Early Prediction Of Recurrent Ureteropelvic Junction Obstruction After Unilateral Pyeloplasty In Children

BackgroundCongenital hydronephrosis is the most common urinary malformation in children.The most common cause is ureteropelvic junction obstruction(UPJO).Some children with hydronephrosis can relieve themselves after birth,while others have a continuous obstruction of urine outflow,which leads to the expansion of the renal collection system.If they are not treated in time,the pressure in the collection system continues to increase,resulting in irreversible damage to renal function.Anderson-Hynes dismembered pyeloplasty is the gold standard for the treatment of UPJO.The success rate reported in the literature for many years is more than 90%,but there are still some patients with recurrent ureteropelvic junction obstruction.Therefore,regular follow-up is needed after pyeloplasty to monitor the recovery of renal function and morphology,and to detect patients with re-obstruction as early as possible to avoid further decline of renal function.At present,the strategy of postoperative follow-up has not been agreed at home and abroad.Ultrasound and diuretic radionuclide renogram are commonly used in postoperative follow-up,but diuretic radionuclide renogram is invasive,radioactive,expensive,and the results are affected by many factors,so it is not the first choice for long-term follow-up.While ultrasound is non-radiation,low price,safe and reusable,which plays an important role in postoperative follow-up.In recent years,studies have shown that some ultrasonic parameters such as the ratio of anteroposterior diameter of renal pelvis to the thickness of the renal cortex or renal parenchyma and the percentage of improvement of the anteroposterior diameter of the renal pelvis(PI-APD)can be used as objective indicators for follow-up after pyeloplasty.However,some of the above studies only suggest that the indexes have obvious changes after operation,and the relationship between them and the outcome of the operation has not been further discussed;some follow-up time is too short,and the sample size is too small.Therefore,in this study,the children who underwent unilateral pyeloplasty were followed up for 2 to 5 years to observe the relationship between ultrasound index of anterior and posterior diameter of renal pelvis/renal parenchyma thickness(APD/PT),PI-APD in the early stage after pyeloplasty,and to explore whether they can predict the occurrence of recurrent ureteropelvic junction obstruction after pyeloplasty.ObjectiveTo analyze the changes of renal ultrasound indexes after pyeloplasty,to explore the predictive ability of APD/PT value and PI-APD value 3 months after pyeloplasty to the occurrence of recurrent ureteropelvic junction obstruction after pyeloplasty,and to determine the best critical value for prediction.MethodsThe clinical data of children who underwent unilateral pyeloplasty in the Department of Urology of the third affiliated Hospital of Zhengzhou University from January 2013 to December 2017 were collected.The operative age,sex,affected side,degree of preoperative hydronephrosis,anteroposterior diameter of the renal pelvis and parenchymal thickness before and after operation,APD/PT value and PI-APD value after operation were recorded.According to the occurrence of recurrent ureteropelvic junction obstruction after operation,they were divided into re-obstruction group and non-obstruction group.Wilcoxon signed rank test was used to compare the changes of renal ultrasound indexes before and after operation.The clinical data of the two groups were analyzed by univariate analysis,and the relationship between APD/PT value and PI-APD value 3 months after operation was analyzed by Spearman test,and the meaningful indexes were analyzed by binary Logistic multivariate regression analysis.Draw the ROC curve and determine the best critical point according to the area under the curve.The test level was a=0.05.ResultsA total of 201 cases were included,including 142 males,59 females,123 cases on the left side and 78 cases on the right side.There were 110 cases of SFU3 grade and 91 cases of SFU4 grade before operation.During the follow-up of 2 to 5 years,the changes of ultrasonic indexes such as anterior and posterior diameter of renal pelvis,thickness of renal parenchyma and APD/PT value were significantly different from those before operation(P<0.01),and the amplitude of changes after 6 months operation decreased.10 cases(5.0%)developed re-obstruction,the average age of the first operation was 3.64±3.16 months,191 cases(95.0%)had no re-obstruction,and the average age of the first operation was 5.86±9.93 months.There was no significant difference in the age,sex and side of the operation between the two groups(P=0.277,0.484,0.743),but there was significant difference in the degree of hydronephrosis before operation between the two groups(P<0.05),and there was no significant difference in the age,sex and side of the operation between the two groups(P>0.05).Three months after pyeloplasty,the APD/PT value and PI-APD value in the re-obstruction group were 13.90±0.32 and 20.68%±4.53%respectively,while those in the non-obstruction group were 8.12±2.80 and 40.11%±12.63%,respectively,and the difference was statistically significant(P<0.01).There was a strong negative correlation between APD/PT value and PI-APD value 3 months after pyeloplasty(r=-0.569,P<0.01).The results of binary Logistic multivariate analysis showed that the values of APD/PT and PI-APD at 3 months after pyeloplasty could predict the occurrence of recurrent obstruction after pyeloplasty(P=0.027,0.005).The area under the ROC curve of the APD/PT value is 0.980(P<0.01,95%CI:0.936?0.997),the optimal critical value is 13.3,the sensitivity is 100%,the specificity is 96.52%,and the area under the ROC curveof the PI-APD value is 0.941(P<0.01,95%CI:0.882?0.976),the best critical value is 27.2%,the sensitivity is 100%,and the specificity is 87.83%.ConclusionFor children who underwent pyeloplasty for the first time,APD/PT value and PI-APD value 3 months after operation have higher predictive value for the occurrence of postoperative reobstruction,and the best critical values predicted are 13.3%and 27.2%respectively.And the higher APD/PT value and the lower PI-APD value suggest that the risk of reoccurrence is higher.