Comparative Analysis of A Novel Air-Bubble Guided Percutaneous Access Technique Against Traditional Fluoroscopic Techniques.

INTRODUCTION

Percutaneous nephrolithotomy (PCNL) requires precise renal access, a feat that is often challenging and time-consuming. In this light, we evaluated the bubble needle, a standard nephrostomy needle with an integrated two-dimensional bubble level designed to maintain anterior-posterior alignment after a single fluoroscopic image. We hypothesized that the bubble needle would streamline access while providing accuracy comparable to conventional fluoroscopic techniques and substantially reduced radiation exposure.

METHODS

Twenty-one participants (students = 9, residents = 5, attendings = 7) each performed, in random sequence, three punctures using traditional bull's-eye, rotated bull's-eye, and bubble needle techniques in a ballistic gel PCNL phantom with a radiopaque target at 10 cm depth. Outcomes were fluoroscopy dose milligray (mGy), fluoroscopy time (s), procedure time (s), and accuracy (mm). Data were analyzed with analysis of variance and mixed-effects models, adjusting for experience and trial number.

RESULTS

A total of 189 punctures were completed. Bubble needle achieved the lowest radiation dose and exposure time (0.23 ± 0.19 mGy; 6.90 ± 5.40 seconds), representing 74%/70% reductions vs traditional and 57%/54% vs rotated (p < 0.001). Mean procedure time (s) was significantly lower for bubble needle compared to the traditional technique (31.40 ± 13.71 s vs 40.46 ± 22.67 s; p = 0.008) and for rotated compared to traditional technique (25.22 ± 12.34 s vs 40.46 ± 22.67 s; p < 0.001). Mean accuracy (mm) was not significantly different among traditional, rotated, and bubble needle techniques (2.3 ± 3.4 mm vs 1.2 ± 2.7 mm vs 1.5 ± 1.5 mm; p = 0.077). Results were consistent across experience levels, with no significant learning effect across trials.

CONCLUSION

The bubble needle maintains accuracy comparable to conventional fluoroscopic techniques while decreasing procedure time and reducing radiation exposure by more than half.