Discussion
SULL is an effective surgical method with high stone-free rate for
treating ureteral stones, yet infectious complications are inevitable
(6,7). Infectious complications following URS may lead to an extended
period of hospital stay with an impact on the prognosis of patients,
increasing the potential risk for multiple organ dysfunction (7–9). As
a result, it is important to prevent infection-related complications in
order to minimize morbidity rates. In this review, the incidence of SIRS
was 1.7 % which is consistent with the rates stated in previous studies
(10–12).
There are several modifiable and non-modifiable factors mentioned in the
literature that may be used as predictors of SIRS. Higher SIRS rates
were correlated with larger stone burden, surgical time, infectious
stone, irrigation with an increased flow rate, small-caliber UAS, URS
preceding after obstructive pyelonephritis, a positive PBUC, and female
sex (7,8,13). Furthermore, history of previous urologic stone surgery,
history of recurrent UTIs, preoperative pyuria, preoperative acute
pyelonephritis, hydronephrosis, and the placement of a urethral
catheter, DJS or percutaneous nephrostomy were recognized as factors
increasing the risk for infectious complications in URS (14–17). In
both univariable and multivariable analysis conducted in our study;
stone burden, surgical time, and the history of recurrent UTI were
statistically significant predictors for SIRS.
Our research was not able to demonstrate the impact of factors in
certain cases such as URS preceding obstructive pyelonephritis, acute
pyelonephritis, and hydronephrosis due to the fact that all patients had
stone surgery as elective cases. Compared with the non-SIRS group, the
female sex rate in the SIRS group was higher, yet the difference was not
statistically significant. The presence of DJS preoperatively was not
identified as a predictive factor for SIRS in our study. We thought that
the reason for this result might be that patients who were placed DJ
stents due to obstructive uropathy were not included in the study. The
only reason for having a DJS preoperatively was passive dilatation in
our study. Additionally, this outcome may have occurred as the mean time
period for DJS insertion to achieve passive dilatation was less than 21
days (18).
Stone cultures for prediction of infectious complications following PNL
surgery and the management of postoperative antibiotic treatment were
found to have an increased value in recent years (19–21). The current
research revealed samples of preoperative bladder urine to be
insufficient in identifying microorganisms surrounding the stone because
the fragmented stone cultures were usually different from the stone
surface or PBUC (22).
In contrary to previous studies, no association was shown between renal
pelvic urine culture (RPUC), stone culture (SC) and sepsis or SIRS in
the study by Koras et al.(23). The common message of all the studies,
however, is that intraoperative cultures may be crucial for guidance on
antibiotic treatment postoperatively. In a study exploring the
association of RPUC and SC with SIRS following URS, it was stated that
PBUC was incompatible with RPUC and SC (9). Reconsideration of the
antibiotic therapy according to the results of the RPUC and SC was
recommended in cases of postoperative infectious complications (9).
Nevertheless, in the current study, 20 out of 23 patients with SIRS had
PBUC, RPUC or SC growth, and PBUC, RPUC and SC were observed to be
compatible in eight (40 %) patients. Furthermore, no growth was
observed in RPUC and SC in five (25%) patients, and only PBUC
positivity was found; postoperative antibiotic treatment was adjusted
according to the PBUC results. Since RPUC and SC may be considered as
time-consuming tests, it is clear that the value of PBUC may never be
underestimated. As we primarily aimed to assess the impact of the time
between PBUC and RIRS on SIRS, evaluating the effect of the duration
between PBUC and SULL more precisely, the positivity of PBUC was
incorporated as a variable for predicting SIRS in the study.
In countries with a high prevalence of urinary system stone disease in
tertiary referral institutions such as our clinic, waiting times are
extended in elective stone surgeries such as SULL. This leads to an
increase in the duration between PBUC and SULL. The lengthening of this
time interval raises questions in the minds of both patients and
doctors. Surgeons may become suspicious that as time increases,
re-infections may occur in those patients with a risk of UTI. It was
shown in our research that the time period between PBUC and SULL was not
a predictive factor for SIRS. Extending the waiting time for SULL may
increase the risk of complications caused by infection. The outcome
revealed in our study may be a result of the fact that factors such as
stone burden, surgical time and history of recurrent UTI, identified in
the literature as risk factors for infectious complications
postoperatively (8,14,24), were observed more frequently in SIRS
patients in comparison to patients with a normal postoperative period.
The possible impact of the lengthening the waiting time in the study may
have been obscured by these variables.
There are some limitations to our study. The operations were undertaken
by urology specialists and residents. Thus, the parameters depending on
the operator may be biased. The retrospective design was another
limitation of our study. In addition, this study only reveals the
experience of a single center.