title: Anal sphincter asymmetry in anal incontinence after restorative proctectomy for rectal cancer.
abstract: OBJECTIVE
  The morphology and physiology of the anorectum can be altered after restorative proctectomy, which may result in anal incontinence. Thus far, there have been few reports regarding the specific characteristics and management of anal incontinence after rectal cancer surgery. We attempted to determine the characteristics of anorectum in anal incontinence after restorative proctectomy.
  
  
  METHODS
  We compared the clinical and physiologic factors between consecutive 138 patients with continence and 48 with iatrogenic anal incontinence at 1 year after rectal cancer resection. This study excluded patients at less than 1 year after operation or ileostomy takedown.
  
  
  RESULTS
  The two groups were comparable with regard to age, sex ratio, radiotherapy, and complication rate. The percentages of asymmetry of the resting and squeeze sphincter were significantly higher in the anal incontinence group (37.2 +/- 9.3% vs 32.5 +/- 6.7%, P = 0.01; 32.4 +/- 7.8% vs 28.3 +/- 6.3%, P = 0.011). High-pressure zone length, mean resting vector volume, and rectal compliance were not less in the anal incontinence group than in the continence group. In multivariate analysis of manometric variables, the percentages of asymmetry of the resting and squeeze were independent factors associated with anal incontinence (P < 0.05). The mean thickness of the anal cushion and internal anal sphincter did not significantly differ between the anal incontinence and continence groups.
  
  
  CONCLUSIONS
  Sphincter asymmetry is one of the hallmark characteristics of iatrogenic anal incontinence patients after proctectomy, which suggests that anal canal symmetry may be a beneficial factor with regard to anal continence.
authors.affiliation: Department of Surgery, Seoul National University Bundang Hospital, 300 Gumi-dong Bundang-gu, Seongnam-si, Gyeonggi-do 463-707, Korea. kangsb@snubh.org
authors.forename: Sung-Bum
authors.initials: SB
authors.lastname: Kang
authors.forename: Nayoung
authors.initials: N
authors.lastname: Kim
authors.forename: Kyoung-Ho
authors.initials: KH
authors.lastname: Lee
authors.forename: Young-Hoon
authors.initials: YH
authors.lastname: Kim
authors.forename: Jee Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Jae-Sung
authors.initials: JS
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001003:Anal Canal / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D016009:Chi-Square Distribution; D019160:Endosonography; D005242:Fecal Incontinence / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007049:Iatrogenic Disease; D016015:Logistic Models; D008297:Male; D008365:Manometry; D008875:Middle Aged; D016737:Proctocolectomy, Restorative; D012004:Rectal Neoplasms / Q000601:surgery*; D016896:Treatment Outcome