Using the automated biopsy gun with real-time ultrasound for native renal biopsy

Background: The use of an automated biopsy system for renal biopsy has recently gained popularity, but its safety in single functioning kidneys is unclear. Objective: To report our experience with the automated system for closed renal biopsy during a 5 year period. Methods: Eighty-five patients underwent percutaneus native renal biopsy with the automated biopsy gun (16G needle) under realtime ultrasound. They were chronologically divided into two groups: 41 patients (group A), using an older ultrasound machine; and 44 patients (group B), using a newer ultrasound machine. Nine patients biopsied with a manual 14G Tru-cut needle served as the control (group C). Results: The number of "attempted" passes at the kidney was 4.0 ± 0.1 in group B, 4.7 ± 0.3 in group A (P < 0.05 vs. group B), and 5.8 ± 0.5 in group C (P < 0.01 vs. group B). The number of successful passes did not differ (3.3 ± 0.1, 3.3 ± 0.1, 3.1 ± 0.2). The ratio of "attempted/successful" was 1.28 ± 0.07 in group B, 1.95 ± 0.38 in A, and 1.90 ± 0.21 in C (P < 0.01 vs. B). The number of glomeruli obtained was similar in the three groups. Adequate tissue was obtained in 95%, 98%, and 100%, respectively. Hemoglobin decreased by 4.3 ± 1.1% in group B, 6.9 ± 1.3% in group A, and 11.3 ± 1.8% in group C (P < 0.05 vs. B). Perinephric/subcapsular hematoma occurred in 5 patients (11.4%) in group A (2 taking aspirin), in 2 patients (4.9%) in group B, and in none in group C. The necessity for blood transfusion post-biopsy was similar in all groups. Four of five patients with single functioning kidneys (one in group A and four in group B) had uneventful biopsies, and adequate tissue was obtained in three. Conclusions: The use of the automated biopsy gun is effective, safe and has a low rate of major complications. It may be used safely in single functioning kidneys.