title: Total mesorectal excision with intraoperative assessment of internal anal sphincter innervation provides new insights into neurogenic incontinence.
abstract: BACKGROUND
  The aim of this prospective study was to assess internal anal sphincter (IAS) innervation in patients undergoing total mesorectal excision (TME) by intraoperative neuromonitoring (IONM).
  
  
  METHODS
  Fourteen patients underwent TME. IONM was carried out through pelvic splanchnic nerve stimulation under continuous electromyography of the IAS. Anorectal function was assessed with the digital rectal examination scoring system and a standardized questionnaire.
  
  
  RESULTS
  Nine of 11 patients who underwent low anterior resection had positive IONM results, with stimulation-induced increased IAS electromyographic amplitudes (median 0.23 μV (interquartile range [IQR] 0.05, 0.56) vs median 0.89 μV (IQR 0.64, 1.88), p < 0.001) after TME. The patients with the positive IONM results were continent after stoma closure. Of 2 patients with negative IONM results, 1 had fecal incontinence after closure of the defunctioning stoma and received a permanent sigmoidostomy. In the other patient the defunctioning stoma was deemed permanent due to decreased anal sphincter function. In 3 patients who underwent abdominoperineal excision, IONM assessed denervation of the IAS after performance of the abdominal part.
  
  
  CONCLUSIONS
  This study demonstrated that IONM of IAS innervation in rectal cancer patients is feasible and may predict neurogenic fecal incontinence.
authors.affiliation: Department of General and Abdominal Surgery, University Medicine of the Johannes Gutenberg-University Mainz, Mainz, Germany. werner.kneist@unimedizin-mainz.de
authors.forename: Werner
authors.initials: W
authors.lastname: Kneist
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Kauff
authors.forename: Ines
authors.initials: I
authors.lastname: Gockel
authors.forename: Sabine
authors.initials: S
authors.lastname: Huppert
authors.forename: Klaus P
authors.initials: KP
authors.lastname: Koch
authors.forename: Klaus P
authors.initials: KP
authors.lastname: Hoffmann
authors.forename: Hauke
authors.initials: H
authors.lastname: Lang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001003:Anal Canal / Q000294:innervation*; D001341:Autonomic Nervous System / Q000502:physiology*; D004576:Electromyography; D005240:Feasibility Studies; D005242:Fecal Incontinence / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000601:surgery*; D012007:Rectum / Q000601:surgery*; D011795:Surveys and Questionnaires; D016896:Treatment Outcome