A New Stapes-Head Coupler for the Vibrant Soundbridge System.

INTRODUCTION: The Vibrant Soundbridge (MED-EL Medical Electronics, Austria) is an active middle ear implant with a floating mass transducer (FMT) for patients with conductive, sensorineural, or mixed hearing loss. While the FMT is vertically aligned above the stapes head (SH) with the current Vibroplasty Clip coupler (MED-EL Medical Electronics), the new SH coupler was developed to mount the FMT on the inferior side of the stapes and to fit in the reduced middle ear space after canal-wall-down mastoidectomy. METHODS: Using 11 human cadaveric temporal bones (TBs), placements of the new SH couplers on the stapes were examined, and effective stimuli to the cochlea were evaluated by measuring piston-like motion of the stapes footplate with a current of 1 mA on the FMT. The results were assessed in comparison with the Vibroplasty Clip coupler. RESULTS: The new SH coupler showed perfect coupling on the stapes in 9 out of 11 TBs. A small gap between the SH and the plate of the connection link part was unavoidable in 2 TBs but had negligible effect on vibrational motion of the stapes. Vibrational motion of the stapes with the new SH coupler was reduced at frequencies above 3 kHz compared to the corresponding motion with the current Vibroplasty Clip coupler, but the relative attenuation over all 11 cadaveric temporal bones was <10 dB. CONCLUSIONS: The new SH coupler provides an alternative with more stable fixation when placement of the current Vibroplasty Clip coupler is limited due to insufficient space after canal-wall-down mastoidectomy, while still delivering effective stimuli to the cochlea.

[Treatment of iron deficiency by a bolus intravenous iron dextran in peritoneal dialysis]. / Traitement de la carence martiale par injection d'une dose totale de fer dextran en dialyse péritonéale.

INTRODUCTION: The main objective of this study is to determine whether a single dose of iron dextran can correct iron deficiency during a period of four months in peritoneal dialysis patients. METHOD: This was a prospective observational study in peritoneal dialysis patients who had anemia (hemoglobin<11g/dL) and iron deficiency (ferritin<100µg/L and/or transferrin saturation<20%). Patients who were resistant to oral iron or who could not tolerate oral iron were included in the study. At baseline, based on the iron deficiency estimation, a single dose of iron dextran was infused over four hours. RESULTS: Of 17 patients included, 12 completed the study. The mean iron dose infused was 742±150mg. No clinically significant adverse event was reported during the infusion. Four months after the iron dextran infusion there was a significant increase of the mean hemoglobin level (10.1±0.7g/dl vs 11.4±1.2g/dL, P<0.05), the mean blood ferritin level (66±46mg/L vs 212±121mg/L, P<0.05) and the mean transferrin saturation (14±5% vs 23±8, P<0.05). Four months after the iron infusion 10 patients had a blood ferritin level higher than 100µg/L and a transferrin saturation higher than 20%. There was no significant modification of the erythropoietin dose during the four months period. CONCLUSION: In patients treated by peritoneal dialysis, the anemia due to iron deficiency can be treated by a single infusion of iron dextran for a period of four months.