Kirschner applied. The mean values in the elbow full extension and elbow 90° flexion-forearm supination positions were statistically similar in the specimens with and without the K-wire applied. Despite the numerous techniques described in the literature, there is no absolute technical method to prevent ulnar nerve damage. K-wire application to the medial epicondyle with the elbow in a slightly extended position is a technique that can be applied to reduce the risk of ulnar nerve paralysis. However, it has been reported that ulnar nerve damage can be observed in cases where a splint is placed in the 90° flexion position. We hypothesize that the position of the elbow joint in the postoperative period may contribute to ulnar nerve paralysis due to soft tissue tension and strain and as a result of changing the balance of the surrounding tissues. Our findings suggest that the long arm splint applied in elbow 90° flexion and forearm pronation position should not be preferred in the postoperative period. The maximum strain values obtained in the elbow full extension were lower, suggesting that it would be appropriate to stabilize the elbow in the extension position as much as possible postoperatively. Level of evidence: Level V.

Mesodermal fibronectin controls cell shape, polarity, and mechanotransduction in the second heart field during cardiac outflow tract development.

Failure in the elongation of the cardiac outflow tract (OFT) results in congenital heart disease due to the misalignment of the great arteries with the left and right ventricles. The OFT lengthens via the accretion of progenitors from the second heart field (SHF). SHF cells are exquisitely regionalized and organized into an epithelial-like layer, forming the dorsal pericardial wall (DPW). Tissue tension, cell polarity, and proliferation within the DPW are important for the addition of SHF-derived cells to the heart and OFT elongation. However, the genes controlling these processes are not completely characterized. Using conditional mutagenesis in the mouse, we show that fibronectin (FN1) synthesized by the mesoderm coordinates multiple cellular behaviors in the anterior DPW. FN1 is enriched in the anterior DPW and plays a role in OFT elongation by maintaining a balance between pro- and anti-adhesive cell-extracellular matrix (ECM) interactions and controlling DPW cell shape, polarity, cohesion, proliferation, and mechanotransduction.

Intermediate-Term Clinical Outcomes of Novel Distal Tibial Rotational Osteotomy for Varus Ankle Osteoarthritis

Category: Ankle Arthritis; Ankle Introduction/Purpose: Distal tibial oblique osteotomy for ankle osteoarthritis is an effective procedure with joint preserving. However, there is the risk of nonunion due to open wedge osteotomy and complication associated with autogenous bone harvesting. We performed distal tibial rotational osteotomy (DTRO) for ankle osteoarthritis, which modified osteotomy design is expected to reduce the risk of nonunion without autologous bone grafting and soft tissue complications. We evaluated the clinical and radiographical outcome of DTRO. Methods: A total of 23 feet (4 males and 19 females) who underwent DTRO for ankle osteoarthritis in our institutions between 2016 and 2022 was included. All patients required a minimum of one year follow-up. As a surgical procedure, tri-plane osteotomy was performed using anteromedial approach. Then, the distal tibial fragment was rotated distally in the 3D plane until ankle stability was achieved, and the prominence of the medial tibia was resection after the correction. A medial tibial locking plate was applied for stabilization after filling opening gap with synthetic bone blocks. We evaluated demographic data, radiographical measurements, classification of arthritis severity, and the rate of nonunion, wound complications and reoperation. In addition, JSSF scale (Japanese Society for Surgery of the Foot ankle) and SAFE- Q (Self-Administered Foot Evaluation Questionnaire) were assessed preoperatively and at the latest follow-up. Results: Subjects had an average age of 64 years, an average follow-up period of 42 months, and were classified as stage 2/3a/3b in 1/19/2 feet preoperatively. The average of tibial anterior surface angle changed from 83.7° to 93.5°, and the tibial lateral surface angle changed from 81.0° to 81.9° in pre- and postoperative radiography. The JSSF scale significantly improved from 49.1 to 88.2 (p< 0.01) and the SAFE-Q showed significant improvement in all subscales at the latest follow-up. Bone union was obtained within 3 months in all cases, and no nonunion was observed. Delayed wound healing was observed in 1 case (4.4%). Ankle arthrodesis was needed in 1 case of deep infection and in 1 case of arthritis progression stage 3b to 4. Conclusion: In general, the distal tibia has poor soft tissue and blood flow that may lead the nonunion and soft tissue complications for distal tibial osteotomy. The advantage of DTRO was to maintain tibial bone contact after the osteotomy which may be favorable for bone stability and union, and to resect the medial bone prominence which reduce the tension of soft tissue. In this study, bone union was obtained in all cases without harvesting autogenous bone, and wound complications were low at 4.4%. Good intermediate-term outcomes were obtained, and DTRO can be a favorable surgical procedure for ankle osteoarthritis.

A Novel Sliding Knot Technique Without a Knot Pusher for Laparoscopic Pelvic Floor Surgery.

Challenges in intracorporeal knot tying can be addressed with extracorporeal slip knots, simplifying the process of tying and managing tissue tension using a knot pusher. However, existing extracorporeal knot techniques are difficult owing to their complexity, the finesse required with thin yarns, and extensive training needs. We developed a new laparoscopic extracorporeal slip knot technique that can be used with a conventional needle driver or standard clamps, offering the advantages of being cost-effective and easy to learn. The technique involves passing the active strand over another loop and securing it with the nondominant hand. A Kelly clamp is then wound around both loops three times in a tornado-like motion, passing the instrument over the active loop and under the passive one, and grasping the active strand. The passive strand is pulled to approximate the knot to the tissue and is tightened by the tension of the passive strand. This method has proven effective in various laparoscopic procedures such as sacrocolpopexy, colposuspension, pectopexy, myomectomy, and hysterectomy, facilitating surgeries without complications. The tornado knot technique is a feasible and safely locked sliding extracorporeal knot that can be easily learned, especially by surgeons who are accustomed to open surgery.

Effect of Hallux Valgus Correction Osteotomies on Flatfoot Deformity

Category: Midfoot/Forefoot; Bunion Introduction/Purpose: Flatfoot deformity is frequent in patients with hallux valgus deformity (HVD). Prior studies have shown that distal correction of HVD such as first metatarsophalangeal (MTP) fusion is capable of improving some radiologic parameters of flatfoot deformity, reinforcing the theory that the recovery of the tension of the distal medial arch is fundamental for stabilizing the first tarsometatarsal joint, preventing the arch collapse and the failure of HV correction. However, to our knowledge, it is unknown whether the first metatarsal osteotomies can generate a similar phenomenon. The purpose of this study was to evaluate if the first metatarsal osteotomies for HVD can improve the radiologic parameters of flatfoot deformity. Methods: A retrospective review of consecutive patients treated with open surgery for HVD between 2018 and 2021 at a single institution was performed. Inclusion criteria were moderate hallux valgus angle (HVA) >20º, open first metatarsal osteotomy (i.e chevron and scarf osteotomies), concomitant flatfoot deformity (Meary angle>4º), pre-and postoperative weightbearing foot radiographs, and at least 3 months of follow-up. Exclusion criteria were HVD treated with any type of first ray fusion, first MTP or TMT arthritis, prior surgery, or complications (malunion, infections). The following variables were collected by two fellowship trained-foot and ankle orthopaedic surgeons: Meary angle (MA), calcaneal pitch (CP), medial cuneiform height (MCH), talonavicular coverage angle (TNCA), anteroposterior talo-first metatarsal angle (TFMA), hallux valgus angle (HVA), and 1-2 intermetatarsal angle (IMA). The Wilcoxon signed-rank test was used to compare the variables pre and post-surgery. P value< 0.05 was considered significant. Results: A total of 225 patients were initially evaluated, of which 23 patients fulfilled the eligibility criteria. The mean age was 40.9 (+-19.1) years and all patients were female. A significant decrease was observed in the HVA and IMA (p< 0.001). The median and interquartile ranges of pre-and postoperative variables were: MA, 8.2º (6.8-12.7) to 5.7º (4.3-11.2); CP, 16.7º (13.4-20.2) to 17.5º (14.1-19.8); MCH, 27.7mm (25.9-32.5) to 29.9mm (26.4-34.2); TNCA, 19.7º (13.8-25.5) to 17.2º (13.8-22.7), and TFMA, 7.3º (6.2-9.9) to 12.3º (6.3-15.1). A significant change after first metatarsal osteotomy was observed in the MA (p=0.04), CP (p=0.03), TNCA (p=0.03), and TFMA (p=0.01), but not in the MCH. Conclusion: This study demonstrated that HVD correction through first metatarsal osteotomy is capable of significantly improving the radiological parameters commonly altered in flatfoot deformity. These findings, concordant with prior studies on first MTP fusion, reinforce the important role that soft tissue tension plays in foot alignment. However, the clinical importance and its applicability in the treatment of patients with symptomatic flat feet must be determined by future work.

Development and approval of a mobile test bench for the study of the mechanical properties of biological tissues

The determination of the mechanical properties of vessel walls and atherosclerotic plaques is a recurring issue in the numerical modelling of vessel sections. Testing machines are usually located in specialised laboratories outside medical facilities, and transporting samples from the clinic is difficult. Therefore, the task of developing mobile testing devices that can be installed directly in the clinic to perform tests immediately after surgery is relevant. This paper presents the results of the development and validation of a mobile test bench for performing mechanical experiments on uniaxial compression and tension of biological tissues. The purpose of the work is to perform mechanical tests on tissues in the clinic, avoiding their transport to the laboratory and/or freezing. Arduino UNO hardware platform is used as the control element of the test bench, which controls the main elements (motor, load cell), records data on SD card and displays information about the experiment on the computer screen. Structurally, the test bench is an analogue of a two-column testing machine. All mechanisms are assembled in a portable case, the control module is in the form of a remote plastic box. Verification of the test bench was carried out using an Instron 3342 universal testing machine with a 500 N load cell. A total of 121 soft tissue tests (including arterial wall and atherosclerotic plaque) were performed on the bench. The Young's modulus and ultimate strength values obtained are summarised in a table. The mean Young's modulus for the wall of the internal carotid artery was 0.32 ± 0.24 MPa, for soft plaque 0.30 ± 0.17 MPa, and for hard plaque 0.85 ± 0.39 MPa; a tensile strength of 1.12 ± 0.67 MPa was also determined for hard plaques in carotid arteries. The result is a unique database of tissue Young's moduli obtained from freshly collected material. The methodology and its implementation on the mobile test bench show good agreement with literature data.

Deep learning for rapid analysis of cell divisions in vivo during epithelial morphogenesis and repair.

Cell division is fundamental to all healthy tissue growth, as well as being rate-limiting in the tissue repair response to wounding and during cancer progression. However, the role that cell divisions play in tissue growth is a collective one, requiring the integration of many individual cell division events. It is particularly difficult to accurately detect and quantify multiple features of large numbers of cell divisions (including their spatio-temporal synchronicity and orientation) over extended periods of time. It would thus be advantageous to perform such analyses in an automated fashion, which can naturally be enabled using deep learning. Hence, we develop a pipeline of deep learning models that accurately identify dividing cells in time-lapse movies of epithelial tissues in vivo. Our pipeline also determines their axis of division orientation, as well as their shape changes before and after division. This strategy enables us to analyse the dynamic profile of cell divisions within the Drosophila pupal wing epithelium, both as it undergoes developmental morphogenesis and as it repairs following laser wounding. We show that the division axis is biased according to lines of tissue tension and that wounding triggers a synchronised (but not oriented) burst of cell divisions back from the leading edge.

Deep learning for rapid analysis of cell divisions in vivo during epithelial morphogenesis and repair

Cell division is fundamental to all healthy tissue growth, as well as being rate-limiting in the tissue repair response to wounding and during cancer progression. However, the role that cell divisions play in tissue growth is a collective one, requiring the integration of many individual cell division events. It is particularly difficult to accurately detect and quantify multiple features of large numbers of cell divisions (including their spatio-temporal synchronicity and orientation) over extended periods of time. It would thus be advantageous to perform such analyses in an automated fashion, which can naturally be enabled using deep learning. Hence, we develop a pipeline of deep learning models that accurately identify dividing cells in time-lapse movies of epithelial tissues in vivo. Our pipeline also determines their axis of division orientation, as well as their shape changes before and after division. This strategy enables us to analyse the dynamic profile of cell divisions within the Drosophila pupal wing epithelium, both as it undergoes developmental morphogenesis and as it repairs following laser wounding. We show that the division axis is biased according to lines of tissue tension and that wounding triggers a synchronised (but not oriented) burst of cell divisions back from the leading edge.