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Background and Objectives: Effective microsurgical training necessitates dedicated practice, prompting the development of simulation models that mitigate the hygiene risks, regulatory challenges, and storage difficulties associated with conventional biological models. This study aims to evaluate the preferences of microsurgeons and medical students regarding self-made silicone simulation vessels, comparing them to standard biological models., Methods: A three-part jig, comprising of a two-part metal clamp component and a transparent acrylic block with 4x4 channels, was designed. This assembly produced 16 vessels with a 1 ​mm inner diameter. Liquid silicone (Ecoflex 00-30), readily accessible from online distributors, was injected into the channels using a syringe. After tightening the clamp component and inserting 16 1 ​mm k-wires, the vessels were left to set for approximately 24 ​h 20 medical students with no prior microsurgical experience and 10 microsurgery-trained surgeons then evaluated these silicone vessels against a commonly used biological model (chicken brachial artery for surgeons or chicken aorta for students). Participants were then surveyed about their preference for a specific model for frequent practice using a 10-point Likert scale., Results and Conclusion: In assessing ideal microsurgical training models, all participants highlighted the importance of realism. Surgeons' main practical considerations were hygiene, availability, and setup and storage ease, while medical students were primarily concerned with cost-effectiveness. Both surgeons and medical students perceived the biological model as more realistic, yet less hygienic and harder to set up and store. Conversely, the silicone model, though deemed less realistic, offered advantages in hygiene, availability, cost-effectiveness, and setup and storage simplicity. The silicone model emerged as the overall favorite amongst all participants for frequent practice. Silicone vessels may serve as a complementary adjunct to biological models, allowing surgeons-in-training to practice their skills outside of the operating room and lab settings., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 Society for Indian Hand Surgery and Micro Surgeons. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.)

The complexity of wrist anatomy and mechanics makes it challenging to develop standardized measurements and establish a normative reference database of wrist biomechanics despite being studied extensively. Moreover, heterogeneity factors in both demographic characteristics (e.g. gender) and physiological properties (e.g. ligament laxity) could lead to differences in biomechanical behaviour even within healthy groups. We investigated the kinematic behaviour of the carpal bones by creating a virtual web-like network between the bones using electromagnetic (EM) sensors. Our objective was to quantify the changes in the carpal bones' biomechanical relative motions and orientations during active wrist motion in the form of orb-web architecture. Models from five cadaveric specimens at different wrist positions: (1) Neutral to 30° Extension, (2) Neutral to 50° Flexion, (3) Neutral to 10° Radial Deviation, (4) Neutral to 20° Ulnar Deviation, and (5) Dart-Throw Motion - Extension (30° Extension/10° RD) to Dart-Throw Motion Flexion (50° Flexion/20° UD), in both neutral and pronated forearm have been analyzed. Quantification analyses were done by measuring the changes in the network thread length, as well as determining the correlation between the threads at different wrist positions. We observed similarities in the kinematic web-network patterns across all specimens, and the interactions between the network threads were aligned to the carpal bones' kinematic behaviour. Furthermore, analyzing the relative changes in the wrist web network has the potential to address the heterogeneity challenges and further facilitate the development of a 3D wrist biomechanics quantitative tool., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Previous studies have shown that the nucleus could offer structural support to the lens capsule. This study investigated the biomechanical performance of porcine lens with and without nucleus for 4 mm, 4.5 mm, 5 mm, 5.5 mm and 6 mm capsulotomy and its potential impact on the stretch ratio of capsular bag when the anterior capsulotomy edge was stretched. Our simulation results showed higher strain for the capsular bag with nucleus, which is crucial for the porcine lens to tolerate more stretch without failure. This simulation could support future study on the optimization of capsulotomy based on patient specific condition, that is, the geometry of lens.

Background: The extent of injury in partially lacerated tendons has conventionally been expressed as a percentage of the total tendon, to justify surgical repair. We propose a more objective method to estimate the cross-sectional area of the remnant intact tendon and to determine if the remaining tendon fibers can withstand the tensile forces of early active mobilization against resistance., Methods: The study was done on 20 cadaveric specimens, which were randomly assigned to receive a laceration of 25%, 50%, or 75% of the measured transverse tendon diameter. The circumference of the remaining intact portion of the partially lacerated tendon was measured and converted using a formula to determine the derived cross-sectional area (D-CSA). These D-CSA values were then validated by comparing them to digitally measured cross-sectional areas using a computer software program (computer-measured cross-sectional area, C-CSA). In addition, the ultimate tensile strength (UTS) of these partially lacerated tendons was analyzed to determine if a threshold exists beyond which surgical repair of a partially lacerated tendon is indicated., Results: We found that the D-CSAs matched moderately with C-CSAs, with 0.622 of Pearson correlation coefficient. The UTSs of tendons with CSAs above 8 mm in circumference were consistently above 150 N., Conclusion: Measurement of the circumference of the partially lacerated tendon to obtain the D-CSA could be an accurate and practical method to benchmark residual tendon strength in the management of partially lacerated tendons., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Elaeis guineensis (Ela g, oil palm) pollen is one of the most predominant species of inhalant allergens in the tropical Southeast Asia region; however, its association with the manifestation of allergic diseases remains largely unexplored. This study aimed to determine the sensitization pattern of oil palm pollen and associate this with the risk and severity of allergic diseases., Methods: Participants were recruited as a part of the Singapore and Malaysia cross-sectional genetic and epidemiological study (SMCSGES). Two independent cohorts were recruited: n  = 564 serum samples were collected and serological assessment was performed against a panel of 16 crude inhalant allergens including house dust mite, pet, insect, pollen, and fungal allergens; n  = 13 652 Singapore/Malaysia Chinese young adults were recruited and skin prick test was used to assess oil palm sensitization, which was tested for its association with the risk and severity of asthma, allergic rhinitis (AR), and atopic dermatitis (AD)., Results: The sensitization rate of oil palm pollen is 9.6% in the n  = 564 Singapore/Malaysia cohort. In the n  = 13 652 Singapore/Malaysia Chinese cohort, oil palm sensitization significantly associates with increased risks of asthma ( p  = 1.34x10 -4 ), AR ( p  = 2.91x10 -13 ), and AD ( p  = 6.95x10 -7 ). Asthmatic patients with oil palm sensitization have increased risks of wheezing ( p  = 0.00995), nocturnal cough ( p  = 0.0122), and exacerbations ( p  = 0.00139) in the past 12 months. AR patients with oil palm sensitization also have an increased risk of developing moderate-to-severe symptoms ( p  = 0.00113)., Conclusions: We have identified significant associations of oil palm sensitization with increased risks, exacerbations, and the severity of symptoms of allergic diseases in the tropical Southeast Asian region (Singapore/Malaysia)., Competing Interests: F.T.C. has received consulting fees from Sime Darby Technology Centre; First Resources Ltd; Genting Plantation, and Olam International, outside the submitted work. All funding agencies had no role in the study design, data collection, analysis, decision to publish, or preparation of the manuscript. The other authors declare no competing interests., (© 2023 The Authors.)

Background: We see increasing evidence that dietary and nutrients factors play a pivotal role in allergic diseases and recent global findings suggest that dietary habits influence the pathogenesis of atopic dermatitis (AD). Frequent consumption of fast food diets is associated with AD development. Despite the rising prevalence of AD in Asia, efforts in investigating the role of dietary habits and AD in adults are still lacking., Methods: We evaluated the association between the dietary intake of 16 food types and AD manifestations using our Singapore/Malaysia Cross-sectional Genetics Epidemiology Study (SMCGES) population. Dietary habits profiles of 11,494 young Chinese adults (1,550 AD cases/2,978 non-atopic controls/6,386 atopic controls) were assessed by an investigator-administered questionnaire. AD cases were further evaluated for their chronicity (550 chronic) and severity (628 moderate-to-severe). Additionally, we derived a novel food index, Quality of Diet based on Glycaemic Index Score (QDGIS), to examine the association between dietary intake of glycaemic index (GI) and various AD phenotypes., Results: The majority of AD subjects are distributed in the good (37.1%) and moderate (36.2%) QDGIS classes. From the multivariable analyses for age and gender, a moderate QDGIS class was significantly associated with a lower odds of AD (adjusted odds ratio (AOR): 0.844; 95% confidence interval (CI): 0.719-0.991; p < 0.05) and moderate-to-severe AD (AOR: 0.839; 95% CI: 0.714-0.985; p < 0.05). A good QDGIS class was only significantly associated with a lower odds of chronic AD (AOR: 0.769; 95% CI: 0.606-0.976; p < 0.05). Among high GI foods, frequent consumption of burgers/fast food was strongly associated with an increased risk of chronic and moderate-to-severe AD. Among low GI foods, increased intake frequencies of fruits, vegetables, and pulses decreased the odds of AD. Finally, we identified significant associations between frequent seafood, margarine, butter, and pasta consumption with an increased odds of AD despite them having little GI values., Conclusion: While genetic components are well-established in their risks associated with increased AD prevalence, there is still a lack of a focus epidemiology study associating dietary influence with AD. Based on the first allergic epidemiology study conducted here in Singapore and Malaysia, it laid the groundwork to guide potential dietary interventions from changing personal dietary habits., (© 2023 The Author(s). Published by S. Karger AG, Basel.)

This study aimed to compare the torsional resistance of three fixation techniques for spiral metacarpal fractures: screw-only fixation, screw plus neutralization plate fixation, and a locking plate construct. A spiral fracture was created on 18 cadaveric metacarpal bones by applying an axial and torsional loading force using an Instron 3343 mechanical tester. The failure strength was defined as the native torque strength. The fractures were divided into three groups and fixed using each of the three techniques. The repaired bones were loaded to failure to determine the post-repair strength. The neutralization plate group conferred a post-repair torque (278.6 Nmm) that was similar to the native torque (292 Nmm) with a diminution of only 4.5% and appeared to provide the best resistance to torsion., Competing Interests: Declaration of conflicting interestsThe authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Excitons (coupled electron-hole pairs) in semiconductors can form collective states that sometimes exhibit spectacular nonlinear properties. Here, we show experimental evidence of a collective state of short-lived excitons in a direct-bandgap, atomically thin MoS 2 semiconductor whose propagation resembles that of a classical liquid as suggested by the nearly uniform photoluminescence through the MoS 2 monolayer regardless of crystallographic defects and geometric constraints. The exciton fluid flows over ultralong distances (at least 60 μm) at a speed of ~1.8 × 10 7  m s -1 (~6% the speed of light). The collective phase emerges above a critical laser power, in the absence of free charges and below a critical temperature (usually T c  ≈ 150 K) approaching room temperature in hexagonal-boron-nitride-encapsulated devices. Our theoretical simulations suggest that momentum is conserved and local equilibrium is achieved among excitons; both these features are compatible with a fluid dynamics description of the exciton transport., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Understanding the stresses on the scapholunate interosseous ligament (SLIL) and its interaction with synovial fluid pressure could be vital to improve wrist treatment for various wrist conditions such as arthritis, sprains and tendonitis. This study investigated the interaction between the intra-articular pressure, specifically the synovial fluid pressure change and the SLIL stresses in a computational model during wrist radioulnar deviation (RUD). Magnetic resonance imaging (MRI) scans were used to acquire the anatomical model of the carpal bones and ligament, while the kinematics of scaphoid and lunate were obtained through dynamic computerized tomography (CT) scans. A two-way fluid-structure interaction (FSI) was used to model the dynamics between the scaphoid and lunate, the SLIL, and the synovial fluid. The synovial fluid pressure change was found to be small (-4.86 to 3.23 Pa) and close to that simulated in a previous work without the SLIL (-1.68 to 2.64 Pa). Furthermore, peaks of maximum fluid pressure were found to trail the peaks of ligament stress. Therefore, it is suggested that the influence of synovial fluid pressure on the ligament in the SLIL model is negligible and simulations of the scapholunate joint could forego fluid-structure interactions. Future studies can instead explore other structures in the carpus that can possibly contribute to the ligament stresses. Clinically, treatments can be targeted at these areas to help prevent or slow the progression of ligament injuries into serious consequences like the degenerative joint disease.

Introduction: Commercially available tourniquets are ill-suited for paediatric patients with limb circumferences smaller than the required mechanism, forcing surgeons to improvise. This study aimed to quantify pressures exerted by the Penrose tourniquet when applied on a phantom model and evaluate the intra-/inter-rater reproducibility of the technique previously proposed., Methods: Eight calibrated pressure sensors were distributed evenly along the inner and outer circumference of a silicon-based model. A 30cm-by-3.2 cm ARGYLE Penrose drain, 4-by-4 gauze, marker and ruler were used. The optimal interval for arterial occlusion was determined to be 70% of limb circumference. The tourniquet was secured using two half-knots formed by gauze., Results: Two-turns of the tourniquet about the model generated mean pressures (SD) of 209.43 (SD:35.98 mmHg) (95%CI: 195.85-224.00 mmHg) (outer-sensor) and 246.32 (SD:61.92 mmHg) (95%CI: 221.02-273.49 mmHg) (inner-sensor). Three-turns generated mean pressures of 302.07 (SD:23.98 mmHg) (95%CI: 292.29-312.53 mmHg) (outer-sensor) and 314.44 (SD:56.70 mmHg) (95%CI: 291.25-338.25 mmHg) (inner-sensor)., Conclusion: The Penrose tourniquet has clinical utility, particularly for patients where commercially available tourniquets are not suitable. Current application techniques generate inconsistent pressures. Using the existing model, further refinement can be done to improve the consistency and safety of the application. We recommend using intervals of slightly more than 70% of limb circumference and only two turns of the Penrose tourniquet during application., Level of Evidence: V., Competing Interests: Conflict Of Interest Statement This manuscript has been seen and approved by all authors for the submission. Furthermore, this manuscript has not been published and is not under consideration for publication elsewhere. We have no conflicts of interest to disclose., (Copyright © 2023. Published by Elsevier Ltd.)

Background: This review aims to identify publications on quantitative biomechanical testing of surgical knot security and the physical factors that determine knot security and failure., Materials and Methods: An electronic literature search was performed in accordance with PRISMA guidelines in January 2022 utilizing the PubMed and Google Scholar databases to look for objective biomechanical studies on knot security in surgery using the primary terms 'knot security' and 'biomechanical testing'., Results: Thirty-six articles were included. Twenty-four configurations of surface, laparoscopic, and arthroscopic knots were studied. Biomechanical tensile testing was used to evaluate knot security in vitro . Load to failure (N) and elongation at knot failure (mm) were quantified by static and cyclic testing to evaluate the knot holding capacity and failure mechanism of slippage or rupture., Conclusion: This review reassures that the knot configuration, suture materials, suture sizes, and number of throws are key factors in determining the knot's security. Knot configuration has to be simple for laparoscopic and arthroscopic knots due to the confined space of the operating site. With the advent of stronger suture materials for high-tension surgical reconstructive procedures, there is an unmet need to understand the physical behavior of the knot and the factors that determine its resistance to slippage or rupture.Level of Evidence: Level IV., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Introduction: Previous studies have indicated the ERBB2 genetic variants in the 17q12 locus might be associated with asthma; however, the functional effects of these variants on asthma risk remain inconclusive. This study aimed to characterize the functional roles of asthma-associated ERBB2 single nucleotide polymorphisms (SNPs) in asthma pathogenesis by performing genetic association and functional analysis studies., Methods: This study belongs to a part of an ongoing Singapore/Malaysia cross-sectional genetics and epidemiological study (SMCSGES). Genotype-phenotype associations were assessed by performing a genotyping assay on n = 4,348 ethnic Chinese individuals from the SMCSGES cohort. The phosphorylation levels of receptors and signaling proteins in the MAPK signaling cascades, including ErbB2, EGFR, and ERK1/2, were compared across the genotypes of asthma-associated SNPs through in vitro and ex vivo approaches., Results: The ERBB2 tag-SNP rs1058808 was significantly associated with allergic asthma, with the allele "G" identified as protective against the disease (adjusted logistic p = 6.56 × 10-9, OR = 0.625, 95% CI: 0.544-0.718). The allele "G" of rs1058808 resulted in a Pro1170Ala mutation that results in lower phosphorylation levels of ErbB2 in HaCat cells (p < 0.001), whereas the overall ERBB2 mRNA expression and the phosphorylation levels of EGFR remained unaffected. In the SMCSGES cohort, individuals carrying the genotype "GG" of rs1058808 had lower phosphorylated ERK1/2 proteins in the MAPK signaling cascade. A lower phosphorylation level of ERK1/2 was also associated with reduced asthma risk., Conclusions: The present findings highlighted the involvement of a functional exonic variant of ERBB2 in asthma development via modulating the MAPK signaling cascade., (© 2023 The Author(s). Published by S. Karger AG, Basel.)

Background: Atopic Dermatitis (AD) is a highly pruritic, chronic-recurrent inflammatory skin condition associated with erythematous lesions that affect a significant proportion of the population. Although AD is a non-communicable disease, it can cause pain, unbearable itchiness, sleep disturbance, loss of work productivity, and reduced quality of life. As a heterogeneous disease, AD is influenced by multiple genes and environmental triggers. As such, it is imperative to gain a deeper insight into the intricate gene-environment relationship that results in the manifestation of AD., Methods: There are 3 objectives in our study. We first aim to update the epidemiological status of AD amongst young adults in Singapore and Malaysia, in particular amongst the Chinese ethnic background. Next, we re-evaluated the possible associated risk factors, identified in our previous meta-analysis and review studies, on the current cohort. Finally, we described here a detailed disease presentation and symptoms profile of our Singapore and Malaysia Cross-Sectional Genetics Epidemiology Study (SMCGES) cohort, which forms the base population for the discovery of associated genetic factors in relation to asthma, allergic diseases and skin conditions. Based on a skin prick test (SPT) and investigator-administered medical history responses, we assessed the AD profiles of 11 494 participants and the significant modifiable and non-modifiable factors associated with disease presentation., Results: The prevalence of AD in the combined population was 13.5%. Chronic and moderate/severe AD were observed in 35.5% and 40.5% of the individuals with AD, respectively. Family history of atopic diseases, prior history of drug allergies, a history of acne, increased household family monthly income, higher number of individuals in the shared household, parental education, sedentary lifestyle, physical activities, alcoholic consumption, and even quality of diet was significantly associated with AD presentation, chronicity, and severity. Among all the factors evaluated, family and personal history of atopic diseases imposed the strongest associated risk., Conclusions: These findings supported our previous review studies and affirmed that familial history or genetic factors critically influence the development of AD in our population and environment. Environmental and other modifiable factors can also trigger AD throughout the lifetime of individuals who have especially inherited the atopic disease disposition. A better understanding of how these risk factors affect AD individuals in our population can facilitate disease surveillance, monitor disease control, and serve as a description for our future genetic epidemiology studies., (© 2022 The Author(s).)

Background: Allergic rhinitis (AR) is characterized by the occurrence of at least 2 symptoms of nasal itching, nasal blockage, rhinorrhea, and sneezing, when not afflicted with a cold or flu, with defined atopic sensitization demonstrated by skin prick test or specific IgE responses. Besides the detriment to standard of living and economic burden of AR, both multicentre and single-cohort studies have observed an increase in AR prevalence in Asia over time., Methods: In total, 12 872 individuals, with mean age 22.1 years (SD = 4.8), were recruited from universities in Singapore and Malaysia. Each participant provided epidemiological data based on an investigator-administered questionnaire adapted from the validated International Study of Allergies and Asthma in Childhood (ISAAC) protocol, and atopy status was determined using a skin prick test (SPT) performed by qualified staff. AR was diagnosed according to Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines and a positive SPT result., Results: Sensitization (determined by SPT) to either Blomia tropicalis or Dermatophagoides pteronyssinus was prevalent in 66.5% of the cohort. Current rhinitis (manifesting ≥2 rhinitis symptoms, within the past 12 months) was observed in 48.9% of our population, while AR, which included atopy status, was estimated at 39.4%. Sneezing and rhinorrhea were the most common symptoms among AR cases. AR prevalence decreased with increasing age (OR: 0.979; 95% CI: 0.969-0.989), while male gender (OR: 2.053; 95% CI: 1.839-2.294), and a parental history of allergic diseases (OR: 2.750; 95% CI: 2.284-3.316) were significant risk factors for AR. Upon adjustment for age, gender, and parental history, housing type (OR: 0.632; 95% CI: 0.543-0.736) and income level (>$6000 vs <$2000; OR: 2.461; 95% CI: 2.058-2.947) remained as significant risk factors for AR, while ever having kept a pet (OR: 1.167; 95% CI: 1.025-1.328) emerged as a risk factor. Conflicting results were obtained for indicators of sedentary lifestyle: frequent physical activity (OR: 1.394; 95% CI: 1.150-1.694) and increased duration spent using the TV/computer (OR: 1.224; 95% CI: 1.006-1.489) both increased the risk of AR. Lastly, we used the Quality of Diet based on Glycaemic Index Score (QDGIS) to assess the Glycaemic Index (GI) level of overall diet. We identified lower GI level of overall diet as a protective factor against AR manifestation (OR: 0.682; 95% CI: 0.577-0.807)., Conclusion: While the previously established non-modifiable risk factors for AR were present in our study population, the identification of modifiable risk factors, such as TV/computer usage, and dietary habits, opens a new area for research, both in the areas of gene-environment interaction, and management of AR., (© 2022 The Author(s).)

Background: Multi-strand repair of flexor tendons are important for increased strength but this may cause ischemia during the intrinsic healing process. In this study, we aim to compare the strength of the 4-strand modified Asymmetric repair using 2-0 Tenoflex ® suture with the original description of the Asymmetric repair using a 6-strand 4-0 Supramid ® suture under cyclic loading in a porcine tendon model. We hypothesise that the number of core sutures through the repair site can be reduced with advanced suture material. Methods: Two groups consisting of 10 porcine tendons each were repaired using the Asymmetric repair technique. One group underwent the original description using a 6-strand 4-0 Supramid ® suture and the other group underwent a modified 4-strand technique using 2-0 Tenoflex ® suture. The repaired tendons were subjected to a two-stage cyclic loading test. Survival rate and gap formation at the repaired site were analysed. The failure mechanism of each repair was also analysed. Additionally, the cross-sectional area of each strand of core suture used was also calculated. Results: The 1st and 2nd stage survival rates were 90% and 30% for the 6-strand repair and 100% and 60% for the 4-strand repair respectively. The mean gap formation at the end of stage 2 was 1.79 mm (SD 1.57) for the 4-strand repair, which is comparable to that of the 6-strand repair (1.82 mm; [SD 1.20]). The total mean cross-sectional area of 2-0 Tenoflex ® and 4-0 Supramid ® suture strands were 0.078 and 0.086 mm 2 , respectively. Conclusions: These results demonstrate that despite having fewer core sutures, the 4-strand modified Asymmetric repair using 2-0 Tenoflex ® may be a better option as compared to the original 6-strand Asymmetric repair using 4-0 Supramid ® .

While the IGF1/FoxO1/mTORC1 signalling pathway is a well-established nutrigenomic link between high glycaemic index (GI)/glycaemic load (GL) diet and acne vulgaris, other signalling pathways remain elusive. Therefore, we aimed to investigate other genes that are involved in the high GI/GL diet-acne link, using our Singapore/Malaysia population epidemiological, genomics and transcriptomics data. High GI/GL dietary habit of 3207 acne cases (1869 and 1341 further classified into severity and scarring grades, respectively) and 2521 controls were evaluated based on Quality of Diet based on Glycaemic Index Score (QDGIS). Overlapping concordant differentially expressed genes (DEGs) between acne case-controls and QDGIS poor-moderate/good classes were identified from whole-transcriptome sequencing data of PBMC of a subset of participants. Finally, we assessed the expression quantitative trait loci (eQTL) association of single nucleotide polymorphisms (SNPs) of the concordant DEGs. Daily intake of fruits significantly reduced the risk of acne presentation, severity and scarring by up to 48.5%. Those with good QDGIS had significantly lower risk of mild and moderate/severe acne, and grade 1/2 acne scarring. Sequential filtering identified four overlapping concordant DEGs that were significantly associated with acne and QDGIS, namely GOLGA7B, SNCB, LOC102723849 and LOC283683. Combining transcriptome and genetic association data, we identified intronic SNP rs1953947 in GOLGA7B as an eQTL for acne. In conclusion, we identified GOLGA7B as a plausible novel gene that links high GI/GL with acne, and hence propose a model for the involvement of Golga7b in high GI/GL diet-acne pathogenesis, which includes palmitoyl acyltransferase zDHHC5, fatty acid translocase CD36 and palmitic acid., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Massachusetts General Hospital (MGH) repair is one of the widely used 4-strand flexor tendon repair techniques. However, it uses two single strand sutures that are each passed twice across the repair site. This is time consuming and may cause imbalance of the load across the repair. We modified the MGH repair by using a looped suture and call it the looped MGH repair. The aim of this study is to compare the strength of the looped MGH repair performed with three different looped sutures against the strength of original MGH repair. Methods: Forty porcine flexors were used for the study. The original MGH repair was performed with Prolene ® 4-0. Looped MGH repair was performed with three different loop sutures, Supramid ® 4-0, Tendo-Loop ® 4-0 and FiberLoop ® 4-0. Mechanism of failure, ultimate tensile strength, stiffness, load to 2-mm gap formation and repair time were recorded for comparison. Results: There was no significant difference between the original MGH repair and the looped repair using Supramid ® regarding their biomechanical performance. Looped MGH repair using Tendo-Loop ® and FiberLoop ® showed significantly higher ultimate tensile strength and FiberLoop ® had highest 2-mm gap force. All looped MGH repairs required significant less time compared to original MGH repair. Conclusions: Our modification of the MGH repair using a looped Supramid ® 4-0 suture took significantly lesser time to perform while providing the same strength as the original MGH repair using Prolene ® 4-0. The use of the FiberLoop ® 4-0 provided significantly greater strength while taking lesser time.

Background: Early active motion protocols have shown better functional outcomes in zone II flexor tendon lacerations. Different techniques of tendon repair have different effects on gliding resistance, which can impact tendon excursion and adhesion formation. For successful initiation of early active mobilisation, the repair technique should have high breaking strength and low gliding resistance. Previous studies have shown the Modified Lim-Tsai technique demonstrates these characteristics. The Asymmetric repair has also shown superior ultimate tensile strength. This study aims to compare the gliding resistance between the two techniques. Methods: FDP tendons from ten fresh frozen cadaveric fingers were randomly divided into two groups, transected completely distal to the sheath of the A2 pulley and repaired using either the Modified Lim-Tsai or Asymmetric technique. The core repair was performed with Supramid 4-0 looped sutures and circumferential epitendinous sutures were done with nylon monofilament Prolene 6-0 sutures. The gliding resistance and ultimate tensile strength were then tested. Results: The gliding resistance of the Asymmetric and Modified Lim-Tsai repair techniques were 0.2 and 0.95 N respectively. This difference was significant ( p = 0.008). The Modified Lim-Tsai technique had a higher ultimate tensile strength and load to 2 mm gap formation, though this was not significant. Conclusions: Gliding resistance of the Asymmetric repair is significantly less than that of Modified Lim-Tsai. Ultimate tensile strength and load to 2 mm gap formation are comparable.

Background : The asymmetric technique for flexor tendon repairs has various advantages but further improvement is possible by using a suitable suture material. In this study, we compare the biomechanical performance of asymmetric repairs using 3 suture materials: Supramid Extra II 4-0, Tendo-Loop 4-0, and FiberLoop 4-0. Methods : We divided 30 porcine flexor tendons into 3 arms. Each arm of tendons were repaired by using 1 of the 3 proposed suture materials. Each repaired tendon was tested by using a mechanical tester. Ultimate tensile strength (UTS), load to 2 mm gap force, failure mechanism and stiffness of the tendons were investigated. Results : FiberLoop® achieved the highest UTS (90.4 ± 17.9 N), followed by Tendo-Loop (85.3 ± 10.3 N). The difference was no statistically significant. The UTS of repairs using Supramid® was significantly lower (64.0 ± 8.4 N). For load to 2 mm gap force, FiberLoop® achieved 20.7 ± 4.8 N while Tendo-Loop® had 20.5 ± 4.2 N. The difference was also no statistically significant. The repairs using Supramid® had a significantly lower load to 2 mm gap force of 14.2 ± 2.7 N. The stiffness of asymmetric repairs using FiberLoop® and Tendo-Loop® was 5.64 ± 1.7 N/mm and 5.63 ± 0.7 N/mm. The difference was also no statistically significant. The repairs using Supramid® had a significantly lower stiffness of 4.15 ± 1.0 N/mm. Failure mechanisms for the repaired specimens were reported as such: Supramid had 100% suture rupture; Tendo-Loop had 90% suture rupture and 10% suture pullout; FiberLoop had 20% suture rupture and 80% suture pullout. Conclusions : The asymmetric repair configuration is able to produce superior biomechanical performance by using Tendo-Loop® or FiberLoop®. Improvement of the asymmetric technique by using Tendo-Loop® or FiberLoop® could potentially contribute to better surgical outcomes of flexor tendon repair.

Background: Insects models are excellent models of the innate immune system, as they are free from the influences of vertebrate adaptive immunity. Crickets are hemimetabolous insects belonging to the order Orthopteran order that have not been as extensively characterized as other holometabolous insects, and may provide new insights into the insect immune responses. In this study, we aim to characterize the innate immune responses of the common house cricket, Acheta domesticus in response to a human pathogenic bacterium E. coli K1., Methods: Crickets were injected with sterile buffer, live E. coli K1 or heat-killed E. coli K1. Physiological effects such as mortality and weight change of the crickets were determined 24-, 48- and 72-h post injection while immunological effects such as hemocyte counts, bacteremia, phenoloxidase and lysozyme activity of the crickets were measured at 2- and 24-h post-injection., Results: The injection of E. coli K1 in crickets resulted in >85% mortality 3-days post injection, accompanied by significant weight loss. E. coli K1 injection caused a significant increase in both phenoloxidase and lysozyme activities in cricket hemolymphs 24-h post injection. Live E. coli K1 injected crickets resulted in a significant reduction in circulating hemocytes 24-h post injection which was not observed in other treatment groups. This was consistent with the resolution of bacteremia observed 24-h post infection in live E. coli K1 injected crickets., Conclusion: Our study provides new insights on the innate immune response to pathogenic E. coli K1 in a cricket model., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest., (Copyright © 2021 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.)

Introduction: Medial migration of the femoral neck element (FNE) superomedially against gravity with respect to the intramedullary component of the cephalomedullary nail is a complication increasingly recognized to cause femoral head cut-out in intramedullary nailing of pertrochanteric hip fractures. Although cut-outs are common to both intra- and extramedullary fixation, especially in unstable pertrochanteric hip fractures, FNE medial migration in sliding hip screws continues to remain sparse despite increased awareness of the phenomenon. This study aims to investigate whether intramedullary nailing is biomechanically predisposed to FNE medial migration compared to extramedullary fixation with sliding hip screws to account for the discrepancy in reported FNE medial migration rates., Materials and Methods: Twelve fourth-generation synthetic femurs (Sawbones) with unstable intertrochanteric fractures were divided into 2 groups (n=6 per group). Fracture fixation was performed using the Proximal Femoral Nail Antirotation (PFNA, Synthes) (n=6) in the first group, and the Dynamic Hip Screw (DHS, Synthes) (n=6) in the second group. Both groups were subjected to bidirectional cyclic loading (600N compression loading, 120N tensile loading) at 2 Hz for 5000 cycles. The medial migration distance (MMD) was recorded at the end of the testing cycles., Results: The mean MMD in the PFNA group was 4.56mm (SD 0.69mm) with consistent reproduction of medial migration across all constructs tested. This was significantly more compared to the MMD of 1.17mm (SD 0.69mm) in the DHS group (p<0.001)., Conclusion: Intramedullary nailing of unstable intertrochanteric hip fractures is inherently predisposed to FNE medial migration making it more susceptible to consequent cut-out compared to fixation with the DHS., Competing Interests: Declaration of Competing Interest None, (Copyright © 2021. Published by Elsevier Ltd.)

Fungal spores and conidia are the major components of total airspora in the tropical Asia environment, and their sensitization patterns are often associated with allergic diseases such as asthma, allergic rhinitis (AR), and atopic dermatitis. Hence, we recruited a cross-sectional cohort of 9223 Singapore/Malaysia Chinese adults and assessed their sensitization against Curvularia lunata allergen using the skin prick test approach. A subset of this cohort (n = 254) was also screened for specific Immunoglobulin E (sIgE) titers against a panel of 11 fungal allergens. We found significant association of Curvularia lunata sensitization with the risk of asthma (OR = 1.66, 95% CI: 1.17-2.33; p = 0.00391) and AR (OR = 1.69, 95% CI: 1.18-2.41; p = 0.00396). Among asthmatic patients (n = 1680), Curvularia lunata sensitization also increased frequencies of wheezing symptoms (OR = 1.81, 95% CI: 1.05-2.96; p = 0.0239), general practitioner/specialist visits (OR = 2.37, 95% CI: 1.13-4.61; p = 0.0157), and other asthma-related exacerbation events (OR = 2.14, 95% CI: 1.04-4.10; p = 0.0289). In our serum cohort, sensitization to Aspergillus spp. was the most common fungal sensitization, with 23.6% (n = 60) had a class 3 and above sensitization (positive sensitization; sIgE titers of > 3.5 kU/L) against this allergen. Increasing sIgE titer against Aspergillus spp. was also correlated with increased AR risk and AR-related symptoms. In conclusion, our findings emphasize an important role of fungal sensitization in the manifestations of asthma and AR in the Southeast Asian Chinese population., (© 2021. The Author(s).)

Background: Acne vulgaris, a highly prevalent multifactorial inflammatory skin disease, can be categorised into different severity and scarring grades based on the type, number, and severity of lesions. While many epidemiology studies have investigated the risk factors for acne presentation, fewer studies have specifically studied the risk factors for acne severity and scarring. Therefore, this study investigated the prevalence of acne, acne severity and scarring grades, and their associated non-modifiable and modifiable epidemiological risk factors among Malaysian Chinese., Methods: A total of 1840 subjects (1117 cases/723 controls) completed an investigator-administered questionnaire as part of a cross-sectional study, which include socio-demographics, familial history, lifestyle factors, dietary habits, and acne history. Acne cases were further evaluated for their severity (n = 1051) and scarring (n = 1052) grades by a trained personnel., Results: Majority of the acne cases (up to 69%) had mild acne or Grade 1/2 scarring, while 21.6% had moderate/severe acne and 5.5% had Grade 3/4 scarring. Males had significantly higher risk of presenting with higher grades of acne scarring. Those who had acne, regardless of severity and scarring grades, had strong positive familial history (either in parents and/or sibling). Frequent consumption (most or all days) of foods that are commonly consumed during breakfast (butter, probiotic drinks, cereals and milk) decreased the risk for acne presentation and higher acne scarring, while periodic consumption (once/twice per week) of nuts and burgers/fast food decreased the risk for higher acne severity. Alcohol drinking was significantly associated with increased risk for acne presentation, while paternal, parental and household smoking were associated with reduced risk of more severe acne., Conclusions: In conclusion, positive familial history is a strong predisposing factor in influencing acne presentation, severity and scarring. Frequent consumption of foods that are commonly consumed during breakfast is protective against acne presentation.

The introduction of femtosecond laser-assisted cataract surgery is an alternative approach to conventional cataract surgery. Our study aimed to determine the effectiveness of femtosecond laser-assisted capsulotomy in the presence of different ophthalmic viscoelastic devices (OVDs) in the anterior chamber. Fresh porcine eyes (n = 96) underwent LDV Z8-assisted anterior capsulotomy, either in the presence of an OVD (Viscoat, Provisc, Healon, Healon GV or HPMC) or without, using 90% and 150% energies respectively. Following that, the capsule circularity, tag's arc-length, tag-length, tag-area and rupture strength (mN) of the residual capsular bag were evaluated. We found that increasing energy from 90 to 150% across the OVD sub-groups improved the studied capsulotomy parameters. Amongst the 90% energy sub-groups, the circularity and tag-parameters were worse with Viscoat and Healon GV, which have higher refractive index and viscosity compared to the aqueous humour. Using 150% energy, Healon GV showed a significantly worse total arc-length (p = 0.01), total tag-length (p = 0.03) and total tag-area (p = 0.05) compared to the control group. We concluded that; an OVD with a refractive index similar to aqueous humour and lower viscosity, such as Healon or Provisc, as well as a higher energy setting, are recommended, to enhance the efficacy of laser capsulotomy.

Purpose: The aim of this study was to (1) develop suture techniques in repairing radial meniscal tear; (2) to compare the biomechanical properties of the proposed repair techniques with the conventional double horizontal technique., Methods: Thirty-six fresh-frozen porcine medial menisci were randomly assigned into four groups and a complete tear was made at the midline of each meniscus. The menisci were subsequently repaired using four different repair techniques: double vertical (DV), double vertical cross (DVX), hybrid composing one vertical and one horizontal stitch, and conventional double horizontal (DH) suture technique with suturing parallel to the tibia plateau. The conventional double horizontal group was the control. The repaired menisci were subjected to cyclic loading followed by the load to failure testing. Gap formation and strength were measured, stiffness was calculated, and mode of failure was recorded., Results: Group differences in gap formation were not statistically significant at 100 cycles (p = .42), 300 cycles (p = .68), and 500 cycles (p = .70). A trend was found toward higher load to failure in DVX (276.8 N, p < .001), DV (241.5 N, p < .001), and Hybrid (237.6 N, p < .001) compared with DH (148.5 N). Stiffness was also higher in DVX (60.7 N/mm, p < .001), DV (55.3 N/mm, p < .01), and Hybrid (52.1 N/mm, p < .01), than DH group (30.5 N/mm). Tissue failure was the only failure mode observed in all specimens., Conclusion: Our two proposed vertical suture techniques, as well as the double vertical technique, had superior biomechanical properties than the conventional technique as demonstrated by higher stiffness and higher strength.

Background: Surgical stabilization of rib fractures is an established form of treatment for complex rib fractures. Plate fixation with bicortical screws placement can cause injury to intra-thoracic organs and pleural irritation from protruding screw tips. The aim of this study is to compare the biomechanical properties of monocortical and bicortical plate fixation for rib fractures using a locking plate system., Methods: Ten pairs of fresh-frozen cadaveric ribs were harvested. Native ribs were mounted onto a biomechanical tester and statically loaded to failure to induce a rib fracture. The native stiffness of the rib was measured. Next, the ribs were stabilized using the Synthes MatrixRIB (Johnson & Johnson, USA) locking plate. Left-sided ribs were fixed in a bicortical manner and right-sided ribs were fixed in a monocortical manner. The repaired ribs were subjected to cyclic loading of 50,000 cycles between 2 to 6 N to simulate physiological respiration, followed by static loading at a rate of 10 N/min until failure. The pre and post-repaired stiffness were measured. A high-speed camera was used to record the mechanism of failure., Results: One left-sided rib was omitted from the study because the fracture occurred at the drill hole site. Left-sided ribs demonstrated a mean native stiffness of 10.0 N/mm (SD 3.71) and right-sided 11.92 N/mm (SD 3.57). After plate fixation, pre and post cyclic stiffness was 3.32 N/mm (SD 1.21) and 4.41 N/mm (SD 3.29) for the bicortical group; 3.14 N/mm (SD 1.24) and 3.91 N/mm (SD 1.98) for the monocortical group. There is no statistical difference found between the two groups (P=0.872)., Conclusions: Our results show that there is no difference in stability between monocortical and bicortical fixation for rib fractures using a locking plate system. Monocortical fixation is recommended to avoid potential complications., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare., (2019 Journal of Thoracic Disease. All rights reserved.)

Background: This study investigates the biomechanical performance of the Asymmetric flexor tendon repair technique using barbed suture. The Asymmetric repair technique using monofilament nylon suture was previously reported to have a higher tensile strength than the modified Lim-Tsai repair technique, but its repair stiffness and load to gap force were significantly lower. There is hence an unmet need to improve this technique and the substitution of nylon suture with barbed sutures may be the solution. Methods: Two groups consisting of 10 porcine tendons each were repaired with the six-strand Asymmetric repair technique using V-Loc ® 3-0 and Supramid ® 4-0 respectively. The repairs were subjected to a mechanical tester for static testing. The ultimate tensile strength, load to 2 mm gap force, repair stiffness, time taken to complete a repair and failure mechanism of the repairs were recorded and analyzed. Results: All the repairs using V-Loc ® 3-0 sutures had significantly higher median values of ultimate tensile strength (64.1 N; 56.9 N), load to 2 mm gap force (39.2 N; 19.7 N), repair stiffness (6.4 N/mm; 4.7 N/mm) and time taken to complete a repair (9.4 mins; 7.7 mins). All the repairs using V-Loc ® sutures failed by suture breakage while 80% of repairs using Supramid ® sutures failed by suture pullout. Conclusions: The use of the barbed sutures in the Asymmetric repair technique, whilst more time consuming, has shown promising improvement to its biomechanical performance (i.e. better ultimate tensile strength, stiffness and resistance to gap formation).

Objectives: The paradoxical migration of the femoral neck element (FNE) superomedially against gravity, with respect to the intramedullary component of the cephalomedullary device, is a poorly understood phenomenon increasingly seen in the management of pertrochanteric hip fractures with the intramedullary nail. The aim of this study was to investigate the role of bidirectional loading on the medial migration phenomenon, based on unique wear patterns seen on scanning electron microscopy of retrieved implants suggestive of FNE toggling., Methods: A total of 18 synthetic femurs (Sawbones, Vashon Island, Washington) with comminuted pertrochanteric fractures were divided into three groups (n = 6 per group). Fracture fixation was performed using the Proximal Femoral Nail Antirotation (PFNA) implant (Synthes, Oberdorf, Switzerland; n = 6). Group 1 was subjected to unidirectional compression loading (600 N), with an elastomer (70A durometer) replacing loose fracture fragments to simulate surrounding soft-tissue tensioning. Group 2 was subjected to bidirectional loading (600 N compression loading, 120 N tensile loading), also with the elastomer replacing loose fracture fragments. Group 3 was subjected to bidirectional loading (600 N compression loading, 120 N tensile loading) without the elastomer. All constructs were tested at 2 Hz for 5000 cycles or until cut-out occurred. The medial migration distance (MMD) was recorded at the end of the testing cycles., Results: The MMDs for Groups 1, 2, and 3 were 1.02 mm, 6.27 mm, and 5.44 mm respectively, with reliable reproduction of medial migration seen in all groups. Bidirectional loading groups showed significantly higher MMDs compared with the unidirectional loading group (p < 0.01)., Conclusion: Our results demonstrate significant contributions of bidirectional cyclic loading to the medial migration phenomenon in cephalomedullary nail fixation of pertrochanteric hip fractures. Cite this article : G. W. Law, Y. R. Wong, A. K-S. Yew, A. C. T. Choh, J. S. B. Koh, T. S. Howe. Medial migration in cephalomedullary nail fixation of pertrochanteric hip fractures: A biomechanical analysis using a novel bidirectional cyclic loading model. Bone Joint Res 2019;8:313-322. DOI: 10.1302/2046-3758.87.BJR-2018-0271.R1.

Background: The interaction between wrist kinematics and synovial fluid pressure has yet to be studied. To our knowledge, this is the first study to determine the effect of scapholunate joint kinematics on synovial fluid pressure change using finite volume method. Methods: The carpal bones of a cadaveric hand were obtained from Computed Tomography (CT) scans. CT images of the carpal bones were segmented and reconstructed into 3D model. The 3D synovial fluid model between the scaphoid and lunate was constructed and then used for computational simulations. The kinematics data of scapholunate joint obtained from radioulnar deviation of the wrist was investigated. Results: It was found that the pressure in synovial fluid varied from -1.68 to 2.64 Pa with maximum pressure located at the scaphoid-fluid interface during the radial deviation. For ulnar deviation, the pressure increased gradually from the scaphoid-fluid interface towards the lunate-fluid interface (-1.37 to 0.37 Pa). Conclusions: This new computational model provides a basis for the study of pathomechanics of ligament injury with the inclusion of synovial fluid.

Background: Crush injury of nerves is a common condition but the biomechanical integrity of the human peripheral nerve after crushing is unknown. This study aims to investigate the impact of crush injury on human digital nerves based on different compressive forces., Materials and Methods: Twenty digital nerves were harvested from three fresh-frozen cadaver hands. The original diameters of proximal, middle and distal end of nerve segment were measured. The midst of each digital nerve was compressed by a customized mechanical system, at 1N, 3N and 5N for 30sec. The diameters were measured again within 1 minute after the nerve crush test was performed. The digital nerve was then subjected to biomechanical test to measure its ultimate tensile strength, stiffness, maximum stress and strain. Deformity of digital nerve was computed based on the diameter of middle nerve segment before and after crush test., Results: No significant difference was found in between groups for ultimate tensile strength ( p =0.598), stiffness ( p =0.593), maximum stress ( p =0.7) and strain ( p =0.666). The deformity of nerves under the compression of 1N, 3N and 5N was computed at 72.1%, 54.2% and 45.9%. The effect of compression on the deformity of nerves was statistically significant ( p <0.001)., Conclusions: It was found that the compressive forces have no impact on the biomechanical integrity of peripheral nerves but the deformity of nerves could be severely caused by low compressive force. It is suggested that the management of nerve crush injury shall be taken immediately and focus on neurophysiological function and degeneration of nerves for a crush with low compressive force and short duration.

Forceps are essential tools for digital nerve manipulation during digital nerve repair surgery. However, surgeons have to operate forceps with extreme caution to prevent detrimental post-operative complications caused by over-gripping force. Their intrinsically safe characteristics have led to the increasing adoption of soft robotics in various biomedical applications. In this paper, a miniaturized hybrid soft surgical gripper is proposed for safe nerve manipulation in digital nerve repair surgery. This new surgical gripper includes a soft inflatable actuator and a gripper shell with a hook-shaped structure. The ability to achieve a compliant grip and safe interaction with digital nerves is provided by the inflated soft pneumatic actuator, while the rigid hook retractor still allows surgeons to scoop up the nerve from its surrounding tissues during surgery. The performance of the proposed surgical gripper was evaluated by the contact/pulling force sensing experiments and deformation measurement experiments. In the cadaver experiments, this new surgical gripper was able to complete the required nerve manipulation within the limited working space. The average deformation of the digital nerve with an average diameter of 1.45 mm gripped by the proposed surgical gripper is less than 0.22 mm. The average deformity is less than 15% of its original diameter.

Background: Cyclic testing of flexor tendons aims to simulate post-operative rehabilitation and is more rigorous than static testing. However, there are many different protocols, making comparisons difficult. We reviewed these protocols and suggested two protocols that simulate passive and active mobilization., Methods: Literature search was performed to look for cyclic testing protocols used to evaluate flexor tendon repairs. Preload, cyclic load, number of cycles, frequency and displacement rate were categorised., Findings: Thirty-five studies with 42 different protocols were included. Thirty-one protocols were single-staged, while 11 protocols were multiple-staged. Twenty-nine out of 42 protocols used preload, ranging from 0.2 to 5 N. Preload of 2 N was used in most protocols. The cyclic load that was most commonly used was between 11 and 20 N. Cyclic load with increment of 10 N after each stage was used in multiple-staged protocols. The most commonly used number of cycles was between 100 and 1000. Most protocols used a frequency of <1 Hz and displacement rate between 0 and 20 mm/min., Interpretation: We propose two single-staged protocols as examples. Protocol 1: cyclic load of 15 N to simulate passive mobilization with preload of 2 N and 2000 cycles at frequency of 0.2 Hz.; Protocol 2: cyclic load of 38 N to simulate active mobilization, with the same preload, number of cycles, and frequency as above. This review consolidates the current understanding of cyclic testing and may help clinicians and investigators improve the design of flexor tendon repairs, allow for comparisons of different repairs using the same protocol, and evaluate flexor tendon repairs more rigorously before clinical applications., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: When primary repair of transected peripheral nerves is not possible due to large gaps, nerve grafts or repair using conduits are other options to bridge the gap such that the nerve is repaired without tension. When nerve gaps are repaired primarily, there is a worry about tension, failure, and poor healing. In this biomechanical study comparing nerves repaired primarily versus those repaired with conduits, we hypothesized that conduit repair provided greater mechanical breaking strength., Methods: We dissected fresh cadaveric sheep hooves and transacted their peripheral nerves. Subsequently, we divided these transacted nerves into 2 groups: primary repair versus repair using a nerve conduit. After repair using a standardized technique, we tensioned each of these repairs via a load tester and recorded the force required till repair failure occurred., Results: Six nerves using primary nerve repair and 6 nerves repaired with a nerve conduit (10 mm length × 2.5 mm diameter) were studied. The average breaking strength of the nerves repaired with the nerve conduit was 0.92 N and that using the primary nerve repair technique was 0.46 N ( P = 0.001). All the nerves repaired using nerve conduit repair had an additional 5 mm added to their total length as compared with the nerves in the other group., Conclusions: Nerve repair using a nerve conduit ensures a higher breaking strength and potentially a greater tension-free repair as compared with primary nerve repairs in a sheep model. This study supports the use of conduits in the bridging of nerve gaps.

Background: This study evaluated the feasibility of using a low-profile titanium (Ti) plate implant, also known as the Ti-button, for Zone II flexor tendon repair. We hypothesize that the use of the Ti-button can distribute the tensile force on the digital flexor tendons to achieve better biomechanical performance., Methods: Twenty lacerated porcine flexor tendons were randomly divided into two groups and repaired using Ti-button or 6-strand modified Lim-Tsai technique. Ultimate tensile strength, load to 2 mm gap force, and mode of failure were recorded during a single cycle loading test. We also harvested twelve fingers with lacerated flexor digitorum profundus tendons from six fresh-frozen cadaver hands and repaired the tendons using either Ti-button method or modified Lim-Tsai technique. A custom-made bio-friction measurement jig was used to measure the gliding resistance and coefficient of friction of the tendon sheath interface at the A2 pulley., Results: The ultimate tensile strength, load to 2 mm gap force, stiffness, and gliding resistance of the Ti-button repairs were 101.5 N, 25.7 N, 7.8 N/mm, and 2.2 N respectively. Ti-button repairs had significantly higher ultimate tensile strength and stiffness than the modified Lim-Tsai repair. However, Ti-button also increased the gliding resistance and coefficient of friction but there was no significant difference between the two repair techniques., Conclusions: Ti-button repair displayed comparable mechanical properties to the traditional repair in terms of 2-mm gap formation and gliding resistance, but with a stronger repair construct. Thus, this deepened our interest to further investigate the potential of using Ti-button implant in Zone II flexor tendon repair by studying both the mechanical and biochemical (tendon healing) properties in more in-depth.

We compared the Lim/Tsai tendon repair technique using an extra-tendinous knot with modification using an intra-tendinous knot. The ultimate tensile strength, load to 2 mm gap force, stiffness, mode of failure, location of failure, and time taken to repair each tendon were recorded during a single cycle loading test in 20 tendons with each repair method. We found that the ultimate tensile strength and 2 mm gap force of the modified Lim/Tsai repair with an extra-tendinous knot (56 SD 5 N and 14 SD 2 N, respectively) were statistically significantly higher than that of the modified Lim/Tsai repair with intra-tendinous knot (51 SD 7 N and 11 SD 2 N, respectively). We conclude that the modified Lim/Tsai repair with extra-tendinous knot is stronger, despite having the same number of core strands.

This study compared the biomechanical performance of a novel 6-strand asymmetric flexor tendon repair with the modified Lim-Tsai technique using cyclic testing. Two groups of ten porcine tendons each were repaired and tested. Gap formation at every 100 cycles was measured. Survival was defined as maximum gap formation below 2 mm. All the repairs survived Stage I. With increased cyclic load in Stage II, the mean gap formation of modified Lim-Tsai repairs exceeded 2 mm at the 600th cycle and reached 4.2 mm (SD 1.93) at the end of Stage II, resulting in 0% survival. The mean gap formation of asymmetric repairs reached 2.0 mm (SD 1.43) at the 800th cycle and was 2.4 mm (SD 1.52) at the end of Stage II, with 60% survival. The asymmetric repair has better biomechanical performance under cyclic testing as compared with the modified Lim-Tsai repair.

Background: To propose a new term ('construct efficiency') for the evaluation of multi strands flexor tendon repairs using different suture materials., Methods: A total of twenty specimens from 4-0 braided polyblend sutures (FiberLoop/FiberWire; Arthrex, Naples, FL) and 4-0 nylon sutures (Supramid Extra II; S. Jackson, Inc., Alexandria, VA) were subjected to tensile testing using Pneumatic Cord-and-Yarn Grips (Instron Corp., Canton MA, USA). The ultimate tensile strengths of the suture materials were measured. The expected repair strengths and construct efficiencies were computed based on the experimental results and from available literature on actual repair strengths of the 4-strand Becker, Cruciate repairs and 6-strand Tang, modified Lim-Tsai repairs., Results: The ultimate tensile strength of nylon suture was 15.4 ± 0.6N, lower than that of braided polyblend suture (45.3 ± 2.3N) with a difference of 194%. The construct efficiency of multi strand repairs varied with respect to different repair techniques and suture materials. It was found that the Becker repairs using FiberWire had the highest construct efficiency (55.7%) followed by the modified Lim-Tsai using Supramid (50.9%), Tang repair using Supramid (49.8%), Cruciate repair using Fiberwire (49.1%), and modified Lim-Tsai repair using FiberLoop (33.5%)., Conclusions: The construct efficiency is more accurate in showing that, in terms of biomechanical strength, the use of FiberWire for the 4-strand Becker and Cruciate repair is more efficient than that of using FiberLoop for 6-strand modified Lim-Tsai repair.

Purpose: In this study, we compared the Tang repair technique with the 6-strand modified Lim-Tsai repair technique under cyclic testing conditions., Methods: Twenty fresh-frozen porcine flexor tendons were randomized into 2 groups for repair with either the modified Lim-Tsai or the Tang technique using Supramid 4-0 core sutures and Ethilon 6-0 epitendinous running suture. The repaired tendons were subjected to 2 stage cyclic loading. The survival rate and gap formation at the repair site were recorded., Results: Tendons repaired by the Tang technique achieved an 80% survival rate. None of the modified Lim-Tsai repairs survived. The mean gap formed at the end of 1000 cycles was 1.09 mm in the Tang repairs compared with 4.15 mm in the modified Lim-Tsai repairs., Conclusions: The Tang repair is biomechanically stronger than the modified Lim-Tsai repair under cyclic loading., Clinical Relevance: The Tang repair technique may exhibit a higher tolerance for active mobilization after surgery with less propensity for gap formation., (Copyright © 2018 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Background: This study evaluated the biomechanical performance of a novel asymmetric 6-strand flexor tendon repair technique without locking loops., Methods: Twenty porcine flexor tendons were equally repaired by using the asymmetric technique and compared with the modified Lim-Tsai repair technique. The ultimate tensile strength, load to 1-mm gap force, stiffness, and mechanism of failure were measured., Results: The asymmetric repair technique had significantly higher tensile strength (63.3 ± 3.7 N) than the modified Lim-Tsai repairs (46.7 ± 8.3 N)., Conclusions: A novel flexor tendon repair technique with improved biomechanical performance may be available for use in flexor tendon repairs.

The Lim/Tsai tendon repair technique has been modified clinically to achieve a 6-strand repair using a single looped suture with one extratendinous knot. We compared biomechanical performance of the original and modified methods using 20 porcine flexor digitorum profundus tendons. The ultimate tensile strength, load to 2 mm gap force, mode of failure, and time taken to repair each tendon were recorded during a single cycle loading test in 10 tendons with each repair method. We found that despite having the same number of core strands, the single looped suture modified Lim/Tsai technique possessed significantly greater ultimate tensile strength and load to 2 mm gap force. Also, less repair time was required. We conclude that the modified 6-strand repair using a single looped suture has better mechanical performance than the original method. The difference likely was due to the changes in locations of the knots and subsequent load distribution during tendon loading.

Purpose: To determine the effects of the Ziemer LDV Z8 liquid interface femtosecond laser platform during capsulotomy under different energy settings in the presence of corneal edema., Methods: Cadaveric porcine eyes (n = 36) employed at less than 6 and greater than 24 post enucleation hours to simulate clear/edematous corneas, underwent capsulotomy with the Ziemer LDV Z8 femtosecond laser (5-mm diameter, energy 90%, 130%, or 150%). Lens capsules were removed for evaluation by scanning electron microscopy and rupture strengths determined by the single column universal testing system. Following ethical approval, 23 patients had lens capsules removed during routine cataract surgery following manual or Z8 capsulotomy and subjected to TUNEL assay., Results: There was no difference in edge morphology or rupture strength (120, 113, and 118 mN at increasing energy, P = 0.42) in the clear cornea. Only 50% of capsulotomies succeeded at 90% energy in an edematous cornea, improving with increased energy (75% completion at 130%, 100% at 150%). Rupture strength in edematous corneas was not significantly different at 112, 133, and 114 mN for 90%, 130%, and 150%, respectively (P = 0.3). In human samples, increased TUNEL-positive cells were seen at 130% energy, but not at 150% (0.0 manual vs. 0.2 [90%] vs. 2.1 [130%] vs. 0.6 [150%], P < 0.05)., Conclusions: Because of the low energy delivered by a femtosecond nanojoule platform, even incremental increases in energy appeared to have minimal effect on lens capsule morphology and strength and negligible influence on cell death. Furthermore, increasing energy appeared to enhance consistency and the ability to complete a capsulotomy in an edematous cornea.

We hypothesized that, in providing biomechanical strength, at least one of the two middle strands in a modified six-strand Lim-Tsai flexor tendon repair could be divided without obvious reduction in repair strength owing to uneven load bearing. A total of 40 porcine flexor digitorum profundus tendons were repaired using the six-strand Lim-Tsai technique with a 4-0 FiberLoop ® suture and then divided into four equal groups. (no cut, one middle strand cut, both middle strand cut, one side strand cut). The biomechanical performance of repaired tendons was tested and found to vary according to the location of the cuts.

The introduction of femtosecond laser assisted cataract surgery (FLACS) is a paradigm changing approach in cataract surgery, the most commonly performed surgical procedure. FLACS has the potential to optimize the creation of an anterior lens capsulotomy, a critical step in accessing the cataractous lens. The merits of using a laser instead of a manual approach include a potentially more circular, consistent, and stronger aperture. In this study we demonstrated for the first time in both a porcine and human experimental setting that with a low energy, high repetition FLACS system, that a circular, smooth and strong capsulotomy was achievable. While there was no demonstrable difference in the resistance to rupture before or after the removal of the nucleus, larger capsulotomies had an increase in tensile strength. The LDV Z8 system appeared to create circular, rupture-resistant and smooth capsulotomies in both porcine and more importantly human globes.