The introduction of renal biopsy into nephrology from 1901 to 1961: a paradigm of the forming of nephrology by technology.

'Biopsy' (Besnier 1895) became useful towards the end of the 19th century with the development of good histology and microbiology. Needle biopsy of the liver, although first performed in 1895, did not become current until 50 years later. Surgical biopsy of the kidney at incidental operations, particularly the then fashionable renal decapsulation, was performed from 1900 to 1930. Percutaneous needle renal biopsy was introduced after first, the successful liver biopsy and second, demonstration of the value of aspiration needle biopsy in tumours of the kidney. In addition, a number of physicians obtained renal tissue by accident and without problems during intended biopsies of the liver. Nils Alwall of Sweden performed the first systematic aspiration needle biopsies of the kidney in 1944, but did not publish his results because of an early death which led him to abandon the technique. However, when Iversen and Brun in Copenhagen described their results in 1951, a number of physicians around the world immediately began to attempt renal biopsy, using cutting as well as aspiration techniques. Success was inconsistent and operator dependent: the refinements of technique and needles introduced by the group in Chicago led by Robert Kark, plus their advocacy of the technique and their training of many physicians in its performance rapidly led to widespread acceptance. New techniques of immunofluorescence and electron microscopy arrived at the same time so that the technique could be fully exploited. The performance and interpretation of renal biopsies became, along with classical whole-organ and nephron physiology and the introduction of dialysis and transplantation, powerful agents determining the emergence of Nephrology as a specialty around 1960.