Data collection
Clinical data collection and intra-operative measurements were performed by the same researcher(EC). Patient demographics, weight, height, body mass index(BMI), and occupational status were recorded. Occupational status was categorized as light workers and heavy workers. Patients that worked in jobs requiring physical strength, such as construction, farming, delivery, were categorized as heavy workers, whereas office employees, housewives, and the unemployed were categorized as light workers.
Surgery was performed by experienced surgeons (FTA, CYB or MSY). All nephrectomies were performed via the transperitoneal approach. In order to record surgical data the researcher in charge (EC) and an observer(FI) were present during all surgical procedures. Perirenal fat dissection time was recorded by a time observer (FI). The complexity of perirenal fat dissection was classified by EC and divided into 3 categories; easy, moderate, and difficult. This classification was based on the difficulty of dissection, capsular trauma during dissection, bleeding, and unintentional injuries during removal of perirenal fat from the kidney. In addition, maximum perirenal fat thickness(mm) and maximum subcutaneous fat thickness(mm) were measured intra-operatively by EC. The removed perirenal fat tissue was sent for histopathological examination after measurement.