FIG. 3.

The transverse approach to renal access. (a) Anatomical landmarks are again presented for percutaneous nephrolithotomy in the prone position (P marks the paraspinous muscle, I the iliac crest, and R the 12th rib). (b) Image demonstrates how the ultrasound probe (yellow rectangular) is oriented along the transverse axis of the kidney for the transverse needle insertion technique. Two potential points of entry for the needle are marked by yellow dots. The location of the probe along the kidney axis and of the needle insertion relative to the probe head can change depending on the desired calix of entry and the patient's anatomy. (c) Schematic drawing of the coronal and axial views of the needle approach with the ultrasound probe positioned along the transverse axis of the kidney. A needle (represented by the black lines) can be inserted into a posterior calix of choice while ultrasound imaging shows the needle in cross section as a single echogenic point. (d) Intraoperative photographs demonstrate typical hand positions for the transverse needle insertion technique. The nondominant hand holds the ultrasound probe, while the dominant hand holds the needle. The needle can enter the patient's body from any distance to the head of the probe. In this picture, the needle is advanced from the back of the probe. (e) Intraoperative image of a transverse needle puncture where the needle is inserted from in front of the probe. The choice of insertion site depends on the desired angle of entry into the kidney calix of choice. (f) Ultrasonographic image of the kidney along its transverse axis demonstrates how the needle tip (white arrow) is imaged as it enters the renal calix. The probe is swept back and forth to keep the needle tip in view as it is inserted into the kidney.