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Table of Contents
Year : 2019  |  Volume : 30  |  Issue : 1  |  Page : 36-39

Our experience with Miniperc XS in the management of renal stones

Department of Urology, Dr. D. Y. Patil Medical College and Hospital, Pune, Maharashtra, India

Date of Web Publication2-Jan-2019

Correspondence Address:
Deepakkumar Mane
Department of Urology, Dr. D. Y. Patil Medical College and Hospital, Pimpri, Pune - 411 018, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/UROS.UROS_107_18

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Objective: This study was conducted to evaluate the efficacy and safety of Miniperc (MIP) XS (7.5 Fr) nephroscope in the treatment of renal stones up to 20 mm. Methods: This was a prospective study that enrolled 65 patients with limited stone burden in calyx or pelvis, which were treated with MIP XS. Primary outcomes included stone-free rates (SFRs), operative time, length of postoperative hospital stay, requirement of analgesic postsurgery, decline in hematocrit, stent requirement, and complications and requirement of ancillary procedure. Results: The mean stone size was 17.46 ± 2.9 mm. The patients were treated with MIP XS and had a mean operative time of 38.63 ± 8.4 min, 1.74% drop in hematocrit levels postsurgery and 96.9% SFRs. The length of hospital stay was 55.48 ± 4.6 h. Postoperative fever and nephrostomy leakage occurred in 9 and 1 patients, respectively. Six cases required some drainage procedure (double-J stent/nephrostomy). No patient required blood transfusion. Conclusion: This study showed that MIP XS could be considered as an effective treatment option in the treatment of renal stones up to 20 mm as it scores in all the standard parameters used to measure percutaneous nephrolithotripsy outcomes.

Keywords: Miniperc, Miniperc XS, percutaneous nephrolithotripsy, renal calculi

How to cite this article:
Sabale V, Pramanik P, Mane D, Satav V, Shah AS, Chaudari N, Kandari A. Our experience with Miniperc XS in the management of renal stones. Urol Sci 2019;30:36-9

How to cite this URL:
Sabale V, Pramanik P, Mane D, Satav V, Shah AS, Chaudari N, Kandari A. Our experience with Miniperc XS in the management of renal stones. Urol Sci [serial online] 2019 [cited 2022 Dec 4];30:36-9. Available from: https://www.e-urol-sci.com/text.asp?2019/30/1/36/249261

  Introduction Top

Urolithiasis is a serious health condition that has caused a significant burden worldwide.[1] The urinary tract stone disease is known to be affecting 10.6% of men and 7.1% of women in 2012 in the United States, and the prevalence continues to increase across the globe and is influenced by diet, lifestyle, and comorbidities.[2],[3] The increasing incidence of renal stones of all sizes creates the need of a safe and efficacious treatment option.

Percutaneous nephrolithotomy (PCNL) is a widely established treatment technique for renal stone but with the risk of morbidities and several complications such as bleeding, calyceal and infundibular tear, persistent leakage of urine, and nephron loss. This could have been due to several factors that include pelvicalyceal anatomy, stone size, tract size, number of access sites, operative time, or comorbidities.[4],[5],[6] The existing literature suggests that decrease in tract size has less morbidities and complications and this led to the advent of Miniperc (MIP).[7],[8],[9],[10],[11] The MIP has shown to achieve higher stone-free rates (SFRs) while minimizing complications and morbidities compared with other procedures.[12],[13] The invention of mini PCNL has made the paradigm shift for the management of renal stones and moving away from conventional techniques such as extracorporeal shock wave lithotripsy (ESWL). Therefore, PCNL could be considered as a treatment option for stones up to 10–20 mm as suggested by the European Association of Urology guidelines.[14]

MIP XS (MIP XS-Karl Storz®) is a unique integrated system. This study was done using MIP XS system (7.5 Fr) with a 9.5-Fr fixed sheath and this is the first study done with this system.

  Methods Top

Study design and patients

This study was conducted between October 2015 and January 2017 at the Department of Urology at D. Y. Patil Medical College and Hospital, Pimpri, Pune (Clinical trial number: DPU/R&R(M-SS)979(3)/2016).

A total of 65 patients with single renal stone (up to 20 mm size) in the calyx/pelvis were enrolled in the study and treated with MIP XS nephroscope (7.5 Fr) [Figure 1] with a 9.5-Fr fixed sheath [Figure 2]. Patients with deranged coagulation profile, pregnancy, and active urinary tract infection were excluded from the study. Stone burden was measured as the largest linear dimension on kidney-ureter-bladder (KUB) films. Intravenous urography was done to plan the surgery and to assess the pelvicalyceal system anatomy.
Figure 1: Miniperc XS 7.5 Fr

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Figure 2: Sheath of 9.5 Fr used for Miniperc XS

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The study was conducted in accordance with the International Conference on Harmonisation guidelines and approval from the Institutional Ethical Committee.

Study outcomes and procedures

The primary assessments were done in the following parameters:

  1. Operative time – Time taken from puncture to removal of access sheath
  2. Loss of blood – Measured by evaluating difference in preoperative (24 h before surgery) hematocrit and postoperative hematocrit measured 24 h after surgery
  3. Rate of stone clearance – Postoperative X-ray after 48 h followed by ultrasonography (USG) and X-ray KUB at 4 weeks
  4. Duration of postoperative stay – Measured from the time of surgery to the time of discharge
  5. Any ancillary procedure requirement
  6. Any postoperative complications.

Complete clearance was defined as no residual calculus or insignificant residual stone material (<4 mm) as seen after 4 weeks on X-ray KUB/USG. All patients were treated on a standard protocol of 1 shot antibiotic (ceftriaxone) preoperatively followed by 2 shots in 48 h. PCNL was done by using a standard procedure followed in our department. Initially, ureteric catheter was put in lithotomy position in all patients followed by fluoroscopic-guided puncture in suitable calyx in prone position. Guidewire was passed through the puncture needle followed by single-step dilation of 9.5 Fr and insertion on MIP XS to visualize the stones. Patients who presented with symptoms of fever or urosepsis postsurgery were administered appropriate antibiotics until the resolution of symptoms. The surgery was considered success when patients achieved complete clearance postsurgery and did not require any further intervention.

  Results Top

Sixty-five patients treated with MIP XS nephroscope were part of the study. The demographic characteristics of patients are presented in [Table 1]. The mean age of patients was 36.5 ± 14.2 years and body mass index was 21.8 kg/m2. The mean tract size was 9.5 Fr for MIP XS nephroscope. The source of energy used in all patients was holmium laser for stone fragmentation [Figure 3].
Table 1: Demographic characteristics of patients

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Figure 3: Holmium laser stone fragmentation

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The operative time for the patients was 38.6 ± 8.4 min, with a stone clearance rate of 96.9% at 48 h and 100% at 1-month follow-up. The duration of hospital stay was 55.48 ± 4.6 h. The requirement of analgesic was 60.0 mg of tramadol postsurgery [Table 2]. The number of puncture sites was 59 in lower calyceal, 4 in middle calyceal, and 2 in upper calyceal regions.
Table 2: Outcomes after the procedure

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Fifty-nine of 65 patients had tubeless PCNL procedures. Intraoperatively, no patients suffered from pelvic perforation. One patient each had bleeding (which obscured vision and hence the procedure had to be abandoned) and calyceal tear (which did not affect the procedure).

Double-J (DJ) stenting was performed in four patients and 7-Fr feeding tube nephrostomy had to be kept in two patients. The symptoms of fever were reported in nine patients postoperatively within 48 h (Grade 1 of Clavien–Dindo classification). Antipyretics were administered to these patients to reduce the symptoms. One patient experienced nephrostomy leakage [Table 2].

  Discussion Top

A detailed comparison study using MIP XS with other modalities using smaller or larger sheaths is still not available and, in fact, individual studies on 7.5-Fr MIP XS are also not available.

This study demonstrated that MIP XS nephroscope was associated with shorter hospital stay, insignificant hematocrit drops, reduced analgesia requirement, a smaller number of intraoperative complications, and a greater number of tubeless procedures.

The mean stone size in the present study was 17.46 mm in MIP XS patients. This was in accordance with a similar study done by Mishra et al., in which the mean stone size was 14.7 mm and MIP was used as a treatment option.[15]

In the present study, surgery performed with MIP XS had a mean operative time of 38.63 min. In a recently published review by Ruhayel et al., the operative times are longer even with mini PCNL procedure that ranged from 36 to 89 min.[16]

In this study, intraoperative complications, including bleeding and calyceal tear, each occurred in one patient with MIP XS. Bleeding is a complication that can occur during PCNL and can be managed conservatively. In our case, bleeding led to the loss of vision because of which the procedure had to be abandoned, but the postoperative hematocrit drop was insignificant for this patient also. In another study, bleeding was significantly less in MIP group compared with standard PCNL (0% vs. 4%).[15]

The mean drop in hematocrit in this study was 1.74%. No patient required blood transfusion in this study. This suggests that the use of a smaller bore tract to perform PCNL results in reduced loss in hemoglobin. It has been shown that the blood transfusion rates were lower for MIP compared with standard PCNL (4.49% and 6.31%, respectively).[17] This is also in concordance with a recently published systematic review in which patients had significantly lesser blood loss (1.8% in randomized controlled trials and 0.8%–4.4% in comparative studies) when surgery was performed using mini PCNL as compared to standard PCNL.[16]

In the present study, high SFRs were observed (in 96.9% of patients) in 48 h and 100% at 1-month follow-up. This is in line with several studies published previously that showed SFRs in the range of 93%–100% in MIP procedures, after 1-month postsurgery.[15]

The mean hospital stay was 55.48 h for these patients. These results were comparable with that of the previous studies which had hospital stays of 1.1–4.7 days in randomized studies and 3.2 days in nonrandomized comparative studies performed with MIP.[16],[18],[19],[20] Resolution of hematuria, postoperative pain, and complete recovery from postoperative stress were the main factors contributing to longer hospital stay.

There was no requirement of any ancillary procedure to any patient in our study. In the current study, 59 procedures were completely tubeless without DJ stent and nephrostomy tube. The tubeless mini PCNL has shown to have shorter operative time, shorter hospital stays, less postoperative pain, and shorter time to return to normal activities in previous studies that might result in lower morbidity in mini PCNL.[20],[21],[22],[23]

The analgesic requirement in the current study was quite low in patients who underwent tubeless procedures. This could have been observed due to smaller tract size and no nephrostomy tube/DJ stent. The recently published meta-analysis had also shown reduced requirement of analgesics in the tubeless PCNL group as compared to those with DJ stent or nephrostomy in situ.[22]

  Conclusions Top

This unique study demonstrated that surgery performed using MIP XS is safe as MIP XS scores in all parameters used to measure the success of standard PCNL result such as reduction in blood loss, shorter hospital stays, and high stone clearance rates with minimal complications. This suggests that MIP XS can be considered as an effective alternative treatment option in patients having calyceal stone up to 20 mm and is a viable one-time single-sitting alternative to ESWL.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Raheem OA, Khandwala YS, Sur RL, Ghani KR, Denstedt JD. Burden of urolithiasis: Trends in prevalence, treatments, and costs. Eur Urol Focus 2017;3:18-26.  Back to cited text no. 1
Scales CD Jr., Smith AC, Hanley JM, Saigal CS, Urologic Diseases in America Project. Prevalence of kidney stones in the United States. Eur Urol 2012;62:160-5.  Back to cited text no. 2
Antonelli JA, Maalouf NM, Pearle MS, Lotan Y. Use of the national health and nutrition examination survey to calculate the impact of obesity and diabetes on cost and prevalence of urolithiasis in 2030. Eur Urol 2014;66:724-9.  Back to cited text no. 3
Skolarikos A, de la Rosette J. Prevention and treatment of complications following percutaneous nephrolithotomy. Curr Opin Urol 2008;18:229-34.  Back to cited text no. 4
Kukreja R, Desai M, Patel S, Bapat S, Desai M. Factors affecting blood loss during percutaneous nephrolithotomy: Prospective study. J Endourol 2004;18:715-22.  Back to cited text no. 5
de la Rosette JJ, Zuazu JR, Tsakiris P, Elsakka AM, Zudaire JJ, Laguna MP, et al. Prognostic factors and percutaneous nephrolithotomy morbidity: A multivariate analysis of a contemporary series using the Clavien classification. J Urol 2008;180:2489-93.  Back to cited text no. 6
Jackman SV, Docimo SG, Cadeddu JA, Bishoff JT, Kavoussi LR, Jarrett TW, et al. The “Miniperc” technique: A less invasive alternative to percutaneous nephrolithotomy. World J Urol 1998;16:371-4.  Back to cited text no. 7
Monga M, Oglevie S. Minipercutaneous nephrolithotomy. J Endourol 2000;14:419-21.  Back to cited text no. 8
Lahme S, Bichler KH, Strohmaier WL, Götz T. Minimally invasive PCNL in patients with renal pelvic and calyceal stones. Eur Urol 2001;40:619-24.  Back to cited text no. 9
Knoll T, Wezel F, Michel MS, Honeck P, Wendt-Nordahl G. Do patients benefit from miniaturized tubeless percutaneous nephrolithotomy? A comparative prospective study. J Endourol 2010;24:1075-9.  Back to cited text no. 10
Li LY, Gao X, Yang M, Li JF, Zhang HB, Xu WF, et al. Does a smaller tract in percutaneous nephrolithotomy contribute to less invasiveness? A prospective comparative study. Urology 2010;75:56-61.  Back to cited text no. 11
Srivastava A, Chipde SS. Management of 1-2 cm renal stones. Indian J Urol 2013;29:195-9.  Back to cited text no. 12
[PUBMED]  [Full text]  
Proietti S, Giusti G, Desai M, Ganpule AP. A critical review of miniaturised percutaneous nephrolithotomy: Is smaller better? Eur Urol Focus 2017;3:56-61.  Back to cited text no. 13
Türk C, Knoll T, Petrik A, Sarica K, Skolarikos A, Straub M, et al. Guidelines on Urolithiasis. European Urological Association; 2016. Available from: https://www.uroweb.org/wp-content/uploads/EAU-Guidelines-Urolithiasis-2016-1.pdf. [Last accessed on 2018 Jan 31].  Back to cited text no. 14
Mishra S, Sharma R, Garg C, Kurien A, Sabnis R, Desai M, et al. Prospective comparative study of Miniperc and standard PNL for treatment of 1 to 2 cm size renal stone. BJU Int 2011;108:896-9.  Back to cited text no. 15
Ruhayel Y, Tepeler A, Dabestani S, MacLennan S, Petřík A, Sarica K, et al. Tract sizes in miniaturized percutaneous nephrolithotomy: A systematic review from the European association of urology urolithiasis guidelines panel. Eur Urol 2017;72:220-35.  Back to cited text no. 16
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Karatag T, Tepeler A, Silay MS, Bodakci MN, Buldu I, Daggulli M, et al. A comparison of 2 percutaneous nephrolithotomy techniques for the treatment of pediatric kidney stones of sizes 10-20 mm: Microperc vs. Miniperc. Urology 2015;85:1015-8.  Back to cited text no. 18
Gaber A, Riccardo G, Rosa M, Micali S, Keheila M, Abdelhafez M, et al. Microperc versus Miniperc for the management of medium-sized renal stones: A comparative multicenter clinical study. J Urol 2016;195:e254-5.  Back to cited text no. 19
Tepeler A, Akman T, Silay MS, Akcay M, Ersoz C, Kalkan S, et al. Comparison of intrarenal pelvic pressure during micro-percutaneous nephrolithotomy and conventional percutaneous nephrolithotomy. Urolithiasis 2014;42:275-9.  Back to cited text no. 20
Lu Y, Ping JG, Zhao XJ, Hu LK, Pu JX. Randomized prospective trial of tubeless versus conventional minimally invasive percutaneous nephrolithotomy. World J Urol 2013;31:1303-7.  Back to cited text no. 21
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Zhong Q, Zheng C, Mo J, Piao Y, Zhou Y, Jiang Q, et al. Total tubeless versus standard percutaneous nephrolithotomy: A meta-analysis. J Endourol 2013;27:420-6.  Back to cited text no. 23


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1], [Table 2]


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