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OBJECTIVES: To describe imaging assessment, procedural and follow-up outcome of patients undergoing left atrial appendage (LAA) occlusion (LAAO) using a "sandwich" technique.BACKGROUND: The presence of a LAA with chicken wing morphology constitutes a challenge that sometimes requires specific occlusion strategies like the "sandwich" technique. However, procedural and follow-up data focusing on this implanting strategy is scarce.METHODS: This multicenter study collected individual data from eight centers between 2012 and 2019. Consecutive patients with chicken-wing LAAs defined as an early (90°) who underwent LAAO with Amplatzer devices and using the "sandwich" technique were included in the analysis.RESULTS: Overall, 190 subjects were enrolled in the study. Procedures were done with the Amulet device (85%) and the Amplatzer Cardiac Plug (15%). Successful implantation was achieved in 99.5% with ≤1 partial recapture in 80% of cases. Single (46.2%) and dual antiplatelet therapy (39.4%) were the most used antithrombotic therapies after LAAO. In-hospital major adverse events rate was 1.5% with no deaths. One patient (0.5%) had cardiac tamponade requiring percutaneous drainage. With a mean follow-up of 19.6 ± 14.8 months, the mortality and stroke rates were 7.7%/year and 2.5%/year, respectively. Follow-up transesophageal echocardiography (TEE) at 2-3 months showed device-related thrombosis in 2.8% and peri-device leak ≥3 mm in 1.2% of patients.CONCLUSIONS: In a large series of patients with chicken wing LAA anatomies undergoing LAAO, the use of the "sandwich" technique was feasible and safe. Preprocedural imaging was a key-factor to determine specific measurements.

Background Reconstruction of large, complex abdominal wall hernias is an interesting challenge. Primary closure of those hernias is often not possible. There is little agreement about the most appropriate technique or prosthetic to repair these defects, in spite the fact of the prevalence of ventral hernias. Sometimes despite being contaminated surgical fields, we are often faced to reinforce with bio-prosthetic meshes. The component separation technique (CST) is a practical option; however, recurrence rates remain unacceptably high. In an attempt to reduce recurrences, we frequently added a biologic underlay mesh and a lightweight polypropylene on-lay mesh to the traditional CST. Our objective was to determine biologic mesh practice patterns of reconstructive surgeons with regard to indications, most appropriate technique, choice of prosthetics and experience with complications in order to work those hernias out. Methods Thirty consecutive patients who underwent abdominal wall reconstruction by means of a component separations associated with non-cross-linked porcine dermal scaffolds (NCPDS) or a synthetic tissue scaffold (STS) reinforcement between October 2009 and December 2011 were retrospectively reviewed. Analysis of demographics, indications for NCPDS or STS placement, surgical technique, complications and follow-up data were performed. They underwent a ‘sandwich’ procedure with a biologic underlay mesh and a lightweight polypropylene on-lay mesh added to the traditional CST. We chose NCPDS or STS underlay mesh according to the fact of the presence or absence of a contaminated field. Results A ‘sandwich’ procedure was used for abdominal wall repair in 30 patients. In all of them, NCPDS or STS was positioned using an intraperitoneal technique associated to a lightweight polypropylene on-lay mesh and the CST. At a mean follow-up time of 30.1 months, most patients had successful outcomes. Occurrences included seroma, recurrence and infection. One of our patients died from multi-organ failure unrelated to hernia repair. Conclusions This study shows that complex abdominal wall defects can be successfully reconstructed using a ‘sandwich’ procedure with a low rate of recurrence and occurrences. Moreover, repair of large, complex abdominal wall hernias by CST augmented with a biologic underlay mesh and a lightweight polypropylene on-lay mesh results in lower recurrence rates compared with historical reports of CST alone.

Purpose The aim of this study was to determine the long-term treatment efficacy of glycerine-preserved human amniotic membrane transplantation in patients suffering from corneal ulcers. Methods This was a retrospective, non-controlled, monocentric analysis. Included were patients with corneal ulcers that were non-responsive to ointment or contact lenses and had been treated by amniotic membrane transplantation with either the overlay or sandwich procedure. Analysis parameters were visual acuity before and following treatment, recurrence rate and subjective comfort at the last follow-up. Results Of the 371 amniotic membrane transplantations that were conducted, 135 surgical treatments in 108 patients (51.9% male, 48.1% female; mean age 63.7 years) met the inclusion criteria. In total, 99 overlay and 36 multilayer amniotic membrane transplantations were performed. The follow-up period was 47.5 ± 66.7 weeks (mean ± SD). The recurrence rate at the last follow-up was 47.8% with overlay membranes and 51.8% with the sandwich technique. There was no significant change in best-corrected visual acuity following treatment with overlays (p = 0.219) or sandwich procedure (p = 0.703). At the last follow-up, 72.1% (overlay) and 78.3% (sandwich) of the patients reported either no pain or increased comfort. Conclusion The recurrence rates and changes in visual acuity following overlay or sandwich amniotic membrane transplantation in patients suffering from corneal ulcer were lower than reported elsewhere in the literature. More than half of the patients profited from each of the amniotic membrane transplantation techniques with respect to recurrence and postoperative comfort.

Objectives/Hypothesis: The aim of this article was to describe our surgical technique for the treatment of nasal septal perforations with diameters of 1 to 2 cm. Study Design: Retrospective clinical research. Methods: We reviewed 13 patients with moderate nasal septal perforations (1–2 cm diameter) treated with a sandwich technique (bone or cartilage and quadriceps fascia graft as an interposition graft) by an endoscope-assisted intranasal approach from January 2008 to June 2011. Follow-up periods were 3 months. Results: Thirteen patients were treated with the sandwich technique. Twelve cases (92.3%) were completely healed. One case received incomplete closures without any postoperative symptoms. All patients were found not to have any complications after surgery. Conclusions: The transnasal endoscopic sandwich technique for repairing moderate nasal septal perforation (1–2 cm) has a high success rate and is easy to perform. Laryngoscope, 2012

The rising demand for esthetic restorations has considerably increased the number of direct composite restorations being placed in private practices. While composite resin is often selected primarily for its esthetic qualities, another significant advantage of direct composite restorations is the ability to perform conservative cavity preparations. The traditional configuration used for amalgam restorations is no longer mandatory; thus, more sound tooth structure can be preserved. The technique of composite placement is complex when compared to amalgam placement. The use of adhesive systems prior to placement of composite restorations requires not only excellent isolation to avoid contamination, but also precise manipulation of the adhesive system. While stable bonds to enamel are routinely obtained, the heterogeneous composition and intricate morphology of dentin makes this substrate more challenging to restore. In addition, the cavity configuration (C-factor) and inherent polymerization shrinkage of composite resin play an important role in the durability of the composite–dentin interface. Class II preparations often have gingival margins in root surfaces because of the location of the caries lesion. Clinicians are then faced with a preparation that is challenging to isolate, has a relatively high C-factor, and relies on optimal bonding to dentin to secure long-lasting marginal integrity. Various restorative techniques, such as incremental placement or the use of an intermediate layer (flowable composite or resin-modified glass ionomer cements—open sandwich technique), have been some of the methods proposed to increase the longevity of composite restorations, especially those with margins in dentin. This review evaluates some of the published research on Class II composite resin restorations with margins in the dentin/cementum.

The sandwich technique with resin-modified glass ionomer cement (RMGIC) has been proposed to relieve the contraction stresses of direct resin composite (RC) restorations. The aim of this study was to evaluate the interfacial adaptation to enamel and dentin of modified Class II open RMGIC/RC sandwich restorations and the influence of different light curing techniques and matrix bands. Forty box-shaped Class II fillings were placed in vivo in premolars scheduled for extraction after one month. In groups I and II, a metal matrix was used; RC was inserted with horizontal (group I) and diagonal (group II) increments and cured with indirect/direct light. Group III was performed as group II, but a transparent matrix was used. Group IV was as group II, but with a separating liner between RMGIC and RC. Group V was a closed sandwich restoration. Interfacial quality was studied using SEM replica technique. Gap-free interfacial adaptation to enamel was observed for RMGIC in 70%, for RC in 70% and to dentin for RMGIC in 81%, for RC in 56%. No significant differences were seen between the experimental groups. At the cervical margins, RMGIC showed significantly better adaptation to enamel than RC, 74% and 42%, respectively. In conclusion, the investigated restorations showed a high percentage of gap-free interfacial adaptation in vivo. Interfacial adaptation to dentin and to cervical enamel was significantly better for RMGIC than for RC.

A bond between glass ionomer cements (GIC) and resin composites is desirable for the success of the 'sandwich' restoration. Chemically cured glass ionomer cements have been the traditional materials used in this technique since its development, but etching the GIC was necessary to obtain a bond to the composite facing. Producing a very smooth GIC surface has aided in better determining the magnitude of the chemical bond between glass ionomers and resin composites. Shear testing of bonded specimens has revealed that chemical bonding is minimal (0.21 MPa) in conventional glass ionomers, but does exist (4.92 MPa) between GIC and resin composite regardless of the filler content (microfilled vs hybrid) of the composite. Thermal stressing affects the bond to resin-modified glass ionomers, but has no significant effect on self-cured cements. Of all combinations tested. Vitremer/Scotchbond/Silux Plus showed the highest mean shear bond strength. Based on the clinical need for an adhesive bond between GIC liner/base and resin composite, the resin-modified glass ionomer would appear to be the material of choice.

Summary Serum IgE was estimated in 226 healthy children aged 0–14 years without obvious atopic disease in their first degree relatives. A paper disc radioimmunoassay technique (PRIST) was used. A number of criteria for selection of cases were established. This led to the exclusion of forty-two potentially atopic children. The remaining group of 184 children is considered representative of normal children and may therefore be used for reference purposes. The IgE levels were found to be lower than in previous investigations, and this is attributed to the refined technique and the method of selection.

SUMMARY In the processing of cell cultures, grown as a monolayer in tissue culture dishes for electron microscopy, the sectioning of the monolayer is an essential step. The monolayer can be sectioned either parallel or perpendicular to the plane of growth. Several methods for the perpendicular way of sectioning have already been described. We propose a simplified method in which the monolayer is sandwiched between two layers of resin, one of which is a pre-polymerized block, the other being a layer of resin, applied at a second stage. Sectioning of this ‘flat embedded’ specimen yields thin sections perpendicular to the plane of growth of the monolayer without elaborate orientating procedures. The advantage of this procedure is that it can be done using only routine embedding techniques, avoiding special materials or complex manipulations. This sandwich technique provides an excellent mechanical fixation of the monolayer and protects it against external damage.

A methyl methacrylate composition of exactly zero birefringence has been developed and the technique of its application to the sandwich method with a birefringent layer of Araldite is described in detail with special consideration of the problems of cementing the two different materials. Tensile and bending tests on bars with stress concentrations demonstrate the validity of the method.

Commercial Perspex and “Perspex” of zero birefringence are applied in an investigation by the sandwich technique of the stress in a transverse section of a container from which lead is extruded through a die. The use of commercial Perspex in this application is shown to give rise to errors which are avoided by the new material of zero birefringence. The principal stresses in the birefringent layer of the sandwich are evaluated.

The development of the sandwich technique in photoelasticity necessitates a suitable cement. The results of experiments using cyanoacrylate IS 12 in cementing Perspex and Araldite are compared with the results of experiments using resorcinol formaldehyde. These show that cyanoacry/ate is much superior in strength and that it has other properties suitable for the purpose.