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Background: Surgical repair of left ventricular (LV) aneurysm has been performed for around 50 years. However, the most appropriate surgical approach remains undetermined. This study was undertaken to compare the efficacy of 2 established techniques, linear versus patch remodeling, for repair of dyskinetic LV aneurysms. Methods: We retrospectively reviewed the records of 49 patients (mean age, 69.8 ± 7.3 years) who had operation for postinfarction dyskinetic LV aneurysm between 1996 and 2006. Thirty-one patients underwent patch remodeling and 18 underwent linear repair. Short-term and mid-term outcomes, including complications, cardiac function and mortality, were assessed. Results: Overall inhospital surgical mortality, major complications and early hemodynamics showed no significant differences between the 2 groups. During a mean follow-up of 44.0 ± 34.4 months, 8 patients died, with 4 due to cardiac-related causes. Actuarial survival rates at 1, 5 and 10 years were 85.7%, 69.9% and 45.7%, respectively. Functional class improved from 2.51 ± 0.59 to 1.66 ± 0.54 among the mid-term survivors (p < 0.001), with no significant difference between the 2 groups. Multivariate analysis identified preoperative NYHA functional class ≥ 3 as an independent risk factor for overall mortality (p = 0.008). Mid-term follow-up revealed that LV ejection fraction improved from 26.5 ± 7.2% to 34.1 ± 7.9% (p < 0.001) in the patch group, and from 26.3 ± 9.0% to 32.0 ± 9.2% in the linear group (p = 0.032). In contrast, right ventricular ejection fraction improved from 49.4 ± 10.1% to 52.0 ± 7.3% (p = 0.190) in the patch group, but deteriorated from 55.0 ± 6.3% to 50.3 ± 8.6% in the linear group (p = 0.029). Conclusion: These findings indicate that the 2 repair techniques have similar effectiveness with respect to short- and mid-term outcomes except for right ventricular ejection fraction. We suggest that the selection of repair technique for LV aneurysms should be individualized for each patient based on aneurysm size and extent of the scarring process into the septum and subvalvular mitral apparatus. [Copyright &y& Elsevier]

Abstract: In repair works of reinforced concrete, patch repairs tend to crack in the interfacial zone between the mortar and the old concrete. This occurs basically due to the high degree of restriction that acts on a patch repair. For this reason, the technology of patch repair needs to be the subject of a discussion involving professionals who work with projects, construction maintenance and mix proportioning of repair mortars. In the present work, a study is presented on the benefits that the ethylene vinyl acetate copolymer (EVA) and acrylate polymers can provide in the mix proportioning of a repair mortar with respect to compressive, tensile and direct-shear bond strength. The results indicated that the increase in bond strength and the reduction in the influence of the deficiency in curing conditioning are the main contributions offered by the polymers studied here. [Copyright &y& Elsevier]

Technically expedient repair of CDH defects is desirable. With increasing trend toward thoracoscopic repair, herein we examine physiologic predictors for the need for patch closure (PC) versus primary closure. All neonates who underwent surgical repair of CDH defects in a geographically defined region between 1992 and 2002 were included (n = 210). Two groups of patients were compared, primary repair (PR) versus PC. The 25th quartile was used as a cut off point for continuous variables. Univariate and multivariate logistic regression were performed. One hundred and fifty neonates underwent open PR (71.43%) versus 28.57% had PC. On univariate analyses the following variables were significantly associated with the need for PC: prenatal diagnosis, birth weight <2.7 kg, gestational age <37 weeks, APGAR at 5 min <6, immediate postnatal PCO(2) >34, Immediate oxygen saturation <93%, use of Nitric oxide and the need for high frequency oscillation (HFO). On multivariate analyses, only a PCO(2) >34 and the need for HFO were significantly associated with PC. Neonates with an initial PCO(2) >34 or need HFO pre-operatively should be excluded from attempts to repair the CDH thoracoscopically based on their higher potential need for PC with its entailed technical difficulty and increased operative time. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: Many different prosthetic materials have been used for repair of large posterolateral congenital diaphragmatic hernias (CDH), with high recurrence rates for hernias that cannot be primarily repaired. Since 1993, we have used a composite patch of Gore-Tex/Marlex to repair large CDHs and hypothesized that this repair leads to fewer recurrences. Methods: This is a retrospective review of 137 consecutive patients with CDH cared for at a single institution from 1993 to 2004. Data collected include timing and method of repair and use of extracorporeal membrane oxygenation. Outcomes include hernia recurrence, complications, and death. Results: One hundred thirty-seven patients with CDH were analyzed. Repair was not attempted in 12 because of disease severity. Primary repair was accomplished in 79 and 46 required patch repair. Of the 46 patients with patch repairs, 32 required extracorporeal membrane oxygenation, and 18 died before discharge. Of the 28 patch repair survivors, 1 (3.57%) developed a recurrence over a median follow-up of 47 months (range, 2-115 months). Overall survival was 77%. Conclusions: Gore-Tex/Marlex composite patch repair of large CDHs in this complex patient population results in a lower recurrence rate than has been reported for other types of prosthetic diaphragm repair. [Copyright &y& Elsevier]

Abstract: Within the scope of linear elasticity, an in-plane problem related to the repair of an infinite thin elastic plate with a hole by a patch is considered. The patch and the plate are joined together only along their boundaries. The plate is subjected to stresses applied at infinity. The problem is reduced to a system of four singular integral equations. Existence and uniqueness of the solution of the system is proved. The proposed solution allows one to evaluate the efficiency of a patch repair with little computational effort. [Copyright &y& Elsevier]

Abstract: The problem of improving fracture and/or fatigue life of structural components by means of patch repairs is addressed in the present paper by applying a biology-based method, known as the Genetic Algorithm. The optimum design procedure consists in evaluating the patch topology, to be applied to the highest stressed region, which maximises the fracture resistance or the expected fatigue life of the improved structural component by keeping constant the total patched area (constrained optimisation problem). The proposed procedure is implemented in a finite element code and some numerical simulations are carried out in order to assess its reliability. The method is applied to two simple cases of cracked plates under pure Mode I or Mode II: for such analysed configurations, the method allow to improve significantly the fracture or fatigue behaviour of structural components repaired by employing the optimised shape patches instead of a simple shape (e.g. square or rectangular) patches. [Copyright &y& Elsevier]

Abstract: The problem of the optimal shape of patch repairs for cracked plates is here examined by applying a biology-based method, known as the genetic algorithm. The optimum design procedure consists in evaluating the patch topology which maximises or minimises some mechanical properties of the repaired plate while keeping constant the total patched area (constrained optimisation problem). In the present paper, the best patch shape is determined by minimising the stress-intensity factor function (which is the adopted objective function). The proposed procedure is implemented in a finite element code, and some numerical simulations are carried out in order to assess the reliability of the method when applied to the case of a cracked plate under Mode I. For some configurations analysed, the stress-intensity factor can significantly be reduced by employing an optimal shape patch instead of a simple shape (square or rectangular) patch. [Copyright &y& Elsevier]

Abstract: Experimental investigation is conducted to assess structurally the effectiveness of patch repair in axially loaded columns. Two patch repair materials are selected with high and low modulus of elasticity. The concrete columns were patch repaired under loaded and unloaded conditions. The patch repair is structurally effective for concrete columns repaired in an unloaded state. While for concrete columns repaired in a loaded state, the patch repair is structurally effective only when additional loading is applied. The load distribution between the patch repair, concrete core and steel reinforcement depends on the modulus of elasticity and areas of these components in the composite section at the repaired zone. For patch repair to be structurally effective, it is recommended to relieve the loads before the patch repair is applied either partially or totally if constructionally possible. [Copyright &y& Elsevier]

Abstract: Patch repair is commonly used to rectify localized corrosion induced damage in concrete structures. However, inadequate durability in patch repair systems caused by new corrosion attack is prevalent. From the prevailing understanding, the mechanism is attributed to macrocell corrosion formed between repaired area (called patch) and its adjacent unrepaired area (called substrate), and thereby ensuring electrochemical compatibility between the two areas is deemed to be the key element to reduce the corrosion risk and thus to achieve a successful repair. This paper examined the corrosion mechanism and the concept of compatibility in patch repair systems from fundamental electrochemical principles and experimental verification. It was illustrated that both macrocell and microcell corrosion mechanisms could play significant roles, and the total corrosion could be underestimated if the latter is overlooked. Although the incompatibility serves as the driving force for the macrocell corrosion, in light of corrosion kinetics, it was shown that the corrosion magnitude depends more on the individual corrosion kinetics of the anode or cathode. [Copyright &y& Elsevier]

Abstract: Fatigue crack growth behavior in a stiffened thin 2024-T3 aluminum panel repaired with one-sided adhesively bonded composite patch was investigated through experiments and analyses. The patch had three plies of unidirectional boron/epoxy composite. 2024-T3 aluminum stiffeners were riveted as well as bonded on the panel. Stiffeners were oriented in the loading direction and were spaced at either 102mm or 152mm with a crack centered between them. Also, un-repaired cracked panel with and without stiffeners were studied. Experiment involved tension–tension fatigue at constant amplitude with maximum stress of 120MPa and stress ratio of 0.05. Bonded composite patch repair increased fatigue life about five-fold in the case of stiffened panels while it increased about ten fold in the case of un-stiffened panels. Fatigue life also increased with decrease of the distance between the stiffeners for both repaired and un-repaired panels. A three-dimensional finite element method was used to analyze the experiments. Residual thermal stresses, developed during patch bonding, requires the knowledge of temperature at which adhesive becomes effective in creating a bond between the structure and patch in the analysis. A simple method to estimate the effective curing temperature range is suggested in this study. The computed stress intensity factor versus measured crack growth relationships for all panel configurations were consistent and in agreement with the counterpart from the test material. Thus, the present approach provides a means to analyze the fatigue crack growth behavior of stiffened structures repaired with adhesively bonded composite patch. [Copyright &y& Elsevier]

Corrosion of concrete reinforcement at a patch repair is a complex problem, and current knowledge of its mechanism is quite limited. This review examined the correlation between two corrosion mechanisms, macrocell and microcell corrosion, from fundamental electrochemical principles. It was found that both mechanisms could play significant roles in inducing corrosion damage, contrary to the prevailing opinion that macrocell corrosion is the main deterioration mechanism in patch repair. This has practical implications that need to be considered for an effective and durable repair. A review of the studies done to date also enabled the identification of the key factors in patch repair controlling the corrosion characteristics. Corrosion could occur at different locations in the vicinity of the patch — substrate, interface, or patch area — depending on the respective electrochemical environments induced by the repair material properties and treatments, as well as the in-service exposure and mechanical loading. The review indicates that much of the needed research should focus on identification of corrosion mechanisms to effect successful patch repair in reinforced concrete structures. [ABSTRACT FROM AUTHOR]

Annular subvalvular left ventricular aneurysm was first reported in 1962. This type of aneurysm usually arises from the annular subaortic or submitral region of the left ventricle. It should be differentiated from the left ventricular false aneurysm, which was caused by myocardial necrosis. The etiology of subvalvular aneurysm remains unclear. We have presented a case of annular submitral left ventricular aneurysm. The patient had no history of coronary artery disease. Two-dimensional echocardiography and magnetic resonance image (MRI) showed a huge left ventricular aneurysm existed. An annular submitral left ventricular aneurysm was confirmed by an open heart surgery and pathological examination.(ECHOCARDIOGRAPHY, Volume 22, May 2005) [ABSTRACT FROM AUTHOR]

Abstract: Objective: Controversy still exists regarding the optimal surgical technique for postinfarction left ventricular (LV) aneurysm repair. We analyze the efficacy of two established techniques, linear vs. patch remodeling, for repair of dyskinetic LV aneurysms. Methods: Between May 1988 and December 2001, 110 consecutive patients underwent repair of LV aneurysms. These represent 2.0% of a total group of 5429 patients who underwent isolated CABG during the period. Seventy-six (69.1%) patients were submitted to linear repair and 34 (30.9%) to patch remodelling. There were 94 (84.5%) men and 17 women, with a mean age of 59.2±9.2 years. Coronary surgery was performed in all patients (mean no. of grafts/patient, 2.7±0.8) and 14 (12.7%) had associated coronary endarterectomy. Forty-four (40.0%) patients had angina CCS class III/IV (linear 43.4%, patch 32.4%, NS) and the majority was in NYHA class I/II (88.2% in both groups). Left ventricular dysfunction (EF>40%) was present in 72 (65.5%) patients (linear 61.8%, patch 73.5%, NS). Results: There was no perioperative mortality, and major morbidity was not significantly different between linear repair and patch repair groups. During a mean follow-up of 7.3±3.4 years (range 4–182 months) 14 patients (14.3%) had died, 12 (85.7%) of possible cardiac-related cause. Actual global survival rate was 85.7%. Actuarial survival rates at 5, 10 and 15 years were 91.3, 81.4 and 74%, respectively. There was no significant difference in late survival between the patch and the linear groups. At late follow-up the mean angina and NYHA class were, 1.3 (preoperative 2.4, P&#60;0.001) and 1.5 (preoperative 1.7, NS), respectively, with no difference between the groups. There was no significant difference in hospital readmissions for cardiac causes (linear 22.8% and patch 37.0%). Conclusions: The technique of repair of postinfarction dyskinetic LV aneurysms should be adapted in each patient to the cavity size and shape, and the dimension of the scar. Both techniques achieved good results with respect to perioperative mortality, late functional status and survival. [Copyright &y& Elsevier]

The most popular techniques for repairing large diaphragmatic defects involve the use of synthetic patches. We present an alternative approach using living tissue. We reviewed our cases of congenital diaphragmatic hernia (CDH) diagnosed within the first 24 h of life from 1991 to 2003. Toldt's fascia (TF) flap was used to repair defects that were too large to repair primarily even though the anterior rim of the diaphragm was present. After confirming that a small medial muscle remnant of the diaphragm was present, its mesothelial covering was incised, and the incision was extended to the TF far enough to create a flap sufficiently large to repair the defect. The TF flap, consisting of the small medial muscle remnant, TF, peritoneum, and retroperitoneal connective tissue, was mobilized carefully from the ipsilateral kidney and adrenal gland, and the repair completed with interrupted sutures using nonabsorbable material. We used this TF flap approach in seven of 43 patients with CDH. Two had right-sided CDH. Six survived. The mean size of the diaphragmatic defects in the seven TF flap cases was 5.43+/-0.53 x 3.86+/-1.07 cm, which was significantly larger than the defects in direct primary repair cases (3.40+/-0.77 x 2.03+/-0.59 cm) (p<0.01). The six survivors had good outcomes, and none of them have had recurrence of herniation or required any additional surgical intervention (mean follow-up period: 4.7 years). To the best of our knowledge, this is the first report of TF being used to repair large diaphragmatic hernias. Our technique is simple and has proven to be reliable for durable restoration of the diaphragm, suggesting that it could reduce the dependence on synthetic patch repair, which is associated with certain long-term complications. [ABSTRACT FROM AUTHOR]

Adhesively bonded composite patch repair has been widely used to restore or extend the service life of cracked structural components due to its efficiency and cost-effectiveness compared to mechanical repair technique. Current available knowledge on patch repair mainly focus on flat damaged structures and the corresponding analysis methods and empirical databases are computationally efficient. In contrast, only limited work has contributed to studying patch repair to curved damaged structures. Authors have developed an adhesive element in conjunction with a shell element to investigate the effect of curvature on the adhesive stresses and mode I fracture toughness of the cracked host shell in the curved repairs. In this paper, this technology is again employed to model an adhesively bonded composite patch repair to a cylindrical shell embedded with an inclined through-thickness crack. The total strain energy release rate (SERR), calculated by the modified virtual crack closure technique (VCCT), is used to evaluate the mix-mode fracture toughness of the damaged structure and further to estimate the efficiency of patch repair. An automatic mesh generation scheme is proposed to conduct a quick parametric analysis, which can also be used to structural optimization design of composite patch repair. The numerical results are presented to show the effect of curvature and inclined angle of the through-thickness crack on fracture toughness of the repaired structure subject to different loads. [Copyright &y& Elsevier]

The increasing use of composite material leads to the question of appropriate maintenance and repair techniques for composite structures. A preferred repair technique applies adhesively bonded patches, after the damaged laminate material has been removed by cutting or drilling a hole. In the present paper within the scope of classical laminate theory, the problem of a laminate plate with an elliptical hole repaired by elliptical patches under in-plane and/or bending load is investigated. For the considered base plate and repair patch arbitrary bending extension coupling is allowed. There are no restrictions for the elastic membrane and bending stiffnesses of the underlying layups. With regard to the hole and patch design any size of the elliptical shape is admitted. The analysis of the repair problem is performed by the complex potential method. The complex potentials are defined by appropriate series representations for the base plate, the repair region and the hole domain. The derived closed-form analytical solution provides all essential field quantities for an accurate and effective assessment of the external patch repair. [Copyright &y& Elsevier]

Background: This study reviewed our experience with laparoscopic ventral postoperative (incisional) hernia repair.Methods: Clinical data from the first 100 cases were analyzed retrospectively.Results: Between 1997 and 2000, 64 women and 36 men (mean age, 58.4 +/- 13.6 years; range, 27-87 years) underwent laparoscopic hernioplasty. Hernias (mean diameter, 6.2 +/- 3.7 cm) were in a midline (74%), subcostal (10%), or other incision location, and were recurrent in 25%, of the patients. The mean operative time was 119 +/- 77 min. Extensive adhesiolysis was necessary in 37 cases. There was no mortality. The recorded complications included inadvertent enterotomies (n = 6), seromas (n = 11), prolonged ileus (n = 4), and prolonged fever (n = 3). Seven cases were converted; to repair accidental enterotomies (n = 4) due to difficult adhesiolysis (n = 2), or to control bleeding (n = 1). Six patients underwent reoperation because of enetric leak (n = 3) or bowel obstruction (n = 3). There were two documented recurrences (2%). The mean follow-up period was 19 months (range, 12-54 months).Conclusions: Laparoscopic intraperitoneal approach to postoperative ventral (incisional) hernia repair may be associated with significant complications and morbidity, which can be prevented in part by meticulous technique and liberal conversions. The justification of this procedure is the low recurrence rate, according to preliminary results. [ABSTRACT FROM AUTHOR]

Fatigue response of cracked aluminum panels repaired with a single-sided composite patch is examined. Fatigue tests were carried out under various temperature and humidity conditions. From the experimental results of fatigue tests, the repair efficiency for single-sided composite patches bonded to cracked aluminum panels is evaluated using the range of stress intensity at crack tip. The effect of temperature on the repair efficiency can be found by comparing the results of crack growth at 353 K, 300 K and 223 K. Likewise, the effect of humidity on their repair efficiency can be found by comparing the results of crack growth at 90%, 50% and 25% relative humidity. Other factors that reduce the repair efficiency are also discussed. [ABSTRACT FROM AUTHOR]

Crack growth of cracked aluminum panels repaired with a bonded composite patch is analyzed to evaluate the effect of repair. An efficient finite element analysis using Mindlin plate elements is developed. The technique is extended to a three-layer model, which consists of patch, adhesive and plate layers. The crack growth behavior of an aluminum panel with the composite patch is discussed on the basis of the Paris relation. [ABSTRACT FROM AUTHOR]

Retroviral particles contain a diploid RNA genome which serves as template for the synthesis of double-stranded DNA in a complex process guided by virus-encoded reverse transcriptase. The dimeric nature of the genome allows the proceeding polymerase to switch templates during copying of the copackaged RNA molecules, leading to the generation of recombinant proviruses that harbor genetic information derived from both parental RNAs. Template switching abilities of reverse transcriptase facilitate the development of mosaic retroviruses with altered functional properties and thereby contribute to the restoration and evolution of retroviruses facing altering selective forces of their environment. This review focuses on the genetic patchwork of retroviruses and how mixing of sequence patches by recombination may lead to repair in terms of re-established replication and facilitate increased viral fitness, enhanced pathogenic potential, and altered virus tropisms. Endogenous retroelements represent an affluent source of functional viral sequences which may hitchhike with virions and serve as sequence donors in patch repair. We describe here the involvement of endogenous viruses in genetic reassortment and patch repair and review important examples derived from cell culture and animal studies. Moreover, we discuss how the patch repair phenomenon may challenge both safe usage of retrovirus-based gene vehicles in human gene therapy and the use of animal organs as xenografts in humans. Finally, the ongoing mixing of distinct human immunodeficiency virus strains and its implications for antiviral treatment is discussed.Copyright © 2000 National Science Council, ROC and S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background Perforated peptic ulcer (PPU) is a relatively uncommon condition in children. We aim to evaluate and compare the outcomes of laparoscopic omental patch repair versus open repair for PPU in pediatric patients. Methods Children who underwent omental patch repair for PPU from 2004 to 2014 in our hospital were reviewed retrospectively. Patient demographics, perioperative as well as intraoperative details and surgical outcomes, were analyzed. Results Thirteen patients were identified, and all presented with abdominal pain. The median age of the study group was 14.9 years (range 6.3 to 18.4 years). Radiological evidence of pneumoperitoneum on erect chest x-ray (CXR) was found only in five patients (38.5%). None of the patients had a known history of peptic ulcer disease. Diagnosis other than PPU was made in five patients preoperatively. Laparoscopic repair was attempted in eight patients with one of them requiring conversion. There was no significant difference in patient demographics when compared with the open repair group. The perforation site was in the duodenum in 11 patients and in the antrum in two patients. The mean size of perforation was larger in the open repair group (p = 0.005). Although the operating time was longer in the laparoscopic group (p = 0.51), the length of hospital stay was significantly shorter (p = 0.048). Only two patient diseases were Helicobacter pylori related. Conclusion Clinical features of perforated peptic ulcer in children are different from adults. Risk factors are less frequently identified. Laparoscopic omental patch repair is a feasible surgical option and is associated with satisfactory outcomes in pediatric practice. [ABSTRACT FROM AUTHOR]