| This study is aimed to restore bladder function (storing and voiding) in spinal cord injuries (SCI) through an intrathecal approach that performed on the cauda equina and sacral roots. It involves (1) an anatomical observation of canine spinal cone, cauda equina, and sacral roots, (2) an electrical stimulation study of differential sacral roots to determine their innervative frequency and efficacy to bladder detrusor and urethral sphincter, as well as (3) to rectum and anal sphincter. Then (4) an alternative procedure to complete sacral de-afferentation was investigated in 16 dogs. With the promising results of experimental study, (5) clinical applications were carried out in 3 supraconal SCI patients with spastic bladder selected by urodynamics.In canine anatomic study, Three specific features that different from human beings were identified. First, the neural innervations to the pelvic organs are provided by SI, S2 and S3 spinal cord segments and the corresponding sacral roots. Second, the conus medullaris extends long and terminates at the 6th lumbar vertebrae, whereas the cauda equina is relatively short. Third, the ventral and dorsal roots of spinal nerves are surrounded by its own meningeal tubes separately for 1 to 1.5cm, till the point of dorsal root ganglion.In electrical stimulation study, the bilateral L7桽3 roots were electrostimulated separately and urodynamic vesical and urethral pressures, or manometric rectal and anal pressures, were recorded simultaneously. For bladder innervation, S2 is the most dominant, which contributed 45.2% of total pressure uprising; S~ plus ~2 contributed 80.7%. For sphincterinnervation, S~ is the most dominant, which provided 43.4% of total pressure uprising, S~ plus S2 provided 76.7%. For rectal innervation, S2 is the most dominant, which contributed 37.3% of total pressure uprising, S and S3 contributed lesser extent, 27.6% and 26.7%, respectively. For sphincter, 53 is the most dominant, which contributed 33.7% of total pressure uprising, S1 and ~2 contributed lesser but still significant extent, 31.6% and 27.9%, respectively. For both bladder and urethra, or rectum and ana, the right sacral roots provided more contributions than the left ones. Although to a minimal extent, yet in most dogs, the L7 roots provide functional innervations to bladder (56%), urethra (78%), rectum (85%), and anal sphincter (100%).To investigate an alternative procedure for complete sacral deafferentation, sixteen T10 spinal cord transected dogs were included. They were divided into 6 groups according to different level, extent, and combination of anterior and posterior rhizotomy of sacral roots. Intraoperative electrostimulation study: In conditions of preserving S~ (or S2) anterior and posterior root intact combined with L7, ~2 (or S1) and S3 posterior roots rhizotomies, Stimulation of S~ (or S2) posterior root gave a similar pressure rising in bladder and urethra as stimulation of its common root. However, in conditions of section 5, (or ~2) anterior root combined with L7, ~2 (or 5,) and 53 posterior roots rhizotomies, stimulating S~ (or 52) posterior root gave a minimal pressure rising in bladder and urethra, which was only about 10% to that of stimulating the same posterior root while its anterior counterpart was intact. Postoperative CMG study: In groups of preserving 5, (or S2) anterior and posterior root intact combined with L7, ~2 (or S~) and S3 posterior rhizotomies, CMG is similar to the free group, which tends to become a hypertonic, hyperreflexic and spastic bladder. In groups of resecting S~ (or S2) anterior root combined with L7, ~2 (or S~) and S3 posterior rhizotomies, CMGAis similar to that of the complete L1 to 53 posterior roots rhizotomies, which tends to become a hypotonic, hyporeflexic and flaccid bladder. In conclusion, combined cross rhizotomy of anterior (partial de-efferentation) and posterior(iartial de-afferentation) sacral roots in different spinal cord levels has the same denervative effects on abolition of bladder and urethra...
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