Abstract
Introduction
Primary female bladder neck obstruction is a rare clinical condition characterized by the absence/incomplete bladder neck opening during the voiding phase of micturition.
Methods
We present the cases of two women complaining dysuria, abdominal straining and sensation of incomplete bladder emptying. Videourodynamic evaluation was fundamental for a correct diagnosis.
Results
Videourodynamic evaluation showed a high detrusor pressure during emptying phase, partial use of abdominal strain, very low urine flow rate and significant postvoid residual; imaging showed a defect in the physiological funneling of the bladder neck, absent or incomplete. The first step therapy is represented by oral alpha-blockers and clean intermittent self-catheterization in case of high postvoid residual. Surgical operations, such as bladder neck incision and resection, represent the last option.
Conclusions
In our experience, bladder neck obstruction is a rare condition in women and only a complete clinical evaluation associated with videourodynamic study can lead to an appropriate diagnosis and treatment.
Introduction
Primary female bladder neck obstruction is a clinical condition characterized by the absence/incomplete bladder neck opening during the voiding phase of micturition, whilst bladder pressure increases due to normal detrusor contraction. This condition was first described in males by Marion (1933) and later in female by Diokno and co-workers (1984) and by Axelrod and Blaivas (1987). Only six female were shown presenting that condition (1). Till now, there is no clear definition in medical literature.
During the normal micturition cycle, the first event, during the empting phase, is the relaxation of smooth urethral muscle of the urethra due to local parasympathetic-mediated release of nitric oxide. Afterwards, there is an increase in bladder pressure and the flow of urine begins. Isolated bladder neck constriction does occur when its failure to relax determines an obstacle to the flow of urine, in presence of normal urethral sphincter relaxation and normal bladder contractility.
In literature, only a few cases have been described. In a study by Nitti et al, they found an incidence of 4.6% in a cohort of women undergoing a urodynamic study due to lower urinary tract symptoms (LUTS) complaint (2). The hypotheses about the etiology of the disease are many. Some preliminary studies focused their attention on bladder neck structural changes: the theory of a fibrous narrowing or an hyperplasia was proposed by Marion, whilst Leadbetter theorized the lack of mesenchyme dissolution at the bladder neck or inclusion of abnormal amount of nonmuscolar connective tissue, resulting in hypertrophic smooth muscle, fibrous contractures and inflammatory changes. A neurologic etiology for the disease has also been proposed, as a sympathetic nervous system dysfunction (1).
Case Description
A 30-year-old female patient presented to our Institution in September 2013 complaining voiding symptoms and minimal urinary incontinence, not clearly classifiable if stress or urgency one. She did not use pads. Voiding symptoms were characterized by dysuria, abdominal straining during micturition and feel of incomplete bladder emptying. She had never undergone surgical procedures and did not suffer of any significative medical illness. She had never suffered from urinary tract infections. She did not reported any sexual complaint.
At clinical examination, she had normally developed external genitalia, trophic vaginal mucosa and absence of vaginal prolapse. She had a good pelvic floor contractility with discrete endurance (4 s) and good isolability. Stress and cough test were negative. The lumen of the urethra was explored with bougie a boule up to 24 Ch without evidence of organic stricture. Neurogenic disease had been ruled out. Ultrasound evaluation showed absence of urinary tract dilation, urinary stones, diverticula or bladder mucosal abnormalities. Perineal ultrasound evaluation showed a physiologic appearance and a normal mobility of the urethra and surrounding tissue; transvaginal ultrasound evaluation, done with an empty bladder, showed an increased bladder wall thickness (7.0 mm). Office cistoscopy evidenced a regular urethra and normal appearance of the bladder. The patient underwent a complete pelvic floor rehabilitation program, first.
The first urodynamic evaluation (Tab. I) evidenced a normal filling phase; during the emptying phase, micturition was sustained by a high-pressure detrusor contraction (130 cmH2O) with use of abdominal strain, generating a very low flow (<5 ml/s) with significative postvoid residual volume (180 ml). With the aid of video-urodynamics, we found an incomplete bladder neck opening during the emptying phase (Fig. 1). The urethral outflow was slightly reduced for the whole length of the urethra, but there was no clear evidence of detrusor-sphinteric pseudo-dissynergia.
Urodynamic traces and video-urodynamic imaging evidencing lack of bladder neck opening with high detrusorial pressures and low flow rate during voiding phase.
Videourodynamic imaging evidencing incomplete bladder neck opening and some bladder diverticula during voiding phase.
Urodynamic parameters
The patient was counseled for stress reduction, lifestyle modification and therapy with alpha-blockers (silodosyn 4 mg for the first 2 weeks and then 8 mg daily) has been recommended. During further clinical and video-urodynamic evaluations at 6 and 12 months, a slight reduction in voiding detrusor pressures was found (maintaining average values around 90-100 cm H2O), a reduction in detrusor wall thickness (5 mm) and a little reduction in the subjective voiding symptoms using ICIQ-FLUTS.
A further case concerns a 47-year-old female patient presented to our Institution in October 2015 complaining voiding symptoms and a recent episode of acute urine retention. The urological history starts in the 90s when the patient started complaining of left lumbar flank pain and episodes of stranguria. She did not exhibit any previous medical documentation; however, the anamnestic recall evidenced a diagnosis of a left distal ureteral pathology (not sure if vesico-ureteral reflux, distal ureteral obstruction or mega-ureter) and persistent left kidney hydronephrosis with initial signs of renal failure. In 1997, the patient underwent left ureteral re-implantation with anti-reflux technique and the next year to an intervention of endoscopic ureteral dilatation procedure. Dynamic renal scintigraphy evidenced a significative contraction of the left kidney function and the patient was even offered a left nefrectomy intervention, which was not performed. She did not complain of urological symptoms until 3 months prior to consultation when she complained a further acute urinary retention. A first urodynamic evaluation gave rise to the suspicion of sphynteric hyperactivity and the patient was offered pelvic floor rehabilitation at first. At our clinical evaluation, the patient complained dysuria, urgency (without urge incontinence), use of abdominal strain during micturing and a feel of incomplete bladder emptying. Clinical examination, perineal and transvaginal ultrasound evaluation were similar to those of the previous patient. The lumen of the urethra was explored with bougie a boule up to 22.5 Ch without evidence of organic stricture. Ultrasound evaluation showed monolateral hydronephrosis and absence of urinary stones or bladder mucosal abnormalities. The urodynamic evaluation (Tab. I) evidenced a normal filling phase; during the emptying phase, micturition was sustained by a high-pressure detrusorial contraction (90 cm H2O) with use of abdominal strain, generating a very low flow (<6 ml/s) and with discrete postvoiding residual (120 ml). With the aid of video-urodynamics, we found an incomplete bladder neck funneling during the voiding (Fig. 2). Also in this case, the urethral outflow was slightly reduced for the whole length of the urethra, but there was no clear evidence of detrusor-sphinteric pseudo-dissynergia. The patient was treated with alpha-blockers (silodosyn 4 mg for the first 2 weeks and then 8 mg daily) and was trained for self-intermittent catheterization (performed once a day). The patient reported subjective benefit and significant reduction of voiding symptoms according to ICIQ-FLUTS after 4 months of therapy. A noninvasive urodynamics evidenced an augmentation of maximum flow of 80%, with regular continuous appearance of free flowmetry and nonsignificant postvoid residual. This case represents a late diagnosis of bladder neck obstruction, which could probably be the cause of the vescico-urethral reflux induced from long-time high pressure voiding.
Conclusion
The definition of female bladder outlet obstruction is still a challenge for neuro-urologists. Different definitions have been proposed: Blaivas defined it by urodynamic parameters (Qmax <12 ml/swith pDetQmax >20 cm H2O or inability to void with the transurethral catheter in place despite a sustained detrusor contraction of at least 20 cm H2O) or by radiographic evidence of obstruction in presence of detrusor contraction (at least 20 cmH2O); Chassagne reported different urodynamic parameters (free Qmax <15 ml/s, pDetQmax >20 cm H2O); Nitti considered only radiographic evidence of obstruction without providing for any numerical parameters (2, 3, 4).
Bladder neck obstruction is a rare condition in women. In this complex scenario, video-urodynamics seems to represent the best tool for obtaining a precise diagnosis. In a recent work on 38 women complaining voiding problems, the most frequent findings in video-urodynamics were high-voiding pressure associated with low-flow rate and narrow bladderneck during voiding on simultaneous fluoroscopy examination (5). The use of radioscopic imaging may help in differentiating from sphinteric pseudo-dyssinergia and mid- and distal urethral obstruction. Qian applied a novel diagnostic tool using transperineal sonography and Virtual Touch bladder neck tissue quantification, with measurements that can reflect the bladder neck stiffness and change in texture (6).
The first step therapy is oral alpha-blockers administration that act in smooth muscle relaxation at the level of the bladder neck. They have been largely employed in the male population, representing the mainstream of benign prostatic hyperplasia (BPH) therapy. It is also supposed that they have a role in central and peripheral mechanisms, which have not been adequately described yet. Kumar et al evaluated the efficacy of alpha-blockers in 24 patients with a diagnosis of functional bladder neck obstruction; 12 patients (50%) showed subjective improvement in symptoms, maximum flow rate and postvoid residual with alpha-blocker therapy only. Among 12 non responder patients, six underwent bladder neck incision subsequently and six remained on clean intermittent self-catheterization (7). It should be emphasized that alpha-blockers, as well as other suggested pharmacological therapies (e.g. vaginal diazepam, baclofen, botulinum toxin), are off-label; patients should be well informed that benefit from therapy is uncertain and there is a lack of well-designed, placebo-controlled trials on this topic.
Clean intermittent self-catheterization represent another possible conservative treatment: this maneuver, which generally is lifelong, needs a specific training and has a risk of low urinary tract bacterial colonization and infections. Risk of bladder function deterioration can occur in case of poor compliance to the treatment. This therapy may be useful in combination with alpha-blockers in case of significative postvoid residual in order to reduce irritative symptoms and high-volume residual-associated urinary tract infections (UTIs). Another goal of self-catheterization in high-volume residuals is to reduce the mechanical stress to the detrusor muscle, that in the long time can lead to mechanic detrusor failure.
A short-term experience in a population with men with primary bladder neck obstruction evidenced a good clinical response from endoscopic injection of OnabotulinumtoxinA in the bladder neck (8). This could represent a possible investigational therapeutic opportunity also in well informed women.
Surgical operations, such as bladder neck incision and resection, represent the last option. They are performed under cystoscopic evaluation; hot-knife, LASER probe and resectoscope are all feasable options. We usually perform (with monopolar resectoscope) a single bladder neck incision at 5 o'clock or dual incision, at 5 and 7 o'clock, respectively; only if the result was not satisfying. In one of the largest series of Grønbaek et al, they performed bladder neck incision in 38 women with a diagnosis of bladder neck obstruction. Short-term results evidenced complete symptoms relief in all women at 4 weeks with normalization of flowmetry traces. At 55 months of follow-up, 76% of women were still asymptomatic, whilst most of the others needed to repeat the surgical procedure. Only one patient developed urinary incontinence (9). In our experience, bladder neck incision represent a safe and effective surgical option. All patients treated in our institute have reached complete symptom relief and never needed a second-time procedure. Complications were self-limited and mild (Clavien Dindo Grade 1), mainly transient hematuria and mild sovrapubic pain, and we did not experience any case of urinary retention or urinary incontinence.
In our experience, bladder neck obstruction is a rare condition in women and only a careful clinical evaluation associated with video-urodynamic study can lead to an appropriate diagnosis. It is characterized by voiding symptoms, high-pressure and low-flow voiding dynamics and a characteristic radioscopic narrowing of the bladder neck during micturition phase. Patients are usually young and come to medical attention after having been noticed the problem for many years; sometimes, symptoms already begin during childhood. Oral alpha-blockers are a reasonable first-step therapeutic option, with minimal side effects and benefits in nearly half of the patients. In case of nonresponder patients or in more serious cases, surgical treatment may be considered: incision of the bladder neck offers good long-standing results. Complications such as procedure-related seem to be minimal, with postoperative urinary incontinence occurring in about 3% of patients.
Footnotes
Financial support: No financial support was received for this study.
Conflicts of interest: The authors have no conflicts of interest.