Subsequent Mesh Research Articles

EMERGENCY LAPAROSCOPIC TRANSABDOMINAL PREPERITONEAL (TAPP) HERNIOPLASTY FOR GARANGEOT'S HERNIA: A CASE REPORT

Abstract Aims This video presentation aims to demonstrate the successful management of a rare and challenging case of Garangeot's hernia through Emergency Laparoscopic Transabdominal Preperitoneal (TAPP) Hernioplasty. The primary objectives include highlighting the surgical technique, intraoperative findings, and postoperative outcomes in the context of this uncommon hernia presentation. Materials and Methods An 84-year-old female presented to the emergency department with signs of femoral hernia incarceration. Upon exploration, a Garangeot's hernia, characterized by the presence of the appendix within a femoral hernia sac, was identified. In light of the emergency and the patient's deteriorating condition, an Emergency Laparoscopic TAPP Hernioplasty was performed. The procedure involved meticulous dissection of the hernia sac, reduction of the herniated appendix and appendectomy, and subsequent mesh reinforcement of the femoral defect. Results The video illustrates the step-by-step approach to Emergency Laparoscopic TAPP Hernioplasty in the context of Garangeot's hernia. Intraoperative findings, including the condition of the herniated appendix and associated anatomical structures, are presented. Postoperative outcomes, including recovery, complications, and follow-up observations, are discussed to provide a comprehensive understanding of the case. Conclusions Emergency Laparoscopic TAPP Hernioplasty emerges as a viable and effective intervention for Garangeot's hernia, offering advantages such as reduced morbidity, quicker recovery, and minimal surgical trauma. This video contributes valuable insights into the management of this rare hernia presentation, emphasizing the role of minimally invasive techniques in achieving successful outcomes.

Influence of profile modification on the transmission error of spur gears under surface wear

The load distribution, transmission error, and time-varying meshing stiffness of spur gears are all influenced by the teeth dimensions and profiles shape. Any modification on the teeth geometry, as a profile relief frequently used to avoid the mesh-in impact, will affect all these parameters and the entire dynamic behavior of the gearset. In addition, due to the friction between contacting surfaces, wear arises at the teeth flanks. This causes the shape of the meshing profiles to change, which will affect the load distribution and the transmission error for the subsequent meshing cycles. And this new load distribution causes a surfaces wear different form that of the previous meshing cycle. Consequently, the wear depth increase is different at any contact point —because the load and sliding velocity are different— and at any meshing cycle as well —because the load distribution changes with the accumulated wear—. And all the above is also influenced by the profile modification the teeth were manufactured with. In this paper, a simple, analytic model of meshing stiffness, load sharing, and transmission error for spur gears with profile modifications including the influence of surfaces wear is presented. The evolution of the transmission error with the number of wear cycles is studied, and the optimal profile modification for minimizing the dynamic load induced by the transmission error is investigated.

Propagating Design Updates to Structured Analysis Meshes

Generating structured meshes is often an expensive process, limiting the use of high-fidelity numerical simulation methods for design, especially when the design is not yet fixed and design updates are likely. For hexahedral meshes generated by decomposing a B-Rep model into regions for which simple meshing strategies are known, robustly propagating design modifications to the decomposed representation and subsequent mesh is very challenging. In this paper, an approach is presented to propagate parametric update and feature changes to structured meshes. Geometric and topological modifications on the design model are identified first, enabling the equivalent modifications to be identified on the decomposition of the design model. Virtual topology operations used to generate the initial decomposition are combined with the meshing constraints of individual sub-regions to update the decomposition and associated mesh locally. The approach is demonstrated for a number of design updates.

Multidisciplinary Approach to Robotic Resection of Abdominal Wall Endometriosis and Mesh Repair

To demonstrate a technique for robot-assisted laparoscopic excision of abdominal wall endometriosis and mesh reinforcement of the subsequent defect. Description and demonstration of surgical technique. Abdominal wall endometriosis most commonly takes hold after seeding of a previous cesarean scar [1-5]. As of 2018, 31.9% of deliveries in the United States were accomplished by cesarean section [6]. With endometriosis at an estimated incidence of 11% in the United States, evaluation for, and minimally invasive management of, abdominal wall endometriosis is becoming an essential skillset for the gynecologic surgeon [7]. Robot-assisted laparoscopic evaluation of size and location of lesion in relation to anatomic landmarks. Demonstration of techniques to identify borders of endometriotic lesion including clinical and microscopic. Minimally invasive resection of lesion with preservation of vital structures. Placement of abdominal wall mesh for reinforcement of rectus muscle and fascial defect. Peritoneal closure to minimize adhesions and herniation into defect. Brief review of alternative approaches to surgical management. Minimally invasive resection of abdominal wall endometriosis with subsequent mesh reinforcement provides a surgical option with less morbidity while still accomplishing successful treatment.

Actinomyces in explanted transvaginal mesh: commensal or pathogen?

There is a paucity of information in the literature regarding the clinical impact and treatment of histologically positive actinomycosis explanted vaginal mesh. We aimed to report the prevalence and independent predicators of Actinomyces presence in explanted meshes on histology and to compare the clinical course in those with and without Actinomyces. Our hypothesis is that Actinomyces may act as a commensal rather than a pathogen when identified in extracted transvaginal meshes. A single-center retrospective review of explanted vaginal mesh removed between 2013 and 2018 was undertaken and compared Actinomyces-positive and -negative cohorts on histology. Uni- and multivariate logistic regression analysis evaluated possible risk factors for positive Actinomyces including patient demographics, smoking, diabetes, hormone replacement therapy (vaginal/systemic), hysterectomy in primary surgery, rate and indication for prior mesh removal. The rate of symptom resolution or need for subsequent mesh excisions is compared between the two cohorts. Actinomycosis was identified in 11% (31/278) of explanted mesh. After multivariant analysis, only voiding dysfunction as an indication for mesh removal was statistically significantly associated with Actinomyces-negative histology (14 vs 0%, p < 0.001). At median review of 17months, symptom resolution (87% vs 83% p = 0.68) and need for subsequent mesh removal (13% vs 19%, p = 0.37) following index mesh excision were similar between the groups. Actinomyces in explanted transvaginal mesh frequently acts as a commensal in those who are infection free. In this cohort, individualized care including conservative surveillance without antibiotics or full explantation is reasonable.

Sharp algebraic and total a posteriori error bounds for [formula omitted] and [formula omitted] finite elements via a multilevel approach. Recovering mass balance in any situation

We present novel H(div) and H1 liftings of given piecewise polynomials over a hierarchy of simplicial meshes, based on a global solve on the coarsest mesh and on local solves on patches of mesh elements around vertices on subsequent mesh levels. This in particular allows to lift a given algebraic residual. In connection with approaches lifting the total residual, we show how to obtain guaranteed, fully computable, and constant-free upper and lower a posteriori bounds on the algebraic, total, and discretization errors; here we consider the model Poisson equation discretized by the conforming finite element method of arbitrary order and including an arbitrary iterative solver. We next formulate safe stopping criteria ensuring that the algebraic error does not dominate the total error. We also prove efficiency, i.e., equivalence of our upper total and algebraic estimates with the total and algebraic errors, respectively, up to a generic constant; this constant is polynomial-degree-independent for the total error. Numerical experiments illustrate sharp control of all error components and accurate prediction of their spatial distribution in several test problems, including cases where some classical estimators fail. The H(div)-liftings at the same time allow to recover mass balance for any problem, any numerical discretization, and any situation such as inexact solution of (nonlinear) algebraic systems or algorithm failure, which we believe is of independent interest. We demonstrate this mass balance recovery in a simulation of immiscible incompressible two-phase flow in porous media.

Prolapse Recurrence After Sacrocolpopexy Mesh Removal: A Retrospective Cohort Study.

There is limited literature regarding outcomes after sacrocolpopexy mesh removal. We sought to compare the proportion of prolapse recurrence in women after sacrocolpopexy mesh removal with women who underwent sacrocolpopexy without subsequent mesh removal. We hypothesize that more women will experience prolapse recurrence after mesh removal. This is a retrospective cohort study of women who underwent sacrocolpopexy mesh removal between 2010 and 2019. These patients were time matched with women who had a sacrocolpopexy but did not undergo mesh removal. Prolapse recurrence was defined as the leading edge past the hymen or retreatment. Analysis was done using χ, Wilcoxon rank-sum, or t test with a Cox proportional hazard model to assess the association between mesh removal and time to recurrence. We identified 26 mesh removals, which were matched with 78 patients without mesh removal. The most common indications for mesh removal were exposure (69.2%) and pain (57.7%). Women who underwent mesh removal were more likely to have Mersilene mesh (19.2% vs 1.3%, P = 0.006). Recurrence occurred in 46% of women who had mesh removal compared with 7.7% in those without (P < 0.001). When adjusted for age, parity, menopause, smoking, and diabetes status, those who had mesh removal had a 15 times higher hazard of prolapse recurrence (adjusted hazard ratio = 15.4, 95% confidence interval = 4.3-54.8, P = <.0001). When compared with time-matched controls, women who underwent sacrocolpopexy mesh removal had a significantly higher proportion of prolapse recurrence. Prospective studies are needed to further explore the utility of concomitant prolapse repair at the time of mesh removal.

Weakly Supported Plane Surface Reconstruction via Plane Segmentation Guided Point Cloud Enhancement

Most of the widely used multi-view 3D reconstruction algorithms assume that object appearance is predominantly diffuse and full of good texture. For the objects that violate this restriction, the surface can hardly be reconstructed because such area lacks sufficient support from dense point clouds. To tackle this problem, we introduce a novel two-stage prior-guided method based on point clouds enhancement to enable the application of multi-view reconstruction approaches in such scenes. In the first stage, we optimize the original PlaneNet plane segmentation priors by taking advantage of the estimated depth map and confidence map from multi-view stereo. In the second stage, we correct and supply 3D point clouds for the weakly supported plane surface on the basis of the upgraded priors. Furthermore, we utilize a slight disturbance of the enhanced point clouds to facilitate the subsequent mesh reconstruction. The proposed point cloud enhancement approach is evaluated on the large-scale $DTU$ dataset. Our method significantly outperforms previous multi-view stereo state-of-the-arts. We also demonstrate weakly supported plane surface reconstruction results from real-world photos that are unachievable with either the methods aiming at preserving weakly supported surfaces or the traditional state-of-the-art 3D reconstruction systems.

Virtual element method for computational homogenization of composite and heterogeneous materials

In this study, a two-dimensional multi-region framework, based on the use of the Virtual Element Method (VEM), is developed for computational materials homogenization and applied to different classes of widely employed heterogeneous materials. The VEM has recently emerged as a powerful generalisation of the Finite Element Method capable of dealing with very general polygonal mesh elements, including non-convex or highly distorted elements. Such features are appealing for the treatment of problems whose analysis domains present complex or statistical morphological features, which would generally require careful and time-consuming mesh/data preparation and regularization. In this work, the lowest-order VEM for two-dimensional elastostatics is employed for the homogenization of polycrystalline materials and unidirectional fibre-reinforced composites. In both cases, artificial micro-morphologies are usually generated resorting to automatic algorithms aimed at approximating/reproducing the statistical microscopic features of real materials. In such a context, the likely presence of morphological irregularities, and subsequent mesh distortions, usually requires caution and the employment of sophisticated mesh regularization procedures. The study demonstrates how the inherent features of the VEM can be conveniently exploited for such classes of problems, as the method allows the relaxation of the requirements on the mesh quality, yet providing accurate numerical results.

Numerical simulation of metal forming processes with 3D adaptive Remeshing strategy based on a posteriori error estimation

In this work, a fully automated adaptive remeshing strategy, based on a tetrahedral element for 3D metal forming processes, was proposed in order to solve problems associated with the severe mesh distortion that occurs during the computation. The main idea is to use the h-type adaptive mesh in combination with an a-posteriori error estimator measured (by the energy norm) on each finite elements to locally control the mesh modification-as-needed. Once a new mesh is generated, all history-dependent variables must be carefully transferred between subsequent meshes. Therefore, several transfer techniques are described and compared. A special attention is given to restore the local mechanical equilibrium of the system with a new methodology. After presenting the necessary adaptive remeshing steps, some 3D analytic and numerical results using the proposed adaptive strategy are given to demonstrate the capabilities of the proposed equilibrated approach and to illustrate some practical characteristics of our remeshing process.

Synthesis of 3D Models of a Unipolar Inductor Machine

Like-pole reluctance machines with one or more permanent magnets on a rotor, which create net excitation that is closed in the axial–radial direction, are analyzed. Design practices are developed for them that have to be checked via basic methods. One such method is the finite-element technique, or grid method. However, it cannot be applied in the form of a two-dimensional model for the structure under analysis. Hence, a method is presented for constructing three-dimensional models of unipolar inductor machines. The construction is performed by extruding (pressing out) areas of the sector, which outline tooth or pole partition in a plane that is perpendicular to the axis of rotation, coated with projections of boundaries of all axially placed cylindrical sections of the same cutset within each section, forming a 3D model of a stator or a rotor. The method is designed for subsequent mesh generation and for calculation by means of the finite-element method related to magnetic scalar potentials, followed by determination of energy gain and rotating electromagnetic torque, defined by change of a magnetic field energy before and after the rotor is rotated by some basic angle. The described method of creating 3D models is also studied in application to like-pole machines with electromagnetic excitation on the part of a stator. In addition, it is applicable to creating models intended for examining leakage fields in the sphere of the front parts of machines by ordinary geometry reduced to a two-dimensional one.

Digital Rocks. An integrated approach to rock art recording: the case study of Ossimo-Pat (Valle Camonica), monolith 23

This paper addresses the different methods of recording prehistoric rock art, with specific focus on the northern Italian area (Valle Camonica, UNESCO Site n. 94), and presents a new integrated way of recording and tracing engravings. This method combines different sources of data, both traditional, as an ‘enhanced’ way of rubbing, and technological. The active use of Structure from Motion photogrammetry and the subsequent mesh manipulation, as well as the implementation of digital macrophotography with artificial oblique lighting, are among the methods used for the recognition of the correct features of the carvings, while the tracing of the engraved figures, executed in vector graphics, is structured on layers. Combining the benefits of the digitally enhanced visibility of the figures with the precision and versatility of digital vector drawing, this method produces state of the art tracings of rock art, for a better comprehension of the symbols carved on the stone. All steps of this method are demonstratedusing, as a selected case study, the unpublished monolith n. 23 from the Copper Age Sanctuary of Ossimo, Pat (BS) in Valle Camonica, Northern Italy.

Curvature-adapted remeshing of CAD surfaces

A common representation of surfaces with complicated topology and geometry is through composite parametric surfaces. This is the case for most CAD modelers. The majority of these models focus on having a good approximation of the surface itself, but they are usually built without taking into account a subsequent mesh generation. Indeed they are often characterized by too many patches which are not logically connected and make a standard mesh generator fail. In this work, we present a novel mesh generation strategy that can handle such “bad” input data and produces an anisotropic curvature-adapted surface mesh. There are two main ingredients to achieve this goal. First of all, we define a new and fast way to project point on an input model which overcomes the presence of non-connected patches. Then we consider the higher embedding strategy to build the final anisotropic surface mesh.

Numerical analysis of a Picard multilevel stabilization of mixed finite volume method for the 2D/3D incompressible flow with large data

In this article, we develop a branch of nonsingular solutions of a Picard multilevel stabilization of mixed finite volume method for the 2D/3D stationary Navier‐Stokes equations without relying on the unique solution condition. The method presented consists of capturing almost all information of initial problem (the nonlinear problems) on the coarsest mesh and then performs one Picard defect correction (the linear problems) on each subsequent mesh based on previous information thus only solving one large linear systems. What is more, the method presented can results in a better coefficient matrix in the model presented with small viscosity. Theoretical results show that the method presented is derived with the convergence rate of the same order as the corresponding finite volume method/finite element method solving the stationary Navier‐Stokes equations on a fine mesh. Therefore, the method presented is definitely more efficient than the standard finite volume method/finite element method. Finally, numerical experiments clearly show the efficiency of the method presented for solving the stationary Navier‐Stokes equations.© 2017 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 34: 30–50, 2018

Laparoendoscopic stapled rives stoppa sublay technique for extraperitoneal ventral hernia repair

Laparoscopic and robotic extraperitoneal ventral hernia repair techniques have developed with the goal of combining the benefits of traditional open sublay repair with those of minimally invasive surgery. We describe the use of a laparoendoscopic extraperitoneal sublay repair employing a linear stapler for plication and division of the linea alba with subsequent mesh augmentation. Between January 2016 and February 2017, 21 patients with midline ventral and incisional hernias underwent repair using a laparoendoscopic extraperitoneal stapled sublay mesh repair. Six of the cases included simultaneous laparoscopic bilateral posterior component separation with division of the posterior lamella of the internal oblique muscle. Three of these had additional myofascial release of the transversus abdominis muscle to facilitate midline approximation. Intraoperative and perioperative complications, recurrence, pain, and narcotic usage were measured. Defect width ranged from 3 to 9 cm. No significant intraoperative complications or conversions to open surgery occurred. Patients were discharged at 0.9 days on average. Early postoperative complications included hernia site seroma in two patients. There were no early postoperative infections of recurrences. One patient underwent local exploration at 6 months to remove a palpable suprafascial retained hernia sac. Compared with traditional laparoscopic intraperitoneal onlay mesh repair, less acute pain was reported. Laparoendoscopic extraperitoneal stapled sublay is a safe and effective method for small to medium-sized ventral and incisional hernias and adds another option to achieve minimally invasive extraperitoneal ventral hernia repair.

Titanium mesh implants exposure after cranioplasty in two children: involvement of osteogenesis?

BackgroundAlthough technically regarded as a simple procedure, titanium mesh cranioplasty could lead to various surgical complications, including postoperative implant exposure. However, there is little data available on the occurrence and risk factors of this complication in the pediatric population.Cases presentationTwo pediatric male patients, one 12-year-old and one 7-year-old, had decompressive craniectomy after traumatic brain injuries and subsequent cranioplasty with titanium mesh. However, both patients had skin defects developed gradually at the scalp adjacent to the surgical incisions, 11 and 7 months after cranioplasty, respectively. Implants removal surgeries were then delivered and, during the operation, some bone debris were found just beneath the skin defects in both patients. Because microbiological culture results of the exudations were negative, in addition to the long interval between cranioplasty and developments of skin defects, surgical infections might not be major causes of the observed titanium implants exposures. On the other hand, local osteogenesis and impaired scalp blood supply might contribute to their occurrence.ConclusionsEfforts should be made to achieve complete clearance of bone debris and protect scalp blood supply during the initial decompressive craniectomy in order to minimize the risks of subsequent titanium mesh exposures.

Association Between the Amount of Vaginal Mesh Used With Mesh Erosions and Repeated Surgery After Repairing Pelvic Organ Prolapse and Stress Urinary Incontinence

Mesh, a synthetic graft, has been used in pelvic organ prolapse (POP) repair and stress urinary incontinence (SUI) to augment and strengthen weakened tissue. Polypropylene mesh has come under scrutiny by the US Food and Drug Administration. To examine the rates of mesh complications and invasive reintervention after the placement of vaginal mesh for POP repair or SUI surgery. This investigation was an observational cohort study at inpatient and ambulatory surgery settings in New York State. Participants were women who underwent transvaginal repair for POP or SUI with mesh between January 1, 2008, and December 31, 2012, and were followed up through December 31, 2013. They were divided into the following 4 groups based on the amount of mesh exposure: transvaginal POP repair surgery with mesh and concurrent sling use (vaginal mesh plus sling group), transvaginal POP repair with mesh and no concurrent sling use (vaginal mesh group), transvaginal POP repair without mesh but concurrent sling use for SUI (POP sling group), and sling for SUI alone (SUI sling group). The primary outcome was the occurrence of mesh complications and repeated invasive intervention within 1 year after the initial mesh implantation. A time-to-event analysis was performed to examine the occurrence of mesh erosions and subsequent reintervention. Secondary analyses of an age association (<65 vs ≥65 years) were conducted. The study identified 41 604 women who underwent 1 of the 4 procedures. The mean (SD) age of women at their initial mesh implantation was 56.2 (13.0) years. The highest risk of erosions was found in the vaginal mesh plus sling group (2.72%; 95% CI, 2.31%-3.21%) and the lowest in the SUI sling group (1.57%; 95% CI, 1.41%-1.74%). The risk of repeated surgery with concomitant erosion diagnosis was also the highest in the vaginal mesh plus sling group (2.13%; 95% CI, 1.76%-2.56%) and the lowest in the SUI sling group (1.16%; 95% CI, 1.03%-1.31%). The combined use of POP mesh and SUI mesh sling was associated with the highest erosion and repeated intervention risk, while mesh sling alone had the lowest erosion and repeated intervention risk. There is evidence for a dose-response relationship between the amount of mesh used and subsequent mesh erosions, complications, and invasive repeated intervention.

A new functional a posteriori error estimate for problems of bending of Timoshenko beams

In this paper a new functional a posteriori error estimate is obtained for problems of bending of curvilinear Timoshenko beams. For sake of simplicity clamped beams under the action of traverse and axial forces and bending moment are considered. The derived estimate is reliable, is applicable to any conforming approximation and can be used both for global accuracy control and for local error indication for subsequent mesh adaptation. Its theoretical properties are confirmed by results of numerical experiments.

Adaptive isogeometric analysis based on a combined r-h strategy

ABSTRACTIn the present work, an r-h adaptive isogeometric analysis is proposed for plane elasticity problems. For performing the r-adaption, the control net is considered to be a network of springs with the individual spring stiffness values being proportional to the error estimated at the control points. While preserving the boundary control points, relocation of only the interior control points is made by adopting a successive relaxation approach to achieve the equilibrium of spring system. To suit the noninterpolatory nature of the isogeometric approximation, a new point-wise error estimate for the h-refinement is proposed. To evaluate the point-wise error, hierarchical B-spline functions in Sobolev spaces are considered. The proposed adaptive h-refinement strategy is based on using De-Casteljau’s algorithm for obtaining the new control points. The subsequent control meshes are thus obtained by using a recursive subdivision of reference control mesh. Such a strategy ensures that the control points lie in the physical domain in subsequent refinements, thus making the physical mesh to exactly interpolate the control mesh and thereby allowing the exact imposition of essential boundary conditions in the classical isogeometric analysis (IGA). The combined r-h adaptive refinement strategy results in better convergence characteristics with reduced errors than r- or h-refinement. Several numerical examples are presented to illustrate the efficiency of the proposed approach.

Open and Laparo-Endoscopic Repair of Incarcerated Abdominal Wall Hernias by the Use of Biological and Biosynthetic Meshes.

Although recently published guidelines recommend against the use of synthetic non-absorbable materials in cases of potentially contaminated or contaminated surgical fields due to the increased risk of infection (1, 2), the use of bio-prosthetic meshes for abdominal wall or ventral hernia repair is still controversially discussed in such cases. Bio-prosthetic meshes have been recommended due to less susceptibility for infection and the decreased risk of subsequent mesh explantation. The purpose of this review is to elucidate if there are any indications for the use of biological and biosynthetic meshes in incarcerated abdominal wall hernias based on the recently published literature. A literature search of the Medline database using the PubMed search engine, using the keywords returned 486 articles up to June 2015. The full text of 486 articles was assessed and 13 relevant papers were identified including 5 retrospective case cohort studies, 2 case-controlled studies, and 6 case series. The results of Franklin et al. (3-5) included the highest number of biological mesh repairs (Surgisis(®)) by laparoscopic IPOM in infected fields, which demonstrated a very low incidence of infection and recurrence (0.7 and 5.2%). Han et al. (6) reported in his retrospective study, the highest number of treated patients due to incarcerated hernias by open approach using acellular dermal matrix (ADM(®)) with very low rate of infection as well as recurrences (1.6 and 15.9%). Both studies achieved acceptable outcome in a follow-up of at least 3.5 years compared to the use of synthetic mesh in this high-risk population (7). Currently, there is a very limited evidence for the use of biological and biosynthetic meshes in strangulated hernias in either open or laparo-endoscopic repair. Finally, there is an urgent need to start with randomized controlled comparative trials as well as to support registries with data to achieve more knowledge for tailored indication for the use of biological meshes.