Comparative Study for the Percutaneous Technique Vs. Laparoendoscopic Single-Site Surgery for the Treatment of Pyelic Lithiasis
Alessandro Vengjer<1* and Marcos Tobias Machado2
1 Department of Urology, School of Medicine of ABC, Brazil
1 Head of the Uro-Oncology Sector of FMABC and researcher at FMABC, Brazil
Submission: May 07, 2018; Published: June 08, 2018
*Corresponding author: Alessandro Vengjer, Department of Urology, School of Medicine of ABC, Brazil, Tel:5513981329951; Email: email@example.com
How to cite this article:Alessandro V, Marcos T M. Comparative Study for the Percutaneous Technique Vs. Laparoendoscopic Single-Site Surgery for the Treatment of Pyelic Lithiasis. JOJ uro & nephron. 2018; 5(4): 555668. DOI: 10.19080/JOJUN.2018.05.555668
Introduction: The standard treatment for pelvic lithiasis with calculi larger than 2cm is Percutaneous Nephrolithotripsy (PCNL); however, in selected cases laparoscopic treatment may have advantages. The single portal technique (LESS) is an option putatively associated to an additional reduction of morbidity, when compared to conventional laparoscopy.
Objective: To compare the techniques of single-portal pelvicolithotomy vs. percutaneous nephrolithotripsy for the treatment of pyelic lithiasis.
Methods: We compared the prospective results of 10 sequential cases submitted to LESS pelvicolithotomy with 40 cases of (PCNL) for the same indication and calculus size.
Results: The mean surgical time was significantly higher at 162min for LESS vs. 115min for PCNL (p=0.02). The estimated mean bleeding was significantly lower (p< 0.01) with LESS (hemoglobin variation range: 0.3 and 0.9g/dL) vs PCNL (0.3 to 8.7g/dL). No transfusions were required for LESS cases, while 2 PCNL cases were transfused (p=0.31). No other severe postoperative complications were identified in either group. Similar mean hospital time were observed. Residual calculi occurred in 2 cases of PCNL but not in LESS (p=0.16). No second procedure was required after LESS, whereas one was required after PCNL.
Conclusion: LESS surgery is a therapeutic option and may be an alternative to PCNL in selected cases, especially if it is validated by multicentric studies with larger samples.
Renal lithiasis is one of the most common benign urologic diseases . Due to the development endourological techniques, surgery for renal and ureteral lithiasis has all but disappeared. Such surgical procedures are well tested and developed techniques, over many years. However, they are invasive and result in very poor aesthetic and functional results; the required lumbotomy often result in chronic pain, incisional hernia, muscular flaccidity and long periods away from work. Endourological surgery has made important advances in recent years, but even so, in some situations, they do not offer complete or totally safe solutions. Among these, the Percutaneous Nephrolithotripsy (PCNL) which (according to the 2015 EAU Guideline) is the preferred technique for large pyelic calculi
(>2cm);  however, it may not be so adequate for cases of anatomical abnormalities and very large volume calculi .
Percutaneous Nephrolithotripsy (PCNL) was first reported by Fernstrom & Johansson  and subsequently, it was established as a technique routinely used to treat patients with large or complex calculi .
Even when performed by experienced urologists, the PCNL procedure may lead to severe complications, which can occur in 7% of patients as well less serious complications in 25% of cases . Bleeding is the most important complication, with reported transfusion rates of ranging from 1% to 10% of patients. Bleeding from an arteriovenous fistula or pseudoaneurysm
requiring angiography and embolization occurs in less than
1% of patients . Postoperative infectious complications are
found in nearly 25% of patients due to injury of adjacent organs
(intestine, spleen), failure to access the target and perforation
of the renal pelvis and/or the ureter. The need for conversion
to open surgery is rare. The mortality rate of PCNL is between
0.03% and 0.8% . Colon injury is an uncommon complication
The gap left open by difficulties or risks of open technique
and endoscopic surgeries has been filled by laparoscopy, a
technique that aims to replace classic pelvic lithotomy through
lombotomy in cases where open surgery is indicated. In Europe
and the United States, open surgeries for urinary calculi are only
indicated for cases of large and hard stones, following the failure
of extracorporeal lithotripsy, percutaneous nephrolithotripsy or
ureterolithotripsy, or even in cases of anatomical abnormalities
Pelvic calculi can be treated by PCNL or laparoscopy, the
latter allowing for the complete calculus removal without
fragmentation, preventing damage of the renal parenchyma; it
also allows the treatment of other associated diseases such as
Pelviureteric junction (PUJ) stenosis .
The use of laparoscopy for the treatment of upper urinary
tract lithiasis was first reported in 1992 by Raboy et al. 
However, it was Goel & Hernak  who compared the open
and laparoscopic techniques of ureterolithotomy, concluding
that they were similar in result. In terms of pain, bleeding,
hospitalization time and return to normal activities, laparoscopy
was reported as the better procedure.
The Single Port Pyelolithotomy (LESS) technique for the
treatment of proximal lithiasis was first described in 2008 by
Rane et al.  Other studies showed the possibility of using
a home-made Single Port device, using a glove and an Alexis
retractor [14,15] as an alternative. The first description of a
series of LESS was performed by our group and presented at the
Brazilian Congress of Urology of 2015 .
Because no comparisons between PCNL and LESS have
been reported, the objective of this study was to compare our
initial experience in LESS with PCNL data for the treatment of
large (>2cm) calculi. This study aims to compare percutaneous
surgery and single-portal pyelolithotomy in terms of
The present study consisted of 50 patients, 10 of whom
underwent surgical treatment using the Single Port Laparoscopic
Pyelolithomy (LESS) technique, consisting of our initial
experience with this method and paired with 40 patients from
our institution submitted to Percutaneous Nephrolithotripsy
(PCNL), to compare possible complications relating to these
techniques. We specifically selected patients which presented
exclusively pyelic calculi. Different single portal approaches were
used in different cases according to the best strategy to establish
access in each case. Strategy also defined whether conventional
laparoscopic or minilaparoscopic tweezers were used
Cases were matched by similarity in size of the calculi, 1 case
of LESS matching 4 cases of PCNL. Body mass index was paired
as closely as possible, as shown in Figure 1. Residual calculi
were defined as larger than 4mm and/or symptomatic and/or
generators of dilatation.
In the study for LESS, individuals with pyelic lithiasis greater
than 2 centimeters who had an indication of PCNL as a function
of size and/or density of the calculus and those who failed
treatment with extracorporeal shock wave lithotripsy (SWL)
were randomly selected from those awaiting the completion
of PCNL at the Hospital Mario Covas, linked to ABC Medical
School, in São Paulo, Brazil. The study included male and female
patients at least 18 years old, regardless of race, creed, education
or marital status. Only patients who understood and accepted
the study conditions and signed the informed consent form were
included. The study was approved by the institutional ethics
Patients were submitted to general anesthesia, a double
J catheter was implanted after ureteroscopy, followed by
placement of a bladder catheter; the patient was then
repositioned to a lateral decubitus and the bladder catheter was
placed contralaterally to the surgical side as shown in (Figure
2).The single portal was installed through a cutaneous incision
and posterior divulsion of the muscular planes with access to
the retroperitoneum. In eight cases, the Alexis retractor was
coated with a surgical glove (Figure 3). Laparoscopic tweezers
were Mini Storz (Figure 4) and, in some cases, conventional
laparoscopic tweezers. In two cases, we used the Single Storz
Portal (Figure 5) and minilaparoscopy tweezers (5mm optics
and 3mm tweezers). In one case, we inserted the Single Taimin
Portal; however, because of gas leakage, it was replaced by the
Alexis Retractor with a surgical glove with conventional clamps;
in two cases, we used a 3mm auxiliary portal. After access and
installation of the portal, the structures of the retroperitoneal
compartment were identified, and a pelvic incision was made to
access the calculus, which was removed from the cavity, followed
by pelvic suture. All 10 LESS procedures were performed by a
single surgeon with extensive experience in laparoscopy.
Patients were submitted to general anesthesia, positioned
for lithotomy with insertion of a ureteral catheter, with posterior
modification of the decubitus to ventral. Pyelography was
performed by the ureteral catheter and 18G needle puncture,
followed by dilatation with Amplatz up to 30 Fr, leading to
renal access by rigid nephroscopy (no flexible nephroscope
was used) with identification of the calculus. Fragmentation
was performed with ultrasound lithotripsy and removal of the
fragments with trident forceps, followed by double J catheter
implantation and nephrostomy. All 40 PCNL procedures were
performed by a single experienced surgeon in the Urolithiasis
Sector of the institution.
The analysis was made using the data obtained in the 10
LESS procedures and in the 40 PCNL procedures. We considered
size of the calculi, age, body mass index, hemoglobin and
hematocrit, pre-and post-operative time, length of hospital stay,
complications according to the Clavien-Dindo scale , number
of blood transfusions, surgical time, need for second procedure
and residual calculi. Table 1 shows the demographic data of the
Calculus size ranged from 2.5 to 3.7cm (mean: 3.06cm) for
LESS vs. 2 to 5cm (mean: 2.88) for PCNL. Regarding age, patients
age ranged between 30 and 71 years (mean: 48.5 years) in for
LESS vs. 19 and 74 years (mean: 40.8 years) for PCNL; BMI
ranged 23 to 41.5kg/m2 (mean: 28.91kg/m2) in LESS vs. 20
and 33kg/m2 (mean: 24.7kg/m2) for PCNL as shown in Table
2. Significantly smaller reductions (p< 0.01) occurred pre to
postoperative Hb in LESS (from 0.3 to 0.9g/dL - mean: 0.6g/dL)
vs. PCNL (0.3g to 8.7g/dL - mean: 3.29g/dL). Length of stay: 2
to 4 days (mean: 2.7 days) for LESS vs. 2 to 7 days (mean: 2.65
days) for PCNL. With respect to complications, all LESS cases
presented grade I of Clavien-Dindo . For PCNL, three cases
(7.5%) presented grade II of this scale, due to the need of blood
transfusions. There were no cases of transfusion in LESS vs. two
cases in PCNL. The duration of the procedure was significantly
higher (p=0.02) for LESS (162 minutes - range: 90 to 220min)
vs. PCNL (115 minutes - range: 40 to 240min), as shown in Table
3. Complementary procedures were not necessary for LESS (no
residual calculi), vs. two cases (5%) of residual calculi in the
PCNL patients. Functional and cosmetic results, shown in Figure
6 were quite satisfactory for both procedures.
Statistical analysis showed statistically significant differences
for Hb (better for LESS), surgical time (shorter for PCNL); no
significant differences were found for BMI, size of the calculi, age,
residual calculi, time of hospitalization or transfusions (Table 4),
which may be visually inspected in Figure 7 & 8.
The 2015 EAU Guideline2 indicates that kidney stones
larger than 2 centimeters may be treated either with SWL
or PCNL (degree of recommendation B); however, larger
calculi have a degree of recommendation A for PCNL. In this
guideline, laparoscopy may be an alternative for cases of PCNL
failure (Figure 9). Thus, laparoscopy has been tried [18,19]
and compared to PCNL [20,21], which is considered the gold
Because there are no articles evaluating Single Port for
Pyelolithotomy vs. other techniques, we used LP data with
multiple portals for comparison in this series.
In this study we examined and compared two general
aspects: efficacy and perioperative morbidity. In these two
aspects, factors such as age, sex, BMI and calculus side did not
exhibit significant differences .
Calculus-free rates: we obtained 100% and 95% rates for
LESS and PCNL, respectively. Equivalent results were found
by Tefleki et al.  with 100% free stone for RLP and 88.4%
for PCNL. The efficacy of the laparoscopic route is largely a
consequence of the fact that calculus removal is performed
without its fragmentation, thus preventing residual fragments to
be left behind , as shown in Table 5.
Surgical time: most authors who have studied this factor
agree that PCNL presents a shorter operative time [22,23], which
was also observed in our series. This has also been described by
Wang et al.  in his meta-analysis. In contrast, Li et al. 
recorded shorter procedure duration with RLP, as also shown in
Hospitalization time: Many authors report a longer PCNL
time [18,22,24], including the Wang et al.  metanalysis with
7 trials totaling 176 and 197 multiport LP and PCNL patients,
respectively. Nambirajan et al.  included multiple renal
calculi and situations in which there was concomitant PUJ
stenosis, with observed hospitalization time between 5 and
35 days. Goel & Hemak  reported lengths of hospital stay
of 3.8 days for RLP versus 3 days for PCNL. However, Li et al.
 in a comparative randomized study, found no differences
between hospitalization time of PCNL vs. Laparoscopy, as we
also observed in our series (2.7 for LESS x 2.65 for PCNL); this is
also shown in Table 5.
Unfavorable anatomical situations: Some reports [22,26]
point out the possibility of using Laparoscopy in cases of ectopic
kidneys or other anomalous formations, with better results vs.
PCNL. In 1997 Harmon et al.  reported the first case in which
a 2.5cm pyelic calculus was completely removed from an ectopic
kidney through a laparoscopic procedure. Later, Ramakumar et
al.  described another case of ectopic kidney pyelolithotomy.
Regarding the efficacy for the removal of a single stone, we
believe our study shows that Laparoscopy by single or multiple
portals presented similar rates of stone-free outcomes, superior
to what was obtained through PCNL, with only slightly higher
lPCNL has its well-established complication rates: the 2015
EAU Guideline reported 7% transfusion rates, 0.5% sepsis, 0.4%
need for embolization and 0.5% rate of mortality . Such risks
are substantially minimized in the comparisons between PCNL
and Laparoscopy, because the latter does not perforate the renal
Transfusion: recently, a multicenter study (CROES) with
5803 patients evaluated complications of PCNL showing a
transfusion rate of 5.7% and fever in 10.5% of cases .
Regarding hemoglobin loss, Tefekli et al.  noticed pre
and postoperative variation of 0.9 ± 0.6g/dL and 1.7 ± 1.1g/
dL, respectively, for RLP and PCNL. Chander et al18 reported
an average blood loss of 27 mL in his RLP series; Wang et al.
 reported a smaller drop in hemoglobin levels in LP, while
Ramakumar et al.  described a blood loss of less than 145mL.
Goel & Hemak  reports bleeding of 147.9mL for RLP versus
173.1mL for PCNL. Aminsharifi et al.  observed no difference
in hemoglobin fall. We found a significantly lesser hemoglobin
decrease for LESS, which is consistent with other reports [20,21]
as shown in Table 6.
Others complications: fever was found less frequently
in LP (3.4% in RLP versus 13.5% in PCNL) , and this was
also demonstrated by Wang et al. . In our series of LESS,
postoperative fever never occurred.
Urinoma, conversion or transfusion were reported by Lee et
al.  in only 1 case out of 77 studied. In our cases, none of
these occurred. Goel et al.  reported the need for conversion
in two cases, due to the peri-pyelic adhesion of a solitary (>3cm)
stone. We emphasize that such adherence was found in all
of our cases, although it did not prevent the procedure to be
successfully completed. We did not objectively evaluate factors
with renal pelvis characteristics (extra or intra renal).
Table 7 presents data from several studies [20,22,24,25,29,30],
which we compared to our series. Regarding postoperative
morbidity/complications, we observed that the Single Port or
Multiport Pyelolithotomy presented less complications with
respect to hemoglobin variation, urinoma and postoperative
fever. It should be pointed out that reports indicate that there
may be technical difficulties due to peri-pyelo inflammatory
adhesions, with a variable conversion rate of 0 to 12% [17,20].
Our study has limitations:
a. We compared our LESS data to a retroactive series of
b. Our sample sized (10 cases) is small;
c. We did not evaluate the retrospective cases series
(PCNL) nor our limited experimental sample (LESS) using
the AST (American Society Anesthesiology) standards for
d. We did not evaluate the impact of using different single
portals nor the different types of renal pelvis presentation.
This comparative series of PCNL and LESS cases is an initial
experience and we believe it will stimulate studies with larger,
controlled and randomized series such as those described for
multiple portals LP which is a more established and tested
procedure to turn LESS into a more thoroughly studied procedure
contributing to its validation as an alternative technique.
Based on the evidence presented here, it may be concluded
that LESS can be seen as an alternative technique to PCNL in
special situations, because it presents
a. Good efficacy (high free rate of calculi, combined with a
slightly longer time of surgery) and
b. Low perioperative morbidity, bleeding rate, low rate
of complications, and surgical conversion. However, these
data should ideally be confirmed by controlled, multicenter
studies performed with larger numbers of included patients.