NEPHROLITHOTOMY WITH AND WITHOUT RETROGRADE PYELOGRAPHY: A RANDOMIZED
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ALI TABIBI, HAMED
AKHAVIZADEGAN, KIA NOURI-MAHDAVI, MOHAMMAD NAJAFI- SEMNANI, MOJGAN KARBAKHSH,
ALI R. NIROOMAND
Urology, Dr Labbafinejad Hospital, Shahid Beheshti University of Medical
Sciences, Tehran, Iran, Section of Urology, Baharloo Hospital (HA) and
Department of Community Medicine (MK), School of Medicine, University
of Tehran, Tehran, Iran
Since the introduction of percutaneous nephrolithotomy (PCNL), many changes
have been added regarding the entrance to pyelocalyceal system such as
insertion of the needle pointed to an opaque stone as a guided landmark.
We aim at comparing the outcomes of managing renal calculi with and without
Materials and Methods: In a randomized clinical
trial, 55 cases with opaque renal calculi candidates for PCNL with stone
in one calyce, in the pelvis or both in one calyce and the pelvis simultaneously
were included in a nine-month study. They were randomized into 2 groups,
noncatheterized (n = 28) and catheterized (n = 27), called intervention
and control groups, respectively.
Results: The 2 groups had similar distributions
regarding gender, age, duration of operation, length of hospital stay,
past history of any surgical procedures on kidney, and stone size. Outcome
(residual stone based on aforementioned management) was evaluated with
plain X-ray on the morning following the operation. Postoperative hemoglobin
decrease was significantly higher in controls than in the intervention
group (p < 0.001) (with no clinical significance). No difference in
outcome, postoperative fever, duration of surgery, duration of hospital
stay and radiation exposure was observed between the 2 groups.
Conclusion: Our findings showed no differences
in major clinical outcomes between the 2 groups (with and without catheter
insertion for retrograde pyelography).
words: urolithiasis; percutaneous nephrolithotomy; pyelography
Int Braz J Urol. 2007; 33: 19-24
the introduction of percutaneous nephrolithotomy(PCNL), many changes have
been added regarding the entrance to pyelocalyceal system such as insertion
of the needle pointed to an opaque stone as a guided landmark (1) (vs.
the classic method of system enhancement with retrograde injection of
air or contrast media) (2). Both methods have been widely used but we
did not find any randomized clinical trial comparing them. In the classic
method, the surgeon must perform an additional procedure to insert a ureteral
catheter. Thus, if the latter is as efficient as the former in the elimination
of stones, it is a good idea to perform PCNL without catheter insertion.
In this study, we aim at comparing the clinical outcomes of renal calculi
management with and without retrograde pyelography.
a randomized clinical trial, 55 cases with opaque renal calculi in one
calyce, renal pelvis or one calyce and renal pelvis simultaneously who
were candidate for PCNL were included in a 9 month study (from September
2003 to June 2004). All patients had intravenous pyelography without any
anatomical abnormality before surgery. They were randomized into 2 groups
without (n = 28) and with ureteral catheter insertion (n = 27) (called
intervention and control groups, respectively). Age, gender, past history
of any surgical procedures on kidneys, side of the involved kidney, postoperative
hemoglobin decline, postoperative fever, duration of PCNL (in minutes),
radiation duration, length of hospital stay and outcome (stone-free, insignificant
residuals, need for extracorporeal shock wave lithotripsy, need for additional
PCNL and need for transureteral lithotripsy were recorded for each patient.
PCNL was performed classically in the controlled group, with the insertion
of the ureteral catheter and the performance of a retrograde pyelography
(with air or contrast media) and the assessment to the proper calyce.
In the intervention group, the pyelocalyceal
system was approached with the insertion of a small needle toward the
opaque stone, without any ureteral catheter insertion. In fact, after
viewing the stone with fluoroscopy, the needle is inserted toward it.
In case it is proved to be successful for the system, entrance (i.e. urine
aspiration) the contrast media (urographin) is injected to find out if
the direction of the needle in the system is appropriate (a blood-less
route like calyceal caps or fornices). If so, dilatation is performed.
Otherwise, a better direction is tried using the enhanced system toward
the stone. On the other hand, if the first trial for the system entrance
was not successful, the second puncture is performed under the guide of
fluoroscopy targeting the stone. Enhancement of the system with intravenous
pyelography is used only if multiple attempts for the system entrance
were not successful. After dilatation, lithotripsy was performed with
lithoclast (ballistic source).
Postoperative outcome was evaluated using
plain X-ray performed on the morning after procedure.
SPSS version 10 was used for statistical
analysis. Kolmogrov-Smirnov test was used to test for normality of quantitative
variables. Student t test and non-parametric (Mann-Whitney U) test were
used for statistical analysis. P ≤ 0.05 was considered as significant.
2 groups had similar distributions regarding gender, age, past history
of any surgical procedures on kidneys except for the side of kidney stone.
Demographic features and other characteristics of the two groups are demonstrated
in Table-1. There was no significant difference between the 2 groups regarding
stone location (calyce, pelvis, or calyce and pelvis simultaneously).
The findings of the major outcomes are presented below.
Mean duration of surgery was 73.2 ± 26.37
minutes in catheterized group and 62.86 ± 17.66 in the noncatheterized
group (p > 0.05).
The average duration of radiation exposure in
the noncatheterized group was 2.58 ± 1.47 and 2.66 ± 1.2
minutes in the other (p > 0.05).
Hospital stay in the catheterized group was 2.7
± 1.08 and 2.93 ± 2.16 days in the noncatheterized group
(p > 0.05).
Prevalence of post-PCNL fever in catheterized
was 23.2% versus 18.5% in the noncatheterized group (p > 0.05).
Postoperative hemoglobin decrease was significantly
higher in PCNL in the catheterized (2.29 ± 1.25) when compared
to the noncatheterized group (1.03±0.9) (p < 0.001).
No difference in outcome was observed between
the 2 groups (p = 0.136). Around 93 percent of the patients in the catheterized
group (n = 26), were stone free on the day after operation, whereas in
the noncatheterized group, only 78.6 percent of the patients (n = 22)
were stone free on the day after operation. One patient in the noncatheterized
group and 5 patients in the catheterized group needed ESWL. Additional
PCNL was required in one patient in the noncatheterized group. Even after
recoding outcome (stone free vs. else) no difference was detected between
the 2 groups (p = 0.2).
this date, experience with PCNL without catheter has been limited to catheter
insertion preoperatively and removing immediately afterwards (3). In this
research, the catheter was not inserted from the beginning in the intervention
group and the outcomes were compared with the classic PCNL.
In the classical approach to pyelocalyceal system,
the system is opacified with retrograde pyelography with air or contrast
media (2). Using a catheter may facilitate access to enhanced system (due
to some pyelocalyceal distension) and can provide us with better directions
in PCNL (4); though we did not find such benefit. In PCNL with catheter,
a constant access to pelvis is provided and in case of any complications,
successful management is more achievable.
Access to enhanced system may theoretically reduce
blood loss (5,6) (due to entrance via a hypovascular plane) and decrease
the incidence of residual stones (due to most proper direction), but we
did not find such benefits. It seems that targeting the stone from a point
medial to the posterior axillary line (maximum 4-finger width lateral
to the para-vertebral muscle), saves this hypovascular plane. Entrance
to the system with antegrade pyelography has been widely used (1) and
fluoroscopic evaluation of the collecting system during antegrade pyelography
is probably the best technique to use (7) but in normal systems with simple
stones, like what we had in our cases, performing retrograde pyelography
does not sound necessary. In addition, the enhanced system may need less
radiation exposure or reduce the total time of surgery; though no difference
was observed in this regard.
Using balloon ureteral catheter insertion in PCNL
has some benefits such as inhibiting migration of stone particles to the
ureter (4). Due to financial implications, it is not a routine to use
balloon ureteral catheter for PCNL in our center and simple ureteral catheter
is used instead. Nevertheless, migrated ureteral stones are infrequently
seen in our cases. In our study, the rate of migrated ureteral stones
needing ureteroscopy was not different in the 2 studied groups. This finding
is also justifiable, as simple ureteral catheter used in the control group
does not provide any protection in this regard as discussed above.
The use of ureteral catheter may introduce bacteria
from the lower urinary tract to the upper system and its insertion requires
another procedure (cystoscopy) to the patients. In addition to this potential
complication, air embolism may rarely occur during retrograde pyelography
(8). In this study, no increase in the rate of post-PCNL fever was observed
in PCNL either with a catheter or without it. Moreover, PCNL without ureteral
catheter can reduce postoperative discomfort due to less pain and less
urine leakage, although this was not assessed in our study.
differences in major clinical outcomes were observed between PCNL either
with or without catheter. Considering other benefits of PCNL without stent
insertion (e.g. no need to cystoscopy and lower amount of urine leakage
as only one catheter is inserted in the urethra), it is a safe alternative
procedure. Selection of patients for PCNL without catheter may be limited
to those with opaque stones in pelvis or/and in one calyce. It is also
a safe procedure for accessing to pyelocalyceal system in patients with
difficulty for cystoscopy (due to positioning or urethral stricture).
research was funded by Urology Nephrology Research Center, Shahid Beheshti
University of Medical Sciences, Tehran, Iran. The authors wish to thank
Dr. Fereydoon Khayyamfar and Dr. Esmaeel Moosapour for their contribution
to this study.
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October 4, 2006
Dr. Hamed Akhavizadegan
Shahid Dr. Labbafinegad Hospital
9th Boostan Street, Pasdaran Avenue
is long known that the urinary system may be enhanced by injecting contrast
media through a ureteral catheter or directly by a lumbar needle puncture.
Such enhancement may ease the establishment of the nephrostomy tract.
The choice of the calyx to be punctured, preferentially through a posterior
calyceal papilla, is based on the stone size and location, and also on
the morphology of urinary tract. Generally the calyx chosen for puncture
must offer the best nephroscope access to calyces with stones and to renal
a selected group of patients, the authors clearly demonstrated that percutaneous
surgery might be performed with the same efficacy using or not a ureteral
catheter. Such conclusion does not necessarily imply in a change of conduct,
but reinforces that the ureteral catheter is not an indispensable tool
for percutaneous surgery, especially in patients where it is impossible
to insert it.
insertion of a ureteral catheter is a 10 minutes procedure that allows
the injection of contrast media, saline or air, and may be useful to prevent
migration of stone fragments to the ureter (not observed in this paper).
It may also allow the introduction of a guide wire during the percutaneous
surgery for a double J catheter insertion whenever it is needed.
great merit of this paper is showing that percutaneous surgery may be
successfully accomplished without the insertion of a catheter. Nevertheless,
the suggestion of abolishing such procedure is unwise, as it has the aforementioned
advantages. The surgeon will never regret inserting the ureteral catheter,
but may regret not doing so.
Associate Professor of Urology
Sao Paulo University Medical School
Sao Paulo, SP, Brazil
authors of this manuscript have challenged the long-held dogma, that retrograde
ureteral catheter insertion and contrast administration is necessary for
safe and successful percutaneous renal access prior to percutaneous nephrolithotomy
(PCNL). Many of us who perform PCNL have likely been faced with the situation
where retrograde opacification of the collecting system was impossible
due to previous urinary diversion or ureteral obstruction. In those instances,
the use of intravenous contrast or antegrade pyelography to allow collecting
system opacification, or the use of ultrasound to guide renal access are
In this paper the authors conducted a small randomized
trial to compare the outcomes between a group of patients undergoing PCNL
in the conventional way utilizing retrograde ureteral catheter insertion
versus a cohort in which percutaneous access was achieved without the
use of a retrograde catheter. Exactly how patients were randomized is
not detailed in the paper; however it is confirmed that the 2 groups were
similar preoperatively with respect to age, sex, previous kidney surgery
and stone size. Whether stone location was similar between groups is not
mentioned. This would seem to be an important piece of information because
if I understand their technique correctly, needle insertion is performed
directly onto the stone when retrograde contrast was not used, regardless
of whether the stone was calyceal or renal pelvic in location.
risks with blind insertion into a stone-bearing calyx are likely less
than the potential problems with placement of the needle directly into
the renal pelvis. Although direct needle access into the renal pelvis
is unlikely to cause much harm in most patients, potential vascular concerns
must be acknowledged. Once urine is obtained, antegrade contrast is injected
to delineate the collecting system. With direct renal pelvic needle placement
and if contrast extravasation occurs, one must wonder if this may impede
fluoroscopic visualization, and make proper tract access more difficult.
The authors indicate that should access not be achievable without the
use of retrograde contrast they will resort to intravenous contrast. How
often this was required in their series is not documented.
In the presentation of the results, it is mentioned
that the duration of surgery, radiation time and hospital stay was not
different statistically between the 2 groups. Blood loss was higher in
the catheterized group, with no explanation provided to account for this.
The authors claim the stone free rates were not different statistically
either, however a review of the raw data would suggest otherwise: They
report 26 patients in the catheterized group were stone free. With a denominator
of 27 this would equal a 96.3% stone free rate, not the 93% rate mentioned
in the paper. In the non-catheterized group they report 22/28 (78.6%)
stone free rate. As such I would argue the differences are in fact more
significant than they have claimed.
the discussion section, the authors list the potential advantages associated
with the avoidance of ureteral catheter insertion. Although it is always
healthy to be critical of traditional doctrine, the arguments supporting
a change of current practice must be compelling. The authors claim that
a separate procedure is required to perform retrograde catheter insertion.
At our centre as at many others, flexible cystoscopy and catheter insertion
with the patient prone is performed immediately prior to and as a part
of the PCNL procedure. The risk of air embolus with retrograde air injection
is an extremely rare event if the volume of air used is small. Finally,
postoperative patient discomfort from the ureteral catheter is highlighted,
but in the majority of instances the ureteral catheter can be removed
at the conclusion of the PCNL procedure before the patient is even awakened
from anesthesia. In my mind the arguments presented do not seem compelling
enough to warrant a modification in technique in my own practice.
said that though, the authors have given us food for thought and should
be commended for their efforts to further refine PCNL. As I read this
paper I recalled the words of one of my earliest endourology mentors,
who used to say, “percutaneous nephrolithotomy is a procedure of
millimeters”. To paraphrase, he was trying to say that surgical
precision is important in to the safety and success of this operation.
As such whatever technical modifications we consider must preserve that
Dr. Hassan A. Razvi
Chair, Division of Urology
University of Western Ontario
London, Ontario, Canada
REPLY BY AUTHORS
read the editorial comments. I agree with the items that are suggested
in comments. The less invasive method must be the safer method. This way
is only an alternative to classic method in special cases.
think that only entrance of needle to vessels does not cause any problem.
Moving the needle through that direction (from behind near tip of 12th
rib to stone) very rarely may encounter the renal pelvis directly.
this study no patient need IV administration of contrast media.