Post renal biopsy complication rate and diagnostic yield comparing hands free (ultrasound-assisted) and ultrasound-guided biopsy techniques of renal allografts and native kidneys

BACKGROUND: Real time ultrasound guided percutaneous kidney biopsy has become the standard procedure to assess the pathology of native kidneys and renal transplants. No specific technique has shown to be totally free of post biopsy bleeding complications. Few Studies have looked at the rates of post biopsy bleeding complications comparing different needle size, post biopsy haematoma size, or clinical predictors of the complication rates. In this study we aim to assess safety and adequacy of the real time ultrasound guided biopsy using free hands (ultrasound-assisted) and ultrasound-guided technique. METHOD: The results of 527 elective native and kidney transplant biopsy performed as a day case procedure at Lancashire Teaching Hospitals were retrospectively reviewed (499 native and 28 allograft biopsies). Biopsies were grouped into 4 groups according to the technique and the needle size; group 1 (n = 119; performed by free hands-ultrasound assisted- technique using 14G needle) Group 2 (n = 59; performed by free hands-ultrasound-assisted technique using 16G needle), group 3 (n = 195; performed by ultrasound-guided technique using 14G), and group 4 (n = 154; performed by ultrasound-guided technique using 16G). The 4 groups were matched in age, sex, weight, haemoglobin, serum creatinine, INR, PT, and PTT time. RESULTS: The overall tissue specimen was adequate in 80.45 % of the cases, with no difference between group 1 and 3 (81.5 and 80.52 % respectively, p = 0.82) or between group 2 and 4 (86.44 and 77.3 % respectively, p = 0.13). The overall major complications rate was 2.84 %, with no difference between group 1 and 3 (2.5 and 1 % respectively, p = 0.30) or group 2 and 4 (5 and 4.5 % respectively, p = 0.86). The overall minor complications was 3.7 % with no difference between group 2 and 4 (3.3 and 5.84 % respectively, p = 0.46), however, minor complications were higher in group 1 compared to group 3 (5.8 and 1 % respectively, p = 0.01).There was no difference between using 14G and 16G needle size in terms of tissue adequacy(p = 0.7), major complications (p = 0.2 for drop in Hb >10 g/l, p = 0.08 for blood transfusion, p = 0.35 for embolization) or minor complication items(p = 0.4 for drop in Hb, 10 g/l,p = 0.1 for haematuria, p = 0.7 for hematoma). CONCLUSION: When using a 14G needle, there is higher risk of minor complications in the free hands-(ultrasound-assisted) technique compared to the ultrasound-guided technique. There is no difference in the rates of major or minor complications between free hand and needle-guided technique using 16G needles. Both techniques showed adequate tissue sampling.