Small renal tumors are increasingly diagnosed and are frequently treated by nephron-sparing surgery. Tumors can be ablated by radiofrequency (RF) energy, which allows the operator to create very localized necrotic lesions. Radiofrequency interstitial tumor ablation (RITA) has been used in human kidneys in an ex vivo experiment to assess the necrotic lesions produced in a model close to physiologic conditions and then in three patients with localized renal cancer prior to radical nephrectomy. In the ex vivo model, four freshly removed kidneys were treated. Bipolar RF energy was delivered by a generator connected to two needles introduced parallel to each other into the renal parenchyma. A thermocouple was inserted between the two active electrodes. The renal artery at physiologic conditions was maintained at a constant temperature of perfusion of 37 degrees C by a computer-assisted Hot-line monitor. Two lesions were produced in each pole of each kidney including the cortex and the medulla. In an initial human study focusing on safety, feasibility, and pathology, three patients were treated by RITA with bipolar and monopolar energy. One patient with a peripheral 2-cm upper-pole tumor was treated percutaneously under ultrasound guidance with local anesthesia only 1 week prior to surgery. The other patients, with 3- and 5-cm tumors, were treated during surgery under general anesthesia just before nephrectomy. Ex vivo, the maximum temperature at the active needles ranged from 84 degrees C to 130 degrees C with 10 to 14 W applied during 10 to 14 minutes. Lesions were on average 2.2 x 3 x 2.5 cm.3 Microscopic examination showed stromal edema with intensive pyknosis. No damage was seen to adjacent untreated tissue. In the in vivo procedure, tolerance of RTA as an anesthesia-free procedure was excellent. The size of the observed lesions was comparable to the forecast size depending on the needle deployment. No side effects were noted, and no adjacent structures were affected by the RF ablation. These preliminary studies demonstrate the ability of RITA to produce localized extensive necrosis in kidney parenchyma and tumors safely under local anesthesia. Further studies could evaluate this new minimally invasive treatment in small kidney tumors considered for nephron-sparing surgery.

Research question Does Pfizer's Covid-19 vaccination detrimentally affect semen analysis parameters? Design We conducted a prospective cohort study in a single large tertiary center in Israel between February and March of 2021. Semen samples of 75 fertile men were analyzed 1-2 months following the second dose of Pfizer's covid-19 vaccine. The semen parameters were compared to the WHO reference ranges. The primary outcome was the percentage of abnormal semen parameters in those vaccinated, i.e. the rates of oligozoospermia, reduced percentage of motile sperm and abnormal sperm morphology. Results The interval from the time of the second vaccine to the date of participation was on average 37 days, with most subjects describing either mild or no side effects after the first or second dose. The mean sperm concentration was 63.2±33.6 10^6 ml with only a single subject (1.3%) with sperm count of 12.5 10^6 ml, considered by the WHO as oligozoospermic. The mean sperm motility percentage was 64.5%±16.7 with only a single subject (1.3%) displaying reduced motility. No significant morphological abnormalities were observed. This constituted a significantly lower percentage of abnormal semen parameters compared with the 5% rates reported in fertile men by the WHO. Conclusions The semen parameters following Covid-19 vaccination were predominantly within normal reference ranges as set by the WHO and do not reflect any causative detrimental effect from COVID-19 vaccination. Our results strengthen the notion that the Pfizer's SARS-CoV-2 vaccine is safe and should be recommended to fertility seeking men. ClinicalTrials.gov number, NCT04778033.

No abstract