Search

IntroductionCongenital diaphragmatic hernia (CDH) repair is an area of active research. Large defects requiring patches have a hernia recurrence rate of up to 50%. We designed a biodegradable polyurethane (PU)-based elastic patch that matches the mechanical properties of native diaphragm muscle. We compared the PU patch to a non-biodegradable Gore-Tex™ (polytetrafluoroethylene) patch.MethodsThe biodegradable polyurethane was synthesized from polycaprolactone, hexadiisocyanate and putrescine, and then processed into fibrous PU patches by electrospinning. Rats underwent 4 mm diaphragmatic hernia (DH) creation via laparotomy followed by immediate repair with Gore-Tex™ (n = 6) or PU (n = 6) patches. Six rats underwent sham laparotomy without DH creation/repair. Diaphragm function was evaluated by fluoroscopy at 1 and 4 weeks. At 4 weeks, animals underwent gross inspection for recurrence and histologic evaluation for inflammatory reaction to the patch materials.ResultsThere were no hernia recurrences in either cohort. Gore-Tex™ had limited diaphragm rise compared to sham at 4 weeks (1.3 mm vs 2.9 mm, p = 0.003), but no difference was found between PU and sham (1.7 mm vs 2.9 mm, p = 0.09). There were no differences between PU and Gore-Tex™ at any time point. Both patches formed an inflammatory capsule, with similar thicknesses between cohorts on the abdominal (Gore-Tex™ 0.07 mm vs. PU 0.13 mm, p = 0.39) and thoracic (Gore-Tex™ 0.3 mm vs. PU 0.6 mm, p = 0.09) sides.ConclusionThe biodegradable PU patch allowed for similar diaphragmatic excursion compared to control animals. There were similar inflammatory responses to both patches. Further work is needed to evaluate long-term functional outcomes and further optimize the properties of the novel PU patch in vitro and in vivo.Level of evidenceLevel II, Prospective Comparative Study.

Patch repair of deteriorating concrete, which mainly involves the replacement of chloride-contaminated concrete with the fresh alkaline patch concrete is a common intervention to rehabilitate the defecting reinforced concrete (RC) structure while the concrete replacement of this process is expensive. Application of curative corrosion inhibitor directly on the surface of corroding rebar before new patch material casting is recommended as easy to use approach for new corrosion attack. Sacrificial anodes have been used to limit the extension of concrete replacement and extend the service life of patch repair to RC member. This study focuses on the utilization of sacrificial anode cathodic protection arrangement and corrosion inhibitor in partially repair RC beams. Two specimens of 44-years of serious chloride-induced corrosion condition having a length of 2400 mm and 200x300 mm cross-section were prepared as RC-1 and RC-2. The polymer-modified mortar as the patch repair material was applied to the middle tension area in the dimension of 70x150x800mm. Four cylindrical ribbed sacrificial zinc anodes with 30 mm diameter and 130 mm length installed in the parent concrete by LiOH cementitious coating material. A specially modified epoxy paint as corrosion inhibitor was applied to the tensile steel bar surface of the patch repair section in RC-2. The exposure condition of the specimens was on two-days wet and followed by five-days dry in laboratory air condition until 12-months observation. Depolarization test of rebar by the calomel-saturated electrode (CSE) on the side section of specimen’s surface, the current density of sacrificial zinc anodes and rebar, anodic-cathodic polarization curve are measured regularly until 12-months observation as the performance evaluation was presented in this paper. The sacrificial zinc anode tested in this research affects polarizing the potential of rebar in the deteriorated RC member. However, the high polarization is limited to 15 cm aw

Infective endocarditis (IE) remains a prevalent and life-threatening disease. The choice to repair or replace the infected valve still remains a matter of debate, especially in aortic valve (AV) infections. We retrospectively analyze our two decades of experience in aortic valve repair (AVr) in IE. Long-term outcomes are described with particular attention to the impact of valve configuration and the use of patch techniques. From September 1998 to June 2017, 42 patients underwent AVr in a single center for IE. Techniques include leaflet patch repair and resuspension and aortic annulus stabilization. Hospital mortality was 2.4% ( = 1). The median follow-up was 90.6 months. Survival was 89 ± 9.4% and 76.6 ± 16% at 5 and 10 years, respectively, with no significant differences between tricuspid aortic valve (TAV) and bicuspid aortic valve (BAV). Freedom from reoperation was 100% and 92.9 ± 7.1% in TAV and 81.8 ± 18.2% and 46.8 ± 28.8% in BAV at 5 and 10 years, respectively (TAV vs BAV, = 0.02). BAV, degree of preoperative aortic insufficiency, and AVr including patch were factors predicting a higher risk of reoperation during the follow-up. In our experience, AVr is a safe, feasible, and efficient choice in selected patients with healed or active IE. Durability of the repair is excellent in patients with limited lesions and in patients with TAV even with patch repair. Reoperations occurred principally in patients with BAV and severe preoperative AI, in whom patch repair was performed. In those patients, we actually recommend to replace the valve in case of active endocarditis.

PURPOSE: Infective endocarditis (IE) remains a prevalent and life-threatening disease. The choice to repair or replace the infected valve still remains a matter of debate, especially in aortic valve (AV) infections. We retrospectively analyze our two decades of experience in aortic valve repair (AVr) in IE. Long-term outcomes are described with particular attention to the impact of valve configuration and the use of patch techniques. METHODS: From September 1998 to June 2017, 42 patients underwent AVr in a single center for IE. Techniques include leaflet patch repair and resuspension and aortic annulus stabilization. RESULTS: Hospital mortality was 2.4% (n = 1). The median follow-up was 90.6 months. Survival was 89 ± 9.4% and 76.6 ± 16% at 5 and 10 years, respectively, with no significant differences between tricuspid aortic valve (TAV) and bicuspid aortic valve (BAV). Freedom from reoperation was 100% and 92.9 ± 7.1% in TAV and 81.8 ± 18.2% and 46.8 ± 28.8% in BAV at 5 and 10 years, respectively (TAV vs BAV, p = 0.02). BAV, degree of preoperative aortic insufficiency, and AVr including patch were factors predicting a higher risk of reoperation during the follow-up. CONCLUSION: In our experience, AVr is a safe, feasible, and efficient choice in selected patients with healed or active IE. Durability of the repair is excellent in patients with limited lesions and in patients with TAV even with patch repair. Reoperations occurred principally in patients with BAV and severe preoperative AI, in whom patch repair was performed. In those patients, we actually recommend to replace the valve in case of active endocarditis.

Infective endocarditis (IE) remains a prevalent and life-threatening disease. The choice to repair or replace the infected valve still remains a matter of debate, especially in aortic valve (AV) infections. We retrospectively analyze our two decades of experience in aortic valve repair (AVr) in IE. Long-term outcomes are described with particular attention to the impact of valve configuration and the use of patch techniques. From September 1998 to June 2017, 42 patients underwent AVr in a single center for IE. Techniques include leaflet patch repair and resuspension and aortic annulus stabilization. Hospital mortality was 2.4% ( = 1). The median follow-up was 90.6 months. Survival was 89 ± 9.4% and 76.6 ± 16% at 5 and 10 years, respectively, with no significant differences between tricuspid aortic valve (TAV) and bicuspid aortic valve (BAV). Freedom from reoperation was 100% and 92.9 ± 7.1% in TAV and 81.8 ± 18.2% and 46.8 ± 28.8% in BAV at 5 and 10 years, respectively (TAV vs BAV, = 0.02). BAV, degree of preoperative aortic insufficiency, and AVr including patch were factors predicting a higher risk of reoperation during the follow-up. In our experience, AVr is a safe, feasible, and efficient choice in selected patients with healed or active IE. Durability of the repair is excellent in patients with limited lesions and in patients with TAV even with patch repair. Reoperations occurred principally in patients with BAV and severe preoperative AI, in whom patch repair was performed. In those patients, we actually recommend to replace the valve in case of active endocarditis.

OBJECTIVES: We retrospectively analysed our 20-year experience on surgical treatment of native mitral valve (MV) endocarditis in a single institution using an early and repair-oriented surgical approach. METHODS: From August 1991 to December 2015, 192 consecutive patients underwent MV surgery for active endocarditis. Of these, 81% (n = 155) had MV repair while 19% had MV replacement. In-hospital and late outcomes were analysed in the 2 groups and in the subgroups of repair with and without the use of a patch. Study end points were overall survival, MV reoperation and valve-related events. The median follow-up was 122 and 146 months in the repair and replacement groups, respectively. RESULTS: Patients undergoing MV replacement were significantly older with more severe preoperative comorbidities and clinical conditions compared to patients undergoing MV repair (P < 0.05). When the repair and replacement groups were compared, hospital mortality was 11.6% and 29.7%, respectively (P = 0.006); at 15 years, overall survival was 57 ± 6% and 36 ± 12%, respectively (P = 0.03); freedom from MV reoperation was 81 ± 6% and 73 ± 18%, respectively (P = 0.46); linearized rate of recurrent endocarditis was 0.1% and 2.4%, respectively. Fifteen-year freedom from reoperation was 75.4 ± 8.6% vs 92 ± 4.5% in the patch versus no-patch repair subgroups, respectively (P = 0.33). CONCLUSIONS: Active MV endocarditis remains a life-threatening disease. In experienced centres, an early and repair-oriented surgical approach can achieve relatively high reparability rates with good long-term durability of the repair and a very low recurrence rate of endocarditis. Patients could benefit from MV repair even if patch material is necessary to repair the valve.

[EN] This paper describes an experimental study on patch-repaired reinforced concrete columns subjected to axial loads until failure. The behaviour of four series of columns repaired with Class R3 and R4 cement-based mortar was analysed both with and without a bonding agent. The results obtained were compared with control series of undamaged and damaged but unrepaired columns to determine the effectiveness of the repairs and the subsequent improvement in the behaviour of the columns. The results of this study were compared with those of previous work by the authors on the analysis of all-four-side repairs and one-side repairs. The conclusion reached was that patch repairs are highly effective as compared to the other techniques studied and that using Class R3 mortar achieves better results on damaged columns made with low-quality concrete. It was also concluded that applying a bonding agent does not improve the results, although this element was found to be necessary to prevent the premature detachment of the repair when there is a substantial difference between the stiffness of the column concrete and that of the mortar used in the repairs. (C) 2018 Elsevier Ltd. All rights reserved.

[EN] This paper describes an experimental study on patch-repaired reinforced concrete columns subjected to axial loads until failure. The behaviour of four series of columns repaired with Class R3 and R4 cement-based mortar was analysed both with and without a bonding agent. The results obtained were compared with control series of undamaged and damaged but unrepaired columns to determine the effectiveness of the repairs and the subsequent improvement in the behaviour of the columns. The results of this study were compared with those of previous work by the authors on the analysis of all-four-side repairs and one-side repairs. The conclusion reached was that patch repairs are highly effective as compared to the other techniques studied and that using Class R3 mortar achieves better results on damaged columns made with low-quality concrete. It was also concluded that applying a bonding agent does not improve the results, although this element was found to be necessary to prevent the premature detachment of the repair when there is a substantial difference between the stiffness of the column concrete and that of the mortar used in the repairs. (C) 2018 Elsevier Ltd. All rights reserved.

Chloride contamination in reinforced concrete leads to the corrosion of steel bars. Concrete patch repairs are widely practiced as a remedial measure for the mitigation of such corrosion in reinforced concrete structures. The performance of the patch repairs was studied by various researchers in the past. The structural and material aspects of patch repairs have received more attention than the electrochemical consequences of patch repairs in past studies. But electrochemical changes could be the underlying cause for the failure of many patch repairs. This paper reviews the performance of patch repairs from a durability point of view. It covers the formation of incipient anodes, which are the new corrosion sites formed after a patch repair process. The prevailing corrosion mechanism at the incipient anodes is discussed. The performance of patch repairs when modified with corrosion inhibitors and sacrificial anodes is examined. The importance of the selection of repair materials from a durability point is highlighted considering the electrochemical consequences of patch repair.

Chloride contamination in reinforced concrete leads to the corrosion of steel bars. Concrete patch repairs are widely practiced as a remedial measure for the mitigation of such corrosion in reinforced concrete structures. The performance of the patch repairs was studied by various researchers in the past. The structural and material aspects of patch repairs have received more attention than the electrochemical consequences of patch repairs in past studies. But electrochemical changes could be the underlying cause for the failure of many patch repairs. This paper reviews the performance of patch repairs from a durability point of view. It covers the formation of incipient anodes, which are the new corrosion sites formed after a patch repair process. The prevailing corrosion mechanism at the incipient anodes is discussed. The performance of patch repairs when modified with corrosion inhibitors and sacrificial anodes is examined. The importance of the selection of repair materials from a durability point is highlighted considering the electrochemical consequences of patch repair.

The properties of magnesium phosphate cement (MPC) mortars with different magnesium to phosphate (M/P) molar ratios and sand to binder (S/B) weight ratios have been investigated. The experimental results show that both M/P and S/B ratios have large influence on the setting time and mechanical properties of MPC mortars. Therefore, the formulation has to be optimized in terms of the workability, performance, as well as cost consideration. Besides, the bond strength is an important performance index for a patch repair material and hence received particular attention in this study. The test results demonstrate that MPC mortars have superior bond strength to ordinary Portland cement (OPC) mortar/concrete substrate. Finally, the volume stability measurements illustrate that the drying shrinkage of MPC based repair mortars is much less than that of OPC mortar. It is demonstrated that MPC mortar is promising to be utilized in patch repair and maintenance works of concrete. (C) 2009 Elsevier Ltd. All rights reserved.

The properties of magnesium phosphate cement (MPC) mortars with different magnesium to phosphate (M/P) molar ratios and sand to binder (S/B) weight ratios have been investigated. The experimental results show that both M/P and S/B ratios have large influence on the setting time and mechanical properties of MPC mortars. Therefore, the formulation has to be optimized in terms of the workability, performance, as well as cost consideration. Besides, the bond strength is an important performance index for a patch repair material and hence received particular attention in this study. The test results demonstrate that MPC mortars have superior bond strength to ordinary Portland cement (OPC) mortar/concrete substrate. Finally, the volume stability measurements illustrate that the drying shrinkage of MPC based repair mortars is much less than that of OPC mortar. It is demonstrated that MPC mortar is promising to be utilized in patch repair and maintenance works of concrete. (C) 2009 Elsevier Ltd. All rights reserved.

The properties of magnesium phosphate cement (MPC) mortars with different magnesium to phosphate (M/P) molar ratios and sand to binder (S/B) weight ratios have been investigated. The experimental results show that both M/P and S/B ratios have large influence on the setting time and mechanical properties of MPC mortars. Therefore, the formulation has to be optimized in terms of the workability, performance, as well as cost consideration. Besides, the bond strength is an important performance index for a patch repair material and hence received particular attention in this study. The test results demonstrate that MPC mortars have superior bond strength to ordinary Portland cement (OPC) mortar/concrete substrate. Finally, the volume stability measurements illustrate that the drying shrinkage of MPC based repair mortars is much less than that of OPC mortar. It is demonstrated that MPC mortar is promising to be utilized in patch repair and maintenance works of concrete. (C) 2009 Elsevier Ltd. All rights reserved.