Mesh Type Research Articles

Ratcheting Simulation of Additively Manufactured Aluminum 4043 Samples through Finite Element Analysis

This study presents a finite element-based ratcheting assessment of additively manufactured aluminum 4043 samples undergoing asymmetric loading cycles. The Chaboche material model in ANSYS was utilized and the effects of mesh and element type were examined. Different element numbers were used in a thorough convergence study to obtain independent meshing structures. The coefficients of this model were defined through stress–strain hysteresis loops determined from the strain-controlled tests. The backstress evolution and the corresponding yield surface translation in the deviatoric stress space were discussed as three different mesh elements of linear brick, quadratic tetrahedron, and quadratic brick were adopted. The magnitude of backstress was affected as different element types were employed. The first-order brick elements resulted in the highest backstress increments, while the lowest backstresses were determined when quadratic brick elements were taken. Backstress increments are positioned in an intermediate level with the use of quadratic tetrahedron elements. The choice of the element type, shape, and number influenced material ratcheting response over the loading process. The use of quadratic brick elements elevated the simulated ratcheting curves. The quadratic tetrahedron and linear brick elements, however, suppressed ratcheting level as compared with those of experimental data. The closeness of the simulated ratcheting results to those of the measured values was found to be highly dependent on these finite element variables.

Performance of wildlife fence systems under animal impact load

Wildlife fence protection systems specifically designed for animal protection are critical in mitigating wildlife-vehicle collisions and preserving animal habitats. These systems are quite similar to rockfall barrier systems, which are well studied and developed, however, few studies are specifically oriented toward investigating structural performance of these systems. Despite the similarities, results of studies related to rockfall barriers may not be directly applicable to design and performance evaluation of wildlife barrier systems due to differences in a range of size, shape, and velocity of impactors and structural details. This study aims to bridge this gap by analyzing performance and capacity of wildlife structures in more detail through parametric study with consideration of a wide range of properties and structural details appropriate for these systems, such as mesh type (square and inclined), mesh size, and wire diameters. The behavior of these systems under impact loads is simulated using nonlinear finite element models with consideration of ductile damage and element removal techniques to accurately capture wire rupture and changes in the impactor-fence system interface. The results demonstrate that the response of the system is highly influenced by factors such as mesh type, opening size, wire diameter, and impactor size. Notably, the system utilizing an inclined mesh type exhibits a 35 % higher failure velocity, 50 % greater energy dissipation, and 21 % less maximum displacement compared to the square mesh system. The detailed results and discussions in this study provide valuable insights into the influence of individual parameters on the behavior of wildlife fence systems, aiding in the design of more efficient wildlife barrier systems with enhanced performance.

A preliminary In Vitro viability study of an electrically active hernia mesh on mouse fibroblasts.

Hernias occur when part of an organ, typically the intestines, protrudes through a disruption of the fascia in the abdominal wall, leading to patient pain, discomfort, and surgical intervention. Over one million hernia repair surgeries occur annually in the USA, but globally, hernia surgeries can exceed 20 million. Standard practice includes hernia repair mesh to help hold the compromised tissue together, depending on where the fascial disruption is located and the patient's condition. However, the recurrence rate for hernias after using the most common type of hernia mesh, synthetic, is currently high. Physiological-level electrical stimulation (ES) has shown beneficial effects in improving healing in soft tissue regeneration. Piezoelectric materials can produce low-level electrical signals from mechanical loading to help speed healing. Combining the novelty of piezo elements to create an electrically active hernia repair mesh for faster healing prospects is explored in this study through simulated transcutaneous mechanical loading of the piezo element with therapeutic ultrasound. A tissue phantom was developed using Gelatin #0 and Metamucil® to better simulate a clinical application of the therapeutic ultrasound loading modality. The cellular viability of varying ultrasound intensities and temporal effects was analyzed. Overall, minimal cytotoxicity was observed across all experimental groups during the ultrasound intensity and temporal viability studies.

The Effect of Mesh Fixation Methods on Pain Sensation After Laparoscopic Inguinal Hernia Repair

Aim: Groin hernia repair is one of the most common surgical procedure in general surgery. The use of prosthetic meshs has reduced the recurrence rate after inguinal hernia repair to less than 5%. Chronic pain is thought to be multi-factorial. Among these, surgical-related factors are the types of mesh used and fixation methods. It was aimed to evaluate the effect of the use of absorbable and non-absorbable screws for mesh fixation on post-operative pain during TEP repair.
 Material and Methods: The data of patients who were operated on by a single surgeon and who underwent TEP repair for unilateral or bilateral inguinal hernia were reviewed retrospectively. Post-operative first-week pain sensations were compared between patient groups in which absorbable and non-absorbable screws were used for patch fixation.
 Results: A total of 35 patients who were operated by a single surgeon and who underwent laparoscopic total extraperitoneal (TEP) repair for unilateral or bilateral inguinal hernia were included in the study. It was found that patients in the absorbable screw group felt statistically significantly less pain [VAS: 3 (2-7) vs. 4 (2-8); p=0.03].
 Conclusion: Chronic pain after patchy hernia repair is also seen as a late complication that can last up to 6 months. This study, which proves that the use of absorbable stabilizers leads to less pain in the early period, reveals that this method may also be a suitable method for preventing the development of possible chronic pain.

Indocyanine Green Fluorescent Lymphography During Open Inguinal Hernia Repair: Relationship Between Lymphatic Vessel Injury and Postoperative Hydrocele.

This prospective case series analyzed patients who underwent indocyanine green (ICG) fluorescent lymphography during open inguinal hernia repair. The aim of this study was to investigate the association between ICG leakage and postoperative hydroceles in patients who underwent inguinal hernia repair. Data were analyzed from 40 patients who underwent primary open hernia repair between October 2020 and June 2021 (44 cases in total). Hydroceles were categorized into two types: symptomatic and "ultrasonic" (detected only by ultrasound imaging). In the univariate analysis, hernia type (p = 0.044) and ICG leakage (p = 0.007) were independent risk factors for postoperative ultrasonic hydroceles. Additionally, mesh type (p = 0.043) and ICG leakage (p = 0.025) were independent risk factors for postoperative symptomatic hydroceles. In the multivariate analysis, ICG leakage (p = 0.034) was an independent risk factor for postoperative ultrasonic hydroceles. ICG leakage after inguinal hernia repair was independently associated with postoperative ultrasonic and symptomatic hydroceles. These findings suggest a relationship between lymphatic vessel injury and the incidence of postoperative hydroceles.

Management of incisional hernias in renal transplant patients

BackgroundIncisional hernia (IH) remains one of the most common complications following abdominal organ transplantation with no consensus on the optimal management. This study is a narrative review of the incidence, risk factors, diagnosis, and management of IH post-transplantation. MethodsA literature search using the EMBASE and MEDLINE from 1.1.2016 to 15.8.2002 was conducted. Included studies reported on IH after open abdominal organ transplantation. The outcomes included in our analysis were the incidence of IH, significant patient risk factors, the diagnostic approach used to detect IH, and proposed strategies for the management of IH. 54 publications that involved 9336 transplant patients who developed IH were included. ResultsThe incidence of IH ranged from 1.7 % to 43 % in liver transplant patients and was lower following kidney transplantation (1.1 %-7.0 %). Patient risk factors predisposing to IH were body mass index>30, age (>50), smoking history, previous open abdominal surgery, open surgical repair, a Mercedes or inverse T incision and surgical site infections. The most common diagnostic approach for IH is clinical examination, followed by US or CT imaging in cases of complex IH. Following IH repair, recurrence rates ranged from 0 to 76.9 %, and complication rates from 12 % - 52.9 %, the most common of which were surgical site occurrences (11.0–79.2 %) including infection (0 - 65.4 %) and seroma formation (0–8 %). Management of IH should include preoperative optimisation of patients through weight reduction, smoking cessation and adjustment of immunosuppression using a multidisciplinary (MDT) approach. Mesh repair, either open or laparoscopic, is the gold standard for the treatment of IH, resulting in a significantly lower recurrence rate than primary closure. There is no consensus on the type and positioning of mesh, and very limited studies have reported on other perioperative factors such as wound closure. ConclusionsPrehabilitation and MDT approach are important in ensuring good outcomes following IH repair. Further prospective studies and the establishment of a relevant registry are required to propose a consensus pathway for IH repair in the transplanted population.

Immediate breast reconstruction in breast cancer patients with the use of Serasynth and SeragynBR synthetic meshes. Single-oncological center experience, analysis of complications.

<br><b>Introduction:</b> The use of meshes in mastectomies with immediate breast reconstruction (IBR) has become the gold standard.</br> <br><b>Aim:</b> The use of meshes in mastectomies with immediate breast reconstruction (IBR) has become a gold standard. The purpose of the study was to analyze the complications and own experience with the use of Serasynth fully absorbable and SeragynBR partially absorbable synthetic meshes.</br> <br><b>Material and methods:</b> In the period from December 2017 to July 2020, 118 IBR were performed in the Author's Department with the use of SeragynBR and Serasynth meshes in 93 patients operated for breast cancer. 78 Serasynth meshes (Group 1) and 40 SeragynBR meshes (Group 2) were implanted.</br> <br><b>Results:</b> The most common complication was persistent seroma collection, which was reported in 17.9% of cases in Group 1 and 25% in Group 2. Skin inflammation was reported in 7.6% and 17.5%, while infections in 2.5% and 5% of the operated breasts in Group 1 and Group 2. Reoperation was required in 5.1% and 5% of the patients in Group 1 and Group 2. The percentage of complications was lower when Serasynth rather than Seragyn BR meshes were implanted. The frequent incidence of the seroma collection did not contribute in any significant way to serious complications such as removal of mesh/implant or infection. The complications, which developed following the implantation of both mesh types, were similar to those presented in other publications concerning mastectomy with IBR with the use of synthetic meshes. The percentage of implant losses/explanations in the discussed groups was lower than that reported in the literature.</br> <br><b>Conclusion:</b> Despite the complications, both types of meshes can be considered as safe additions to reconstructive breast surgeries.</br> <br><b>Level of Evidence:</b> Level III.</br&gt.

Does the Weight Matter? Short-Term Outcomes of Lightweight Versus Heavyweight Three-Dimensional Anatomical Mesh in Minimally Invasive Inguinal Hernia Repair.

Background: The type of mesh used in inguinal hernia repairs remains controversial. There are limited data looking at specific mesh-related complications. The objective of this study is to assess postoperative 90-day outcomes in lightweight (LW) and heavyweight (HW) anatomical mesh in minimally invasive inguinal hernia repairs. Methods: A retrospective single-center database was queried for all adult minimally invasive inguinal hernia repairs with anatomical mesh from July 2016 to March 2021. Demographics and surgical outcomes were analyzed. Univariate analysis and multivariate logistic regression were performed. Results: Six hundred forty-seven minimally invasive inguinal hernia repairs were performed with 423 (65.3%) using HW and 224 (24.7%) using LW mesh. There was no difference in mean body mass index between the groups (26.9 ± 4.2 kg/m2 in the LW group and 27.1 ± 4.2 kg/m2 in the HW group; P = .69). There was no difference in type of mesh fixation used in either group, with tacker being the most common. There was no difference in postoperative emergency department (ED) visit (P = .625), readmission rates (P = .562), or postoperative complications between the two groups. Fifty patients presented with seroma within 90 days. There were five recurrences in each group and only one surgical site infection in the LW within 90 days. Multivariate logistic regression was performed, and predictors of seroma formation included age (odds ratio [OR] 1.02; confidence interval [CI] 1-1.04; P = .02) and hypertension (HTN) (OR 1.8; CI 1.03-3.4; P = .039). HW mesh was not associated with seroma formation (OR 1.04; CI 0.5-1.9; P = .895). Similarly, HW mesh was not associated with surgical site occurrences (SSO) (OR 1.04; CI 0.5-1.8; P = .872). HTN was associated with SSO (OR 1.74; CI 1-3.05; P = .048). Conclusion: Our study did not favor the use of LW or HW mesh when comparing postoperative complications or clinical outcomes. HW mesh was not associated with either seroma formation or SSO.

Mesh optimization using an improved self-organizing mechanism

As more powerful computing hardware enables higher resolution simulations, a fast and flexible mesh optimization method is becoming increasingly indispensable for Computational Fluid Dynamics (CFD), which unfortunately remains a bottleneck in the current CFD workflows. In this paper, a novel mesh optimization method based on an improved self-organizing map (SOM) neural network is proposed to improve the accuracy and efficiency of numerical simulation while maintaining constant computational cost. During an improved competitive learning procedure in SOM, the node distribution with constant connectivity rapidly matches the characteristics of the flow field, which is predicted by a Multilayer Perceptron (MLP). Based on the local element volume and flow solution variations, annealing schemes for self-adaptation of important SOM parameters are designed to ensure the convergence of the proposed algorithm. Specially, a feasible region constraint and a smoothing constraint are embedded into the node movement to avoid mesh tangling and excessive mesh skewness, and make the transition between nodes gradual. The proposed approach is applicable to various types of meshes and is easy to implement without code intrusiveness. Comparative results on benchmark examples and typical CFD examples demonstrate that the proposed method attributes to both the improvement in the computational accuracy and efficiency. It exhibits the potential to be a flexible and promising tool for rapid mesh optimization in CFD and other engineering fields.

Axial load behavior of unreinforced and reinforced hollow interlocking compressed stabilized earth block masonry walls

This study investigates the axial load behavior of unreinforced and reinforced hollow interlocking compressed stabilized earth block masonry walls. Sixty walls were constructed and tested under axial compression. The variables include block type (unreinforced and coir fibre reinforced), grout condition (ungrouted and grouted), channel blocks, reinforcement type (steel bars and bamboo splints) and configuration (vertical and mesh type). The results show that addition of coir fibres significantly increase the axial load capacity and ductility of walls, regardless of all other variables considered. Grouting of masonry cores increases the load capacity of unreinforced and fibre-reinforced walls (without bamboo/steel reinforcement), however slightly affecting the deflection capacity. The channel block had a detrimental effect on the load and deflection capacity of both unreinforced and reinforced walls. Bamboo/steel reinforced vertically significantly contributed to the axial load and deformability of walls, despite the presence or absence of channel blocks. Both bamboo and steel reinforced walls behaved in a similar manner; yet bamboo splints showing slightly lesser load and deflection capacity than steel. The axial load and deflection capacity of bamboo reinforced grouted walls are about 78.54% to 90.00% and 79.50% to 94.60% respectively as compared to steel reinforced counterparts. Bamboo/steel mesh reinforced walls with channel blocks exhibited better performance compared to corresponding specimens with only vertical reinforcement. However, the improvement was marginal, due to larger spacing between the horizontal reinforcement. Nevertheless, the presence of horizontal reinforcement greatly improved the failure behavior by restraining the buckling of vertical reinforcement. Overall, fibre and vertical steel reinforced grouted wall specimens without channel blocks (FSVRGMW) showed the best performance in terms of compressive strength. The design equations in MSJC-11 predicted the load capacity of unreinforced and reinforced masonry walls more conservatively. Finally, it can be stated that MSJC-11 recommendation of internally reinforced grouted walls must be treated as unreinforced walls, if no horizontal reinforcements was provided, is not reasonable.

Flexural behavior of reinforced concrete beams strengthened using recycled industrial steel-wire mesh high-performance mortar

Industrial recycled steel wires extracted from waste tires can be combined with high-performance mortar by weaving them into a mesh to apply this type of strengthening method, which exhibits high tensile strength, high toughness, and excellent cracking resistance in building structures. This paper presents a flexural behavior study of reinforced concrete (RC) beams under different industrial recycled steel wire working conditions. We examined the resultant steel-wire mesh high-performance mortar, investigating the stiffness, ductility, and load carrying capacity of the experimental beams under different anchorage measures using different mesh types and sizes. The results showed that both the weaving of the recycled industrial steel wire into a mesh and the rebar-planting anchorage measures were effective in preventing the stripping of the strengthening layers, allowing the tensile performance of the recycled industrial steel wire to be fully utilized and the ultimate load capacity of the RC beams to be considerably increased. At the same time, the industrial recycled steel-wire mesh also played an important role in the inhibition of crack development, with the width of the cracks in the strengthening beams decreasing and an overall appearance of "fine and dense" character. As the volume of steel bars in industrial recycled steel-wire mesh increases, the ultimate bearing capacity and stiffness of the beam increased. To verify the strengthening effect of industrial recycled steel-wire mesh high-performance mortar on the beams from multiple angles, this study used finite element analysis software to conduct numerical simulation analyses on four of the experimental beams. The damage cloud charts of the specimens from the numerical simulations were compared with experimental failure phenomena, the deviations between the simulated and experimental values of the specimens being within 10%—that is, the simulation results were in good agreement with the experimental results. The use of industrial recycled steel-wire mesh high-performance mortar strengthening could be applied in actual projects, its green low-carbon credentials achieving the purpose of solid-waste utilization as well as providing strong support for China's early realization of carbon neutrality and related strategic objectives. At the same time, the recycling of waste tires could provide a new research direction.

Evaluating mesh use for abdominal donor site closure after deep inferior epigastric perforator flap breast reconstruction: A systematic review and meta-analysis.

Despite improvement in abdominal morbidity with deep inferior epigastric perforator (DIEP) flap breast reconstruction compared to prior abdominally-based free flap breast reconstruction, abdominal bulge, and hernia rates have been cited anywhere from 2% to 33%. As a result, some surgeons utilize mesh or other reinforcement upon donor-site closure, but its benefit in preventing abdominal wall morbidity has not been well-defined for DIEP flaps. The purpose of this systematic review is to evaluate DIEP donor-site closure techniques and the impact of mesh type and plane on abdominal-wall morbidity including hernia and bulge, relative to primary fascial closure. MEDLINE, PubMED, Cochrane Library, and SCOPUS were systematically reviewed for studies evaluating DIEP flap breast reconstruction abdominal-donor site closure, where any mesh reinforcement or primary fascial closure was specified, and postoperative outcomes of hernia and/or abdominal bulge were reported. Analysis was performed in Review Manager (RevMan) evaluating mesh use, type, and plane relative to primary fascial closure, using the Mantel-Haenszel method to calculate odds ratios (ORs) of significance level p < .05, and a random effects model to account for inter-study heterogeneity. Of the 2791 DIEP patients across 11 studies, 1901 patients underwent primary closure and 890 were repaired with mesh. When hernia and/or bulge were combined into a single complication, the use of any mesh did not significantly reduce its odds compared to primary closure (OR = 0.69, p = .20). Similarly, the use of any mesh did not significantly reduce the odds of bulge alone compared to primary closure (OR = 0.62, p = .43). However, the odds of hernia alone were significantly reduced by 72% with any mesh use (OR = 0.28, p = .03). Mesh use was significantly associated with decreased odds of hernia alone with DIEP flap surgery, but there was no difference in bulge or combined hernia/bulge rates. As bulge is the more common abdominal morbidity after DIEP flap harvest in a patient with no prior abdominal surgery or risk factor for hernia, mesh use is not indicated in abdominal closure of all DIEP patients. Future prospective studies are warranted to characterize the specific indications for mesh use in the setting of DIEP flap surgery.

Mesh overlap for ventral hernia repair in current practice.

Sufficient overlap of mesh beyond the borders of a ventral hernia helps prevent hernia recurrence. Guidelines from the European Hernia Society and American Hernia Society recommend ≥ 2cm overlap for open repair of < 1-cm hernias, ≥ 3-cm overlap for open repair of 1-4-cm hernias, ≥ 5-cm overlap for open repair of > 4-cm hernias, and ≥ 5-cm overlap for all laparoscopic ventral hernia repairs. We evaluated whether current practice reflects this guidance. We used the Michigan Surgical Quality Collaborative Hernia Registry to evaluate patients who underwent elective ventral and umbilical hernia repair between 2020 and 2022. Mesh overlap was calculated as [(width of mesh-width of hernia)/2]. The main outcome was "sufficient overlap," defined based on published EHS and AHS guidelines. Explanatory variables included patient, operative, and hernia characteristics. The main analysis was a multivariable logistic regression to evaluate the association between explanatory variables and sufficient mesh overlap. 4178 patients underwent ventral hernia repair with a mean age of 55.2 (13.9) years, 1739 (41.6%) females, mean body mass index (BMI) of 33.1 (7.2) kg/m2, and mean hernia width of 3.7 (3.4) cm. Mean mesh overlap was 3.7 (2.5) cm and ranged from -5.5 to 21.4cm. Only 1074 (25.7%) ventral hernia repairs had sufficient mesh overlap according to published guidelines. Operative factors associated with increased odds of sufficient overlap included myofascial release (adjusted odds ratio [aOR] 5.35 [95% CI 4.07-7.03]), minimally invasive approach (aOR 1.86 [95% CI 1.60-2.17]), and onlay mesh location (aOR 1.31 [95% CI 1.07-1.59]). Patient factors associated with increased odds of sufficient overlap included prior hernia repair (aOR 1.59 [95% CI 1.32-1.92]). Although sufficient mesh overlap is recommended to prevent ventral hernia recurrence, only a quarter of ventral hernia repairs in a state-wide cohort of patients had sufficient overlap according to evidence-based guidelines. Factors strongly associated with sufficient overlap included myofascial release, mesh type, and laparoscopic repair.

Slowly absorbable mesh in sublay ventral hernia repair in contaminated fields.

In the past years, there has been increasing evidence that supports the use of permanent mesh in contaminated wounds. Given this increased evidence, the indications to opt for slowly absorbable "biosynthetic" prostheses have been questioned. To address this, we compared the outcomes of slowly absorbable mesh in contaminated cases in a well-matched multicentric cohort. The Abdominal Core Health Quality Collaborative (ACHQC) database was queried for patients undergoing elective ventral hernia repair in Centers for Disease Control (CDC)-III operations (2013-2022). We compared demographics, hernia characteristics, and postoperative outcomes among types of mesh. We used propensity score matching to adjust for sex, diabetes, body mass index, smoking status, and operative time between mesh groups. Patients within other CDC classes and those with mesh positioned elsewhere than retro-rectus/preperitoneal space were excluded. A total of 760 patients were included in the analysis. Slowly absorbable synthetic mesh (SA) was utilized in only 7% of the cases, while permanent (P) and biologic (B) mesh in 77% and 16%, respectively. After matching, 255 patients were studied. There was no difference in surgical site occurrence (8% SA, 16% P, 10% B, p = 0.27), surgical site infection (20% SA, 17% P, 12% B p = 0.54), surgical site occurrence requiring intervention (18% SA, 13% P, 14% B p = 0.72), readmission (12% SA, 14% P, 12% B, p = 0.90), or reoperation (8% SA, 2% P, 4% B, p = 0.14) at 30days. In patients with 1-year follow-up, there was no difference in recurrence among groups (20% SA, 26% P, 24% B p = 0.90). Based on our findings, SA has comparable outcomes to other types of mesh, particularly when an optimal retro-rectus repair is performed.

Evaluation of Different Mesh Types of Steel Roof Trusses According to AISC360-16 Code

Evaluation of Different Mesh Types of Steel Roof Trusses According to AISC360-16 Code

Heavyweight versus non-heavyweight mesh in ventral hernia repair: a systematic review and meta-analysis.

There is considerable variability among surgeons regarding the type of mesh used in ventral hernia repair. There has been an increasing incidence of mesh fractures with lightweight (LW) and mediumweight (MW) meshes. However, HW mesh has been associated with a greater foreign body sensation and chronic pain. This meta-analysis aims to compare the outcomes of HW and non-heavyweight (NHW) meshes in ventral hernia repair. We systematically reviewed the PubMed, Embase, Cochrane, and Scopus databases to identify studies comparing HW with NHW meshes in hernia repair. Outcomes analyzed included hernia recurrence, seroma, hematoma, foreign body sensation, postoperative pain, and wound infection. We performed two subgroup analyses focusing on randomized controlled trials and open retromuscular repairs. Statistical analysis was performed using RevMan 5.4. We screened 1704 studies. Nine studies were finally included in this meta-analysis and comprised 3001 patients from 4 RCTs and 5 non-randomized. The majority of patients (57.1%) underwent open retromuscular repair. HW mesh was significantly associated with increased in foreign body sensation (OR 3.71; 95% CI 1.40-9.84; p = 0.008), but there was no difference in other outcomes. In RCTs analysis, there was no difference between meshes. In open retromuscular repairs, HW mesh was associated with more seromas (OR 1.48; 95% CI 1.01-2.17; p = 0.05). Our study found that HW mesh was associated with more foreign body sensation. Also, open retromuscular repairs analysis showed that HW was associated with more seromas. Further randomized studies are needed to understand better the role of HW mesh in ventral hernia repair.

Evaluating uncertainties in CFD simulations of patient-specific aorta models using Grid Convergence Index method

Cardiovascular diseases are among the most important causes of global mortality. Computational Fluid Dynamics (CFD) is a powerful research tool that analyzes the hemodynamics of artery and blood flow patterns. In this study, CFD simulations are performed to assess the patient-specific healthy aorta, fusiform, and saccular aneurysm with various mesh types, including tetrahedral, polyhedral, and poly-hexacore. The aim of this study is to explore how different mesh types and grid densities impact the hemodynamic properties of physiological flows, with the goal of identifying the most cost-effective meshing approach. A mesh independence study is carried out to ensure the precision of the results, considering the wall shear stress distribution. For this, five different mesh resolutions are generated for each geometry. The uncertainties of the simulations associated with the discretization techniques and solutions are evaluated using the Grid Convergence Index (GCI) method. The findings showed that increasing the mesh density provides smaller uncertainty. GCI values for the wall shear stress are in the range of convergence, indicating that the results are reliable and accurate. Mesh type selection affects the accuracy and computational cost of our simulations. The polyhedral and poly-hexacore meshes lead to a good compromise between precision and computational cost, while the tetrahedral mesh style gives the most precise results with fluctuation. This work provides a systematic approach based on the Grid Convergence Index method in order to select the most appropriate mesh type for evaluating uncertainties in CFD simulations of patient-specific healthy aortas and aortas with abdominal aneurysms. According to the findings and GCI analysis, the polyhedral mesh type was chosen for all patient-specific aorta models. The study clearly demonstrated its superiority over other mesh types, considering uncertainties and computational costs associated with different mesh styles.

232 The inGuinal heRnia OperatIon Notes (GROIN) Quality Improvement Project

Abstract Aims Accurate and comprehensive operation notes are crucial for patient safety, quality assurance and medico-legal purposes. Inguinal hernia repair is one of the most common surgical procedures. Thus, operative documentation should be precise and standardised. The GROIN project aims to improve the quality of inguinal hernia operation notes using evidence-based proformas and an operation note composition software. Method We retrospectively reviewed operation notes of inguinal hernia repair performed at our institution between August and November 2022. Operation notes were assessed against the Royal College of Surgeons' Good Surgical Practice standard, consisting of 18 items. Results The operation notes from 89 cases were reviewed. High-scoring items included: operation name (100%), operative findings (99%), surgeon's name (99%), closure technique (98%), operation date (90%) and signature (90%). Postoperative instructions were sufficiently detailed in 79% of cases. Regarding mesh placement, 63% of notes described mesh size and type, whereas 30% documented only the mesh type. The lowest-scoring items were: venous thromboembolism prophylaxis (31%), designation as elective or emergency (22%), operative diagnosis (6%), and estimated blood loss (2%). Conclusions We identified several areas for improvement in inguinal hernia operation notes based on our results. The next step of the GROIN project is to standardise operation note creation by implementing an evidence-based template, which will be delivered through a novel operation note composition software. This will allow accurate record-keeping and efficient operative data extraction analysis. Efforts to standardise operative notes and enhance their quality on a national and international level are imperative for patient safety.

California Sea Cucumber (Apostichopus californicus) Abundance and Movement on a Commercial Shellfish Aquaculture Farm

California sea cucumbers (Apostichopus californicus) are often abundant at oyster farms in British Columbia, Canada both on the suspended gear as juveniles and on the seafloor beneath them as a mixture of juveniles and adults. Their natural abundance, high value, and potential to mitigate benthic organic loading has led to an interest in their coculture with oysters. Whether farmed sea cucumbers ought to be contained to physically separate them from wild stocks is debated. The present three-year field study examined the movement of wild California sea cucumbers on/off an operational oyster farm (~3000 m2) to help inform future sea cucumber aquaculture development. Sea cucumber effects on organic loading, immigration to/emigration from the farm, and the efficacy of various containment-material mesh types and sizes were examined. Juvenile and adult sea cucumber densities on the farm steadily increased from the end of winter through the end of summer, likely due in large part to juveniles falling off the suspended oyster gear, which occurred at an average rate of ~780 ind d−1 (for the whole farm) in the summer months. The largest increase in abundance on the farm was observed between January and March/April, when the population increased by 100–350 ind d−1. Between late summer and early winter, sea cucumbers emigrated from the farm at a rate of 50–90 ind d−1, neither juvenile nor adult densities on the farm changing appreciably over the winter. The sea cucumber density showed a progressive decrease in the first 20 m from the farm, after which the animals were scarcely noticed. Apostichopus californicus did not significantly decrease sediment organics beneath the farm compared to a nearby control site, but such an effect may have been lost due to their seasonal feeding cycles and/or the presence of other benthic grazers that were not part of our exclusion trial. Overall, our findings suggest that the separation of farmed and wild California sea cucumbers on a shellfish farm can only be guaranteed through containment, given the dynamic immigration and emigration patterns of wild stocks. Through laboratory trials, we found that individuals of A. californicus were able to squeeze through mesh as small as 32% of their contracted width and could escape fenced areas (90 ± 4% escape from nylon fencing and 40 ± 8% escape from VexarTM fencing) unless the fencing extended above the water surface (where there was no escape from either type).

Long-Term Outcomes following Hybrid Breast Reconstruction.

Hybrid breast reconstruction combines free tissue transfer with implant placement. Various mesh products have been successfully used to secure the implant position in these reconstructions. In this study, the authors investigate the impact of mesh type on long-term outcomes following hybrid breast reconstruction. A retrospective analysis of all patients with at least 24 months of follow-up after immediate bilateral prepectoral hybrid breast reconstruction was performed. Univariate and multivariable regression analyses were used to evaluate long-term outcomes and compare breasts reconstructed with polyglactin mesh versus acellular dermal matrix (ADM). Thirty-nine patients (78 breasts) who underwent hybrid breast reconstruction with an average follow-up period of 50.4 months (range, 27 to 73 months) were included in the study. Postoperative complications included hematoma ( n = 2 [2.6%]), mastectomy skin necrosis ( n = 12 [15.4%]), and fat necrosis ( n = 6 [7.7%]). There were no instances of implant infection, implant exposure, or flap failure. Polyglactin mesh and ADM were used in 24 breasts and 54 breasts, respectively. Implant malposition and capsular contracture occurred more frequently in the polyglactin cohort leading to 10 (41.7%) instances of reoperation for implant replacement compared with only 1 (1.9%) in the ADM cohort ( P < 0.001). On multivariable regression analysis, polyglactin mesh was associated with a 36-fold greater probability of requiring implant replacement compared with ADM ( P = 0.006). ADM (versus polyglactin mesh) is associated with lower rates of capsular contracture and implant malposition in the context of hybrid breast reconstruction. Therapeutic, III.