There is high malignancy, recurrence and distant metastasis in the invasive bladder cancer. The current standard of treatment is still the radical cystectomy combined with urinary diversion, and its surgical procedure is complicated, also there is a high incidence of postoperative complications[16]. The anastomosis of the ureteral stump and free ileal intestinal fistula is the key technical points of the operation, which directly determines the incidence of the ureter stricture and the postoperative hydronerhrosis.
Through our meta-analysis, we found that the rates of stricture and hydronephrosis in the separate group were higher than those of the conjoined anastomosis group. And there was no heterogeneity on the basis of the chi-square-based Cochran’s Q statistic test[10], in which p < 0.1. Stricture is a serious postoperative problem, and the conjoined anastomosis has a lower incidence than the separate anastomosis. Therefore, it become a common technique to handle ureteroileal anastomotic strictures and hydronephrosis[17, 18]. The separate technique requires a surgical closure technique for the end of the ileum in addition to the ureteroileal anastomosis, while the two ureters are combined and connected to the end of the afferent limb by the end-to-end method in the conjoined anastomosis, therefore, there is low rate of stricture complications in neobladder reconstructions[12].
There was no heterogeneity in the hydronephrosis group according to our meta-analysis, and the overall rate of hydronephrosis was 23.1%. The hydronephrosis rate of conjoined anastomosis as lower that of the separate anastomosis. The separate anastomosis requires the left ureter to travel to the right through the posterior sigmoid mesenteric approach, thus causing compression of the left ureter; while the left ureter needs to travel to the right and anastomosis with the intestinal fistula, which will lead to excessive ureteral distraction, excessive tension, resulting in ischemic stenosis of the left ureter. Studies have shown that the separate anastomosis can lead to postoperative complications due to changes in the anatomical position of the ureter, and it occurs mostly in the ureteral anastomosis[19].
The separate and conjoined anastomosis procedures are the most common techniques used for urinary diversion after bladder cancer[20]. Both techniques have some limitations. The separate technique has a higher rate of stricture and hydronephrosis, with a possibility of upper urinary tract recurrence[21]. Surgeons choose the anastomosis depending on patient characteristics. The limitations of early studies include the lack of classification of complications of the two anastomosis, and there is little data comparison in the early studies[22].
The incidence of complication of conjoined anastomosis is low, which can lead to recurrence of the upper urinary tract tumor and block both ureters, causing uremia from bilateral obstruction[5]. There are several risk factors for upper urinary tract recurrence, including prostatic urethra involvement, ureteral involvement or positive ureteral margin, and recurrent tumor[23]. Therefore, the conjoined technique is not used for patients with recurrent tumor or carcinoma of the ureters[24].
Surgeons choose different techniques according to different situations. Ureteral length after retrosigmoidal tunneling is a factor influencing the choice of anastomosis technique. The conjoined technique is better when the ureteral length is similar on both sides, while the separate technique is preferred when lengths are disparate.
Admittedly, there were also some limitations to our study. First the number of studies included was small: only six studies compared the two types of anastomosis, and there were few randomized trials, therefore clinical heterogeneity was inevitable. Second, the impact of unpublished research was not considered, therefore, there might be some publication bias or selection bias. Third, there are other complications after surgery that were not included in our analysis. Meanwhile, the number of patients was low, introducing possible search bias.
Conclusions
The effect of surgical methods on the quality of life after surgery is increasingly a concern of urological surgeons[25]. If we want reduce the rate of stricture and hydronephrosis, we can choose conjoined anastomosis. Surgeons should choose the technique according to patients’ characteristics.