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Augmentation Ureterocystoplasty
0022-5347/93/1495-1095$03.00/0 THE JOURNAL OF UROLOGY Copyright © 1993 by AMERICAN UROLOGICAL ASSOCIATION, INC.
Vol. 149, 1095-1098, May 1993
Printed in U. S.A.
AUGMENTATION URETEROCYSTOPLASTY J. STUART WOLF, JR.* AND CHARLES W. TURZAN From the Departments of Urology, University of California School of Medicine, San Francisco and Kaiser Permanente Medical Center, Oakland, California
ABSTRACT
Augmentation cystoplasy using the gastrointestinal tract has disadvantages related to the intestinal resection and its incorporation into the urinary tract. To preclude both sets of complications, we performed augmentation ureterocystoplasty in a 51f2-year-old meningomyelocele patient with urinary incontinence, a low capacity bladder, severe vesicoureteral reflux and a poorly functioning kidney. After nephrectomy the ureter was incised longitudinally, folded over and placed onto the bladder as a patch. Bladder capacity, only 60 cc without the contribution from the refluxing upper tract, increased to 200 cc 6 months postoperatively. The patient is continent. Augmentation ureterocystoplasty is an option for bladder enlargement that obviates many of the risks associated with enterocystoplasty. KEY WORDS: bladder, neurogenic; meningomyelocele; postoperative complications; ureter; urinary diversion
Augmentation with gastrointestinal tissue has become the standard treatment for patients with a noncompliant, low capacity or hyperreflexic bladder when nonoperative management fails. Although the procedures have proved to be effective, the potential for complications is significant. Electrolyte abnormalities, excessive mucus production, calculi, recurrent infections and altered drug metabolism are well documented problems associated with enterocystoplasty, secondary to the incorporation of bowel into the urinary tract, that are seen after only a short interva1. 1 The use of stomach decreases the severity of some of these phenomena but may be associated with metabolic alkalosis, the hematuria/dysuria syndrome or peptic ulceration of the augmentation. 2,3 Long-term studies are currently uncovering the risks of growth retardation 1 and neoplasms4 attributable to enterocystoplasty. The intestinal reaction alone can be the source of many complications, including abscess formation, enteric fistulas, several types of bowel obstruction and malabsorption. Spontaneous perforation of the enteric augmented bladder can occur.5 Investigation of bladder augmentation has led to use of a myriad of materials and methods, primarily in animal models and including biological materials, such as (myo}peritoneal flaps,6 de-epithelialized bowel,7 placenta,8 dura,9 omentum/o preserved bladder grafts l l and bovine pericardium. 12 Synthetic materials, such as acrylic molds,13 polytetrafluoroethylene (Teflon) felt/ 4 silicone rubber 15 and polyvinyP6 or gelatin 17 sponge, also have been used. Autoaugmentation is the only alternative to enterocystoplasty for clinical use recently described in the literature. 18 We report our experience with another form of bladder augmentation. CASE HISTORY
A 51f2-year-old boy with meningomyelocele was admitted to the hospital with right pyelonephritis. History was notable for excision of an infected urachal cyst. Persistent hydrocephalus had required multiple revisions of a ventriculoperitoneal shunt. There was high grade vesicoureteral reflux on the right side, with this kidney contributing less than 5% of the overall renal function by 99"'technetium -mercaptoacetyltriglycene renal scan. On a regimen of 5 mg. oxybutynin orally 3 times daily cystometry had previously demonstrated a urinary capacity (including the refluxing upper tract) of 100 cc with a pressure of 23 cm. water. Although the perineal electromyographic activity had Accepted for publication October 16, 1992. * Requests for reprints: Department of Urology, U-575, University of California, San Francisco, California 94143-0738.
FIG. 1. Cystogram demonstrates trabeculated bladder and severe reflux with hydroureteronephrosis. Total capacity, including refluxing upper tract, is approximately 100 cc.
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FIG. 2. A, bladder and ureter with proposed lines of incision. B, bladder and ureter are opened. C, ureter is folded once, and then will be folded partially over again. D, completed augmentation ureterocystoplasty.
been minimal, there was no urine leakage at this volume. Despite catheterizations every 3 to 4 hours he experienced urinary incontinence. The patient improved clinically after treatment with intravenous antibiotics. The creatinine level was 0.3 mg./dl. (adult normal 0.5 to 1.5). A cystogram demonstrated a low capacity trabeculated bladder with severe vesicoureteral reflux and hydroureteronephrosis (fig. 1). On February 13, 1992 the right kidney was removed and the ureter was transected at its upper end using an extraperitoneal flank approach. Through a lower midline incision the bladder and right ureter were exposed extraperitoneally. Cystometry demonstrated the capacity of the
entire system to be 95 cc and that of the isolated bladder (after occluding the right ureterovesical junction) to be 60 cc. The bladder was split open in the midline and the ureter was opened longitudinally on its anterior aspect to the level of the iliac vessels (fig. 2, A and B). The ureter was folded into a C and then into a partial S shape, and the edges were approximated with a running synthetic absorbable suture (fig. 2, C). The patch was brought down into the bladder incision and fixed into place with a running synthetic absorbable suture (fig. 2, D). Cystotomy and urethral catheters were placed, and the pelvis was drained with a closed suction system. Convalescence was uneventful. Cystometrography 4 months
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FIG. 3. Cystogram of augmented bladder 4 months postoperatively. Capacity is 150 cc with pressure of 24 cm. water. A, anteroposterior view. B, oblique view reveals the distal unincised ureter.
after the procedure revealed the bladder capacity to be 150 cc at a pressure of 24 cm. water (fig. 3). A repeat study 6 months postoperatively demonstrated further increase in the capacity, with a pressure of 25 cm. water at 200 cc volume. There was no infection or urinary incontinence. DISCUSSION
Performing augmentation ureterocystoplasty, rather than enterocystoplasty, precluded the general complications due to resection of bowel and its incorporation into the bladder. Specific to our patient, the presence of meningomyelocele and a ventriculoperitoneal shunt made this procedure even more advantageous. The majority of enterocystoplasty complications appear to occur in patients with myelodysplasia. 5 , 19 Children with myelodysplasia may suffer fecal incontinence following intestinal resection. 20 Ventriculoperitoneal shunts are at risk for infection when enterocystoplasty is performed21 and have been reported to perforate through an enteric augmented bladder.22 Finally, the opportunity to avoid intraperitoneal dissection in a patient with a history of an infected urachal cyst and multiple ventriculoperitoneal shunt revisions was welcomed. Although necessary if there is infection and poor function, removal of a refluxing upper tract further decreases urinary capacity in a patient with a contracted bladder. With ureterocystoplasty added to the urological armamentarium the bladder can be enlarged with little morbidity beyond that of the nephrectomy. Even if nephrectomy is not absolutely required, augmentation using the ureter is likely to be less morbid than enterocystoplasty. Important technical points include the ureteral dissection, incision and folding. The periureteral tissue should be disturbed as little as possible, since the vascularization of the mobilized (supra-iliac) ureter will depend on flow through adventitial capillary networks supplied from below. Fortunately, the dilated and tortuous ureter seems to have a generous collateral circulation. The ureteral incision is extended from anterolateral to anteromedial as it moves toward the iliac vessels, equivalent to opening the lumen on its antimesenteric border. With each folding over of the ureteral patch the volume added doubles. 23 Creative configurations of the ureteral segment are required to maximize the volume of the augmentation. In our patient, for example, the volume of the ureteral segment alone was somewhat less than 35 cc. After folding the patch approximately 1112 times a volume of 90 cc was added to the bladder by the time of the initial postoperative evaluation. The refluxing ureter is compliant unless compromised by infection. It appears that the compliance is maintained in the augmentation as demonstrated by the increase in capacity from 4 to 6 months. Long-term
evaluation will nonetheless be necessary to assess fully the course of this type of augmentation. In summary, augmentation ureterocystoplasty was performed in a boy with meningomyelocele, a neurogenic bladder, severe vesicoureteral reflux and a poorly functioning kidney. This procedure may be used for bladder augmentation in the presence of a dilated ureter. It avoids the potential complications of enterocystoplasty related to gastrointestinal resection and incorporation into the urinary tract, while achieving the goal of a low pressure bladder with adequate capacity. ADDENDUM
Since this original report we have performed augmentation ureterocystoplasty on 2 additional patients. Because nephrectomy was not required, we used transureteroureterostomy to drain the upper ureter of the more dilated system into the contralateral ureter. There were no perioperative complications, and bladder capacity and compliance have increased in both patients. Dr. Barry Kogan encouraged this endeavor and provided the preoperative urodynamic studies. REFERENCES
1. McDougal, W. S.: Metabolic complications of urinary intestinal diversion. J. Urol., 147: 1199, 1992. 2. Ganesman, G. S., Mitchell, M. E., Nguyen, D. H., Adams, M. C. and Burns, M. W.: Bladder reconstruction using stomach: 73 patients and 6 years later. J. Urol., part 2, 147: 253A, abstract 158,1992. 3. Reinberg, Y., Manivel, J. C., Froemming, C. and Gonzalez, R: Perforation of the gastric segment of an augmented bladder secondary to peptic ulcer disease. J. Urol., 148: 369, 1992. 4. Filmer, R B. and Spencer, J. R: Malignancies in bladder augmentations and intestinal conduits. J. Urol., 143: 671, 1990. 5. Bauer, S. B., Hendren, W. H., Kozakewich, H., Maloney, S., Colodny, A. H., Mandel, J. and Retik, A. B.: Perforation of the augmented bladder. J. Urol., part 2, 148: 699, 1992. 6. Weingarten, J. L., Cromie, W. J. and Paty, R J.: Augmentation myoperitoneocystoplasty. J. Urol., 144: 156, 1990. 7. Motley, R C., Montgomery, B. T., Zollman, P. E., Holley, K. E. and Kramer, S. A.: Augmentation cystoplasty utilizing de-epithelialized sigmoid colon: a preliminary study. J. Urol., 143: 1257,1990. 8. Fishman, 1. J., Flores, F. N., Scott, F. B., Spjut, H. J. and Morrow, B.: Use of fresh placental membranes for bladder reconstruction. J. Urol., 138: 1291, 1987. 9. Kelami, A.: Lyophilized human dura as a bladder wall substitute: experimental and clinical results. J. Urol., 105: 518, 1971. 10. Goldstein, M. B. and Dearden, L. C.: Histology of omentoplasty of the urinary bladder in the rabbit. Invest. Urol., 3: 460, 1966.
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11. Tsugi, I., Ishida, H. and Fujieda, J: Experimental cystoplasty using preserved bladder graft. J. Urol., 85: 42, 1961. 12. Novick, A. C., Straffon, R A., Banowsky, L. H., Nose, Y., Levin, H. and Stewart, B. H.: Experimental bladder substitution using biodegradable graft of natural tissue. Urology, 10: 118, 1977. 13. Bohne, A. W. and Urwiller, K L.: Experience with urinary bladder regeneration. J. Urol., 77: 725, 1957. 14. Kelami, A., Dustmann, H. 0., Liidtke-Handjery, A., Carcamo, V. and Herold, G.: Experimental investigations of bladder regeneration using Teflon-felt as a bladder wall substitute. J. Urol., 104: 693, 1970. 15. Stanley, T. H., Feminella, J. G., Jr., Priestley, J. B. and Lattimer, J. K: Subtotal cystectomy and prosthetic bladder replacement. J. Urol., 107: 783, 1972. 16. Kudish, H. G.: The use of polyvinyl sponge for experimental cystoplasty. J. Urol., 78: 232, 1957.
17. Orikasa, S. and Tsuji, I.: Enlargement of contracted bladder by use of gelatin sponge bladder. J. Urol., 104: 107, 1970. 18. Cartwright, P. C. and Snow, B. W.: Bladder autoaugmentation: early clinical experience. J. Urol., part 2, 142: 505, 1989. 19. Khoury, J. M., Timmons, S. L., Corbel, L. and Webster, G. D.: Complications of enterocystoplasty. Urology, 40: 9, 1992. 20. Gonzalez, R and Cabral, B. H. P.: Rectal continence after enterocystoplasty. Dial. Ped. Urol., 10: 4, December 1987. 21. Kreder, K J., Webster, G. D. and Oakes, W. J.: Augmentation cystoplasty complicated by postoperative ventriculoperitoneal shunt infection J. Urol., 144: 955, 1990. 22. Mevorach, R A., Hulbert, W. C., Merguerian, P. A. and Rabinowitz, R: Perforation and intravesical erosion of a ventriculoperitoneal shunt in a child with an augmentation cystoplasty. J. Urol., 147: 433, 1992. 23. Hinman, F., Jr.: Atlas of Urologic Surgery. Philadelphia: W. B. Saunders Co., p. 535, 1989.
Vol. 149, 1095-1098, May 1993
Printed in U. S.A.
AUGMENTATION URETEROCYSTOPLASTY J. STUART WOLF, JR.* AND CHARLES W. TURZAN From the Departments of Urology, University of California School of Medicine, San Francisco and Kaiser Permanente Medical Center, Oakland, California
ABSTRACT
Augmentation cystoplasy using the gastrointestinal tract has disadvantages related to the intestinal resection and its incorporation into the urinary tract. To preclude both sets of complications, we performed augmentation ureterocystoplasty in a 51f2-year-old meningomyelocele patient with urinary incontinence, a low capacity bladder, severe vesicoureteral reflux and a poorly functioning kidney. After nephrectomy the ureter was incised longitudinally, folded over and placed onto the bladder as a patch. Bladder capacity, only 60 cc without the contribution from the refluxing upper tract, increased to 200 cc 6 months postoperatively. The patient is continent. Augmentation ureterocystoplasty is an option for bladder enlargement that obviates many of the risks associated with enterocystoplasty. KEY WORDS: bladder, neurogenic; meningomyelocele; postoperative complications; ureter; urinary diversion
Augmentation with gastrointestinal tissue has become the standard treatment for patients with a noncompliant, low capacity or hyperreflexic bladder when nonoperative management fails. Although the procedures have proved to be effective, the potential for complications is significant. Electrolyte abnormalities, excessive mucus production, calculi, recurrent infections and altered drug metabolism are well documented problems associated with enterocystoplasty, secondary to the incorporation of bowel into the urinary tract, that are seen after only a short interva1. 1 The use of stomach decreases the severity of some of these phenomena but may be associated with metabolic alkalosis, the hematuria/dysuria syndrome or peptic ulceration of the augmentation. 2,3 Long-term studies are currently uncovering the risks of growth retardation 1 and neoplasms4 attributable to enterocystoplasty. The intestinal reaction alone can be the source of many complications, including abscess formation, enteric fistulas, several types of bowel obstruction and malabsorption. Spontaneous perforation of the enteric augmented bladder can occur.5 Investigation of bladder augmentation has led to use of a myriad of materials and methods, primarily in animal models and including biological materials, such as (myo}peritoneal flaps,6 de-epithelialized bowel,7 placenta,8 dura,9 omentum/o preserved bladder grafts l l and bovine pericardium. 12 Synthetic materials, such as acrylic molds,13 polytetrafluoroethylene (Teflon) felt/ 4 silicone rubber 15 and polyvinyP6 or gelatin 17 sponge, also have been used. Autoaugmentation is the only alternative to enterocystoplasty for clinical use recently described in the literature. 18 We report our experience with another form of bladder augmentation. CASE HISTORY
A 51f2-year-old boy with meningomyelocele was admitted to the hospital with right pyelonephritis. History was notable for excision of an infected urachal cyst. Persistent hydrocephalus had required multiple revisions of a ventriculoperitoneal shunt. There was high grade vesicoureteral reflux on the right side, with this kidney contributing less than 5% of the overall renal function by 99"'technetium -mercaptoacetyltriglycene renal scan. On a regimen of 5 mg. oxybutynin orally 3 times daily cystometry had previously demonstrated a urinary capacity (including the refluxing upper tract) of 100 cc with a pressure of 23 cm. water. Although the perineal electromyographic activity had Accepted for publication October 16, 1992. * Requests for reprints: Department of Urology, U-575, University of California, San Francisco, California 94143-0738.
FIG. 1. Cystogram demonstrates trabeculated bladder and severe reflux with hydroureteronephrosis. Total capacity, including refluxing upper tract, is approximately 100 cc.
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WOLF AND TURZAN
FIG. 2. A, bladder and ureter with proposed lines of incision. B, bladder and ureter are opened. C, ureter is folded once, and then will be folded partially over again. D, completed augmentation ureterocystoplasty.
been minimal, there was no urine leakage at this volume. Despite catheterizations every 3 to 4 hours he experienced urinary incontinence. The patient improved clinically after treatment with intravenous antibiotics. The creatinine level was 0.3 mg./dl. (adult normal 0.5 to 1.5). A cystogram demonstrated a low capacity trabeculated bladder with severe vesicoureteral reflux and hydroureteronephrosis (fig. 1). On February 13, 1992 the right kidney was removed and the ureter was transected at its upper end using an extraperitoneal flank approach. Through a lower midline incision the bladder and right ureter were exposed extraperitoneally. Cystometry demonstrated the capacity of the
entire system to be 95 cc and that of the isolated bladder (after occluding the right ureterovesical junction) to be 60 cc. The bladder was split open in the midline and the ureter was opened longitudinally on its anterior aspect to the level of the iliac vessels (fig. 2, A and B). The ureter was folded into a C and then into a partial S shape, and the edges were approximated with a running synthetic absorbable suture (fig. 2, C). The patch was brought down into the bladder incision and fixed into place with a running synthetic absorbable suture (fig. 2, D). Cystotomy and urethral catheters were placed, and the pelvis was drained with a closed suction system. Convalescence was uneventful. Cystometrography 4 months
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AUGMENTATION URETEROCYSTOPLASTY
FIG. 3. Cystogram of augmented bladder 4 months postoperatively. Capacity is 150 cc with pressure of 24 cm. water. A, anteroposterior view. B, oblique view reveals the distal unincised ureter.
after the procedure revealed the bladder capacity to be 150 cc at a pressure of 24 cm. water (fig. 3). A repeat study 6 months postoperatively demonstrated further increase in the capacity, with a pressure of 25 cm. water at 200 cc volume. There was no infection or urinary incontinence. DISCUSSION
Performing augmentation ureterocystoplasty, rather than enterocystoplasty, precluded the general complications due to resection of bowel and its incorporation into the bladder. Specific to our patient, the presence of meningomyelocele and a ventriculoperitoneal shunt made this procedure even more advantageous. The majority of enterocystoplasty complications appear to occur in patients with myelodysplasia. 5 , 19 Children with myelodysplasia may suffer fecal incontinence following intestinal resection. 20 Ventriculoperitoneal shunts are at risk for infection when enterocystoplasty is performed21 and have been reported to perforate through an enteric augmented bladder.22 Finally, the opportunity to avoid intraperitoneal dissection in a patient with a history of an infected urachal cyst and multiple ventriculoperitoneal shunt revisions was welcomed. Although necessary if there is infection and poor function, removal of a refluxing upper tract further decreases urinary capacity in a patient with a contracted bladder. With ureterocystoplasty added to the urological armamentarium the bladder can be enlarged with little morbidity beyond that of the nephrectomy. Even if nephrectomy is not absolutely required, augmentation using the ureter is likely to be less morbid than enterocystoplasty. Important technical points include the ureteral dissection, incision and folding. The periureteral tissue should be disturbed as little as possible, since the vascularization of the mobilized (supra-iliac) ureter will depend on flow through adventitial capillary networks supplied from below. Fortunately, the dilated and tortuous ureter seems to have a generous collateral circulation. The ureteral incision is extended from anterolateral to anteromedial as it moves toward the iliac vessels, equivalent to opening the lumen on its antimesenteric border. With each folding over of the ureteral patch the volume added doubles. 23 Creative configurations of the ureteral segment are required to maximize the volume of the augmentation. In our patient, for example, the volume of the ureteral segment alone was somewhat less than 35 cc. After folding the patch approximately 1112 times a volume of 90 cc was added to the bladder by the time of the initial postoperative evaluation. The refluxing ureter is compliant unless compromised by infection. It appears that the compliance is maintained in the augmentation as demonstrated by the increase in capacity from 4 to 6 months. Long-term
evaluation will nonetheless be necessary to assess fully the course of this type of augmentation. In summary, augmentation ureterocystoplasty was performed in a boy with meningomyelocele, a neurogenic bladder, severe vesicoureteral reflux and a poorly functioning kidney. This procedure may be used for bladder augmentation in the presence of a dilated ureter. It avoids the potential complications of enterocystoplasty related to gastrointestinal resection and incorporation into the urinary tract, while achieving the goal of a low pressure bladder with adequate capacity. ADDENDUM
Since this original report we have performed augmentation ureterocystoplasty on 2 additional patients. Because nephrectomy was not required, we used transureteroureterostomy to drain the upper ureter of the more dilated system into the contralateral ureter. There were no perioperative complications, and bladder capacity and compliance have increased in both patients. Dr. Barry Kogan encouraged this endeavor and provided the preoperative urodynamic studies. REFERENCES
1. McDougal, W. S.: Metabolic complications of urinary intestinal diversion. J. Urol., 147: 1199, 1992. 2. Ganesman, G. S., Mitchell, M. E., Nguyen, D. H., Adams, M. C. and Burns, M. W.: Bladder reconstruction using stomach: 73 patients and 6 years later. J. Urol., part 2, 147: 253A, abstract 158,1992. 3. Reinberg, Y., Manivel, J. C., Froemming, C. and Gonzalez, R: Perforation of the gastric segment of an augmented bladder secondary to peptic ulcer disease. J. Urol., 148: 369, 1992. 4. Filmer, R B. and Spencer, J. R: Malignancies in bladder augmentations and intestinal conduits. J. Urol., 143: 671, 1990. 5. Bauer, S. B., Hendren, W. H., Kozakewich, H., Maloney, S., Colodny, A. H., Mandel, J. and Retik, A. B.: Perforation of the augmented bladder. J. Urol., part 2, 148: 699, 1992. 6. Weingarten, J. L., Cromie, W. J. and Paty, R J.: Augmentation myoperitoneocystoplasty. J. Urol., 144: 156, 1990. 7. Motley, R C., Montgomery, B. T., Zollman, P. E., Holley, K. E. and Kramer, S. A.: Augmentation cystoplasty utilizing de-epithelialized sigmoid colon: a preliminary study. J. Urol., 143: 1257,1990. 8. Fishman, 1. J., Flores, F. N., Scott, F. B., Spjut, H. J. and Morrow, B.: Use of fresh placental membranes for bladder reconstruction. J. Urol., 138: 1291, 1987. 9. Kelami, A.: Lyophilized human dura as a bladder wall substitute: experimental and clinical results. J. Urol., 105: 518, 1971. 10. Goldstein, M. B. and Dearden, L. C.: Histology of omentoplasty of the urinary bladder in the rabbit. Invest. Urol., 3: 460, 1966.
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11. Tsugi, I., Ishida, H. and Fujieda, J: Experimental cystoplasty using preserved bladder graft. J. Urol., 85: 42, 1961. 12. Novick, A. C., Straffon, R A., Banowsky, L. H., Nose, Y., Levin, H. and Stewart, B. H.: Experimental bladder substitution using biodegradable graft of natural tissue. Urology, 10: 118, 1977. 13. Bohne, A. W. and Urwiller, K L.: Experience with urinary bladder regeneration. J. Urol., 77: 725, 1957. 14. Kelami, A., Dustmann, H. 0., Liidtke-Handjery, A., Carcamo, V. and Herold, G.: Experimental investigations of bladder regeneration using Teflon-felt as a bladder wall substitute. J. Urol., 104: 693, 1970. 15. Stanley, T. H., Feminella, J. G., Jr., Priestley, J. B. and Lattimer, J. K: Subtotal cystectomy and prosthetic bladder replacement. J. Urol., 107: 783, 1972. 16. Kudish, H. G.: The use of polyvinyl sponge for experimental cystoplasty. J. Urol., 78: 232, 1957.
17. Orikasa, S. and Tsuji, I.: Enlargement of contracted bladder by use of gelatin sponge bladder. J. Urol., 104: 107, 1970. 18. Cartwright, P. C. and Snow, B. W.: Bladder autoaugmentation: early clinical experience. J. Urol., part 2, 142: 505, 1989. 19. Khoury, J. M., Timmons, S. L., Corbel, L. and Webster, G. D.: Complications of enterocystoplasty. Urology, 40: 9, 1992. 20. Gonzalez, R and Cabral, B. H. P.: Rectal continence after enterocystoplasty. Dial. Ped. Urol., 10: 4, December 1987. 21. Kreder, K J., Webster, G. D. and Oakes, W. J.: Augmentation cystoplasty complicated by postoperative ventriculoperitoneal shunt infection J. Urol., 144: 955, 1990. 22. Mevorach, R A., Hulbert, W. C., Merguerian, P. A. and Rabinowitz, R: Perforation and intravesical erosion of a ventriculoperitoneal shunt in a child with an augmentation cystoplasty. J. Urol., 147: 433, 1992. 23. Hinman, F., Jr.: Atlas of Urologic Surgery. Philadelphia: W. B. Saunders Co., p. 535, 1989.