34 research outputs found

    Uveal melanoma: Therapeutic consequences of doubling times and irradiation results; a review

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    Abstract Thirty-six of 39 published calculated doubling times (Td's) of uveal melanomas appeared to be longer than 60 days. Metastatic death occurs 35–40 Td's after dissemination. The shortest interval between dissemination and metastatic death in individual patients may, therefore, be calculated as 35×60 days=6 years; the interval may extend to 80 years. This suggests, that local therapy cannot influence the survival data within the first 7 post-therapeutic years, because almost all metastatic deaths within these 7 years are due to pretreatment dissemination. For that reason, the published comparative survival analyses after various therapies have within this period failed to show statistically significant death rates differences. Microscopically viable melanoma tissue has been noted in 215 of 231 histopathologically studied irradiated uveal melanomas. Observed mitotic figures 4–6 years after irradiation indicate retained reproductive integrity. This constitutes a — by enucleation avoidable — incremental risk for post-irradiation exponential growth and dissemination. The risk cannot become statistically manifest before a≥10-year follow-up period. Retained, generally poor, visual acuity in a small percentage of patients cannot balance the incremental risk/benefit ratio of irradiation. A few, at present justifiable, indications for radiotherapy on uveal melanomas are enumerated

    Comparison of laser Doppler flowmetry and thermometry in the postoperative monitoring of replantations

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    Reliable postoperative monitoring in microvascular surgery is necessary to improve the success rate of reexplorations following vascular compromise. Surface thermometry is known as an easy and inexpensive objective postoperative monitor and therefore is used by many microsurgeons. Reliability, however, is not satisfactory, and therefore several other instrumental methods have been tested of which laser Doppler flowmetry shows the most promising results. This study compared laser Doppler flowmetry to thermometry in the postoperative monitoring after replantation surgery. In 34 patients, 45 replantations and revascularizations were monitored by laser Doppler flowmetry and thermometry. A reliable alarm value of 10 PU was defined for replantations and revascularizations, with a sensitivity of 93% and a specificity of 94%. Thermometry showed a sensitivity of 84% and a specificity of 86% at 29°C

    Lof der Biostatistiek

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