I have to have a neurotransmitter put in for bladder control please explain to me how this is done & why its is done. thank you.

InterStim: Neuro modulation is a therapy for overactive bladder usually. It can sometimes also help people who cannot empty their bladder. A small wire is placed through the skin and into the sacral foramen of the appropriate nerves controlling the bladder. This is tunneled to an implanted subcutaneous battery that creates a continuous stimulus to the nerve. It looks and works much like a cardiac pacemaker.