title: Rectal evacuation and antegrade colonic luminal transport by sacral anterior root stimulation in pigs.
abstract: OBJECTIVE
  Electrical sacral anterior root stimulation with a selective anodal block may relieve difficulties with bowel evacuation by selective colorectal activation and anal sphincter suppression. This study compares rectal evacuation induced by anodal block with that induced by unselective stimulation.
  
  
  METHODS
  The sacral anterior roots were stimulated with cuff electrodes in seven chloralose-anesthetized minipigs. Anodal block and unselective stimulation were applied in random order and compared by anorectal manometry and by the obtained colorectal evacuation. Evacuation was quantified scintigraphically after retrograde radioactive paste installation.
  
  
  RESULTS
  Unselective stimulation evoked sphincter activation which obstructed rectal evacuation during the 30-second stimulation period, after which poststimulation evacuation occurred (mean, 13%; P < 0.05). Anodal block reduced the anal canal pressure by median 83% compared with unselective stimulation. With unrestrained evacuation, a different evacuation pattern (mean, 18%; P < 0.05) occurred within the first ten seconds of the stimulation period and evacuated volume was higher (P = 0.08). Colonic evacuation reached a mean of 17% with unselective stimulation and 11% with anodal block.
  
  
  CONCLUSIONS
  Anodal block and unselective sacral root stimulation induce rectal evacuation and colonic luminal transport in pigs. However, anodal block may improve stimulation-induced defecation by enabling a near-physiologic defecation pattern.
authors.affiliation: Surgical Research Unit, Department of Surgery P, Aarhus University Hospital, Aarhus, Denmark. fvm@ki.au.dk
authors.forename: Flemming V
authors.initials: FV
authors.lastname: Møller
authors.forename: Steen
authors.initials: S
authors.lastname: Buntzen
authors.forename: Nico J M
authors.initials: NJ
authors.lastname: Rijkhoff
authors.forename: Søren
authors.initials: S
authors.lastname: Laurberg
mesh_terms: D000818:Animals; D003106:Colon / Q000503:physiopathology*; D003672:Defecation / Q000502:physiology*; D004599:Electric Stimulation Therapy / Q000379:methods*; D004567:Electrodes, Implanted; D005260:Female; D005769:Gastrointestinal Motility / Q000502:physiology*; D007413:Intestinal Mucosa / Q000503:physiopathology; D008160:Lumbosacral Plexus; D012007:Rectum / Q000503:physiopathology*; D013126:Spinal Nerve Roots; D013552:Swine; D013556:Swine, Miniature