Is routine micropuncture access necessary for percutaneous nephrostomy? A randomized trial

Objective: To compare the micropuncture technique and the conventional large-bore needle approach for renal access. Methods: From July 1999 to July 2000, patients referred to interventional radiology for emergent or elective percutaneous nephrostomy with normal coagulation profiles were considered for the study. Nephrostomy procedures were performed using a micropuncture system or large-bore needle for collecting system access; 24 nephrostomy procedures were randomized to each group using permuted blocks and opaque sealed envelopes. Gross hematuria, quantitative urine red blood cell counts, pain scores and procedural success were compared between the 2 groups. Results: There was a small difference in the incidence of gross hematuria between the large-bore needle and micropuncture groups (12 [50%] v. 8 [33%] patients), but this difference was not statistically significant. Quantitative urine red blood cell counts obtained immediately after and 24 hours after nephrostomy placement showed no significant differences. Significantly fewer needle passes were required for access in the large-bore needle group than the micropuncture group (1.7 v. 2.8, p = 0.01), and mean procedure duration was 7 minutes longer in the micropuncture group, although this difference was not significant. No differences in pain scores or procedure success were seen. Conclusion: Percutaneous nephrostomy performed with a micropuncture system in patients with normal coagulation profiles does not significantly decrease organ bleeding or pain. More needle passes and manipulations are required, which may increase procedure duration. The additional costs of routine micropuncture access for percutaneous nephrostomy are not supported by this study.