Simultaneous retrograde intrarenal surgery for ipsilateral asymptomatic renal stones in patients with ureteroscopic symptomatic ureteral stone removal
Lai et al. BMC Urology
Simultaneous retrograde intrarenal surgery for ipsilateral asymptomatic renal stones in patients with ureteroscopic symptomatic ureteral stone removal
Dehui Lai 0 1
Meiling Chen 1
Yongzhong He 1
Xun Li 0 1
0 Translational Medical Center, Minimally Invasive Technology and Product, Guangzhou Medical University , Guangzhou, Guangdong , China
1 Urology Department, Fifth Affiliated Hospital, Guangzhou Medical University , 621 Gangwan Road, Huangpu District, Guangzhou, Guangdong 510700 , China
Background: Ipsilateral asymptomatic renal stone associated with symptomatic ureteral stone is not a rare event, and the recommended treatment policy was not declared clearly. This study was conducted to compare the outcomes of simultaneous retrograde intrarenal surgery (RIRS) and ureteroscopy to ureteroscopy alone for this clinical event. Methods: 415 patients with symptomatic ureteral stone and ipsilateral asymptomatic renal stones were reviewed to obtain two match groups, who were treating with simultaneous modality (group A, N = 72), or ureteroscopy alone (group B, N = 72). Matching criteria were ureteral and renal stone side, duration and location, the presence of pre-stented. Perioperative and postoperative characteristics were compared between the two groups. Results: Mean stone burdens were similar between group A and B. Mean operative duration for group A and B were 72.4 21.3 and 36.4 10.2 min, respectively (P < 0.001). Mean hospital duration was 6.4 2.9 and 5.3 2.1 days in group A and B, respectively (P = 0.521). Ureteral SFR was 100% in each group. Renal SFR for RIRS was 86.1%. Complication rates in group A were higher (22.2% vs 13.9%), but the differences were not statistically significant (P = 0.358). In group A, complications were significantly less in pre-stented patients (3/25 vs 5/11, P = 0.04). Auxiliary treatment rate was significant higher in group B (69.4% vs 5.6%, P < 0.001) during follow-up (mean >18 months). Conclusions: Simultaneous RIRS for ipsilateral asymptomatic renal stones in patients with ureteroscopic symptomatic ureteral stone removal can be performed safely and effectively. It promises a high SFR with lower auxiliary treatment rate, and does not lengthen hospital duration and increase complications.
Retrograde intrarenal surgery; Asymptomatic renal stone; Simultaneous treatment
Asymptomatic renal stones are common in urological
patients. They would be symptomatic without a complete
retrieval at a certain time and required surgical treatment
. Although the current recommended method is active
surveillance with an option for 23 years in EUA
guidelines, it will be associated with a higher risk of surgical
intervention [2,3]. Ipsilateral asymptomatic renal stone
associated with symptomatic ureteral stone is not a rare
event, and the recommended treatment policy was not
declared clearly in any guidelines, especially in patients
who had already removed symptomatic ureteral stone by
Retrograde intrarenal surgery (RIRS) is rapidly popular,
benefited from the advance in flexible ureteroscopic
instrumentation and holmium laser lithotripsy. It had been
reported as an effective and definitive therapeutic option
for patients with small to mid-size renal stones [4-6]. It
is also recommended in some endourological centers for
its high stone free rate (SFR) and low complications,
when comparing with shock wave lithotripsy (SWL) and
percutaneous nephrolithotomy (PCNL) in treating renal
stones in size of <2 cm [4,7-9]. Although a high success
rate has been showed independently for endoscopic
treatment of ureteral and renal stones, there are few reports in
the literature on simultaneous RIRS for asymptomatic
renal stones in patients with ipsilateral ureteroscopic
symptomatic ureteral stone removal.
The aim of this study was to evaluate the effectiveness
and associated complications of this policy.
We obtained approval for this study from the ethics
committee of the fifth affiliated hospital of Guangzhou
Medical University. Written informed consent was
obtained from all the participants. This study was designed
as a retrospective controlled study, approved by our
hospital review board. The computerized files of 415
patients with ipsilateral symptomatic ureteral stone and
asymptomatic renal stones between March 2009 and July
2013 were reviewed and a database was constructed. 72
patients who underwent simultaneous RIRS for
ipsilateral asymptomatic renal stones after ureteroscopic
symptomatic ureteral stone removalwas defined as group
A. The matched group was 72 patients, who underwent
ureteroscopic laser lithotripsy (URL) for the
symptomatic ureteral stone alone (group B). Matching criteria
were stone side, burden and location, as well as the
presence of a pre-placed D-J stent.
Patients with congenital renal anomalies, pelvi-ureteral
junction obstruction, ureteral strictures, previous SWL
treatment, and urinary tract infection were excluded.
Ureteral and renal stone side and location were assessed
preoperatively by noncontrast spiral CT scanning. Stone
burden was defined as the surface area and calculated
according to the European Association of Urology
guidelines. Preoperative laboratory tests included blood and
urinary routine test, serum creatinine estimation, and
Prophlactic parenteral antibiotics were administrated in
all patients. Patients were placed in the lithotomy
position under continual epidural anesthesia. After
retrograde pyelography, a 0.035 inch guidewire was placed in
the upper tract. Ureter stones were treated using 8.0/9.8
French ureteroscope (Richard Wolf ). Large stones were
fragmented with holmium laser and the fragments were
removed with the stone basket or grasping devices. After
the ureteral stone was completely removed, a 12/14 F
ureteral access sheath (UAS) (COOK) was placed with
appropriate length in the patients who will undergo
RIRS. The flexible ureteroscope (7.5Fr Karl Storz Flex-X,
or 6/9.9Fr Richard Wolf Cobra) was inserted through
the guidewire to the renal pelvis. Complete inspection of
the entire collecting system was performed and small
stones were removed by nitinol basket. Large stones were
fragmented with holmium laser. Adequate stone
fragmention was considered when fragments could remove by the
stone basket or smaller than 2 mm in diameter. At the
end of the procedure, the entire collecting system was
inspected for the residual stones under the fluoroscopic
guidance and a D-J stent was left for 4 weeks.
One month after procedure, all patients were assessed
by noncontrast spiral CT to confirm the SFR. Complete
stone-free was defined as the absence of any fragments.
A visual analogue pain scale (VAS) was used to quantify
the degree of pain. Preoperative and postoperative
characteristics, complication rate, hemoglobin drop, hospital
duration, SFR, auxiliary treatment rate (ATR), medical
cost were compared between two groups. Auxiliary
treatments were defined as the treatment for managing
the residual renal stone or sever complication. Auxiliary
procedure was defined as using surgical methods in the
treatment during follow-up.
After the first follow-up evaluation, patients returned
for an assessment with urinalysis, KUB or urinary
ultrasound every 3 months during the first year and every
6 months thereafter.
Statistical analysis was done using SPSS 17.0 for
Windows. Continuous variables were compared with
student t test and Wilcoxon test, and Univariable analysis was
conducted using the Pearson2 statistic or Fishers exact
test for categorical data. Differences resulting in p < 0.05
were considered significant.
Patients demographic and preoperative characteristics
were summarized in Table 1. There were no significant
differences between two modalities. Perioperative and
Postoperative characteristics were compared in Table 2.
Mean operative duration for group A and B were 72.4
21.3 (range 42.5100) and 36.4 10.2 (range 2450)
min, respectively (P < 0.001). Mean fluoroscopy time was
significantly longer in group A (P < 0.001). Mean drop in
the postoperative hemoglobin level was 0.5 0.21 (range
0.10.7) g/dL in group A, which was found to be
statistically significant (P < 0.001) compared with the
corresponding decrease (0.2 0.11, range 0.10.4 g/dL) in
group B. However, no blood transfusion was required in
both groups. VAS was higher in group A at postoperative
6 h, 12 h and 24 h, but the difference was not statistically
significant at postoperative 24 h (P = 0.477). Mean hospital
duration was 6.4 2.9 days (range 312) in group A, and
5.3 2.1 days (range 212) in group B (P = 0.521).
Complication rates in group A were higher (22.2% vs
13.9%), but the differences were not statistically
significant (P = 0.358). Four patients in each group were
administrated by oral analgesics for post-operative pain
Table 1 Demographic data of patient
Group A (URL + RIRS)
(Clavien). Four patients had post-operative vomit (Clavien)
in group A was treated by oral antiemetic. Transient
postoperative fever was developed in four patients in each
group and could be successfully treated with antibiotics and
antipyretics (Clavien). Of group A and B, four and two,
respectively, had minor ureteral perforations (Clavien a).
They were successfully treated by D-J stent for 8 weeks
and did not have any subsequent sequelae at follow-up.
In group A, complications were significantly less in
patients with pre-procedural D-J stent placement (3/25 vs
5/11, P = 0.04). Also, ureteral perforation was only
encountered in patients without pre-procedural D-J
One-month ureteral SFR was 100% in each group. In
group A, one-month renal SFR was 86.1%. Eight failures
of RIRS were due to impossible to reach the calyx
containing stone. Residual fragments were seen in two patients,
which were passed spontaneously during follow-up.
Statistically significant was not found in stone composition
between group A and B.
Follow-up data was recorded in all patients (Table 3).
Mean follow-up time for all patients was 18.6 9.6 months
(range 1236). The ATR was significant higher in group B
(69.4% vs 5.6%, p < 0.001). In group A, two patients
underwent PCNL for renal stone, while 62 auxiliary procedures
were performed in 46 patients in group B, including URL
(n = 10), RIRS (n = 22), ESWL (n = 26), PCNL (n = 4). Of
46 patients, Four had obstructing steinstrasse after ESWL
were treated by URL, ten underwent RIRS because of
significant residual stone after ESWL and two underwent
PCNL for the renal stone due to failure in RIRS.
Therefore, mean number of procedures per patient was
significantly higher in group B (1.86 vs 1.03, p < 0.001). But
mean medical cost per patient was still higher in group A
(16431.2 3425.3 vs 13125.1 2165.4 RMB, P < 0.001).
Asymptomatic renal stone associated with ipsilateral
symptomatic ureteral stone is not a rare event [10,11].
URL has equivalent or superior results comparing with
ESWL in treating symptomatic ureteral stone. 
When encountering a coexisted ipsilateral asymptomatic
renal stone, no established guidelines are available.
Active observation, ESWL, PCNL as well as RIRS should
be discussed. Previous research had showed that active
observation will be associated with a higher risk of
Table 3 Follow-up data of patients
surgical intervention [2,3]. Patients choosing ESWL
often needed multiple sessions to achieve higher SFR
. PCNL, a favoured treatment for stone >2 cm, is
associated with higher potential risks, such as bleeding,
urosepsis, and urine leakage . Recently,
simultaneously RIRS becomes feasible in treating ipsilateral renal
stone and seems to be an attractive option. We compare
the outcomes of this simultaneous modality to URL
alone in this study.
Ureteral stone was completely removed in each group.
In simultaneous RIRS group, the overall renal SFR after
1 month was 86.1%, which was similar to that of
previous reports. Goldberg H et al. showed that patients with
pre-procedural D-J stent can achieve a higher renal SFR
(93.3% VS 71%) . However, the difference was not
found in this study. Inability to reach the lower pole
calyx may be the main reason of RIRS failure [15,16].
We observed that eight cases were due to this. Also, the
other predictive factor of renal SFR was stone size.
Grasso and Ficazzola reported that RIRS can achieved
an SFR of 82%, 71% and 65% with stone size of <1 cm,
12 cm and >2 cm, respectively . RIRS may be
required to clear a large stone by multiple procedures .
In our center, it is often performed for renal stone in size
of <2 cm, which can achieved a higher SFR in one
session. In this study, the simultaneous RIRS achieved
86.1% renal SFR for treating this size stone.
The other important results were lower ATR, while
complications were not significantly increased. The
causes of the higher ATR in URL alone group were often
stone induced (Table 3). In Streems and Glowackis
study, respectively, Patients with active observation,
more than 70% and 48.5% required treatment due to
increased stone duration or clinical symptomatic episode
in next 5 years [18,19]. Although our mean follow-up
period were >18 months, the ATR was 69.4% in URL
alone group comparing to only 5.6% in simultaneous
RIRS group. Few patients with residual stone may be
one of the reasons. And the other reason was that causes
of auxiliary treatment after RIRS were unexpected
incidents such as complications or flexible ureteroscope
damage, which is low in current reports Therefore, it is
important to emphasize the possibility of auxiliary
treatment in patients with URL alone is up to 70%, and with
simultaneous RIRS is only required in unpredictable
situation during preoperative conversation.
UAS is becoming increasingly popular worldwide
because of facilitating the access, decreasing intrarenal
pressure and protecting the scope . However, several
studies had shown that the over distention created by UAS
may induce ureteral ischemia and wall injuries . In this
study, we found that ureteral perforations were developed
in two patients in simultaneous RIRS group, who were not
pre-stented. Traxer O and Thomas A reported that D-J
prestenting significantly decreases the incidence of severe
access sheath related injuries . Moreover, overall
complications were significantly less in patients with
preprocedural D-J stent (6/50 vs 10/22, P = 0.04). Thereby, it
is wisdom to place DJ stent pre-procedurally in patients
who were planned to undergo simultaneous RIRS.
Although RIRS had minimal invasive nature, the low
morbidity was probably due to greater expertise in
highvolume RIRS center. When a surgeon is still in his
learning curve of RIRS, more attention should be paid in
performing simultaneous modality.
Beside the invasive nature of RIRS, another
disadvantage included the consumption of expensive instruments
such as fragile flexible ureteroscope, nitinol basket and
UAS. Large studies showed the need for repair flexible
ureteroscope after an average of 18 cases .
Obviously, the costs for RIRS are higher than URL. In our
study, although mean procedure per patient was
significantly more in URL alone group, the mean medical cost
per patient was still higher in simultaneous RIRS group
during follow-up (mean >18 months). Simultaneous
modality does not appear to be cost effective. However, SH
Lee et al. reported that patients benefited from
costeffectiveness when choosing RIRS simultaneously, with
respect to their health insurance system . Rencently,
repair for a new generation flexible ureteroscopes was
needed after 2022 procedures [25,26]. Moreover, flexible
ureteroscopes can have a significantly longer lifespan (10.6
vs 21.6 uses before damage), by following guidelines and
with training. . Thus, we believed that the results may
be changed with the developments of instruments,
techniques and national health insurance system.
An interesting observation from study was that
47.8% patients in URL alone group underwent ESWL.
Despite higher retreatment rates, it remains a preferred
option because of non-invasive nature and high level
of acceptance by patients and doctors. Although
Keeley FX et al. demonstrated that ESWL for small
asymptomatic renal stones does not offer any advantage to
patients in terms of SFR comparing to observation
(28% vs 17%, P = 0.06) , we found it can partly
eliminate apprehensiveness of patients, and can achieve a
higher SFR in upper pole renal stone. However, A
policy of treating asymptomatic renal stones with ESWL
may be still associated with a high risk of requiring
invasive procedures > 50% patients were required
additional URL, RIRS or even PCNL for obstructing
steinstrasse and residual stone.
The main limitation of this study is its retrospective
design. Allocation to a treatment modality depended on
the surgeons preference. We tried to overcome this
possible selection bias by comparing match groups of
patients and stones. Another limitation was the small
number of patients and a single center study. Therefore,
a prospective randomized controlled study with a larger
sample of multiple centers with a long time follow-up is
Simultaneous RIRS for ipsilateral asymptomatic renal
stones in patients with ureteroscopic symptomatic ureteral
stone removal can be performed safely and effectively.
It promises a high SFR with lower auxiliary treatment
rate, and dose not lengthen hospital duration and
Pre-procedurally Placing DJ stent in patients planned
to undergo RIRS simultaneously may reduce the
RIRS: Retrograde intrarenal surgery; URL: Ureteroscopic laser lithotripsy;
ESWL: Extracorporeal shock wave lithotripsy; PCNL: Percutaneous
nephrolithotomy; SFR: Stone free rate; ATR: Auxiliary treatment rate; UAS: Ureteral
access sheath; VAS: Visual analogue pain scale; CT: Computed tomography.
The authors declare that they have no competing interests.
Conceived and designed the experiments: DHL. Performed the experiments:
DHL, XL, YZH. Analyzed the data: DHL, MLC. Contributed reagents/materials/
analysis tools: DHL, MLC. Wrote the paper: DHL, MLC. All authors read and
approved the final manuscript.
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