Chronic stimulation of the sacral roots in dogs.

To investigate the feasibility of chronic stimulation of the sacral nerves for control of sphincter and bladder function, we implanted bipolar electrodes in 10 dogs. These electrodes, of conventional cuff (4 dogs), as well as innovative spiral designs (6 dogs) were placed around the S2 roots of the 10 dogs and in 3 of them around the S1 root additionally. The electrodes were connected to subcutaneous radiofrequency receivers for external activation. Microsurgical techniques were employed to perform dorsal rhizotomy and ganglionectomy. 5 dogs, 3 kept as long as 8 months, were chronically stimulated to a cumulated time of 100-150 h each. Functional and histological results reveal that sacral root nerves can be stimulated safely on a chronic basis for effective control of the lower urinary tract.