[Experimental study on combining selective rhizotomy of different anterior and posterior sacral roots for restoration...

To investigate an alternative procedure for complete denervation of bladder in the supra-cone cord injury to restore the bladder function.

Sixteen dogs were included in this study after their spinal cords were transected above the cone. They were divided into 6 groups and performed the rhizotomy of L7 to S3 root in different combination respectively. The bladder and urethra pressure change by electrostimulation during operation and cystometrogram change after operation were tested.

1. Electrostimulation study: for bladder innervation, S2 was the most important and S1 was secondary. While for urethra innervation, S1 was more important than S2. When the anterior and posterior roots of S1 and S2 were intact with rhizotomy of posterior roots of L7 and S3, stimulated the common or posterior root of S1 and S2, the change of pressure in bladder and urethra was the same. When the anterior roots of S1 and S2 were resected with rhizotomy of posterior roots of L7 and S3, the pressure in bladder and urethra was significant decreased compared to stimulating the corresponding posterior roots. 2. Cystometrogram (CMG) study: in the complete deafferented group, resecting the posterior roots of L7 to S3, the bladder became flaccid. While resecting the posterior root of S2 and anterior root of S1 or, resecting the posterior root of S1 and anterior root of S2, combining with rhizotomy of posterior roots of L7 and S3, the CMG curve was similar to the complete deafferented group. In the S1 and S2 intact group, the bladder became spastic.

Combining rhizotomy of anterior and posterior sacral root in different level has the same effects on bladder as complete deafferentation.