Lower Urinary Tract Obstruction Research Articles

Expectant management of pregnancy involving fetus with lower urinary tract obstruction.

Expectant management of pregnancy involving fetus with lower urinary tract obstruction.

Antenatal Determinants of Postnatal Renal Function in Fetal Megacystis: A Systematic Review.

Introduction: To evaluate the clinical usefulness of demographic data, fetal imaging findings and urinary analytes were used for predicting poor postnatal renal function in children with congenital megacystis. Materials and methods: A systematic review was conducted in MEDLINE's electronic database from inception to December 2023 using various combinations of keywords such as "luto" [All Fields] OR "lower urinary tract obstruction" [All Fields] OR "urethral valves" [All Fields] OR "megacystis" [All Fields] OR "urethral atresia" [All Fields] OR "megalourethra" [All Fields] AND "prenatal ultrasound" [All Fields] OR "maternal ultrasound" [All Fields] OR "ob-stetric ultrasound" [All Fields] OR "anhydramnios" [All Fields] OR "oligohydramnios" [All Fields] OR "renal echogenicity" [All Fields] OR "biomarkers" [All Fields] OR "fetal urine" [All Fields] OR "amniotic fluid" [All Fields] OR "beta2 microglobulin" [All Fields] OR "osmolarity" [All Fields] OR "proteome" [All Fields] AND "outcomes" [All Fields] OR "prognosis" [All Fields] OR "staging" [All Fields] OR "prognostic factors" [All Fields] OR "predictors" [All Fields] OR "renal function" [All Fields] OR "kidney function" [All Fields] OR "renal failure" [All Fields]. Two reviewers independently selected the articles in which the accuracy of prenatal imaging findings and fetal urinary analytes were evaluated to predict postnatal renal function. Results: Out of the 727 articles analyzed, 20 met the selection criteria, including 1049 fetuses. Regarding fetal imaging findings, the predictive value of the amniotic fluid was investigated by 15 articles, the renal appearance by 11, bladder findings by 4, and ureteral dilatation by 2. The postnatal renal function showed a statistically significant relationship with the occurrence of oligo- or anhydramnion in four studies, with an abnormal echogenic/cystic renal cortical appearance in three studies. Single articles proved the statistical prognostic value of the amniotic fluid index, the renal parenchymal area, the apparent diffusion coefficient (ADC) measured on fetal diffusion-weighted MRI, and the lower urinary tract obstruction (LUTO) stage (based on bladder volume at referral and gestational age at the appearance of oligo- or anhydramnios). Regarding the predictive value of fetal urinary analytes, sodium and β2-microglobulin were the two most common urinary analytes investigated (n = 10 articles), followed by calcium (n = 6), chloride (n = 5), urinary osmolarity (n = 4), and total protein (n = 3). Phosphorus, glucose, creatinine, and urea were analyzed by two articles, and ammonium, potassium, N-Acetyl-l3-D-glucosaminidase, and microalbumin were investigated by one article. The majority of the studies (n = 8) failed to prove the prognostic value of fetal urinary analytes. However, two studies showed that a favorable urinary biochemistry profile (made up of sodium < 100 mg/dL; calcium < 8 mg/dL; osmolality < 200 mOsm/L; β2-microglobulin < 4 mg/L; total protein < 20 mg/dL) could predict good postnatal renal outcomes with statistical significance and urinary levels of β2-microglobulin were significantly higher in fetuses that developed an impaired renal function in childhood (10.9 ± 5.0 mg/L vs. 1.3 ± 0.2 mg/L, p-value < 0.05). Conclusions: Several demographic data, fetal imaging parameters, and urinary analytes have been shown to play a role in reliably triaging fetuses with megacystis for the risk of adverse postnatal renal outcomes. We believe that this systematic review can help clinicians for counseling parents on the prognoses of their infants and identifying the selected cases eligible for antenatal intervention.

SFM Fetal Therapy Practice Guidelines: Fetal Cystoscopic Laser Ablation

AbstractFetal lower urinary tract obstruction (LUTO) in a male fetus could cause detrimental effects to the KUB (kidney, ureter, and bladder) system from back-pressure changes as well as to the lungs from reduced amniotic fluid. In a carefully selected case where the obstruction causes progressive damage, a therapeutic intervention could be lifesaving. In utero vesico-amniotic shunting has been shown to improve perinatal pulmonary survival, but evidence on improvement of renal outcomes with this procedure is lacking. More recently, fetal cystoscopic laser fulguration has been shown to be beneficial in longer-term survival and renal outcomes. These interventions carry significant risk, and therefore patient selection and optimal timing are key. This guideline lists the intricacies of patient selection, relevant counseling points and procedural details.

Detection of non-cardiac fetal abnormalities by ultrasound at 11-14 weeks: systematic review and meta-analysis.

To assess diagnostic accuracy of 2D ultrasound at 11-14 weeks gestation as a screening test for individual fetal anomalies and identify screening factors impacting detection. Systematic review and meta-analysis, developed and registered with PROSPERO (CRD42018111781). MEDLINE, EMBASE, Web of Science Core Collection and The Cochrane Library) were searched for studies evaluating the diagnostic accuracy of screening for 16 pre-specified, non-cardiac, congenital anomalies considered to be of interest to the early anomaly scan. We included prospective and retrospective studies from any healthcare setting and low risk, mixed risk and unselected populations. The reference standard was the detection of an anomaly on postnatal or post-mortem examination. Data were extracted to populate 2 x 2 tables and meta-analysis (random-effects model) undertaken to determine the diagnostic accuracy of screening for the pre-specified anomalies (individually and as a composite). Secondary analyses were performed to determine the impact of (1) imaging protocol (2) ultrasound modality (3) publication year and (4) index of sonographer suspicion at time of scan. Post-hoc secondary analysis was conducted to assess performance for studies from 2010. Risk of bias and quality assessment was undertaken for included studies using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). From 5684 citations, 202 papers were identified as eligible and reviewed, resulting in the inclusion of 526,322 fetuses (52 studies) of which 2,399 were affected by one or more of the 16 anomalies. Individual anomalies were not equally amenable to detection on first trimester ultrasound ranging from high (>80%) detection rates for severe conditions including acrania (98%), gastroschisis (96%) and exomphalos (95%) and holoprosencephaly (88%); they were lower for open spina bifida (69%), lower urinary tract obstruction (66%) lethal skeletal dysplasias (57%) and limb reduction defects (50%) and below 50% for facial clefts (43%), polydactyly (40%) and congenital diaphragmatic hernia (38). Conditions with low (<30%) detection rates included bilateral renal agenesis (25%), closed spina bifida (21%), isolated cleft lip only (14%) and talipes (11%). Specificity was >99% for all anomalies. Secondary analysis showed improvement of detection with publication year, and that the use of imaging protocols had a statistically significant impact on screening performance (p<0.0001). Accurate detection of congenital anomalies using first trimester ultrasound is feasible. In this study we have determined screening characteristics for individual anomalies and have shown that detection rates and false positive rates are dependent on the type of anomaly. The use of a standardised protocol allows diagnostic performance to be maximised, and this particularly enhances screening performance for the detection of spina bifida, facial clefts and limb reduction defects. Highlighting the types of anomalies amenable to diagnosis and determining favourable screening test factors can support the development of first-trimester anomaly screening programs. This article is protected by copyright. All rights reserved.

A case of fetal duodenal atresia suspected to be lower urinary tract obstruction.

A case of fetal duodenal atresia suspected to be lower urinary tract obstruction.

SFM Fetal Therapy Practice Guidelines: Fetal Interstitial Laser

AbstractFetal laser therapy was first used in complicated monochorionic pregnancies such as twin-to-twin transfusion syndrome or twin-reversed arterial perfusion sequence. There are some other less common indications such as amniotic band syndrome, chorioangiomas, lower urinary tract obstructions, sacrococcygeal teratomas, and fetal thoracic masses. These practice guidelines discuss the indications, contraindications, and risks of the procedure along with information for patients and draft consent form.

Familial congenital lower urinary tract obstruction (LUTO) suggested by screening for lower urinary tract dysfunction in parents of patients: A descriptive study

AbstractBackgroundCongenital lower urinary tract obstruction (LUTO) describes a heterogeneous group of congenital malformations. Posterior urethral valves (PUV) represent the most common entity. Familial occurrence has been described, suggestive of underlying genetic factors. LUTO can occur in various degrees of severity. In severe forms, oligohydramnios, pulmonary hypoplasia, and renal damage can occur resulting in high pre‐ and postnatal mortality. On the contrary, mild forms may become apparent through recurrent urinary tract infections. Such high phenotypic variability has been described even within the same family. Here, we systematically screened parents of affected children for symptoms of LUTO.MethodsThe study population consisted of parents of LUTO patients. Fathers over 50 years of age were excluded, to avoid inclusion of male phenocopies due to early prostatic hypertrophy. Uroflowmetry, ultrasonography for residual urine and hydronephrosis, and laboratory examination of standard renal retention parameters were assessed, and a detailed patient history was taken, including the assessment of the International Prostate Symptom Score.ResultsTwenty‐nine of 42 LUTO families enrolled were found eligible for the present study. Of these, we identified five families in which the father had already been diagnosed with infravesical obstruction (17%). Of the remaining families, nine agreed to participate in our study. Of these nine families, eight families had a child affected with PUV and one family had a child with urethral stenosis. Here, we found two fathers and one mother with symptoms of LUTO suggestive of mild LUTO and one family, in which the unborn male fetal brother of the affected index patient was also diagnosed prenatally with LUTO.ConclusionOur observations suggest that LUTOs have a higher heritability than previously thought and that first‐degree relatives of the affected should be clinically assessed for symptoms of LUTO.

Palliative Care for Pediatric Urology

Palliative care in the field of urology has largely been limited to adult oncologic conditions. Although there is a plethora of established literature suggesting the advantageous impact of palliative care, there is limited integration of palliative care in adult urology. This underutilization is further exacerbated in pediatric urology, and palliative care in pediatric urology remains an underexplored area despite the prevalence of several life-limiting conditions in this patient population. This paper highlights the potential need for palliative care intervention in a variety of urologic conditions in the pediatric population, including congenital lower urinary tract obstruction, neurogenic bladder dysfunction, exstrophy-epispadias complex, and congenital bilateral renal agenesis. Each condition poses unique challenges that can be addressed with the inclusion of a palliative care team, including decision-making spanning prenatal-neonatal-pediatric periods, acute and chronic symptom management, family relations, body image issues, risk of recurrent hospitalizations and surgeries, and potentially fatal complications. Alongside standard urologic interventions, palliative care can serve as an additional means of addressing physical and psychosocial symptoms experienced by pediatric urology patients to enhance the quality of life of patients and their families.

Fetal lower urinary tract obstruction caused by sacrococcygeal teratoma: A case report

Background: Fetal lower urinary tract obstruction (LUTO) is a rare occurrence that is usually associatedwith major morbidity and mortality after birth. It has an incidence of 2.2 in 10000 pregnancies. In males,the most common cause is persistent posterior urethral valves (50-60%). Other causes include urethralatresia with a poor prognosis. Most fetuses that survive to term with LUTO need dialysis or renaltransplant.Case presentation: A 35-year-old gravida 3 presented for routine antenatal follow-up. Her antenatalfollow-up remained normal until she underwent a growth scan at 33 weeks. Ultrasound revealed a fetuswithin normal growth centiles, but the renal system had features of obstruction. Renal calyces weredilated with hyperechoic renal parenchyma. The bladder was also markedly distended and had athickened wall, and a keyhole sign was present. There was a multicystic lesion in the sacral regionwithout blood flow on Doppler imaging. There was oligohydramnios. She had fetal vesicocentesis, whichrevealed normal kidney function. She had serial fetal vesicocentesis, and renal ultrasound showedimprovement in the corticomedullary differentiation of the kidney. At 38 weeks, the patient underwent acesarean delivery. Imaging studies showed a sacrococcygeal teratoma that was causing pressure on therenal system. This was excised, and the patient was allowed to return home on physiotherapy. Renalfunction test after delivery remained normal.Conclusion: Fetal lower urinary tract obstruction in males is mostly managed using the placement ofvesicoamniotic shunts or stents. In male fetuses with posterior urethral valves, ablation is performed inutero using cystoscopy. In this case report, LUTO was managed by serial vesicocentesis, whichpreserved renal function. In low-resource settings where surgery is not available, serial vesicocentesiscan be performed to relieve obstruction.

Fetal bladder rupture after high-dose maternal opioid treatment: a case report

Abstract Objectives Fetal bladder rupture is rare and mainly caused by lower urinary tract obstruction (LUTO). Our case report describes a rupture at a gestational age of 31 weeks following high-dose maternal opioid exposure during intensive care treatment. Opioids perturb the interplay of afferent and efferent signals between the bladder, urethra, and the central nervous system (CNS) which is crucial in contributing to urinary retention. They rapidly cross the human placenta, affecting also the fetus. To date, there is no clear proof of the connection between maternal opioid treatment and fetal bladder rupture, but the association seems to strengthen. Case presentation A 18-year old first Gravida at 31 weeks of gestation developed a severe sepsis with progressive hypoxic lung failure and need for intubation. During the ICU-treatment, several opioids were administered for sedation and pain relief. Four days after induction of opioid treatment the ultrasound revealed a decompressed fetal bladder, hematoma and significant ascites. Fetal bladder rupture with urinary ascites was suspected. A caesarean section was performed at 33 weeks of gestation due to massive fetal urinary ascites, fetal deterioration and imminent abdominal compartment syndrome. Adequate ventilation and circulation could only be established after percutaneous drainage of 350 mL of abdominal fluid, that was confirmed to be urine. A defect of the bladder was confirmed by ultrasound. On the fifth day of life, the bladder was closed surgically by pediatric surgery. Conclusions Growing awareness of the possible connection between maternal opioid therapy and fetal bladder rupture is necessary to plan follow-up ultrasound examinations to assess the fetal situation.

SUCCESSFUL TRANSURETHRAL RESECTION OF ANTERIOR URETHRAL VALVE IN CHILDREN : A CASE REPORT

Objective: This case report will present transurethral resection of double anterior urethral valves in tertiary hospital. Case(s) Presentation: A three-year-old boy who complained of a poor stream of urine and discomfort during micturition. From the radiological examination, the main finding was found on ultrasound (USG), with thickening of the bladder wall without upper tract abnormality. On panendoscopy, we found double anterior urethral valves at bulbar part and trabeculation in bladder. Discussion: The resection of the valves was performed and achieved an excellent result included normal stream of urine and there was no discomfort during micturition. Conclusion: Anterior Urethral Valve is a rare case that can be caused a lower urinary tract obstruction. A good understanding of AUV’s radiological and endoscopic anatomy is required to differentiate it from other diseases, essential to prevent further injury, and also to decide for appropriate management.&#x0D; Keywords: Anterior Urethral Valve, Congenital Anomaly, Urinary Obstruction

1093 Management and Core Outcomes Set of Fetal Lower Urinary Tract Obstruction: Delphi Consensus

1093 Management and Core Outcomes Set of Fetal Lower Urinary Tract Obstruction: Delphi Consensus

Outcomes of fetal lower urinary tract obstruction based ontiming of oligohydramnios onset.

Fetal Lower Urinary Tract Obstruction (LUTO) is associated with oligohydramnios and significant fetal morbidity, resulting in poor lung development and perinatal death. However, oligohydramnios may develop at different gestational periods, and the impact of timing on fetal outcomes remains unknown. Our objective was to characterize the impact onset of oligohydramnios had on prenatal outcomes. This study is a retrospective cohort study of all patients with a prenatal diagnosis of LUTO at our tertiary referral center from 2014 to 2023. All patients underwent detailed ultrasonography and interdisciplinary counseling and were subsequently delivered at our institution. Data were obtained from electronic medical records and complete extraction was required for final inclusion. During the study time period, 93 patients met inclusion criteria of which 68 (73.1%) developed oligohydramnios during their pregnancy. 63 (93%) of these pregnancies resulted in livebirths with 28 (41.1%) perinatal deaths. Onset of oligohydramnios was earlier in pregnancies with perinatal death (23 vs. 28weeks, p=0.004) and associated with pulmonary hypoplasia. Our data show the impact of oligohydramnios timing in pregnancy on pulmonary hypoplasia and ultimately perinatal death. This allows for detailed patient counseling on the impact oligohydramnios may have on pregnancies by the gestational age of onset.

SFM Fetal Therapy Practice Guidelines: Fetal Shunts

AbstractFetal shunt is placed into the fetus in order to drain fluid from a fluid-filled fetal area into the amniotic cavity. The main indications are hydrothorax, congenital pulmonary airway malformation (CPAM) with dominant cyst, and lower urinary tract obstruction.Fetal shunt is indicated if the hydrothorax is primary or hypertensive. In case of re-accumulation after a diagnostic tap or if the primary hydrothorax has led to a secondary nonimmune hydrops provided the primary nature is clearly established and in cases where gestational age is less than 34 weeks.A shunt in CPAM is indicated in case of CPAM with a dominant cyst where the CPAM volume ratio (CVR) is greater than 1.6, where macrocysts are visible within the lesion, where the diameter of the dominant cyst is more than one-third of the largest diameter of the lesion and where presence of hydrops is not a contraindication for shunting. In case of lower urinary tract obstruction, fetal shunt may be indicated if the following conditions are met. The etiology of lower urinary tract obstruction is posterior urethral valve with oligohydramnios and fetal urinalysis is favorable.

Development and validation of a novel fetal vesico-amniotic shunt, the vortex shunt.

Fetal lower urinary tract obstruction (LUTO) is a severe malformation associated with an up to 80% mortality risk as well as significant renal and pulmonary morbidity in survivors. Fetal vesico-amniotic shunts (VAS) bypass the bladder obstruction, improve amniotic fluid volume and enhance in-utero pulmonary development. VAS has been shown to reduce respiratory morbidity and mortality in the neonatal period without proven benefit on long-term renal and bladder function. Clinically available shunts are associated with an up to 80% dislodgement rate, leading to repeat invasive procedures which increase fetal and maternal risks. We developed a novel "Vortex" shunt, which incorporates enhanced fixation to reduce dislodgement, a one-way valve to optimize in-utero bladder function, and enhanced sonographic echogenicity that optimizes the accurate deployment. Following the validation of these characteristics in initial benchtop experiments we have moved to feasibility studies in the fetal lamb model. We hope that the Vortex shunt may ultimately facilitate shunt deployment, reduce dislodgement risk, improve neonatal morbidity and mortality, and decrease the significant healthcare expenditures associated with long-term morbidity in LUTO survivors. In this manuscript, we review the natural history of LUTO, the risks and benefits of clinically available fetal shunts, and our development and early validation experiments.

A rare congenital anomaly in a female child with acute urinary retention—female hypospadias: a case report

BackgroundFemale hypospadias is a rare congenital anomaly and defined as a female urethral opening on the anterior vaginal wall. Diagnosis is challenging due to its rarity. Different anatomical variations exist depending on the location of the urethral opening. Clinical presentation can vary from asymptomatic until end-stage renal disease due to lower urinary tract obstruction. This case highlights the important clinical and radiological features of female hypospadias. Surgical treatment remains the mainstay management for this entity.Case presentationWe report a case of a 5-year-old girl presented with 3 days of lower abdominal pain, vomiting and difficulty in voiding. She was previously well. Abdominal examination revealed a palpable suprapubic mass arising from the pelvis up to the umbilicus. Perineal examination showed a single opening at the introitus. Ultrasound showed a grossly distended urinary bladder and bilateral mild hydroureteronephrosis. Catheterization of the opening failed to decompress the bladder, and a suprapubic catheter was inserted which drained 500 cc of clear urine. She also developed acute kidney injury which resolved after suprapubic drainage. Cystogram and genitogram failed to delineate the communication between the urinary bladder and vagina. However, cystovaginoscopy revealed a normal vagina opening, and the urethral meatus entered the anterior wall of the vagina distally. She underwent a meatoplasty and recovered well after surgery.ConclusionAttention to important clinical and radiological features helps in the diagnosis of female hypospadias. Female hypospadias should be suspected in female patient with single opening at the introitus, acute urinary retention and failed urinary catheterization. Cystovaginoscopic examination is required to diagnose this condition. Urethroplasty is curative with good outcome for low type of female hypospadias.

Pathological Findings in Fetuses Terminated for Suspected Lower Urinary Tract Obstruction: Experience From a High-Risk Fetal Center in Canada.

Pregnancies complicated by prenatally suspected lower urinary tract obstruction (LUTO) can be associated with high rates of terminations due to potentially poor outcomes. Herein, we assessed autopsy findings of fetuses terminated for suspected LUTO to evaluate the prenatal diagnostic accuracy and spectrum of underlying pathologies. We performed a retrospective review of all pregnancies referred to a high-risk fetal center in a universal access to care health care system for suspected LUTO that opted for termination of pregnancy between 2009 and 2022. Ultrasound features, genetic investigations, placental findings, and distribution of postmortem diagnoses were assessed. Of a total of 190 pregnancies with suspected LUTO evaluated during the study period, 79 (42%) were terminated. We excluded 35 fetuses with incomplete data, resulting in 44 available for analysis. Pregnancies were terminated at a mean gestation of 22 ± 5 weeks. A LUTO diagnosis was confirmed in 37 (84.1%) fetuses (35 males, 2 females), and the remaining 7 showed other pathologies. Pulmonary hypoplasia was found in 62.2% (n = 23) and placental pathologies in 56.8% of confirmed LUTO compared to 33.4% and 71.4% in non-LUTO cases, respectively. Overall, a total of 31 fetuses underwent additional prenatal investigations with genetic anomalies detected only in fetuses with a confirmed LUTO diagnosis (13.6%). In our health care system, almost half of prenatally suspected LUTO pregnancies are terminated. The sonographic diagnostic accuracy for LUTO is reasonable at 84%. However, the remaining 16% still had significant pathologies. Genetic abnormalities are uncommon and rarely the trigger for pregnancy terminations.

Congenital lower urinary tract obstruction with spontaneous fetal bladder rupture due to posterior urethral valves: a case report

BackgroundCongenital lower urinary tract obstruction (LUTO) is a rare but significant condition affecting fetal urinary tract development. LUTO has a range of etiologies, with posterior urethral valves (PUV) being the most common cause. The prenatal diagnosis of LUTO plays a crucial role in recognizing the condition and guiding management decisions. Prenatal ultrasound serves as the primary tool for identifying LUTO, with key findings including megacystis, bladder wall thickening, oligohydramnios, hydronephrosis, and the 'keyhole sign' indicating dilatation of the posterior urethra. We present a case of congenital LUTO with a rare complication of spontaneous fetal bladder rupture and urinary ascites, treated by peritoneo-amniotic shunt placement.Case presentationA 27-year-old pregnant Caucasian women was referred at 28 weeks of pregnancy due to the presence of megacystis and bilateral hydronephrosis on routine ultrasound and suspicion of LUTO. Repeat ultrasound at 29 weeks showed significant fetal ascites, oligohydramnios and resolution of megacystis and hydronephrosis, after which diagnosis of spontaneous bladder rupture was made. Despite ascites aspiration and amnio-infusion, there was persistent ascites and oligohydramnios. A peritoneo-amniotic shunt was placed with resolution of ascites and normalization of the amniotic fluid volume. At 35 weeks, relapse of the megacystis was observed with bilateral pyelectasis and oligohydramnios, possibly due to healing of the bladder rupture, after which elective cesarean section was planned. Cystography confirmed spontaneous healing of the bladder rupture and the presence of posterior urethral valves, which were resected in the neonatal period with cold knife incision. Total follow-up of 8 years continued to show positive ultrasonographic results and good renal function, but the child suffers from bladder dysfunction, manifesting as overactive bladder disease.ConclusionsLUTO might lead to important renal dysfunction and pulmonary hypoplasia in case of increasing disease severity. Spontaneous bladder rupture might improve renal prognosis, acting as a pop-off mechanism by decompression of the urinary tract. However, fetal bladder rupture is rare and only few cases have been reported. Prenatal intervention can be considered for moderate or severe LUTO, but the benefit for long-term outcome remains uncertain and further studies are needed.

Prenatal diagnosis of LUTO- case report and review of the literature

LUTO, or lower urinary tract obstruction refers to a varied group of anatomical abnormalities resulting in an obstruction in the urethra. Development of the urogenital system is an intricate process, with renal anomalies being the most commonly noted. LUTO is seen in approximately 3, in 10,000 live births, two thirds of which are caused by posterior urethral valves (PUV). Posterior urethral valves are membranes within the posterior urethra that can lead to bladder obstruction, hydronephrosis and increased renal pressure. This syndrome occurs almost exclusively in males. We present a case of posterior urethral valve syndrome complicating a pregnancy in the second trimester

OC07.04: Flexible fetal cystoscopy: a novel technique in the treatment of lower urinary tract obstruction

OC07.04: Flexible fetal cystoscopy: a novel technique in the treatment of lower urinary tract obstruction