Investigation of bladder deformability within the development process of the artificial urinary diversion system - a pilot study.

Purpose: The purpose of this pilot study was to investigate changes in the dimensions of human bladders in different body positions to determine the required deformability of an artificial urinary diversion system (AUDS). This entirely artificial organ is comparable in size to the maximum capacity of natural bladders and is a replacement for diseased bladders, such those damaged by cancer.

Methods: The full bladders (determined by the individual's perception) of 5 healthy adult volunteers were imaged using a fully opened magnetic resonance imaging (MRI) device in different body positions: standing, maximum flexion, and seated. Dimensional changes were measured in four directions (ventral, dorsal, cranial and caudal) using a custom graphical method based on midsagittal images; the standing position was used as the reference position.

Results: The maximum flexed position was compared to the reference position, and the largest change was found in the cranial extension of the bladders: 6±4.2 mm (mean±SD). The seated and reference positions were compared; the maximum change was in the cranial extension and was measured to be 18±2.8 mm.

Conclusions: The results indicate the requirement for a highly deformable artificial bladder in specific directions, such as the cranial and dorsal directions, which influences the positions of the technical components within the artificial organ. In a future development stage, artificial bladders will be designed using a computer-aided design system based on the results from this study and possibly a subsequent similar study.