Sigmoid neobladder as an ideal form of orthotopic urinary reconstruction


Hideaki Miyake M.D., Division of Urology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan. Email:

To date, various procedures for creating an orthotopic neobladder following radical cystectomy have been reported.1 Although the type of neobladder that provides the best outcomes is disputed, the ileal neobladder (INB) may currently be the most frequently selected form of neobladder worldwide.2 At our institution, however, sigmoid neobladder (SNB) has been preferred for patients undergoing radical cystectomy irrespective of their characteristics.3–7

As previously described,3,4 we modified several steps of the original method to create SNB in order to minimize postoperative complications.8 For example, rotation of the reservoir upside-down and 180° horizontally provides a tension-free enterourethral anastomosis and successfully prevents urethral ischemia (Fig. 1a), while the implantation of ureters to the upper edge of the reservoir facilitates the creation of a submucosal tunnel and allows precise ureterointestinal anastomosis (Fig. 2). In fact, the incidence of complications in our SNB series, including ureterointestinal strictures, enterourethral strictures and vesicoureteral reflux, were lower than that in other SNB series.1–4,6,7

Figure 1.

Creation of a sigmoid pouch showing, (a) the isolated sigmoid colon was detubularized along the antimesenteric border; (b) the detubularized segment was folded in a U-shape and the colonic wall was closed by a running suture through all intestinal layers; (c) the reservoir created was inverted, and rotated upside-down and 180° horizontally (cited from Fujisawa et al.3).

Figure 2.

Ureterointestinal anastomosis. Each ureter was pulled through the submucosal tunnel, which was easily created at the upper edge of the reservoir, and ureterointestinal anastomosis was performed employing six interrupted sutures (cited from Fujisawa et al.3).

Of the several problems associated with neobladder, voiding dysfunction probably has the most adverse impact on a patient's postoperative satisfaction. In general, despite an unfavorable continence status, particularly night-time continence, SNB is likely to acquire an adequate voiding status by emptying the reservoir.7,9,10 Furthermore, in our series the favorable voiding status of SNB was confirmed; that is, more than 90% of the patients could void spontaneously, and their post-void residual urine was less than 25 mL (Table 1).5,6 Furthermore, daytime and night-time continence rates in SNB were approximately 85 and 60%, respectively, which appeared to be markedly superior to those in previously reported outcomes in SNB (Table 1).5–7,9,10 Considering the low compliance of SNB due to the physiological features of the sigmoid colon characterized by a high pressure with powerful contraction of the thick wall, we used a longer sigmoid segment (35–40 cm) than used in other studies, resulting in an increase in the pouch volume and its compliance. In addition, a small post-void residual urine, which has been shown to influence continence with a neobladder,10 may also have contributed to the favorable continence status in our SNB series.

Table 1.  Functional outcomes (cited from Miyake et al.5)
 Total (N = 80)Gender
Male (n = 62)Female (n = 18)P-value
  • Based on data from 77 patients after excluding three who voided with CIC alone. CIC, clean intermittent catheterization.

Voiding status (%)    
 Voiding with no assistance73 (91.3)56 (90.4)17 (94.4)0.63
 Voiding with CIC assistance4 (5.0)3 (4.8)1 (5.6)
 Voiding with CIC alone3 (3.7)3 (4.8)0 (0)
Continence status (%)    
 Daytime continence69 (86.9)54 (91.5)15 (83.3)0.32
 Nighttime continence46 (59.7)36 (61.0)10 (55.6)0.68
Voiding function    
 Maximal flow rate (mL/s)18.6 ± 9.717.8 ± 9.521.2 ± 13.90.24
 Voided volume (mL)345.3 ± 118.9339.5 ± 141.5364.2 ± 158.70.53
 Post-void residual urine (mL)24.5 ± 22.427.2 ± 24.015.7 ± 38.40.13

It has been well documented that the voiding status of neobladders in women tends to be more frequently impaired over time than in men; however, in our studies, there was no significant difference in voiding status between male and female patients with SNB (Table 1).4,6 In addition, despite the lack of a significant difference in the continence status between women with SNB and INB, there were significant differences in the proportion of spontaneous voiders and post-void residual urine between the two groups, being more favorable in women with SNB.6

Other than the issues described above, there are some more advantages in selecting SNB, such as the low incidence of urinary tract infection in its use. It also has little effect on metabolic and nutritional status and preserves the renal function.3–7 Collectively, these findings suggest that the reconstruction of orthotopic SNB could facilitate at least equivalent or even better clinical outcomes than that of INB, particularly in women, considering their favorable postoperative voiding status.

Conflict of interest

None declared.