Augmentation Cystoplasty

Bladder augmentation, also called augmentation cystoplasty, is a surgical procedure used in adults and children who lack adequate bladder capacity or detrusor compliance. ^{[1, 2, 3]} For many patients, augmentation cystoplasty can provide a safe, functional reservoir that allows for urinary continence and prevention of upper tract deterioration.

Both neuropathic and non-neuropathic causes for severe bladder dysfunction exist in pediatric and adult populations. Neuropathic causes include the following:

• Spinal cord injury

• Multiple sclerosis

• Myelodysplasia

• Tethered spinal cord

Nonneuropathic causes include the following:

• Detrusor instability

• Chronic cystitis, including tuberculosis and schistosomiasis

• Interstitial cystitis

• Radiation cystitis

• Classic or cloacal exstrophy

• Defunctionalized bladder in a patient who is on dialysis

Decreased bladder capacity or abnormal compliance may manifest as debilitating urgency, frequency, incontinence, recurrent urinary tract infections (UTIs), pyelonephritis, or progressive renal insufficiency.

Various studies used to evaluate such symptoms may reveal severe dysfunction. Urodynamic studies demonstrate a low-volume, poorly compliant reservoir, which places the kidneys at risk from high-pressure urinary storage. Simultaneous fluoroscopic videourodynamic evaluation may reveal vesicoureteral reflux. Renal ultrasonography or other imaging modalities may show renal scarring or impaired renal growth due to high-pressure urinary storage.

Any patient with marked reduction in bladder capacity or compliance may be a candidate for augmentation cystoplasty. Conservative management for these patients usually consists of intermittent self-catheterization ^[4] and anticholinergic medications. In general, augmentation cystoplasty is considered when bothersome symptoms impair a patient’s lifestyle despite medical treatment or when high-pressure urinary storage places the upper urinary tracts at risk. In an updated clinical guideline, the American Urological Association stated that augmentation cystoplasty may be considered for patients with severe, refractory, complicated overactive bladder. ^[5]

Neurogenic bladder in the pediatric population is often associated with congenital anomalies, including the following:

• Spina bifida/myelomeningocele ^{[6, 7]}

• Posterior urethral valves

• Prune belly syndrome (Eagle-Barrett syndrome)

• Bladder exstrophy

• Cloacal exstrophy

Patients with these conditions most commonly undergo augmentation cystoplasty when, despite behavioral and medical management, they experience continued incontinence, debilitating urgency, enuresis, complicated UTIs, vesicoureteral reflux, or impaired renal growth.

Some adult patients who underwent urinary diversion for an embryologic urinary defect as a child seek a healthier cosmetic and functional state. In other cases, adults have an acquired condition that is causing bladder dysfunction. Adults may present with symptoms very similar to those of children with congenital abnormalities. Again, surgery is indicated for adults with refractory symptoms and those with risk or progression of upper tract deterioration.

Patients who are unable or unwilling to perform life-long intermittent catheterization should not undergo augmentation cystoplasty, because of the high likelihood that catheterization will ultimately be required.

In addition, patients with inflammatory bowel disease (especially Crohn disease), a short or irradiated bowel, bladder tumors, severe radiation cystitis, or severe renal insufficiency should not undergo augmentation cystoplasty.

Poor surgical candidates and patients with a short life expectancy should consider alternatives to augmentation cystoplasty, such as continued medical management or creation of a less complex, temporizing form of urinary drainage.

The anatomy of the bladder forms an extraperitoneal muscular urine reservoir that lies behind the pubic symphysis in the pelvis. A normal bladder functions through a complex coordination of musculoskeletal, neurologic, and psychological functions that allow filling and emptying of the bladder contents. The prime effector of continence is the synergic relaxation of detrusor muscles and contraction of the bladder neck and pelvic floor muscles.

The normal adult bladder accommodates 300-600 mL of urine; a central nervous system (CNS) response is usually triggered when the volume reaches 400 mL. However, urination can be prevented by cortical suppression of the peripheral nervous system or by voluntary contraction of the external urethral sphincter.

Before being considered for augmentation cystoplasty, patients should have timed voids as often as necessary to maintain low bladder volume and pressure.

Anticholinergic medications (eg, oxybutynin, hyoscyamine, or tolterodine) may be given to decrease detrusor instability and symptoms of urgency. Medical management also allows increased bladder volume to protect renal function and to decrease the chance of pyelonephritis. The increase in bladder capacity with medical treatment has been modest (generally < 50 mL), but some groups have found that higher doses may increase the effect, as one study demonstrated in young children with neurogenic bladders. ^[8]

Cystoscopic injection of botulinum toxin (botox) can also decrease involuntary detrusor contractions and increase functional capacity. In the setting of poor bladder capacity and outlet obstruction, botulinum toxin can be added to a regimen of clean intermittent catheterization.

Lack of coordinated detrusor contraction or increased bladder outlet obstruction (eg, external sphincter dyssynergia) can be overcome with intermittent self-catheterization at 4- to 6-hour intervals. This usually reduces bladder pressure and improves continence. Adult patients should have good manual dexterity, proven by performing self-catheterization in front of the physician. In pediatric patients, the parents must be committed to catheterizing the child at least every 4-6 hours. Parents must be taught catheterization before surgery.

Intermittent catheterization and anticholinergic management are usually used in combination to accomplish symptom-management goals, to create continence, to eliminate vesicoureteral reflux, to prevent UTIs, and to ensure low bladder storage pressure. If these measures fail, augmentation cystoplasty should be considered.

In properly selected patients, augmentation cystoplasty is an excellent procedure that provides a safe and effective way of improving urinary storage. Bladder emptying is almost universally impaired, and the patient must be prepared to perform lifelong intermittent catheterization. The patient and physician must recognize the need for surveillance to identify potential problems. Stones, metabolic and nutritional abnormalities, renal insufficiency, and malignancy are best treated through early recognition and prompt therapy. ^{[9, 10]}

Herschorn et al, using a survey to address complications and patient satisfaction in an augmentation cystoplasty population, found that at a mean of 6 years after surgery, 41% of the patients had 1 or more complications, with 36% of all patients requiring intervention. ^[11] Most took medications (eg, anticholinergics, antidiarrheals, or antibiotics). Of 59 patients, 56 required clean intermittent catheterization at a mean interval of 4.6 hours; 18% had postoperative bowel dysfunction, and 7% had preoperative dysfunction.

Schlomer et al analyzed 1622 augmentation cytoplaties performed on children between 2000 and 2009. A complication was identified in 30% of patients. Longer hospital stays and increased risk for having complications were associated with older age and bladder exstrophy-epispadias complex diagnosis. ^[12]

Alternative approaches

McGuire et al compared patients treated with augmentation cystoplasty to patients treated with autoaugmentation and determined that whereas autoaugmentation causes less morbidity, commonly reduces symptoms, and routinely improves bladder compliance, the gains in bladder capacity were much less than those seen with augmentation cystoplasty. ^[13]

This study stratified patients by etiology of bladder dysfunction and compared urodynamic and symptomatic improvement. ^[13] Patients with myelomeningocele did not fare as well with autoaugmentation because of the smaller increases in bladder capacity, and augmentation cystoplasty was more beneficial in these patients. Reportedly, autoaugmentation was unsuccessful in 27% of the patients who required augmentation cystoplasty.

Hedican et al used laparoscopy to mobilize the intestine in complex pediatric procedures, including augmentation cystoplasty. ^[14] They found laparoscopy useful in mobilizing the right colon and in isolating the appendix for a continent catheterizable stoma. A smaller lower-midline or Pfannenstiel incision can be used for surgery on the bladder or for re-establishment of bowel continuity.

Laparoscopic autoaugmentation has also been shown to be technically feasible. Braren and Bishop performed laparoscopic autoaugmentation in 7 pediatric female patients aged 3 months to 15 years; bladder capacity increased 55-95%, all 7 patients showed symptomatic improvement, and 6 of the 7 were completely dry. ^[15]

With the advent of robotic instruments with increased range of motion and the facilitation of intracorporeal suturing, many reconstructive procedures including bladder augmentation have become more amenable to fully laparoscopic procedures. ^[16] These procedures may decrease morbidity, reduce intra-abdominal adhesions, and improve body self-image.