Skip to main content
African Journal of Urology
African Journal of Urology Cover Image
Download PDF

Safety and efficacy of Chinese minimally invasive percutaneous nephrolithotomy in the management of renal stones ≤ 2 cm: a single-center experience

African Journal of Urology volume 25, Article number: 7 (2019) Cite this article

Abstract

Background

The goal for using smaller caliber instruments in PNL was to reduce the access-related complications and to decrease morbidity. The objective of this study was to evaluate the safety and efficacy of Chinese minimally invasive percutaneous nephrolithotomy (MIPNL) in the treatment of renal stones ≤ 20 mm.

Results

Sixty-seven patients completed the study protocol. The mean age was 41.10 ± 13.99 years (range 18–68 years). There were 43 (64%) male and 24 (36%) females. The mean stone size was ranged from 78.5 to 439.6 mm2 (mean ± SD 172.48 ± 69.54 mm2). The overall SFR was (82%). Twelve (18%) needed post-MIPNL auxiliary procedure, in the form of second MIPNL in 3 (4.5%) cases, SWL in 7 (10%), and RIRS in 2 (3%) cases. The intraoperative complication was present in four patients (5%) include bleeding necessitate blood transfusion in one patient (1.5%) and renal collecting system perforation 3 (4.5%). The postoperative complication was urine leakage 5 (7.5) and fever in 6 (9%) of patients.

Conclusion

Chinese MIPNL is safe and effective method for treatment of renal stone ≤ 20 mm size with satisfactory SFR and low complication rate when SWL failed or contraindicated. It is considered a feasible treatment alternative to standard PNL, in the absence of flexible URS or miniature nephroscope.

Background

Various treatment options are available for renal stones and several factors are weighted in determining the optimal treatment protocol. Although the nature of stone and patient’s medical condition appear to be the main factors, other factors as equipment availability, expertise, patients’ preference, procedure morbidity, and therapeutic outcome as well as factors related to economy must be considered as well [1, 2].

Standard percutaneous nephrolithotomy (PNL) is known to have higher clearance rates for stones 1–2 cm. Despite its high clearance rate, PNL is frequently considered a second-line therapy for several reasons, including procedure-related hemorrhages requiring a blood transfusion or intervention; also, in real-life practice, the usual 26/30 Fr tract size of PNL may be too large in the pediatric system and in some adult non-dilated systems. This has brought the need of using a smaller size tract [3, 4].

In 1990s, some Chinese urologists performed PNL through a small tract measuring 14–18 Fr by using an 8/9.8 Fr rigid ureteroscope and named it Chinese minimally invasive PNL (MIPNL) [5]. The goal for using smaller caliber instruments in PNL was to reduce the access-related complications and to decrease morbidity [6].

In the present study, we reported our experience with the safety and efficacy of Chinese MIPNL in treatment of renal stone ≤ 20 mm under some selective criteria “extracorporeal shockwave lithotripsy (SWL) failure or contraindication.”

Methods

This hospital-based, prospective, interventional study was carried out during the period from December 2015 to March 2018. All adult patients presented with renal stones less than 20 mm size, in whom SWL failed or contraindicated, were eligible for participation. The study protocol was approved by the research ethical committee of our institution, and all patients provided a written informed consent before inclusion. Patients with severe musculoskeletal abnormalities, active urinary tract infection, renal congenital anomalies, and coagulation disorders were excluded from the study.

Patients were evaluated by medical history taking, physical examination, laboratory investigation including urine analysis with urine culture, complete blood count, serum creatinine and coagulation profile, and renal ultrasonography. The diagnosis of renal stone was based on non-contrast computed tomography (NCCT) that was performed preoperatively in all cases.

Chinese MIPNL procedure

All procedures were performed under general anesthesia. With the patient in lithotomy position, a ureteric catheter was endoscopically inserted into the ipsilateral ureter for retrograde pyelography and visitation of pelvicalyceal system. With the patient in the prone position and under fluoroscopy guidance, the targeted calyx was punctured using 18-guage needle. Tract dilation was serially performed using Alken metal dilators from 8 Fr to 15 Fr, and a matched 16 Fr Amplatz sheath was placed. The stones were fragmented with holmium laser or pneumatic lithotripter through an 8/9.8 Fr rigid ureteroscope (Richard wolf, Karl Storz, Germany). The big fragments were removed with a stone forceps, while small fragments (< 3 mm) were removed by a combination of forceful retrograde saline flushing through the ureteric catheter and the effect of pulsatile irrigation through the sheath. Finally, a matched size nephrostomy tube (12 or 14 Fr) was inserted into the collecting system. If indicated, a double-J ureteral stent was inserted via the percutaneous tract under fluoroscopy with the assistance of guide wire.

Data collection and outcome measures

In all cases, serum creatinine, complete blood count, and abdominal pelvic ultrasonography were performed at the second postoperative day, and NCCT was performed at the postoperative week 2. The primary outcome measure was the stone-free status as detected by NCCT. Patient with no stone or residual fragment(s) < 4 mm was considered stone free. The secondary outcome measures were the operative time, fluoroscopy time, intra- and postoperative complication, and need for auxiliary procedure.

Data analysis

Statistical package for social sciences (SPSS) ver. 21 (IBM cooperation New York, NY, USA) software was used for statistical analysis. The categorical data were presented in the form of number (percentage) and numerical data in the form of median or mean ± standard deviation (SD) and range. Sample size calculation was performed.

Results

Sixty-seven patients completed the study protocol; there were 43 (64%) males and 24 (36%) females, ranged in age from 18 to 68 years (mean 41.10 ± 13.99 years). The stone size ranged from 10 to 20 mm (mean 14.17 mm). The demographics data and clinical characteristics of studied patients as well as the preoperative radiologic findings are summarized in Table 1.

Table 1 The demographics data, clinical characteristics, and preoperative radiologic findings
Full size table

After initial MIPNL, 55 (82.0%) patients were rendered stone free. From them, 50 (74.6%) had no stone and 5 (7.5%) had clinically insignificant residual fragment(s). The operative time ranged from 40 to 190 min (mean 74.58 ± 30.34 min). The hospital stays ranged from 2 to 7 days (mean 3.34 ± 1.62 days).

Double-J ureteral stent was inserted in four (6%) patients. It was due to pelvic perforation in three (4.5%) patients, and single functioning kidney in one.

In the 12 (18%) patients with failed MIPNL, second MIPNL was performed in 3 (4.5%), SWL in 7 (10%), and retrograde intrarenal surgery (RIRS) in 2 (3%) cases.

As shown in Table 2, the intraoperative complication was reported in 4 (5.0%) patients. It was in the form of bleeding requiring blood transfusion in one (1.5%) and perforation of renal collecting system in 3 (4.5%). The reported postoperative complication was urine leakage in 5 (7.5%) patients and postoperative fever 6 (9.0%).

Table 2 Intra- and postoperative complications
Full size table

Discussion

SWL generally is considered to be the first-line therapeutic option for most renal stones < 2 cm [7, 8]. SWL outcome are influenced by stone composition, the lower calyceal angle that permits the clearance of the resultant residuals, and the patient’s body habits, which may decrease the efficacy of SWL and increase the re-treatment rate [9].

In the present study, Chinese minimally invasive (MIPNL) is defined as a PNL technique with small working sheath, which is performed using an 8–9.8 Fr URS through a 16 Fr percutaneous renal access tract, this is technique was used also by other [10, 11].

In our study, the overall stone-free rate (SFR) after MIPNL was (82%). This result are comparable to results published by Li et al. [12] Huang et al. [10], and Giusti et al. [13] who reported the SFR of 83.9%, 85.4%, and 77.5%, respectively.

The only reported major intraoperative complication is the bleeding in one patient 1.5%, that needed blood transfusion; these results are less than to those reported by Huang et al. [10], who reported bleeding in four patients (9.8%) with only one patient (2.4%) requiring blood transfusion.

Pelvicalyceal perforation was reported in three patients (4.5%). Zhong et al. [10] reported pelvic perforation in two patients (6.9%), and on the other hand, Hung et al. [14] and Knoll et al. [15] reported no pelvic perforation in any of patients during MIPNL procedure.

Leakage and fever were the most common postoperative complications in five patients (7.5%) and six patients (20%), respectively. Hung et al. [10] reported leakage in two patients (4.9%) and fever in five patients (12.1%), and Lu et al. [11] reported leakage in 3.1% and fever in 15.6% post-MIPNL.

The use of auxiliary procedures such as SWL, RIRS, and second PNL may be necessary to achieve high SFR. The possibility of needing such auxiliary procedure to achieve a satisfactory outcome should be explained to the patients.

In our study, because of 12 (18%) patients with failed MIPNL, second MIPNL was performed in 3 (4.5%) cases, SWL in 7 (10%), and RIRS in 2 (3%) cases. De Le et al. [16], Hung et al. [10], and Monga et al. [17] reported auxiliary procedure post-MIPNL in 21.4%, 14.6%, and 9.5%, respectively.

The body mass index of our patients did not make a significant difference nor need special modifications in our tools in order to complete our procedure. Sometimes only, it consumes more time in positioning and more effort for successful puncture in such patients with high BMI.

The learning curve of a single surgeon suggests that competence at performing classic PNL is an important step to make learning curve of this technique better and faster. However, it needs some more time than classic PNL due to difficulties related to vision, diminished irrigation, and limited field.

We named some limitations in our study. Firstly, this was a study about a small group of patients. Secondly, it was the early experience of our center in practicing this technique. Thirdly, there is need for comparison with other procedures like RIRS.

There were some difficulties that faced us and caused decreased SFR, the diminished intraoperative field visibility (especially when patient had bleeding), the need for fragmentation into very small stones suitable for ureteroscopic graspers and/or baskets, and the small sheath.

Conclusion

Chinese MIPNL is safe and effective method for treatment of renal stone ≤ 20 mm size with satisfactory SFR and low complication rate when SWL failed or contraindicated. It is considered a feasible treatment alternative to standard PNL, in the absence of flexible URS or miniature nephroscope.

Availability of data and materials

The datasets generated and analyzed during the current study are not publicly available because that is the policy of our university but are available from the corresponding author on reasonable request.

Abbreviations

PNL:

percutaneous nephrolithotomy

MIPNL:

minimally invasive percutaneous nephrolithotomy

NCCT:

non-contrast computed tomography

BMI:

body mass index

SFR:

stone-free rate

SWL:

shock wave lithotripsy

URS:

ureteroscopy

RIRS:

retrograde intrarenal surgery

References

  1. 1.

    Ramello A, Vitale C, Marangella M (2000) Epidemiology of nephrolithiasis. J Nephrol 13(Suppl 3):S45–S50

    PubMed  Google Scholar 

  2. 2.

    Aydemir H, Budak S, Kumsar Ş et al (2014) Efficacy of surgical techniques and factors affecting residual stone rate in the treatment of kidney stones. Turk J Urol 40:144–149

    Article  Google Scholar 

  3. 3.

    Chan DY, Jarrett TW (2000) Mini-percutaneous nephrolithotomy. J Endourol 14:269–273

    CAS  Article  Google Scholar 

  4. 4.

    Mishra S, Sharma R, Garg C, Kurien A et al (2011) Prospective comparative study of Miniperc and standard PNL for treatment of 1 to 2 cm size renal stone. BJU Int 108:896–899

    PubMed  Google Scholar 

  5. 5.

    Li X, Zeng GH, Yuan J, Wu KJ, Shan CC et al (2004) Treatment of upper urinary calculi with the PCNL technique (Experience of 20 years). Beijing Da Xue Xue Bao 36:124–126

    PubMed  Google Scholar 

  6. 6.

    Kamal W, Kallidonis P, Kyriazis I, Liatsikos E (2016) Minituriazed percutaneous nephrolithotomy: What does it mean? Urolithiasis 44(3):195–201

    CAS  Article  Google Scholar 

  7. 7.

    Chaussy C, Fuchs G (1986) Extracorporeal lithotripsy in the treatment of renal lithiasis 5 years’ experience. J Urol (Paris) 92(6):339–343

    CAS  Google Scholar 

  8. 8.

    Wu H, Wang J, Lu J, Wang Y, Niu Z (2016) Treatment of renal stones ≥ 20 mm with extracorporeal shock wave lithotripsy. Urol Int 96(1):99–105

    CAS  Article  Google Scholar 

  9. 9.

    Fayad AS, Elsheikh MG, Ghoneima W (2016) Tubeless mini-percutaneous nephrolithotomy versus retrograde intrarenal surgery for lower calyceal stones of ⩽2 cm: a prospective randomised controlled study. Arab J Urol 15(1):36–41

    Article  Google Scholar 

  10. 10.

    Huang Z, Fu F, Zhong Z, Zhang L, Xu R, Zhao X (2012) Chinese minimally invasive percutaneous nephrolithotomy for intrarenal stones in patients with solitary kidney: a single-center experience. PLoS ONE 7(7):e40577

    CAS  Article  Google Scholar 

  11. 11.

    Lu Y, Ping JG, Zhao XJ, Hu LK, Pu JX (2013) Randomized prospective trial of tubeless versus conventional minimally invasive percutaneous nephrolithotomy. World J Urol 31(5):1303–1307

    Article  Google Scholar 

  12. 12.

    Li LY, Gao X, Yang M, Li JF, Zhang HB et al (2010) Does a smaller tract in percutaneous nephrolithotomy contribute to less invasiveness? A prospective comparative study. Urology 75(1):56–61

    Article  Google Scholar 

  13. 13.

    Giusti G, Piccinelli A, Taverna G, Benetti A, Pasini L et al (2007) Miniperc? No, thank you! Eur Urol 51(3):810–814

    Article  Google Scholar 

  14. 14.

    Zhong W, Zhao Z, Wang L, Swami S, Zeng G (2015) Percutaneous-based management of Staghorn calculi in solitary kidney: combined mini percutaneous nephrolithotomy versus retrograde intrarenal surgery. Urol Int 94(1):70–73

    Article  Google Scholar 

  15. 15.

    Knoll T, Wezel F, Michel MS, Honeck P, Wendt-Nordahl G (2010) Do patients benefit from miniaturized tubeless percutaneous nephrolithotomy? A comparative prospective study. J Endourol 24(7):1075–1079

    Article  Google Scholar 

  16. 16.

    de la Torre G, De Bonis W, Rey H, Fredotovich N (2005) Percutaneous renal surgery with minimal access: miniperc. Arch Esp Urol 58(2):145–150

    Article  Google Scholar 

  17. 17.

    Monga M, Oglevie S (2000) Minipercutaneous nephrolithotomy. J Endourol 14:419–421

    CAS  Article  Google Scholar 

Download references

Acknowledgements

Not applicable.

Funding

None.

Author information

Affiliations

  1. Urology Department, Faculty of Medicine, AL-Azhar University, Cairo, Egypt

    Elsayed M. Salih, Ibrahim Elsotohi, Mohamed Elsalhy & Mourad M. Mourad

  2. Urology Department, Fayoum University, Fayoum, Egypt

    Hisham Elhelaly

Authors
  1. Elsayed M. Salih
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Ibrahim Elsotohi
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Hisham Elhelaly
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Mohamed Elsalhy
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Mourad M. Mourad
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

ES contributed to protocol development, data collection, and manuscript writing. IE contributed to data collection and manuscript editing. HE collected and analyzed data. ME contributed to data analysis and manuscript writing. MM contributed to data analysis and manuscript revision. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Elsayed M. Salih.

Ethics declarations

Ethics approval and consent to participate

In this study, all procedures performed involving human participants were in accordance with the ethical standards of our institution; faculty of medicine, Al-Azhar university and approved by tow ethical committee the first one in the ethical committee of urology department and the other in the ethical committee of faculty of medicine. At that time, there was no number to be given to the study but after that the numbering system became routine. The informed consent obtained from study participants was written.

Consent for publication

Not Applicable.

Competing interests

The authors declare that they have no competing interests.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Salih, E.M., Elsotohi, I., Elhelaly, H. et al. Safety and efficacy of Chinese minimally invasive percutaneous nephrolithotomy in the management of renal stones ≤ 2 cm: a single-center experience. Afr J Urol 25, 7 (2019). https://doi.org/10.1186/s12301-019-0002-5

Download citation

Keywords

  • Renal stone
  • Minimally invasive percutaneous nephrolithotomy
  • Extracorporeal shockwave lithotripsy
  • Ureteroscope
  • Stone-free rate