Retrograde instrumentation of the upper urinary tract, such as ureterorenoscopy, uses under endoscopic guidance the anatomically predestined access via the urethra and ureter, while techniques of antegrade instrumentation require a percutaneous puncture. This approach must respect the intrarenal anatomy just as in open surgical nephrotomy, and imaging techniques are required to guide the procedure.
First, and most important, a puncture direction must be determined that will provide straight access to the target and safe, bloodless instrumentation. Visualization of both the puncture needle and the target and precise guidance of the needle tip to the target require imaging techniques such as ultrasound, fluoroscopy, and, in selected cases, computed tomography (CT).
Contraindications to percutaneous kidney puncture are blood-clotting anomalies due to coagulopathies or pharmacologic anticoagulation. Preparation and draping of the surgical field are required as for open surgery, and the same standards of asepsis must be followed. Local anesthesia only is sufficient for puncture of the kidney and small-bore tract dilation (6–12F), for antegrade insertion of a ureteral stent or nephrostomy catheter. Lidocaine hydrochloride 2% USP, 10 mL, can be given for infiltration of the skin and tissues along the intended tract of puncture down to the renal capsule. During dilation of the tract, administration of a local anesthetic in lubricant (eg, lidocaine hydrochloride jelly 2%) serves the dual purpose of anesthetization and lubrication. Dilation of nephrostomy tracts up to 30F and extraction of small renal stones can be done under local anesthesia.
Percutaneous nephrolithotomy (PNL) remains indicated for treatment of large stones, staghorn calculi, and stones in caliceal diverticula. The extent of intrarenal instrumentation for stone disintegration and extraction usually requires epidural or general anesthesia. Because puncture, tract dilation, and stone disintegration and removal are preferably performed as a one-stage procedure, the use of local anesthesia in PNL is limited.
Percutaneous puncture of the renal collecting system may be performed for diagnostic procedures (eg, antegrade pyelography, pressure/perfusion studies) or to establish access for therapeutic interventions (Table 8–1).
Table 8–1. Indications for Percutaneous Puncture of the Renal Collecting System. ||Download (.pdf)
Table 8–1. Indications for Percutaneous Puncture of the Renal Collecting System.
Pressure/perfusion study (Whitaker test)
Nephrostomy catheter drainage
Antegrade ureteral stenting
Dilation of ureteral strictures
Percutaneous resection and coagulation of urothelial tumors
Both ultrasonic scanning and fluoroscopy provide visualization and guidance for a safe, accurate percutaneous puncture, but ultrasound has the following definite advantages:
No intravenous or retrograde administration of contrast dye
No radiation exposure
Continuous real-time control of puncture
Imaging of radiolucent, non–contrast-enhancing renal and extrarenal structures (eg, renal cyst, retroperitoneal tumor) for puncture
Imaging of all tissues along an intended nephrostomy tract (eg, bowel, lung)
Imaging in numerous planes simply by shifting, tilting, and rotating the scanning head
Three-dimensional information during puncture