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 Table of Contents  
ORIGINAL ARTICLE
Year : 2021  |  Volume : 54  |  Issue : 1  |  Page : 7-10

Postablation and α-1 blocker therapy in children with congenital obstructing posterior urethral membrane


1 Department of Pediatric Surgery AIIMS, New Delhi, India
2 Department of Trauma, Apex Trauma Centre Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

Date of Submission18-Jun-2020
Date of Decision20-Jul-2020
Date of Acceptance17-Aug-2020
Date of Web Publication22-Jan-2021

Correspondence Address:
Amit Kumar Singh
Department of Trauma Surgery, Apex Trauma Centre, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow - 226 014, Uttar Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/fjs.fjs_97_20

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  Abstract 


Background: Congenital obstructing posterior urethral membrane (COPUM) or posterior urethral valve (PUV) is the most common cause of lower urinary tract obstruction in boys. Approximately one-third of boys with PUV develop end-stage renal disease. Various prognostic factors have been recognized which determines the long-term outcome of these cases.
Materials and Methods: This was a retrospective case–control analysis of data from January 1998 to May 2014. All patients of COPUM with radiological evidence of bladder neck hypertrophy with follow-up of 7 years were included in the study. Patients with urethral strictures, neurogenic bladder, and incomplete records were excluded. Group I (n = 57) received selective α-1 blocker (prazosin), after valve ablation. Group II (n = 36) who had not received the α-1 blocker was treated as a control group. Investigations include renal function test, ultrasonography, micturating cystourethrography renal dynamic scan, and glomerular filtration rate. Statistical analysis was done using the paired t-test, multiple serial analyses using ANOVA. P <0.05 was considered as significant.
Results: A total of 113 patients of COPUM were treated from January 1998 to May 2014. Out of these 113, 93 patients (82.3%) were included in the study. Fifty-seven (61.2%) received α-1 blocker, while 36 patients (38.8%) acted as control. Significant decrease in bladder neck hypertrophy noted in Group I as compared to Group II (P<0.001).
Conclusion: Uses of alpha-1 blocker hastens the recovery in terms of clinical improvement, resolution of bladder neck hypertrophy, and improved peak urine flow rate.

Keywords: Alpha-1 blocker, anticholinergic, congenital obstructing posterior urethral membrane, posterior urethral valve


How to cite this article:
Bajpai M, Baba A, Singh AK. Postablation and α-1 blocker therapy in children with congenital obstructing posterior urethral membrane. Formos J Surg 2021;54:7-10

How to cite this URL:
Bajpai M, Baba A, Singh AK. Postablation and α-1 blocker therapy in children with congenital obstructing posterior urethral membrane. Formos J Surg [serial online] 2021 [cited 2021 Mar 6];54:7-10. Available from: https://www.e-fjs.org/text.asp?2021/54/1/7/307628




  Introduction Top


Congenital obstructing posterior urethral membrane (COPUM) is the most common cause of obstructive uropathy, which leads to renal failure in childhood.[1] COPUM represents a disease spectrum with varying severity and has profound effects on the bladder as well as the upper tracts. The incidence of end stage renal disease in COPUM patients varies from 24% to 33% depending on the duration of follow-up.[2],[3] Various prognostic factors have been recognized which determines the long-term outcome of these cases. These factors include serum creatinine at the age of 1 year, urinary incontinence, in utero presentation, sonographic appearance of renal pyramids, presence of reflux, presence of Popoff mechanism, and plasma renin activity.[4],[5],[6],[7] Bladder dysfunction has been recently recognized as one of the most important factors for the long-term outcome in these cases.[8] Children with COPUM develop detrusor fibrosis results in decreased compliance and instability, leading to poor emptying and recurrent urinary tract infections.[9] This bladder dysfunction contributes to the long-term morbidity despite adequate relief of obstruction due to the membranes. α-1 blockers which are primarily used in adults suffering from benign prostatic hyperplasia have gained acceptance in children as well, to reduce the obstruction at the level of the bladder neck region. As very limited studies have been carried out so far to demonstrate the role of α-1 blocker in patients with COPUM, we conducted this study.[10],[11]

Aim and objective

To evaluate the clinical improvement and radiological and urodynamic changes after use of α-1 blockers in children of COPUM.


  Materials and Methods Top


This was a retrospective case–control analysis of data from January 1998 to May 2014. Ethical clearance was taken for the study from the institutional ethics committee. (Vide letter no. AIIMS/BE/612/2016 dated 29 Nov 2016). Informed written consent was obtained from the patients. Inclusion criteria were all patients of COPUM with radiological evidence of bladder neck hypertrophy and minimal follow-up of 7 years. Exclusion criteria were patients with urethral strictures, neurogenic bladder, and incomplete records. All these patients were managed according to the step ladder protocol developed and reported previously by the senior author. This involve direct valve incision with the cold knife in stable patients, while initial catheterization was done in unstable patients followed by valve incision. Those patients who remained unstable despite catheterization were subjected to high diversion as bilateral ureterostomies after 48 hours of catheterization. Vesicostomy was made in those patients where small cystoscopes were not available for valve incision.[12] A total of 113 patients of COPUM were followed up in our urology clinic. Out of these 113, 93 patients (82.3%) satisfying the inclusion criteria were included in the study. Group I (n = 57) was treated with a selective α-1 blocker (prazosin), after valve ablation. Prazosin was started at a dose of 20 mcg/kg/day increasing up to 50 mcg/kg/day over 1 week. Group II (n = 36) who had not received α-1 blocker was treated as a control group. Cases were followed up with micturating cystourethrogram (MCU) done at 6 weeks, 6 months, and at 1-year postablation. Bladder neck hypertrophy was defined as lucent ring or collar between the bladder neck and posterior urethra seen in an oblique film in MCU. Bladder neck hypertrophy was measured objectively by the ratio between the diameter of the posterior urethra and the bladder neck in an oblique micturating film at each study [Figure 1]. Urodynamic study was done at 1 week, 6 months, and 1 year following valve ablation using Albyn Phoenix Medical system. Uroflowmetry was performed in patients of toilet trained children only, by a standard filling cytometry filling at the rate of 10 ml/min. The postvoid residual urine (PVR) was assessed by real-time ultrasound within 5 min after voiding if the voided volume (VV) was more than 50 ml. The PVR was estimated by the equation of height × width × depth × 0.52 ml. Bladder capacity (BC) is defined as “VV + PVR,” and expressed as the percentage of expected BC, i.e., (age + 2) ×30 ml. Ultrasonography (USG) was done at 3, 6, and 12 months postvalve ablation. Renal dynamic scan and glomerular filtration rate (GFR) was done after ablation and during follow-up as per clinical judgment. Serial renal function test was done during follow-up and a GFR of 100 ml/min/1.73-m2 of body surface area at more than 2 years of age and 80 ml/min/1.73- m2 of body surface area at age <2 years was considered as normal.
Figure 1: Micturating cystourethrogram film showing ratio between the diameter of posterior urethra and bladder neck A/B

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Statistical analysis was done using paired t-test and multiple serial analyses using ANOVA. P < 0.05 was considered as significant.


  Results Top


A total of 113 patients of COPUM were treated during this period. The age at presentation ranged from newborn period to 10 years in the interventional group and newborn period to 8 years in the control group with mean standard deviation of 3.56 ± 2.84 and 3.81 ± 1.02, respectively. Fifteen (26.3%) and 10 (27.7%) patients have diagnosed antenatally, respectively, in the interventional and control groups. Primary valve ablation was done in 48 (84.2%) patients in the interventional group and in 27 (75%) patients in the control group. A high diversion was needed in 15.7% and 25% of patients of interventional and control groups, respectively. Patients were managed according to the stepladder protocol. Both groups were comparable in terms of age and presenting symptoms. The poor urinary stream was the most common presenting symptoms in both groups. Out of these 93 patients, 17 (18.2%) developed chronic renal failure. Vesicoureteric reflux was seen in 21 (22.5%) patients. The GFR increased in both the group's post valve ablation; however, there was no statistically significant difference in the two groups. The bladder neck hypertrophy (which was measured as a ratio between the diameter of the posterior urethra and bladder neck) at presentation, at first follow-up, and last follow-up is depicted in [Table 1]. The falling trend in bladder neck hypertrophy was analyzed by the repeated measures ANOVA test. The comparison was done between the ratio obtained before the ablation (R1) and the ratio at last follow-up (R3). There was a statistically significant difference in the reduction of bladder neck hypertrophy in the intervention group as compared to the control group at the last follow-up [Table 1]. The urodynamic pattern was abnormal in 70% of patients in both groups [Table 2]. Postvoid residue decreased in the study group as shown in [Table 3]. The uroflowmetry showed a significant increase in the peak urine flow rate as shown in [Table 3].
Table 1: Balder neck hypertrophy in both groups

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Table 2: Urodynamics pattern during follow-up

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Table 3: Bladder capacity, postvoid residue and uroflowmetry postvalve ablation and last follow-up

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  Discussion Top


COPUM is the most common cause of congenital bladder outlet obstruction and occurs in 1 in 5000–8000 live births.[13] In 1919, when Young et al. described the posterior urethral valve (PUV), the reported mean age at presentation was 8.6 years.[14] As the diagnosis has improved in the era of antenatal USG, the majority of cases are detected prenatally. Fifteen patients in the intervention group and ten in the study group were antenatally diagnosed. The presentation in COPUM varied from the poor stream, dribbling of urine due to myogenic failure, and chronic renal failure. The most common presentation in our study group was the poor urinary stream, and straining during micturition, seen in 70% of patients. The presence of bladder neck hypertrophy explains the symptoms of straining at micturition. Primary valve ablation is considered the ideal initial treatment for COPUM. In our study, 75 (80.7%) patients underwent primary valve ablation while 18 (19.3%) needed high diversion in form of bilateral ureterostomies. Various other adjuvant therapeutic modalities have been proposed to treat bladder dysfunction and postponed renal failure. Some authors recommend early aggressive anticholinergic therapy and timed voiding for the management of bladder dysfunction in children with COPUM.[15] Anticholinergic therapy effectively eliminates bladder instability. However, it may increase BC and decreases voiding detrusor pressure, which can lead to myogenic failure. Kajbafzadeh et al. studied the effect of simultaneous bladder neck incision and valve ablations on urodynamic abnormalities in PUV patients.[16] They showed that value ablation along with bladder neck incision resulted in better urodynamic functions. However, the study done by Sarin et al. rebutted the findings of Kajbafzadeh et al.[17] They concluded that though bladder neck incision theoretically improves the outcome of PUV patients, their study failed to demonstrate any significant difference. Recently, α-1 blockers have gained wide attention because of its ability to decrease intravesical pressure and outlet resistance thereby improving voiding dysfunction and upper tract dilatation.[18]

Abraham et al. in a study on 64 patients concluded that there was a reduction of 85% in the pretreatment PVR volume.[11] Kareem and Hassan showed that with the use of doxazocin, 83% of patients showed improvement in their symptoms.[19] The mean postvoid residual volume decreased by 72.7% of the pretreatment mean PVR and the increment in the maximum flow rate was 68.4%. Our study showed that the mean pretreatment PVR in the interventional group decreased from 110 ± 22.62 ml to 15 ± 8.21 ml as compared to the control group. Similarly, there was a significant increase in the mean flow rate of the interventional group from 8.50 ± 2.71 ml/s to 14.3 ± 21 ml/s as compared to the control group (7.1 ± 1.9–8.7 ± 2.3 ml/s) [Table 3]. Based on our data, we believe that the use of α-1 blockers provides the satisfactory outcomes in reducing bladder neck hypertrophy and it should be included in the management protocol of COPUM. Although there are many studies available in the literature regarding the changes in the upper tract and lower tracts after ablation, none of them provide the information regarding the objective measurement of the degree of bladder neck hypertrophy. We, for the first time, tried to measure it objectively in the form of the ratio of urethral and the bladder neck diameter. This ratio takes into account not only bladder neck hypertrophy but also urethral dilatation. It is well known that there is a resolution of posterior urethral dilatation, bladder neck hypertrophy after valve ablation, and it takes months to years for a resolution to happen. Our study demonstrated that the use of alpha-blockers postablation not only hastens the recovery of bladder neck hypertrophy resolution but also improves the urodynamic parameters and mean urine flow rates. These effects are highly desirable in patients of COPUM. This drug is well tolerated by children with minimal side effects. The addition of this therapy during the initial phase of management has the potential to eliminate the need for other measures. There are certain limitations to our study. Being a retrospective in nature is one of them. Measurement of bladder neck hypertrophy is the other major limitation of this study because it was a subjective criterion.


  Conclusion Top


We can safely conclude from this study that the primary modality of treatment in COPUM is valve ablation, and α-1 blockers should be included in the management protocol because of its overall beneficial effect not only on the resolution of bladder neck hypertrophy but also on the urine flow rate and postvoid residue.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Parkhouse HF, Barratt TM, Dillon MJ, Duffy PG, Fay J, Ransley PG, et al. Long-term outcome of boys with posterior urethral valves. Br J Urol 1988;62:59-62.  Back to cited text no. 1
    
2.
Smith GH, Canning DA, Schulman SL, Snyder HM 3rd, Duckett JW. The long-term outcome of posterior urethral valves treated with primary valve ablation and observation. J Urol 1996;155:1730-4.  Back to cited text no. 2
    
3.
Kohaut EC, Tejani A. The 1994 annual report of the North American Pediatric Renal Transplant Cooperative Study. Pediatr Nephrol 1996;10:422-34.  Back to cited text no. 3
    
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Glassberg KI, M Horowitz. Urethral valve and other anomalies of the male urethra. In: Belmon B, King LR, Kramer SA, editors. Clinical Pediatric Urology. London: Dunitz; 2002. p. 899-945.  Back to cited text no. 4
    
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Bajpai M, Dave S, Gupta DK. Factors affecting outcome in the management of posterior urethral valves. Pediatr Surg Int 2001;17:11-5.  Back to cited text no. 5
    
6.
Bajpai M, Pratap A, Tripathi M, Bal CS. Posterior urethral valves: Preliminary observations on the significance of plasma rennin activity as a prognostic marker. J Urol 2005;173:592-4.  Back to cited text no. 6
    
7.
Lopez Pereira P, Espinosa L, Martinez Urrutina MJ, Lobato R, Navarro M, Jaureguizar E. Posterior urethral valves: Prognostic factors. BJU Int 2003;91:687-90.  Back to cited text no. 7
    
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Puri A, Bhatnagar V, Grover VP, Agarwala S, Mitra DK. Urodynamics-based evidence for the beneficial effect of imipramine on valve bladders in children. Eur J Pediatr Surg 2005;15:347-53.  Back to cited text no. 8
    
9.
Aitken KJ, Bägli DJ. The bladder extracellular matrix. Part I: Architecture, development and disease. Nat Rev Urol 2009;6:596-611.  Back to cited text no. 9
    
10.
Austin PF, Homsy YL, Masel JL, Cain MP, Casale AJ, Rink RC. alpha-Adrenergic blockade in children with neuropathic and nonneuropathic voiding dysfunction. J Urol 1999;162:1064-7.  Back to cited text no. 10
    
11.
Abraham MK, Nasir AR, Sudarsanan B, Puzhankara R, Kedari PM, Unnithan GR, et al. Role of alpha adrenergic blocker in the management of posterior urethral valves. Pediatr Surg Int 2009;25:1113-5.  Back to cited text no. 11
    
12.
Bajpai M, Dave S. Prognostic factors in posterior urethral valves and the stepladder protocol. In: Bajpai M, Gearhart JP, Hjalmas K, editors. Progress in Pediatric Urology. Vol. 4. New Delhi: Penwel Publishers; 2001. p. 39-51.  Back to cited text no. 12
    
13.
Rajab A, Freeman NV, Patton M. The frequency of posterior urethral valves in Oman. Br J Urol 1996;77:900-4.  Back to cited text no. 13
    
14.
Young HH, Frontz WA, Baldwin JC. Congenital obstruction of the posterior urethra. J Urol, 3: 289-365, 1919. J Urol 2002;167:265-7.  Back to cited text no. 14
    
15.
De Gennaro M, Capitanucci ML, Capozza N, Caione P, Mosiello G, Silveri M. Detrusor hypocontractility in children with posterior urethral valves arises before puberty. Br J Urol 1998;81 Suppl 3:81-5.  Back to cited text no. 15
    
16.
Kajbafzadeh AM, Payabvash S, Karimian G. The effects of bladder neck incision on urodynamic abnormalities of children with posterior urethral valves. J Urol 2007;178:2142-7.  Back to cited text no. 16
    
17.
Sarin YK, Sinha S. Efficacy of bladder neck incision on urodynamic abnormalities in patients with posterior urethral valves. Pediatr Surg Int 2013;29:387-92.  Back to cited text no. 17
    
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McGuire EJ, Weiss RM. Secondary bladder neck obstruction in patients with urethral valves: Treatment with phenoxybenzamine Urology 1975;5:756-8.  Back to cited text no. 18
    
19.
Kareem DA, Hassan OA. The role of alpha blockers in the treatment of children with voiding dysfunction. Iraqi Postgraduate Med J 2016;15:459-64.  Back to cited text no. 19
    


    Figures

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    Tables

  [Table 1], [Table 2], [Table 3]



 

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