Percutaneous nephrolithotomy (PCNL) is considered the treatment of choice for large urinary calculi and staghorn lithiasis. Several techniques have been described for the initial puncture and access. Herein we describe the technique used at our center for fluoroscopy-guided prone percutaneous puncture, which we call "needle kiss" technique.
We present a practical example of our technique step by step, in a case of posterior lower calyx puncture.
The procedure is performed with the patient under general anesthesia, and a 6Fr ureteral open-end catheter is advanced into the renal pelvis for contrast installation in the lithotomy position. Afterwards, the patient is placed in the prone position. Retrograde pyelogram through the catheter will show the upper urinary tract and calyceal anatomy.
Once we identify the target calyx for percutaneous access, a first needle (20G) is perpendicularly (90º) punctured through the skin, a correct puncture can be proven if urine comes out from the needle. This first puncture is crucial to determine the deepness of the calyx in relation with the skin. Next, with a larger 18G needle we realize the second puncture, this will be the access tract. Under fluoroscopy guidance, we advance the needle in the angulation and deepness needed to puncture through the calyceal-papilla-infundibulum axis. The main goal of our technique is to join both needle tips.

The inclination of the second needle (18G) puncture is guided by the deepness of the first needle (20G), a superficial puncture with the first needle will indicate a more superficial calyx and vice-versa.
We strictly recommend the use of radiation protective gloves, and minimizing the time of fluoroscopy exposure as much as possible.
After using this technique for prone percutaneous puncture at our center for several years, we can conclude it is safe, feasible, and provides quick percutaneous access without the use of ultrasound.