Impact of surgical experience on safety and efficiency of RIRS for kidney stones
Objective:
The management of kidney stones has improved dramatically over the years, with endoscopic
techniques such as retrograde intrarenal surgery (RIRS) constituting a large portion of the
therapeutic procedures. The aim of this study was to compare the safety and the results of this
technique between stone centers with urologists with different experience.
Methods:
From March 2010 to August 2013, we conducted a prospective study including all RIRS performed
for kidney stones in 4 European centers. We divided the cases in two groups. Group 1: cases
operated by one surgeon at the top of his learning curve (>400 RIRS); Group 2: cases operated by
three surgeons in the early phase of learning curve (<100).
Demographic information, disease characteristics, and perioperative and postoperative data were
gathered. Stone free rate (SFR) was defined by clear imaging at renal tomography and/or
ultrasonography. Patients and stone data, procedure characteristics, results and safety outcomes
were analyzed and compared by descriptive statistics and multivariate analyses. Complications
were reported using the standardized Clavien system.
Results
Three hundred and fifty-one patients underwent 367 RIRS with holmium laser lithotripsy for renal
stones. Group 1 included 216 procedures while Group 2 included 151.
Both groups were similar for patient’s demographics (age:54vs53yr, BMI: 26vs27 Kg/m 2), stone
length (12,6vs13mm). Technical aspects of the procedures were similar in both groups (operative
time: 54vs74min; use of ureteral access sheath: 74%vs86%).
The operative time and the stone length represented a good predictors of favorable clinical
outcomes (SFR) independently of the groups at multivariate analysis (OR 0.989; 95% CI 0.9810.998, p <0.0138 and OR 0.949; 95% CI 0.908-0.991, p <0.0176, respectively).
SFR was slightly different between the groups:74%vs66%. However, the multivariate analysis
showed that there was not statistical difference between the 2 groups (OR 1.274; 95%CI 0.7122.278, p <0.4142). Nevertheless, the post-operative complications rate was statistically different
between the two groups 4,6vs13%. Patients operated in the Group 1 had a reduced likelihood of
post-operative complications (OR:0.344; 95% CI: 0.152;0.780, p<0.0106).
Discussion
The RIRS is a minimally invasive procedure and it is very practiced by young surgeons, with good
results in terms of stone-free rate compared to ESWL and with low complications rate compared to
PCNL. Nevertheless, to obtain good results in terms of efficacy and safety a great deal of
experience is required. This study confirms that the most experience in RIRS is necessary in order
to achieve a lower complications rate. Also the young urologist could obtain optimal results in term
of SFR.
Conclusion
Although the RIRS is a technique with a short learning curve, a long experience is necessary for
optimal results. Skilled surgeons have lower complications rate.