OBJECTIVETo evaluate the results of a self-designed bladder controller for restoring micturition function in paraplegic dogs.

METHODSThe spinal cords of 4 dogs were transected above the cone. Electrodes were implanted in S2 bilaterally and connected to the subcutaneous receivers for external activation. Microsurgical technique was employed to perform dorsal rhizotomy of S1-3 intradurally. The dogs were stimulated daily to observe micturition. Urodynamic testing and vesicography were performed.

RESULTSAll the dogs acquired micturition under the control of electric stimulation, with urine volume 80-140 ml per time. The mode of micturition was post-stimulus voiding. Vesicography revealed that the bladder was filled well and the bladder neck was open in the micturition course of electric stimulation. Residual urine volume was 15-20 ml. Urodynamic testing found that the bladder pressure and intraurethral pressure increased simultaneously, but when the intraurethral pressure was greater than the bladder pressure, no micturition occurred. The pressure decreased to baseline rapidly and the bladder pressure decreased slowly between two bursts. Micturition occurred when the bladder pressure was greater than the intraurethral pressure.

CONCLUSIONSThe self-designed bladder controller together with a sacral deafferentation procedure can restore micturition function of paraplegic dogs.