| Background: Renal stones are the most common diseases of the urologic system.At present,the most commonly used techniques for the treatment of kidney stones include extracorporeal shock lithotripsy(ESWL),percutaneous nephrolithotomy(PCNL),and ureteroscopy lithotripsy(URS and FURS).Before deciding on the surgical technique,the patients' health conditions,accompanying diseases,renal functions,the degree of obstruction,stones characteristics such as size,location,and numbers should be considered.Although there are many factors such as stone load and surface area,which are used to assess the surgical risk of kidney stones,the incidence of complications and the rate of stone clearing,but at the beginning of PCNL and FURS there was no simple and effective method to predict the complexity of the stones and the rate of stone clearing before the stone removal operation.The S.T.O.N.E.is a new scoring system that is used to predict PCNL outcomes;it allows surgeons to make an accurate assessment of stones free rates(SFR).Several studies reported that the S.T.O.N.E scoring system can effectively predict the postoperative stone clearance status of PCNL.Guy 's stone score classification method predicts the SFR according to the stone locations,number and renal dissection.Smith et al,designed a new scoring system for predicting renal stones free rate,called: Clinical Research Office of the Endourological Society(CROES),the scoring system variables including stone burden,quantity,position,the existence of the staghorn stone,the number of cases treated each year.The modified Clavien system allow us to classify the complications of Perioperative and postoperative.Regardless of the choice of technique for surgical treatment of renal stones,improving the rate of stone clearance and reducing the incidence of postoperative complications are the most important objectives.PCNL or FURS postoperative residual stones may cause harm to patients;it is the main reason for postoperative acute obstruction and acute infection.Residual stones may increase and lead to recurrence.Repeated recurrence of stones leads to renal insufficiency or even kidney failure.Thus,predicting postoperative stone clearance rate and exploring the factors that may affect the SFR and complications help in the selection of the appropriate surgical method.Objectives: This study aimed to compare the outcomes of percutaneous nephrolithotomy(PCNL)and flexible ureteroscopy(FURS)for renal stones and to assess what the renal stone score systems are useful for the treatment decision choices.Material and methods: We retrospectively examined patients with renal stones who were eligible for both PCNL and FURS and underwent PCNL or FURS.Preoperative abdominopelvic computerized tomography images(CT)of these patients were reviewed and scored according to the scoring systems and classified as follows: 1-S.T.O.N.E scoring system: patients classified into three groups,low complex,moderate complex,and high complex.2-CROES scoring system: into four groups,Grade 1,Grade 2,Grade3,Grade 4.3-Guy scoring system: into four groups G I,G II,G III,G IV.The postoperative stone-free status,complications incidence rate & types(classified according to the Clavein Dindo classification)and number of procedures between the PCNL and FURS were compared independently in each score system.Univariate analyses were conducted to determine the related score system parameters and predictive factors that affect stone free rates(SFRs)and complication rates.Results: Out of 301 patients,210 were treated by PCNL and 91 were treated by FURS.According to S.T.O.N.E score system,the SFRs for PCNL and FURS in the low,moderate,and high complexity stones groups were: 92.3% vs 88.9%(p=1.000),90% vs71.8%(p=0.002),and 72.2% vs 27.3%(p=0.007),respectively.The complication rates for PCNL and FURS in the three groups were 7.7% vs 22.2%(p=0.544),15% vs 7%(p=0.111),and 15.5% vs 27.3%(p=0.388),respectively.There were significant differences in SFR between the two techniques in Stone size,Obstruction,and Number of calyces of S.T.O.N.E variable.Whereas the Essence(HU)was the only parameter of S.T.O.N.E score showed different significant in terms of complications.According to the CROES scoring system,the SFR for PCNL and FURS in the four groups were: 60% vs 25%(p = 0.559),60% vs 27.3%(p = 0.058),81.9% vs 68.1%(p = 0.065),95.8 vs 89.7%(p = 0.0352)respectively.The difference in SFR between the four groups was statistically significant(p = 0.008).The complication rates of PCNL and FURS in each group were 30.0%% vs 25.0%,25.7% vs 18.2,14.9% vs 14.9%,7.0%vs 0.0% respectively.For the incidence of complications,there was no statistically significant difference between the two operation methods in each group and between the four groups(p >0.05).Guy's scoring system G I,G II,G III,G IV,the SFR for PCNL and FURS were 97.3% vs75.8%,83.5 vs 68.0%,75.6% vs 20.0%,57.9% vs 66.7 respectively.Differences of SFR between the two techniques in G I,G II and G III were statistically significant P < 0.05.There was no significant difference in postoperative complications between PCNL group and FURS group.Univariate analysis also revealed that SFRs in patients treated by PCNL or FURS were affected by previous surgery(p < 0.05).Whereas body mass index(BMI),renal dysfunction,and operation time were only significant in PCNL.According to the classification of S.T.O.N.E scoring system,the occurrence rate of secondary operation of PCNL group in the middle and high complexity stones group was higher than in the FURS group,the difference was statistically significant(p <0.05).Conclusions: Three stone scoring systems were significantly correlated with postoperative stones clearing rate.Categorizing patients with renal stones who are eligible for PCNL and FURS according to the S.T.O.N.E.' and Guy's scoring system was useful for predicting the postoperative stone-free status and for choosing the appropriate surgical technique.The efficacy of PCNL groups were higher in the treatment of moderate and high complexity groups than in the FURS groups. |
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