title: Sacral anterior root stimulated defecation in spinal cord injuries: an experimental study in canine model.
abstract: OBJECTIVE
  To investigate whether there was a dominant sacral root for the motive function of rectum and anal sphincter, and to provide an experimental basis for sacral root electrically stimulated defecation in spinal cord injuries.
  
  
  METHODS
  Eleven spinal cord injured mongrel dogs were included in the study. After L4-L7 laminectomy, the bilateral L7-S3 roots were electrostimulated separately and rectal and sphincter pressure were recorded synchronously. Four animals were implanted electrodes on bilateral S2 roots.
  
  
  RESULTS
  For rectal motorial innervation, S2 was the most dominant (mean 15.2 kPa, 37.7% of total pressure), S1 (11.3 kPa, 27.6%) and S3 (10.9 kPa, 26.7%) contributed to a smaller part. For external anal sphincter, S3 (mean 17.2 kPa, 33.7%) was the most dominant, S2 (16.2 kPa, 31.6%) and S1 (14.3 kPa, 27.9%) contributed to a lesser but still a significant part. Above 85% L7 roots provided some functional contribution to rectum and anal sphincter. For both rectum and sphincter, the right sacral roots provided more contribution than the left roots. Postoperatively, the 4 dogs had electrically stimulated defecation and micturition under the control of the neuroprosthetic device.
  
  
  CONCLUSIONS
  S2 root is the most dominant contributor to rectal pressure in dogs. Stimulation of bilateral S2 with implanted electrodes contributes to good micturition and defecation in dogs.
authors.affiliation: Department of Orthopedic Surgery, Tongji Hospital, Tongji University, Shanghai 200065, China. shiminchang@yahoo.com.cn
authors.forename: Shi-Min
authors.initials: SM
authors.lastname: Chang
authors.forename: Guang-Rong
authors.initials: GR
authors.lastname: Yu
authors.forename: Ying-Min
authors.initials: YM
authors.lastname: Diao
authors.forename: Meng-Jie
authors.initials: MJ
authors.lastname: Zhang
authors.forename: Shi-Bo
authors.initials: SB
authors.lastname: Wang
authors.forename: Chun-Lin
authors.initials: CL
authors.lastname: Hou
mesh_terms: D000818:Animals; D003672:Defecation; D004195:Disease Models, Animal; D004285:Dogs; D004599:Electric Stimulation Therapy / Q000379:methods*; D008297:Male; D011312:Pressure; D019736:Prostheses and Implants; D012007:Rectum / Q000294:innervation / Q000502:physiology; D012447:Sacrum; D013119:Spinal Cord Injuries / Q000628:therapy*; D013126:Spinal Nerve Roots / Q000502:physiology*; D014554:Urination