Title page
Which access is suitable for a solitary upper pole renal
stone?; A possible novel criterion
Running title: solitary upper pole renal stone & access route
Seyed Mohamad Kazem Aghamir MD.1
Seyed Saeed Modaresi MD.1
Mehdi Aloosh MD.1, 2
Hasan Farahmand1 MD. 1
S.Hamed Hosseini,MD, MPH, PhD student 2, 3
Alipasha Meysamie MD.4
mkaghamir@yahoo.com
modaresis@razi.tums.ac.ir
md_aloosh@hotmail.com
hasan.farahmand@hotmail.com
hmdhosseini@gmail.com
meysamie@tums.ac.ir
1. Department of Urology, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran
2. Research Development Center, Sina Hospital, Tehran University of Medical Sciences,
Tehran, Iran
3. Knowledge Utilization Research center (KURC), Tehran University of Medical Sciences,
Tehran, Iran
4. Department of Community Medicine, Tehran University of Medical Sciences, Tehran, Iran
Corresponding author:
Seyed Saeed Modaresi MD
Department of Urology, Sina Hospital,
Emam Khomeini st.
Tehran – Iran
Tel/ Fax: 98 (21) 66716546
modaresis@razi.tums.ac.ir
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Abstract
Objective: To discover a new criterion for choosing subcostal or supracostal upper pole
renal access before performing PCNL in upper pole renal stone cases.
Patients and methods: Between April 2006 and July 2009 we performed 35 subcostal
upper poles PCNL in solitary upper pole stone cases. The inclusion criteria were stone
size > 1.5 cm or stone size < 1.5 cm and resistant to extracorporeal shockwave
lithotripsy. The exclusion criteria were renal anomalies, uretero-pelvic junction
obstruction, multiple stone (associated pelvic or a lower pole stone) and any
contraindication for surgery. We determined access length as the new criterion (the
distance between the point of needle entrance and lower border of stone on the skin)
and access success, in all patients. Then we analyzed the relationship between these
two main variables and used roc curve to find a reliable cut point of access length.
Results: The mean of access length was 9.72 cm (range: 6-14) and access was
successful in 29 (82.8%) patients. Between measured variables, access length was the
only variable that related to access success (P value = 0.04). We found two reliable cut
points (8 cm and 12 cm) for predicting access success. If access length was < 8 cm or
8-12 cm or > 12 cm, the access success would be 100%, 83% and 50%, respectively.
Conclusion: Access length can be used as a criterion for choosing subcostal upper
pole renal PCNL and predicting its success, in the case of solitary upper pole renal
stones.
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Introduction
Percutaneous nephrolithotomy (PCNL) is the best way for managing complex, large or
SWL resistant urinary calculi. The accessibility and visibility of the stone by
nephroscope is a critical issue in this method that means access success. Access
through a suitable calyx is essential in a successful PCNL. Stone location and stone
burden is the primary consideration in selecting the optimal access (1). Between renal
stones, solitary upper pole renal stone needs special considerations. It is a candidate
for PCNL and there are several different ways for getting access to the stone. But, what
is the best access route?
It is reasonable that the entrance to the calyx with stone (upper pole calyx) is the
optimal event. Upper pole renal access can be performed through an infracostal,
intercostal, or supracostal puncture. The subcostal access is the preferable access, as it
has been carried fewer complications (1, 2). using a supracostal access is sometimes
necessary. While, it is mentioned that complications of supracostal puncture are slight
and acceptable, we should try to have the least complication and morbidity (1). If we
preoperatively knew that subcostal upper pole access would be successful, we is better
use this approach; otherwise, we would use the supracostal upper pole access. But,
how can we preoperatively guess which upper pole access would be successful?
Subcostal upper pole access or supracostal upper pole access?
We think that subcostal access length is a predicting factor for successful access, so,
we have evaluated this factor in our study. In brief, our goal was to discover a criterion
for choosing subcostal upper pole access, before performing PCNL and avoid
unnecessary supracostal accesses in the case of solitary upper pole renal stone.
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Patients and methods
After receiving the approval from Tehran University of Medical Sciences’ ethical
committee, informed consent obtained from 35 eligible patients, who had a solitary
upper pole renal stone. The inclusion criteria were stone size > 1.5 cm or stone size <
1.5 cm and resistant to extracorporeal shockwave lithotripsy. The exclusion criteria were
renal anomalies, uretero-pelvic junction obstruction, multiple stone (associated pelvic or
a lower pole stone) and any contraindication for surgery. Between April 2006 and July
2009, all of the patients underwent a PCNL for solitary upper pole renal stone via
subcostal upper pole access.
All patients underwent PCNL under general anesthesia in prone position by one expert
endourologist. Before the surgery, we placed 5 fr ureteral catheter. This catheter was
used for injecting contrast material to pacify the collecting system. Before starting the
puncture under fluoroscopic guidance, we determined two points on the skin. The first
point was in the lower border of the stone and the second was a suitable point for
needle entrance, on the skin. This point was subcostal and appropriately far away from
the midline. We calculated and recorded this distance in centimeter and called it access
length. (Figure 1)
Then, we began the surgery by advancing the needle toward the upper calyx using the
triangulation technique. Once the calyx was entered, a 0.038 inch floppy tip j shaped
guide wire was passed. The nephrostomy tracts were dilated and a 30 fr amplatz sheath
was then inserted. After that, a standard 26 fr nephroscope was used. If we visualized
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the stone by nephroscope, we recorded it as successful access; otherwise, it was
considered as an unsuccessful access. In the case of unsuccessful access, we used
supracostal access.
We recorded and analyzed the data of our patients like age, sex, body mass index,
hemoglobin drop, before and one day after the surgery. In addition, hospital stay, stone
size, duration of surgery, access length and access success were noted. Our two main
variables were access length and access success. We used roc curve to find the best
points of access length that would be practical for predicting successful access. These
points were put on 8 cm and 12 cm. Based on these points, we divided our patients into
3 groups. Access length in group I was below 8 cm, in group II, was between 8-12 cm
and in group III it was above 12 cm.
We used SPSS software to calculate the general success rate of subcostal upper pole
access and if there is a significant relationship between access length and access
success. P value was considered to indicate statistical significance if it was <0.05.
Furthermore, we evaluated access success in all three groups, separately. For
determining odd ratio, we used logistic regression multivariable analysis with 95%
significance.
Results
A total of thirty five patients (35 renal units) who underwent a subcostal upper pole
access PCNL for solitary upper pole renal stone were prospectively evaluated. They
were composed of 23 (65.7%) males and 12 (34.3%) females. The characteristics of
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patients have been shown in table 1. The mean of access length was 9.72 cm (range:
6-14).
All patients underwent subcostal upper pole access at first and only 6 (17.2%) patients
underwent supracostal access, because of unsuccessful subcostal access. Overall, the
access was successful in 29 (82.8%). We evaluated the correlation between
preoperative variables and access success. The odd ratio and P values have been
shown in table 2. The only variable that is related to successful access is access length
(P value = 0.04). It means that the only predicting factor for a successful access is
access length and if access length increases 1 cm, the probability of access success
would be half (OR = 0.522).
We tried to find the best points of access length that would be practical for predicting
successful access. With the use of roc curve, we found that these points are 8 cm and
12 cm. In table 3, the sensitivity and specificity of unsuccessful access is shown in
different access lengths. For example, in the access length of 7.75 cm, the probability of
diagnosis of unsuccessful access before surgery would be 100% (sensitivity = 100%).
Using these points, our patients were divided into three groups. In group 1 the access
length was below 8 cm, in group II between 8-12 cm and in group III above 12 cm.
There were not any statistical differences in age, stone size, BMI, duration of surgery,
Hemoglobin drop and hospital stay among these three groups, but access length and
access success were significantly different. Access success in group I, II and III was
100%, 83% and 50%, respectively (See table 4). This clearly demonstrates that when
access length increases, access success decreases and if the access length is above
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12 cm, the access success will significantly decrease. It means that if the access length
is below 12 cm, we can choose subcostal upper pole approach and if it is above 12 cm,
it would be better to avoid this approach and choose supracostal approach.
Discussion
Since the introduction of percutaneous nephrolithotomy in 1976, it has been established
as the treatment of choice for many renal stones (1, 3), even in the pediatric population
(4). There are many considerations and questions about this surgery like anesthesia,
opacification of the collecting system with air or the contrast material, patient
positioning, selection of puncture site, post operative options (tubeless or non tubeless)
and suitable access (subcostal or supracostal). For access selection, there are many
factors and the most important factors are the stone size and location. In general, stone
location and burden should be the primary considerations in selecting the optimal
access for stone removal (1).
Overall, we should select the simplest way for reaching the pyelocaliceal system and
stone that carries the least complications and morbidity. The ideal site for percutaneous
puncture is the one that provides the shortest tract to calyx from below the 12 th rib. The
lower pole access is preferable because of fewer complications, but an upper pole
access is sometimes necessary (1). For example, in the cases with solitary upper pole
renal stone, reaching the stone via lower pole access is very difficult and sometimes
impossible. As a result, in these situations, we should select the upper pole access and
we can use the subcostal or supracostal puncture for reaching the upper pole. In
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previous reports, it is suggested that supracostal puncture of the upper calyx is more
direct to the long axis of the kidney and giving a smoother passage of the rigid
instruments toward the lower pole, so, supracostal access is preferable for upper pole
renal stones (5-7). Following this presumption, many studies have been performed to
show the safety of supracostal access (8, 9). In one study by Gupta et al, it is supposed
that the supracostal approach is mandatory for superior calyceal stones and these
stones are particularly difficult to approach through the inferior calyx, because of the
angulation of the tract (10).
On the contrary, we believe that they may ignore that we can approach superior
calyceal stones directly through the superior calyx from subcostal access and
supracostal access is not necessary in all solitary upper pole stones. Furthermore, there
are studies that show during percutaneous renal surgery, subcostal access is preferred
because it carries no risk of injury to either the lungs or pleura (2, 11). Supracostal
access carries a slight, real and considerable increasing in complications like intercostal
vessels and nerve, pulmonary, hepatic and splenic injury (12). Pulmonary complications
are the most significant complications and since a few years ago, extensive literature
has been published to evaluate this complication. The reported rate of pneumohydrothorax is varying between 8.7 to 18% (7, 13-15). It is reported that since the
diaphragm is attached to the inferior border of the 12th rib, all punctures passing above
the 12th rib will pierce the diaphragm. However, entry through the pleural space that
causes hydrothorax and requires the insertion of chest tube occurred in 5% of patients
(10).
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Intrathoracic injuries are the most prominent complications of supracostal access and it
is the most important reason for the concern of urologists when performing supracostal
access. We know that many studies demonstrated the real risk of intrathoracic
complications and tried to confirm that these complications are slight and acceptable.
However, performing supracostal upper pole access is a very stressful procedure in
daily practice and they are associated with significantly higher intrathoracic complication
rates compared to subcostal access tracts, this approach must be used with caution
when no other alternatives are available (16) and if there is one, it is preferable.
Renal displacement technique involves placing an amplatz sheath through central or
lower pole calyx for caudal mobilization of the kidney and a second Y- traction to the
upper pole. Because it causes more trauma following two dilated tracts, it has not
gained general acceptance. Triangulation is another technique that creates a steep
cephalad angle to the upper pole and is technically more demanding and requires more
experience with percutaneous punctures. This technique is appropriate for most solitary
upper pole renal stones.
In the current study, access length was found as a practical criterion to choose access
tract, before performing PCNL for solitary upper pole renal stones. If the access length
is below 12 cm, we can choose subcostal upper pole approach and if it is above 12 cm,
it would be better to avoid this approach and choose supracostal approach. We think
that by considering this criterion preoperatively, we would be able to avoid many
redundant supracostal access and related complications. Another interesting finding
was that access length in many patients was below 12 cm (83% patients) that means a
little necessity for supracostal access. Further studies with more patients are advocated
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to evaluate this criterion, precisely. However, we only evaluate and find one criterion;
we hope other colleagues find better criteria to clarify this subject.
Conclusion
This study shows that for most solitary upper pole renal stones, we should not
necessarily choose the supracostal access; otherwise, we can use subcostal upper pole
access. In addition, access length is a new useful criterion for approach to solitary upper
pole renal stones. If access length is below 12 cm, we can perform subcostal access
and if is above 12 cm, it would be better to avoid subcostal access.
Acknowledgements
We are indebted to the Research Development Center of Sina Hospital for its support
and Mrs. Hoda Kameli for drawing figure of the manuscript.
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References
1.
Lingeman J, Matlaga B, Evan A. Surgical management of upper urinary tract
calculi. Campbell-Walsh urology 9th ed Philadelphia: Saunders. 2007:1465-80.
2.
Shaban A, Kodera A, El Ghoneimy MN, Orban TZ, Mursi K, Hegazy A. Safety
and efficacy of supracostal access in percutaneous renal surgery. J Endourol. 2008
Jan;22(1):29-34.
3.
Segura J. The role of percutaneous surgery in renal and ureteral stone removal.
The Journal of urology. 1989;141(3 Pt 2):780.
4.
Kapoor R, Solanki F, Singhania P, Andankar M, Pathak HR. Safety and efficacy
of percutaneous nephrolithotomy in the pediatric population. J Endourol. 2008
Apr;22(4):637-40.
5.
Aron M, Goel R, Kesarwani P, Seth A, Gupta N. Upper pole access for complex
lower pole renal calculi. BJU international. 2004;94(6):849-52.
6.
GOLIJANIN D, KATZ R, VERSTANDIG A, SASSON T, LANDAU E, MERETYK
S. The supracostal percutaneous nephrostomy for treatment of staghorn and complex
kidney stones. Journal of Endourology. 1998;12(5):403-5.
7.
Radecka E, Brehmer M, Holmgren K, Magnusson A. Complications Associated
with Percutaneous Nephrolithotripsy: Supra Versus Subcostal Access. Acta
Radiologica. 2003;44(4):447-51.
8.
Yadav R, Aron M, Gupta NP, Hemal AK, Seth A, Kolla SB. Safety of supracostal
punctures for percutaneous renal surgery. Int J Urol. 2006 Oct;13(10):1267-70.
11
9.
Raza A, Moussa S, Smith G, Tolley DA. Upper-pole puncture in percutaneous
nephrolithotomy: a retrospective review of treatment safety and efficacy. BJU Int. 2008
Mar;101(5):599-602.
10.
Gupta R, Kumar A, Kapoor R, Srivastava A, Mandhani A. Prospective evaluation
of safety and efficacy of the supracostal approach for percutaneous nephrolithotomy.
BJU international. 2002;90(9):809-13.
11.
Rehman J, Chughtai B, Schulsinger D, Adler H, Khan SA, Samadi D. A
percutaneous subcostal approach for intercostal stones. J Endourol. 2008
Mar;22(3):497-502.
12.
McAllister M, Lim K, Torrey R, Chenoweth J, Barker B, Baldwin DD. Intercostal
Vessels and Nerves are at Risk for Injury During Supracostal Percutaneous
Nephrostolithotomy. J Urol. 2011 Jan;185(1):329-34.
13.
Farrell T, Hicks M. A review of radiologically guided percutaneous nephrostomies
in 303 patients. Journal of Vascular and Interventional Radiology. 1997;8(5):769-74.
14.
Forsyth M, Fuchs E. The supracostal approach for percutaneous
nephrostolithotomy. The Journal of urology. 1987;137(2):197.
15.
Karlin G, Smith A. Approaches to the superior calix: renal displacement
technique and review of options. The Journal of urology. 1989;142(3):774.
16.
Munver R, Delvecchio FC, Newman GE, Preminger GM. Critical analysis of
supracostal access for percutaneous renal surgery. J Urol. 2001 Oct;166(4):1242-6.
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