“…In sacral anterior root stimulation, a pressure-free bladder ¢lling is ensured by means of additionally performed dea¡erentiation [Hohenfellner et al, 1992]. However, Bross et al have been able to show that the contractility of the detrusor decreases through overextension of the bladder, meaning that there is a maximum functional bladder capacity which must not be exceeded (also avoiding the opposite extreme) if optimal stimulation-induced bladder contractions are to be obtained [Huxley, 1969;Bross et al, 1997;Seif et al, 2002]. If therefore, a bladder ¢lling that is either too high or too low leads to generation of residual urine, there is an optimal voiding time [Huxley, 1969;Uvelius and Gabella, 1980;Kaplan et al, 1991;Brindley, 1994;Bross et al, 1997].…”