Mesh Patch Research Articles

Multifunctional Double Band Mesh Antenna with Solar Cell Integration for Communications Purposes

A dual band flexible antenna based on a circularly polarized modified meshed patch antenna design. This article focuses on some of the most pressing issues in small satellite applications. The antenna optimization and improvement of antenna performance, such as radiation efficiency. As is well known, circular polarization is immune to the Faraday rotation effect in the ionosphere and can thus prevent a 3-dB loss in geo-satellite communication. With the use of the software program Computer Simulation Technology (CST), the proposed circularly polarized modified meshed patch antenna has been created. Therefore, this article also presents a modified design of a circularly polarized meshed patch antenna to reduce the complexity of the antenna and decrease the size as much as it is capable. However, a meshed patch antenna can support a high communication data rate. The antenna architecture will theoretically be consistent with the installation of solar panels. The antenna utilizes a conductive copper as the core material and the substrate using flexible polyimide. The design antenna is very small, having an overall size of 30 * 30 mm when compared to other conventional non-transparent antenna operating at the same frequencies of 2.6, 3.5 GHz. The antenna that is proposed involves two meshed patch elements of same size but in various shapes. Finally, the proposed antenna is integrated into a solar cell by using the amorphous silicon thin film.

A Novel Computational Paradigm for Reconstructing Solid CAD Features from a Segmented Manifold Triangular Mesh

We introduce a novel computational paradigm for reconstructing solid computer-aided design (CAD) features from the surface of a segmented manifold triangular mesh. This paradigm addresses the challenge of capturing high-level design semantics for manifold triangular meshes and facilitates parametric and variational design capabilities. We categorize four prevalent features, namely extrusion, rotation, sweep, and loft, as generalized swept bodies driven by cross-sectional sketches and feature paths, providing a unified mathematical representation for various feature types. The numerical optimization-based approach conducts geometric processing on the segmented manifold triangular mesh patch, extracting cross-sectional sketch curves and feature paths from its surface, and then reconstructing appropriate features using the Open CASCADE kernel. We employ the personalized three-dimensional (3D) printed model as a case study. Parametric and variant designs of the 3D-printed models are achieved through feature reconstruction of the manifold triangular mesh obtained via 3D scanning.

A tri-band low-profile shared-aperture mesh patch/Fabry-Perot cavity antenna

ABSTRACT A tri-band low-profile shared-aperture antenna is proposed. Based on structural multiplexing, a mesh patch is proposed to function as part of the partial reflective surface (PRS) of the Fabry-Perot cavity antenna (FPCA) in the middle- and high-frequency bands, as well as to function as the radiator of the patch antenna in the low-frequency band. Thus, the FPCA and the mesh patch antenna share the same aperture. A dual-band PRS is proposed, which can adjust its reflection amplitude independently in two frequency bands. By introducing artificial magnetic conductor (AMC) grounding to compensate for the transmission phase of the middle-frequency band, the proposed antenna can realize dual-band FPC resonance in a single cavity while maintaining a low profile. To validate the design concept, an antenna prototype is fabricated and measured. Measured results show that the impedance bandwidths of the proposed antenna are 4.74% (1.03–1.08 GHz), 0.42% (4.79–4.81 GHz), and 3.83% (11.52–11.97 GHz). The peak gain is 7.85 dBi at 1.06 GHz, 12.47 dBi at 4.81 GHz, and 20.6 dBi at 11.7 GHz. The isolation between the three bands is better than 30 dB. The three operating bands of the proposed antenna have a high degree of independence and can be flexibly adjusted.

2-Octyl-Cyanoacrylate Mesh Dressings for Total Joint Arthroplasty: Dressing Design Influences Risks of Wound Complications

BackgroundRecent liquid adhesive skin closure systems with a mesh patch and a 2-octyl cyanoacrylate liquid formula have shown promising results in total joint arthroplasty. Chemical accelerators are typically included to promote the rapid polymerization of 2-octyl cyanoacrylate. The goal of the study is to distinguish designs and wound complication differences between 2 similar systems. MethodsAn 18-week retrospective study was conducted from July to December 2023, including 207 total hip arthroplasty and 212 total knee arthroplasty cases from 4 attending surgeons at 1 institution that used 1 of 2 dressing designs. Both dressings had a 2-octyl cyanoacrylate liquid adhesive formula that applied topically to a polyester-based mesh overlaying the wound. Mesh A (used in 274 cases) included an accelerator, a quaternary ammonium salt, on the mesh patch, whereas Mesh B (used in 145 cases) included a similar accelerator within the adhesive applicator. ResultsWound complications (3.2 versus 7.6%; X2 = 3.86; df = 1; P = .049), early periprosthetic joint infections (0 versus 2.8%; X2 = 7.63; df = 1; P = .006), and 90-day reoperations for wound complications (0.4 versus 3.4%; X2 = 6.39; df = 1; P = .011) were significantly lower in patients who received Mesh A versus B, respectively. There was no difference in superficial surgical site infections (0.7 versus 0%; X2 = 1.06; df = 1; P = .302) or allergy rates (3.3 versus 4.1%; X2 = 0.12; df = 1; P = .655) between Mesh A and B. ConclusionsWe observed significantly different performance in wound complications, early postoperative periprosthetic joint infections, and 90-day reoperation between the 2 designs. Having the accelerator in the applicator rather than on the mesh patch may lead to premature polymerization before bonding appropriately with the mesh to create the desired wound closure and seal. Level of EvidenceLevel III.

LOSS OF DRAINAGE VACUUM AFTER MINIMAL INVASIVE SUBLAY OPERATION – EARLY INDICATOR FOR AN INTERPARIETAL HERNIA WITH SMALL BOWEL OBSTRUCTION – A CASE REPORT

Abstract Background Newer repair techniques for abdominal wall hernias, such as the enchanced-view totally extraperitoneal technique or the mini- or less-open sublay operation are increasingly being used. With these new techniques special complications might occur. Case Report We present an 81-year-old patient with a recurrent ventral incisional hernia after IPOM repair. The preoperative abdominal CT scan showed the hernia defect, measuring 3 × 3 cm. A repair was performed in MILOS technique, the IPOM mesh was removed. The posterior the rectus sheath was closed under slight tension. A Mesh 15 × 15 cm without fixation and a 14 french Redon drainage were inserted. Over the next 4 postoperative days the drainage had a repeatedly loos of vacuum, until the patient developed clinical symptoms of a ileus. A CT scan showed a bowel dysfunction without a clear sign for incarceration. At this point, the suction drainage was without vacuum a total of seven times. A diagnostic laparoscopy was performed and a small bowel loop was found trapped between the implanted mesh and the posterior rectus sheath, as an interparietal retro-rectus hernia (iRRH). The intestinal loop could be removed, no necrosis or ischemia was found. The fascial defect was covered using vicryl mesh patch. Conclusion The role of vacuum drainage remains to be considered. Suction of remaining intraabdominal gas might occur due to fascia dehiscence and CT diagnostics can mislead surgeons decisions. Tension free fascial closure remains of capital importance. Mesh fixation, use of special stitching techniques, transversus-abdominis-release or preoperative application of botulinum toxin should be kept mind.

Composite patch with negative Poisson's ratio mimicking cardiac mechanical properties: Design, experiment and simulation

Developing patches that effectively merge intrinsic deformation characteristics of cardiac with superior tunable mechanical properties remains a crucial biomedical pursuit. Currently used traditional block-shaped or mesh patches, typically incorporating a positive Poisson's ratio, often fall short of matching the deformation characteristics of cardiac tissue satisfactorily, thus often diminishing their repairing capability. By introducing auxeticity into the cardiac patches, this study is trying to present a beneficial approach to address these shortcomings of the traditional patches. The patches, featuring the auxetic effect, offer unparalleled conformity to the cardiac complex mechanical challenges. Initially, scaffolds demonstrating the auxetic effect were designed by merging chiral rotation and concave angle units, followed by integrating scaffolds with a composite hydrogel through thermally triggering, ensuring excellent biocompatibility closely mirroring heart tissue. Tensile tests revealed that auxetic patches possessed superior elasticity and strain capacity exceeding cardiac tissue's physiological activity. Notably, Model III showed an equivalent modulus ratio and Poisson's ratio closely toward cardiac tissue, underscoring its outstanding mechanical potential as cardiac patches. Cyclic tensile loading tests demonstrated that Model III withstood continuous heartbeats, showcasing outstanding cyclic loading and recovery capabilities. Numerical simulations further elucidated the deformation and failure mechanisms of these patches, leading to an exploration of influence on mechanical properties with alternative design parameters, which enabled the customization of mechanical strength and Poisson's ratio. Therefore, this research presents substantial potential for designing cardiac auxetic patches that can emulate the deformation properties of cardiac tissue and possess adjustable mechanical parameters.

Injectable Mesh-Like Conductive Hydrogel Patch for Elimination of Atrial Fibrillation.

Irregular electrical impulses in atrium are the leading cause of atrial fibrillation (AF), resulting in fatal arrhythmia and sudden cardiac death. Traditional medication and physical therapies are widely used, but generally suffer problems in serious physical damage and high surgical risks. Flexible and soft implants have great potential to be a novel approach for heart diseases therapy. A conductive hydrogel-based mesh cardiac patch is developed for application in AF elimination. The designed mesh patch with rhombic-shaped structure exhibits excellent flexibility, surface conformability, and deformation compliance, making it fit well with heart surface and accommodate to the deformation during heart beating. Moreover, the mechanical elastic and shape-memory properties of the mesh patch enable a minimally invasive injection of the patch into living animals. The mesh patch is implanted on the atrium surface for one month, indicating good biocompatibility and stability. Furthermore, the conductive patch can effectively eliminate AF owing to the conductivity and high charge storage capability (CSC) of the hydrogel. The proposed scheme of cardiac bioelectric signal modulation using conductive hydrogel brings new possibility for the treatment of arrhythmia diseases.

Performance Evaluation of a Low-Cost Semitransparent 3D-Printed Mesh Patch Antenna for Urban Communication Applications

This study explores the possibility of designing simple semitransparent antennas that allow for the passage of most visible light while maintaining good electromagnetic performance. We propose a substrateless metal mesh patch antenna manufactured using low-cost 3D printing and silver conductive paint. Our goal is to integrate numerous such radiators onto office building windows, preserving natural lighting with minimal visual impact, aiming to alleviate infrastructure congestion or improve antenna placement in sub-6 GHz frequency bands. In this paper, we conduct an analysis of the primary parameters influencing patches constructed with substrateless metal mesh wires, focusing on the grid topology and the width of the metallic wires, as well as their effects on antenna transparency and back radiation. Owing to the absence of a substrate, the antenna demonstrates minimal losses. Furthermore, in this study, we thoroughly investigate the effects of conductivity and roughness on surfaces printed with metallic paint. A prototype at 2.6 GHz is presented, achieving over 60% transparency, a 2.7% impedance-matching bandwidth, and a realized peak gain of 5.4 dBi. The antenna is easy to manufacture and cost-effective and considers sustainability. Its large-scale implementation can alleviate building infrastructure, enhancing radio connectivity in urban environments and offering new cost-effective and energy-efficient wireless solutions.

A compact hybrid solar and electromagnetic energy harvester at 2.45 GHz microstrip rectenna

This paper presents a compact rectenna integrated with a packaged solar cell to convert a hybrid (solar + electromagnetic) energy to DC energy. The packaged solar cell used as the substrate is sandwiched between a meshed patch and a rectifying circuit. Based on particle swarm algorithm, the meshed patch with high transparency (96.2 % transmittance) is mounted on the surface of the solar cell. By using a copper rod, the high-efficient rectifying circuit is connected with the meshed patch through the solar cell. Due to the high-integrated hybrid energy harvester, the solar and radio frequency (RF) energies can be absorbed and converted to DC power separately or simultaneously. The measured maximum RF-DC conversion efficiency of the rectenna acquires 73 % under the input power of the antenna of 17 dBm, and the maximum DC power of 60.6 mW is generated when the solar cell is illuminated with standard global AM1.5 illumination conditions. The measured DC combining efficiency of 96.8 % is achieved from the hybrid solar rectenna, with the optimal load of 400 Ω. Furthermore, the design method is extended to harvesting ambient electromagnetic energy, and a low-power rectifying circuit with conversion efficiency of 59.6 % at input power of −10 dBm is designed.

Enhanced honey badger optimization of performance analysis of evacuated tube heat pipe solar collector integrated with PCM storage unit

A hybrid method for improving the efficiency of heat pipe evacuated-tube solar-collector (HPETC) is proposed for incorporating the phase-change materials (PCMs) in both off-demand and regular operation. The proposed hybrid approach is called an improved honey badger algorithm (HBA). The crossover and mutation operator improves the honey badger's (HB) foraging habit. The proposed approach aims to generate hot air at various rates of airflow under incident and nonincident solar-radiation situations. The analysis is done on the effects of different energy-storage systems and the position of the heat pipe (HP). In a normal heat-pipe evacuated-tube solar collector, the HP is put within the glass tube that is closer to the upper-surface, and it is held in place through an aluminum fin. However, in the proposed method, the HP is rearranged in the tube's middle. In order to identify the PCM with the highest average-fin temperature, the temperatures of the area-weighted average-fin are measured and compared throughout the glass tubes under typical conditions. For maximizing the thermal-energy carrying capability, the average liquid fraction volume of PCMs is measured for a 24-h flow period. The average liquid-fraction volume of PCMs is continuously observed in stagnation mode till the glass tube reaches the maximal value. The structured mesh patch conforming method is used to invalidate the HPETC system's constituent parts, improving numerical stability and convergence. The proposed method efficiency is 0.43. The proposed method shows high efficiency compared with other existing methods.

P-094 FLAT PATCH MESH VERSUS THREE-DIMENSIONAL MESH (PLUG) FOR OPEN UMBILICAL OR EPIGASTRIC HERNIA REPAIR: A RETROSPECTIVE STUDY

Abstract Aim The aim of this retrospective study was to compare open small- and medium-sized ventral hernia repair with flat patch mesh versus three-dimensional mesh (plug) in terms of recurrence and complication rates. Methods The medical records of 300 patients who underwent ventral hernia repair using flat mesh versus plug between January 2010 to December 2015 were reviewed. All patients were followed up after 1 month, 3 month and 1 year. The rate of recurrence, and short-term postoperative complications such as incidence of Surgical Site Infections (SSIs), hematoma and seroma were evaluated. Results Short-term follow-up data were available for all patients. The first group was composed of 150 patients that were treated with plug (60% presented umbilical hernia and 40% presented epigastric hernia). The second group was composed of 150 patients that were treated with flat mesh (68% presened umbilical hernia and 32% presented epigastric hernia). The majority of postoperative complications were wound related, representing superficial SSI or seroma. Our results showed a statistically significant reduction of SSIs [3 (2%) vs 13 (8.6%); p = 0.038] and seroma [2 (1.3%) vs 12 (8%); p = 0.030] in the group of patients treated with plugs. There was no statistically significant difference in hernia recurrences. Conclusions Usage of plugs represents a feasible and safe technique that significantly lowers the incidence of complications. Furthermore, compared to flat mesh, plugs displayed non-inferiority in terms recurrence. Further, well-designed clinical trials could be realized to investigate possible applications of plugs for umbilical and epigastric hernias repair.

Patch Repair for Intestinal Perforation Closure in an Ex-Vivo Porcine Model with Burst Pressure Characterization

Background: Bowel perforation is the loss of intestinal wall integrity and can occur by several mechanisms including infection, obstruction, inflammation, trauma and iatrogenic causes. Incidences of bowel perforation range from 1-7% in pediatric trauma patients and 0.02-8% in adults. There is no specific classification for gastrointestinal perforations, but several methods have been used to describe perforations based on etiology, including systemic, inflammatory, medication, neoplastic and instrumentation-induced perforations. We assessed the feasibility of closing small intestine perforations with a mesh patch instead of sutures only. Methods and Findings: Nine porcine ex-vivo small intestine specimens were incised 0.5 cm to simulate bowel perforations. Control group perforations were sutured closed without mesh. The two experimental groups were closed by mesh sewn to the outside (first group) or inside (second group) of the bowel wall. Each specimen was submerged in normal saline and insufflated until air bubbles leaked from the perforation. That insufflation pressure was recorded as the burst pressure. The control group burst at 78.0±17.9 mmHg. The “patch outside” group burst at 54.7±9.1 mmHg. The “patch inside” group burst at 32.0 ±4.6 mmHg. Only the “patch inside” group had statistically significant inferiority, but both groups trended towards inferiority. Conclusions: Preliminary research indicates that patch repair of intestinal perforations is likely inferior to sutures alone, although repair with the patch outside the bowel wall cannot be completely excluded because of the high variability of the data. Further research may try alternate patch types or different variations to find a non-inferior closure method. A sample size of n=9 each would give 80% power to detect a minimal detectable difference of 20 mmHg.

Formation of Biologic Plug and Patch Mesh for Use in Perforated Femoral Hernia.

Incarcerated inguinal hernias with contamination frequently lead to an open inguinal hernia primary repair. If no contamination is present, a tension-free repair with mesh is a good option. In this case, we encountered an incarcerated femoral hernia with perforation of the small bowel. We will describe and demonstrate via video how to incorporate a tension-free repair with mesh in a contaminated field with formation of a plug and patch made from biologic mesh.

Intraperitoneal onlay mesh versus laparoscopy-assisted ventral hernia patch mesh repair in small primary ventral hernias

Aims: The aim of this study is to compare and evaluate short-term outcomes of laparoscopy-assisted composite patch mesh repair versus laparoscopic intraperitoneal onlay mesh in small primary midline ventral hernias. Materials and Methods: Eighty consecutive patients with small (<2 cm) midline ventral hernia admitted to the Department of General and Laparoscopic surgery at Sir Ganga Ram Hospital, New Delhi, from January 2017 to May 2019 were included in the study and randomised into two groups. Group A included patients who underwent laparoscopic intraperitoneal onlay mesh repair with the classical barrier flat mesh and Group B patients underwent laparoscopy-assisted ventral hernia patch-mesh repair. Parameters assessed at the follow-up were early post-operative pain by Visual Analogue Scale score, wound complications, early recurrence and hospital stay. Results: Early post-operative pain was more in the laparoscopic intraperitoneal onlay mesh group and the difference was statistically significant. Usage of additional analgesia in the post-operative period was required only in the laparoscopic intraperitoneal onlay mesh group. There was a statistically significant difference between the two groups in terms of hospital stay. Conclusion: For primary midline ventral hernia, with defect size <2 cm, laparoscopy-assisted composite patch mesh repair is feasible and safe. It causes less pain and necessitates less usage of additional analgesia enabling patients to be discharged earlier.

A Dual Wideband Compact Shared-Aperture Microstrip Patch/Fabry–Perot Resonator Cavity Antenna

In this article, a dual wideband compact shared-aperture microstrip patch/Fabry–Perot resonator cavity antenna is proposed. A reflective meshed patch is designed to conduct as the shared surface, which works as the radiator at the lower band but the partial reflective sheet (PRS) at the upper band. A transmissive meshed patch is designed as the parasitic element to broaden the lower bandwidth without influence on the upper band radiation. The shaped ground is used to improve the front-to-back ratio at the lower band while maintaining a compact size. Moreover, the reflective meshed patch, which is built by two complementary frequency selective structures (FSSs), shows a positive reflection phase gradient to broaden the bandwidth of the antenna at the upper band without influence on the lower band radiation. The measurements reveal that a common bandwidth of ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\vert \text{S}_{11(22)}\vert &lt; -10$ </tex-math></inline-formula> dB, gain reduction < 3 dB) 25.4% and 21.3%, an isolation higher than 40 and 22 dB, a peak gain of 9.01 and 16.6 dBi at UHF band and C-band are achieved, respectively. The above properties make the proposed antenna suitable for dual-band point-to-point line-of-sight (LOS)/non-LOS (NLOS) communication systems.

Agenesis of the left hemi-diaphragm, the cause of a neglected dyspnea in a 65-year-old female; case report and literature review

In its complex way of embryonic evolvement, the diaphragmatic membrane can be involved with various disorders that may partially or entirely not develop. Agenesis of the diaphragm is the term that refers to this maldevelopment. It is the more severe form of congenital diaphragmatic hernia in which intra-abdominal viscera protrude into the thoracic cavity, causing respiratory and gastrointestinal problems. Most neonates delivered with diaphragmatic agenesis do not live more than hours to days of the severity of lung immaturity. However, less than 20 affected cases have been reported so far that survived to childhood and even their adulthood period treated surgically or conservatively. We have reported a case of neglected left hemi-diaphragmatic agenesis for more than six decades, then reviewed all adult diaphragmatic agenesis cases available in the literature for 74 years. A 65-year-old female complaining of worsened dyspnea during the last four months, a chronic history of short breath since her fourth decade of life, and recent surgery with the diagnosis of a diaphragmatic hernia, underwent the thoracotomy twice in which unilateral diaphragmatic hernia was diagnosed then repaired. For the recurrence of her symptoms, she underwent a second thoracotomy, in which the final diagnosis of left hemi-diaphragmatic agenesis was made. A dual mesh patch constructed the defect. The post-operation period was uneventful. We only found 17 cases of adult hemi or bilateral agenesis of the diaphragm reviewing the main medical literature such as Medline and Web of Science. The conservative and operative treatment managements were equal for eight patients in each of them. One of them refused therapy, and one was non-declared in the study. As in congenital diaphragmatic hernia, the most typical side was the left in 10 out of 18. The most complaints patients had followed by coughing and bowel obstruction was dyspnea and dyspepsia. Near the total of the diaphragmatic agenesis cases die in the neonatal population; remained undiagnosed or during an autopsy found. However, typically rare in the adult population, respiratory and digestive disorders are the most prevalent. It is difficult initially because diagnosing is intraoperatively, and no modality is available to help the examiner physician diagnose perinatally.

V-018 PREOPERATIVE OPTIMIZATION AND POSTERIOR COMPONENT SEPARATION WITH INTRAOPERATIVE MONITORING OF RECTUS MUSCLE INERVATION FOR LOSS OF DOMAIN INCISIONAL HERNIA

Abstract Aim The importance of an appropriate patient optimization (botulin toxin and pneumoperitoneum) and adequate surgical technique is highlighted.The possibility of intraoperative monitoring of the nerves that may be injured during posterior component separation is explained Material and methods We present a 74 years old man, past smoker, with history of hypertension, steatohepatitis and chronic bronchopathy Results This is a disastrous but unfortunately not so uncommon story of a failed repair of a simple umbilical hernia with 3 previous unsuccessful attempts of repair with and without mesh. After the last surgery the patient developed a giant incisional hernia with loss of domain. Optimization consisted of improving nutritional status, respiratory physiotherapy, botulin toxin and pneumoperitoneum. The surgery was made using previous skin scar. After dissecting the retrorectus space, a posterior component separation was made with the aid of monitoring the nerves that come to innervate the rectus abdominis. An overextended overlapped was obtained. A patch of absorbable mesh was used to completely close the peritoneum. A combination of absorbable and permanent synthetic mesh was used as giant reinforcement of the visceral sac. The only points of fixation were the Cooper Ligaments. The patient had a satisfactory recovery without complications and was discharged on the 8th postoperative day. Conclusions Loss of domain incisional hernias is a real surgical challenge. The combination of a good preoperative strategy (preoperative neumoperitoneum) and surgical technique (TAR and pannniculectomy) gives a great opportunity to solve very complex cases of incisional hernia.

Umbilical hernia: could it be the 'canary in the coal mine' for a more significant abdominal wall problem?

A considerable proportion of incisional hernias presenting to this unit evolve following simple umbilical hernia repair. Our aim was to review our series of complex ventral hernia repairs and identify the frequency of this problem. Our secondary aim was to encourage surgeons to evaluate whether any of the factors that increase the risk of recurrent hernia may be present, prior to undertaking an umbilical hernia repair. Observational retrospective review of a prospectively maintained single-surgeon database of consecutive patients undergoing surgery for recurrent ventral hernia. Patients presenting with recurrence at the site of a previous umbilical hernia repair were identified and their demographic data collected and analysed. A review of the published literature was performed. Patient and surgeon factors contributing to recurrence were identified and discussed. Of 386 patients undergoing surgery for a recurrent ventral hernial, 102 (26.4%) were initially managed as 'simple' umbilical hernias repaired with a mesh patch or primary suture repair. 71 (69.6%) patients had undergone one or more subsequent hernia repairs prior to referral to our unit with 16 (15.6%) having had three or more repairs prior to referral. Recurrence rates after umbilical hernia repair are likely to be much higher than surgeons and patients appreciate. There are many aspects to consider in the repair of a 'simple' umbilical hernia and we seek promote a discussion amongst surgeons that umbilical hernias be assessed as a major abdominal wall condition and not relegated to minor surgery status.

Laparoscopic repair of sciatic hernia recognizing the ureterohypogastric nerve fascia and vesicohypogastric fascia: a case report

BackgroundSciatic hernias are rare pelvic floor hernias that occur through the sciatic foramen and often present as abdominal or pelvic pain, particularly in women. Historically, they were repaired using an open approach, with limited reports on their laparoscopic treatment.Case presentationHere we present the case of an 85-year-old woman who had repeated abdominal pain and was referred to our hospital for sciatic hernia surgery after conservative treatment. We laparoscopically observed the deep pelvis and identified the right sciatic hernia. When an extraperitoneal space was dissected, an ureterohypogastric nerve fascia (UNF) and a vesicohypogastric fascia (VF) were identified. Moreover, the maneuver to mobilize the fasciae inside from the pelvic wall made it possible to separate the ureter and urinary bladder, which might have otherwise incarcerated in the hernia. We repaired the defect of the sciatic foramen with a mesh plug and patch. The patient had an uneventful recovery, and the absence of sciatic herniation recurrence was confirmed 1 year after surgery.ConclusionA laparoscopic repair of a sciatic hernia could permit detailed non-invasive observations of the deep pelvis and be performed effectively by recognizing an UNF and a VF located near the sciatic foramen.

Robust and Fast CAD Model Tessellation for Inspection

The digital manufacturing deviation inspection can be used to assess the dimension, form, and position errors, which is more efficient, more consistent, and more robust than manual inspection. CAD models are used as the nominal data and compared with the scanned data of parts to obtain manufacturing errors. CAD model tessellation is a pivotal step in deviation inspection, which directly determines the reliability of analytical results. It requires that the generated triangle mesh has dense vertices, high approximation accuracy, and consistent orientation. A single surface patch tessellation method is proposed, and the adaptive quadtree is first constructed to divide the domain into small spatial grids in the parameter space of the patch; then, a clip-based method is presented to triangulate boundary grids, and inner grids could be triangulated by the constrained Delaunay triangulation method. Furthermore, the mesh patches should be spliced and reoriented consistently, which is very important for deviation analysis. To solve this problem, a robust gap healing method based on merging boundary points of patches is developed, so that all boundary vertices of adjacent patches could completely coincide along the common edges, and all mesh patches would be stitched into a complete mesh without gaps. Finally, the face normal of mesh is adjusted to obtain a consistent orientation. Experiments on industrial CAD models demonstrate that the proposed method could realize faster and more robust mesh generation than the state-of-the-art approaches, including three commercial and two open-source software.