Comparative Analysis of A Novel Air-Bubble Guided Percutaneous Access Technique Against Traditional Fluoroscopic
Bruce M Gao1, Harel C Sims1, Ian Ong1
1Department of Urology, University of California, Irvine, Orange, California, USA.
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.
