Correspondence *Department of Urology Children's Hospital Boston, 300 Longwood Avenue, Boston, MA 02115, USA

Email stuart.bauer@childrens.harvard.edu

Original article

Lottmann HB et al. (2006) Long-term effects of dextranomer endoscopic injections for treatment of urinary incontinence: an update of a prospective study of 31 patients. J Urol 175: 1485–1489   PubMed

Synopsis

Background

Endoscopic treatment for urinary incontinence is an attractive alternative to major continence surgery because it is less invasive and has lower costs and hospitalization times; however, there is a shortage of long-term data on bulking agents, and there are concerns regarding their safety and durability.

Objective

To report the long-term results of endoscopic injections of a dextranomer–hyaluronic-acid copolymer for the treatment of urinary incontinence.

Design and intervention

Between September 1997 and September 2004, this prospective study recruited patients aged 5–20 years old with severe incontinence caused by sphincter deficiency. Patients with vesicoureteral reflux, poor bladder compliance, or uncontrolled overactive bladder were excluded. Endoscopic dextranomer–hyaluronic-acid injections were performed under general anesthesia via a flexible cystoscopic injection needle. Males were injected along the posterior urethra, proximal to the verumontanum; females were injected along the urethra. Continence and bladder capacity were assessed using videourodynamics, renal ultrasound, and subjective reports at 1, 6, and 12 months, and annually thereafter. Patients with only a partial response or recurrence of symptoms underwent another round of endoscopic treatment.

Outcome measures

The main endpoint was continence status; response to treatment was defined as dry (dryness interval of 4 h) or improved (use of 1 pad daily).

Results

Of 33 patients enrolled (25 males, 8 females), 16 had neuropathic bladder, 13 had exstrophy–epispadias complex, and 4 had bilateral ectopic ureters. Mean age was 10.3 years (range 5–18 years). Sixteen patients underwent one treatment session, thirteen underwent two treatment sessions, and four underwent three treatment sessions before achieving a definitive response. The mean injected volume per session was 3.9 ml (range 1.6–12 ml). There were no major complications. The response rates after 3, 4, 5, 6, and 7 years' follow-up were 50%, 48%, 43%, 36%, and 40%, respectively. The response rate for patients who underwent >1 treatment session was 47%. Response rates were similar for patients with neuropathic bladder (50%), exstrophy (50%), and epispadias (43%), and higher for patients with bilateral ectopic ureters (75%). The response rate was higher among males (57%) compared with females (38%). Over half of the patients who had been treated with bladder-neck plasty before endoscopic injection were either dry or improved (58%), and 67% patients with small bladders before endoscopic treatment had increased bladder capacity. Four patients developed bladder deterioration and recurrent leakage, and underwent augmentation. No implant-related adverse effects were reported.

Conclusion

With up to 7 years' follow-up, this study demonstrates the long-term safety and durability of dextranomer–hyaluronic-acid injections for the treatment of structural urinary incontinence in children.

Commentary

Pediatric patients with urinary incontinence secondary to structural abnormalities can be difficult to manage. Continence can be achieved via a variety of surgical procedures, including bladder-neck reconstruction, fascial slings, urethral lengthening, and the artificial urinary sphincter. Endoscopic injection of bulking agents to the bladder neck is a minimally invasive modality that, historically, has not resulted in durable continence, but that continues to evolve with the availability of newer, improved bulking agents. Lottmann et al. provide us with the first long-term efficacy data for injection of dextranomer–hyaluronic acid—a nonmigratory, nonallergenic, nonmutagenic, and nonimmunogenic polymer—for the treatment of structural urinary incontinence in children. The study is an update of a prospective study of 31 patients that was initiated in 1997 and closed in 2004. Patients included in the study had a mean age of 10.3 years and had urinary incontinence due to exstrophy–epispadias complex, neuropathic bladder, or bilateral ectopic ureters. The mean volume of dextranomer–hyaluronic acid injected was 3.9 ml, and all patients were injected in retrograde fashion transurethrally via a cystoscope. Treatment outcomes were primarily measured with determination of continence (wet versus dry pads). Patients also underwent videourodynamics. Overall, 16 patients were treated once, 13 treated twice, and 4 patients were treated 3 times.

In their previous report, the majority of patients had a follow-up period of 3 years, and 50% still had a dry or improved response at that time.¹ In the present update, a variable number of patients were eligible for evaluation at years 4 to 7, and dry-or-improved rates ranged from 36% to 48%. The success rates were comparable in patients with exstrophy–epispadias complex and neuropathic bladder (43–50%), and were higher in patients with bilateral ectopic ureters (75%). In addition, the success rate was higher in male patients than in female patients (57% versus 38%, respectively). Treatment outcomes were not affected by a history of bladder-neck surgery. There were no adverse effects related to the dextranomer–hyaluronic acid, and the authors conclude that dextranomer–hyaluronic acid is a viable option as primary therapy or as a rescue procedure for patients who have undergone previous, failed, bladder-neck surgery.

Continence rates of 70–100% have been reported following bladder-neck reconstruction,^{2, 3, 4} and open surgical procedures are the gold standard in the treatment of structural incontinence in children. In another recent, long-term study of continence following injection of the bulking agent polydimethylsiloxane, the dry-or-improved rate was 47% at a mean of 6 years.⁵ These data, and those provided by Lottmann et al. in the current study, indicate that endoscopic injection of dextranomer–hyaluronic acid is a reasonable first or salvage option to offer patients and families with the difficult burden of urinary incontinence. The acceptability of predicted success rates will depend on the perspective and expectations of the patient and his or her family.

Appropriately, Lottmann et al. caution that parents should not be given overly optimistic information regarding expected success. The pediatric urologist must be prepared to re-treat several times, and to address the bladder neck with an open surgical procedure in the 50% of patients in whom endoscopic treatment fails.

Acknowledgments

The synopsis was written by Sandra Ford, Associate Editor, Nature Clinical Practice.

References

1. Lottmann HB et al. (2002) The effect of endoscopic injections of dextranomer based implants on continence and bladder capacity: a prospective study of 31 patients. J Urol 168: 1863–1867 | Article | PubMed | ChemPort |
2. Cole EE et al. (2003) Outcome of continence procedures in the pediatric patient: a single institutional experience. J Urol 170: 560–563 | Article | PubMed |
3. Shimada K et al. (2002) Surgical management of urinary incontinence in children with anatomical bladder-outlet anomalies. Int J Urol 9: 561–566 | Article | PubMed |
4. Salle JL et al. (1997) Urethral lengthening with anterior bladder wall flap (Pippi Salle procedure): modifications and extended indications of the technique. J Urol 158: 585–590 | PubMed | ChemPort |
5. Guys JM et al. (2006) Endoscopic injection with polydimethylsiloxane for the treatment of pediatric urinary incontinence in the neurogenic bladder: long-term results. J Urol 175: 1106–1110 | Article | PubMed | ChemPort |

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Subject areas under which this article appears: Pediatric urology | Urinary incontinence, urodynamics and lower urinary tract dysfunction