Supine or not supine? Our initial experience on oblique supine PCNL

Luca Timossi1, Gian Maria Badano1, Corrado Pezzica1, Tomaso Montanaro1, Emanuele Daglio1, Elvis Rikani1, Carlo Calcagno1, Carlo Introini1
  • 1 Ospedale Evangelico Internazionale (Genova)


To compare the efficacy and safety of percutaneous nephrolithotomy (PCNL) in the prone and modified supine positions.

Materials and Methods

The study cohort consisted of 50 patients, who underwent PCNL from January 2006 to December 2013. The first 30 cases undergo prone PCNL while the second 20 cases undergo oblique supine PCNL. Patients were included if they had kidney stones of at least diameter >2.0 cm and had not previously undergone nephrostomy; and if they did not have serious cardiovascular or cerebrovascular disease or a hemorrhagic tendency. All patients were definitively diagnosed
preoperatively by plain ultrasonography and Uro CT plain scan. PCNL procedure. The entire procedure was performed with the patients under general anesthesia. Patients randomized to the prone position group were placed in the lithotomic position,and retrograde ureteric catheterization was performed.All other procedures were completed in the prone position.In the oblique supine group 5 patient were subjected to ECIRS. All the kidney punctures were performed by ultrasound and fluoroscopic guidance for both the two groupes and the lower calyx was the most frequent site of target calyx puncture in both groups.In all the cases a 24ch nephrostomy catheter was inserted.


The mean operation time was not significantly different in the two groups with a mean time of 87 minutes for the prone position while the mean time was of 94 min for the patients who ungergo PCNL in oblique supine position. The stone free rate was of 83,3% in the group who undergo PCNL in the prone position. The rate of stone free was of 85% in the oblique supine group.No patient experienced major complications.There were no significant between group differences in use of analgesics, mean hospital stay, hospitalization expenses, medicine therapy, mean blood loss, and need for blood transfusion. The 5 patients who didn't result stone free after a prone PCNL were subjected 2 to ESWL treatment 2 to second look PCNL and 1 to a RIRS procedure. The 3 patients who didn't result stone free after oblique supine PCNL were subjected 2 to RIRS and 1 to ESWL.


PCNL is at this time the gold standard on the treatment of renal calculi greater than 2cm. Our initial experiences suggested that oblique-supine PCNL is a safe and effective choice that offers several advantages with excellent outcomes. PCNL with the patient in the supine position can provide uniform comfort for the anesthesiologist, patient, and surgical team.When the PCNL procedure is performed with the patient in the prone position, a ureteral catheter is commonly fixed in the lithotomy position before the patient is turned; however,PCNL in the supine position does not require turning. Furthermore, PCNL in the oblique supine position facilitates the completion of ureteroscopic processes at the same time with an encrease in stone free rate.


The prone position has been the traditional and most widely used position since PCNL emerged in the mid 1970s. Surgical advantages include straightforward renal puncture, spontaneous evacuation of stone fragments facilitated by horizontal sheath position and hand of surgeon is outside the field of radiation. Proposed technical advantages include uncomplicated patient positioning, less manipulation of patient under anesthesia and decreased operating room time.PCNL is a choice in the treatment of large kidney stones because of excellent outcomes and acceptably low morbidity.The prone approach provides a larger surface area for the choice of puncture site and a wider space for instrument manipulation. However, the prone position has several disadvantages:respiratory and cardiovascular risks; ventilatory difficulties, especially in obese patients and in elderly patients with compromised cardiopulmonary status; and the need for position changes during the procedure.Supine PCNL was first reported by Valdivia et al. in 1998 and is regarded as possessing several advantages. Anesthesiologists prefer the supine position because of better airway control during procedures and the less modification sin the blood pressure. Another advantage of the supine position is that there is no need for position changes to perform other endoscopic procedures such as cystoscopic or ureteroscopic operations. The supine position enables simultaneous retrograde ureteroscopic procedures during PCNL without any position change reducing the surgery time and improving the stone free rate.