A hybrid physical-neural phantom of the urinary bladder incorporating the spinal pudenda-vesical reflex

Spinal cord injury (SCI) is the most common cause of bladder dysfunction. When bladder control is impaired after SCI, it not only disrupts normal bodily function but also severely impacts quality of life. The primary management method – intermittent catheterisation – carries a high risk of urinary tract infections. Recent work has demonstrated that electroneurogram (ENG) recordings from the sacral roots can be used to infer bladder pressure; however, progress is limited by the scarcity of biological data. Few artificial bladder models exist to support device development, and none integrate the mechanical and neurophysiological aspects of the lower urinary tract. Here, we present the first closed-loop artificial bladder system driven by a spiking neural model of sacral micturition reflexes, which is validated against biological recordings. The system reproduces the bladder pressure response observed in vivo, demonstrating a close match to ewe cystometry data. The significance of this platform lies in its ability to generate synthetic data, support neuromodulation testing, and provide a foundation for implantable bladder control systems.