AUA 2017: Comparison of Ultrasound-Guided, Conventional Fluoroscopic, and a Novel Laser Direct Alignment Radiation Reduction Technique for Percutaneous Nephrolithotomy

Boston, MA ( Percutaneous nephrolithotomy (PCNL) is the routine standard treatment for patients with moderate to complex renal calculi. Routinely to gain access to the kidney, through the abdominal wall, urologists use either ultrasound or conventional fluoroscopic guidance. With the goal of reducing radiation exposure to patients during surgery, novel laser Direct Alignment Radiation Technique was developed (DARRT). This technique utilizes a laser sight attached to the C-arm and follows similar methodology as the standard bulls-eye technique. After initial C-arm triangulation, the laser is used as a line of sight. Endoscopic assistance is required to visualize the needle from within the kidney, this allows for the surgeon to determine whether the needle is within the laser tract.

The current study by Dr. Abourbih and colleagues was a retrospective chart review in which 25 consecutive cases in which DARRT was used, was compared to 25 US-guided and conventional CT guided cases. All 3 groups were matched in respect to preop characteristics (i.e. age, stone burden, location etc.). The primary endpoints were total radiation time and access radiation time. The study team also assessed operative time, EBL, SFS, and major complications (≥Clavien III). Patients were defined as stone free if residual fragments were ≤4 mm.

When analyzing operative time and major complications, all three modalities had similar results. In regards to stone-free rates, there was no statistically significant difference; however, Dr. Abourbih notes that there is trend towards an increased stone free rate in those who underwent PCNL with DARRT. Both access and total fluoroscopic time decreased significantly in the ultrasound and DARRT groups when compared to conventional CT. Access time dropped from 844s in the conventional group to only 3.1s and 8.9s in the US and DARRT groups, respectively. Unfortunately, the study team did not analyze whether there was a difference between US and DARRT cohorts; however, Dr. Abourbih acknowledged that this analysis was in the plans for further investigation. Overall, the study team concludes that US and DARRT methods are viable and effective methods for access during PCNL with comparable stone-free rates.

Presented By: Samuel Abourbih of Loma Linda University, Loma Linda, California, USA

Authors: Samuel Abourbih, Mohamed Keheila, Patrick Yang, Muhannad Alsyouf, Jason Smith, Braden Mattison, Nazih Khater, Jim Shen, Salim Cheriyan, D. Duane Baldwin, Loma Linda, CA

Written By: Anthony Warner, a research intern from the University of California, Irvine, on behalf of

at the 2017 AUA Annual Meeting - May 12 - 16, 2017 – Boston, Massachusetts, USA