title: Does Sacral Nerve Stimulation Improve Continence Through Enhanced Sensitivity of the Anal Canal? A Pilot Study.
abstract: BACKGROUND
  It has been suggested that the effects of sacral nerve stimulation against fecal incontinence involve neuromodulation at spinal or supraspinal levels.
  
  
  OBJECTIVE
  This study aims to investigate the afferent sensory pathways from the anorectum before and during sacral nerve stimulation.
  
  
  METHODS
  This is an explorative study.
  
  
  METHODS
  Fifteen women with idiopathic fecal incontinence (mean age, 58 ± 12.2 years) were selected.
  
  
  METHODS
  Cortical evoked potentials were recorded during repeated rapid balloon distension of the rectum and the anal canal both before and during temporary sacral nerve stimulation. Stimuli applied were individualized according to the subjective urge to defecate.
  
  
  METHODS
  The main outcomes measured were 1) stimulus intensity, 2) latencies and amplitudes of cortical evoked potentials, and 3) spectral content in predefined frequency bands of cortical evoked potentials.
  
  
  RESULTS
  The median Wexner fecal incontinence score improved from 15.5 ± 3.6 before to 6.7 ± 5 during sacral nerve stimulation (p < 0.001). Sacral nerve stimulation did not affect the threshold for urge to defecate during rectal distension (p = 0.64) but reduced the threshold from stimulation of the anal canal by 50% (p = 0.03). No statistically significant differences were found in latencies, amplitudes, or spectral analysis.
  
  
  CONCLUSIONS
  This is a pilot study of limited size.
  
  
  CONCLUSIONS
  In patients with idiopathic fecal incontinence, sacral nerve stimulation reduced the threshold for urge to defecate elicited from the anal canal, whereas supraspinal responses remained unaltered. This may suggest that sacral nerve stimulation, at least in part, acts via somatic afferent fibers enhancing anal sensation.
authors.affiliation: 1Department of Surgery P, THG, University Hospital, Aarhus, Denmark 2Mech-Sense, Department of Gastroenterology & Hepatology, Aalborg University Hospital, Aalborg, Denmark 3Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark 4Department of Clinical Medicine, Aalborg University, Aalborg, Denmark 5Neurogastroenterology Unit, Department of Hepatology and Gastroenterology, University Hospital, Aarhus, Denmark.
authors.forename: S
authors.initials: S
authors.lastname: Haas
authors.forename: C
authors.initials: C
authors.lastname: Brock
authors.forename: K
authors.initials: K
authors.lastname: Krogh
authors.forename: M
authors.initials: M
authors.lastname: Gram
authors.forename: L
authors.initials: L
authors.lastname: Lundby
authors.forename: A M
authors.initials: AM
authors.lastname: Drewes
authors.forename: S
authors.initials: S
authors.lastname: Laurberg
mesh_terms: D000368:Aged; D001003:Anal Canal / Q000294:innervation / Q000503:physiopathology; D005073:Evoked Potentials, Somatosensory; D005242:Fecal Incontinence / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D005260:Female; D006801:Humans; D008160:Lumbosacral Plexus / Q000503:physiopathology*; D008365:Manometry / Q000379:methods; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D010865:Pilot Projects; D012007:Rectum / Q000294:innervation / Q000503:physiopathology; D004561:Transcutaneous Electric Nerve Stimulation / Q000379:methods*