Bladder Substitution: The Role of Tissue Engineering and Biomaterials

Tissue engineering could play a major role in the setting of urinary diversion. Several conditions cause the functional or anatomic loss of urinary bladder, requiring reconstructive procedures on the urinary tract. Three main approaches are possible: (i) incontinent cutaneous diversion, such as ureterocutaneostomy, colonic or ileal conduit, (ii) continent pouch created using different segments of the gastrointestinal system and a cutaneous stoma, and (iii) orthotopic urinary diversion with an intestinal segment with spherical configuration and anastomosis to the urethra (neobladder, orthotopic bladder substitution). However, urinary diversions are associated with numerous complications, such as mucus production, electrolyte imbalances and increased malignant transformation potential. In this context, tissue engineering would have the fundamental role of creating a suitable material for urinary diversion, avoiding the use of bowel segments, and reducing complications. Materials used for the purpose of urinary substitution are biological in case of acellular tissue matrices and naturally derived materials, or artificial in case of synthetic polymers. However, only limited success has been achieved so far. The aim of this review is to present the ideal properties of a urinary tissue engineered scaffold and to examine the results achieved so far. The most promising studies have been highlighted in order to guide the choice of scaffolds and cells type for further evolutions.

Long-term outcomes of sigmoid neobladder after radical cystectomy in Indian population: a single centre experience

Background: Radical cystectomy with orthotopic neobladder is the standard of care for MIBC. Long-term data on sigmoid neobladder is limited. Sigmoid neobladder offers the advantage of low long-term metabolic and nutritional complications, due to sparing of ileum and ileo-caecal valve. We present our experience and long-term results of orthotopic sigmoid neobladder reconstruction after radical cystectomy.Methods: The study included 57 male patients who underwent radical cystectomy and orthotopic sigmoid neobladder for muscle-invasive carcinoma of bladder from January 2002 to December 2019. Data was collected with regards to complication rate, voiding patterns, continence status, recurrence-free and overall survival.Results: Mean age was 52.7 years (range 35 to 74). Median duration of follow-up was 62 months. There were 3 (5.3%) perioperative deaths. 15 patients (26.3%) developed early and 5 patients (8.7%) developed delayed complications. Node positive disease (N+) was found in 11 (19.3%) patients and 17 (29.8%) required adjuvant chemotherapy. 94.7% patients were continent and 42 (82.4%) patients had spontaneous voiding pattern. Daytime and nocturnal incontinence rate were 5.3% and 24.6%, respectively. Clean intermittent catheterization (CIC) was required in 8 (14.1%) cases. The recurrence-free survival (RFS) and overall survival (OS) were 57% and 50% at 5 years and 62.5% and 35.8% at 10 years, respectively.Conclusions: Sigmoid neobladder remains a viable form of orthotopic urinary diversion and provides satisfactory long-term continence and voiding results with acceptable rate of complications. Good long-term results in sigmoid neobladder in Indian population may be due to long sigmoid colons in Indian patients with low incidence of diverticulosis.

Treatment and outcomes of urethral recurrence after orthotopic neobladder replacement in patients with bladder cancer — practice in a single centre

Objectives To report on the treatment of urethral recurrence after orthotopic urinary diversion at our institution. Methods We retrospectively reviewed clinical information of urethral recurrence in patients who underwent radical cystectomy and orthotopic urinary diversion between January 1998 and January 2013. Results Of 341 patients, 282 presented for follow-up (median follow-up: 56 months; range: 1–174 months). Eight patients developed local recurrence of urothelial cancer after radical cystectomy. The rate of urethral recurrence (1.4%) in female patients who underwent orthotopic urinary diversion was lower than in male patients (3.3%). The median (range) time to recurrence was 33 (6–120) months after radical cystectomy and orthotopic urinary diversion. Recurrences were treated by transurethral resection of tumour, urethrectomy, neobladder resection, revision of urinary diversion, adjuvant chemotherapy, or radiation therapy, based on individual circumstances. Survival analysis showed that 5-year cancer-specific survival was significantly higher in patients with urethral recurrence alone (83.3%), compared with patients with other recurrences, including pelvic/abdomen recurrence and distant metastasis (26.8%). Conclusions En bloc urethrectomy and revision of urinary diversion remain the principle surgical choices. Selection of transurethral tumour resection was based on tumour stage and was used in carefully chosen patients. Cancer-specific survival might depend on multidisciplinary therapy.