title: Urodynamic study of women in urinary retention treated with sacral neuromodulation.
abstract: OBJECTIVE
  We investigated the action of sacral neuromodulation in restoring voiding function in women with urinary retention attributable to sphincter overactivity (Fowler's syndrome).
  
  
  METHODS
  We recruited women within retention who were able to void following neuromodulation by temporary test stimulation or a permanent implant. Urethral pressure profiles, cystometry and sphincter electromyography were performed before and after neuromodulation.
  
  
  RESULTS
  A total of 30 women 19 to 52 years old were recruited, including 21 with a permanent implant and 9 undergoing temporary stimulation. Mean maximum urethral closure pressure was elevated compared to expected pressure and it did not change significantly after neuromodulation. The electromyographic abnormality persisted during neuromodulation and voiding was often done with an interrupted flow. There was a slight increase in detrusor contractility.
  
  
  CONCLUSIONS
  This evidence suggests that neuromodulation does not restore voiding in these patients by a direct relaxant effect on the sphincter. The modest increase in detrusor pressure appears to be sufficient to overcome the resistance of the overactive sphincter.
authors.affiliation: Department of Uro-Neurology, National Hospital for Neurology and Neurosurgery, London, United Kingdom.
authors.forename: Ranan
authors.initials: R
authors.lastname: DasGupta
authors.forename: Clare J
authors.initials: CJ
authors.lastname: Fowler
mesh_terms: D000328:Adult; D004599:Electric Stimulation Therapy / Q000379:methods; D005260:Female; D006801:Humans; D008160:Lumbosacral Plexus; D008875:Middle Aged; D016055:Urinary Retention / Q000503:physiopathology* / Q000628:therapy*; D014563:Urodynamics