This Month in Pediatric Urology

Article Outline

• Bulking Agent Injection for Persistent Incontinence and Neurogenic Bladder Dysfunction
• New Tissue Bulking Substance Eliminates Vesicoureteral Reflux
• Alpha Blocker Therapy for Primary Bladder Neck Dysfunction
• Diagnostic Evaluation of Daytime Incontinence
• Evaluation and Treatment of Monosymptomatic Enuresis
• Copyright

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Bulking Agent Injection for Persistent Incontinence and Neurogenic Bladder Dysfunction 

Achieving continence in the patient with a neurogenic bladder secondary to spina bifida often requires increasing outlet resistance. With limitations in pharmacological management, surgery is typically required. Multiple techniques are available with selection usually based on surgeon preference, indicating that there is no clear successful advantage of any one technique. When failure occurs following bladder neck reconstruction alternative therapies are pursued.

Minimally invasive endoscopic injection of a bladder neck bulking agent has been reported with variable results. De Vocht et al (page 719) from Utrech, the Netherlands report the long-term assessment of bladder neck injection therapy following failure of a bladder neck fascial sling in 27 children with a mean age of 8 years. Retrograde and antegrade approaches were used. The bulking agent was polydimethylsiloxane in 89% of the cases and dextranomer/hyaluronic copolymer in 11%. Neither the technique nor agent affected the outcome. Only 2 patients achieved continence after 1 injection, while continence was not achieved in 12 after 2 injections or in 8 after 3 injections. Bladder deterioration resulted in ileocystoplasty in 2 patients and botulinum A toxin administration in 1. No patient suffered significant complications. While endoscopic injection of a bladder neck bulking agent is an enticing option following bladder neck reconstruction failure, its success is limited regardless of the variable. The authors acknowledge the fact that their study sample was small but conclude that overall success using a bulking agent is low and repeated injections are ineffective.

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New Tissue Bulking Substance Eliminates Vesicoureteral Reflux 

The most widely used materials for endoscopic correction of vesicoureteral reflux include dextranomer/hyaluronic acid and polydimethylsiloxane. While both agents are highly effective, each has its own shortcoming due to biodegradability or the need for specialized injection equipment. Ormaechea et al (page 714) from Argentina and Brazil investigated polyacrylate polyalcohol copolymer for endoscopic treatment of vesicoureteral reflux. This material is nonbiodegradable, synthetic in origin and easy to inject using a standard 23 gauge needle. After injection a fibrotic capsule develops, providing long-term stability and permanence. The particles on average are 300 μ in diameter, reducing the risk for local or distant migration. A total of 88 ureters in 61 patients were injected for grade II (36%), III (47%), IV (14%) and V (3%) reflux. Overall, reflux resolved in 89% of the renal units and 84% of patients. A voiding cystourethrogram 1 year after injection revealed resolution of grade II reflux in 100% of ureters, grade III in 88%, and grades IV and V in 67%. Complications included dysuria in 10% of patients, lumbar pain in 7% and febrile episodes in 5%. The success rate reported by the authors is similar to that of other endoscopic agents. The authors conclude the nonbiodegradable characteristics of polyacrylate polyalcohol copolymer may prolong its effectiveness, making it an attractive alternative to current agents.

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Alpha Blocker Therapy for Primary Bladder Neck Dysfunction 

The diagnosis of primary bladder neck dysfunction (PBND) in a child may be more elusive than the treatment as often children are treated unsuccessfully for an overactive bladder. PBND is characterized by incomplete opening of the bladder neck in a patient with a nonneurogenic condition. It is objectively identified with urodynamic parameters of prolonged opening time, depressed uroflow despite a relaxed external sphincter and no concomitant urethral obstruction. PBND can be diagnosed noninvasively based on uroflow and pelvic floor electromyography (EMG) lag time.

Van Batavia et al (page 724) from New York, New York summarize the basic understanding of PBND and its significance in children and adults. They identified 51 patients with a mean age of 11.6 years with PBND based on uroflow and EMG findings, clinical history and symptoms. EMG lag time, maximum and average flow rates, and post-void residuals were measured. Alpha blocker therapy was initiated at half the adult dose (50 patients took tamsulosin). At a mean followup of 46 months average and maximum flow rates increased from 7 to 12.4 and 12.4 to 20.3 cc per second, respectively, EMG lag time decreased from 30.8 to 5.8 seconds and post-void residual decreased from 46 to 13.9 ml, all statistically significant. Maximal improvement was achieved within 6 to 8 weeks of initiation of therapy in 63% of patients but only 25% reported symptomatic improvement of the lower urinary tract symptoms. No major side effects were identified. However, pretreatment levels of average and maximum flow rates, EMG lag time and post-void residual returned in 11 patients who stopped using the medication after sustained improvement for 2 years.

The authors note that PBND is more common than previously suspected and the lack of improvement in children with lower urinary tract symptoms may be due to misdiagnosis. They consider PBND a problem that can be treated but rarely cured. It is also apparent that objective urodynamic parameters improve before patient perception and, therefore, long-term therapy is prudent. The authors conclude that PBND should be considered and treated when children complain primarily of hesitancy with voiding.

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Diagnostic Evaluation of Daytime Incontinence 

On behalf of the International Children's Continence Society, Hoebeke et al (page 699) summarize the findings of an international panel of experts on standardizing the initial evaluation of daytime incontinence. They make no intent to discuss therapy. Daytime incontinence is clearly defined and placed in perspective with achieving other normal milestones. The authors highlight the essential parameters of the current problem obtained from the child's perspective assessing whether the incontinence is continuous or intermittent and present during the day or night. They describe the important aspects that must be documented from the medical history, family history and bowel habits.

Questionnaires and a scoring system are used to facilitate a better understanding of current voiding habits but it is recognized that few instruments are validated. Diaries of at least 3 days are the best concrete appraisal of the voiding habits and should include fluid intake, voided output, episodes of urgency and the amount of urine lost. Physical examination can provide insight into appropriate bladder and bowel emptying via abdominal palpation and generalized neurological assessment. Diagnostic testing is kept to a minimum and typically includes a urinalysis and ultrasonography. Uroflow studies, when performed appropriately, can provide important details about the voiding habits and help determine when more formal urodynamic testing is required. The authors provide a succinct organized approach to the evaluation of children with voiding dysfunction to help the practitioner develop a consistent pattern of care.

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Evaluation and Treatment of Monosymptomatic Enuresis 

Neveus et al (page 441) report on a multi-institutional collaborative project from the International Children's Continence Society on establishing a basic foundation for the evaluation and treatment of children with monosymptomatic enuresis (MNE). The authors indicate that this clinical problem can be managed by primary care physicians and the intent of the article is to provide the primary care physician or nurse practitioner with a foundation for management and treatment. When treating MNE it is critical to rule out other confounding factors such as daytime lower urinary tract symptoms, urinary infections and constipation. While the etiology of MNE is multifactorial, the 3 components that have a primary influence are nocturnal polyuria, detrusor overactivity and increased arousal thresholds.

The basis for treatment begins with understanding the problem, and the importance of a careful and complete history obtained from the child with corroborative information from the parent to eliminate comorbid conditions that potentially result in therapeutic resistant nocturnal enuresis. A history of daytime voiding with a weak stream, straining to void or continuous incontinence should trigger a referral to a specialized center. Diagnostic testing can initially be limited to urinalysis specifically looking for glucosuria, proteinuria, polyuria and bacteriuria. Routine ultrasonography is not typically necessary. A diary of voiding habits before initiation of therapy is helpful.

Treatment is approached in a basic and systematic fashion beginning with the importance of changing general lifestyle, diet and voiding patterns. Specific options of the nocturnal enuretic alarm, desmopressin, anticholinergics and tricyclic antidepressants are discussed along with the advantages, disadvantages and guidelines for each modality. The authors also provide recommendations of how to treat the therapy resistant child. While there is little evidence-based medicine to support any of the treatment plans, the recommendations are based on best practice management by leaders in the major pediatric urology societies. This is a logical approach to take for children with MNE and serves as an excellent resource for primary care colleagues.