title: Improving the efficacy of sacral nerve stimulation for faecal incontinence by alteration of stimulation parameters.
abstract: BACKGROUND
  Sacral nerve stimulation (SNS) is an effective treatment for faecal incontinence, but only standard stimulation parameters have been used. This study assessed the clinical impact of altering the parameters.
  
  
  METHODS
  Twelve patients with partially improved faecal incontinence following SNS underwent acute testing to select optimal stimulation parameters; rectal compliance was used as a surrogate marker. Parameters tested were: stimulation off; frequency 14 (standard), 31 or 6.9 Hz; and pulse duration 210 (standard), 450 or 90 micros. Patients completed a 2-week bowel diary, St Mark's continence score (SMCS) and Rockwood faecal incontinence quality-of-life (FIQL) score before testing using standard settings, and after testing using optimized settings.
  
  
  RESULTS
  Optimal settings, determined by greatest increase in rectal compliance, were shorter pulse width in five patients and higher frequency in seven. Optimized stimulation resulted in a decrease in mean episodes of incontinence from 2.3 to 1.2 per week (P = 0.031), soiling from 3.3 to 1.7 days per week (P = 0.016), faecal urgency from 31 to 18 per cent of all evacuations (P = 0.055) and SMCS from 12.3 to 8.7 (P = 0.008); the FIQL coping/behaviour score improved (P = 0.008).
  
  
  CONCLUSIONS
  With a shorter pulse width and higher frequency, clinical efficacy in patients undergoing SNS for faecal incontinence can be improved.
authors.affiliation: Physiology Unit, St Mark's Hospital, London, UK.
authors.forename: T C
authors.initials: TC
authors.lastname: Dudding
authors.forename: C J
authors.initials: CJ
authors.lastname: Vaizey
authors.forename: A
authors.initials: A
authors.lastname: Gibbs
authors.forename: M A
authors.initials: MA
authors.lastname: Kamm
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D004599:Electric Stimulation Therapy / Q000379:methods*; D004812:Epidemiologic Methods; D005242:Fecal Incontinence / Q000628:therapy*; D005260:Female; D006801:Humans; D008160:Lumbosacral Plexus; D008875:Middle Aged; D011788:Quality of Life; D016896:Treatment Outcome