A Comparison of Minimally Invasive Surgery Ureterolithotomy and Transurethral Lithotripsy in Combination with Retrograde Intrarenal Surgery: A Randomized Clinical Trial

Introduction

Urinary stones are common in about ten percent of the population at some stage in their lifetime worldwide (1, 2), with an estimated annual incidence rate of ureteral stones of nearly 500 per 100,000 populations (3). However, there is an increasing trend globally (4). Multiple therapeutic procedures such as extracorporeal shock wave lithotripsy (ESWL), transurethral lithotripsy (TUL), percutaneous nephrolithotripsy (PCNL), open ureterolithotomy, and laparoscopic ureterolithotomy are suggested to treat ureteral stones (5). Treatment modalities are generally selected according to stone size and location and the patient’s preferences and comorbidities (6). Nowadays, there are many alternative strategies for the treatment of ureteral stones when determining the best treatment by the minimal urological treatment philosophy (7). There is an increasing trend for use of minimally invasive management of ureteral stones due to the high rate of efficacy besides the low rate of adverse effects (8, 9). Laparoscopic removal of ureteral stones is a minimally invasive surgical method (10, 11). Treatment with the best approach of non-invasive methods in comparison with conventional methods such as TUL would result in higher patient safety and satisfaction. However, utilization of the TUL method accompanying retrograde intrarenal surgery (RIRS) may result in an increased success rate (12, 13). Accordingly, for better decision-making and selection of the best therapeutic approach, this study was carried out to compare the efficacy of minimally invasive surgical utereolithotomy (MISU) versus TUL plus RIRS in patients with ureteral stones larger than 15 mm.

Methods

The study was run under the ethics committee supervision of Tehran University of Medical Sciences after receiving the IRCT code (IRCT20190624043991N12), and All patients signed the informed consent before enrolling. In this single-blind randomized clinical trial, 90 consecutive patients with ureteral stones larger than 15 mm referring to  Sina Hospital in 2017 were enrolled. After an informed consent form was received from each patient, computed tomography (CT) scan was done, the largest stone measurement was determined and recorded, and those patients with ureteral calculi larger than 15 mm were included. The patients currently under medical therapy or other surgical approaches for stone management, those with stones smaller than 15 mm, subjects with TUL alone procedure without subsequent RIRS, and patients that were impossible to followed-up with were excluded. After exclusion, 74 patients remained for assignment.

This study was approved by the local ethical committee, and the Helsinki Declaration was respected across this clinical trial. Patients were randomly assigned to undergo minimally invasive surgical ureterolithotomy or TUL plus RIRS. Both groups received antibiotics as cefalotin with three daily doses, and after the urine culture was negative, the patients were enrolled. Then the cases with remained stones over 2 mm after treatment were recognized by imaging and the stone-free rate (SFR) was determined and compared across the groups.

Data analysis was performed among 74 subjects, including 37 patients in MISU and 37 subjects in TUL plus RIRS group. Data analysis was performed by SPSS (version 19.0) software [Statistical Procedures for Social Sciences; Chicago, Illinois, USA]. Chi-Square, Fisher, and Independent-Sample-T tests were used and were considered statistically significant if the P values were less than 0.05.

Results

The mean age (standard deviation) was 47.3 (±3.5) and 47.4 (±3.4) years in MISU and TUL plus RIRS groups, respectively (P-value = 0.89). The mean stone size (standard deviation) was 22.1 (1.2) and 22.9 (1.4) mm in MISU and TUL plus RIRS groups, respectively (P-value = 0.21). In each group, the ureteral stone was right-sided in 18 cases (48.6%).

Longer hospital stays, larger Apotel Infusions doses, and longer operation lengths were seen in the MISU group (Table 1). As shown in Figure 1, the stone-free rate was alike across the groups (P-value=1.00). Among 37 cases in the MISU group, two patients had stone migration during the operation. One was removed by ureteroscope and basket via ureteral incision site. In another patient with migration in the MISU group, a Double-J stent was placed, and ESWL was done. In TUL plus RIRS group, two cases with the remaining five mm diameter stone had spontaneous stone passage after six months. The rates of adverse effects (according to the Calvin Score System) were alike across the groups (P-value = 0.957) except for the fever with a higher rate in TUL plus RIRS group (Figure 2).

Table 1. Hospital stay, paracetamol per dose, and operation length across the groups

Figure 1. The stone-free rate across the groups.

Figure 2. Therapeutic adverse effects across the groups

Discussion

In this interventional study, the efficacy and safety of two surgical modalities for patients with ureteral stones larger than 15 mm, were compared. It was found that the laparoscopic (MISU) group had longer operations accompanied by a longer hospital stay and more analgesic consumption. The stone-free rate was alike across the groups, and complications had the same rate between the two groups except for the postoperative fever, which had a higher rate in TUL plus RIRS group. The remained stones in the MISU group required intervention to be passed from the ureter, but the stones in TUL plus RIRS were passed spontaneously.

A meta-analysis by Kallidonis et al., (14) revealed a significantly higher stone-free rate for MISU than ureteroscopic lithotripsy in large upper ureteral stones. Similarly, they reported longer operative and hospitalization times in patients under treatment with the MISU method. In a study by Falahatkar et al.,  (15) among sixty patients with ureteral stones larger than 10 mm, the stone-free rate was 95 percent and 100 percent for those under MISU and TUL groups, respectively, without a significant difference as well as our study. Also, similar to our findings, the analgesic dose was significantly lower in the TUL group.

In the study by Ozturk et al., (12), the stone-free rate was 96 percent and 79 percent for RIRS and MISU groups, respectively. In our study, these rates were 94.6 percent and 97.3 percent in TUL plus RIRS and MISU groups, respectively. The difference between our results and findings is related to the important role of urologist experience in laparoscopic procedures such as MISU. The study by Aboutaleb et al., (16) revealed a stone-free rate of 59 percent and 86 percent for ESWL and MISU in patients with ureteral stones larger than 15 mm. In their study, the complications had the same rate across the groups and our study. Feyaerts et al. also reported similarly promising results for the MISU method inpatient with proximal ureteral stones that showed a low rate of adverse effects  (17).

Conclusions

Totally according to the obtained results, it may be concluded that laparoscopic ureterolithotomy was an effective and safe surgical procedure for minimally invasive strategy when first-line therapeutic approaches were unsuccessful in patients with larger ureteral stones. However, further interventional studies with a larger sample size must attain more definite results about the best therapeutic approach for patients with large ureteral stones.

Authors' contributions

SMKA is the principal surgeon who suggests this novel method, HZ and  MHK are urologists who run the project and provide the data, and SNS wrote the manuscript. MS analyses the data. HZ and MS edited the manuscript. All authors reviewed the results and approved the final version of the manuscript.

Acknowledgments

Special thanks to the Urology Research Center (URC), Tehran University of Medical Sciences, Tehran, Iran. 

Conflict of interests

All authors claim no competing interest in this surgery case report.

Funding

There was no founding. 

Ethical Statements

 The study was performed prospectively under the Tehran University ethical committees after receiving the IRCT code (IRCT20190624043991N12). All patients signed informed consent before enrolling.

 Data availability

All data and study details will be provided by the corresponding author on request.

Abbreviations

 ESWL      Extracorporeal shock wave lithotripsy

MISU       Minimally invasive surgical ureterolithotomy

PCNL       Percutaneous nephrolithotripsy

RIRS        Retrograde intrarenal surgery

SFR          Stone free rate

TUL         Transurethral lithotripsy