Spinal-cord injury produces incontinence and, or retention due to lower urinary tract deficiency. Repetitive catheterizations induce multiples complications at several levels (Sphincter, bladder and kidneys). The bladder hyperreflexia (simultaneous contractions of the bladder and the sphincter) is hardly curable with traditional Medicine.
Reported solution for the recuperation of the bladder function is electrical stimulation. But conventional electrical neuronal stimulation (ENS) of the bladder induces contraction on both detrusor and sphincter, thus preventing from complete voiding while conventional ENS combined with nerve rhizothomy is not accepted by patients.
Our team proposed dual electrical stimulation technique: Selective neuronal stimulation allows efficient voiding of the bladder, and Permanent low frequency to reduce or even suppress hyperreflexia symptoms and maintain the bladder shape. The stimulation techniques corresponding devices have been designed and realised by our team: a selective stimulator and a dual implantable stimulator.
The next step is going toward total integration. A new integrated stimulator has been designed to allow voluntary bladder voiding, suppress hyperreflexia symptoms and monitor the nerve impedance. Impedance measurement is commonly used to characterize electrodes-tissues contacts in implantable stimulators. Also, a new selective stimulation technique allow the generation of waveforms created with multiple stimulation patterns. Each pattern is created using previously programmed amplitude values with variable pulse widths and frequencies. The chip has been fabricated in a CMOS 0.18um process and occupies 4mm2. The preliminary experimental results proved most parts of its functionality.
