Tokuda Hospital Sofia


Percutaneous nephrolithotomy - scientific study

PCNL – 60 consecutive patients - a study of the effectiveness and safety of the procedure in the beginning of a learning curve - abstract 

K. Davidoff MD, A. Popov MD, Department of Urology, Tokuda Hospital Sofia, Bulgaria


  1. Introduction

The first percutaneous nephrolithotomy series were described in the early 80s of the 20th century and since than the procedure have come a long way to become a worldwide recognized first line treatment for large renal calculi. A great deal of time and effort of now, generations of urologic surgeons have led to the development of large database of  knowledge on  the specifics, instrumentation, operative techniques, management of complications and safety procedures, thus shortening the learning curve and guarantying high level of patient safety and fast recovery rates.  The introduction of retrograde intra-renal surgery, the mini-perc and the tubeless ultra mini-perc have already challenged the supreme position of the classic PCNL, but are far away from replacing it in the everyday urologic surgery practice. Today standard rigid PCNL is still the method of choice in the treatment of large staghorn calculi and multiple nephrolithiasis. In this prospective single-center non-randomized study we present our initial experience with the PCNL procedure.

The purpose of this study is to demonstrate that standard rigid PCNL keeps it’s high level profile of safety and effectiveness in a beginning of a learning curve.

  1. Materials and methods.

We selected 60 consecutive patients who were proposed and consented to undergo mini-invasive operative procedure for kidney stone removal.

2.1  Inclusion criteria – age 18 to 80, men and women with at least one kidney stone with size bigger than 20 mm and no upper size limit.

2.2  Exclusion criteria – co-morbidity burden with APACHE II score bigger than 40, ASA index above III, any degree of cardio-vascular or pulmonary insufficiency based on underlying diseases, renal insufficiency with history of hemodialysis, age bellow 18 or above 90, solitary kidney, documented presence or suspicion of undergoing systemic uro-infection, renal abscess, pyonephrosis, co-existing ureterolithiasis, bilateral obstruction of the upper urinary tract, renal transplant, 

2.3  Evaluation parameters. We established two groups of  parameters – Effectivenes Evaluation Parameters and Safety Evaluation Parameters:

-          EEP - Stone Free Rates (SFR), Average Hospitalization Time (AHT), Mean Nephrostomy Drainage Time (MNDT).

-          SEP - Occurrence of Re-treatment (ORT), Complications Rate (CR),  and Procedure-Related Morbidity (PRM).

For the evaluation of the SFR, CR, PRM we set a follow up period of 90 days with follow up visits at 10th, 30th, 60th and 90th postoperative day. Final evaluation of the parameters is based on the data of the last follow up visit. For the pre-operative evaluation of the patient we used ultrasonography and KUB X-Ray for all patients. For the patients with radio-lucent stones we used non-enhanced CT of the abdomen and pelvis. For the postoperative evaluation we used sonography(30th, 60th and 90th postoperative day), KUB and control unenhanced CT at the 30th and 90th postoperative day.

2.4  Operative technique.

We used the standard rigid nephroscopy technique under fluoroscopy control. In the lithotomy position we inserted 6 Fr ureteral catheter which was than fixed to a 18 Fr Foley catheter, the patient was placed in prone position and the contrast-enhanced collecting system was punctured via fluoroscopy control. After obtaining access to the collecting system a guidewire was placed and a nephrostomy tract was created in a standard fashion using 28 or 30 Fr anplatz sheath at the end. We used rigid nephroscope with ultrasound probe for all procedures. At the end of the procedure we placed 24 Fr COOK nephro-ureterostomy set.

  1. Results.

60 consecutive patients were treated in the period between 01-JUL-2013 and 31-JAN-2014.

- Stone Free Rate – 50 patients were evaluated stone free at the 30th postoperative day, 53 at the 60th and 55 at the 90th postoperative day.

- Average Hospitalization Time was between 3 and 7 days with mean AHT of 5 days. All patients were dismissed after nephrostomy tube removal. The single criterion for tube removal was presence of clear color urine.

- Mean nephrostomy time was between 2 and 6 days with average MNT of 4 days.

- Procedure Related Morbidity was presented with one case of haemotorax wich was treated with open surgery and two cases of hydrotorax wich were treated conservatively with diuretic therapy. No cases of pneumothorax were observed. No reno-cutaneal fistulas were detected. We do not experienced major haemorhage accidents involving major renal artery branches injury, one patient underwent selective renal artery angiography for suspected lesion, the latter was not confirmed. No cases of renal parenchima ruptures were observed. We had no cases of intraabdominal entry related complications.

- Complications were registered in 10 cases  including steinstrasse of residual fragments(2),  hydronephrosis due to single or multiple obstructing ureter fragments(5), persistent nephrolithiasis of stone residuals(5). All steinstrasse and hydronephrosis cases were treated with secondary extraction of fragments via URS. All received double J stents. The cases of kidney residuals were managed with ESWL at the same hospitalization period, with n       o further treatment and were documented stone free at the 60th postoperative day control visit.

- Re-treatment was needed in 5 cases with total staghorn nephrolithiasis. All were managed stone free at retreatment.

  1. Discussion

The above results demonstrate sufficient  effectiveness  of the procedure even in the early stages of the learning curve. The overall low complications rate and the absence of  major complications described in the literature show that the current knowledge and protocols provide high level of safety in the beginning of the experience with the procedure. Mentioning the above it is clear that PCNL is always good alternative to the open surgery for kidney stone removal, even in the beginning, combining enough safety and effectiveness to meet high standards of patient care.

  1. 5.      Conclusions

The PCNL of kidney stones of any size is possible even in the early stages of the learning curve, without compromising the patient safety and treatment benefits. The procedure has very good safety and efficacy  profile in non-experienced hands when up-to-date protocols are followed. It is achievable to produce stone free rates comparable to the current standards, without experiencing major, long time complications. All of the observed complications in our series were manageable with miniinvasive and noninvasive approach.

  1. References:

1.Urinary Tract Stone Disease: P. Nagaraja Rao, Nagaraja P. Rao, John P. Kavanagh, Glenn M. Preminger  2010

2.EAU Guidelines on Urolithiasis 2011

3. A.Smith et al - Smith's Textbook of Endourology 3rd Ed - 2012

4. Advanced endourology – the complete clinical guide – Stephen Y. Nakada, MD; Margaret S. Pearle, MD, PhD - 2007

5. Manual of Endourology: R. Hohenfellner; J.-U. Stolzenburg - 2005.

6. Difficult Cases in Endourology: Ahmed Al-Kandari, ‎Michael Grasso, ‎Mahesh Desai - 2012

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