Urodynamic observations on patients with sacral anterior root stimulators.

The urodynamic changes produced by sacral anterior root stimulators have been assessed in 13 patients with spinal injuries. Before surgery all of the eleven men and two women had poor or absent bladder control with large residual volumes. Videocysto-urethrography with pressure and flow studies was performed pre-operatively and repeated once post-operatively, at intervals of 6 months to 5 years. In all cases the residual volume was reduced to less than 50 ml and the functional bladder capacity increased to within the normal range. All the patients were able to void voluntarily by activating their implants in bursts. This produced an interrupted stream at normal voiding pressures and acceptable flow rates. There was definite improvement in vesico-ureteric reflux and decrease in bladder trabeculation following implantation of the stimulator. Use of the stimulator has enabled nine of the patients to be continent at night. Eight of them are also dry during the day.