Technique of renal biopsy by ultrasound guided percutaneous puncture with a spring loaded "gun".

The study consisted of 89 consecutive patients (mean age = 41.5, range = 16-82, 64 men, 25 women) referred for renal biopsy because of clinical suspicion of renal parenchymal disease. Neither transplant kidneys nor tumour evaluation were included. A biopsy "gun" (Biopty) and 14 (2.0 mm) and 18 (1.2 mm) gauge needles were used with ultrasound guidance. Sixtyseven renal biopsies were guided using a freehand technique 42 using a fixed angle guide attachment. The mean glomerular yield was 9.4 glomeruli. Almost 25% of the 18 gauge needle biopsies (n = 57) had to be repeated and 29.3% of the 14 gauge needle biopsies (n = 75). The yield difference was not statistically significant (Chi-squared = 0.37, p = 0.54). There was no statistically significant difference between the distributions of failure to obtain a significant material for evaluation caused by the biopsy technique used (Chi-squared = 0.08, p = 0.78). When analysing cases of single successful pass the thinner needle produced 6.7 glomeruli (n = 36, SD = 5.08) and the thicker needle 13.8 glomeruli (n = 18, SD = 6.82). No serious complications occurred.