Mini-Endoscopic Combined Intrarenal Surgery vs Percutaneous Nephrolithotomy in the Management of Complex Nephrolithiasis: A Randomized Controlled Trial

Abstract

Objective:

To evaluate mini-endoscopic combined intrarenal surgery (mECIRS) vs percutaneous nephrolithotomy (PCNL) in managing complex renal stones.

Material and Methods:

A randomized controlled study was conducted at our tertiary center between July 2022 and July 2024, involving 100 patients with complex renal stones who were randomly allocated for PCNL or mECIRS. The stone burden was determined based on Guy’s score using a non-contrast computed tomography of the urinary tract; patients with Guy’s Stone Score of III or IV were included in our study. Our primary objective was to assess grade A single session stone-free rate (SS-SFR) in both procedures after 1 month, defined as no stone residual after a single session procedure. Secondary outcomes included grade A (≤2 mm residual), Grade C (2.1–4 mm residual), and overall SFRs, complication rates (per Clavien-Dindo classification), operative time, fluoroscopy time, hospital stay, and overall cost.

Results:

Patient and stone characteristics were similar in both groups. Grade A SS-SFR revealed a statistically significant difference in favor of the mECIRS group compared with the PCNL group (51% vs 32.6%, respectively, p-value = 0.0275). However, the final grade A SFR after auxiliary procedures was comparable (40.8% for the PCNL group compared with 51% for the ECIRS group, p-value = 0.557). The mECIRS showed a less operative and fluoroscopy time. The complication rate was 38.77% vs 14.28% in the PCNL and mECIRS, respectively, where it was higher in the former, with a statistically significant value (p-value = 0.006). The mECIRS group experienced shorter hospital stay and comparable cost-effectiveness.

Conclusion:

mECIRS is effective and safe in managing patients with complex renal stones in a single session with fewer comorbidities than standard PCNL.

The study was registered at Clinicaltrial.gov with a registration number: NCT06085794.

Introduction

Complex nephrolithiasis, encompassing multiple calyceal or branched staghorn renal stones, remains a significant challenge for urological surgeons striving to attain stone-free status and reduce complication rates.¹

Percutaneous nephrolithotomy (PCNL) is the preferred treatment for significant renal stone burdens, although flexible ureteroscopy (FURS) has recently been used as an alternative. Achieving a high stone-free rate (SFR) requires complete access to the entire intrarenal pelvicalyceal system, which is crucial for treating complex calculi. However, achieving this goal can be technically challenging with FURS or PCNL alone.^1,2

PCNL often requires other auxiliary procedures such as redo PCNL, FURS, or ESWL to achieve a higher SFR for complex renal calculi.² Multiple tracts of PCNL can be used to manage a substantial stone burden; however, it requires a high level of expertise and is associated with increased parenchymal injury, blood loss, and other comorbidities.^3,4

Mini-endoscopic combined intrarenal surgery (mECIRS) utilizes both FURS and Mini-PCNL techniques simultaneously to improve access to the pelvicalyceal system (PCS) while minimizing the number of percutaneous access tracts. This approach aims to enhance stone clearance with reduced morbidity in treating complex renal calculi. However, ECIRS necessitates at least two skilled endoscopic surgeons, and it can be challenging to execute because of the learning curve and associated costs.^4
–6

Because of the lack of data investigating mECIRS in managing complex renal stones, there is a clear demand for further evaluation. We designed our study to assess the safety, efficacy, and cost-effectiveness of PCNL and mECIRS for managing complex renal stones.

Patients and Methods

A randomized controlled study was conducted at our tertiary center after approval from the local ethics committee. Patients aged 18 and older who presented to our urology clinic with complex renal stones between July 2022 and July 2024 were included in our study after obtaining written informed consent. The stone burden was determined according to Guy’s score assessed by non-contrast computed tomography of the urinary tract (NCCT). Patients with a Guy’s Stone Score (GSS) of III or IV were included in our study.

The study was approved by the Research Ethics Committee of the Faculty of Medicine, Ain Shams University, Cairo, Egypt (FWA000017585) with ethical approval number: MD 133/2022.

We excluded patients with congenital renal anomalies, a single kidney, urinary tract infections, coagulation disorders, and lumbar hernias, as well as those who were pregnant or had cardiovascular or pulmonary issues, from our study.

Patients were randomized with a computer-based allocation into two equal groups at a ratio of 1:1. Group A consists of patients scheduled for PCNL, while group B consists of patients scheduled for mECIRS. The primary investigator who performed the procedure was not involved in recruiting or randomizing patients. Investigators who collected data and conducted statistical analysis were blinded to the type of procedure performed.

All patients received a comprehensive preoperative evaluation, which included their medical history, a thorough examination, laboratory assessments, radiographical evaluations, and an assessment of surgical fitness. Stone burden assessment was performed using NCCT by the ellipsoid formula, number and density of stones, and to calculate GSS. Urinary tract infections were treated before the operation.

Surgical technique and postoperative management

For group A, PCNL was performed in the prone position. As it is the standard practice in our center, with advantages in access and maneuverability. Depending on the stone configuration, one or more tracts were used to access the PCS to facilitate maximum stone extraction if a single tract was not sufficient. In all tracts, a standard-sized tract was used. A 26-F Nephroscope (Karl Storz Endoscopy, Tuttlingen, Germany) was utilized in group A, along with a 30 Fr sheath. The stones were disintegrated using pneumatic lithotripsy (Swiss Lithoclast Master). After the procedure, a DJ stent was inserted, and a 16-F nephrostomy tube was fixed for one day unless complications occurred.

For the mECIRS group, patients were placed in the Galdakao-modified supine Valdivia position (GMSV).⁷ A 9.5 Fr disposable flexible ureteroscope (URS), LithoVue (Boston Scientific, Marlborough, MA, USA), was utilized through a 13/11 access sheath (Cook, Blooming, USA) for endoscopic laser stone lithotripsy. Concurrently, under fluoroscopic and endoscopic visualization guidance, a percutaneous puncture was performed in the designated calyx, establishing a 15–16 Fr percutaneous tract utilizing a single-step metal dilator. The second surgeon employed a 12 Fr Karl Storz MIP M Percutaneous Nephroscope.

The primary stone burden was fragmented using laser lithotripsy with a 500 μm holmium laser fiber and 2.5–3 J of energy at a frequency of 15 Hz. For stones that were not accessible, a flexible URS and nitinol zero-tip Dormia were employed to maneuver the stone into position for the nephroscope’s “pass-the-ball maneuver.” Stones that were too large to be managed by Dormia were initially fragmented using a laser with either a 365 or 200 μm fiber to a smaller size with the flexible URS. At the end of the procedure, a DJ stent and a 12 Fr nephrostomy tube were placed for 1 day unless complications occurred.

For the PCNL group, procedures were performed by a single surgeon with an assistant. In the mECIRS group, two surgeons worked simultaneously—one performing retrograde FURS and the other handling percutaneous nephroscopy—reflecting the procedural requirements of mECIRS. The same team of surgeons was involved in both study arms to ensure consistency in expertise.

Operative time was recorded from patient positioning until urethral catheter insertion at the end of the procedure. Fluoroscopy time was recorded in both procedures. Perioperative complications up to one month postoperatively were reported according to the modified Clavien-Dindo classification.⁸ Postoperative pain was assessed using the visual analog scale (VAS), ranging from 0 (no pain) to 10 (worst possible pain), recorded at 24- and 48-hours postprocedure. Hemoglobin drop was calculated as the difference between preoperative hemoglobin levels (measured within 24 hours before operation) and postoperative hemoglobin levels (measured within 24 hours after operation), expressed in grams per deciliter (g/dL).

One month after the procedure, the DJ stent was removed from all our patients after an evaluation for any residual stones based on NCCT. Once the patient was confirmed stone free and no additional procedure was required, stent removal was scheduled. Our primary outcome was to assess grade A single session SFR (SS-SFR) for each technique, which is defined as no stones being visualized on NCCT after a single session procedure, grade B: relative stone free (<or = 2 mm fragments), grade C relative stone free (2.1–4 mm fragments), overall SFR complication rates, operative time, fluoroscopy time, hospital stay, and cost were considered as secondary outcomes. We documented and reported the percent reduction in stone volume in non-stone-free patients as well as any extracorporeal shock wave lithotripsy (ESWL), chemo-dissolution, or repeat operation required for managing residual stones.

Cost analysis was conducted in U.S. dollars (USD) and reported as the average cost per patient in each group. Total procedural costs included expenses for surgical instruments, operating room time, and anesthesia. Postoperative care costs encompassed medications and nursing care, whereas hospital stay costs were calculated based on the per-day rate at our institution. Auxiliary procedure costs were determined as the mean cost of additional interventions (e.g., FURS, ESWL, or chemo-dissolution) required for patients with residual stones, averaged across all patients in each group. Costs were derived from hospital financial records

Sample size calculation

It was calculated by the community medicine department by a separate member not involved in the study. It was done using the PASS 11 program. The sample size was calculated based on the SFRs reported by Zhao et al. (2021),⁶ which showed an SS-SFR of 88% for ECIRS and 66.6% for mPCNL, a difference of 21.4%. Using this effect size, a sample size of at least 50 patients per group was determined to detect a similar difference with 80% power, a 95% confidence level, and a margin of error of ±0.15. Based on their SFR, a sample size of at least 50 patients in each group was sufficient to achieve the study’s primary objective.

Statistical analysis

Data interpretation was done using SPSS package version number 20. Quantitative data were tested for normality with the Shapiro-Wilk test and described as mean and standard deviation (± standard deviation [SD]). A Student’s t-test was used to compare quantitative variables between the two study groups. Chi-square and Fisher’s exact tests were used to test the association between qualitative variables. p-Value ≤0.05 was considered significant.

Results

In our study, out of 100 enrolled patients, 49 patients in each group completed their follow-up, as illustrated in Fig. 1. Both groups had no significant differences regarding patients’ characteristics and preoperative parameters. The mean stone size was 4.4 ± 0.3 cm for the PCNL group and 4.1 ± 0.6 cm for the mECIRS group (Table 1).

FIG. 1.

Consort flow diagram.

Table 1.

Demographic Data and Preoperative Parameters

	Group				p-Value
	PCNL (n = 49)		ECIRS (n = 49)
	Mean	±SD	Mean	±SD
Age	43.00	9.33	42.00	8.60	0.642
BMI	34.33	2.50	33.41	2.86	0.675
Gender
Man	23 (46.9%)		31 (63.3%)		0.104
Woman	26 (53.1%)		18 (36.7%)		0.104
Laterality
Right	23 (46.9%)		23 (46.9%)		0.232
Left	26 (53.1%)		26 (53.1%)		0.232
Symptom presentation
Accidentally discovered	15 (30.6%)		13 (26.5%)		0.653
Loin pain	20 (40.8%)		23 (46.9%)		0.545
Fever	4 (8.2%)		5 (10.2%)		1
hematuria	10 (20.8%)		8 (16.3%)		0.614
Comorbidity
DM	7 (14.3%)		2 (4.1%)		0.159
HTN	10 (20.4%)		12 (24.5%)		0.628
Previous stone operation in the affected kidney	15 (30.6%)		10 (20.4%)		0.247
Guy score
G3	26 (53%)		25 (51%)		0.479
G4	23 (47%)		24 (49%)		0.479
Maximum Stone size (cm)	4.4	0.258	4.12	0.57	0.37
Stone burden (cm³)	30.88	12.22	31.41	10.99	0.82
Mean CT density (HU)	1043.7	36.2	1121.1	94.6	<0.001

BMI = body mass index; CT = computed tomography; DM = diabetes mellitus; ECIRS = endoscopic combined intrarenal surgery; HTN = hypertension; HU = Hounsfield units; PCNL = percutaneous nephrolithotomy; SD = standard deviation.

Grade A SS-SFR revealed a statistically significant difference in favor of the mECIRS group compared with the PCNL group (51% vs 32.6%, respectively, p-value = 0.0653). The stone-free rates (SFR) for grades B, C, and overall SFR were 34.7%, 10.2%, and 96%, respectively, in the mECIRS group, compared to 38.8%, 8.2%, and 79.6%, respectively, in the PCNL group.

The percentage of reduction in stone volume was 83.3 ± 6.2% in the mECIRS group and 77.5 ± 10.1% in the PCNL group. The final stone-free rate (SFR) after auxiliary procedures showed no statistically significant difference between the groups: 98% in the mECIRS group versus 96% in the PCNL group (P-value = 0.557). Regarding SFR grading (A, B, and C), was as follows: 51%, 36.7%, and 10.2% in the mECIRS group and 40.6%, 44.9%, and 10.2% in the PCNL group, respectively (Table 2).

Table 2.

Perioperative Data

	Group				p-value
	PCNL (n = 49)		ECIRS (n = 49)
	Mean	±SD	Mean	±SD
Operation time (minute)	119.67	12.95	113.32	15.44	0.0298
Fluoroscopy time (second)	165.2	18.3	113.6	22.2	<0.001
No. of percutaneous access tracts					<0.0237
One tract	26		49
Multiple tracts
two	20		0
three	3		0
Pain visual analog scale score
At 24 hours	6.4	2.3	4.2	1.1	<0.001
At 48 hours	2.6	1.4	2.2	1.2	0.1322
Hemoglobin drop (g/dL)	3.02	1.30	2.47	1.08	0.025
Single session SFR
Grade A (absolute stone free)	16 (32.6%)		25 (51%)		0.0653
Grade B (≤2 mm residual)	19 (38.8%)		17 (34.7%)		0.675
Grade C (2.1–4 mm residual)	4 (8.2%)		5 (10.2%)		0.726
Total	39 (79.6%)		47 (96%)		0.0275
Percent reduction in stone volume	77.5%	10.06	83.33%	6.23	0.3702
Significant residual stones of more than 4 mm	10 (20.4%)		2 (4.0%)		0.0275
Auxiliary procedures
Flexible URS	4		0		0.0275
ESWL	4		2
Chemo-dissolution	2		0
Final SFR
Grade A (absolute stone free)	20 (40.8%)		25 (51%)		0.310
Grade B (≤2 mm residual)	22 (44.9%)		18 (36.7%)		0.411
Grade C (2.1–4 mm residual)	5 (10.2%)		5 (10.2%)		1
Total	47 (96%)		48 (98%)		0.557
Hospital stay (days)	2.60	1.43	1.57	0.87	<0.001
Clavien-Dindo classification
Grade I
Postoperative fever (>38°C)	6	12.3%	2	4.1%
Urinary leakage	2	4.1%	1	2.0%
Postoperative IV narcotics use	4	8.16%	2	4.1%
Total grade I	12	24.5%	5	10.2%
Grade II
Blood transfusion	4	8.16%	1	2..0%
Total grade II	4	8.16%	1	2.0%
Grade IIIA
Perirenal abscess	1	2.0%	0	0.0%
Urosepsis without organ dysfunction	2	4.1%	1	2.0%
Grade IIIB	0		0
Total grade III	3	6.1%	1	2.0%
Grade IV
Grade V
Complication rate	19	38.77%	7	14.28%	0.006

ESWL = extracorporeal shock wave lithotripsy; SFR = stone-free rate; URS = ureteroscope.

Perioperative parameters are shown in Table 2. There is a statistically significant difference between the two study groups regarding operative time. The mean operative time was 119.67 and 113.32 minutes in the PCNL group and mECIRS, respectively (p-value 0.029). mECIRS demonstrated shorter operative and fluoroscopy times, showing a statistically significant difference.

The complication rate was 38.77% for the PCNL group, compared with 14.28% for the mECIRS group; this difference was statistically significant (p-value = 0.006). The Hb drop rate was more pronounced in the PCNL group, which also had a higher incidence of blood transfusions. Additionally, postoperative pain, analgesic requirements, and hospital stays were lower in the mECIRS group compared with the PCNL group, as shown in Table 2.

An analysis of the average operational costs, postoperative care, medications, and hospital stays in both groups was conducted. The total cost of the initial intervention was higher in the mECIRS group compared with the PCNL group ($1094 vs $824). The costs of the auxiliary procedures were $100 in the mECIRS group and $337 in the PCNL group, respectively. The overall cost of treating patients with complex renal stones was comparable in both groups, averaging $1194 for the mECIRS group and $1161 for the PCNL group (Table 3).

Table 3.

Cost Analysis

Cost analysis	PCNL	ECRIS
Total procedural cost	645$	1014$
Average postoperative care	37$	20$
Average hospital stay cost	142$	60$
Total hospital cost	824$	1094$
Auxiliary procedures cost (mean)	337$	100$
Total cost including auxiliary procedure costs	1161$	1194$

Discussion

Patients with a high stone burden and complexity often have a reduced SFR and increased postoperative complications. PCNL remains the standard approach for treating these complex cases. However, the rigidity of nephroscopy made navigating the PCS very challenging, hindering proper stone management. Consequently, this resulted in a higher postoperative stone residual, along with the considerable morbidity associated with the large access sheath and multiple tracts.^3,9

ECIRS has helped minimize access tracts and improve the one-step SFR. During the procedure, the FURS, which can easily navigate the PCS, addresses torque issues caused by the nephroscope while searching for inaccessible stones. Implementing mini-PCNL in this setting is a more recent approach to reducing procedure morbidity. Only a few descriptive or comparative trials have been published assessing mECRIS, especially in treating multi-calyceal stones.¹⁰ The GMSV position employed in mECIRS enhances the drainage of the PCS while facilitating the removal of stone fragments. Furthermore, it provides advantages during anesthesia by mitigating body compression, especially in patients who are obese or elderly^6,11

–15

Grade A as well as overall SS-SFR demonstrated a statistically significant difference favoring the mECIRS group compared with the PCNL group (51% and 96% vs 32.6% and 79.6%, respectively; p-value = 0.0275). The auxiliary procedures required were documented in 10 cases of the PCNL group (four cases underwent FURS, four cases underwent ESWL, and two cases needed chemo-dissolution), compared with two cases in the mECIRS group that had an ESWL session.

Zhao et al. reported comparable results, showing an (SS-SFR) of 88% in the ECRIS groups compared with 66.6% in the m-PCNL group, with a statistically significant difference (p-value = 0.003).⁶ Hamamoto et al. also reported similar results in their study involving 161 patients, where the SFR for mini-ECIRS was significantly higher than that of the other procedures (mPCNL and conventional PCNL) (SFR = 81.7%, 38.9%, and 45.1%, respectively; p < 0.001) following auxiliary treatment, the SFR was 86.7%, 61.1%, and 61.0%, respectively; p = 0.002).⁴ Khadgi et al. studied 153 patients; 70 underwent standard PCNL, and 83 underwent mini-PCNL. The stone-free rates of PCNL monotherapy were comparable for both groups (83% for mini-PCNL and 88.6% for standard-PCNL, P-vaule = 0.339). These results were comparable to our results in the PCNL arm.¹⁶

According to GSS, Rico et al. assessed the mECIRS technique in patients with a high stone burden. They found an SFR of 93.8% for GSS 3 and 25% for GSS 4, with 11 patients making up 18% of the study group.¹³ On the contrary, Chen et al. conducted a study of 34 patients evaluating mECIRS and mPCNL, where there was no statistically significant difference between both groups regarding SS-SFR and overall final SFR.¹⁷

The better SS-SFR recorded in our trial may be attributed to the synergistic effect of the flexible URS, which pulls large stone fragments from different calyces into a position that enables the mPCNL to disintegrate and remove them efficiently. Additionally, the supine position facilitates dependent drainage of the system with the “fragments” washout.

In our study, mECIRS demonstrated a shorter operative time of 113.3 minutes compared with 119.7 minutes for PCNL. Although this difference is statistically significant, it is clinically insignificant and mainly due to the time required to position the patient prone rather than the actual handling of stones. Other research by Chen et al. and Zhao et al. also found no statistically significant difference in operative time.^6,17

The fluoroscopy time was significantly longer in the PCNL group than in the mECIRS group. This difference may be due to the time taken to establish multiple tracts and search for residual stones at the end of the procedure in the PCNL group.

In our study, the complication rates were 38.8% for the PCNL group and 14.3% for the mECIRS group. Most complications were classified as Clavien-Dindo grade 1. Only three cases of a grade 3A complication were recorded in the PCNL group and one case in the mECIRS group, which involved one case of perinephric abscess that required percutaneous drainage and antibiotic treatment in the PCNL group, while the other three cases were patients diagnosed with urosepsis without organ dysfunction. We did not record any visceral injuries in either group.

The rate of Hb drop was more significant in the PCNL group, which had a higher incidence of blood transfusions. This could be attributed to the multiple-tract PCNL, increased torque on the kidney, and excessive manipulation to manage the stones, which results in more renal injuries compared with the mini-endoscopic tract used in the other group procedure.

Zhao et al. reported a comparable complication rate in the ECIRS and mPCNL groups, with incidences of 7.5% and 16%, respectively. Three percent of these complications were classified as grade 3 according to the Clavien-Dindo classification.⁶ In addition, Khadgi et al. reported similar results as regards incidence (12% vs 24.3%, p = 0.048) and severity of complications, which were significantly lower with mini-PCNL compared with standard PCNL (p = 0.031). Standard PCNL was associated with an increased rate of blood transfusion (12.9% vs 2.4%, p = 0.013) and a significant decrease in hemoglobin (p = 0.018).¹⁵ Hamamoto et al., Chen et al., and Rico et al. also reported similar results.^4,13,17

Postoperative pain (as measured by VAS scores) and the need for IV narcotics (8.16% in PCNL vs 4.1% in mECIRS) were lower in the mECIRS group, likely due to the smaller single tract used compared with the larger multiple tracts in the PCNL group.

Even if two urologists are required to perform the mECIRS procedure and additional surgical equipment is necessary, mECIRS is still likely to offer a cost benefit to the healthcare system. The initial cost was higher for the mECIRS group than for the PCNL group; however, by the end of our study, the final overall cost was comparable. Although the mECRIS patient group initially incurred higher costs, the reduced surgical complications, shorter hospital stays, and decreased need for additional procedures to address residual stones ultimately lowered the overall cost.

The technique presented in our study, which combines mPCNL with a retrograde flexible URS, utilizes fewer percutaneous tracts, achieves a higher SS-SFR, and results in a lower complication rate. This study demonstrated the resilience of mECIRS in modern renal stone management, as it is the first prospective comparative study, to our knowledge, that compares mECIRS to PCNL and includes a cost analysis evaluation.

However, our study has some limitations: First, it was a single-center study involving a limited number of patients. More studies with a larger number of patients are needed. Second, PCNL was performed in the prone position using a regular-size sheath, in contrast to the supine position with a small sheath utilized in the mECRIS group, which may have influenced the SFR and incidence of complications. Finally, our study primarily focused on clinical and surgical outcomes. However, patient-reported outcome measures (PROMs) in evaluating patient-centered results were not evaluated. Future studies should incorporate PROMs to better assess quality-of-life outcomes and patient satisfaction across different surgical approaches.¹⁸

While mECIRS demonstrated a higher SS-SFR and lower complication rates, the final SFR after auxiliary procedures was comparable between the two groups, suggesting that PCNL remains a viable option for patients where mECIRS is not feasible due to resource constraints or absence of surgeon expertise in simultaneous endoscopic techniques.

Conclusion

mECIRS is an effective and safe surgical procedure for managing complex stone burdens. It offers satisfactory stone clearance in a single step with fewer complications than standard PCNL. Additionally, mECIRS demonstrates similar cost-effectiveness.

Authors’ Contributions

A.M.T.: Protocol design—literature search—results section. A.H.: Writing discussion section—final revision. M.M.E.: Data collection and analysis—results formulation. K.T.: Final revision. H.A.: Protocol design—introduction and methodology section—final revision.

Ethics Approval and Consent to Participate

The study was approved by the Research Ethics Committee of the Faculty of Medicine, Ain Shams University, Cairo, Egypt (FWA000017585) with ethical approval number: MD 133/2022.

Consent for Participation

Written consent was obtained from all patients or legal guardians before participation.

Footnotes

Availability of Data and Materials

The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request.

Author Disclosure Statement

All authors have approved the final version of this article, and there is no conflict of interest to declare. Our article has not been published previously or is under consideration for publication elsewhere.

Funding Information

No funding was received for this article.

Abbreviations Used

References

Türk

, Petřík

, Sarica

, et al. EAU guidelines on interventional treatment for urolithiasis. Eur Urol [Internet]. 2016; 69(3):475–482.

Aboumarzouk

, Monga

, Kata

, et al. Flexible Ureteroscopy and Laser Lithotripsy for Stones >2 cm: A Systematic Review and Meta-Analysis. J Endourol, 2012; 26(10):1257–1263.

El-Nahas

, Eraky

, Shokeir

, et al. Factors Affecting Stone-Free Rate and Complications of Percutaneous Nephrolithotomy for Treatment of Staghorn Stone. Urology [Internet], 2012; 79(6):1236–1241.

Hamamoto

, Yasui

, Okada

, et al. Endoscopic combined intrarenal surgery for large calculi: Simultaneous use of flexible ureteroscopy and mini-percutaneous nephrolithotomy overcomes the disadvantages of percutaneous nephrolithotomy monotherapy. J Endourol, 2014; 28(1):28–33.

Wen

, Xu

, Du

, et al. Minimally invasive percutaneous nephrolithotomy versus endoscopic combined intrarenal surgery with flexible ureteroscope for partial staghorn calculi: A randomised controlled trial. Int J Surg, 2016; 28:22–27.

Zhao

, Li

, Tang

, et al. A comparative study of endoscopic combined intrarenal surgery (ECIRS) in the galdakao-modified supine valdivia (GMSV) position and minimally invasive percutaneous nephrolithotomy for complex nephrolithiasis: A retrospective single-center study. Urolithiasis [Internet], 2021; 49(2):161–166.

Scoffone

, Cracco

, Cossu

, et al. Endoscopic Combined Intrarenal Surgery in Galdakao-Modified Supine Valdivia Position: A New Standard for Percutaneous Nephrolithotomy? Eur Urol [Internet]. 2008; 54(6):1393–1403.

De La Rosette

, Opondo

, Daels

FPJ

, et al.; CROES PCNL Study Group. Categorisation of complications and validation of the Clavien score for percutaneous nephrolithotomy. Eur Urol, 2012; 62(2):246–255.

Desai

, De Lisa

, Turna

, et al. The Clinical Research Office of the Endourological Society Percutaneous Nephrolithotomy Global Study: Staghorn Versus Nonstaghorn Stones. J Endourol [Internet]. 2011; 25(8):1263–1268.

10.

Moon

, Cho

, Jung

, et al. The Consecutive 200 Cases of Endoscopic-Combined Intrarenal Surgery: Comparison between Standard and Miniature Surgeries. Medicina (Kaunas), 2023; 59(11):1971.

11.

Abdullatif

, Sur

, Abdullatif

, et al. The safety and efficacy of endoscopic combined intrarenal surgery (ECIRS) versus percutaneous nephrolithotomy (PCNL): A systematic review and meta-analysis. Adv Urol, 2022; 2022:1716554.

12.

, Du

, Xuan

, et al. The efficacy and safety of one-stage endoscopy combined with intrarenal surgery (mini-nephrostomy tract) in the prone split-leg position for complex renal calculi. Curr Urol, 2023; 17(1):13–17.

13.

Rico

, Blas

, Javier

, et al. Mini-endoscopic combined intrarenal surgery (mini-ECIRS) for complex urolithiasis. World J Urol, 2024; 43(1):23.

14.

Scoffone

, Cracco

. Invited review: The tale of ECIRS (Endoscopic Combined IntraRenal Surgery) in the Galdakao-modified supine Valdivia position. Urolithiasis [Internet], 2018; 46(1):115–123.

15.

Tawfeek

, Elmoazen

, Saafan

, et al. Simultaneous antegrade and retrograde endourological approach in Galdakao-modified supine Valdivia position for the management of missed stents associated with complex renal stones: A non-randomized pilot study. Int Urol Nephrol, 2021; 53(2):211–217.

16.

Khadgi

, El-Nahas

, El-Shazly

, et al. Comparison of standard- and mini-percutaneous nephrolithotomy for staghorn stones. Arab J Urol [Internet]. 2021; 19(2):147–151.

17.

Chen

Z-H

, Lee

K-H

, Tseng

W-H

, et al. Comparison of mini endoscopic combined intrarenal surgery and multitract minimally invasive percutaneous nephrolithotomy specifically for kidney staghorn stones: A single-centre experience. BMC Urol, 2022; 22(1):93.

18.

Mehmi

, Jones

, Somani

. Current status and role of patient-reported outcome measures (PROMs) in endourology. Urology, 2021; 148:26–31.