A Prediction Model For Risk Factors Of Testicular Atrophy After Orchiopexy In Children With Undescended Testis

Objective:Undescended testis is a common disease in male children,and the first choice of treatment is orchiopexy.Testicular atrophy is a severe complication after orchiopexy,but there have been limited studies with small sample sizes about risk factors of testicular atrophy.Thus,we aimed to investigate the risk factors for testicular atrophy after orchiopexy in male children with undescended testes and develop a prediction model based on clinical variables.Materials and Methods:We performed a retrospective review of data on children who underwent orchiopexy for undescended testes from 2013 to 2017.The inclusion criteria were as follows:1)Patients were under 14 years old,2)complete patient records were available,and 3)they underwent orchiopexy with a preoperative ultrasound test,were followed up for more than 1 year with an ultrasound scan.The exclusion criteria were as follows:1)patients with disorders of sex development or abnormal chromosomes,2)incomplete patient data,and 3)testicular nubbin or remnants removed at the time of surgical exploration.The variables assessed included age,laterality,testicular location,preoperative testicular volume,deferens and epididymis anomaly,hormonal treatment,comorbidities,type of surgical procedure,operating time,and intraoperative complications.TA was defined as a reduction of>50%of the TV compared to the contralateral,normally descended testis.Univariate analysis and multiple logistic regression analysis were performed to analyze the independent risk factors predicting TA,and a nomogram was constructed to predict the probability of TA.We also validated our model based on a prospective cohort of patients who underwent orchiopexy from January 2018 to December 2018.In order to make the definition of testicular atrophy precisely,we retrospectively studied the male children with normal testes who underwent testicular ultrasound between January 2016 and June 2019,and we measured the testicular volume includes the mean value,standard deviation and median.Results:A total of 1608 patients undergoing orchiopexy were included in the training cohort.The median age was 2.8 years(range,0.5-11.3 years).We recorded low UDT in 373 cases,middle UDT in 1041 cases,and high UDT in 194 cases.Totally 228(14.2%)cases of atrophic testes were recorded.By multiple logistic regression analysis,the independent predictors of testicular atrophy were preoperative testicular volume ratio(odds ratio(OR)0.001,p=0.001),testicular location(OR 1.903,p=0.001),deferens and epididymis anomaly(OR 6.470,p=0.001),and two-stage Fowler-Stephens orchiopexy(OR 2.613,p=0.04).No significant differences were observed with respect to other variables.We constructed a prediction model and a nomogram using these risk factors to predict the probability of testicular atrophy.Successful validation was achieved,and a receiver operating characteristic(ROC)curve was constructed.The sensitivity and specificity of the prediction model were 78.1%and 77.5%,respectively.The area under the ROC curve was 0.851.There were totally 1607 children with normal testes.We measured both testes,and calculate the mean value,standard deviation and median.The testicular volumes grew slowly before 8 years old(0.372-0.678ml),while they grew fast after 9 years old(1.040～4.600ml).Conclusions:The incidence of testicular atrophy after orchiopexy is higher in patients with a lower testicular volume ratio,higher testicular location,deferens and epididymis anomaly,and in two-stage Fowler-Stephens orchiopexy.Therefore,this prediction model provides useful evidence for surgeons to choose an appropriate surgical procedure for undescended testes and predict the probability of testicular atrophy.