Augmentation cystoplasty remains the surgical treatment of choice for the medically resistant neurogenic and nonneurogenic overactive bladder. The management goals are the provision of a low-pressure, large-volume storage reservoir typically emptied by clean intermittent catheterization (CIC) to provide renal preservation, continence, and a low risk of urinary tract infections (UTIs). Studies confirm a significant improvement in quality of life of patients and treatment with a durable outcome (1
). Lifelong follow-up is required due to the high rate of complications and the potential need for reoperation. Concern for malignancy following bladder augmentation seems to have waned, and regular cystoscopic surveillance is not recommended. Future prospects of tissue engineering to provide an augmentation patch remain in evolution. Patients with incontinent urinary diversions like ileal conduits more frequently develop UTIs and upper tract deterioration compared to those with large, low-pressure reservoir employing the urethra as a continence method (2
The indications for augmentation cystoplasty remain the medically resistant overactive bladder from neuropathic and nonneuropathic origin. The four main groups of patients presenting for AC are congenital, idiopathic, inflammatory, and neuropathic in etiology (Table 22.1
Patients with congenital abnormalities present during surveillance after primary treatment with either risks of renal deterioration or persistent incontinence. The goals are a high-volume, low-pressure bladder with an ability to fully empty by CIC.
Patients with chronic inflammatory conditions need to have malignancy ruled out first by cystoscopic assessment and bladder biopsy.
Intractable incontinence from idiopathic detrusor overactivity is an indication for augmentation cystoplasty. In this group, the renal function is rarely at risk and treatment is aimed at managing incontinence. The initial treatments may include anticholinergic medication, sacral nerve stimulation therapy, botulinum toxin detrusor injection, and detrusor myomectomy (11
). Postoperatively, a number of these patients can void efficiently but most require CIC, and it should be trialed preoperatively to confirm patient compliance.
In patients with a neuropathic bladder, the goals of management are renal preservation, continence, and protection against UTIs. These patients need to be intelligent, well-motivated, supported, have adequate hand function, and be able to undertake CIC. The majority of patients require CIC to empty their bladder to reduce the risk of UTI. Patients with progressive neurologic or cognitive diseases such as multiple sclerosis and/or dementia are poor candidates for augmentation cystoplasty because their ability to perform CIC may deteriorate with time. This makes them more dependent on caregivers for catheterization or a long-term catheter, which puts them at risk of recurrent UTIs. Those patients unable to catheterize because of their anatomy such as a wheelchair-bound female spina bifida patient should be considered for a continent catheterizable stoma (Mitrofanoff) along with an augmentation. Patients unable to self-catheterize because of their anatomy, motivation, hand function, or intelligence could lastly be considered for an incontinent urinary diversion. There is an integral role for continence nurse practitioners here to assess patients and families preoperatively and troubleshoot postoperative
problems. These vital colleagues increase the patients’ ability to remain independent and have good outcome.
TABLE 22.1 LIST OF INDICATIONS
Congenital bladder abnormalities: bladder exstrophy/epispadias, posterior urethral valves
Inflammatory: tuberculosis, schistosomiasis, radiotherapy, and chemotherapy (e.g., cyclophosphamide)
Chronic functionless bladder: vesicostomy, cutaneous ureterostomy
Neuropathic: spina bifida, spinal cord injury, other congenital neuropathic bladder
In general, patients with significantly impaired renal function are a relative contraindication to augmentation cystoplasty because reabsorption of electrolytes can increase their risk of acidosis and further impairment of renal function. In a contrary view, however, augmentation cystoplasty may protect against further reduction in renal function and is useful in patients who require renal transplantation secondary to severe bladder dysfunction. Careful follow-up is required in this patient group to prevent dehydration, maintain regular bladder emptying to reduce the risk of acidosis, and acute medical problems.
The cornerstone of bladder assessment is video urodynamics. This assesses the bladder and the outlet and should confirm the decision to proceed with augmentation cystoplasty. The presence or absence of vesicoureteral reflux can be confirmed. However, reflux is typically a secondary phenomenon and is generally not surgically corrected with a ureteric reimplant (13
). Reflux is usually corrected by increasing capacity and lowering the pressure of the bladder.
Assessment of the bladder outlet remains difficult. This is undertaken by incorporating patient history, renal function, and observation during urodynamics. The abdominal leak point pressure measures outlet resistance and suggests whether an outlet procedure should be undertaken with augmentation. Occasionally, urethral pressure profilometry and sphincter electromyography are used.
Bowel Segment Options
The bowel segments used depend on availability and the presence of any preexisting bowel disease (8
). Ileum is the preferred bowel of choice after retaining 20 cm of terminal ileum for gut absorption. The expanding use of the appendix as a Malone antegrade continence enema (MACE) procedure for bowel management makes the cecum and terminal right ileum often somewhat adhered within the peritoneal cavity, reducing its mobility (14
). Ileum is still used in the majority of these circumstances for augmentation, and if required, the MACE may be done synchronously or asynchronously with augmentation.
Gastrocystoplasty was increasingly used especially where short bowel syndrome is a potential consequence of further bowel segment removal and the bladder and the gastric wall seen as easier to tunnel a catheterizable channel through. More recently, this has reduced in popularity and is now contraindicated due to the increased risk of malignancy (7
). The ileocecal region had been popular in the past, combining the terminal ileum and the cecum in an augmentation patch. This is not recommended due to increased risk of bowel dysfunction due to the loss of the ileocecal valve. The sigmoid colon has been used where small bowel will not easily mobilize into the pelvis. It is thicker walled and occasionally large and redundant in neuropaths where there is associated constipation.
Colocystoplasty has, however, been shown to have increased mucus production, a greater risk of urinary infection and a greater risk of complications requiring reoperation, and thus, it is a secondary choice for augmentation (15
Ileum, as previously stated, remains the most popular bowel segment due to its mobility, lower production of mucus, and lower long-term complications.
More recently, several options have become available for the resistant overactive bladder. Botulinum toxin injections have been shown to be effective in both the neuropathic and nonneuropathic population. Given the low morbidity of this procedure, it can be tried prior to augmentation cystoplasty; however, its high cost and need for repeat injections are a barrier to widespread use, especially in younger patients (11
). Sacral nerve stimulation has been used for refractory urge incontinence due to the nonneuropathic causes (12
). It has not proven to be as popular due to the lower success rates and cumbersome implant.
Autoaugmentation of the bladder, also known as detrusor myomectomy, involves the excision of detrusor muscle over the dome and anterior wall of the bladder. This theoretically allows a diverticulum of epithelium to distend, thereby improving storage capacity and bladder compliance. This procedure is significantly less morbid, has the advantage of not incorporating mucus-producing bowel into the urinary tract, and almost uniformly allows patients to void spontaneously. Despite this, it has been less successful and it is not recommended in neuropathic patients (16
). It has a small role in nonneuropathic patients who are younger with intractable urge incontinence especially associated with persistent nocturnal enuresis. Laparoscopic and robotic bladder augmentation has been reported, but this procedure is still investigational (17
Other nonautologous tissue such as Teflon, Silastic, Gore-Tex, and bovine dura have been used for augmentation, but complications associated with bladder anastomosis, contracture, fistula, leakage, and stone formation have precluded their use (8
). Tissue engineering is an innovative alternative. A small clinical trial has been reported in children with spina bifida. However, the short-term and long-term results have not been as promising. Clinical trial and experimental work are still under way to improve this novel alternative (10
The principles of augmentation cystoplasty are to enlarge the bladder with detubularized bowel segment, providing a highcapacity lower pressure reservoir. Twenty to 30 cm of detubularized ileum can be patched as U or straight patch. This bowel needs to be placed in the pelvis without tension and remain well vascularized. The bladder is split in the sagittal or coronal plane widely to reduce the risk of an hourglass diverticulum forming. Absorbable sutures are used in a single-layer anastomosis and suprapubic plus urethral or stoma catheter drainage is required postoperatively. The patient should be taught CIC prior to augmentation cystoplasty because the majority will need to do this for emptying. If a continent catheterizable channel is to be used, stoma position should be confirmed preoperatively. If the patients are to have a concurrent MACE procedure, the continent diversion channel should be placed on the left side or in the umbilicus.
No special bowel preparation is required with normal diet allowed up until the day before surgery with clear fluids on the day of surgery up until 2 to 6 hours preoperatively. Due to the low or absent bacterial count in the terminal ileum, no
bowel preparation is recommended. Prophylactic intravenous antibiotics are routine especially in patients with a ventriculoperitoneal (V-P) shunt where this should be manipulated out of the operation site if becomes visible during surgery.
FIGURE 22.1 Patient position, supine with table extension to improve pelvic access.
The patients are placed supine on the operating theatre table with a slight table break to allow better access to the pelvis (Fig. 22.1
). A catheter is placed into the urinary tract and the bladder emptied immediately preoperatively. A midline incision may be extended above the umbilicus if necessary and a laparotomy performed. A self-retaining retractor, a ring, or Bookwalter-type retractor is useful to improve access. A Pfannenstiel incision is occasionally undertaken, but it may be difficult to get access to the peritoneal cavity to bring the ileum down especially in neuropaths where the terminal ileum may be prefixed due to the lumbar lordosis.