Category: New Technology: Stones

MP31-7 - Electromagnetic Guided Percutaneous Renal Access Outcomes Among Surgeons of Different Experience Levels: A Pilot Study

Sun, Sep 23
2:00 PM - 4:00 PM

Introduction & Objective : Gaining percutaneous renal access has a steep learning curve with traditional techniques.  Electromagnetic (EM) guidance is an appealing technology for access as it allows real time, three-dimensional targeting without any radiation.  To date, few studies have explored EM guidance as it relates to percutaneous nephrolithotomy (PCNL) and no prior work has evaluated whether such technology can potentially decrease the learning curve in gaining access.  We sought to determine the feasibility of a new EM guidance system (Auris Health, Redwood City, CA) in obtaining percutaneous access, as compared to fluoroscopic guided access, in a porcine model among urologists of different experience levels.


Methods : Voluntary participants included urology sub-interns, residents, fellows and faculty. They were categorized into three cohorts: Beginner (n=6; 0-10 prior PCNL cases), Intermediate (n=4; 10-100 cases) and Advanced (n=4; >100 cases).  Beginners were provided verbal guidance during punctures from mentors with no hands on help.  Each participant performed an EM and fluoroscopic guided puncture, the order of which was switched with each subsequent participant.  Primary outcome was successful puncture, determined by endoscopic visualization of the needle entering the desired calyx.  Secondary outcomes included access time, fluoroscopy time, and number of attempts.  Participants were limited to 3 attempts and 10 minutes total to obtain access using each technique.The study was approved by local institutional review board and institutional animal care and use committee.


Results : 14 participants attempted 28 punctures.  Overall success using EM guidance was 93% compared to 71% using fluoroscopy (p=0.33). Median fluoroscopy time was 1.6 min in the fluoroscopy cohort compared to 0 in the EM cohort, excluding the initial retrograde pyelogram. EM guided punctures had shorter overall times (1.4 vs. 4.2 min, p <0.01) with fewer number of attempts (1 vs. 2, p <0.01).  Beginners showed comparable success rates and outcomes relative to the advanced group despite higher access times (Figure 1).


Conclusions : EM guidance is a promising new technique to decrease the learning curve of percutaneous renal access with high success rates and minimal radiation exposure, even among beginners.

Michael S. Borofsky

Assistant Professor
University of Minnesota
Minneapolis, Minnesota

Marcelino E. Rivera

Assistant Professor
Mayo Clinic (Rochester)
Rochester, Minnesota

Casey A. Dauw

Assistant Professor
University of Michigan
Ann Arbor, Michigan

Amy E. Krambeck

Professor
Indiana University School of Medicine
Indianapolis, Indiana

James E. Lingeman

Professor
Indiana University School of Medicine
Indianapolis, Indiana