PLACEMENT OF ARTIFICIAL URINARY SPHINCTER IN CHILDREN AND SIMULTANEOUS GASTROCYSTOPLASTY

0022-5347/01/1656-2366/0 THE JOURNAL OF UROLOGY® Copyright © 2001 by AMERICAN UROLOGICAL ASSOCIATION, INC.®

Vol. 165, 2366 –2368, June 2001 Printed in U.S.A.

PLACEMENT OF ARTIFICIAL URINARY SPHINCTER IN CHILDREN AND SIMULTANEOUS GASTROCYSTOPLASTY NICHOLAS M. HOLMES, BARRY A. KOGAN

AND

LAURENCE S. BASKIN*

From the Division of Urology, Albany Medical College, Albany, New York, and Department of Urology, University of California San Francisco, San Francisco, California

ABSTRACT

Purpose: Previous studies have described placement of an artificial urinary sphincter and simultaneous augmentation cystoplasty with a segment of bowel. Conclusions from these studies indicated that infection rates were higher and a staged approach should be undertaken. Others have suggested that concurrent urinary reconstruction with stomach and sphincter placement can be performed safely. Results comparing infection rates of simultaneous sphincter placement and gastrocystoplasty versus staged sphincter placement and augmentation cystoplasty using a segment of ileum or stomach versus sphincter placement alone in a pediatric population have not been previously described to our knowledge. We reviewed these various groups of patients to determine if the difference in infectious complications were clinically and statistically significant. Materials and Methods: A retrospective review of medical records from 1986 to 1999 identified 28 pediatric patients (age 18 years or less) who had undergone placement of an AS800† artificial urinary sphincter. Data points were collected focusing on etiology of the neurogenic bladder, age at time of surgery, types of surgery performed, length of followup and complication rates. Results: Complete data were available for 27 of the 28 patients. Neurogenic bladder was secondary to myelomeningocele in 25 cases, transverse myelitis in 1 and spinal cord injury in 2. Mean patient age at surgery was 12.7 years (range 6.1 to 18.2) and mean followup was 4.3 years (range 1 month to 13 years). Simultaneous gastrocystoplasty was performed in 7 cases (group 1), staged sphincter placement followed by augmentation cystoplasty with a segment of ileum or stomach was done in 8 (group 2) and 12 did not require bladder augmentation (group 3). Urethral device erosion requiring explantation was the most common complication, occurring in 3 patients in group 1 and 2 in group 3 (p ⫽ 0.101). Mean time to erosion was 22.1 months (range 2 to 46.4). Previous surgery (bladder neck or hernia repair) was a common factor in each group with complications. Urine cultures and culture of the explanted device were positive in 2 patients in group 1. Conclusions: Simultaneous placement of artificial urinary sphincter at the time of gastrocystoplasty can be performed in carefully selected patients, although those undergoing staged procedures did well without complications. Prior bladder neck surgery seems to be a significant risk for infection. A staged approach to lower urinary tract reconstruction would be more advantageous due to the absence of infection and erosion in those undergoing staged sphincter placement and augmentation cystoplasty. KEY WORDS: urinary sphincter, artificial; infection; bladder, neurogenic

The artificial urinary sphincter is one of the many treatment options for urinary incontinence. Its efficacy in treating incontinence and safety profile in children have been previously reported.1–9 Often the etiology of incontinence is not just due to an incompetent urinary sphincter, but also a result of primary bladder dysfunction. This dysfunction can occur because of decreasing compliance, overactivity or other discoordinated voiding patterns, and clearly affects the upper urinary tract in a deleterious manner resulting in hydronephrosis and worsening renal function. Often bladder augmentation with a segment from the gastrointestinal tract is required to make the bladder a low pressure/normal capacity reservoir. Some patients will require placement of an artificial urinary sphincter and bladder augmentation to facilitate achieving continence. The most significant morbidity of placement of a prosthetic device is the risk of infection. It is thought that this risk is sur-

mountable with proper antibiotic coverage, adherence to strict sterile techniques in the operating room and limiting infectious exposures of the device. Performing simultaneous augmentation cystoplasty with a segment of bowel potentially could violate these principles. Several reports have described a significant increase in infection with artificial urinary sphincter placement and bladder augmentation with bowel.10, 13 Others suggest that using stomach instead of bowel for augmentation may be performed safely with artificial urinary sphincter placement.14, 15 Each of these series included a broad age range of patients including adults. We reviewed an exclusively pediatric cohort of patients (age 18 years or less) who had undergone synchronous sphincter placement and bladder augmentation, a staged surgical approach (sphincter followed by augmentation cystoplasty with ileum or stomach) or sphincter placement alone to determine if the rates of infection/ erosion were clinically and statistically significant among these groups.

* Requests for reprints: Department of Urology, 533 Parnassus Ave., University of San Francisco, San Francisco, California 94143. † American Medical Systems, Inc., Minnetonka, Minnesota. 2366

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TABLE 2. Time to erosion

A retrospective review of medical records from 1986 to 1999 identified 28 pediatric patients who had undergone placement of an AS800 artificial urinary sphincter. All patients underwent preoperative mechanical bowel preparation, and were given intravenous antibiotics and continued oral antibiotics postoperatively. The sphincter cuff was placed around the bladder neck in 27 patients and around the bulbar urethra in 1. All patients continued clean intermittent catheterization postoperatively as implemented under the direction of the attending surgeon. Data points were collected focusing on etiology of the neurogenic bladder, patient age, types of surgery performed, etiology of incontinence, length of followup and complications as a result of device erosion or infection. Cases were further classified into group 1—simultaneous augmentation gastrocystoplasty, group 2—staged surgical approach with sphincter followed by augmentation cystoplasty with ileum or stomach and group 3— bladder augmentation not required. Chisquare analysis was used to determine if the difference in infection or erosion rates was statistically significant. RESULTS

Complete data were available for 27 of the 28 patients. The etiology of urinary incontinence was exclusively due to a neurogenic bladder in all cases. The primary cause of the neurogenic bladder was a result of myelomeningocele in 25 patients, transverse myelitis in 2 and spinal cord injury in 1. Mean patient age at surgery was 12.7 years (range 6.1 to 18.2), and median followup was 3.3 years (range 1 month to 13 years). Group 2 had a longer median followup of 6.5 years, probably as a result of the changing urodynamics parameters of the bladder after placement of the sphincter (table 1). There were 7 patients in group 1, 8 in group 2 and 12 in group 3. Sphincter placement was performed initially due to an incompetent urinary sphincter in group 2. Later augmentation cystoplasty with a segment of ileum (5 patients) or gastric patch (3) was performed due to changing urodynamic parameters, that is decreasing bladder compliance, increased storage pressures and so forth (mean time to augmentation 3.52 years, range 1.1 to 8.3). Urethral device erosion requiring explantation as a result of infection was the most common complication occurring in 43% (3 of 7 patients) of group 1 and 17% (2 of 12) of group 3 (table 1). The differences in erosion rates were not statistically significant (chi-square p ⫽ 0.101). Overall device erosion rate was 18.5% (5 of 27 patients). Mean time to erosion after implantation of the sphincter was 22.1 months (range 2 to 46.4, table 2). Of the 27 patients 3 had a history of traumatic catheterization but none of them had urethral device erosion. A common factor identified in the patients with urethral device erosion was previous surgery of the genitourinary system or inguinal region, including bladder neck surgery in 4 and inguinal hernia repair in 1. Bladder neck surgery had been performed a mean of 4.2 years (range 1 to 8) before placement of the artificial urinary sphincter. No other patients had previous bladder neck surgery for achieving continence. Urine cultures and cultures of the explanted device were performed, and were positive for Staphylococcus epidermidis and ␤-streptococcus in 1 patient each in group 1. All patients had overlying skin changes suggesting infection (erythema, induration and so forth) in the areas where the pump mechanism or reservoir was located.

Erosion Time (mos.) Group 1: Pt. 1 Pt. 2 Pt. 3 Group 3: Pt. 4 Pt. 5

7.5 27.2 46.4 2.0 27.2

DISCUSSION

The challenge of treating urinary incontinence in the pediatric patient as a result of neurogenic dysfunction has produced numerous surgical procedures. With augmentation cystoplasty and artificial urinary sphincter, successful continence has been achieved in those with neurogenic bladder and incompetent urinary sphincter. An extended review of the literature clearly demonstrated the superiority of placing an artificial urinary sphincter to maintain continence and lower morbidity in comparison to other surgical procedures.16 The major morbidity with placement of any prosthetic device is infection. Strict adherence to sterile surgical principles has lowered the present infection rate for the artificial urinary sphincter to 4.5% according to a meta-analysis review of published series.17 Some would argue that introduction of a gastrointestinal segment with augmentation cystoplasty and simultaneous artificial urinary sphincter placement violates this principle. The surgical case is no longer “clean” and has been converted to a “clean contaminated” case. Violating this issue of sterility could increase infection rates and potential morbidity. Despite vigorous mechanical bowel preparation, large and small bowel segments are not completely sterile with comparable significant bacterial counts.12 In several studies simultaneous augmentation cystoplasty with bowel and artificial urinary sphincter placement infectious complication rates have ranged from 20% to 50%.11, 12 Chronic bacterial colonization in patients undergoing augmentation with segments of bowel has been well described and the inevitable urinary tract infection may also facilitate infectious complications of the artificial urinary sphincter.18 Use of a gastric patch rather than the intestinal segments to augment the bladder would be ideal for simultaneous artificial urinary sphincter and augmentation cystoplasty due to lower bacterial counts at surgery. Previous studies have shown that this technique can be performed simultaneously with infection rates no greater than those of staged procedures.14, 15 Simultaneous placement of an artificial urinary sphincter and cystoplasty were preferentially recommended. In our series the infection or erosion rate in the simultaneous gastrocystoplasty and artificial urinary sphincter group was 43% (3 of 7 patients) versus no infections or erosions in those undergoing staged procedures, although patients with neurogenic bladder have been shown to have an increased incidence of prosthetic infections.19 The difference in the infection rates did not reach statistical significance probably due to the small numbers in each group. It would appear that if a patient requires surgery to enlarge bladder capacity and increase urethral resistance then a staged approach may be less morbid. Mean time to infection or erosion of the device was almost 2 years, which would suggest that surgical mishap might not

TABLE 1. Patient stratification

Group 1: gastrocystoplasty ⫹ artificial urinary sphincter simultaneous Group 2: staged artificial urinary sphincter ⫹ augmentation Group 3: artificial urinary sphincter only

No. Pts.

Median Followup (yrs.)

% Erosion/Infection Rate (No./total No.)

7 8 (ileum 5, gastric 3) 12

3.0 6.5 2.2

43 (3/7) 0 (0/8) 17 (2/12)

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be the cause except in 1 group 3 patient. Causes of this delayed infection or erosion could be a result of tissue ischemia and atrophy from inappropriate cuff size or previous bladder neck surgery. Theoretically, traumatic catheterization could also help introduce bacteria to the pseudocapsule formation around the prosthetic device. The pseudocapsule can be penetrated by bacteria and adherence to it has been demonstrated on electron microscopy.20, 21 Bacilluria has been reported in up to two-thirds of patients treated with gastrocystoplasty despite the hostile acidic environment due to gastric secretions,22 which may account for those in group 1 with infection of the eroded sphincter. CONCLUSIONS

The use of the artificial urinary sphincter for treatment of incontinence with simultaneous augmentation cystoplasty is feasible but does have considerable risk of infection or erosion. Patients undergoing staged procedures with the initial sphincter placement followed by bladder augmentation did well without any infections or erosions. Identifiable factors for those at risk for potential erosion or infection are previous surgery especially bladder neck reconstruction or inguinal hernia repair, and such patients probably should undergo staged procedures. The delay in time to infection or erosion suggests that contamination of the artificial urinary sphincter device may not occur at surgery and may be a result of chronic bacterial colonization from catheterization and trauma during catheterization, allowing bacteria to seed the prosthetic device. REFERENCES

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bladder. J Urol, 154: 769, 1995 6. Levesque, P. E., Bauer, S. B., Atala, A. et al: Ten-year experience with artificial urinary sphincter in children. J Urol, 156: 625, 1996 7. Fulford, S. C. V., Sutton, C., Bales, G. et al: The fate of the ’modern’ artificial urinary sphincter with a followup of more than ten years. Br J Urol, 79: 713, 1997 8. Simeoni, J., Guys, J. M., Mollard, P. et al: Artificial urinary sphincter implantation for neurogenic bladder: a multiinstitutional study of 107 children. Br J Urol, 78: 287, 1999 9. Kryger, J. V., Barthold, J. S., Fleming, P. et al: The outcome of artificial urinary sphincter after a mean 15 year followup in a pediatric population. Br J Urol, 83: 1026, 1999 10. Gearhart, J. P., Albertsen, P. C., Marshall, F. F. et al: Pediatric applications of augmentation cystoplasty: the Johns Hopkins experience. J Urol, 136: 430, 1986 11. Strawbridge, L. R., Kramer, S. A., Castillo, O. A. et al: Augmentation cystoplasty and the genitourinary sphincter. J Urol, 142: 297, 1989 12. Light, J. K., Lapin, S. and Vohra, S.: Combined use of bowel and the artificial urinary sphincter in reconstruction of the lower urinary tract: infectious complications. J Urol, 153: 331, 1995 13. Theodorou, C. H., Plastiras, D., Moutizouris, G. et al: Combined reconstructive and prosthesis surgery in complicated lower urinary tract dysfunction. J Urol, 157: 472, 1997 14. Ganesan, G. S., Nguyen, D. N., Adams, M. C. et al: Lower urinary tract reconstruction using stomach and the artificial urinary sphincter. J Urol, 149: 1107, 1993 15. Miller, E. A., Kwan, M. and Mitchell, M.: Simultaneous augmentation cystoplasty and artificial urinary sphincter placement: infection rates and voiding mechanisms. J Urol, 160: 750, 1998 16. Kryger, J. V., Gonzalez, R. and Barthold, J. S.: Surgical management of urinary incontinence in children with neurogenic sphincteric incompetence. J Urol, 163: 256, 2000 17. Hajlvassilou, C. A.: A review of complications and results of implantation of the AMS artificial urinary sphincter. Eur Urol, 35: 36, 1999 18. Fenn, N., Conn, I. G., German, K. A. et al: Complications of clam enterocystoplasty with particular reference to urinary tract infection. Br J Urol, 69: 366, 1992 19. Kaablin, J. and Kessler, R.: Infectious complications of penile prosthesis surgery. J Urol, 139: 953, 1988 20. Nickel, J. C., Heaton, J., Morales, A. et al: Bacterial biofilm in persistent penile prosthesis-associated infection. J Urol, 135: 586, 1986 21. Montague, D.: Periprosthetic infections. J Urol, 138: 68, 1987 22. Kurzrock, E. A., Baskin, L. S. and Kogan, B. A.: Gastrocystoplasty: long-term followup. J Urol, 169: 2182, 1998