Figure 45.1
How ultrasound helps to easy identification of surrounding organs (lung, liver, spleen, intestine or liver) that are not visible in fluoroscopy. (a) Ultrasound image of a stone bearing kidney viewed from the 10th intercostals space; (1) surface 10th or 11th rib, (2) backshadow of ribs, (3) kidney parenchyma, (4) bright echo of stone backshadow. (b) During inspiration diffuse reflections caused by air in the lung obscures the view on the kidney, which moves caudally. (c, d) During deep inspiration the intercostals space is completely filled by the lung, indicating that this access should be avoided, as it will lead into the lung or thoracic cavity
The advantage of this combined visualization principle is to obtain real-time pseudo three-dimensional information during establishing the percutaneous access [1, 2]. Prior puncture of the kidney we routinely place an ureteral balloon catheter in the proximal ureter that allows retrograde filling and slight dilation of the renal collecting system with contrast dye and prevents loss of fragments into the ureter while later stone disintegration.
Ideal Access
The ideal approach to the kidney is achieved by a transpapillary puncture with direct access to the renal pelvis. The first step in preoperative planning of the procedure is to identify the ideal target calyx and to obtain a three-dimensional knowledge of the kidney and the stone. It is essential to understand the anatomical location of the kidney. It is located anterior to the psoas muscle, between 12th thoracic vertebral body and 2nd/3rd lumbal vertebral body. Both kidneys are located within the retroperitoneum at approximately 30° posterior to the frontal plane of the body. Access to the kidney is always established individually according to the particular anatomy. Frequently, the ribs or the iliac crest limit the space for access. In these cases, the area has to be shifted a few degrees (caudally or cranially 10–20°) (Fig. 45.2).
