title: Effectiveness of percutaneous tibial nerve stimulation in managing refractory constipation.
abstract: OBJECTIVE
  Chronic constipation can be aetiopathogenically classified into slow transit constipation (STC), rectal evacuation difficulty (RED) or a combination (BOTH). Although the efficacy of percutaneous tibial nerve stimulation (PTNS) in faecal incontinence has been well proved, a current literature search identifies only one study which assessed its effect on constipation. We aimed to evaluate the effectiveness of PTNS in patients with different causes of constipation.
  
  
  METHODS
  Thirty-four patients [30 women, median age 50 (20-79) years] with constipation who had previously failed maximal laxative and biofeedback therapy participated in the study. All patients underwent a baseline radio-opaque marker transit study and anorectal physiology examination. All had 12 sessions of PTNS of 30 min per session. A fall in the Wexner constipation score to ≤15 or by ≥5 points was taken as the primary outcome. Secondary outcomes included the results of pre- and post- PTNS transit and anorectal physiology studies.
  
  
  RESULTS
  Eleven patients had STC, 14 had RED and nine had BOTH. A response was seen in four patients (1/11 STC, 2/14 RED and 1/9 BOTH). Comparing pre- and post- PTNS, there was no significant change in the mean Wexner score (P = 0.10). There was no change in colonic transit time among the whole population (P = 0.56) or among those with STC (P = 0.47). There was no improvement in balloon expulsion in the whole group (P = 0.73) or in patients with RED (P = 0.69).
  
  
  CONCLUSIONS
  PTNS is of no benefit to patients with constipation, whatever aetiopathogenic mechanism is responsible for the symptoms.
authors.affiliation: GI Physiology Unit, University College Hospital, London, UK.|Division of Medicine, University College London, London, UK.
authors.forename: L
authors.initials: L
authors.lastname: Kumar
authors.affiliation: GI Physiology Unit, University College Hospital, London, UK.
authors.forename: J
authors.initials: J
authors.lastname: Liwanag
authors.affiliation: GI Physiology Unit, University College Hospital, London, UK.
authors.forename: E
authors.initials: E
authors.lastname: Athanasakos
authors.affiliation: GI Physiology Unit, University College Hospital, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Raeburn
authors.affiliation: GI Physiology Unit, University College Hospital, London, UK.
authors.forename: N
authors.initials: N
authors.lastname: Zarate-Lopez
authors.affiliation: GI Physiology Unit, University College Hospital, London, UK.|Division of Medicine, University College London, London, UK.
authors.forename: A V
authors.initials: AV
authors.lastname: Emmanuel
mesh_terms: D000328:Adult; D000368:Aged; D003248:Constipation / Q000503:physiopathology / Q000628:therapy*; D005260:Female; D005772:Gastrointestinal Transit; D006801:Humans; D008297:Male; D008875:Middle Aged; D012007:Rectum / Q000294:innervation; D012720:Severity of Illness Index; D013979:Tibial Nerve; D004561:Transcutaneous Electric Nerve Stimulation / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult
keywords: Chronic constipation; intestinal transit; posterior tibial nerve stimulation; rectal evacuation