A Soft Robotic Detrusor Based on Balloon Hydraulic Actuators for Artificial Bladder Voiding

Bladder cancer and urinary dysfunctions represent significant challenges to human health and patients' quality of life. Radical cystectomy is the primary treatment for muscle-invasive bladder cancer, but the associated bladder reconstruction surgery is unable to replicate the voiding capabilities of the native organ. In this scenario, the development of an implantable artificial bladder with controlled voiding capabilities has the potential to overcome the limitations of current clinical solutions. This study explores the synergy between an artificial bladder and an active artificial detrusor constituted by two soft actuators integrated on a soft sleeve. In particular, hydraulic balloon actuators have been selected to enhance the voiding performances of the artificial bladder while preserving softness for smooth and minimally-invasive implantation. Experimental results demonstrate that the actuators can reach a displacement of 31.0 ± 0.7 mm at 40 mL inlet volume and generate output forces of 26.4 ± 3.4 N, 6.8 ± 1.4 N, and 1.5 ± 0.4 N at 25%, 50%, and 75% of the maximum displacement, respectively. The soft detrusor enables promising voiding capabilities of the artificial bladder in terms of Post-Voiding Residual (PVR) volume, Voiding Efficiency (VE), and Voiding Time (VT), reaching values equal to 2.2 ± 2.0 mL, 98.9 ± 1.0 %, and 83.9 ± 4.7 s, respectively.