Urodynamic Changes after Valve Fulguration Alone and Valve Fulguration with Bladder Neck Incision.

AIMS: The aim of this study is to compare urodynamic changes after valve fulguration alone and valve fulguration with bladder neck incision (BNI). SETTINGS AND
DESIGN: A total of 81 patients with posterior urethral valve were treated at our center from July 2010 to July 2016. Patients were randomized into two groups using simple randomization. Forty patients underwent BNI in addition to valve fulguration (Group I), and the remaining 41 patients underwent conventional transurethral valve fulguration (Group II). SUBJECTS AND METHODS: The exclusion criteria for both the groups were the presence of simultaneous urogenital anomalies, any neurological condition, history of any urethral manipulation, and urinary diversion. Urodynamic changes were compared in both groups postoperatively. All patients were evaluated throughout their follow-up, according to the following protocol: (a) Voiding cystourethrography at 6 weeks after surgery; (b) Renal function test and urine culture at 6 weeks and then 3 monthly; (c) Ultrasound kidney, ureter, and bladder region and urodynamics at 3 and 6 months after surgery and then yearly. Median follow-up period for Group I was 27.5 months (13-72 months) and 14 months (14.5-72 months) for Group II. STATISTICAL ANALYSIS USED: Statistical analysis was done using the Student's t-test for parametric data and Chi-square test for categorical variable. P ≤ 0.05 was considered as statistically significant.
RESULTS: The mean age was 7.26 years in Group I and 7.66 years in Group II at the end of follow-up. There was no statistically significant difference found regarding detrusor overactivity (P = 0.68), compliance (P = 0.052), end-filling pressure (P = 0.08), and max Pdet at Qmax (P = 0.08) in the both groups. However, there was a statistically significant difference regarding improvement of peak flow (P = 0.038) and postvoid residue (PVR) (P = 0.045) in Group I in comparison to Group II.
CONCLUSIONS: Valve ablation with BNI gives statistically significant better urodynamics in voiding phase regarding flow and lesser PVR in comparison to valve ablation.

INTRODUCTION

Even after successful valve ablation, bladder dysfunction seems to affect more than 60% of patients of posterior urethral valve (PUV).[1] Many additional treatment modalities are undertaken along with valve fulguration to achieve treatment goals such as anticholinergics, alpha blockers, clean intermittent catheterization (CIC), overnight drainage, and bladder neck incision (BNI). Androulakakis et al. have found endoscopic evidence of prominent hypertrophic semi-closed bladder necks in patients with PUV and myogenic failure.[2] They hypothesize that “voiding under such circumstances may be obstructive at the level of the bladder neck and cause detrusor decompensation by a prolonged and increased bladder outlet resistance.”[2] Similarly, accumulating data have shown the efficacy of alpha blockers in improving voiding dysfunction and upper tract dilatation in patients with PUV, presumably through decreasing intravesical pressure and outlet resistance.[13] To extrapolate the same hypothesis, we prospectively evaluated valve ablation in combination with BNI and simple valve ablation in PUV patients regarding renal function, changes in the upper tract, and urodynamic changes.

SUBJECTS AND METHODS

A total of 90 patients were enrolled in the study between July 2010 and July 2016. A total of 81 patients with PUV were treated at our center. Patients were randomized into two groups using simple randomization. Randomization was done on OPD basis. Forty patients underwent BNI in addition to valve fulguration (Group I), and the remaining 41 patients underwent conventional transurethral valve fulguration (Group II). The exclusion criteria for both groups were the presence of simultaneous urogenital anomalies, any neurological condition, history of any urethral manipulation, and urinary diversion [Figure 1].

Figure 1

Consort diagram

The diagnosis was made by voiding cystometrogram with dilated posterior urethra. This was confirmed by cystoscopy at the time of surgery. Both the groups were compared regarding renal function, changes in the upper tract, and number of episodes of recurrent urinary tract infection both preoperatively and postoperatively. Urodynamic changes were compared in both the groups postoperatively. Patients presenting with raised serum creatinine (Scr) were managed with per urethral drainage and after stabilization, underwent valve fulguration. Valve fulguration was done with right-angled electrode (9 F). The bladder neck incision was given at 7'O clock position. The incision was deep up to bladder neck muscle and from bladder neck to just before verumontanum [Figure 2a and b]. Catheter was removed on 3rd postoperative day.

Figure 2

(a) High bladder neck (b) after bladder neck incision

All patients were evaluated throughout their follow-up according to the following protocol:

Voiding cystourethrography at 6 weeks after surgery

Renal function test and urine culture at 6 weeks and then 3 monthly

Ultrasound KUB region and urodynamics at 3 and 6 months after surgery and then yearly.

Urodynamics was conducted using a Laborie (Dantec, Denmark) multichannel apparatus, and consisted of free voiding uroflowmetry with measurement of the postvoid residue (PVR). The bladder was filled at a constant perfusion rate of 5 ml/min with 0.9% saline at room temperature. The use of microtip transducers on 7 F catheters allowed continuous recording of abdominal and bladder pressures.

The following variables were assessed: Detrusor overactivity (DO); maximum bladder capacity (MBC); bladder compliance; end-filling pressure during filling phase and maximum detrusor pressure at Qmax (Pdetmax); and maximum flow rate, during the voiding phase. PVR obtained by immediate ultrasound after voiding.

The MBC expected for age was calculated using the Koff's formula; MBC (ml) = (age in years + 2) × 30 for children 2–11 years old and (ml) = 7.0 × weight (kg.) for children younger than 2 years and in those aged >12 years to 450 mL.[4] PVR was considered pathological if >10% of MBC during the filling phase of the cystomanometric procedure.

DO was defined as an uninhibited contraction of any magnitude causing incontinence or significant urgency or any uninhibited contraction of >10 cm of H2O during the filling phase, even with no leakage.[1] Myogenic failure (overdistended bladder) was diagnosed when there was an increased MBC associated with a P detmax during voiding of <20 cm of H2O, inability to generate a sustained detrusor contraction, and a PVR of >10% of MBC.[5]

Compliance was measured at 25, 50, 75, and 100% of patient bladder capacity. For detrusor compliance, we used a previously described grading system which is a slight modification of that of Khoury et al.[6] Detrusor compliance was graded as severely impaired –≤10, moderately impaired –10–20, mildly impaired –20–30, and normal –>30 ml/cm water.

Patients with poor compliance and detrusor overactivity on the urodynamic study were treated with anticholinergics. Any change in MBC was measured as a percentage of normal (%MBC). It was graded as below 60, 60–80, 80–100, and 100–150.[7]

Progression of chronic renal failure (CRF), as per the International (NKF-K/DOQI) Classification, was analyzed by evaluating the (Scr) concentrations recorded at the presentation and repeated regularly during the period of follow-up. Median follow-up period for Group I was 27.5 months (13–72 months) and 14 months (14.5–72 months) for Group II. Statistical analysis was done using the Student's t-test for parametric data and Chi-square test. P ≤ 0.05 was considered statistically significant. Written consent of all patients was taken.

RESULTS

The mean age was 7.26 years in Group I and 7.66 years in Group II at the end of follow-up. The mean age of Group 1(valve fulguration with BNI) was 2.45 years, and it was 2.55 years in Group 2(valve fulguration alone) at the time of surgery.

In both groups, preoperatively, all patients had hypercontractile bladder, and detrusor muscle pressures in Group 1 and Group 2 were 202 ± 32 cm of H2O and 194 ± 39 cm of H2O, respectively (P = 0.320 nonsignificant). DO was present in 18.9% of patients in Group I and 23.56% in Group II (P = 0.68). It was associated with low compliance with 14.8% in Group I and 20.59% in Group II. It was associated with leak in 10.8% of patients in Group I and 14.7% in Group II. Mean end-filling pressure in Group I was 40 cm of H2O while it was 31.57 cm of H2O in Group II (P = 0.08).

Mean bladder capacity in the Group I was 229.32 ml while it was 239 ml in Group II. Bladder capacity in comparison to the expected capacity for age was 10.8% and 23.53% in ≤60, 35.14% and 5.88% in 60–80, 18.92% and 35.29% in 80–100, and 35.14% and 35.29% in 100–150, respectively, for Group I and Group II.

Compliance with the Group I was normal in 11.8%, mildly impaired in 13.51%, moderately impaired in 29.73%, and severely impaired in 45.94% in the Group I while it was 26.47%, 17.65%, 23.53%, and 32.35%, respectively, in Group II.

Mean max detrusor pressure at Qmax in Group I was 33.6 cm of H2O while it was 44 cm of H2O in Group II (P = 0.08).

The mean uroflowmetry in Group I was statistically significant (P = 0.038) higher (10.92 ml/min) in comparison to Group II (6.91 ml/min). The mean PVR was also statistically significantly (0.045) lower in Group I (15.41 ml) in comparison to Group II (21.15 ml).

Nearly 10.79% of patients in Group I and 20.59% patients in Group II were put on anticholinergic, having low compliance and detrusor overactivity on urodynamics.

Mean serum creatinine at the time of presentation was 0.90 and 0.92 mg/dl, and at the end of follow-up, it was 0.69 and 0.83 mg/dl (P = 0.049) in Groups I and II, respectively. Similarly, at the end of follow-up, creatinine clearance was 95.4 and 83.5 ml/min/1.73 m2 in Group I and Group II, respectively (P = 0.06). Twenty-four renal units had reflux in Group I while it was 21 in Group II. Reflux resolution was 83.33% and 61.90% in Group I and Group II, respectively (P = 0.048).11% patients in Group I and 23.52% patients in Group II developed chronic kidney disease. Five patients were put on CIC for raised serum creatinine secondary to myogenic failure in Group II [Table 1].

Table 1

Comparison of bladder dynamics in children of two groups, namely bladder neck incision with valve ablation (Group I) and valve ablation (Group II)

DISCUSSION

The reported incidence of voiding dysfunction is 13%–38% after valve ablation.[5] Persistent bladder dysfunction has been implicated as a cause of deterioration of the upper urinary tract and kidney function, and this has lead to the urodynamic investigation of boys with a history of PUV as part of their regular follow-up.[8]

The bladder neck has been recognized as the major cause of bladder outlet obstruction in patients with PUV. However, the concept was largely disputed by Glassberg[3] and Waterhouse,[9] who reported that the bladder neck is not actually narrow. The bladder neck was recently revisited by some authors, who acknowledge that in some PUV cases, there could be a persistent obstructive process secondary to bladder neck dyskinesia.[23]

In our study, there was no significant difference found regarding DO (P = 0.68), compliance (P = 0.052), end-filling pressure (P = 0.08), and max Pdet at Qmax (P = 0.08); however, there was a significant difference regarding peak flow (P = 0.038), PVR (P = 0.045), and renal function (P = 0.049) in the both groups.

Although BNI has proven effective for the treatment of bladder neck obstruction,[10] many urologists are hesitant to use BNI due to possible retrograde ejaculation. Some studies have revealed a 23% to 27% incidence in retrograde ejaculation following bilateral incision of the bladder neck.[1011] However, a much lower incidence is reported in those patients who undergo unilateral BNI. Moisey et al. reported a 16% incidence of retrograde ejaculation following unilateral BNI[12] whereas two other studies demonstrated the preservation of antegrade ejaculation in all patients after unilateral BNI.[1314] It is important to stop the incision before the verumontanum since it does not seem to give any additional relief. Moreover, the ejaculatory ducts open distal to the verumontanum, and extension of the incision to the verumontanum is associated with a higher incidence of retrograde ejaculation (37%).[15]

During the last two decades, the application of BNI for the treatment of patients with PUV has rarely been documented in the literature. Smith et al. reported on four patients, who underwent the bladder neck procedure, but did not include the results.[16] Misseri et al. also reported the application of BNI in one boy with a secondary bladder neck obstruction following PUV.[1] Finally, Androulakakis et al. applied BNI in one boy presenting with myogenic failure long after PUV ablation.

De Gennaro et al.[17] found no clear relation between bladder function and impairment of renal function, and our study also showed no correlation between the type of urodynamic disorder and renal function. Reflux resolution was 83.33% and 61.90% in Group 1 and Group 2, respectively, comparable result found by Kajbafzadeh et al.[18] The major concern in application of BNI is retrograde ejaculation and infertility; however, in our study, patients were not followed up to puberty.

Mean age in our study higher than other studies.[1718] This is due to the delayed presentation of PUV and only 10% of cases diagnosed during the antenatal period in developing countries.[19]

DO was present in 18.9% of patients in Group 1 and 23.56% in Group 2; similar results were found by Ansari et al., Kajbafzadeh et al., and De Gennaro et al.[171820]

There was a significant difference found in both groups regarding uroflowmetry and PVR. A similar result was found by Kajbafzadeh et al.[18]

The strength of the present study is prospective randomized nature, a substantial number of patients in both groups, long follow-up period, and the limitation of study include higher mean age group.

CONCLUSIONS

Valve ablation with BNI gives statistically significant better urodynamics in voiding phase regarding flow and lesser PVR in comparison to valve ablation.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.