Lower calyx puncture site is approximately 1 cm lower and 1 cm inwards from the 12th rib tip
Under fluoroscopy guidance the puncture needle is placed on the skin along and in alignment with the target calyx axis. Immediately we set the first level of kidney access (coronal). Furthermore, aligning the access line with the infundibulum also allows the most efficient use of a rigid nephroscope and decreases the need for excessive torque on the rigid instruments, which may cause renal trauma and bleeding. The puncture line orientation towards the target calyx is easily performed simply by moving the fluoroscopy unit. The (continuous or in only two positions with increasing experience of the surgeon) change of the fluoroscopy unit position from the vertical to the lateral level gives in a two-dimensional image the correct position of the puncture needle towards the target calyx (Fig. 43.2).
Alignment of puncture needle with the long calyceal axis and its perpendicular projection
Tip : The ideal puncture plane is determined between the long calyceal axis and its perpendicular projection, while it is a direct, straight path to the renal pelvis as well the least traumatic.
With fluoroscopy unit placed vertical (sagittal plane or parallel to the puncture line) the movement of the needle is adapting our inward-outward direction, i.e. moving left–right. We define in this way the second level of puncture (transverse) (Fig. 43.3).
Fluoroscopy unit placed vertical. Needle movement is adapting our inward -outward direction, i.e. moving left–right
Needle axis and calyceal axis should carefully maintain a constant relationship. With fluoroscopy unit in a lateral position (30° towards the surgeon–side to the line of puncture) the movement of the needle fits in our cranial–caudal axis that moves up and down. We define in this way the third level of puncture (sagittal) (Fig. 43.4).