The Barts 'flank-free' modified supine position for percutaneous nephrolithotomy.

BACKGROUND The last decade has seen the emergence of a variety of supine positions for carrying out percutaneous nephrolithotomy (PCNL). These positions all differ with regard to ease of puncture under image guidance, operative field availability, ability to make and dilate multiple tracts and ease of combining retrograde intrarenal surgery (RIRS). As all of these positions have their limitations regarding the important parameters mentioned above, there is a need for a supine position which addresses some of the difficulties. METHODS We describe and illustrate our flank-free modified supine position, which we believe addresses a number of the issues. RESULTS Our position allows easy percutaneous access under fluoroscopy (torso only tilted to around 15°), space for placing (flank free of support) and dilating multiple tracts (kidney lies in a fairly neutral position and hence less mobile), a fairly horizontal tract allowing low intrarenal pressures and easy washout of fragments as well as allowing RIRS in a position of relative familiarity. The lesser torso rotation compared with the Valdivia, Galdakao modified and the Barts modified Valdivia positions also means it is more comfortable for patients. CONCLUSIONS Our results are encouraging and easily comparable with published series on prone position, Valdivia, complete supine and the Barts modified Valdivia positions. We would like to highlight the Barts 'flank-free' modified supine position as one of the standard positions for carrying out supine PCNL.