title: Pancolonic motor response to subsensory and suprasensory sacral nerve stimulation in patients with slow-transit constipation.
abstract: BACKGROUND
  Sacral nerve stimulation (SNS) is emerging as a potential treatment for patients with constipation. Although SNS can elicit an increase in colonic propagating sequences (PSs), the optimal stimulus parameters for this response remain unknown. This study evaluated the colonic motor response to subsensory and suprasensory SNS in patients with slow-transit constipation.
  
  
  METHODS
  Patients with confirmed slow-transit constipation were studied. Either a water-perfused manometry catheter or a high-resolution fibre-optic manometry catheter was positioned colonoscopically to the caecum. A temporary electrode was implanted transcutaneously in the S3 sacral nerve foramen. In the fasted state, three conditions were evaluated in a double-blind randomized fashion: sham, subsensory and suprasensory stimulation. Each 2-h treatment period was preceded by a 2-h basal period. The delta (Δ) value was calculated as the frequency of the event during stimulation minus that during the basal period.
  
  
  RESULTS
  Nine patients had readings taken with a water-perfused catheter and six with a fibre-optic catheter. Compared with sham stimulation, suprasensory stimulation caused a significant increase in the frequency of PSs (mean(s.d.) Δ value - 1·1(7·2) versus 6·1(4·0) PSs per 2 h; P = 0·004). No motor response was recorded in response to subsensory stimulation compared with sham stimulation. Compared with subsensory stimulation, stimulation at suprasensory levels caused a significant increase in the frequency of PSs (P = 0·006).
  
  
  CONCLUSIONS
  In patients with slow-transit constipation, suprasensory SNS increased the frequency of colonic PSs, whereas subsensory SNS stimulation did not. This has implications for the design of therapeutic trials and the clinical application of the device.
authors.affiliation: Department of Human Physiology, Flinders University, Bedford Park, South Australia. phil.dinning@flinders.edu.au
authors.forename: P G
authors.initials: PG
authors.lastname: Dinning
authors.forename: L M
authors.initials: LM
authors.lastname: Hunt
authors.forename: J W
authors.initials: JW
authors.lastname: Arkwright
authors.forename: V
authors.initials: V
authors.lastname: Patton
authors.forename: M M
authors.initials: MM
authors.lastname: Szczesniak
authors.forename: L
authors.initials: L
authors.lastname: Wiklendt
authors.forename: J B
authors.initials: JB
authors.lastname: Davidson
authors.forename: D Z
authors.initials: DZ
authors.lastname: Lubowski
authors.forename: I J
authors.initials: IJ
authors.lastname: Cook
mesh_terms: D000328:Adult; D000368:Aged; D003106:Colon / Q000294:innervation*; D003248:Constipation / Q000503:physiopathology / Q000628:therapy*; D018592:Cross-Over Studies; D004599:Electric Stimulation Therapy / Q000379:methods*; D004567:Electrodes, Implanted; D005260:Female; D005772:Gastrointestinal Transit / Q000502:physiology*; D006801:Humans; D008160:Lumbosacral Plexus / Q000502:physiology*; D008365:Manometry; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology; D016896:Treatment Outcome