Feasibility study of modified RUSS to predict the stone free rate after flexible ureteroscopic lithotripsy / 中华泌尿外科杂志

ABSTRACT

Objective To explore the feasibility of the modified RUSS (Resorlu-Unsal Stone Score)renal stone scoring system in predicting the stone free rate after Flexible Ureteroscopic Lithotripsy(FURL).Methods Retrospective analysis was performed on 104 cases of renal stones treated by FURL from March 2017 to January 2019 in the second affiliated hospital of zhengzhou university,including 75 males and 29 females.Age 20-75 (47.79 ± 13.21) years.BMI 18.2-38.3 (24.4 ± 3.7) kg/m2;Crushed stone siteleft 56 cases,right 48 cases.There were 23 cases of renal inferior calyces calculi,81 cases of non-inferior calyces calculi,and 19 cases of renal inferior calyces calculi with IPA ＜ 45°;American Society of Anesthesiology (ASA) scores65 cases of grade Ⅰ,39 cases of grade Ⅱ;There were 71 patients with urinary tract infection before operation.There were 6 cases of renal puncture fistula before operation.Preoperative indwelling ureteral stent in 26 cases;There were 32 cases with history of extracorporeal shock wave lithotripsy.There were 27 patients with a history of urolithiasis therapy.The same physician used preoperative urinary CT + 3D reconstruction imaging data to measure the factors influencing the postoperative stone free rate.RUSS renal stone scoring system was used to score the stones of patients before operation,and the relationship between the scores and the stones free rate was analyzed.The RUSS renal stone scoring system was supplemented and improved by including staghorn stone,duplicate renal,caliceal diverticulum,renal malrotation,stone area,and CT value related indexes.The modified RUSS renal stone scoring system was used to score the preoperative stone condition of patients,and the relationship between the score and the stone free rate was analyzed.The receiver operating characteristic curve (ROC) was drawn and the area under the curve (AUC) was calculated to compare the advantages and disadvantages of the modified RUSS,the characteristics of the stones,and RUSS system.Results The stone free rate was 69.2％ (72/104) 4 weeks after the operation,and there were no postoperative complications.Single-factor analysis showed that stone area,CT value,number of renal calyx involved by stone,multiple stones,IPA,stone size grading,renal anatomic structure abnormality,staghorn stone were all related risk factors affecting postoperative patients.Multi-factor analysis showed that stone area,number of renal calyces involved by stone,multiple stones,IPA and stone size were independent risk factors affecting the stone free rate after FURL.RUSS scores ranged from 0 to 3 points,corresponding to stone clearing rates of 86.8％ (33/38),67.7％ (23/34),58.3％ (14/24) and 25.0％ (2/8),respectively.Stone clearing rates were significantly correlated with stone grading (P ＜ 0.05).The total scores of stone free group and residual stone group were (0.87 ± 0.96) points and (1.53 ± 0.98) points,respectively,with significant differences between the groups (P ＜ 0.05).The range of modified RUSS score was 0-4 points,corresponding to the stone clearing rate of 100.0％ (25/25),92.3％ (24/26),54.2％ (13/24),47.4％ (9/19),and 10.0％ (1/10),respectively.Stone free rate was significantly correlated with stone grading (P ＜ 0.05).The total scores of stone free group and residual stone group were (1.15 ± 1.13) points and (2.81 ± 0.93) points,respectively,with significant differences between the groups (P ＜ 0.05).The AUC of stone features was smaller than that of the modified RUSS scoring system.The AUC of RUSS scoring system (0.707,95 ％ CI 0.598-0.815) was smaller than that of the modified RUSS scoring system (0.865,95％ CI 0.797-0.933).Conclusions Both the RUSS scoring system and the modified RUSS scoring system could accurately predict the postoperative stone free status of FURL,while the modified RUSS scoring was more accurate than the RUSS scoring.