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

The use of an automated biopsy system for renal biopsy has recently gained popularity, but its safety in single functioning kidneys is unclear.

To report our experience with the automated system for closed renal biopsy during a 5 year period.

Eighty-five patients underwent percutaneous native renal biopsy with the automated biopsy gun (16G needle) under real-time 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).

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.

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.