Yonago Acta Medica 2022;65(2):126–131 doi: 10.33160/yam.2022.05.

002 Original Article

A Comparison Between Laparoscopic and Robot-Assisted Laparoscopic

Pyeloplasty in Patients with Ureteropelvic Junction Obstruction

Niwat Lukkanawong,* Masashi Honda,† Shogo Teraoka,† Hideto Iwamoto,† Shuichi Morizane,† Katsuya Hikita†
and Atsushi Takenaka†
*Department of Urology, Charoenkrung Pracharak Hospital, Bangkok, Thailand, and †Division of Urology, Department of Surgery,
School of Medicine, Faculty of Medicine, Tottori University, Yonago 683-8503, Japan

ABSTRACT invasive surgery (MIS) has been developed and gradu-

Background The aim of this study is to compare the ally famous and become an accepted treatment op-
results of laparoscopic pyeloplasty and robot-assisted tion with varieties procedures including endoscopic
laparoscopic pyeloplasty in patients with ureteropelvic pyelotomy, laparoscopic pyeloplasty (LP) and robot-
junction obstruction. assisted laparoscopic pyeloplasty (RALP).
Methods Between March 2008 and May 2019, the Although LP and RALP present success rates at
patients who underwent retroperitoneal laparoscopic or a level comparable to those of open surgery, these two
robotic-assisted laparoscopic pyeloplasty in our institu- procedures has provided the advantages of lower mor-
tion were retrospectively reviewed. bidity, less postoperative pain, faster recovery time and
Results Thirteen patients underwent laparoscopically, shorter hospital stays.4–7 Schuessler et al. were the first
and 12 patients underwent robotic surgery. The sig- one to do laparoscopic pyeloplasty in 1993.8 Since then,
nificant difference was found in median operative time the procedure have published its popularity. However,
between laparoscopic group (296 minutes) and robotic anastomosis of ureteropelvic procedure is still consid-
group (199 minutes) (P = 0.001). The median time for ered as a hard and challenged for LP. The procedure
drain removal in laparoscopic group was longer than demands advanced laparoscopic skill with a present of
robotic group (3 vs. 2 days, respectively, P = 0.029). steep learning curve. These are limitations for a novice
Conclusion Laparoscopic and robot-assisted laparo- surgeon with low laparoscopic surgery skill.
scopic pyeloplasty is safe and excellent success rates With high technology development of robotic-
in patients with ureteropelvic junction obstruction. assisted surgery, limitations occurred in LP surgery pro-
However, our experience study suggested that robotic cedure have been gradually demolished. The procedure
surgery improves a total operative time, decreases drain becomes less complex operative task, especially, recon-
removal time and less intraoperative blood loss than structive procedures for anastomosis suturing. These
laparoscopic approach. circumstances contribute towards the ongoing goodwill
of RALP. However, robotic system exhibits limitations
Key words laparoscopic surgery; pyeloplasty; robotic on lacking of tactile feedback sensation, wasting of
surgery docking time for setting up an assisting surgical robot
instruments and highly supportive disbursement in
In 1891, Kuster described the first successful pyeloplasty several countries.9
which has been considered the gold-standard treatment Up to date, there’s still no confirmation that RALP
for ureteropelvic junction obstruction (UPJO), with has significant impact on outcomes over LP. To explore
success rate exceeding 90% (90–100%).1–3 Later within this issue, this retrospective study aimed to compare
these two to three decades, a procedure of minimally outcomes between LP and RALP in patients with UPJO
by our single center.
Corresponding author: Masashi Honda, MD, PhD
honda@tottori-u.ac.jp MATERIALS AND METHODS
Received 2021 July 1 Design and setting
Accepted 2022 March 8
Online published 2022 April 15 The study protocol and approval to conduct this study
Abbreviations: CT, Computerized Tomography; EBL, Estimated was obtained from the local institutional research and
Blood Loss; IVP, Intravenous Pyelogram; LOH, Length of Hos- ethics Board. The medical records of all patients who
pitalization; LP, Laparoscopic Pyeloplasty; MIS, Minimally In- underwent LP or RALP due to UPJO between March
vasive surgery; RALP, Robot-assisted Laparoscopic Pyeloplasty; 2008 and May 2019 were retrospectively reviewed. All
3D, 3 Dimensional visualization; UPJ, Ureteropelvic Junction;
UPJO, Ureteropelvic Junction Obstruction; US, Ultrasonography; patients were confirmed diagnosis of UPJO by renal
UTI, Urinary Tract Infection ultrasonography (US), intravenous pyelogram (IVP)

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 Laparoscopic and robot-assisted pyeloplasty

(optional), computerized tomography (CT) scan and a working port was placed 7 cm dorsal to the camera
diuretic renogram. The indications for surgery are renal port and two ports were placed in the anterior axillary
pain, urinary tract infection (UTI), stone formation, line at the level of the iliac crest and in the subcostal
decrease renal function (split renal function < 40%), region. Following exposure of the psoas muscle and the
obstructive pattern on diuretic renogram, progressive Gerota’s fascia, the ureter was identified and mobilized
hydronephrosis on serial US examination and progres- to the ureteropelvic junction (UPJ). The stay suture was
sive loss of renal function on serial radionuclide reno- placed passed to the renal pelvis and pulled out through
grams. The LP has been previously performed in 2008 the abdominal wall. The ureter was spatulated laterally
through 2012. Since 2013 when the da Vinci® Si robotic and the stenotic segment of the UPJ was resected. A 6F
system (Intuitive Surgical, Sunnyvale, CA) arrived in ureteral stent was inserted into the ureter by antegrade
our hospital, all patients has been undergoing RALP. fashion. The anastomosis was performed with a running
The data collected from the chart review included suture using a 4–0 polydioxanone suture. The anterior
patient demographics, preoperative evaluation, peri- anastomosis was initially completed, followed by the
operative data (including total operative time, robotic posterior anastomosis with the same suture. The cross-
docking time, and robotic console time), and postopera- ing vessels were preserved by anterior transposition of
tive results. Operative time was defined from the time ureter and pyelo-reduction was performed if necessary.
of skin incision to skin closure, including docking time. If renal calculi were present, the stones were removed
Perioperative and postoperative complications were before anastomosis by laparoscopic graspers or by using
classified based on Clavien and Dindo classification.10 flexible nephroscope with a stone basket through the 12-
The degree of hydronephrosis was grade of 0 to 3 ac- mm port.
cording to Ellenbogen’s grading system.11
The primary outcome of our study was the success Robot-assisted laparoscopic pyeloplasty
rate of surgery. This was defined as relief of symptoms The transperitoneal approach was our preferred in
as well as improve obstruction on a diuretic renogram RALP. The position of the ports as shown in Fig. 1.
at 6 to 12 months after surgery. The secondary outcome A 12-mm camera port was made 6 cm lateral to the
included operative time, length of hospitalization (LOH), umbilicus by open Hasson technique. The 8-mm robotic
estimated blood loss (EBL) and complications. arm ports were placed laterally at a distance of 8 cm
from the camera port. The first assistant port was set
Surgical procedure at a distance of 6 cm from the midpoint between the
The Anderson-Hynes dismembered technique was caudal robot’s arm port and the camera port. The da
performed in all patients for both LP and RALP group. Vinci® robotic system was placed on the dorsal side of
The LP was performed retroperitoneally, whereas the the patient.
RALP was an intraperitoneal approach. All patients The operation started with colon mobilization,
were positioned in the standard flank position. The LP allowing the colon to fall medially. Gerota’s fascia was
procedures were performed by one surgeon who passed exposed. The ureter was identified and dissected up to
the Endoscopic Surgical Skill Qualification System in UPJ. The rest of the surgical steps were almost the same
Urological Laparoscopy established by the Japanese as LP, except RALP did not need to stabilize the renal
Society of Endourology and Robotics. The RALP pro- pelvis by stay sutures. Because of freedom of robotic
cedures were performed by two surgeons who passed arms, it was easy to perform anastomosis without any
the Endoscopic Surgical Skill Qualification System fixation.
in Urological Laparoscopy and Proctor Qualification
System for Urological Robotic Surgery established by Follow up
the Japanese Society of Endourology and Robotics. And The ureteral stent was removed at 4 weeks after surgery.
the two surgeons who performed RALP did not perform Follow up was scheduled for evaluation of clinical, urine
LP as surgeons or assistants. examination and the renal US. A diuretic renogram was
also performed at 6 to 12 months postoperatively.
Retroperitoneal laparoscopic pyeloplasty
Our technique for LP has been described in the previ- Statistical analysis
ous study.12 A camera port was made in the middle We used the Student T-test for comparison between two
axillary line at the midpoint between the 12th rib and groups that showed equal variance. On the other hand,
the iliac crest. A balloon dissector was used to create the Mann-Whitney test was used between two groups
retroperitoneal space, a 12–mm trocar was placed. One showing non-normal distribution or non-uniform

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 N. Lukkanawong et al.

Fig. 1. Trocar placement for left robotic-assisted pyeloplasty. A, Assistant port (12 mm); C, Camera port (12
mm); R, Robotic arm port (8 mm).

variance. In addition, in comparison of the ratio between loss (305 and 600 mL), but all of them did not require a
the two groups, a chi-square test was used. For each blood transfusion. Regarding complications, no intra-
test result, a corresponding two-sided P-value of < 0.05 operative complications were observed in both groups.
was considered statistically significant. All analyses While in postoperative period, one patient in the RALP
were performed using SPSS software (IBM, Statistical group was Clavien-Dindo level IIIa. This patient had
Package for the Social Sciences ver 23, Chicago, IL). ureteral stent obstruction by a blood clot, which required
to change stent by cystoscopy under local anesthesia.
RESULTS The median time for drain removal in LP group was
A total of 25 patients were included in this study. 3 days (range 2 to 4), which is significantly more than
Thirteen and 12 patients underwent LP and RALP, 2 days (range 1 to 4) in RALP group (P = 0.029). The
respectively. Patient demographics and characteristics median length of hospital stay after surgery was similar
data are shown in Table 1. There were significantly in both groups were equivalent at 8 days (P = 0.677).
higher BMI in LP group than RALP group (P = 0.012). The success rate, defined as resolution of symptoms and
However, the gender, age, side, clinical presentation, improvement of obstruction on a diuretic renogram,
and history of previous surgery were similar in both were similar at 100% for both groups. No open conver-
groups. The crossing vessels were encountered in 5 sions were required for all patients. The median follow-
(39%) patients in LP group and 4 (33%) patients in up was 24 months.
RALP group and they could be preserved in all cases.
Two (15%) patients in LP group had concomitant stones DISCUSSION
compared with 2 (17%) patients in RALP group. At the present, LP and RALP surgery have become al-
The median operative time for RALP, including ternative procedures with a minimally invasive surgery
docking time, was significantly shorter than LP (296 for the treatment of UPJO. The highly popular proce-
minutes vs. 199 minutes in LP and RALP, respectively) dures displayed treatment effectiveness at a high level
(P = 0.001), while the median robotic docking time comparative to that of open pyeloplasty which once was
was 6 minutes (range 2 to 17) (Table 2). There was no the gold-standard surgery in the past.13 Furthermore,
significant difference in the median EBL between LP these procedures provided the advantages of lower
and RALP (5 mL vs. 0 mL, respectively) (P = 0.168). morbidity, less postoperative pain, and shorter hospital
However, 2 cases in LP group had significant blood stays. Nevertheless, it was found that LP demanded high

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 Laparoscopic and robot-assisted pyeloplasty

Table 1. Baseline demographics and disease characteristics (n = 25)

LP, RALP, P-value
n = 13 n = 12
Age, yrs (range)† 23 (12−62) 29 (11−70) 0.557
Sex: male/female 7/6 8/4 0.688
BMI, kg/m2 (range)† 22.2 (16.6−25.0) 18.4 (12.9−21.9) 0.012
Side: right/left 4/9 4/8 0.891
Presentations 0.961
Pain 9 9
UTI 2 1
Hematuria 1 1
Incidental finding 1 1
Crossing vessels, n (%) 5 (38.5%) 4 (33.3%) 0.79
Concomitant stones, n (%) 2 (15.4%) 2 (16.7%) 0.93
Previous surgery, n (%) 2 (15.4%) 0 (0%) 0.157
†Age and BMI were expressed as "Median". BMI, body mass index; LP, laparoscopic pyeloplasty; RALP, Robot-assisted pyeloplasty;
UTI, urinary tract infection; yrs, years.

Table 2. Perioperative and postoperative outcome

LP, RALP, P-value
n = 13 n = 12
Total operative time, min (range)† 296 (185−498) 199 (173−296) 0.001
Robot docking time, min (range)† 6 (2−17)
EBL, mL (range)† 5 (0−600) 0 (0−50) 0.168
Complications
Intraoperative 0 0
Postoperative: Clavien-Dindo Grade IIIa, n 0 1
Drain duration, days (range)† 3 (2−4) 2 (1−4) 0.029
Hospital stay, days (range)† 8 (5−15) 8 (6−13) 0.677
Conversion to open surgery, n (%) 0 0
Success rate, n (%) 13 (100%) 12 (100%)
†Total operative time, robot docking time, EBL, drain duration, and hospital stay were expressed as "Median". EBL, estimate blood
loss; LP, laparoscopic pyeloplasty; RALP, Robot-assisted pyeloplasty.

intracorporeal suturing skill and longer operative time LP vs. RALP treatments from 8 research studies which
comparative to open surgery.14 showed success rate exceeding 90%, and 5 of which
After the robotic system has been introduced to exhibited success rate at 100% for both LP and RALP. It
operative treatment, various limitations on laparoscopic was found that success rates of RALP were higher than
surgery could be demolished including decreased learn- those of LP (100% vs. 97% and 99% vs. 97%) in 2 stud-
ing curve, reduced fatigue of a surgeon during surgery ies. In contrast, there was only one study reported that
operation and increased effectiveness of operative treat- success rate of LP was greater than that of RALP (100%
ment. With 3 dimensional visualization (3D) including vs. 97%). However, the difference showed no statistical
freedom movement of robotic wrist, stable view, tremor significance.17 Moreover, our study found that success
filtering, and motion scaling, RALP procedure has rates of both LP and RALP were equivalent at 100%
gained higher popularity among surgeons.15, 16 when evaluation was performed from relief of symp-
Braga has conducted a meta-analysis to compare toms and improve obstruction on a diuretic renogram.

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 N. Lukkanawong et al.

Furthermore, there was no open conversion discovered in this group. Fortunately, laparoscopic suturing was
in both groups. Additionally, our study has disclosed achievably conducted to stop bleeding in both cases. For
that median operative time of LP was 296 (185−498) RALP group, there was 1 case discovered with postop-
minutes, whilst that of RALP was 199 (173−296) erative complication from ureteral stent obstruction by
minutes. The results suggested that RALP employed blood clot. The patient was performed cystoscopy with
shorter total operative time comparative to that of LP stent changing under local anesthesia. Subsequently,
with statistical difference. Light et al. has performed there was no further postoperative complication found
a meta-analysis study to compare the operative time later.
of LP and RALP in both children and adults from 14 In our research, we found that drain removal could
research studies.18 The results indicated that there were be performed earlier in RALP group comparative to
4 studies showing comparatively identical operative LP group with statistical significance. Median time for
time in both LP and RALP. Whilst, there were 8 studies drain removal in RALP and LP groups were 3 (2−4)
exhibiting shorter operative time in RALP compared days and 2 (1−4) days, respectively. Since the RALP
to that of LP with statistical significance. In contrast, surgery encouraged a surgeon to certainly qualify anas-
there were 3 studies showing that LP statistically tomosis suturing procedure comparative to that of LP,
significantly display shorter operative time comparative the drain removal in RALP group could be conducted
to RALP. According to the results from meta-analysis earlier. The results from meta-analysis performed by
studies performed by Light et al., it can be concluded Light et al. has found that LOH in RALP was shorter
that RALP employed operative time shorter than LP for than that in LP for 1.2 days.18 In contrast, our research
27 minutes. Interestingly, it was believed that assisted discovered that it was comparatively the same between
robotic surgery involved shorter anastomosis suturing both groups, 8 (5−15) days for LP versus 8 (6−13) days
comparative to that of laparoscopic surgery.18 for RALP. The causes of longer LOH in our research
However, Link et al. has reported that LP displayed was that the patients were regularly allowed to stay
operative time shorter than that of RALP with statisti- in hospital until drain and Foley catheter were off and
cal significance.19 Furthermore, RALP surgery could patients get normal routine activity. Some patients were
expedite anastomosis suturing procedure, though, some worried of the distance between the hospital and their
operative steps, such as colon reflection, consumed residences and demanded to stay longer at the hospital
more time comparative to laparoscopic surgery since to assure their recovery. In comparison with a study of
the robotic arms have been designed to operate with Patel et al., which has reported 1.1 days for LOH, whilst
more effectiveness for precise than gross movements. the recovery time until the patients could continue all
Additionally, the robotic system consumed more time routine independent activities of daily living was 7.7
for robot docking and undocking.20 Moreover, especial days, this recovery time and our LOH were compara-
novice surgery center with low experience in robot- tively similar to each other.23
assisted surgery would consume more time for setting There are several limitations to this study. First,
up procedure. Therefore, the operative time not only the pooled sample size was not powered to compare
depended upon surgeons, but also experience and mas- the results of LP and RALP in patients with UPJO.
terfulness of the entire robotic team.18, 21 Moreover the design of this study was a retrospective
Lucas et al. has reported a study comparing the review. Consequently, a retrospective or prospective,
surgery results by LP and RALP, performed in 274 and multi-center, cohort study taking into consideration the
465 patients, respectively.22 No statistically significant limitations of this study is needed to confirm the results.
difference has been found in intraoperative complica- Secondly, the LP and RALP procedures was performed
tions, postoperative complications and anastomotic leak. by more than one surgeon, each with different levels of
In our study, intraoperative complications were not ob- experience. Therefore, this may have an impact on the
served in both groups. However, it has been found that perioperative and postoperative outcomes of LP and
there was intraoperative significant blood loss among 2 RALP.
patients operated by LP (305 and 600 mL, respectively), In era of minimally invasive surgery, LP and
but blood transfusion was not required. Furthermore, RALP treatments of UPJO have played critical roles and
one case in this group was previous performed balloon emerged widespread with equivalently qualified success
endopyelotomy with no success, therefore, it was dif- rates comparatively the same to that of the standard
ficult during LP surgery as a result of adhesion leading open technique. The robotic surgical systems have been
to renal parenchymal tear. Moreover, bleeding from continuously developed to overcome the limitations of
inadequate renorrhaphy was indicated in another case laparoscopic approach. In our study, we have clearly

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 Laparoscopic and robot-assisted pyeloplasty

indicated that RALP displayed higher advantages than 12 Isoyama T, Iwamoto H, Inoue S, Morizane S, Hinata N, Yao A,
LP in the features of shorter operative time, less blood et al. Hydronephrosis after retroperitoneal laparoscopic dis-
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alternative treatment. 13 Autorino R, Eden C, El-Ghoneimi A, Guazzoni G, Buffi
N, Peters CA, et al. Robot-assisted and laparoscopic repair
Acknowledgments: The authors would like to thank Tottori of ureteropelvic junction obstruction: a systematic review
University Hospital for providing the opportunity to conduct and meta-analysis. Eur Urol. 2014;65:430-52. DOI: 10.1016/
this study. j.eururo.2013.06.053, PMID: 23856037
14 Jarrett TW, Chan D, Charambura TC, Fugita O, Kavoussi
The authors declare no conflict of interest. LR. Laparoscopic pyeloplasty: the first 100 cases. J Urol.
2002;167:1253-6. DOI: 10.1016/S0022-5347(05)65276-7,
PMID: 11832708
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