| Background Neurogenic Lower Urinary Tract Dysfunction(NLUTD)is lower urinary tract dysfunction secondary to confirmed pathology of the nervous supply.It is one of the most challenging problems in urology.Patients with NLUTD have a variety of long-term complications,including kidney failure,urinary incontinence,urinary tract infections,urinary tract stones,and bladder tumors.Renal failure caused by upper urinary tract damage(UTD)is the main cause of death in patients with NLUTD caused by congenital neurodevelopment or acquired nerve injury [1].Early identification and treatment of UTD risk factors can effectively reduce the incidence of renal failure.At present,urodynamic examination is the only one method that can objectively evaluate lower urinary tract function[2].However,urodynamic examination is an invasive,complicated,expensive,and easy to cause iatrogenic infection.UTD monitoring methods also include cystography,renal dynamic imaging and so on.Because NLUTD patients require long-term follow-up,these monitoring methods are complex and radioactive,limiting the use of these methods.Ultrasonic measurement of bladder wall thickness(BWT)or detrusor wall thickness(DWT)as a non-invasive examination has received increasing attention in recent years.There are many studies on ultrasound measurement of BWT.There have been several reports in the literature that BWT is closely associated with male bladder outlet obstruction[3-5].BWT thickening is also closely associated with female detrusor overactivity(DO),pediatric urethral valve disease,and bladder outlet obstruction,detrusor-sphincter-dyssynergia(DSD)and low compliance bladder[6-8].It has also been confirmed in animal experiments that BWT thickening is associated with bladder outlet obstruction[9].The increase in BWT is through tissue hypoxia and denervation,which results in smooth muscle hypertrophy and thickening of connective tissue.Over time,bladder compliance decreases.Histologically it has also been demonstrated that detrusor hypertrophy and fibrin deposition can be seen on the thickened bladder wall [10].Abnormal bladder metabolism can also lead to an irreversible increase in the weight of the bladder wall or bladder.In animal studies of lower urinary tract obstruction,bladder weight increases and BWT thickens due to smooth muscle hypertrophy and deposition of connective tissue[11].Studies on patients have found that due to nerve damage leading to decreased innervation,hypoxia,and connective tissue deposition may cause bladder smooth muscle hypertrophy and decreased bladder compliance,resulting in increased bladder detrusor thickness[12].The neurogenic bladder animal model also showed histological pathology with increased bladder weight and increased bladder wall thickness [13,14].It can be speculated that BWT or DWT can reflect the workload of the bladder,which is similar to cardiac hypertrophy caused by increased cardiac load in hypertensive patients [15].Therefore,it is possible that the bladder wall thickness can be used to assess the presence of UTD in patients with NLUTD,thus avoiding invasive,expensive,and time-consuming urodynamic examinations in patients with NLUTD.The correlation between ultrasound measurement BWT and UTD in adult NLUTD patients has not been reported at internal and abroad.This study retrospectively analyzed the clinical data of NLTUD patients hospitalized in the Department of Urology at the First People’s Hospital of Guangzhou from January 2013 to October2017.The correlation between BWT and urodynamic parameters in patients with NLUTD was analyzed to assess the relationship between BWT and UTD,and explore the value of BWT to predict UTD.Objective By analyzing the correlation between BWT,urodynamic parameters and UTD in patients with NLUTD,the value of BWT in predicting UTD was explored.Methods Retrospectively analyzed the clinical data of 263 NLUTD patients hospitalized in the Department of Urology,First People’s Hospital of Guangzhou from January2013 to October 2017.Inclusion criteria:(1)Age ≥ 18 years old;(2)History of previous spinal cord injury or other neuropathy ≥ 1 year;(3)Patients with lower urinary tract symptoms and clinical diagnosis of NLUTD;(4)There were urological ultrasound examination results;(5)There were inspection results that could identify the UTD indicator.Exclusion criteria:(1)Bladder stones;(2)Acute urinary tract infections;(3)history of lower urinary tract surgery;(4)history of pelvic tumor radiotherapy;(5)Long-term indwelling catheter or cystostomy tube.UTD diagnostic criteria: one of the following criteria [16].(1)SCr> 123 μmol/L(according to the standards of the laboratory of our hospital);(2)ultrasonography or IVU suggests the presence of renal or ureteral dilatation(diameter of the renal collecting system> 10 mm,ureteral dilation> 5 mm);(3)Unilateral glomerular filtration rate <90m L/min/1.73m2;(4)Bladder angiography confirmed vesicoureteral reflux.The patients with UTD were divided into experimental group,and those without UTD into control group.The differences in BWT and urodynamic parameters between the experimental and control groups were compared.The ROC curve was used to determine the critical value of BWT in the diagnosis of UTD,and the correlation between BWT and UTD and urodynamic parameters was analyzed.Results From January 2013 to October 2017,a total of 263 NLTUD patients were hospitalized in the Department of Urology,Guangzhou First People’s Hospital.161 cases were included in the study,including 92 males and 69 females.Age 39.5±18.4(18-81)years old.There were 89 cases of renal or ureteral hydronephrosis.Ureteral bladder reflux in 14 cases.In 30 cases,serum creatinine(SCr)increased,with a SCr of(290.7±164.0)μmol/L and range of 125 to 938μmol/L.In 17 cases,the unilateral GFR decreased,with a GFR of(45.2±23.0)ml/(min·1.73 m2)and a range of 84.3 to 14.6ml/(min·1.73 m2).According to the presence or absence of UTD,it was divided into experimental group and control group: 101 cases in the experimental group(with UTD)and 60 cases in the control group(without UTD).In the experimental group,there were 60 males and 41 females;the age was(37.9±19.1)years;there were 83 cases with hydronephrosis or ureteral hydronephrosis,14 cases with vesicoureteral reflux,30 cases with increased SCr,and 17 cases with decreased GFR.There were 60 patients in the control group,32 males and 28 females;aged(42.3±16.8)years.There was no significant difference between the two groups in gender proportion and age(P>0.05).In this study,all 161 patients underwent ultrasonography to measure BWT.119 underwent urodynamic examinations.BWT of 161 cases was 2 to 25 mm with a median value of 7.0(7.1)mm.The results of urodynamic examination showed that the bladder compliance was 0.8 to 141.5 ml/cm H2 O with a median value of 12.7(22.8)ml/cm H2 O,and the maximum bladder pressure capacity(MCC)was 49 to 700 ml,with a median value of 256(171)ml;The maximum detrusor pressure during filling(Pdet.max)was 3 to 144 cm H2O(1 cm H2O=0.098 k Pa)with a median value of 34(19.1)cm H2 O.The BWT median values of the experimental and control groups were9.0(5.0)mm and 4.0(5.7)mm,respectively,and the medians of bladder compliance was 9.3(15.3)ml/cm H2 O and 24.2(38.7)ml/cm H2 O,respectively.The medians of MCC were 225.0(159.0)ml and 310.6(140.5)ml,respectively,and the median values of Pdet.max were 40.0(20.4)cm H2 O and 29.2(18.4)cm H2 O,respectively.The differences were statistically significant(Z=-5.931,P< 0.001;Z=-4.07,P<0.05;Z=-2.22,P<0.05;Z=-2.92,P<0.05).Multivariate correlation analysis showed that BWT was negatively correlated with bladder compliance and MMC(r=-0.419,P<0.001;r=-0.198,P=0.031)and positively correlated with Pdet.max(r=0.251,P =0.006).According to the ROC curve,the critical value of BWT was determined to be4.8 mm,and the sensitivity and specificity for predicting UTD were 86.1% and 53.3%,individualy.Conclusions1.Thickening of BWT is one of the risk factors for UTD in patients with NLUTD;2.When BWT ≥ 4.8mm,NLUTD patients are more likely to have UTD,which can be used as an examination method for the diagnosis of UTD in NLUTD patients. |
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