Position: Prone or Supine Is the Issue of Percutaneous Nephrolithotomy

Abstract

The prone position has been considered the only position for percutaneous access to the kidney for the past 25 years, whereas the supine Valdivia position has recently started to gain acceptance, although it was originally described in the late 1980s. Even more recently, the Galdakao-modified supine Valdivia position was described. However, there is no consensus on which is the best position for percutaneous nephrolithotomy, and the choice is currently based on the surgeon's preference. The prone, supine, and modified supine positions are described, pointing out the advantages, disadvantages, and results of each technique. A number of potential advantages have been described for the supine over the prone position: less cardiovascular change; no need for patient repositioning (with less associated risk of central and peripheral nervous system injury); less X-ray exposure to the surgeon; and less risk of colonic injury. The recently described Galdakao-modified supine Valdivia position allows for a simultaneous anterograde and retrograde approach to the renal cavities for the one-stage treatment of complex renal stones or concurrent renal and ureteral calculi. Moreover, the use of a flexible ureteroscope allows for Endovision puncture to achieve perfect access to the kidney. The prone position still represents the standard for percutaneous access to the kidney, and other positions should be compared with this position. However, the supine and the modified supine positions have potentially important advantages for both patients and surgeons that need to be investigated in a large randomised trial to define their superiority over the traditional prone position.