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\begin{document}

\title{Effect of Age on Percutaneous Nephrolithotomy for Staghorn Renal Stones}



\author[1]{Murat Sahan}%
\author[1]{Serkan Yarımoğlu}%
\author[2]{Metin Savun}%
\author[3]{Onur Erdemoglu}%
\author[4]{Tansu Degirmenci}%
\affil[1]{Izmir Bozyaka Training and Research Hospital}%
\affil[2]{Siverek State Hospital}%
\affil[3]{Affiliation not available}%
\affil[4]{University of Health Sciences Izmir Bozyaka Education and Research Hospital}%


\vspace{-1em}



  
  \date{May 22, 2024}


\begingroup
\let\center\flushleft
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\maketitle
\endgroup





\selectlanguage{english}
\begin{abstract}
Objective: To evaluate the effect of age on the success and
complications of percutaneous nephrolithotomy(PCNL) in staghorn renal
stones. Material and Methods: The files of 182 patients who underwent
single-access PCNL for staghorn renal stones between 2012 and 2017 were
retrospectively analyzed.The patients were divided into two groups
according to their age: those aged \textless{}65 years were defined as
Group-1 and those aged [?]65 years as Group-2.The demographic
characteristics and perioperative and postoperative results of the
patients were compared between the two groups.Postoperative detection of
stones\textgreater{}4 mm was defined as residual stones.Complications
were classified according to the Clavien scoring system. Results: Of the
patients with staghorn renal stones,139 were in Group-1 and 43 were in
Group-2. The mean age of the patients was 43.9\selectlanguage{ngerman}±10.6 years for Group-1
and 67.8±2.1 years for Group-2(p=0.001).The mean stone size in Group-1
and Group-2 was 899±292 and 1,008±208 mm2, respectively(p=0.736). When
we evaluated the postoperative results, we observed that the amount of
hemoglobin drop was statistically significantly higher in
Group-1(p=0.001). However, the need for blood transfusion was higher in
Group-2 than in Group-1(18.6\% and 7.2\%, respectively). The stone-free
rate was 54.7\% in Group-1 and 67.4\% in Group-2(p=0.139). According to
the evaluation of the overall complication rates,34.5\% of the patients
in Group-1 and 46.5\% of those in Group-2 developed
complications(p=0.206). When we examined the subgroups of complications
according to the Clavien scoring system, the rate of minor complications
was found to be 22.3\% in Group-1 and 41.9\% in Group-2,and the
difference was statistically significant(p=0.012). The major
complication rates were determined as 4.7\% and 12.2\% for Group-1 and
Group-2,respectively(p=0.155). The number of patients with Clavien
grade-2 complications was statistically higher in the elderly patient
group(p=0.019). Conclusion: PCNL can be used as an effective and safe
treatment method in the treatment of complex stones in elderly patients%
\end{abstract}\selectlanguage{ngerman}%



\sloppy


\textbf{ABSTRACT}

\textbf{Objective:}

To evaluate the effect of age on the success and complications of
percutaneous nephrolithotomy(PCNL) in staghorn renal stones.

\textbf{Material and Methods:}

The files of 182 patients who underwent single-access PCNL for staghorn
renal stones between 2012 and 2017 were retrospectively analyzed.The
patients were divided into two groups according to their age: those aged
\textless{}65 years were defined as Group-1 and those aged [?]65 years as
Group-2.The demographic characteristics and perioperative and
postoperative results of the patients were compared between the two
groups.Postoperative detection of stones\textgreater{}4 mm was defined
as residual stones.Complications were classified according to the
Clavien scoring system.

\textbf{Results:}

Of the patients with staghorn renal stones,139 were in Group-1 and 43
were in Group-2. The mean age of the patients was 43.9\selectlanguage{ngerman}±10.6 years for
Group-1 and 67.8±2.1 years for Group-2(p=0.001).The mean stone size in
Group-1 and Group-2 was 899±292 and 1,008±208 mm\textsuperscript{2},
respectively(p=0.736).

When we evaluated the postoperative results, we observed that the amount
of hemoglobin drop was statistically significantly higher in
Group-1(p=0.001). However, the need for blood transfusion was higher in
Group-2 than in Group-1(18.6\% and 7.2\%, respectively). The stone-free
rate was 54.7\% in Group-1 and 67.4\% in Group-2(p=0.139). According to
the evaluation of the overall complication rates,34.5\% of the patients
in Group-1 and 46.5\% of those in Group-2 developed
complications(p=0.206).

When we examined the subgroups of complications according to the Clavien
scoring system, the rate of minor complications was found to be 22.3\%
in Group-1 and 41.9\% in Group-2,and the difference was statistically
significant(p=0.012). The major complication rates were determined as
4.7\% and 12.2\% for Group-1 and Group-2,respectively(p=0.155). The
number of patients with Clavien grade-2 complications was statistically
higher in the elderly patient group(p=0.019).

\textbf{Conclusion:}

PCNL can be used as an effective and safe treatment method in the
treatment of complex stones in elderly patients.

\textbf{Keywords:} Percutaneous nephrolithotomy, Staghorn renal stone,
Clavien scoring system, Age

\textbf{What's already known about this topic?}

Currently, percutaneous nephrolithotomy are the most favored treatment
option for staghorn renal stones. However, there are concerns related to
the safe applicability of PCNL in geriatric patients with staghorn
stones, who have bleeding tendency and low cardiopulmonary performance.

\textbf{What does this article add?}

This study showed that PCNL could be effectively and safely applied in
the elderly population for the treatment of staghorn renal stones.
However, since minor complications after PCNL are seen at a higher rate
in this patient group.

\textbf{Introduction:}

Globally, individuals aged 65 and over are defined as the `elderly
population' (1). Especially in developed and developing countries, the
decrease in birth rates, as well as the prolongation of life expectancy
at birth and advanced age have led to a relative increase in the elderly
population and its share in the total population. As a result of this
increase, more elderly patients require treatment due to urinary system
stones. Staghorn stones are of particular concern in this age group
because the treatment of such stones may require lengthy and multiple
procedures and has a high complication rate.

Staghorn stones are branching and usually infected stones that cover a
large part of the collecting system (2). Failure to achieve stone-free
status may lead to the complete loss of function and sepsis in the
kidney by destroying the renal parenchyma. Guidelines recommend
percutaneous nephrolithotomy (PCNL) as the gold standard treatment
modality for renal stones \textgreater{} 2 cm (3). Overall stone-free
rates in patients with PCNL reach 96.1\% (4). However, since multiple
percutaneous accesses may be required to remove all stone branches in
staghorn stones, it is very difficult to achieve stone-free status in a
single session in these patients (5). Therefore, as reported in previous
studies, stone-free rates in staghorn stones can decrease to 56.9\% (6).
In addition to these low stone-free rates after PCNL, staghorn stones
also have high complication rates. In a prospective randomized study,
the intraoperative complication rate of PCNL applied in the treatment of
staghorn stones was found to be 16.3\%, and the postoperative major
complication rate was determined as 18.6\% (7)

There are concerns related to the safe applicability of PCNL in
geriatric patients with staghorn stones, who have bleeding tendency and
low cardiopulmonary performance. Therefore, in this study, we aimed to
compare the results between elderly and younger patients who underwent
PCNL for treatment of staghorn renal stones.

\textbf{Material and Methods:}

This is a retrospective analysis of patients who underwent PCNL for
staghorn renal stones at the Ministry of Health Izmir Bozyaka Training
and Research Hospital between April 2011 and January 2017. All the data
of the patients were obtained from their electronic medical records.
Patients with a history of neuromuscular disease, congenital kidney
anomalies, coagulopathy, skeletal deformity, and solitary kidneys, cases
requiring multiple accesses, and patients without staghorn stones were
excluded from the study. A total of 182 staghorn stones were divided
into two groups according to patient age: those aged \textless{}65 years
old were defined as Group-1 and those aged \selectlanguage{english}[?]65 years as Group-2. The
demographic, perioperative and postoperative data were compared between
these two groups.

All the patients were evaluated preoperatively using standard
non-contrast abdominal computed tomography (CT). The patients'
demographic characteristics such as gender and body mass index, and
preoperative characteristics, including operation side and history,
stone burden, metabolic syndrome (presence of at least two of the
following diseases: diabetes mellitus, hypertension, hyperlipidemia
and/or obesity), and stone density were recorded. In addition,
intraoperative and postoperative results (operation time, fluoroscopy
time, nephroscopy time, length of hospital stay, calyx accessed,
complications, and stone-free status) were examined. Postoperative
complications were evaluated according to the Clavien scoring system (8)
and divided into two groups as minor (grades I and II) and major (grades
III to V).

After the urine culture of the patients was confirmed to be negative,
they were taken to the operation room. Ceftriaxone was administered to
the patients as prophylaxis before the operation and continued until the
nephrostomy tube was removed. No nephrotoxic drug was used in any of the
patients before, during or after the operation.

Stone burden was calculated in square millimeters in all patients
(length x width x \selectlanguage{greek}π \selectlanguage{english}x 0.25, where 3.14 was taken as the mathematical
constant) (9). For staghorn stones, this calculation was performed
separately for each calyceal stone and the sum of all values was
accepted as the result. All PCNL operations were performed by
experienced urologists. Success was considered as complete stone-free
status or detection of \textless{}4 mm stones on control CT performed at
the first postoperative month.

PCNL procedure

After placing 5 or 6 F ureter catheters in the renal pelvis in the
lithotomy position under general anesthesia, subcostal or intercostal
access was achieved in all patients with an 18-gauge needle under
fluoroscopy in the prone position depending on the location of the stone
and the anatomy of the kidney. The entry site was dilated up to 30 Fr
using Amplatz dilators, and the collecting system was entered with a
nephroscope. The stones were fragmented with a pneumatic lithotriptor
(Vibrolith; Elmed, Ankara, Turkey). A 14 F nephrostomy tube was inserted
postoperatively and antegrade pyelography was performed in all patients.
If fever or significant hematuria was not detected, nephrostomy was
clamped on the first or second postoperative day. After clamping, the
nephrostomy tube was removed if there was no leakage from the
nephrostomy edges and no renal colic.

Statistical Analysis

Statistical Package for the Social Sciences (SPSS IBM Corp.; Armonk, NY,
USA) version 22 software package was used to analyze the data. The
independent-samples t-test, chi-square test, and Fisher's exact test
were used to compare the two groups. Quantitative data were expressed as
mean \selectlanguage{ngerman}± standard deviation values in tables. Categorical data were
presented as numbers (frequency) and percentages (\%). Data were
analyzed at a 95\% confidence level, and p value was considered
significant if less than 0.05.

\textbf{Results:}

There were 139 patients in Group-1 and 43 patients in Group-2. The mean
ages of the patients were 43.9 ± 10.6 and 67.8 ± 2.1 years in Group-1
and Group-2, respectively (p = 0.001). The mean stone size was 899 ± 292
mm\textsuperscript{2} in Group-1, it was 1,008 ± 208
mm\textsuperscript{2} in Group-2 (p = 0.736). The two groups were
similar in terms of patient and stone characteristics (gender, body mass
index, presence of metabolic syndrome, operation side, operation
history, and stone density). Demographic data and stone characteristics
are shown in detail in Table 1.

When we examined the operative data, we determined that the durations of
operation, nephroscopy and fluoroscopy were similar between the groups
(p = 0.968, p = 0.149, and p = 0.342 respectively). The calyx used for
entry also did not significantly different between the two groups (p =
0.479). Detailed operative data are shown in Table 2.

When we evaluated the postoperative results, we observed that the amount
of hemoglobin drop was statistically higher in Group-1 (p = 0.001).
However, the need for blood transfusion was found to be higher in
Group-2 than in Group-1 (18.6\% and 7.2\%, respectively). There was no
significant difference between the two groups in terms of length of
hospital stay and duration of nephrostomy tube use (p = 0.855 and p =
0.352, respectively). The stone-free rate was calculated as 54.7\% in
Group-1 and 67.4\% in Group-2. No statistically significant difference
was found between the two groups in terms of the stone-free rate (p =
0.139). Concerning the overall complication rates, 34.5\% of patients in
Group-1 and 46.5\% of those in Group-2 were observed to develop
complications. There was no statistically significant difference between
the two groups in relation to the overall complication rates (p =
0.206). Postoperative complications and related results are shown in
detail in Table 3.

When we examined the subgroups of complications according to the Clavien
scoring system, the rate of minor complications was found to be 22.3\%
in Group-1 and 41.9\% in Group-2, indicating a statistically significant
difference (p = 0.012). The major complication rates were determined as
4.7\% and 12.2\% in Group-1 and Group-2, respectively (p = 0.155). In
addition, the rate of Clavien grade-2 complications was statistically
higher in the elderly group (p = 0.019). The details of the
complications according to the Clavien scoring system are shown in Table
4.

\textbf{Discussion:}

The increase in the average life expectancy and aging population has
resulted in more renal stones being detected in geriatric patients. It
is important to determine the most appropriate method when treating
renal stones in elderly patients due to age-related cardiovascular and
pulmonary system deterioration and presence of multiple comorbidities.
In elderly patients with multiple comorbidities, observation may be an
option for asymptomatic small stones. However, in elderly patients,
stone growth is observed to occur over a shorter time, and urinary tract
infection causes pain that requires obstruction and analgesics (10),
adversely affecting their kidney functions. Although PCNL is accepted as
an effective and safe method in large renal stones, it can result in
major complications. Skolarikos and de la Rosette reported that the rate
of major complications after PCNL was 0.9-4.7\% for septicemia,
0.6-1.4\% for renal bleeding requiring an intervention, 2.3-3.1\% for
pleural injury, and 0.2-0.8\% for colonic injury (11). Changes in the
cardiorespiratory reserve of elderly patients make them less tolerant to
bleeding or septic complications (12). Therefore, a detailed evaluation
and a careful approach are required in the treatment of renal stones in
elderly patients.

Despite advances in instrumentation and technology, staghorn stones are
difficult to manage. In a study retrospectively reviewing 42 PCNL
procedures performed on 33 patients aged 65 years and older compared
with younger patients (47\% of the stones were staghorn), 82\% (27/33)
of the patients were determined to achieve stone-free status or have
fragments smaller than 5 mm at three months after surgery. In this
study, PCNL was shown to be a safe and effective treatment for elderly
patients, even in the presence of complex renal stones; however, a
higher rate of transfusion was required in this group (13). \selectlanguage{polish}Ş\selectlanguage{english}ahin et al.
reported the PCNL results of 27 patients aged over 60 years and compared
them to 178 PCNL procedures performed in 166 younger patients at the
same time interval (14). Only 25\% of the patients had staghorn renal
stones, and the success rate (stone-free status or fragments smaller
than 4 mm) was 89\% for the elderly and 92\% for the younger patients.
In contrast to previous studies reporting higher stone-free rates
(78-93\%) after PCNL in staghorn renal stones (5,15), the success rates
obtained from the current study including only complete staghorn stones
were found to be 67.4\% and 54.7\%, for the elderly and younger groups,
respectively. This lower rate of success can be explained by technical
limitations, such as the exclusion of partial staghorn stones, use of
only one access point for each patient, lithotripsy being performed only
with a pneumatic lithotripter, and not using a flexible nephroscope.
Similar to our study, Kuzgunbay et al., who performed 47 PCNL procedures
in 45 patients aged 65 years with complete staghorn stones and compared
their data to 37 younger patients, found the success rate after the
first procedure as 53\% in the elderly group and 37.8\% in the control
group (16).

In our study, in which only complete staghorn stones were included,
there was no significant difference between the stone sizes of the
elderly and younger patients, which shows the comparability of the two
groups in terms of stone burden. Furthermore, length of hospital stay,
operation and fluoroscopy durations, and success rate were found to be
similar in the elderly and younger groups. Therefore, we consider that
advanced age does not have a negative effect on intraoperative
parameters and postoperative outcomes in complex stones. However, in our
study, while the decrease in hemoglobin was significantly higher in
younger people (1.9 \selectlanguage{ngerman}± 1.3 g/dl versus 1.3 ± 1.2 g/dl, p = 0.001), the
rate of transfusion requirement was moderately higher in the elderly
(7.2\% versus 18.6 \%). This suggests that the rate of transfusion was
higher in the elderly relative to the decrease in hemoglobin. The higher
transfusion rate in the elderly indicates that they have lower tolerance
to hemoglobin drop. Stoller et al. found higher blood transfusion rates
after PCNL in elderly patients with complex renal stones (13). \selectlanguage{polish}Ş\selectlanguage{english}ahin et
al. reported the transfusion rates after PCNL as 21\% in elderly
patients and 18\% in younger patients (14). In another study, the
transfusion rate after PCNL in staghorn renal stones was detected as
10.6\% in the elderly and 13.5\% in the younger group, while the
hemoglobin change was 1.46 \selectlanguage{ngerman}± 1.29 g/dl and 1.70 ± 1.33 g/dl,
respectively (16).

Percutaneous nephrolithotomy is recognized as an effective and safe
treatment option for large renal stones. Although the efficacy of the
procedure has been proven, complication rates of up to 83\% have been
reported in the literature, including bleeding requiring transfusion
(7\%), organ damage (0.4\%), and infectious events (up to 33\%) (17,18).
Elderly patients tend to have more comorbidities, making them more
vulnerable to fatal bleeding and septic complications (19). In a study
by Okeke et al., the overall complication rate after PCNL was
significantly higher in elderly patients compared to younger patients
(20). However, Karami et al. reported that age alone was not a
predictive factor for high complication rates (21). In another study, no
major complications were observed after PCNL in staghorn renal stones in
the elderly and younger population, and their minor complication rates
were similar (16). In contrast, in our study, there was a higher rate of
minor complications, such as bleeding requiring transfusion in eight and
postoperative fever requiring antibiotic change in seven of the 43
patients in the elderly group, while sepsis, pneumothorax and bowel
injury were not observed in either group. This suggests that elderly
patients are less tolerant of bleeding and less resistant to infectious
events because they are more prone to having comorbidities. To our
knowledge, this is the first study to separately evaluate post-PCNL
complications in elderly patients with staghorn renal stones according
to the Clavien-Dindo classification.

There are some limitations to our study. First, it had a retrospective
design and a limited number of patients. Second, there was no long-term
comparison of surgical complications. Finally, there is a need for
prospective studies with a larger series of geriatric patients with
staghorn stones, focusing specifically on complications, as well as
evaluating their medical complications.

\textbf{Conclusion:}

This study showed that PCNL could be effectively and safely applied in
the elderly population for the treatment of staghorn renal stones.
However, since minor complications after PCNL are seen at a higher rate
in this patient group, it is necessary to be more cautious in terms of
possible complication development.

\textbf{Funding:} None.

\textbf{Author Disclosure Statement:}

\textbf{Conflict of interest:} None

\textbf{Ethical Standards:} Informed consent was obtained
pre-operatively from all of our patients

which were included in our study.

\textbf{Ethical compliance:} All procedures performed in studies
involving human participants were

in accordance with the ethical standards of the institutional and/or
national research

committee and with the 1964 Helsinki declaration and its later
amendments or comparable

ethical standards.

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