Abstract
Objectives
We aimed to investigate the effect of prolonged time from diagnosis to treatment (TDT) on surgical outcomes in patients undergoing percutaneous nephrolithotomy (PNL).
Methods
This study included a total of 544 patients who underwent PNL in our clinic between November 2017 and November 2021. Clinicodemographical, radiological, and perioperative data of the patients were recorded. The stone-free rate as assessed by abdominal computed tomography at 3 months was estimated. The possible relation of the stone-free rate and perioperative complications with TDT was examined.
Results
The median age was 48 (range, 38–58) years, the median stone size was 405 (range, 250–700) mm2, and the median stone density was 1,000 (range, 730–1,221) Hounsfield units. The median TDT was 75 (range, 42–133) days. Twenty-seven patients (5.0%) required perioperative blood transfusion (PBT). There was a statistically significant correlation between TDT and the need for PBT (p=0.022). However, there was no significant correlation between TDT and stone-free rate (p>0.05). Using a cutoff value of 90.5 days, TDT could predict the need for PBT with 59.3% sensitivity and 60% specificity.
Conclusion
Our study results suggest that the need for PBT increases in patients undergoing PNL longer than 90.5 days after the diagnosis. However, further large-scale, prospective studies are warranted to elucidate the effect of prolonged TDT on surgical outcomes in this patient population.
Keywords: : Blood transfusion, percutaneous nephrolithotomy, time to treatment
Urinary stone disease is a major health issue with an increasing prevalence worldwide and is associated with acute or chronic renal failure if left untreated.[1,2] Percutaneous nephrolithotomy (PNL) is the first-line treatment, particularly in patients with kidney stones of >2 cm, and many studies have examined the stone-free status and associated complications in this group of patients. The main factors for stone-free and complication rates after PNL include stone-related factors such as the size, location, composition, and number of stones, the presence of hydronephrosis, patient-related factors such as body mass index, comorbidities, the presence of renal abnormalities, and health-care-related factors such as annual case volume of the center.[3-6]
The novel coronavirus disease-2019 (COVID-19) pandemic had devastating consequences worldwide, as well as post-poning elective urological surgeries. The European Association of Urology (EAU) guidelines recommended ureteral stenting or nephrostomy for obstructing and complicated urinary stones and post-poning other procedures until the pandemic was controlled.[7] In particular, the prognosis of patients who had obstructing urinary stones, but were unable to be admitted to health-care centers during the lockdowns still remains unclear.
Prolonged time from diagnosis to treatment (TDT) has been shown to decrease overall survival in certain types of cancer.[8,9] However, to the best of our knowledge, there is no study evaluating the effect of prolonged TDT on surgical outcomes in patients with urinary stones. In the present study, we hypothesized that prolonged TDT might decrease the stone-free rates and increase perioperative complications in patients undergoing PNL. We, therefore, aimed to investigate the effect of prolonged TDT on surgical outcomes in patients undergoing PNL.
Methods
Study Design and Patient Selection
This single-center, retrospective study was conducted at the department of urology, kidney stone center of a tertiary referral hospital between November 2017 and November 2021. The study was approved by the local Ethics Committee (No: 513, Date: May 20, 2021) and conducted in accordance with the principles of the Declaration of Helsinki.
Medical data of a total of 920 patients who underwent PNL during the study period were analyzed. All patients were informed about the nature of the procedure and written informed consent was obtained. Data including demographic, clinical, radiological, and perioperative characteristics of the patients were recorded. As standard, non-enhanced abdominal computed tomography (CT) was used to diagnose urinary stones and to assess stone-free status at the post-operative 3rd month. Clinically, insignificant residual stones were defined as stone fragments of <10 mm2 on CT at the post-operative 3rd month. Patients aged <18 years (n=37), those with a solitary kidney (n=24), having pre-operative nephrostomy or ureteral stenting (n=35), undergoing endoscopic stone extraction from the same side within the past 6 months (n=23), undergoing tubeless procedures (n=150), and having missing radiological data (n=107) were excluded from the study. Finally, a total of 544 patients who met the inclusion criteria were recruited.
Statistical Analysis
Statistical analysis was performed using the Statistical Package for Social Sciences version 22.0 software (IBM Corp., Armonk, NY, USA). The Kolmogorov–Smirnov and Shapiro–Wilk tests were used to check the normality of data for quantitative variables. Continuous variables were expressed in the median and interquartile range, whereas categorical variables were expressed in number and frequency. The Mann–Whitney U and Kruskal–Wallis tests were used to determine homogeneity, independence, and the differences between related groups. The correlation coefficient and statistical significance for the relationships between TDT and perioperative stone characteristics and clinical findings were calculated using the Spearman correlation analysis. Diagnostic scanning tests including sensitivity, specificity, positive predictive value, negative predictive value, and receiver operating characteristic analysis were carried out to identify the predictive value of TDT for the need for blood transfusion. A two-sided P value of < 0.05 was considered statistically significant.
Results
A total of 544 patients who underwent PNL were included in this study. The median age was 48 (range, 38–58) years. Of the patients, 65 (11.9%) had renal abnormalities (Table 1). The median stone size was 405 (range, 250–700) mm2, and the median stone density was 1,000 (range, 730–1,221) Hounsfield units. The median nephrostomy dwell time was 2 (range, 1–3) days, and the median length of hospital stay was 2 (range, 2–3) days. The median TDT was 75 (range, 42–133) days (Table 2). Of the patients, 28 (5.1%) had post-operative fever and 17 (3.1%) had perirenal hematoma. The median hemoglobin drop was 1.90 (range, 1.25–2.85) g/dL. Blood transfusion was applied to patients with perioperative hemoglobin level below approximately 9 g/dL. Twenty-seven (5.0%) of the patients required perioperative blood transfusion (PBT) (Table 3).
Table 1.
Demographic and clinical characteristics of patients
| Median (IQR) | n | % | |
|---|---|---|---|
| Age (year) | 48 (38–58) | ||
| Sex | |||
| Female | 206 | 37.9 | |
| Male | 338 | 62.1 | |
| BMI (kg/m2) | 26.3 (24.7–30.4) | ||
| ASA Class | |||
| ASA-1 | 407 | 74.8 | |
| ASA-2 | 119 | 21.9 | |
| ASA-3 | 16 | 2.9 | |
| ASA-4 | 2 | 0.4 | |
| Pre-operative creatinine level (mg/dL) | 0.80 (0.70–0.95) | ||
| Diabetes mellitus | |||
| No | 448 | 82.4 | |
| Yes | 96 | 17.6 | |
| High blood pressure | |||
| No | 413 | 75.9 | |
| Yes | 131 | 24.1 | |
| Coronary artery disease | |||
| No | 506 | 93.0 | |
| Yes | 38 | 7.0 | |
| Chronic kidney disease | |||
| No | 535 | 98.5 | |
| Yes | 8 | 1.5 | |
| Chronic obstructive pulmonary disease | |||
| No | 522 | 96.0 | |
| Yes | 22 | 4.0 | |
| Cerebrovascular disease | |||
| No | 535 | 98.3 | |
| Yes | 9 | 1.7 | |
| Renal abnormality | |||
| No | 479 | 88.1 | |
| Yes | 65 | 11.9 | |
| Previous stone surgery | |||
| No | 313 | 57.5 | |
| Yes | 231 | 42.5 |
IQR: interquartile range; BMI: body mass index; ASA: American Society of Anesthesiologists
Table 2.
Clinical, radiological, and operative data of patients
| n | % | Median (IQR) | |
|---|---|---|---|
| Side | |||
| Right | 267 | 49.1 | |
| Left | 277 | 50.9 | |
| Stone size (mm2) | 405 (250–700) | ||
| Stone CT density (HU) | 1000 (730–1221) | ||
| Skin-to-stone distance (mm) | 88 (74–102) | ||
| Hydronephrosis | |||
| No | 363 | 66.7 | |
| Yes | 181 | 33.3 | |
| Staghorn calculus | |||
| No | 478 | 87.9 | |
| Yes | 66 | 12.1 | |
| Number of stones | |||
| Solitary | 199 | 36.6 | |
| Multiple | 345 | 63.4 | |
| Stone location | |||
| Lower calyx | 88 | 16.2 | |
| Middle calyx | 21 | 3.9 | |
| Upper calyx | 13 | 2.4 | |
| Renal pelvis | 143 | 26.3 | |
| Multiple calyx | 278 | 51.1 | |
| Guy Stone Score | |||
| GSS-1 | 166 | 30.5 | |
| GSS-2 | 242 | 44.5 | |
| GSS-3 | 93 | 17.1 | |
| GSS-4 | 43 | 7.9 | |
| CROES Score | 215 (180–282) | ||
| S.T.O.N.E. Score | 7 (6–8) | ||
| Surgery duration (min) | 90 (70–120) | ||
| Access number | |||
| 1 | 514 | 94.7 | |
| 2 | 28 | 5.2 | |
| 3 | 1 | 0.2 | |
| Intercostal access | |||
| No | 493 | 90.8 | |
| Yes | 50 | 9.2 | |
| Nephrostomy duration (day) | 2 (1–3) | ||
| Length of hospital stay (day) | 2 (2–3) | ||
| Time from Diagnosis to Treatment (day) | 75 (42–133) |
IQR: Interquartile range; CT: Computed tomography; HU: Hounsfield unit; PNL: Percutaneous nephrolithotomy
Table 3.
Post-operative clinical information of patients
| Median (IQR) | n | % | |
|---|---|---|---|
| Post-operative fever | |||
| No | 516 | 94.9 | |
| Yes | 28 | 5.1 | |
| Perioperative hemoglobin drop (g/dL) | 1.90 (1.25–2.85) | ||
| Perioperative blood transfusion | |||
| No | 517 | 95.0 | |
| Yes | 27 | 5.0 | |
| Post-operative hematoma | |||
| No | 527 | 96.9 | |
| Yes | 17 | 3.1 | |
| Post-operative urinoma | |||
| No | 542 | 99.6 | |
| Yes | 2 | 0.4 | |
| Post-operative angioembolization | |||
| No | 541 | 99.4 | |
| Yes | 3 | 0.6 | |
| Post-operative ureteral stenting | |||
| No | 517 | 95.0 | |
| Yes | 27 | 5.0 | |
| Perioperative complication (Clavien-Dindo) | |||
| No | 368 | 67.7 | |
| Clavien-Dindo-I | 93 | 17.1 | |
| Clavien-Dindo-II | 49 | 9.0 | |
| Clavien-Dindo-IIIA | 24 | 4.4 | |
| Clavien-Dindo-IIIB | 4 | 0.7 | |
| Clavien-Dindo-IVA | 5 | 0.9 | |
| Clavien-Dindo-IVB | 0 | 0.0 | |
| Clavien-Dindo-V | 1 | 0.2 | |
| Emergency visit after discharge | |||
| No | 515 | 94.7 | |
| Yes | 29 | 5.3 | |
| Stone-free status | |||
| No | 191 | 35.1 | |
| Yes | 353 | 64.9 |
IQR: Interquartile range
There was a statistically significant correlation between TDT and the need for PBT (p=0.022). However, there was no significant correlation between TDT and stone-free rate and other perioperative complications (p>0.05) (Tables 4 and 5). Using a cutoff value of 90.5 days, TDT could predict the need for PBT with 59.3% sensitivity and 60% specificity (Fig. 1).
Table 4.
Comparison of perioperative complications and stone-free status according to time from diagnosis to treatment
| Time from diagnosis to treatment (day) | ||
|---|---|---|
| Median (IQR) | p | |
| Post-operative Fever | ||
| No | 74 (42–133) | 0.147 |
| Yes | 94 (60–159) | |
| Perioperative Blood Transfusion | ||
| No | 72 (42–130) | 0.022* |
| Yes | 113 (65–153) | |
| Post-operative Hematoma | ||
| No | 74 (42–133) | 0.426 |
| Yes | 97 (44–148) | |
| Post-operative Urinoma | ||
| No | 76 (42–133) | 0.595 |
| Yes | 60 (52–67) | |
| Post-operative Angioembolization | ||
| No | 75 (42–133) | 0.903 |
| Yes | 96 (36–133) | |
| Post-operative Ureteral Stent Insertion | ||
| No | 74 (42–133) | 0.933 |
| Yes | 81 (42–146) | |
| Perioperative Complication (Clavien-Dindo) | ||
| No | 64 (38–116) | 0.324b |
| Clavien-Dindo-I | 81 (43–134) | |
| Clavien-Dindo-II | 98 (56–148) | |
| Clavien-Dindo-IIIA | 82 (32–137) | |
| Clavien-Dindo-IIIB | 62 (55–71) | |
| Clavien-Dindo-IVA | 72 (59–74) | |
| Clavien-Dindo-IVB | ||
| Clavien-Dindo-V | 83 (83–83) | |
| Emergency Visit After Discharge | ||
| No | 75 (43–133) | 0.865 |
| Yes | 77 (35–133) | |
| Stone-Free Status | ||
| No | 80 (45–135) | 0.169 |
| Yes | 71 (42–130) | |
Mann–Whitney U test; b: Kruskal–Wallis test; *: p<0.05; IQR: Interquartile range
Table 5.
Correlation analysis between time from diagnosis to treatment and perioperative stone characteristics and clinical findings
| Pre-operative Creatinine (mg/dL) | Hydronephrosis | Stone Size (mm2) |
Stone Density (HU) | Number of Calyx | ||
|---|---|---|---|---|---|---|
| Time From Diagnosis to Treatment (day) | Correlation Coefficient | −0.090* | −0.090* | −0.060 | −0.039 | 0.011 |
| Sig. (2-tailed) | 0.035 | 0.036 | 0.162 | 0.370 | 0.805 | |
| n | 544 | 544 | 544 | 544 | 544 | |
| Stone Number | Staghorn Calculus | Surgery Duration (min) |
Hospital Stay
(day) |
Nephrostomy Duration (day) | ||
| Time From Diagnosis to Treatment (day) | Correlation Coefficient | 0.090* | −0.036 | −0.003 | 0.003 | 0.053 |
| Sig. (2-tailed) | 0.035 | 0.398 | 0.946 | 0.945 | 0.221 | |
| n | 544 | 544 | 541 | 544 | 544 | |
| Intercostal Access | Tract Number | Post-operative Fever | Perioperative Haemoglobin Decline (gr/dL) | Perioperative Blood Transfusion | ||
| Time From Diagnosis to Treatment (day) | Correlation Coefficient | 0.034 | −0.004 | 0.062 | −0.004 | 0.098* |
| Sig. (2-tailed) | 0.429 | 0.932 | 0.147 | 0.929 | 0.022 | |
| n | 543 | 543 | 544 | 544 | 544 | |
| Post-operative Urinoma | Post-operative Angioembolization | Perioperative Complication (Clavien-Dindo) | Emergency Visit After Discharge | Stone Free Status | ||
| Time From Diagnosis to Treatment (day) | Correlation Coefficient | −0.023 | 0.005 | 0.084* | −0.007 | −0.059 |
| Sig. (2-tailed) | 0.595 | 0.903 | 0.049 | 0.866 | 0.169 | |
| n | 544 | 544 | 544 | 544 | 544 | |
Spearman’s Correlations; *: Correlation is significant at the 0.05 level (2-tailed); HU: Hounsfield Unit
Figure 1.
ROC curve analysis for time from diagnosis to treatment in patients receiving blood transfusion.
Discussion
The impact of delays in elective surgeries during the COVID-19 pandemic and prolonged TDT on endourological stone management has raised many concerns. In the present study, we investigated the effect of prolonged TDT on surgical outcomes in patients undergoing PNL and to evaluate stone-free and complication rates in this group of patients. Our study results showed that a TDT of longer than 90.5 days increased the need for PBT. We believe that this study would provide an additional contribution to the literature, particularly to decrease the PBT rates in patients undergoing PNL, which is one of the main concerns for these patients.
In a study, Yamaguchi et al.[10] compared tract dilation methods of PNL in over 5,000 patients and reported that the need for PBT was significantly higher in the balloon dilation group compared to the telescopic/serial dilator group. Using a 24-Fr and 30-Fr tract size in the balloon dilation group, the blood transfusion rates were 5.6% and 7.2%, respectively. In the current study, we used a 30-Fr tract size for balloon dilation. The blood transfusion rate was 5%, and the angioembolization rate was 0.6% in our study. In the study of Yamaguchi et al.[10] the transfusion rate was relatively high which can be attributed to the fact that the study was multicenter and low-volume centers (25 cases/year) were included. In our center, the annual case number was 200 in the pre-pandemic period and 90 during the pandemic with an annual case number of more than 50 for each endourologist. In another study, Akman et al.[11] evaluated the factors affecting bleeding during PNL focusing on a single surgeon’s experience. They used a 30-Fr tract size for 649 PNL procedures and the overall blood transfusion rate was 10.8% and the angioembolization rate was 1.4% which are higher than our findings. The relatively higher transfusion rate in the surgeon’s first 100 cases, and the higher rates of staghorn calculus and multiple access (28% and 19.2%, respectively) may explain this difference. In addition, Srivastava et al.[12] evaluated bleeding complications of PNL and identified possible predictors. The authors reported an overall blood transfusion rate of 12.3%. The high blood transfusion rate in this study can be explained by the enrollment of patients with chronic renal failure and a high number of simultaneous bilateral PNL cases. In our study, patients with chronic renal failure and those undergoing simultaneous bilateral PNL were excluded.
One of the main concerns in PNL is the effect of prolonged TDT on the kidney. Due to the lack of adequate data on this subject, neither physicians nor patients have enough information about the adverse consequences of prolonged TDT on renal functions, stone-free rates, and complications. As with all elective surgeries, the COVID-19 pandemic led to prolonged TDT for urinary stones. The EAU guidelines recommended urinary diversions such as ureteral stenting or nephrostomy for obstructing and complicated urinary stones.[7] However, prolonged stent or nephrostomy dwell time has been shown to be associated with bacteremia, pyelonephritis, and urosepsis.[13-15] Currently, the effects of prolonged TDT on surgical outcomes in patients scheduled for PNL for uncomplicated urinary stones still remain to be elucidated. In a systematic review, Assad et al.[16] evaluated the impact of delaying acute kidney stone surgery on the outcomes in patients with symptomatic, uncomplicated urinary stones. They found that upfront ureteroscopy instead of ureteral stenting and early (within 12–72 h) extracorporeal shockwave lithotripsy was associated with less admissions to the emergency department, medical imaging examinations, and upper urinary tract diversions. However, the main limitation was the lack of evaluation of the direct effects of post-ponement of surgical procedures on the outcomes in any of the studies included. Furthermore, none of the studies provided data regarding the timing of PNL. In our study, we excluded patients who underwent ureteral stenting or nephrostomy due to severe hydronephrosis, acute pyelonephritis, severe renal colic, or acute renal failure, which may all affect the results directly. We found a statistically significant correlation between TDT and the need for PBT. A TDT of longer than 90.5 days increased the need for PBT. However, there was no significant relationship between TDT and stone-free rates at 3 months and overall complication rates.
In the present study, the rate of patients with comorbidities that pose a risk for urolithiasis, such as diabetes, hypertension, and coronary artery disease, was high in consistent with the literature.[17] Especially during the pandemic period, these patients may have been less preferred for elective surgery, due to factors such as longer hospital stays and more need for intensive care unit, and therefore, TDT of these patients may have prolonged.[18] In addition, the relationship between perioperative hemorrhage and comorbidities such as diabetes and hypertension remains unclear.[19,20] In light of all these links, comorbidities of the patients seem to have a significant impact on surgical delay and PBT.
The relationship between urolithiasis and endothelial dysfunction has been demonstrated in various animal experiments and clinical studies. Long-term exposure to stones in the kidney may increase inflammation and consequently oxidative stress factors in the urinary system. Oxidative stress leads to an increase in pro-inflammatory cytokines in the region that may damage kidney glomeruli, tubules, and vessels. As a result, inflammation and fibrosis occur that may negatively affect kidney functions.[21] In our study, the increased rate of PBT due to prolonged TDT can be explained by this inflammatory process occurring in the renal vessels.
The main strength of this study is that it is the first study to investigate the effects of prolonged TDT on surgical outcomes in patients undergoing PNL. The main limitations include its single-center, retrospective design with a heterogeneous sample. In addition, we were unable to compare the PNL cases based on the individual experience (annual case number) of each surgeon.
Conclusion
Our study results indicate a positive, significant correlation between TDT and PBT in PNL patients. In addition, the need for PBT increases in patients undergoing PNL longer than 90.5 days after the diagnosis. However, further large-scale, prospective studies are warranted to gain a better understanding of the exact timing of PNL and to reduce the need for blood transfusion in this patient population.
Footnotes
Please cite this article as ”Sahin Y, Yilmaz M, Kilic E, Muslumanoglu AY. Surgical Delay Increases the Perioperative Blood Transfusion Rate In Percutaneous Nephrolithotomy. Med Bull Sisli Etfal Hosp 2023;57(3):–1”.
Disclosures
Ethics Committee Approval
The study was approved by the Ethics Committee of Istanbul Medipol University Non-invasive Clinical Research (No: 513, dated 20.05.2021).
Patient informed consent
All patients were informed about the nature of the procedure and a written informed consent was obtained.
Peer-review
Externally peer-reviewed.
Conflict of Interest
None declared.
Authorship Contributions
Concept – Y.S., M.Y., E.K., A.Y.M.; Design – Y.S., M.Y., E.K., A.Y.M.; Supervision – Y.S., M.Y., E.K., A.Y.M.; Data collection and/or processing – Y.S., M.Y., E.K.; Analysis and/or interpretation – Y.S., M.Y., A.Y.M.; Literature review – Y.S., M.Y.; Writing – Y.S., M.Y., E.K.; Critical review – Y.S., M.Y., A.Y.M.
References
- 1.ßSorokin I, Mamoulakis C, Miyazawa K, Rodgers A, Talati J, Lotan Y. Epidemiology of stone disease across the world. World J Urol. 2017;35:1301–20. doi: 10.1007/s00345-017-2008-6. [DOI] [PubMed] [Google Scholar]
- 2.Zhe M, Hang Z. Nephrolithiasis as a risk factor of chronic kidney disease: a meta-analysis of cohort studies with 4,770,691 participants. Urolithiasis. 2017;45:441–8. doi: 10.1007/s00240-016-0938-x. [DOI] [PubMed] [Google Scholar]
- 3.Smith A, Averch TD, Shahrour K, Opondo D, Daels FP, Labate G, et al. CROES PCNL Study Group. A nephrolithometric nomogram to predict treatment success of percutaneous nephrolithotomy. J Urol. 2013;190:149–56. doi: 10.1016/j.juro.2013.01.047. [DOI] [PubMed] [Google Scholar]
- 4.Okhunov Z, Friedlander JI, George AK, Duty BD, Moreira DM, Srinivasan AK, et al. S.T.O.N.E. nephrolithometry: novel surgical classification system for kidney calculi. Urology. 2013;81:1154–9. doi: 10.1016/j.urology.2012.10.083. [DOI] [PubMed] [Google Scholar]
- 5.de la Rosette J, Assimos D, Desai M, Gutierrez J, Lingeman J, Scarpa R, et al. CROES PCNL Study Group The Clinical Research Office of the Endourological Society Percutaneous Nephrolithotomy Global Study: indications, complications and outcomes in 5803 patients. J Endourol. 2011;25:11–7. doi: 10.1089/end.2010.0424. [DOI] [PubMed] [Google Scholar]
- 6.Eksi M, Ozlu DN, Kargi T, Yavuzsan AH, Haciislamoglu A, Karadag S, et al. Pre-operative parameters predicting hemoglobin decline related to percutaneous nephrolithotomy. Sisli Etfal Hastan Tip Bul. 2022;56:70–6. doi: 10.14744/SEMB.2021.21284. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Proietti S, Gaboardi F, Giusti G. Endourological stone management in the era of the COVID-19. Eur Urol. 2020;78:131–3. doi: 10.1016/j.eururo.2020.03.042. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Neal RD, Tharmanathan P, France B, Din NU, Cotton S, Fallon-Ferguson J, et al. Is increased time to diagnosis and treatment in symptomatic cancer associated with poorer outcomes? Systematic review. Br J Cancer. 2015;112(Suppl 1):S92–107. doi: 10.1038/bjc.2015.48. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Tsai WC, Kung PT, Wang YH, Kuo WY, Li YH. Influence of the time interval from diagnosis to treatment on survival for early-stage liver cancer. PLoS One. 2018;13:e0199532. doi: 10.1371/journal.pone.0199532. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Yamaguchi A, Skolarikos A, Buchholz NP, Chomón GB, Grasso M, Saba P, et al. Clinical Research Office Of The Endourological Society Percutaneous Nephrolithotomy Study Group Operating times and bleeding complications in percutaneous nephrolithotomy: a comparison of tract dilation methods in 5,537 patients in the Clinical Research Office of the Endourological Society Percutaneous Nephrolithotomy Global Study. J Endourol. 2011;25:933–9. doi: 10.1089/end.2010.0606. [DOI] [PubMed] [Google Scholar]
- 11.Akman T, Binbay M, Sari E, Yuruk E, Tepeler A, Akcay M, et al. Factors affecting bleeding during percutaneous nephrolithotomy: single surgeon experience. J Endourol. 2011;25:327–33. doi: 10.1089/end.2010.0302. [DOI] [PubMed] [Google Scholar]
- 12.Srivastava A, Singh KJ, Suri A, Dubey D, Kumar A, Kapoor R, et al. Vascular complications after percutaneous nephrolithotomy: are there any predictive factors? Urology. 2005;66:38–40. doi: 10.1016/j.urology.2005.02.010. [DOI] [PubMed] [Google Scholar]
- 13.Paick SH, Park HK, Oh SJ, Kim HH. Characteristics of bacterial colonization and urinary tract infection after indwelling of double-J ureteral stent. Urology. 2003;62:214–7. doi: 10.1016/S0090-4295(03)00325-X. [DOI] [PubMed] [Google Scholar]
- 14.Abdelaziz AY, Fouda WB, Mosharafa AA, Abelrasoul MA, Fayyad A, Fawzi K. Forgotten ureteral stents: Risk factors, complications and management. African J Urol. 2018;24:28–33. doi: 10.1016/j.afju.2017.09.005. [DOI] [Google Scholar]
- 15.Ray RP, Mahapatra RS, Mondal PP, Pal DK. Long-term complications of JJ stent and its management: a 5 years review. Urol Ann. 2015;7:41–5. doi: 10.4103/0974-7796.148599. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Assad A, Nguyen DD, Sadri I, Bhojani N. The impact of delaying acute kidney stone surgery on outcomes. Can Urol Assoc J. 2021;15:E418–22. doi: 10.5489/cuaj.6877. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Bjazevic J, Nott L, Violette PD, Tailly T, Dion M, Denstedt JD, et al. The evolution of percutaneous nephrolithotomy: analysis of a single institution experience over 25 years. Can Urol Assoc J. 2019;13:E317–24. doi: 10.5489/cuaj.5725. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Ginsburg KB, Curtis GL, Patel DN, Chen WM, Strother MC, Kutikov A, et al. Association of surgical delay and overall survival in patients with T2 renal masses: implications for critical clinical decision-making during the COVID-19 pandemic. Urology. 2021;147:50–6. doi: 10.1016/j.urology.2020.09.010. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Li Z, Wu A, Liu J, Huang S, Chen G, Wu Y, et al. Risk factors for hemorrhage requiring embolization after percutaneous nephrolithotomy: a meta-analysis. Transl Androl Urol. 2020;9:210–7. doi: 10.21037/tau.2020.01.10. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Zhao H, Li J, Li L, Wang H, Guo J, Miao Y. Factors affecting transfusion during percutaneous nephrolithotomy: a retrospective study of 665 cases. Appl Bionics Biomech. 2022;2022:6775277. doi: 10.1155/2022/6775277. [DOI] [PMC free article] [PubMed] [Google Scholar] [Retracted]
- 21.Saenz-Medina J, Muñoz M, Rodriguez C, Sanchez A, Contreras C, Carballido-Rodríguez J, et al. Endothelial dysfunction: an intermediate clinical feature between urolithiasis and cardiovascular diseases. Int J Mol Sci. 2022;23:912. doi: 10.3390/ijms23020912. [DOI] [PMC free article] [PubMed] [Google Scholar]