Background and Objectives: In this in vitro feasibility study we analyzed tissue fusion using bovine serum albumin (BSA) and Indocyanine green (ICG) doped polycaprolactone (PCL) scaffolds in combination with a diode laser as energy source while focusing on the influence of irradiation power and albumin concentration on the resulting tensile strength and induced tissue damage. Materials and Methods: A porous PCL scaffold doped with either 25% or 40% (w/w) of BSA in combination with 0.1% (w/w) ICG was used to fuse rabbit aortas. Soldering energy was delivered through the vessel from the endoluminal side using a continuous wave diode laser at 808 nm via a 400 mm core fiber. Scaffold surface temperatures were analyzed with an infrared camera. Optimum parameters such as irradiation time, radiation power and temperature were determined in view of maximum tensile strength but simultaneously minimum thermally induced tissue damage. Differential scanning calorimetry (DSC) was performed to measure the influence of PCL on the denaturation temperature of BSA. Results: Optimum parameter settings were found to be 60 seconds irradiation time and 1.5 W irradiation power resulting in tensile strengths of around 2,000 mN. Corresponding scaffold surface temperature was 117.4 AE 128C. Comparison of the two BSA concentration revealed that 40% BSA scaffold resulted in significant higher tensile strength compared to the 25%. At optimum parameter settings, thermal damage was restricted to the adventitia and its interface with the outermost layer of the tunica media. The DSC showed two endothermic peaks in BSA containing samples, both strongly depending on the water content and the presence of PCL and/or ICG. Conclusions: Diode laser soldering of vascular tissue using BSA-ICG-PCL-scaffolds leads to strong and reproducible tissue bonds, with vessel damage limited to the adventitia. Higher BSA content results in higher tensile strengths. The DSC-measurements showed that BSA denaturation temperature is lowered by addition of water and/or ICG-PCL. Lasers Surg. Med. 40:716-725, 2008. ß

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Background:The usage of internal mammary artery perforators (IMAPs) has been described in autologous breast reconstruction although IMAPS are not yet considered standard recipient vessels. It remains unclear if these vessels can be safely used in large flaps after radiation therapy or in delayed breast reconstruction.Methods:Over a 2-year period, 515 free flaps for autologous breast reconstruction were performed on 419 patients by 2 surgeons (S1 and S2). In a retrospective analysis, time of reconstruction, ischemia time, flap weight, diameter of couplers, and complications were analyzed. All 515 flaps were compared in a subset with regard to the 2 surgeons: S1 who always used the IMA as a recipient vessel and S2 who attempted IMAP use if possible.Results:Of all 515 flaps, 424 were abdominal flaps and 91 flaps were from the upper thigh. Three hundred six cases were immediate reconstructions, and 112 were delayed reconstructions. In 97 cases, implants were converted to autologous tissue. In 112 cases, the IMAPs were used; of these, 82 were immediate and 17 were delayed reconstructions, and in 13 cases, implants were removed. Thirty-five percent of all anastomoses to IMAPs had previous radiation therapy. The flap failure rate was 1.9%. In none of these cases, the IMAPs were used. S1 never used the IMAP, and S2 used the IMAP in 37% of all of his flaps.Conclusions:IMAPs were safely used in all kinds of reconstructions and after radiation therapy, with no flap failure or negative effects on mastectomy skin flap perfusion. Using the IMAPs as recipient vessels is a further step toward simplifying microsurgical breast reconstruction.