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Tissue expander and implant (TE/I) breast reconstruction has been increasing recently. In TE/I breast reconstruction, infection leads to reconstruction failure and is the most serious complication. The infection rate was reported to be higher during the tissue expander period than the implant period. However, few studies have investigated the risk factors for infection during tissue expansion following TE/I breast reconstruction. The goal of this study was to identify risk factors for infection during tissue expansion in TE/I breast reconstruction and to develop a simple risk scoring tool for infection that can be used for clinical application. In this retrospective cohort study, 981 patients who received TE/I breast reconstruction were surveyed and analyzed at one of the main clinics performing TE/I breast reconstruction in Japan. Numerous potential risk factors were collected from the clinical charts. Multiple logistic regression analyses were used to identify risk factors for infection. To develop a risk scoring tool, we converted the coefficients of the identified predictors estimated in the multiple logistic regression analyses into simplified risk scores. We assessed the tool discrimination by drawing a receiver operating characteristic curve and calculating the area under the curve. Infection was noted in 47 patients (4.79%) during tissue expansion. In multiple logistic regression analyses, diabetes, repeated expander insertions, larger expander size (≥400 cc), postoperative hormone therapy before silicone implant surgery, preoperative chemotherapy, and nipple-sparing mastectomy were identified as risk factors for infection during expansion. The area under the curve of the risk scoring tool for infection was 0.734 (95% CI: 0.662-0.807). We have revealed risk factors and proposed a risk scoring tool for infection during tissue expansion in TE/I breast reconstruction. This study may contribute to the prevention and prediction of infection., (© 2013 Wiley Periodicals, Inc.)

Calcium hydroxyapatite ceramics (CHA) are nontoxic materials, provoke little reaction from tissues, and by virtue of these properties represent a good starting point for creating bone substitutes. Although several porous CHAs have been used clinically, there have been few reports that CHA is fully replaced by newly formed bone, which may be due to its structure and the limited connectivity between pores. We recently developed a fully interconnected porous CHA (IP-CHA) by adopting a "foam-gel" technique. Structural analysis by scanning electron microscopy revealed that IP-CHA had spherical pores of uniform size that were interconnected by window-like holes. The surface of the wall structure was smooth, and hydroxyapatite particles were bound tightly to one another. Most of the interpore connections of IP-CHA ranged from 10 to 80 microm in diameter (average, 40 microm). When the cylindrical IP-CHA (diameter, 6 mm; height, 15 mm) was implanted into a rabbit femoral condyle, bone, and bone marrow with abundant vessels formed deep in the pores through the interpore connections. Within a period of 6 weeks, new bone had formed and penetrated to a distance of 3 mm from the surface of the IP-CHA implant. Furthermore, a compression test at 9 weeks revealed that the implanted IP-CHA steadily increased in strength to more than double the value of the initial test. These results indicate that the IP-CHA may have clinical utility as a superior bone substitute., (Copyright 2001 John Wiley & Sons, Inc.)

The viscoelastic property of curdlan solution in dimethyl sulfoxide (DMSO) was investigated. We discuss the difference in the viscoelastic properties of curdlan solution in DMSO and that in 0.1 N NaOH aqueous solution. The viscoelastic function for curdlan solution in 0.1 N NaOH aqueous solution showed the Newtonian flow at the concentration of curdlan as high as 10 wt %. On the other hand, the Newtonian flow was observed in the concentrations below 7 wt % for curdlan solution in DMSO, and the plateau region appeared beyond this concentration. It was revealed by small angle x-ray diffraction measurements that the difference in the mechanical property would be originated from the difference in the network structure. The overlapping concentration c* was calculated on the basis of the mean field theory, and disagreement between theoretical prediction and experimental result was shown. We clarified that the above disagreement can be explained by the polydispersity of the curdlan sample, assuming adequate distribution functions. The static structure of the gel prepared by adding water to curdlan solution in DMSO was investigated. It was clarified by the dynamic viscoelasticity measurement that the cross-linking density increases with increasing the water content., (Copyright 2001 John Wiley & Sons, Inc.)