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Abstract Purpose The clinical, urodynamic and endoscopic aspects of the Stanford pouch ileal neobladder formed with absorbable staples were investigated.
Methods A Stanford pouch ileal neobladder was formed using absorbable staples after radical cystoprostatectomy in 30 male patients with the diagnosis of muscle invasive carcinoma of the bladder between 1995 and 1998. The mean age of the patients was 62 (range 41–70) years. Patients were followed with arterial blood gas, serum biochemistry, pouch cystography, urodynamic tests and endoscopy.
Results Five (16.7%) patients had early postoperative complications and three were related to the neobladder. One year postoperatively, low grade (I, II) vesicoureteral reflux was present in five (16.7%) cases. The mean preoperative and 6 months postoperative serum creatinine levels were 1.07 ± 0.3 mg/dL and 1.2 ± 0.4 mg/dL, respectively, but the difference was not statistically significant (P = 0.1). Six months postoperatively the mean serum chloride level was 109 ± 4.5 (range 100–113) mmol/L and the mean arterial blood pH was 7.37 ± 0.2 (range 7.3–7.4). Two (6.7%) patients required oral alkaline supplementation because of high chloride levels. All the patients except one were continent throughout the day after 1 year. However, nocturnal enuresis was present in 25 (83.3%) cases. The pouch capacity was increased gradually up to 12 months postoperatively and the mean pouch capacity 12 months postoperatively was 460 ± 95.8 mL. Micturition occurred spontaneously in most patients while some needed abdominal straining. None of the patients had a residual urine of more than 60 mL. The mean maximum flow rate 6 months postoperatively was 9.8 (range 5.4–15.0) mL/s. After 6 months the stapled edge was noticed as a nodular line. One year postoperatively only a white scar could be observed at the suture line.
Conclusion The Stanford pouch ileal neobladder constructed using absorbable staples was able to provide a good capacity–low pressure reservoir with a low rate of complications.
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Many different techniques have been described for orthotopic neobladders using different gastrointestinal segments. The incorporation of intestinal segments into the bladder is known to cause problems such as malabsorption and metabolic disturbances.2 We prefer to use the Stanford pouch ileal neobladder as it requires the use of only 40 cm of ileum and it is technically simple.4 A disadvantage of this pouch may be an increase in pressure according to the La Place law (pressure = tension/radius); however, this does not seem to be applicable because of the inherent capacity of intestine to distend.5 It is shown that the Stanford pouch could provide a good capacity without an increase in pressure.5,6 In our patients the capacity of ileal neobladder was found to increase gradually in time up to 12 months postoperatively. The mean pouch capacity at that time reached 460 mL and no significant change occurred thereafter. Urodynamic tests performed in 28 patients with a Stanford pouch by Iwakiri et al. also confirmed good reservoir characteristics with an average capacity of 699 mL at an average follow-up of 18 months.6 In the same series, mean post voiding residual urine was reported as 137 mL. Considering their high neobladder capacity when compared to our patients, it is not surprising that none of our patients had a residual urine more than 60 mL.
Good compliance is probably the most important factor for the maintenance of continence in ileal neobladder patients.5,6 As a result of good compliance, 93% of patients in the report by Iwakiri et al. were continent throughout the day. All our cases except the one who pulled out his catheter were also day-time continent (96.7%). Night-time continence was achieved in 61% of patients of Iwakiri et al. and was reported to be 84% by Boyd et al.7 and 92% by Miller et al.8 When compared to these reports the incidence of nocturnal incontinence was considerably higher (83.3%) in our patients, but this rate represents night-time incontinence when the patient did not wake up for voiding. This could also be partly attributed to relatively lower pouch capacity and shorter follow-up period during which the patients were instructed to void at set times also during the night. As the pouch capacity increases with time, the frequency of night-time voids should be individualized for each patient. Our final impression is that most cases could achieve night-time continence by waking up at least twice per night after 1 year from the operation. Similarly, the average time to achieve night-time continence was found to be 8 (range 2–24) months in the series of Iwakiri and Freiha.5 They observed that 78% of their cases needed to void at least once to stay dry at night and the average number of voids/night to maintain continence was two. The authors found no significant difference in basal neobladder pressure, phasic contraction pressure and maximum urethral closure pressure between night-time continent and incontinent patients. However, a significant difference was present with regard to compliance between day-time continent and incontinent cases.
Another disadvantage of the Stanford pouch is the high rate of vesicoureteral reflux. Vesicoureteral reflux was present in 62% of Iwakiri and Freiha's cases; however, this neither produced any detrimental effect on renal function nor resulted in febrile urinary tract infections.5 We observed that 3 weeks postoperatively, 71% of the patients had various degrees of reflux which was decreased to 16.7% after 1 year and no febrile urinary tract infections occurred. The increase in pouch capacity with time and good plication of the afferent limb were possibly the important factors to decrease the rate of reflux.
All of the patients in our series could urinate spontaneously with a mean maximum flow rate of 9.8 mL/s. The physiology of micturition in the ileal neobladder is rather different than the native bladder as the intestine has no voluntary motor innervation. The ileal neobladder depends on the pressure generated in the reservoir upon filling for the evacuation of the bladder.9 When the patient desires to void, the outlet resistance is decreased by pelvic floor relaxation and voiding occurs. However, some patients may need abdominal straining to provide extra pressure to facilitate voiding.9,10 As the patient lost the afferent feedback between the detrusor and central nervous system, a rise in ileal neobladder pressure upon filling may cause leakage of the urine.9,10 Therefore patients must learn how to relax and contract their pelvic muscles to provide both continence and successful voiding process, which takes time. Problems can arise due to insufficient relaxation of the pelvic musculature because of residual urine, namely overdistention, infection and calculus formation.6,11 Chronic overdistention of the reservoir also increases the risk of metabolic abnormalities because of increased contact time.2,9 The Stanford pouch is a good type of ileal neobladder in this regard as it utilizes a short segment of bowel and produces a relatively small but sufficient reservoir capacity as in our study. Mikuma et al. stated that voiding dysfunction in ileal neobladder could be a result of incorrect location of the bladder outlet,12 which emphasizes the importance of good surgical technique. The early complication rate (16.7%) in our series is similar to previous reports; however, as the follow-up period is short, long-term complication rates are not available.5 Recently, Hautmann et al. published the long-term complications and functional results of the Hautmann pouch ileal neobladder in 363 patients.11 The early and late complication rates were 39% and 32%, respectively, but the Hautmann pouch utilized a longer segment of ileum and was constructed by a different technique.
The ileal neobladder was also found to be safe with regard to acid–base balance. We observed hyperchloremic acidosis in only two (6.7%) patients who promptly responded to the treatment. Similarly, Racioppi et al. recently reported the incidence of hyperchloremic acidosis as 7.9% in patients with ileal and ileocecal neobladder and found no difference between the two techniques with regard to acid–base imbalance.13 Preservation of renal function; villous atrophy and decrease in absorptive capacity with time; the use of a short segment of ileum; and low amount of residual urine are probably the most important advantages of the Stanford pouch which protects the patient from metabolic disturbances. It was shown that the length of the ileum resected correlated with absorption capacity, and 50 cm was the critical margin for vitamin B12 absorption from the ileum.14,15 Accordingly, patients with the Stanford pouch ileal neobladder would probably have a lower risk for vitamin B12 malabsorption.
An important technical point in our series is the use of automatic staplers loaded with absorbable staples for the construction of the pouch. Radical cystectomy and construction of the ileal neobladder is a lengthy and technically demanding procedure. The use of automatic staplers and absorbable staples not only shortens the operation time but simplifies the procedure as well. The invention of absorbable staples has led to more widespread use of continent reservoirs because of technical simplicity. Montie et al. compared the ‘W’ stapled ileal reservoir with hand sewn reservoirs and reported that 32% of the cases in stapler group had poor reservoir characteristics.16 They suggested that the ischemia of the anterior ileal segment between adjacent stapler lines might be the cause of fibrosis and poor distention of the reservoir. They also observed that septations persisted in the reservoir at sites where adjacent limbs were not anastomosed entirely. Probably, the ‘W’ configuration and the technique were the main problems in that series. However, Paolini et al.17 and Altugˇet al.18 used the automatic staplers for the construction of ileal neobladders with good functional results. Other authors also showed the utility of GIA absorbable staples in the construction of Indiana pouches and ileocecal reservoirs.19,20 We did not face any problems in pouch capacity and compliance due to the use of absorbable staples. This may partly be related to the rather simple configuration of the Stanford pouch. The main disadvantages of absorbable staples are the need to divide the septum with scissors when the length of the staplers is insufficient for the construction of the whole pouch and the rigidity of the suture line. After 1 year, we observed only a white scar at the suture line endoscopically.
In conclusion, the Stanford pouch ileal neobladder constructed with absorbable staples was able to provide a good capacity–low pressure reservoir with a low rate of complications. The use of absorbable staples not only shortens the operation time but also simplifies a technically demanding procedure. Short-term results with regard to renal function and acid–base status are also encouraging. However, the patients must be instructed to void at set times during the day and also at night to achieve continence. As the pouch capacity increases with time, the frequency of night-time voids should be individualized for each patient.