Journal of Indian Association of Pediatric Surgeons
Journal of Indian Association of Pediatric Surgeons
                                                   Official journal of the Indian Association of Pediatric Surgeons                           
Year : 2017  |  Volume : 22  |  Issue : 4  |  Page : 202--206

Preperitoneal bladder augmentation: Feasibility and results


Dhruva Nath Ghosh1, Sampath Karl2, Sudipta Sen3,  
1 Department of Pediatric Surgery, Christian Medical College, Ludhiana, Punjab, India
2 Department of Pediatric Surgery, Christian Medical College, Vellore, Tamil Nadu, India
3 Department of Pediatric Surgery, PSG Institute of Medical Sciences, Coimbatore, Tamil Nadu, India

Correspondence Address:
Dhruva Nath Ghosh
Department of Pediatric Surgery, Christian Medical College & Hospital, Ludhiana, Punjab - 141 008
India

Abstract

Introduction: Bladder augmentation is an important part of pediatric reconstructive urology. This study was conducted to assess the feasibility and results of our technique of preperitoneal bladder augmentation. Materials and Methods: Thirty-three children underwent preperitoneal bladder augmentation for small inelastic bladders who had failed medical management or needed undiversion. The underlying diagnosis included neurogenic bladder, valve bladder, bladder exstrophy, non-neurogenic neurogenic, ectopic ureters, and urogenital sinus. The operative procedure involved placing the entire augmentation in the preperitoneal or subcutaneous space after bivalving the native bladder. The augment segment of the bowel with its pedicle was brought into the preperitoneal space through a small opening in the parietal peritoneum. A Mitrofanoff port was also provided where needed. Results: Preperitoneal augmentation provided an adequately compliant, good volume bladder except in children with bladder exstrophy or previous abdominal surgery. There was a good cystometric recovery, with resolution of hydronephrosis and incontinence. Vesicoureteral reflux resolved in 24 of 26 units. In the 13 children who were uremic preoperatively, there was a significant decrease in serum creatinine levels, although 9 children continued to have supra-normal serum creatinine. Surgical complications seen were within expectations. There was no incidence of intraperitoneal leak, which is the main projected benefit of this procedure over the traditional “intraperitoneal” method of augmentation. Conclusions: The preperitoneal augmentation provides an adequate, safe, and low-pressure reservoir of urine except in cases of bladder exstrophy and previous abdominal surgery.



How to cite this article:
Ghosh DN, Karl S, Sen S. Preperitoneal bladder augmentation: Feasibility and results.J Indian Assoc Pediatr Surg 2017;22:202-206


How to cite this URL:
Ghosh DN, Karl S, Sen S. Preperitoneal bladder augmentation: Feasibility and results. J Indian Assoc Pediatr Surg [serial online] 2017 [cited 2019 Sep 15 ];22:202-206
Available from: http://www.jiaps.com/text.asp?2017/22/4/202/214443


Full Text

 Introduction



Bladder augmentation is an important treatment modality in children with small or inelastic bladders.[1],[2] The union of the bladder with a bowel segment is, however, not always without trouble and can lead to a variety of surgical and metabolic complications including malignancy.[3],[4] Intraperitoneal leak of urine due to perforation of the augment, adhesive intestinal obstruction, and development of calculi are the important surgical complications.[5],[6]

Perforation of the reservoir, with an incidence of 6%–10%, results in peritonitis and can be fatal.[7] Catheter trauma, chronic infection, avulsion of adhesions between the bowel patch and peritoneum, overdistension, and bowel ischemia are among the proposed mechanisms of perforation.[8]

Isolation of the augmented bladder from the peritoneal cavity by placing the augmentation in a preperitoneal space should lower the incidence of intraperitoneal leakage of urine. Subsequent surgery to the augmented bladder can be performed without entering the peritoneal cavity which would be an additional advantage of preperitoneal bladder augmentation.

We present the results of with the procedure in 33 children where the augmented bladder was placed in a preperitoneal space, and we report our technique with its postoperative evaluation.

 Materials and Methods



The study was approved by the Institutional Review Board and the University Ethics Committee (vide register no. 18043301) and it was part of a postgraduate dissertation.

Thirty-three children (22 males) underwent preperitoneal augmentation cystoplasty in a 5-year period. The primary diagnosis was neurogenic bladder (n = 18), bladder exstrophy (n = 5), valve bladder (n = 6) non-neurogenic neurogenic (n = 2), and one case each of bilateral single system ectopic ureters and urogenital sinus. Indications for augmentation included incontinence (n = 23), increasing hydronephrosis (n = 16), recurrent urinary infection (n = 10), and uremia (n = 13). Two children were on urinary diversion and four were on chronic catheter drainage before augmentation.

The mean age at surgery was 6 years. Twelve children had had one or more abdominal surgeries before augmentation.

The preoperative mean serum creatinine in these 33 children was 0.98 mg/dl (standard deviation [SD] = 0.62). Thirteen children were uremic (serum creatinine >1 mg/dl), with a mean serum creatinine of 1.96 mg/dl (SD = 0.72). The mean serum creatinine of the uremic children had become 1.5 mg/dl (SD = 0.7) before augmentation after preoperative drainage and other corrective measures.

Preoperative evaluation revealed 15 normal kidneys and 49 hydronephrotic kidneys while 2 kidneys were dysplastic.

A preoperative voiding cystourethrogram revealed 26 refluxing units. Twenty-four bladders were heavily trabeculated while seven were of small capacity.

Preoperative cystometric studies were available in 23 patients. We defined safe capacity as the bladder capacity where the pressure remains below 20 cm of water; however, many children in our series had massive reflux, and thus estimation of safe capacity and compliance was not truly indicative of the state of the bladder. Eight children had preoperative detrusor instability. Video urodynamics was not available in our center.

Augmentation was done due to the failure of medical management or as an undiversion procedure.

Technique

A transverse incision was placed approximately 1.5 cm below the umbilicus and deepened to reach the rectus sheath. The inferior skin and subcutaneous tissue flap are raised till the level of the pubic symphysis. The superior tissue flap was raised to the level of the umbilicus. The anterior rectus sheath was opened longitudinally on either side just lateral to the linea alba, and the preperitoneal space was developed till the iliac vessels are visualized on either side, and the native bladder was exposed.

The recti are now divided at the level of the skin incision [Figure 1]a.{Figure 1}

The peritoneum was then opened posterior to the bladder, and the appropriate bowel segment was mobilized.

The selected bowel segment was then brought out to the preperitoneal space along with its pedicle through a small opening in the anterior parietal peritoneum [Figure 1]b. Bowel continuity was restored.

The bladder was bivalved, taking special care to prevent tears in the peritoneum lying posterior to the bladder. This lateral mobilization of the bladder halves creates a wide V-shaped gap between them to receive the posterior part of the bowel patch [Figure 1]c.

The bowel segment was detubularized and used to augment the bladder. A Mitrofanoff port when needed was also delivered through a small opening in the parietal peritoneum and sited at the umbilicus.

The sigmoid colon was the most commonly used bowel segment (n = 27). Augmentation was done with grossly dilated ureters (n = 4), ileum (n = 1), and ileocecum (n = 1).

During closure of the abdomen, each rectus muscle was sutured at the level of its division, but any midline closure was avoided. This produces an artificial divarication of the recti in the lower abdomen and results in the augmented bladder to sit comfortably in a large preperitoneal space bounded by the peritoneum and posterior rectus sheath posteriorly and the subcutaneous tissue anteriorly [Figure 1]d. Catheters are brought out through one of the recti.

Refluxing units were managed by augmentation alone, reimplantation into the native bladder or bowel, or refluxing to nonrefluxing transureteroureterostomy. Thirty-two children had a concomitant Mitrofanoff procedure.

 Results



The mean follow-up was 44.3 months (range: 8–65 months).

Thirty-one children had good continence with dry intervals of more than 3 h while two bladder exstrophy children remained incontinent. Subsequently, one of these children had a bladder neck division while the other child has had a Young-Dees-Leadbetter bladder neck plasty.

The mean serum creatinine after augmentation was 0.94 mg/dl (SD = 0.88). Nine uremic children still had a serum creatinine above 1 mg/dl though there was a significant fall in the mean serum creatinine from 1.9 mg/dl to 1.4 mg/dl (P = 0.011).

All preoperative hydronephrotic units have shown improvement or stabilization on postoperative ultrasonography.

Reflux resolution was seen in 24 of the 26 refluxing units [Figure 2]. Persistent reflux was seen in one unit that did not have an antireflux procedure while the other unit was reimplanted into the bowel segment. One of these children continued to have recurrent urinary infection and underwent a refluxing to nonrefluxing transureteroureterostomy.{Figure 2}

Fresh reflux was noted in five units, of which two had undergone reimplantation into the bladder while the bowel segment had received the reimplantation in the other three. These ureters were either ectopic or obstructed megaureters preoperatively.

Febrile urinary tract infection needing antibiotic therapy was seen in four patients.

Twenty-three of our children have had a postoperative cystometry. More than 75% of the expected capacity at a safe pressure was reached in 18 of these children. Three of the five children who did not reach at least 75% of the safe capacity had undergone previous abdominal surgery.

Among the children who had both pre- and post-operative cystometrograms [Figure 3], the mean safe capacity as a percentage of the expected capacity postoperatively was 83.6% (SD = 23.9) compared to the preoperative mean of 38.1% (SD = 35.2). This increase in bladder capacity was statistically highly significant (P = 0.000).{Figure 3}

Postoperatively, external urinary leak from the catheter site (n = 8), bladder calculus (n = 1), and symptomatic mucus formation (n = 4) were noted. Only one of these children required a surgical procedure to close a urinary fistula.

There has been no intraperitoneal leakage of urine in any of these patients.

Nonurological complications included acute intestinal obstruction (n = 4), wound infection (n = 4), wound dehiscence (n = 2), and postoperative hemorrhage (n = 1).

Metabolic complications were seen in children with chronic kidney disease and included metabolic acidosis (n = 6), hypocalcemia (n = 2), electrolyte imbalance (n = 1), and renal osteodystrophy (n = 1).

 Discussion



Augmentation cystoplasty is an important procedure in pediatric reconstructive urology in spite of its complications. Surgical complications associated with bladder augmentation include perforation with intraperitoneal leakage of urine, bladder calculi, intestinal obstruction, and malignancy.[3],[4],[6],[9] Bladder perforation is a life-threatening complication, requires a high index of clinical suspicion for diagnosis, and can occur years after the augmentation procedure.[10]

In the authors' institution, there have been five perforations (2 lethal) in 100 traditional “intraperitoneal” augmentations. The reported incidence of perforation of the augmented bladder is 6%–10%.[5]

In a developing country, where many children are far from expert emergency surgical care, perforation of the augmented bladder can have serious implications. The placing of the augmentation in a preperitoneal space is our attempt to reduce the fatal consequences of perforation of the augmented bladder.

The etiology of perforation of the augmented bladder is likely to be multifactorial.[8],[9],[11],[12] Most authors stress the role of overdistension, the brunt of which has to be borne by the unsupported intraperitoneal augmentation patch which gives way in the areas of weakness. Overdistension is caused by missed or ineffective catheterization, especially if the urethral leak pressure is high. The effect of overdistension is accentuated by contractions originating in the bowel patch. Pathogenesis of weak areas in the augmentation includes mechanical factors such as suture lines, exit points of catheters placed at the time of augmentation, and those caused by repeated catheter trauma. Chronic exposure of bowel wall to infected urine could also weaken it. Chronic ischemia to portions of the augmentation patch could also be an important cause of weakness.

In our series, we have placed the augmentation patch in a preperitoneal location, which, in addition to being more akin to the normal position occupied by the child's bladder, could offer significant advantages as regards the surgical complications of bladder augmentation. The most important benefit is a reduced likelihood of intraperitoneal perforation and associated leak into the peritoneal cavity as has been seen in our series. The augmentation is supported by the parietal peritoneum posteriorly and the skin and subcutaneous tissue anteriorly, thus providing a degree of mechanical protection against disruptive forces. This arrangement allows adequate but not excessive distension. We also believe that the augmented bladder is placed in a vascularized bed, potentially allowing neovascularization of any potentially ischemic area in the augmentation patch. Other advantages in the separation of the peritoneal cavity from the augmented bladder are that subsequent intraperitoneal surgery through an upper abdominal incision (adhesion release in four children and a refluxing to nonrefluxing transureteroureterostomy in one child) could be done without interfering with the augmented bladder. Similarly, the augmented bladder can be accessed without opening the peritoneal cavity.

An important question in the technique described herein was whether it provided an adequately complaint augmentation, both in terms of cystometric measurements and in terms of clinical benefits conferred to the child. Ninety-four percent of our previously incontinent children are dry on intermittent catheterization after augmentation, most of these without a bladder neck procedure.

Uremic children (n = 13) have achieved a statistically significant (P = 0.011) fall in serum creatinine postaugmentation. Upper tract dilatations have improved or stabilized in all children, and 24 of the 26 refluxing units have ceased to reflux, many of these without a specific antireflux procedure apart from augmentation. These clinical benefits have been comparable to the published reports of traditional intraperitoneal augmentation.[2],[13],[14],[15],[16]

Postoperative cystometry was available in 23 children, and 18 of them achieved more than 75% of capacity expected for age at pressures <20 cm of water.

For children who had cystometry pre- and post-operatively, there was a highly significant increase in “safe” capacity [Figure 3], and this is comparable to reports in literature.[2]

In five children, the postoperative bladder capacity, though improved from their preoperative status, remained <50% of that expected for age. Three of these five children had scarred lower abdominal walls from previous surgery. The scarring of the lower abdominal wall, we propose, has reduced the compliance of the tissue planes within which the augmented bladder had been placed.

The fourth child had an ureterocystoplasty that in retrospect was an intrinsically small augmentation. The fifth child with bladder exstrophy continued to be incontinent and this leads to a smaller augmented bladder, as bladder filling is needed to stimulate the augmented bladder to expand and occupy the available space created in the preperitoneal compartment.

Thus, in cases of exstrophy, several factors exist which would predispose to an inadequate augmentation by the technique described herein, and we would not recommend the preperitoneal augmentation in these children.

Other situations where this technique could be inappropriate are patients with previous lower abdominal surgery.

Complications specific to the procedure include urocutaneous fistula at the site of exit of the suprapubic catheter, which needed operative closure in 1 of 12 children. This, we believe, was due to the relative proximity of the augmentation to the skin, and we have now avoided this complication by exiting the catheters through the belly of the rectus muscle and then through the skin.

In one child, postoperative intestinal obstruction was caused by a loop of bowel herniating into the preperitoneal space through the hiatus in the anterior parietal peritoneum through which the augmentation patch had been brought. The hiatus should be large enough to avoid venous compression on the pedicle passing through it but should not provide a too large gap.

 Conclusions



The preperitoneal bladder augmentation described herein provides an adequate augmentation except in children with bladder exstrophy or previous abdominal surgery.

We believe that the technique offers an advantage in lessening the likelihood of spontaneous intraperitoneal rupture of the augmented bladder, although long-term studies by multiple institutions would be required to conclusively prove this.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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