Alloplastic bladder substitution: Are we making progress? "Beyond the Abstract," by Marco Cosentino, MD, FEBU

BERKELEY, CA (UroToday.com) - Radical cystectomy with lymph node dissection is the gold standard treatment for organ-confined muscle-invasive disease, and it is also a valid option for selected patients with high-grade non-muscle-invasive bladder cancer. However, this procedure, which is performed with a curative intent also in the elderly population, is complex and associated with a high rate of complications (17-66%). These complications, that are generally considered to be primarily attributable to the urinary tract reconstruction (UTR), have an effect on the patient’s physical and psychological well being and significantly increase the total cost of the intervention. Since we are facing a rise in life expectancy, with increases in both the elderly and the bladder cancer populations, treatment management in these patients represents an important challenge for present and future urology.

"Although many different alloplastic and biologic prostheses have been investigated during the past 50 years and more, the challenge of replacing this 'simple' organ remains, and we are still looking for a real alternative to bowel sampling."

Alloplastic materials have progressively entered the daily clinical practice of every specialty. Urology, in particular, would not be the same without devices like bladder and ureteral catheters. However, while in most specialties the use of permanent implants is possible (e.g., articular or vascular prostheses), in urology this does not seem feasible as yet owing to infections and encrustations that result from the continual exposure to urine.

Many have already attempted to develop the ideal alloplastic neo-bladder, but without success. The main causes of the failure were: deposition of connective tissue, encrustations, infections, renal failure, leakages of urine from urethral or ureteral anastomosis, and problems related to biocompatibility with silicone being the most widely used material. Ideally, a well-functioning reservoir for urine should be totally biocompatible and impermeable, have the capacity to store a sufficient volume of urine, permit filling and voluntary voiding without any pressure repercussions in the upper urinary tract, avoid any leakage of urine, resist encrustation and infection, be simple to implant and simple to remove/replace in the event of malfunction, and have an acceptable duration and cost.

A new alloplastic reservoir that meets these requirements could have enormous clinical/practical, physical, psychological, and economic benefits like:

  • duration of surgery and inpatient recovery time; reduction of readmission for complications related to bowel surgery; without bowel surgery, the operation would turn into a “simple” reimplantation of ureters and urethra, easily halving the duration of surgery and the recovery time;
  • the resultant quicker turnover of patients would permit a reduction in the waiting list for surgery;
  • an orthotopic prosthesis would have evident benefits as regards avoidance of an external stoma; a more rapid restoration of physical activities and faster progression to adjuvant therapies on account of a better physical condition;
  • reduction of cost incurred by every national health system owing to:
    1. use of the instruments needed for bowel surgery (mechanical stapler, suture needles, etc.),
    2. use of devices such as external stoma bags (in patients with ileal conduit) or pads (in incontinent patients with orthotopic reconstruction) or bladder catheters in patients performing self-catheterization, and
    3. the need for subsequent readmission to hospital.

Furthermore, the identification of such biomaterial usable as a surrogate for urothelium could be of value in the majority of pediatric pathologies that require the use of bowel and could be ideally tailored for bladder augmentation or as a graft for urethral strictures or ureteral surgery. Finally, the identification of this biomaterial may provide a new family of urologic devices as urethral or ureteral catheters usable in daily clinical practice.

Although many different alloplastic and biologic prostheses have been investigated during the past 50 years and more, the challenge of replacing this “simple” organ remains, and we are still looking for a real alternative to bowel sampling. So, the answer to the question proposed in the title (“Are we making progress?”) must be an unequivocal “no” or “insufficient.” We hope that collaboration between urologists, engineers, biologists, and biomaterialists, with the incorporation of recent developments and know-how in tissue engineering, will lead to technical and practical remedies to previous problems and the identification of all the features required for the ideal bladder prosthesis. Whether or when a biomaterial with the above-described properties will become available for commercial and medical use remains an open question.

Urologists, engineers, and industry all need to give this matter serious attention.

Written by:
Marco Cosentino, MD, FEBU as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.

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Alloplastic bladder substitution: Are we making progress? - Abstract

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