title: Preoperative MRI sphincter morphology and anal manometry: can they be markers of functional outcome following anterior resection for rectal cancer?
abstract: OBJECTIVE
  Good functional outcome following anterior resection (AR) for rectal cancer is an important clinical goal, but its prediction has proven difficult. Assessments such as anal manometry have been advocated as a potential tool but functional anatomy as depicted on MRI has not been investigated. This study looked at whether sphincter complex measurements recorded from preoperative staging MRIs and preoperative anal manometry have any correlation with functional outcome.
  
  
  METHODS
  Consecutive patients with rectal adenocarcinoma underwent preoperative manometric assessment and MRI staging. MRIs were assessed with regard to anorectal angle, puborectalis thickness, canal length and external and internal anal sphincter thickness. Functional outcome was categorized into three groups according to the number of adverse postoperative symptoms (frequency, urgency, leakage, diarrhoea, use of pads, use of antidiarrhoeal medication): 0, 1 and ≥ 2. This was evaluated 1 year following surgery and 6 months following stoma reversal where applicable. Univariate analysis of an ordinal regression model was performed with significance at the 5% level.
  
  
  RESULTS
  Thirty patients were assessed. No single preoperative manometric parameter proved significant (P > 0.05). Only puborectalis thickness showed a significant (P = 0.01) relationship with the number of adverse symptoms suffered postoperatively. On receiver operating characteristics analysis, a cut-off value of 3.5 mm gave an optimal sensitivity of 0.5 (95% CI, 0.17-0.83) and specificity of 0.86 (95% CI, 0.64-0.96).
  
  
  CONCLUSIONS
  Measurements of the puborectalis thickness on preoperative staging MRIs for rectal cancer may help predict functional outcome following AR. Prospective assessment of larger numbers with a fully validated continence score are required to evaluate these findings further.
authors.affiliation: Pelican Cancer Foundation, Dinwoodie Drive, Basingstoke, UK. pd_how@hotmail.com
authors.forename: P
authors.initials: P
authors.lastname: How
authors.forename: J
authors.initials: J
authors.lastname: Evans
authors.forename: B
authors.initials: B
authors.lastname: Moran
authors.forename: I
authors.initials: I
authors.lastname: Swift
authors.forename: G
authors.initials: G
authors.lastname: Brown
mesh_terms: D000230:Adenocarcinoma / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001003:Anal Canal / Q000033:anatomy & histology* / Q000502:physiology*; D000930:Antidiarrheals / Q000627:therapeutic use; D003967:Diarrhea / Q000188:drug therapy / Q000209:etiology; D005242:Fecal Incontinence / Q000209:etiology; D005260:Female; D006801:Humans; D016496:Incontinence Pads; D008279:Magnetic Resonance Imaging; D008297:Male; D008365:Manometry; D008875:Middle Aged; D011183:Postoperative Complications / Q000188:drug therapy / Q000209:etiology*; D011237:Predictive Value of Tests; D057234:Preoperative Period; D012372:ROC Curve; D012004:Rectal Neoplasms / Q000601:surgery*
chemical_list: D000930:Antidiarrheals