|Year : 2021 | Volume
| Issue : 2 | Page : 83-88
Comparative study of extracorporeal shock wave lithotripsy versus mini percutaneous nephrolithotomy for the treatment of nonlower calyceal 10–20 mm size kidney stone
Pinaki Roy, Debansu Sarkar, Vishal Jalan, Dilip Kumar Pal
Department of Urology, SSKM and IPGMER Hospital, Kolkata, West Bengal, India
|Date of Submission||01-Oct-2020|
|Date of Decision||12-Dec-2020|
|Date of Acceptance||28-Jan-2021|
|Date of Web Publication||22-Jun-2021|
Dilip Kumar Pal
Department of Urology, SSKM and IPGMER Hospital, Kolkata - 700 020, West Bengal
Source of Support: None, Conflict of Interest: None
Purpose: Urolithiasis is a common medical condition and the treatment is mainly minimally invasive methods. There exists no specific guidelines for the treatment of radio-opaque solitary non lower calyceal kidney stones of 10–20 mm in literature and no head to head study comparing both the procedures. Hence, this study was performed to have a specific guide for the treatment of such stones. Materials and Methods: This study, included all patients aged >18 years, with solitary radiopaque calculi of 10–20 mm size in upper or middle calyx or pelvis of the kidney. A total of 105 patients were assigned to receive extracorporeal shock wave lithotripsy (ESWL) or mini-percutaneous nephrolithotomy (PCNL) for treatment of stone were enrolled in the study and the results were compared in terms of retreatment, stone-free rate (SFR), and complications. Results: The SFR was statistically higher in the mini PCNL group for all locations. The SFR for the ESWL group was low after 1st session; however, it increased with multiple sessions. We had a total of 9 complications in both groups, which was statistically insignificant. Conclusion: This study showed that the mini PCNL is a viable, safe option for the treatment of 10–20 mm non lower calyceal stones, having superior SFRs compared to ESWL with statistically insignificant complications. It can be offered as first-line option for the management of such stones.
Keywords: Extracorporeal shock wave lithotripsy, kidney stones, mini percutaneous nephrolithotomy, nonlower calyceal
|How to cite this article:|
Roy P, Sarkar D, Jalan V, Pal DK. Comparative study of extracorporeal shock wave lithotripsy versus mini percutaneous nephrolithotomy for the treatment of nonlower calyceal 10–20 mm size kidney stone. Urol Sci 2021;32:83-8
|How to cite this URL:|
Roy P, Sarkar D, Jalan V, Pal DK. Comparative study of extracorporeal shock wave lithotripsy versus mini percutaneous nephrolithotomy for the treatment of nonlower calyceal 10–20 mm size kidney stone. Urol Sci [serial online] 2021 [cited 2022 May 20];32:83-8. Available from: https://www.e-urol-sci.com/text.asp?2021/32/2/83/318998
| Introduction|| |
Urolithiasis affects approximately 2%–3% of the general population. The introduction of percutaneous nephrolithotomy (PCNL) replaced open surgery as the main surgical therapy for renal stone diseases. Moreover, extracorporeal shock wave lithotripsy (ESWL) has been introduced as a different approach to further reduce the complications of any surgical intervention. Although the stone-free rate (SFR) for the ESWL procedure varies in different series, SFRs of 50%–70% and 70%–90% for lower calyceal stones and pelvic and upper calyceal stones can be achieved, respectively. However, the ESWL success rate depends on many factors, such as stone size, composition, pelvicalyceal anatomy, and so on. Moreover, associated problems of multiple sessions, partial stone clearance, need for ancillary procedures, and post-ESWL complications exist. However, PCNL is more invasive and has higher associated morbidity than ESWL. Mini-PCNL, wherein the size of the tract was reduced to 14–20 Fr, was thus introduced as a PCNL substitute with the hope of reducing the puncture-related PCNL complications.
Different guidelines are clear regarding the management of large (>20 mm) or small (<10 mm) stones. Moreover, managing 10–20 mm kidney stones remains controversial. As per the European Association of Urology (EAU) 2019 guidelines, the treatment of 10–20 mm kidney stones is either with ESWL or with endourologic intervention. Urologists are more comfortable with an endourological procedure for lower calyceal stones of 10–20 mm. However, the management of nonlower calyceal stones of this size is not standardized. After conducting extensive literature research, this study could not find any prospective study directly comparing the outcomes of ESWL with those of mini-PCNL for the treatment of radio-opaque solitary nonlower calyceal kidney stones of 10–20 mm in adults. Thus, this study compared the outcomes of ESWL with those of mini-PCNL to evaluate the efficacy and safety of the treatment of radio-opaque solitary nonlower calyceal kidney stones of 10–20 mm.
| Materials and Methods|| |
This was a prospective study that included all patients that presented in the institute from September 2017 to August 2019 with the diagnosis of solitary radiopaque renal stone in the pelvis, upper, and middle calyces. Patients with inferior calyceal or multiple stones, stone impacted at the ureteropelvic junction, associated UPJ obstruction, and patients with previous renal stone surgery or who received prior ipsilateral ESWL were excluded from the study. All patients gave written informed consent. Institutional ethical committee clearance was obtained before starting the study (IPGME&R/IEC/2018C579).
Data were reviewed using Epi Info (TM) 126.96.36.199. Descriptive statistical analysis was conducted to calculate the means with the corresponding standard deviations. The proportion test was used to find the standard normal deviation (Z) to compare the different proportions. Moreover, the Chi-square test was conducted to find the associations. The comparison of the mean between the two groups was performed by t-test. The odds ratio with a 95% confidence interval was calculated to find the risk factors. Consequently, P < 0.05 was considered statistically significant. The EAU 2019 guidelines described the SFR of 90% at all locations (i.e., P = 0.90). Thus, the number of patients required for this study was 30.86–31 with 88% power. The formula used for sample size calculation was as follows:
n = 4 pq/(L2)
Where n is the required sample size (P = 0.90), q = 1 − p, and L is the loss % (loss of information).
P = 0.90
q = 1 − 0.90 = 0.11
4 pq = 0.396
L2 = (0.12 × 0.90)2 = 0.36
n = 30.86–31
All patients were preoperatively assessed by detailed medical history; physical examination; urinalysis; urine culture; renal ultrasonography (USG); Intravenous pyelogram kidney, ureter, and bladder (KUB); and CT KUB region (in case IVP was not done before). Stone size was estimated using USG. Patients were assigned by a coin toss method after diagnosis to either receive ESWL or be subjected to mini-PCNL. Stone-free status was assessed with a USG KUB and X-ray KUB at 3 weeks after mini-PCNL. Moreover, stone-free status was assessed 3 weeks after each session following the ESWL with a maximum of three sessions. The complete stone clearance or presence of clinically insignificant residual fragments (<4 mm) 3 weeks after the final procedure was regarded as stone-free. The presence of any fragments <4 mm was considered as a residual stone needing further treatment.
Extracorporeal shock wave lithotripsy technique
ESWL was administered on an outpatient department (OPD) basis with an electromagnetic shockwave lithotripter (Dornier Compact Sigma by Dornier MedTech, Munich, Germany). All procedures were performed by a single urology resident. Pre-procedure analgesia was given with IM diclofenac sodium unless contraindicated. Patients were positioned supine with the shock head from the back. Both USG and fluoroscopy were used for the localization and monitoring of stone fragmentation. All patients received shocks at a frequency of 60/min. An average of approximately 2500–3000 shocks was targeted in all patients. Patients with insufficient fragmentation with 3000 shocks were posted for a second session later on. All patients were advised oral fluoroquinolone for 5 days along with analgesics when required post-ESWL. All patients were counseled regarding the possible complications of pain, hematuria, fever, and decreased urine output with advice to attend urology emergency if needed.
All patients were advised X-ray KUB and USG KUB 3 weeks after ESWL for stone clearance. A maximum of three sessions per patient was allowed. Moreover, the patient was subjected to the mini-PCNL/retrograde intrarenal surgery procedure in case of failure at the end of the three sessions.
Data regarding the number of shocks, energy level, tolerability, number of sessions needed, stone clearance rate, retreatment rate, and need for any ancillary procedures were recorded. Complications in the form of pain, fever, sepsis, and hematuria needing intervention were recorded.
Mini-percutaneous nephrolithotomy technique
All mini-PCNLs were done in a prone position by a single consultant. A 5 Fr open-ended ureteral catheter was introduced in the renal pelvis, left in situ, and a retrograde pyelogram was performed after the induction of general anesthesia. A Foley catheter was inserted, and a ureteric catheter was tied to the Foley. Patients were then repositioned to the prone position. The desired calyx was punctured with a Cook diamond tip 18G puncture needle under fluoroscopy guidance using either standard bull's eye or triangulation technique as required. Serial tract dilatation of up to 18 Fr was done under fluoroscopy guidance by metallic telescopic coaxial dilators (Wolf, Germany) over a metal guide rod on a 0.035″ guidewire. Amplatz sheath of 18 Fr (Cook Medical, Bloomington, IN, USA) was used in all cases. Standard 15 Fr 6° rigid mini-nephroscope (Olympus, Tokyo, Japan) along with Swiss Lithoclast master pneumatic lithotripter with 1/0.8 mm probe was used for stone fragmentation. Stone fragments were retrieved with 3 mm triprong/biprong rigid graspers along with flushing with normal saline. A double j stent was introduced in all cases once satisfactory stone clearance was achieved (fluoroscopy and rigid nephroscopy). A nephrostomy tube was not placed in any case.
Perioperative data regarding stone characteristics (number, size, and site), postoperative complications (PCs) anatomy, operative time, any intraoperative complications (such as PCs injury, hematuria, and need for blood transfusion), anesthesia complications, postoperative sepsis, postoperative hematuria needing intervention, and hospital stay were collected.
All cases were evaluated at 3 weeks postoperative, with X-ray KUB and USG KUB, before DJ stent removal. The patient was subjected to the ESWL procedure in case of clinically significant residual fragments.
| Results and Analysis|| |
No statistical difference was found between the two groups with regard to demography and stone characteristics [Table 1]. Moreover, 54 and 51 patients were present in the ESWL and mini-PCNL groups, respectively.
|Table 1: Comparison of demography, stone characteristics and stone free status between two groups|
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The SFR was significantly higher in the mini-PCNL group for all locations [Table 1]. Overall SFR was 98%. Only one patient had residual stone after mini-PCNL, subjected to ESWL, and had complete clearance.
The SFR for the ESWL group was low after the first session. However, it increased to 72% with subsequent sessions [Table 2]. SFRs were dependent on the location of the stone. The overall clearance was significantly lower post-ESWL for all locations [Table 1]. Even after the completion of 3 sessions of ESWL, 15 patients had residual stones. All of them underwent mini-PCNL with complete clearance. The mean operative time in the mini-PCNL group was 60.4 ± 17.5 min. The mean fluoroscopy time in ESWL was 45 ± 10.3 min. The mean hemoglobin drop after mini-PCNL was 0.8 ± 0.5 g%. Moreover, the mean preoperative creatinine level was 1.12 ± 0.13 mg/dL, which immediately increased to 1.28 ± 0.15 mg/dL in the postoperative period.
|Table 2: Distribution of stone free status of the patients with extracorporeal shock wave lithotripsy procedure (n=54)|
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This study had nine complications in each group, which was statistically insignificant. In the ESWL group, three patients developed ureteric colic managed with nonsteroidal anti-inflammatory drugs, five patients had post-ESWL fever managed with culture-specific antibiotic therapy (two had positive urine culture post-ESWL), and one patient developed steinstrasse managed with hydration, tamsulosin, and painkillers. All the patients were managed conservatively without the need for any hospital admission [Table 3]. However, in the mini-PCNL group, two patients suffered from significant bleeding requiring blood transfusion in the mini-PCNL group, and seven patients developed a postoperative fever managed with in-hospital treatment with antibiotics and antipyretics [Table 3]. No patients needed readmission for any PCs. This study summarized the complications as per the Clavien–Dindo classification system grading [Table 4]. No cases were excluded from the study. The mean hospital stay in the mini-PCNL group was 2 days. The mean hospital stay for patients who developed fever was 3.6 days.
|Table 3: Distribution of side effects and the patients of the two groups|
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| Discussion|| |
Nephrolithiasis is one of the most prevalent urologic diseases in Asia with a prevalence rate of approximately 1%–5%. In India, the incidence was lower than 40/100,000 in the 1960s. However, it increased dramatically in the last few decades with present rates of 930/100,000 and 442.7/100,000 in males and females, respectively.,, Nevertheless, the treatment of large and small stones at >20 and <10 mm, respectively, is defined clearly, however treatment of 10-20mm sized stone falls in the gray zone in both the American Urological Association and EAU guideline.
ESWL being an OPD/daycare treatment, mostly not needing any anesthesia, has become a commonly used, safe, and effective modality for the treatment of urinary stones. However, repeated sessions are needed for adequate stone clearance in many patients making the total duration of the treatment longer than with other approaches. The passage of stone fragments may cause ureteric colic, sometimes needing further treatment. Moreover, mini-PCNL has proven its efficacy with excellent stone clearance, although with a higher complication rate.
The effectiveness and success of the treatment were best indicated by the high SFR, the same being considered as the first end-point of this study. In the mini-PCNL group, the SFR was 98% for 51 cases. Most of the published data dealing with mini-PCNL reported success rates in the same neighborhood ranging from 83.3% to 100% with Knoll et al. reporting 96% for a stone of up to 30 mm at all locations and many others showing similar high success rates.
This study had an SFR of 97% for pelvis stones with mini-PCNL. Moreover, Kaya et al. reported a success rate of 71% with mini-PCNL for pelvis stones of up to 25 mm. Bryniarski et al. reported an 81% success rate with mini-PCNL for pelvis stones of >20 mm. Consequently, Mishra et al. reported a success rate of 96% for mini-PCNL for stones of 10–20 mm. It is clear from different studies that SFRs drastically increase with experience with the mini-PCNL technique as seen in this study. Moreover, the SFR for upper and middle calyceal stones in this study was 100%.
The published series had an SFR of 43.8%–60% in the ESWL group after the first session, which was similar to that of the present study. However, an SFR improvement was seen both in most published series and in this study with repeated sessions with different success rates that ranged between 71% and 95.8%.,, Moreover, Geraghty et al. had an SFR of 40% for nonlower calyceal stones, although this study had an SFR of 72% for the ESWL group after the three sessions. The lower SFRs could be due to the middle and upper ureter stones that were also included in the nonlower calyceal stone category. Fankhauser et al. had an SFR of 68.2% for nonlower calyceal stones of 5–20 mm, which was similar to this study. This study had an SFR of 71% for pelvic stones in the ESWL group, which was similar to that of the study by Hassan et al., in which the stone size was 20–30 mm. Kaya et al. had an SFR of 46% for renal pelvis stones of up to 25 mm. Bas et al. reported an SFR of 86% for pelvic stones of 10–20 mm. Another study by Javanmard et al. compared the ESWL and URS for pelvic stones in obese patients and had an SFR of 71% with ESWL. Consequently, Turna et al. revealed an SFR of approximately 83% for both upper and middle calyceal stones. In this study, the SFRs were 71% and 77% for upper and middle calyces, respectively, with ESWL modality. The present study had a lower success rate because all the stones in this study were in the range of 10–20 mm. However, the majority of stones in both the calyces were <10 mm in their study. Cecen et al. had an SFR of 87% with ESWL for nonlower calyceal stones. However, Marcovich and Smith described SFRs of 59%–72% and 59%–77% for upper and middle calyceal stones of <20 mm, respectively.
These wide variations in results explain that SFR in ESWL depends on many variables including stone density (Hounsfield unit), intrarenal anatomy, skin-to-stone distance, and the location and number of stone. It is a procedure having varied results in terms of success, whereas mini-PCNL is a trustworthy procedure having persistent high success rates in different studies. Consequently, the same was proven in this study where SFRs of 72%, 71%, and 77% for ESWL and 97%, 100%, and 100% for mini-PCNL procedures for the pelvis, upper, and middle calyceal stones, respectively, were found. Thus, the mini-PCNL gives very high success rates for stones in any location. Moreover, the retreatment rate for lower calyceal stone is quite high in the ESWL-treated patients and has been shown in numerous papers. However, lower calyceal stones were not included in the current study.
Regarding the safety between the two procedures, the complication rates in the mini-PCNL group were statistically insignificant compared with those in the ESWL group. This study revealed a complication rate of 17.6% in the mini-PCNL group that is comparable with the reported complication rates in literature ranging from 16% to 28%., On grading the complications as per the Clavien–Dindo grading, all the complications in the ESWL group were grade 1 and managed conservatively without the need for any intervention. Moreover, the majority of complications in the mini-PCNL group were grade 1 and grade 2 complication rate in the mini-PCNL group was 3.9%. Complications seen in the ESWL group were fever, colicky pain, and were similar with the complications mentioned by other studies in the literature., Furthermore, a study by Srivastava for the management of 1–2 cm renal stones revealed similar results in terms of efficacy and safety.
The most common complication in the mini-PCNL group was transient fever, which was also reported in a study by Taylor et al. The mean hospital stay in the mini-PCNL group was 2 days, which was comparable with that of the study by Resorlu et al. The intervention cost for the patient was nil in both groups because the study was conducted in a government institute where all procedures are free.
This study had a complication rate similar to other published series. Moreover, the complications in this study were similar to the complications seen in other studies. This study result represents a standard treatment outcome of a high-volume dedicated urology center. Thus, this head-to-head study of both the modalities performed in a center with outcomes similar to the other high-volume centers shows that the mini-PCNL has better stone clearance with increased minor complications.
This study had few limitations, such as lack of body mass index measurement, use of US and X-ray instead of CT scan for stone clearance evaluation, and no data collection on the stone composition, which may affect treatment outcome.
| Conclusion|| |
This study showed that the mini-PCNL is a viable and safe option for the treatment of 10–20 mm nonlower calyceal stones having superior SFRs compared with ESWL with slightly increased minor complications. It can be offered as a first-line option for the management of such stones provided that the patient is fit for anesthesia and ready for admission in the hospital.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]