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International audience; We report a bending-insensitive multi-core fiber (MCF) for lensless endoscopy imaging with modified fiber geometry that enables optimal light coupling in and out of the individual cores. In a previously reported bending insensitive MCF (twisted MCF), the cores are twisted along the length of the MCF allowing for the development of flexible thin imaging endoscopes with potential applications in dynamic and freely moving experiments. However, for such twisted MCFs the cores are seen to have an optimum coupling angle which is proportional to their radial distance from the center of the MCF. This brings coupling complexity and potentially degrades the endoscope imaging capabilities. In this study, we demonstrate that by introducing a small section (1 cm) at two ends of the MCF, where all the cores are straight and parallel to the optical axis one can rectify the above coupling and output light issues of the twisted MCF, enabling the development of bend-insensitive lensless endoscopes.

International audience

Background Percutaneous radiofrequency‐assisted liver partition with portal vein embolization in staged liver resection (PRALPPS) represents an alternative to portal vein embolization (PVE) followed by major liver resection in patients with perihilar cholangiocarcinoma. Methods This was an observational case–control study. Both procedures were applied in patients with a future liver remnant (FLR) volume of less than 40 per cent. The main end points of the study were short‐term morbidity and mortality for the two procedures. The study also compared the efficacy of the preresection phases estimated by kinetic growth rate (KGR), time interval and degree of hypertrophy of the FLR. Results The first phase (preresection) was completed in 11 and 18 patients, and the second phase (resection) in nine and 14 patients, in the PRALPPS and PVE groups respectively. Major morbidity after the first stage did not differ between the groups. There were no differences in blood loss, severe morbidity or liver failure rate after the second stage, with no deaths. The mean KGR of the FLR after the preresection phase for PRALPPS was 3·8 (0·6–9·8) per cent/day, and that after PVE was 1·8 (0–6·7) per cent/day (P = 0·037). The mean time interval for FLR hypertrophy in the PRALPPS and PVE groups was 15 (6–29) and 20 (8–35) days respectively (P = 0·039). Conclusion Short‐term outcomes were similar for PRALPPS and PVE in terms of safety. Remnant hypertrophy was achieved more rapidly by PRALPPS., Percutaneous radiofrequency‐assisted liver partition with portal vein embolization in staged liver resection (PRALPPS), modIfied ALPPS with reduced surgical trauma on the first stage, was used in 11 patients with perihilar cholangiocarcinoma. PRALPPS did not differ from portal vein embolization (PVE) in terms of morbidity or mortality. The kinetic growth rate and mean time interval for future liver remnant hypertrophy in the PRALPPS group were significantly better than those in the PVE group. Similar complication rates and outcomes