The relationship between vascular distribution and puncture route during PCNL. The diagram in the left is a cross-section of the kidney to illustrate the puncture through the axis of calyx can avoid renal vascular damage. The diagram in the right is a local enlargement of the renal pyramid and its peripheral vascular distribution, which shows the corresponding relationship between the renal pyramid and the calyx, and the puncture path through the axis of the calyx will minimize the damage to the vessels around the renal pyramid.