1821 THE RELATIVE RENAL ANATOMY IN THE PRONE-FLEXED POSITION FOR PERCUTANEOUS NEPHROLITHOTOMY: A PROOF OF CONCEPT FOR OUR MODIFIED POSITION

Abstract

You have accessJournal of UrologyStone Disease: New Technology/SWL, Ureteroscopic or Percutaneous Stone Removal1 Apr 20111821 THE RELATIVE RENAL ANATOMY IN THE PRONE-FLEXED POSITION FOR PERCUTANEOUS NEPHROLITHOTOMY: A PROOF OF CONCEPT FOR OUR MODIFIED POSITION Joshua D. Wiesenthal, Edmund H. Ng, Michael Ordon, A. Andrew Ray, Daniela Ghiculete, Kenneth T. Pace, and R. John D'A Honey Joshua D. WiesenthalJoshua D. Wiesenthal Toronto, Canada More articles by this author , Edmund H. NgEdmund H. Ng Toronto, Canada More articles by this author , Michael OrdonMichael Ordon Toronto, Canada More articles by this author , A. Andrew RayA. Andrew Ray Toronto, Canada More articles by this author , Daniela GhiculeteDaniela Ghiculete Toronto, Canada More articles by this author , Kenneth T. PaceKenneth T. Pace Toronto, Canada More articles by this author , and R. John D'A HoneyR. John D'A Honey Toronto, Canada More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.1840AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Knowledge of relative renal anatomy is imperative when obtaining renal access during percutaneous nephrolithotomy (PCNL) while attempting to minimize morbidity and iatrogenic organ injury. The current study presents the anatomical basis for our position modification and demonstrates why the prone-flexed position facilitates percutaneous renal access and potentially minimizes its morbidity. METHODS Reconstructed abdominal-pelvic triphasic computed tomography was conducted on 16 patients in the prone and prone-flexed positions. The trajectory of nephrostomy access was virtually positioned at a 30 degree angle off the vertical axis lateral to the paraspinal muscles. RESULTS In the prone-flexed position, the left kidney was displaced lower than the right in 92.3% of cases, such that it would have lowered an upper pole puncture from above the 11th rib to one above the 12th rib in 5 of 11 patients (45.5%). When comparing the prone-flexed to the prone position, the mean skin-upper calyx distances were 8.4 mm and 13.4 mm shorter for the right and left kidneys, respectively (p<0.001). For lower pole punctures, the right and left kidneys were significantly lower (11.6 mm and 9.8 mm, respectively) in the prone-flexed as compared to prone position, p<0.001. The prone-flexed position moved the kidney further from the adjacent organs such that the planned trajectory was 13.6 degrees further away from the liver on the right side and 11.3 degrees further from the spleen on the left side (both p<0.001). In the prone-flexed position, the mean angle of trajectory of a rigid nephroscope from an upper pole puncture into the lower calyx was 101.3 degrees, whereas from a lower pole puncture into an upper pole calyx was more acute at 96.1 degrees (p<0.01). CONCLUSIONS In comparison to the standard prone position for PCNL, the prone-flexed modification shortens the skin-to-kidney distance, lowers the kidneys in relation to the ribs to minimize supracostal punctures, moves the liver and spleen away from potential upper pole punctures and flattens the natural lumbar lordosis to facilitate instrumentation from a lower pole puncture. Lastly, we demonstrate that there exists less infundibular torque during upper pole punctures when instrumenting lower pole calyces due to the more obtuse angle. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e730-e731 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Joshua D. Wiesenthal Toronto, Canada More articles by this author Edmund H. Ng Toronto, Canada More articles by this author Michael Ordon Toronto, Canada More articles by this author A. Andrew Ray Toronto, Canada More articles by this author Daniela Ghiculete Toronto, Canada More articles by this author Kenneth T. Pace Toronto, Canada More articles by this author R. John D'A Honey Toronto, Canada More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...